149 results on '"Luxon BA"'
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2. Pegylated interferons for the treatment of chronic hepatitis C infection.
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Luxon BA, Grace M, Brassard D, and Bordens R
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BACKGROUND: Interferon (IFN) alfa is a clinically effective therapy used in a wide range of viral infections and cell-proliferative disorders. Combination therapy with IFN alfa-2b and ribavirin is the current standard of care for the treatment of chronic hepatitis C (CHC) infection. However, standard IFN alfa has the drawbacks of a short serum half-life and rapid clearance. To overcome this problem, 2 pegylated forms of IFN have been developed and tested clinically. OBJECTIVE: This article reviews the development and properties of pegylated IFN alfa-2b and pegylated IFN alfa-2a, and presents safety and efficacy data from recent clinical trials. METHODS: Relevant clinical studies were identified through a MEDLINE search from 1966 through the present using the key words hepatitis C and interferon. Studies of the pegylated IFNs in humans were then selected. RESULTS: Pegylated IFN alfa-2b is formed by covalent conjugation of a 12-kd mono-methoxy polyethylene glycol (PEG) molecule to IFN alfa-2b, and pegylated IFN alfa-2a by covalent conjugation of a 40-kd branched mono-methoxy PEG molecule to IFN alfa-2a. The 2 pegylated IFNs differ in the mixture of pegylation isomers resulting from their conjugation chemistry. Pegylated IFN alfa-2b has a prolonged serum half-life (40 hours) relative to standard IFN alfa-2b (7-9 hours). The greater polymer size of pegylated IFN alfa-2a acts to reduce glomerular filtration, markedly prolonging its serum half-life (72-96 hours) compared with standard IFN alfa-2a (6-9 hours). In clinical studies, once-weekly dosing of the pegylated IFNs was associated with a sustained virologic response in patients infected with hepatitis C virus (HCV). Once-weekly dosing with either of the pegylated IFNs was more effective than the respective thrice-weekly regimen of IFN alfa, with a comparable safety profile. The combination of once-weekly pegylated IFN and ribavirin effectively reduced HCV viral load and sustained viral suppression. CONCLUSIONS: Once-weekly dosing with either pegylated IFN alfa-2b or pegylated IFN alfa-2a has been shown to produce significantly higher rates of viral eradication than standard thrice-weekly IFN alfa therapy without compromising safety. With respect to the treatment of CHC, the greatest anti-HCV efficacy has been achieved with the combination of once-weekly pegylated IFN and ribavirin. [ABSTRACT FROM AUTHOR]
- Published
- 2002
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3. Proteomic analysis of Pichindé virus Infection Identifies Differential Expression of Prothymosin-alpha.
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Bowick GC, Soman KV, Wang H, Aronson JF, Luxon BA, Lomas LO, Gorenstein DG, and Herzog NK
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The arenaviruses include a number of important pathogens including Lassa virus and Junin virus. Presently, the only treatment is supportive care and the antiviral Ribavirin. In the event of an epidemic, patient triage may be required to more effectively manage resources; the development of prognostic biomarker signatures, correlating with disease severity, would allow rational triage. Using a pair of arenaviruses, which cause mild or severe disease, we analyzed extracts from infected cells using SELDI mass spectrometry to characterize potential biomarker profiles. EDGE analysis was used to analyze longitudinal expression differences. Extracts from infected guinea pigs revealed protein peaks which could discriminate between mild or severe infection, and between times post-infection. Tandem mass-spectrometry identified several peaks, including the transcriptional regulator prothymosin-alpha. Further investigation revealed differences in secretion of this peptide. These data show proof of concept that proteomic profiling of host markers could be used as prognostic markers of infectious disease. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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4. Optimizing liver health before and after gene therapy for hemophilia A.
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Ragni MV, Mead H, de Jong YP, Kaczmarek R, Leavitt AD, Long B, Nugent DJ, Sabatino DE, Fong S, von Drygalski A, Walsh CE, and Luxon BA
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- Humans, Dependovirus genetics, Genetic Vectors, Factor VIII genetics, Hemophilia A therapy, Hemophilia A genetics, Genetic Therapy methods, Liver metabolism, Liver pathology
- Abstract
Abstract: Gene therapy for severe hemophilia A uses an adeno-associated virus (AAV) vector and liver-specific promoters that depend on healthy hepatocyte function to achieve safe and long-lasting increases in factor VIII (FVIII) activity. Thus, hepatocyte health is an essential aspect of safe and successful gene therapy. Many people living with hemophilia A have current or past chronic hepatitis C virus infection, metabolic dysfunction-associated steatosis or steatohepatitis, or other conditions that may compromise the efficacy and safety of AAV-mediated gene therapy. In addition, gene therapy may induce an immune response to transduced hepatocytes, leading to liver inflammation and reduced FVIII activity. The immune response can be treated with immunosuppression, but close monitoring of liver function tests and factor levels is necessary. The long-term risk of hepatocellular carcinoma associated with gene therapy is unknown. Routine screening by imaging for hepatocellular carcinoma, preferable every 6 months, is essential in patients at high risk and recommended in all recipients of hemophilia A gene therapy. This paper describes our current understanding of the biologic underpinnings of how liver health affects hemophilia A gene therapy, and provides practical clinical guidance for assessing, monitoring, and managing liver health both before and after gene therapy., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)
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- 2024
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5. Edson Lee Forker.
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Luxon BA
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- 2024
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6. Loss of alcohol dehydrogenase 1B in cancer-associated fibroblasts: contribution to the increase of tumor-promoting IL-6 in colon cancer.
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Villéger R, Chulkina M, Mifflin RC, Markov NS, Trieu J, Sinha M, Johnson P, Saada JI, Adegboyega PA, Luxon BA, Beswick EJ, Powell DW, and Pinchuk IV
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- Humans, Alcohol Dehydrogenase, Fibroblasts metabolism, Lipopolysaccharides metabolism, Tretinoin, Vitamin A metabolism, Cancer-Associated Fibroblasts metabolism, Colonic Neoplasms pathology, Interleukin-6 metabolism
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Background: Increases in IL-6 by cancer-associated fibroblasts (CAFs) contribute to colon cancer progression, but the mechanisms involved in the increase of this tumor-promoting cytokine are unknown. The aim of this study was to identify novel targets involved in the dysregulation of IL-6 expression by CAFs in colon cancer., Methods: Colonic normal (N), hyperplastic, tubular adenoma, adenocarcinoma tissues, and tissue-derived myo-/fibroblasts (MFs) were used in these studies., Results: Transcriptomic analysis demonstrated a striking decrease in alcohol dehydrogenase 1B (ADH1B) expression, a gene potentially involved in IL-6 dysregulation in CAFs. ADH1B expression was downregulated in approximately 50% of studied tubular adenomas and all T1-4 colon tumors, but not in hyperplastic polyps. ADH1B metabolizes alcohols, including retinol (RO), and is involved in the generation of all-trans retinoic acid (atRA). LPS-induced IL-6 production was inhibited by either RO or its byproduct atRA in N-MFs, but only atRA was effective in CAFs. Silencing ADH1B in N-MFs significantly upregulated LPS-induced IL-6 similar to those observed in CAFs and lead to the loss of RO inhibitory effect on inducible IL-6 expression., Conclusion: Our data identify ADH1B as a novel potential mesenchymal tumor suppressor, which plays a critical role in ADH1B/retinoid-mediated regulation of tumor-promoting IL-6., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)
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- 2023
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7. Vascular endothelial growth factor promotes the activation of hepatic stellate cells in chronic schistosomiasis.
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Luo J, Liang Y, Kong F, Qiu J, Liu X, Chen A, Luxon BA, Wu HW, and Wang Y
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- Actins metabolism, Animals, Antigens, Helminth immunology, Cell Proliferation, Chronic Disease, Collagen metabolism, Cytokines metabolism, Endothelin-1 metabolism, Endothelium, Vascular immunology, Female, Fibrosis genetics, Human Umbilical Vein Endothelial Cells, Humans, Liver parasitology, Mice, Mice, Inbred BALB C, Schistosomiasis japonica drug therapy, Transcriptome, Endothelium, Vascular metabolism, Hepatic Stellate Cells immunology, Liver pathology, Schistosoma japonicum immunology, Schistosomiasis japonica immunology, Vascular Endothelial Growth Factor A metabolism
- Abstract
The activation of hepatic stellate cells (HSCs) is a key event in fibrotic pathogenesis. However, the mechanism involving activation of HSCs in chronic schistosomiasis is not entirely clear. Human HSC LX-2 and human umbilical vein endothelial cells (ECs) were cultured with Schistosoma japonicum antigens (SA) in vitro. Fibrosis-associated genes and cell proliferation were analyzed. HSCs were isolated from mice of chronic schistosomiasis with or without praziquantel (PZQ) treatment, followed by the microarray analysis for the liver fibrosis-associated pathways. Although SA inhibited the activation and proliferation of HSCs, it induced the EC proliferation and vascular endothelial growth factor-a (VEGF) production. VEGF significantly increased the proliferation of HSCs and upregulated the expression of collagen and α-smooth muscle actin. For in vivo study, we found that several fibrosis-associated pathways were involved in the HSCs during the reversal of liver fibrosis caused by schistosomiasis, including VEGF, platelet-derived growth factor, tumor necrosis factor and endothelin-1 pathways. The Ingenuity Pathway Analysis showed that VEGF directly regulated several pro-fibrotic and immune cytokine genes in HSCs, including integrin, fibronectin, interferon-γ, interleukin (IL)-6 and IL-10. Our data indicated the critical role of VEGF signaling in HSC activation in chronic schistosomiasis and highlighted several promising genes and pathways in HSCs as potential targets for therapeutic treatment of liver fibrosis.
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- 2017
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8. Transcriptional Profiling in Experimental Visceral Leishmaniasis Reveals a Broad Splenic Inflammatory Environment that Conditions Macrophages toward a Disease-Promoting Phenotype.
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Kong F, Saldarriaga OA, Spratt H, Osorio EY, Travi BL, Luxon BA, and Melby PC
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- Animals, Cricetinae, Cytokines immunology, Disease Models, Animal, Female, Gene Expression Profiling, Gene Library, Humans, Inflammation, Leishmaniasis, Visceral immunology, Macrophage Activation, Macrophages immunology, Mesocricetus, Nitric Oxide metabolism, Phenotype, Sequence Analysis, RNA, Spleen immunology, Spleen parasitology, Up-Regulation, Gene Expression Regulation, Leishmania donovani genetics, Leishmaniasis, Visceral parasitology, Macrophages parasitology, Transcriptome
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Visceral Leishmaniasis (VL), caused by the intracellular protozoan Leishmania donovani, is characterized by relentlessly increasing visceral parasite replication, cachexia, massive splenomegaly, pancytopenia and ultimately death. Progressive disease is considered to be due to impaired effector T cell function and/or failure of macrophages to be activated to kill the intracellular parasite. In previous studies, we used the Syrian hamster (Mesocricetus auratus) as a model because it mimics the progressive nature of active human VL. We demonstrated previously that mixed expression of macrophage-activating (IFN-γ) and regulatory (IL-4, IL-10, IL-21) cytokines, parasite-induced expression of macrophage arginase 1 (Arg1), and decreased production of nitric oxide are key immunopathologic factors. Here we examined global changes in gene expression to define the splenic environment and phenotype of splenic macrophages during progressive VL. We used RNA sequencing coupled with de novo transcriptome assembly, because the Syrian hamster does not have a fully sequenced and annotated reference genome. Differentially expressed transcripts identified a highly inflammatory spleen environment with abundant expression of type I and type II interferon response genes. However, high IFN-γ expression was ineffective in directing exclusive M1 macrophage polarization, suppressing M2-associated gene expression, and restraining parasite replication and disease. While many IFN-inducible transcripts were upregulated in the infected spleen, fewer were induced in splenic macrophages in VL. Paradoxically, IFN-γ enhanced parasite growth and induced the counter-regulatory molecules Arg1, Ido1 and Irg1 in splenic macrophages. This was mediated, at least in part, through IFN-γ-induced activation of STAT3 and expression of IL-10, which suggests that splenic macrophages in VL are conditioned to respond to macrophage activation signals with a counter-regulatory response that is ineffective and even disease-promoting. Accordingly, inhibition of STAT3 activation led to a reduced parasite load in infected macrophages. Thus, the STAT3 pathway offers a rational target for adjunctive host-directed therapy to interrupt the pathogenesis of VL., Competing Interests: The authors have declared that no competing interests exist.
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- 2017
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9. Convergent transcriptomics and proteomics of environmental enrichment and cocaine identifies novel therapeutic strategies for addiction.
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Zhang Y, Crofton EJ, Fan X, Li D, Kong F, Sinha M, Luxon BA, Spratt HM, Lichti CF, and Green TA
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- Animals, Cocaine administration & dosage, Computational Biology, Disease Models, Animal, Dopamine Uptake Inhibitors administration & dosage, Nucleus Accumbens drug effects, Nucleus Accumbens metabolism, RNA, Messenger metabolism, Random Allocation, Rats, Sprague-Dawley, Self Administration, Social Isolation, Cocaine-Related Disorders metabolism, Cocaine-Related Disorders therapy, Environment, Proteome, Transcriptome
- Abstract
Transcriptomic and proteomic approaches have separately proven effective at identifying novel mechanisms affecting addiction-related behavior; however, it is difficult to prioritize the many promising leads from each approach. A convergent secondary analysis of proteomic and transcriptomic results can glean additional information to help prioritize promising leads. The current study is a secondary analysis of the convergence of recently published separate transcriptomic and proteomic analyses of nucleus accumbens (NAc) tissue from rats subjected to environmental enrichment vs. isolation and cocaine self-administration vs. saline. Multiple bioinformatics approaches (e.g. Gene Ontology (GO) analysis, Ingenuity Pathway Analysis (IPA), and Gene Set Enrichment Analysis (GSEA)) were used to interrogate these rich data sets. Although there was little correspondence between mRNA vs. protein at the individual target level, good correspondence was found at the level of gene/protein sets, particularly for the environmental enrichment manipulation. These data identify gene sets where there is a positive relationship between changes in mRNA and protein (e.g. glycolysis, ATP synthesis, translation elongation factor activity, etc.) and gene sets where there is an inverse relationship (e.g. ribosomes, Rho GTPase signaling, protein ubiquitination, etc.). Overall environmental enrichment produced better correspondence than cocaine self-administration. The individual targets contributing to mRNA and protein effects were largely not overlapping. As a whole, these results confirm that robust transcriptomic and proteomic data sets can provide similar results at the gene/protein set level even when there is little correspondence at the individual target level and little overlap in the targets contributing to the effects., (Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.)
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- 2016
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10. Differential inflammasome activation signatures following intracellular infection of human macrophages with Mycobacterium bovis BCG or Trypanosoma cruzi.
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Huante MB, Gupta S, Calderon VC, Koo SJ, Sinha M, Luxon BA, Garg NJ, and Endsley JJ
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- Apoptosis drug effects, Apoptosis Regulatory Proteins metabolism, Cell Line, Cytokines metabolism, Host-Pathogen Interactions, Humans, Immunity, Innate drug effects, Inflammasomes drug effects, Inflammasomes genetics, Inflammasomes immunology, Lipopolysaccharides pharmacology, Macrophages immunology, Macrophages metabolism, NLR Family, Pyrin Domain-Containing 3 Protein genetics, NLR Family, Pyrin Domain-Containing 3 Protein immunology, Signal Transduction drug effects, Time Factors, Toll-Like Receptors metabolism, Trypanosoma cruzi immunology, BCG Vaccine pharmacology, Inflammasomes metabolism, Macrophage Activation drug effects, Macrophages drug effects, Macrophages parasitology, NLR Family, Pyrin Domain-Containing 3 Protein metabolism, Trypanosoma cruzi pathogenicity
- Abstract
Pathogens frequently exploit or evade inflammasome activation in order to survive and proliferate. Alternatively, inadequate inflammasome activation by attenuated microorganisms or adjuvanted subunit vaccines may contribute to poor longevity of protection. To further understand these pathways, we determined the differential inflammasome transcriptome of human THP monocyte-derived macrophages in response to Mycobacterium bovis BCG, as compared to LPS or Trypanosoma cruzi. The results identify the highly specific innate recognition programs associated with inflammasome activation by human macrophages exposed to these microbial stimuli. BCG, T. cruzi, and LPS strongly induced expression of both unique and overlapping genes downstream of TLR signaling pathways including cytokines and chemokines that mediate inflammation and regulate cell death pathways. Compared to LPS, BCG failed to directly activate anti-apoptotic molecules and multiple NLR and inflammasome complex components including caspase-1, and actively repressed important signaling intermediates in AP-1 and NFκB transcription factor pathways. Both BCG and T. cruzi repressed expression of TXNIP, an anti-oxidant inhibitor that recruits caspase-1 to the NLRP3 inflammasome, while T. cruzi infection uniquely failed to activate TNF-α. These results identify unique pathogen specific strategies to activate inflammation and modulate cell death that may drive inflammatory outcomes and suggest avenues of investigation to optimize host immunity., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
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- 2016
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11. Transcriptomics of Environmental Enrichment Reveals a Role for Retinoic Acid Signaling in Addiction.
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Zhang Y, Kong F, Crofton EJ, Dragosljvich SN, Sinha M, Li D, Fan X, Koshy S, Hommel JD, Spratt HM, Luxon BA, and Green TA
- Abstract
There exists much variability in susceptibility/resilience to addiction in humans. The environmental enrichment paradigm is a rat model of resilience to addiction-like behavior, and understanding the molecular mechanisms underlying this protective phenotype may lead to novel targets for pharmacotherapeutics to treat cocaine addiction. We investigated the differential regulation of transcript levels using RNA sequencing of the rat nucleus accumbens after environmental enrichment/isolation and cocaine/saline self-administration. Ingenuity Pathways Analysis and Gene Set Enrichment Analysis of 14,309 transcripts demonstrated that many biofunctions and pathways were differentially regulated. New functional pathways were also identified for cocaine modulation (e.g., Rho GTPase signaling) and environmental enrichment (e.g., signaling of EIF2, mTOR, ephrin). However, one novel pathway stood out above the others, the retinoic acid (RA) signaling pathway. The RA signaling pathway was identified as one likely mediator of the protective enrichment addiction phenotype, an interesting result given that nine RA signaling-related genes are expressed selectively and at high levels in the nucleus accumbens shell (NAcSh). Subsequent knockdown of Cyp26b1 (an RA degradation enzyme) in the NAcSh of rats confirmed this role by increasing cocaine self-administration as well as cocaine seeking. These results provide a comprehensive account of enrichment effects on the transcriptome and identify RA signaling as a contributing factor for cocaine addiction.
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- 2016
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12. Medical co-morbidities of patients with haemophilia: pain, obesity and hepatitis C.
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Witkop ML, Peerlinck K, and Luxon BA
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- Antiviral Agents therapeutic use, Chronic Pain pathology, Factor VIII therapeutic use, Genotype, Hemophilia A diagnosis, Hepacivirus genetics, Hepatitis C diagnosis, Hepatitis C drug therapy, Hepatitis C virology, Humans, Joint Diseases complications, Liver Cirrhosis etiology, Obesity pathology, Chronic Pain complications, Hemophilia A complications, Hepatitis C complications, Obesity complications
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Clinical care of patients with haemophilia (PWH) has progressed rapidly over the past decade. Current therapy has allowed patients with haemophilia to live longer and many patients are now experiencing the co-morbidities of the general population. In this review article, we focus on three common diseases states that affect PWH: chronic pain, obesity and hepatitis C. Pain has been a co-morbidity for many years and PWH often have unusual needs for chronic pain relief compared to the general population. Obesity is not only increasing in the general population but also in patients with hereditary bleeding disorders. The co-morbidity of obesity not only causes increased pain progression and joint damage but also affects the dosing of factor concentrates. Finally, hepatitis C is known to have infected the majority of patients who received non-virally inactivated pooled factor concentrates in the past. New treatment regimens have been developed that allow the nearly uniform cure of chronic hepatitis C with a short course of oral medications., (© 2016 John Wiley & Sons Ltd.)
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- 2016
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13. Regulation of limited N-terminal proteolysis of APE1 in tumor via acetylation and its role in cell proliferation.
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Bhakat KK, Sengupta S, Adeniyi VF, Roychoudhury S, Nath S, Bellot LJ, Feng D, Mantha AK, Sinha M, Qiu S, and Luxon BA
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- Acetylation, Humans, Proteolysis, Tumor Cells, Cultured, Cell Proliferation physiology, DNA-(Apurinic or Apyrimidinic Site) Lyase metabolism, Gene Expression Regulation, Neoplastic physiology, Neoplasms metabolism, Neoplasms pathology
- Abstract
Mammalian apurinic/apyrimidinic (AP) endonuclease 1 (APE1), a ubiquitous and multifunctional protein, plays an essential role in the repair of both endogenous and drug-induced DNA damages in the genome. Unlike its E.coli counterpart Xth, mammalian APE1 has a unique N-terminal domain and possesses both DNA damage repair and transcriptional regulatory functions. Although the overexpression of APE1 in diverse cancer types and the association of APE1 expression with chemotherapy resistance and poor prognosis are well documented, the cellular and molecular mechanisms that alter APE1 functions during tumorigenesis are largely unknown. Here, we show the presence of full-length APE1 and N-terminal truncated isoforms of APE1 in tumor tissue samples of various cancer types. However, primary tumor tissue has higher levels of acetylated APE1 (AcAPE1) as well as full-length APE1 compared to adjacent non-tumor tissue. We found that APE1 is proteolytically cleaved by an unknown serine protease at its N-terminus following residue lysine (Lys) Lys6 and/or Lys7 and after Lys27 and Lys31 or Lys32. Acetylation of these Lys residues in APE1 prevents this proteolysis. The N-terminal domain of APE1 and its acetylation are required for modulation of the expression of hundreds of genes. Importantly, we found that AcAPE1 is essential for sustained cell proliferation. Together, our study demonstrates that increased acetylation levels of APE1 in tumor cells inhibit the limited N-terminal proteolysis of APE1 and thereby maintain the functions of APE1 to promote tumor cells' sustained proliferation and survival., Competing Interests: The authors disclose no potential conflicts of interest.
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- 2016
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14. Analysis of the TGFβ-induced program in primary airway epithelial cells shows essential role of NF-κB/RelA signaling network in type II epithelial mesenchymal transition.
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Tian B, Li X, Kalita M, Widen SG, Yang J, Bhavnani SK, Dang B, Kudlicki A, Sinha M, Kong F, Wood TG, Luxon BA, and Brasier AR
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- Epithelial Cells metabolism, High-Throughput Nucleotide Sequencing, Humans, Lung Neoplasms pathology, NF-kappa B genetics, Signal Transduction genetics, Stem Cells metabolism, Transcription Factor RelA metabolism, Transforming Growth Factor beta antagonists & inhibitors, Epithelial-Mesenchymal Transition genetics, Lung Neoplasms genetics, Transcription Factor RelA genetics, Transforming Growth Factor beta genetics
- Abstract
Background: The airway epithelial cell plays a central role in coordinating the pulmonary response to injury and inflammation. Here, transforming growth factor-β (TGFβ) activates gene expression programs to induce stem cell-like properties, inhibit expression of differentiated epithelial adhesion proteins and express mesenchymal contractile proteins. This process is known as epithelial mesenchymal transition (EMT); although much is known about the role of EMT in cellular metastasis in an oncogene-transformed cell, less is known about Type II EMT, that occurring in normal epithelial cells. In this study, we applied next generation sequencing (RNA-Seq) in primary human airway epithelial cells to understand the gene program controlling Type II EMT and how cytokine-induced inflammation modifies it., Results: Generalized linear modeling was performed on a two-factor RNA-Seq experiment of 6 treatments of telomerase immortalized human small airway epithelial cells (3 replicates). Using a stringent cut-off, we identified 3,478 differentially expressed genes (DEGs) in response to EMT. Unbiased transcription factor enrichment analysis identified three clusters of EMT regulators, one including SMADs/TP63 and another NF-κB/RelA. Surprisingly, we also observed 527 of the EMT DEGs were also regulated by the TNF-NF-κB/RelA pathway. This Type II EMT program was compared to Type III EMT in TGFβ stimulated A549 alveolar lung cancer cells, revealing significant functional differences. Moreover, we observe that Type II EMT modifies the outcome of the TNF program, reducing IFN signaling and enhancing integrin signaling. We confirmed experimentally that TGFβ-induced the NF-κB/RelA pathway by observing a 2-fold change in NF-κB/RelA nuclear translocation. A small molecule IKK inhibitor blocked TGFβ-induced core transcription factor (SNAIL1, ZEB1 and Twist1) and mesenchymal gene (FN1 and VIM) expression., Conclusions: These data indicate that NF-κB/RelA controls a SMAD-independent gene network whose regulation is required for initiation of Type II EMT. Type II EMT dramatically affects the induction and kinetics of TNF-dependent gene networks.
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- 2015
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15. Caspase-1/ASC inflammasome-mediated activation of IL-1β-ROS-NF-κB pathway for control of Trypanosoma cruzi replication and survival is dispensable in NLRP3-/- macrophages.
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Dey N, Sinha M, Gupta S, Gonzalez MN, Fang R, Endsley JJ, Luxon BA, and Garg NJ
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- Animals, Apoptosis Regulatory Proteins genetics, Apoptosis Regulatory Proteins metabolism, CARD Signaling Adaptor Proteins, Carrier Proteins genetics, Chagas Disease genetics, Cytoskeletal Proteins genetics, Cytoskeletal Proteins metabolism, Disease Models, Animal, Female, Gene Expression Profiling, Humans, Inflammasomes genetics, Macrophages parasitology, Mice, Mice, Knockout, NLR Family, Pyrin Domain-Containing 3 Protein, Caspase 1 metabolism, Chagas Disease metabolism, Chagas Disease parasitology, Inflammasomes metabolism, Interleukin-1beta metabolism, Macrophages metabolism, NF-kappa B metabolism, Reactive Oxygen Species metabolism, Signal Transduction, Trypanosoma cruzi
- Abstract
In this study, we have utilized wild-type (WT), ASC-/-, and NLRP3-/- macrophages and inhibition approaches to investigate the mechanisms of inflammasome activation and their role in Trypanosoma cruzi infection. We also probed human macrophages and analyzed published microarray datasets from human fibroblasts, and endothelial and smooth muscle cells for T. cruzi-induced changes in the expression genes included in the RT Profiler Human Inflammasome arrays. T. cruzi infection elicited a subdued and delayed activation of inflammasome-related gene expression and IL-1β production in mφs in comparison to LPS-treated controls. When WT and ASC-/- macrophages were treated with inhibitors of caspase-1, IL-1β, or NADPH oxidase, we found that IL-1β production by caspase-1/ASC inflammasome required reactive oxygen species (ROS) as a secondary signal. Moreover, IL-1β regulated NF-κB signaling of inflammatory cytokine gene expression and, subsequently, intracellular parasite replication in macrophages. NLRP3-/- macrophages, despite an inability to elicit IL-1β activation and inflammatory cytokine gene expression, exhibited a 4-fold decline in intracellular parasites in comparison to that noted in matched WT controls. NLRP3-/- macrophages were not refractory to T. cruzi, and instead exhibited a very high basal level of ROS (>100-fold higher than WT controls) that was maintained after infection in an IL-1β-independent manner and contributed to efficient parasite killing. We conclude that caspase-1/ASC inflammasomes play a significant role in the activation of IL-1β/ROS and NF-κB signaling of cytokine gene expression for T. cruzi control in human and mouse macrophages. However, NLRP3-mediated IL-1β/NFκB activation is dispensable and compensated for by ROS-mediated control of T. cruzi replication and survival in macrophages.
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- 2014
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16. Potential catalysts in therapeutics.
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Luxon BA
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- Diffusion of Innovation, Graft Rejection immunology, Humans, Immunosuppressive Agents adverse effects, Liver Transplantation adverse effects, Liver Transplantation trends, Time Factors, Treatment Outcome, Graft Rejection prevention & control, Graft Survival drug effects, Immunosuppressive Agents therapeutic use, Liver Transplantation methods
- Abstract
After years of expecting new advances in immunosuppression, we have not seen a newly developed drug in the past decade. Recent efforts have been centered on minimizing the known side effects of steroids and CNI. It is unlikely that a new CNI will be developed; however, extended-release tacrolimus is available. Most clinical research trials are designed to determine when and how to withdraw steroids or CNI, either substituting mTOR inhibitors or withdrawing an agent completely. As with CNI, there is little evidence that new mTOR inhibitors are in the “publicly viewable” pharmaceutical pipeline. New antibodies that block costimulatory pathways currently have been approved or are being studied in both kidney and liver transplantation (Fig. 14). Most studies are initially performed with other diseases requiring immune modulation such as RA or psoriasis psoriasis. Other blocking antibodies are being studied in kidney transplantation. It is unlikely that these newer agents will be generally available in the next 2 to 3 years. It seems likely that they may find specialized use in specific populations of patients (HCC or HCV infection) for whom the risk of side effects is adequately balanced by the beneficial effects of immunosuppression and prevention of infection or cancer progression.
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- 2014
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17. Environmental enrichment alters protein expression as well as the proteomic response to cocaine in rat nucleus accumbens.
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Lichti CF, Fan X, English RD, Zhang Y, Li D, Kong F, Sinha M, Andersen CR, Spratt H, Luxon BA, and Green TA
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Prior research demonstrated that environmental enrichment creates individual differences in behavior leading to a protective addiction phenotype in rats. Understanding the mechanisms underlying this phenotype will guide selection of targets for much-needed novel pharmacotherapeutics. The current study investigates differences in proteome expression in the nucleus accumbens of enriched and isolated rats and the proteomic response to cocaine self-administration using a liquid chromatography mass spectrometry (LCMS) technique to quantify 1917 proteins. Results of complementary Ingenuity Pathways Analyses (IPA) and gene set enrichment analyses (GSEA), both performed using protein quantitative data, demonstrate that cocaine increases vesicular transporters for dopamine and glutamate as well as increasing proteins in the RhoA pathway. Further, cocaine regulates proteins related to ERK, CREB and AKT signaling. Environmental enrichment altered expression of a large number of proteins implicated in a diverse number of neuronal functions (e.g., energy production, mRNA splicing, and ubiquitination), molecular cascades (e.g., protein kinases), psychiatric disorders (e.g., mood disorders), and neurodegenerative diseases (e.g., Huntington's and Alzheimer's diseases). Upregulation of energy metabolism components in EC rats was verified using RNA sequencing. Most of the biological functions and pathways listed above were also identified in the Cocaine X Enrichment interaction analysis, providing clear evidence that enriched and isolated rats respond quite differently to cocaine exposure. The overall impression of the current results is that enriched saline-administering rats have a unique proteomic complement compared to enriched cocaine-administering rats as well as saline and cocaine-taking isolated rats. These results identify possible mechanisms of the protective phenotype and provide fertile soil for developing novel pharmacotherapeutics. Proteomics data are available via ProteomeXchange with identifier PXD000990.
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- 2014
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18. Cognitive enhancing treatment with a PPARγ agonist normalizes dentate granule cell presynaptic function in Tg2576 APP mice.
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Nenov MN, Laezza F, Haidacher SJ, Zhao Y, Sadygov RG, Starkey JM, Spratt H, Luxon BA, Dineley KT, and Denner L
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- Amyloid beta-Protein Precursor genetics, Animals, Dentate Gyrus drug effects, Female, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Organ Culture Techniques, Presynaptic Terminals drug effects, Protein Interaction Maps drug effects, Protein Interaction Maps physiology, Protein Transport drug effects, Protein Transport physiology, Rosiglitazone, Dentate Gyrus physiology, Nootropic Agents pharmacology, PPAR gamma agonists, PPAR gamma physiology, Presynaptic Terminals physiology, Thiazolidinediones pharmacology
- Abstract
Hippocampal network hyperexcitability is considered an early indicator of Alzheimer's disease (AD) memory impairment. Some AD mouse models exhibit similar network phenotypes. In this study we focused on dentate gyrus (DG) granule cell spontaneous and evoked properties in 9-month-old Tg2576 mice that model AD amyloidosis and cognitive deficits. Using whole-cell patch-clamp recordings, we found that Tg2576 DG granule cells exhibited spontaneous EPSCs that were higher in frequency but not amplitude compared with wild-type mice, suggesting hyperactivity of DG granule cells via a presynaptic mechanism. Further support of a presynaptic mechanism was revealed by increased I-O relationships and probability of release in Tg2576 DG granule cells. Since we and others have shown that activation of the peroxisome proliferator-activated receptor gamma (PPARγ) axis improves hippocampal cognition in mouse models for AD as well as benefitting memory performance in some humans with early AD, we investigated how PPARγ agonism affected synaptic activity in Tg2576 DG. We found that PPARγ agonism normalized the I-O relationship of evoked EPSCs, frequency of spontaneous EPSCs, and probability of release that, in turn, correlated with selective expression of DG proteins essential for presynaptic SNARE function that are altered in patients with AD. These findings provide evidence that DG principal cells may contribute to early AD hippocampal network hyperexcitability via a presynaptic mechanism, and that hippocampal cognitive enhancement via PPARγ activation occurs through regulation of presynaptic vesicular proteins critical for proper glutamatergic neurotransmitter release, synaptic transmission, and short-term plasticity.
- Published
- 2014
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19. Metabolomics in asthma.
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Luxon BA
- Subjects
- Airway Obstruction diagnosis, Airway Obstruction immunology, Asthma diagnosis, Asthma immunology, Biomarkers analysis, Breath Tests methods, Bronchoalveolar Lavage Fluid chemistry, Bronchoscopy, Electronic Nose, Gas Chromatography-Mass Spectrometry, Humans, Inflammation diagnosis, Inflammation immunology, Inflammation metabolism, Magnetic Resonance Spectroscopy, Metabolomics instrumentation, Airway Obstruction metabolism, Asthma metabolism, Metabolomics methods
- Abstract
Asthma and airway inflammation are responses to infectious stimuli and the mechanisms of how they are mediated, whether by the innate or adaptive immune response systems, are complex and results in a broad spectrum of possible metabolic products. In principle, a syndrome such as asthma should have a characteristic temporal-spatial metabolic signature indicative of its current state and the constituents that caused it. Generally, the term metabolomics refers to the quantitative analysis of sets of small compounds from biological samples with molecular masses less than 1 kDa so unambiguous identification can be difficult and usually requires sophisticated instrumentation. The practical success of clinical metabolomics will largely hinge on a few key issues such as the ability to capture a readily available biofluid that can be analyzed to identify metabolite biomarkers with the required sensitivity and specificity in a cost-effective manner in a clinical setting. In this chapter, we review the current state of the metabolomics of asthma and airway inflammation with a focus on the different methods and instrumentation being used for the discovery of biomarkers in research and their future translation into the clinic as diagnostic aids for the choice of patient-specific therapies.
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- 2014
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20. So you want to be a hepatologist?
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Luxon BA
- Subjects
- Certification, Humans, Liver Transplantation education, Professional Competence, Education, Medical, Continuing trends, Gastroenterology education, Liver Diseases diagnosis, Liver Diseases therapy, Specialization trends
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- 2013
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21. Vaccines based on structure-based design provide protection against infectious diseases.
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Thomas S and Luxon BA
- Subjects
- Humans, Vaccines, Synthetic genetics, Vaccines, Synthetic immunology, Drug Design, Epitopes genetics, Epitopes immunology, Protein Engineering methods, Vaccines genetics, Vaccines immunology
- Abstract
Vaccines elicit immune responses, provide protection against microorganisms and are considered as one of the most successful medical interventions against infectious diseases. Vaccines can be produced using attenuated virus or bacteria, recombinant proteins, bacterial polysaccharides, carbohydrates or plasmid DNA. Conventional vaccines rely on the induction of immune responses against antigenic proteins to be effective. The genetic diversity of microorganisms, coupled with the high degree of sequence variability in antigenic proteins, presents a challenge to developing broadly effective conventional vaccines. The observation that whole protein antigens are not necessarily essential for inducing immunity has led to the emergence of a new branch of vaccine design termed 'structural vaccinology'. Structure-based vaccines are designed on the rationale that protective epitopes should be sufficient to induce immune responses and provide protection against pathogens. Recent studies demonstrated that designing structure-based vaccine candidates with multiple epitopes induce a higher immune response. As yet there are no commercial vaccines available based on structure-based design and most of the structure-based vaccine candidates are in the preclinical stages of development. This review focuses on recent advances in structure-based vaccine candidates and their application in providing protection against infectious diseases.
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- 2013
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22. Detection of structural and metabolic changes in traumatically injured hippocampus by quantitative differential proteomics.
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Wu P, Zhao Y, Haidacher SJ, Wang E, Parsley MO, Gao J, Sadygov RG, Starkey JM, Luxon BA, Spratt H, Dewitt DS, Prough DS, and Denner L
- Subjects
- Animals, Blotting, Western, Brain Injuries metabolism, Brain Injuries pathology, Chromatography, Liquid, Disease Models, Animal, Hippocampus metabolism, Hippocampus pathology, Male, Rats, Rats, Sprague-Dawley, Tandem Mass Spectrometry, Brain Injuries physiopathology, Calcineurin metabolism, Hippocampus physiopathology, Proteomics methods
- Abstract
Traumatic brain injury (TBI) is a complex and common problem resulting in the loss of cognitive function. In order to build a comprehensive knowledge base of the proteins that underlie these cognitive deficits, we employed unbiased quantitative mass spectrometry, proteomics, and bioinformatics to identify and quantify dysregulated proteins in the CA3 subregion of the hippocampus in the fluid percussion model of TBI in rats. Using stable isotope 18O-water differential labeling and multidimensional tandem liquid chromatography (LC)-MS/MS with high stringency statistical analyses and filtering, we identified and quantified 1002 common proteins, with 124 increased and 76 decreased. The ingenuity pathway analysis (IPA) bioinformatics tool identified that TBI had profound effects on downregulating global energy metabolism, including glycolysis, the Krebs cycle, and oxidative phosphorylation, as well as cellular structure and function. Widespread upregulation of actin-related cytoskeletal dynamics was also found. IPA indicated a common integrative signaling node, calcineurin B1 (CANB1, CaNBα, or PPP3R1), which was downregulated by TBI. Western blotting confirmed that the calcineurin regulatory subunit, CANB1, and its catalytic binding partner PP2BA, were decreased without changes in other calcineurin subunits. CANB1 plays a critical role in downregulated networks of calcium signaling and homeostasis through calmodulin and calmodulin-dependent kinase II to highly interconnected structural networks dominated by tubulins. This large-scale knowledge base lays the foundation for the identification of novel therapeutic targets for cognitive rescue in TBI.
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- 2013
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23. Innate immune tolerance and the role of kupffer cells in differential responses to interferon therapy among patients with HCV genotype 1 infection.
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Lau DT, Negash A, Chen J, Crochet N, Sinha M, Zhang Y, Guedj J, Holder S, Saito T, Lemon SM, Luxon BA, Perelson AS, and Gale M Jr
- Subjects
- Adult, Biopsy, Cells, Cultured, Female, Follow-Up Studies, Gene Expression Regulation, Genotype, Hepatitis C, Chronic genetics, Hepatitis C, Chronic immunology, Hepatocytes immunology, Hepatocytes metabolism, Hepatocytes virology, Humans, Immunity, Innate drug effects, Interferon Regulatory Factors biosynthesis, Interferon Regulatory Factors genetics, Interferon alpha-2, Kupffer Cells drug effects, Liver immunology, Liver pathology, Liver virology, Male, Middle Aged, Models, Theoretical, Recombinant Proteins therapeutic use, Viral Load, Young Adult, Hepacivirus genetics, Hepatitis C, Chronic drug therapy, Immune Tolerance drug effects, Immunity, Innate immunology, Interferon-alpha therapeutic use, Kupffer Cells immunology, RNA, Viral genetics
- Abstract
Background & Aims: In patients with hepatitis C virus (HCV) infection, interferon alfa (IFN-α) alters expression of IFN-stimulated genes (ISGs), but little is understood about factors that determine outcomes of therapy. We used a systems biology approach to evaluate the acute response of patients with chronic hepatitis C to IFN-α therapy., Methods: We collected liver biopsy samples from 8 treatment-naïve patients with chronic HCV genotype 1 infection at baseline and 24 hours after treatment with IFN-α-2a (10 MU subcutaneously). Blood samples were collected before and up to 48 hours after administration of IFN-α-2a to measure HCV RNA levels and for gene expression analysis. Patients then received pegylated IFN-α-2a and ribavirin on day 5 of the study; therapy continued for up to 48 weeks., Results: Based on the kinetics of HCV RNA during the first 12 weeks of therapy, 2 patients were rapid virologic responders, 4 were early virologic responders, and 2 did not respond to therapy (nonresponders). Nonresponders had high pretreatment levels of ISG expression in the liver but not in peripheral blood mononuclear cells. In responders, after administration of IFN-α, intrahepatic ISG expression increased significantly from baseline and was associated with a rapid phase 1 decrease in HCV. We identified distinct hepatic expression and tissue distribution patterns of ISGs that segregated with treatment outcome. Importantly, Kupffer cells were a local source of IFN that promoted basal expression of ISG in hepatocytes of nonresponders. This finding was validated in cultured THP1 human macrophages that expressed IFN-β after exposure to viable HCV 2a. When Huh7 K2040 and Huh7 L2198S hepatoma cells were incubated with IFN-α-2a, expression of ISGs peaked by 4 hours and decreased by 72 hours, associated with an increase in level of HCV RNA. This indicates that constitutive exposure to IFN causes hepatoma cells to become tolerant of ISG function., Conclusions: In patients with chronic HCV infection, IFN production by Kupffer cells might promote innate immune tolerance, characterized by a lack of response to IFN therapy. Strategies to disrupt the virus-host interactions that induce innate immune tolerance should improve therapy., (Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.)
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- 2013
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24. Cognitive enhancement with rosiglitazone links the hippocampal PPARγ and ERK MAPK signaling pathways.
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Denner LA, Rodriguez-Rivera J, Haidacher SJ, Jahrling JB, Carmical JR, Hernandez CM, Zhao Y, Sadygov RG, Starkey JM, Spratt H, Luxon BA, Wood TG, and Dineley KT
- Subjects
- Amyloid beta-Peptides metabolism, Animals, Blotting, Western, Cell Nucleus physiology, Conditioning, Psychological, Electroshock, Fear, Female, Injections, Intraventricular, MAP Kinase Signaling System drug effects, Male, Mice, Mice, Inbred C57BL, PPAR gamma antagonists & inhibitors, Polymerase Chain Reaction, Rosiglitazone, Tandem Mass Spectrometry, Transcriptome physiology, Hippocampus physiology, MAP Kinase Signaling System physiology, Nootropic Agents pharmacology, PPAR gamma physiology, Signal Transduction physiology, Thiazolidinediones pharmacology
- Abstract
We previously reported that the peroxisome proliferator-activated receptor γ (PPARγ) agonist rosiglitazone (RSG) improved hippocampus-dependent cognition in the Alzheimer's disease (AD) mouse model, Tg2576. RSG had no effect on wild-type littermate cognitive performance. Since extracellular signal-regulated protein kinase mitogen-activated protein kinase (ERK MAPK) is required for many forms of learning and memory that are affected in AD, and since both PPARγ and ERK MAPK are key mediators of insulin signaling, the current study tested the hypothesis that RSG-mediated cognitive improvement induces a hippocampal PPARγ pattern of gene and protein expression that converges with the ERK MAPK signaling axis in Tg2576 AD mice. In the hippocampal PPARγ transcriptome, we found significant overlap between peroxisome proliferator response element-containing PPARγ target genes and ERK-regulated, cAMP response element-containing target genes. Within the Tg2576 dentate gyrus proteome, RSG induced proteins with structural, energy, biosynthesis and plasticity functions. Several of these proteins are known to be important for cognitive function and are also regulated by ERK MAPK. In addition, we found the RSG-mediated augmentation of PPARγ and ERK2 activity during Tg2576 cognitive enhancement was reversed when hippocampal PPARγ was pharmacologically antagonized, revealing a coordinate relationship between PPARγ transcriptional competency and phosphorylated ERK that is reciprocally affected in response to chronic activation, compared with acute inhibition, of PPARγ. We conclude that the hippocampal transcriptome and proteome induced by cognitive enhancement with RSG harnesses a dysregulated ERK MAPK signal transduction pathway to overcome AD-like cognitive deficits in Tg2576 mice. Thus, PPARγ represents a signaling system that is not crucial for normal cognition yet can intercede to restore neural networks compromised by AD.
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- 2012
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25. 1H Nuclear Magnetic Resonance (NMR) Metabolomic Study of Chronic Organophosphate Exposure in Rats.
- Author
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Alam TM, Neerathilingam M, Alam MK, Volk DE, Ansari GA, Sarkar S, and Luxon BA
- Abstract
1H NMR spectroscopy and chemometric analysis were used to characterize rat urine obtained after chronic exposure to either tributyl phosphate (TBP) or triphenyl phosphate (TPP). In this study, the daily dose exposure was 1.5 mg/kg body weight for TBP, or 2.0 mg/kg body weight for TPP, administered over a 15-week period. Orthogonal signal correction (OSC) -filtered partial least square discriminant analysis (OSC-PLSDA) was used to predict and classify exposure to these organophosphates. During the development of the model, the classification error was evaluated as a function of the number of latent variables. NMR spectral regions and corresponding metabolites important for determination of exposure type were identified using variable importance in projection (VIP) coefficients obtained from the OSC-PLSDA analysis. As expected, the model for classification of chronic (1.5-2.0 mg/kg body weight daily) TBP or TPP exposure was not as strong as the previously reported model developed for identifying acute (15-20 mg/kg body weight) exposure. The set of majorly impacted metabolites identified for chronic TBP or TPP exposure was slightly different than those metabolites previously identified for acute exposure. These metabolites were then mapped to different metabolite pathways and ranked, allowing the metabolic response to chronic organophosphate exposure to be addressed.
- Published
- 2012
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26. Proteomics improves the prediction of burns mortality: results from regression spline modeling.
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Finnerty CC, Ju H, Spratt H, Victor S, Jeschke MG, Hegde S, Bhavnani SK, Luxon BA, Brasier AR, and Herndon DN
- Subjects
- Burns blood, Child, Discriminant Analysis, Female, Humans, Male, Multivariate Analysis, Principal Component Analysis, Prognosis, ROC Curve, Reference Standards, Regression Analysis, Survival Analysis, Burns metabolism, Burns mortality, Models, Biological, Proteomics methods
- Abstract
Prediction of mortality in severely burned patients remains unreliable. Although clinical covariates and plasma protein abundance have been used with varying degrees of success, the triad of burn size, inhalation injury, and age remains the most reliable predictor. We investigated the effect of combining proteomics variables with these three clinical covariates on prediction of mortality in burned children. Serum samples were collected from 330 burned children (burns covering >25% of the total body surface area) between admission and the time of the first operation for clinical chemistry analyses and proteomic assays of cytokines. Principal component analysis revealed that serum protein abundance and the clinical covariates each provided independent information regarding patient survival. To determine whether combining proteomics with clinical variables improves prediction of patient mortality, we used multivariate adaptive regression splines, because the relationships between analytes and mortality were not linear. Combining these factors increased overall outcome prediction accuracy from 52% to 81% and area under the receiver operating characteristic curve from 0.82 to 0.95. Thus, the predictive accuracy of burns mortality is substantially improved by combining protein abundance information with clinical covariates in a multivariate adaptive regression splines classifier, a model currently being validated in a prospective study., (© 2012 Wiley Periodicals, Inc.)
- Published
- 2012
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27. The National NeuroAIDS Tissue Consortium brain gene array: two types of HIV-associated neurocognitive impairment.
- Author
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Gelman BB, Chen T, Lisinicchia JG, Soukup VM, Carmical JR, Starkey JM, Masliah E, Commins DL, Brandt D, Grant I, Singer EJ, Levine AJ, Miller J, Winkler JM, Fox HS, Luxon BA, and Morgello S
- Subjects
- Antigens, CD genetics, Antigens, Differentiation, Myelomonocytic genetics, HIV-1 pathogenicity, Humans, Receptors, Cell Surface genetics, Viral Load, Brain metabolism, HIV Infections physiopathology
- Abstract
Background: The National NeuroAIDS Tissue Consortium (NNTC) performed a brain gene expression array to elucidate pathophysiologies of Human Immunodeficiency Virus type 1 (HIV-1)-associated neurocognitive disorders., Methods: Twenty-four human subjects in four groups were examined A) Uninfected controls; B) HIV-1 infected subjects with no substantial neurocognitive impairment (NCI); C) Infected with substantial NCI without HIV encephalitis (HIVE); D) Infected with substantial NCI and HIVE. RNA from neocortex, white matter, and neostriatum was processed with the Affymetrix® array platform., Results: With HIVE the HIV-1 RNA load in brain tissue was three log(10) units higher than other groups and over 1,900 gene probes were regulated. Interferon response genes (IFRGs), antigen presentation, complement components and CD163 antigen were strongly upregulated. In frontal neocortex downregulated neuronal pathways strongly dominated in HIVE, including GABA receptors, glutamate signaling, synaptic potentiation, axon guidance, clathrin-mediated endocytosis and 14-3-3 protein. Expression was completely different in neuropsychologically impaired subjects without HIVE. They had low brain HIV-1 loads, weak brain immune responses, lacked neuronally expressed changes in neocortex and exhibited upregulation of endothelial cell type transcripts. HIV-1-infected subjects with normal neuropsychological test results had upregulation of neuronal transcripts involved in synaptic transmission of neostriatal circuits., Interpretation: Two patterns of brain gene expression suggest that more than one pathophysiological process occurs in HIV-1-associated neurocognitive impairment. Expression in HIVE suggests that lowering brain HIV-1 replication might improve NCI, whereas NCI without HIVE may not respond in kind; array results suggest that modulation of transvascular signaling is a potentially promising approach. Striking brain regional differences highlighted the likely importance of circuit level disturbances in HIV/AIDS. In subjects without impairment regulation of genes that drive neostriatal synaptic plasticity reflects adaptation. The array provides an infusion of public resources including brain samples, clinicopathological data and correlative gene expression data for further exploration (http://www.nntc.org/gene-array-project).
- Published
- 2012
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28. Effects of progesterone treatment on expression of genes involved in uterine quiescence.
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Soloff MS, Jeng YJ, Izban MG, Sinha M, Luxon BA, Stamnes SJ, and England SK
- Subjects
- Cell Line, Female, Gene Expression Profiling methods, Humans, Myometrium cytology, Myometrium physiology, Oligonucleotide Array Sequence Analysis, Pregnancy, Progesterone physiology, RNA chemistry, RNA genetics, Reverse Transcriptase Polymerase Chain Reaction, Transcription, Genetic physiology, Uterine Contraction genetics, Uterine Contraction physiology, Myometrium drug effects, Progesterone pharmacology, Transcription, Genetic drug effects, Uterine Contraction drug effects
- Abstract
An important action of progesterone during pregnancy is to maintain the uterus in a quiescent state and thereby prevent preterm labor. The causes of preterm labor are not well understood, so progesterone action on the myometrium can provide clues about the processes that keep the uterus from contracting prematurely. Accordingly, we have carried out Affymetrix GeneChip analysis of progesterone effects on gene expression in immortalized human myometrial cells cultured from a patient near the end of pregnancy. Progesterone appears to inhibit uterine excitability by a number of mechanisms, including increased expression of calcium and voltage-operated K(+) channels, which dampens the electrical activity of the myometrial cell, downregulation of agents, and receptors involved in myometrial contraction, reduction in cell signal components that lead to increased intracellular Ca(2+) concentrations in response to contractile stimuli, and downregulation of proteins involved in the cross-linking of actin and myosin filaments to produce uterine contractions.
- Published
- 2011
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29. Bone disorders in chronic liver diseases.
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Luxon BA
- Subjects
- Bone Density, Bone Diseases, Metabolic diagnosis, Bone Diseases, Metabolic epidemiology, Bone Diseases, Metabolic therapy, Chronic Disease, Humans, Liver Cirrhosis complications, Osteomalacia complications, Osteomalacia diagnosis, Osteomalacia epidemiology, Osteomalacia therapy, Osteoporosis complications, Osteoporosis diagnosis, Osteoporosis epidemiology, Osteoporosis therapy, Osteoporotic Fractures complications, Osteoporotic Fractures epidemiology, Prevalence, Risk Factors, Bone Diseases, Metabolic complications, Liver Diseases complications
- Abstract
Bone disease is a major complication of chronic liver disease. Osteomalacia is quite uncommon despite low vitamin D levels in the majority of patients with cirrhosis. In contrast, osteoporosis is quite common, occurring in up to 50% of patients. Osteoporosis can result in spontaneous or low-impact fractures in patients with chronic liver diseases, adversely affecting morbidity, quality of life, and survival. The general biology of osteoporosis, including its pathogenesis, diagnostic tools, and rationale for treatment, have been determined largely empirically from studies of postmenopausal women with osteoporosis. Treatment regimens with modification of risk factors, use of vitamin D, and supplementation with calcium and bisphosphonates have been shown to be effective in select groups of patients with chronic liver diseases.
- Published
- 2011
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30. Structure-based vaccines provide protection in a mouse model of ehrlichiosis.
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Thomas S, Thirumalapura NR, Crocquet-Valdes PA, Luxon BA, and Walker DH
- Subjects
- Amino Acid Sequence, Animals, Antibodies, Bacterial blood, Antibodies, Bacterial immunology, Antigens, Bacterial genetics, Antigens, Bacterial immunology, Bacterial Outer Membrane Proteins chemistry, Bacterial Outer Membrane Proteins genetics, CD4-Positive T-Lymphocytes immunology, Chaperonin 60 chemistry, Chaperonin 60 genetics, Ehrlichia genetics, Ehrlichia metabolism, Ehrlichiosis immunology, Ehrlichiosis microbiology, Female, Mice, Mice, Inbred C57BL, Molecular Sequence Data, Peptide Fragments immunology, Peptide Fragments metabolism, Protein Conformation, Th1 Cells immunology, Bacterial Outer Membrane Proteins immunology, Bacterial Vaccines chemistry, Bacterial Vaccines therapeutic use, Chaperonin 60 immunology, Ehrlichia immunology, Ehrlichiosis prevention & control
- Abstract
Background: Recent advances in bioinformatics have made it possible to predict the B cell and T cell epitopes of antigenic proteins. This has led to design of peptide based vaccines that are more specific, safe, and easy to produce. The obligately intracellular gram negative bacteria Ehrlichia cause ehrlichioses in humans and animals. As yet there are no vaccines to protect against Ehrlichia infection., Methodology/principal Findings: We applied the principle of structural vaccinology to design peptides to the epitopes of Ehrlichia muris outer membrane P28-19 (OMP-1/P28) and Ehrlichia Heat shock protein 60 (Hsp60/GroEL) antigenic proteins. Both P28-19 and Ehrlichia Hsp60 peptides reacted with polyclonal antibodies against E. canis and E. chaffeensis and could be used as a diagnostic tool for ehrlichiosis. In addition, we demonstrated that mice vaccinated with Ehrlichia P28-19 and Hsp60 peptides and later challenged with E. muris were protected against the pathogen., Conclusions/significance: Our results demonstrate the power of structural vaccines and could be a new strategy in the development of vaccines to provide protection against pathogenic microorganisms.
- Published
- 2011
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31. Biliverdin inhibits hepatitis C virus nonstructural 3/4A protease activity: mechanism for the antiviral effects of heme oxygenase?
- Author
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Zhu Z, Wilson AT, Luxon BA, Brown KE, Mathahs MM, Bandyopadhyay S, McCaffrey AP, and Schmidt WN
- Subjects
- Cell Line, Tumor, Heme Oxygenase-1 pharmacology, Hepacivirus drug effects, Humans, Kinetics, Serine Proteinase Inhibitors, Viral Nonstructural Proteins antagonists & inhibitors, Virus Replication drug effects, Antiviral Agents pharmacology, Biliverdine pharmacology, Peptide Hydrolases metabolism, Protease Inhibitors pharmacology
- Abstract
Unlabelled: Induction of heme oxygenase-1 (HO-1) inhibits hepatitis C virus (HCV) replication. Of the products of the reaction catalyzed by HO-1, iron has been shown to inhibit HCV ribonucleic acid (RNA) polymerase, but little is known about the antiviral activity of biliverdin (BV). Herein, we report that BV inhibits viral replication and viral protein expression in a dose-dependent manner in replicons and cells harboring the infectious J6/JFH construct. Using the SensoLyte 620 HCV Protease Assay with a wide wavelength excitation/emission (591 nm/622 nm) fluorescence energy transfer peptide, we found that both recombinant and endogenous nonstructural 3/4A (NS3/4A) protease from replicon microsomes are potently inhibited by BV. Of the tetrapyrroles tested, BV was the strongest inhibitor of NS3/4A activity, with a median inhibitory concentration (IC(50)) of 9 μM, similar to that of the commercial inhibitor, AnaSpec (Fremont, CA) #25346 (IC(50) 5 μM). Lineweaver-Burk plots indicated mixed competitive and noncompetitive inhibition of the protease by BV. In contrast, the effects of bilirubin (BR) on HCV replication and NS3/4A were much less potent. Because BV is rapidly converted to BR by biliverdin reductase (BVR) intracellularly, the effect of BVR knockdown on BV antiviral activity was assessed. After greater than 80% silencing of BVR, inhibition of viral replication by BV was enhanced. BV also increased the antiviral activity of α-interferon in replicons., Conclusion: BV is a potent inhibitor of HCV NS3/4A protease, which likely contributes to the antiviral activity of HO-1. These findings suggest that BV or its derivatives may be useful in future drug therapies targeting the NS3/4A protease., (Copyright © 2010 American Association for the Study of Liver Diseases.)
- Published
- 2010
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32. 1H NMR-based metabonomic investigation of tributyl phosphate exposure in rats.
- Author
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Neerathilingam M, Volk DE, Sarkar S, Alam TM, Alam MK, Ansari GA, and Luxon BA
- Subjects
- Animals, Biomarkers metabolism, Citric Acid Cycle drug effects, Citric Acid Cycle physiology, Environmental Pollutants pharmacokinetics, Male, Organophosphates pharmacokinetics, Protons, Radiation-Protective Agents pharmacokinetics, Rats, Rats, Sprague-Dawley, Urine chemistry, Environmental Pollutants toxicity, Magnetic Resonance Spectroscopy methods, Metabolomics methods, Organophosphates toxicity, Radiation-Protective Agents toxicity
- Abstract
Tributyl phosphate (TBP) is a toxic organophosphorous compound widely used in many industrial applications, including significant usage in nuclear processing. The industrial application of this chemical is responsible for occupational exposure and environmental pollution. In this study, (1)H NMR-based metabonomics has been applied to investigate the metabolic response to TBP exposure. Male Sprague-Dawley rats were given a TBP-dose of 15 mg/kg body weight, followed by 24h urine collection, as was previously demonstrated for finding most of the intermediates of TBP. High-resolution (1)H NMR spectroscopy of urine samples in conjunction with statistical pattern recognition and compound identification allowed for the metabolic changes associated with TBP treatment to be identified. Discerning NMR spectral regions corresponding to three TBP metabolites, dibutyl phosphate (DBP), N-acetyl-(S-3-hydroxybutyl)-L-cysteine and N-acetyl-(S-3-oxobutyl)-L-cysteine, were identified in TBP-treated rats. In addition, the (1)H NMR spectra revealed TBP-induced variations of endogenous urinary metabolites including benzoate, urea, and trigonelline along with metabolites involved in the Krebs cycle including citrate, cis-aconitate, trans-aconitate, 2-oxoglutarate, succinate, and fumarate. These findings indicate that TBP induces a disturbance to the Krebs cycle energy metabolism and provides a biomarker signature of TBP exposure. We show that three metabolites of TBP, dibutylphosphate, N-acetyl-(S-3-hydroxybutyl)-L-cysteine and N-acetyl-(S-3-oxobutyl)-L-cysteine, which are not present in the control groups, are the most important factors in separating the TBP and control groups (p<0.0023), while the endogenous compounds 2-oxoglutarate, benzoate, fumarate, trigonelline, and cis-aconetate were also important (p<0.01)., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2010
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33. ¹H and ³¹P NMR lipidome of ethanol-induced fatty liver.
- Author
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Fernando H, Kondraganti S, Bhopale KK, Volk DE, Neerathilingam M, Kaphalia BS, Luxon BA, Boor PJ, and Shakeel Ansari GA
- Subjects
- Alanine Transaminase blood, Animals, Aspartate Aminotransferases blood, Body Weight drug effects, Central Nervous System Depressants pharmacology, Chemical and Drug Induced Liver Injury pathology, Cluster Analysis, Data Interpretation, Statistical, Ethanol pharmacology, Fatty Liver, Alcoholic pathology, Immunohistochemistry, Lipids blood, Liver drug effects, Liver pathology, Magnetic Resonance Spectroscopy, Male, Organ Size drug effects, Oxidative Stress physiology, Phosphorus Isotopes, Principal Component Analysis, Protons, Rats, Rats, Inbred F344, Fatty Liver, Alcoholic metabolism, Lipid Metabolism drug effects
- Abstract
Background: Hepatic steatosis (fatty liver), an early and reversible stage of alcoholic liver disease, is characterized by triglyceride deposition in hepatocytes, which can advance to steatohepatitis, fibrosis, cirrhosis, and ultimately to hepatocellular carcinoma. In the present work, we studied altered plasma and hepatic lipid metabolome (lipidome) to understand the mechanisms and lipid pattern of early-stage alcohol-induced-fatty liver., Methods: Male Fischer 344 rats were fed 5% alcohol in a Lieber-DeCarli diet. Control rats were pair-fed an equivalent amount of maltose-dextrin. After 1 month, animals were killed and plasma collected. Livers were excised for morphological, immunohistochemical, and biochemical studies. The lipids from plasma and livers were extracted with methyl-tert-butyl ether and analyzed by 750/800 MHz proton nuclear magnetic resonance (¹H NMR) and phosphorus (³¹P) NMR spectroscopy on a 600 MHz spectrometer. The NMR data were then subjected to multivariate statistical analysis., Results: Hematoxylin and Eosin and Oil Red O stained liver sections showed significant fatty infiltration. Immunohistochemical analysis of liver sections from ethanol-fed rats showed no inflammation (absence of CD3 positive cells) or oxidative stress (absence of malondialdehyde reactivity or 4-hydroxynonenal positive staining). Cluster analysis and principal component analysis of ¹H NMR data of lipid extracts of both plasma and livers showed a significant difference in the lipid metabolome of ethanol-fed versus control rats. ³¹P NMR data of liver lipid extracts showed significant changes in phospholipids similar to ¹H NMR data. ¹H NMR data of plasma and liver reflected several changes, while comparison of ¹H NMR and ³¹P NMR data offered a correlation among the phospholipids., Conclusions: Our results show that alcohol consumption alters metabolism of cholesterol, triglycerides, and phospholipids that could contribute to the development of fatty liver. These studies also indicate that fatty liver precedes oxidative stress and inflammation. The similarities observed in plasma and liver lipid profiles offer a potential methodology for detecting early-stage alcohol-induced fatty liver disease by analyzing the plasma lipid profile., (Copyright © 2010 by the Research Society on Alcoholism.)
- Published
- 2010
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34. Altered retinoic acid metabolism in diabetic mouse kidney identified by O isotopic labeling and 2D mass spectrometry.
- Author
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Starkey JM, Zhao Y, Sadygov RG, Haidacher SJ, Lejeune WS, Dey N, Luxon BA, Kane MA, Napoli JL, Denner L, and Tilton RG
- Subjects
- Animals, Blotting, Western, Chromatography, High Pressure Liquid methods, Male, Mice, Mice, Inbred C57BL, Microscopy, Fluorescence, Oxygen Isotopes, Reverse Transcriptase Polymerase Chain Reaction, Diabetes Mellitus, Experimental metabolism, Kidney metabolism, Mass Spectrometry methods, Tretinoin metabolism
- Abstract
Background: Numerous metabolic pathways have been implicated in diabetes-induced renal injury, yet few studies have utilized unbiased systems biology approaches for mapping the interconnectivity of diabetes-dysregulated proteins that are involved. We utilized a global, quantitative, differential proteomic approach to identify a novel retinoic acid hub in renal cortical protein networks dysregulated by type 2 diabetes., Methodology/principal Findings: Total proteins were extracted from renal cortex of control and db/db mice at 20 weeks of age (after 12 weeks of hyperglycemia in the diabetic mice). Following trypsinization, (18)O- and (16)O-labeled control and diabetic peptides, respectively, were pooled and separated by two dimensional liquid chromatography (strong cation exchange creating 60 fractions further separated by nano-HPLC), followed by peptide identification and quantification using mass spectrometry. Proteomic analysis identified 53 proteins with fold change >or=1.5 and p
- Published
- 2010
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35. Pathway signature and cellular differentiation in clear cell renal cell carcinoma.
- Author
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Tun HW, Marlow LA, von Roemeling CA, Cooper SJ, Kreinest P, Wu K, Luxon BA, Sinha M, Anastasiadis PZ, and Copland JA
- Subjects
- Adipogenesis genetics, Biomarkers, Tumor metabolism, Carcinoma, Renal Cell pathology, Cell Transdifferentiation genetics, Epithelium metabolism, Epithelium pathology, Gene Expression Regulation, Neoplastic, Humans, Kidney metabolism, Kidney pathology, Kidney Neoplasms pathology, Mesoderm metabolism, Mesoderm pathology, Models, Biological, Osteogenesis genetics, Reproducibility of Results, Transcription Factors metabolism, Carcinoma, Renal Cell genetics, Cell Differentiation genetics, Kidney Neoplasms genetics, Signal Transduction genetics
- Abstract
Background: Clear cell renal cell carcinoma (ccRCC) is the most common kidney cancer. The purpose of this study is to define a biological pathway signature and a cellular differentiation program in ccRCC., Methodology: We performed gene expression profiling of early-stage ccRCC and patient-matched normal renal tissue using Affymetrix HG-U133a and HG-U133b GeneChips combined with a comprehensive bioinformatic analyses, including pathway analysis. The results were validated by real time PCR and IHC on two independent sample sets. Cellular differentiation experiments were performed on ccRCC cell lines and their matched normal renal epithelial cells, in differentiation media, to determine their mesenchymal differentiation potential., Principal Findings: We identified a unique pathway signature with three major biological alterations-loss of normal renal function, down-regulated metabolism, and immune activation-which revealed an adipogenic gene expression signature linked to the hallmark lipid-laden clear cell morphology of ccRCC. Culturing normal renal and ccRCC cells in differentiation media showed that only ccRCC cells were induced to undergo adipogenic and, surprisingly, osteogenic differentiation. A gene expression signature consistent with epithelial mesenchymal transition (EMT) was identified for ccRCC. We revealed significant down-regulation of four developmental transcription factors (GATA3, TFCP2L1, TFAP2B, DMRT2) that are important for normal renal development., Conclusions: ccRCC is characterized by a lack of epithelial differentiation, mesenchymal/adipogenic transdifferentiation, and pluripotent mesenchymal stem cell-like differentiation capacity in vitro. We suggest that down-regulation of developmental transcription factors may mediate the aberrant differentiation in ccRCC. We propose a model in which normal renal epithelial cells undergo dedifferentiation, EMT, and adipogenic transdifferentiation, resulting in ccRCC. Because ccRCC cells grown in adipogenic media regain the characteristic ccRCC phenotype, we have identified a new in vitro ccRCC cell model more resembling ccRCC tumor morphology.
- Published
- 2010
- Full Text
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36. Training for a career in hepatology: which path to take?
- Author
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Luxon BA
- Subjects
- Humans, Career Choice, Education, Medical, Graduate organization & administration, Gastroenterology education, Gastroenterology organization & administration, Liver Transplantation
- Abstract
Hepatology has matured significantly over the past two decades, and most gastroenterologists now believe that it is a distinct subspecialty. An unmet public health need exists for professional expertise in the care of patients with liver diseases. However, our current training programs are struggling to adequately recruit and train physicians with the appropriate expertise in advanced and transplant hepatology. This review briefly summarizes the recent discoveries and developments in clinical hepatology, describes the past and current training paradigms, and suggests potential pathways to improve the number and quality of physicians trained in advanced and transplant hepatology.
- Published
- 2010
- Full Text
- View/download PDF
37. Hepatitis C virus core protein enhances Telomerase activity in Huh7 cells.
- Author
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Zhu Z, Wilson AT, Gopalakrishna K, Brown KE, Luxon BA, and Schmidt WN
- Subjects
- Artificial Gene Fusion, Cell Line, Tumor, Cell Nucleus chemistry, Gene Expression Profiling, Genes, Reporter, Humans, In Situ Hybridization, Fluorescence methods, Luciferases biosynthesis, Luciferases genetics, Telomere genetics, Up-Regulation, Hepacivirus pathogenicity, Hepatocytes virology, Host-Pathogen Interactions, Telomerase biosynthesis, Viral Core Proteins metabolism
- Abstract
Hepatitis C is an oncogenic virus although the mechanisms responsible for this behavior are not clear. We studied the effects of hepatitis C virus (HCV) core protein expression on Telomerase, an enzyme closely associated with cellular immortalization and neoplasia. The aim of this study was to investigate the effects of HCV core protein on the regulation of Telomerase activity in human hepatoma cells. Regulation and expression of human Telomerase reverse transcriptase (TERT) was compared in Huh7 cells stably transfected with HCV core protein or cells expressing vector alone. Telomerase activity was measured using Quantitative Telomerase Detection (QTD) and telomere length was measured by fluorescence in situ hybridization (FISH). Transient transfection and luciferase assay were used to evaluate TERT promoter activity. Telomerase activity was increased twofold in Huh7 cells expressing HCV core protein compared to controls (P < 0.01). This was accompanied by a 1.4-fold increase of TERT mRNA and 1.9-fold increase in TERT protein (P < 0.01 in either case). Cellular fractionation and immunocytochemical studies showed increased localization of TERT in the nucleus of core-expressing cells as compared to controls. FISH assay confirmed that telomeres of HCV core-expressing Huh7 cells were relatively longer than those of control cells (0.22 + 0.05 vs. 0.12 + 0.03, P < 0.01). TERT promoter activity was enhanced about 30% in HCV core-expressing Huh7 cells compared to control cells (P < 0.02). HCV core protein is associated with increased Telomerase activity in hepatoma cells. These findings suggest that enhancement of Telomerase activity by HCV core protein may contribute to the oncogenicity of HCV., ((c) 2009 Wiley-Liss, Inc.)
- Published
- 2010
- Full Text
- View/download PDF
38. Attenuated and lethal variants of Pichindé virus induce differential patterns of NF-kappaB activation suggesting a potential target for novel therapeutics.
- Author
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Bowick GC, Fennewald SM, Zhang L, Yang X, Aronson JF, Shope RE, Luxon BA, Gorenstein DG, and Herzog NK
- Subjects
- Animals, CSK Tyrosine-Protein Kinase, Defective Viruses physiology, Drug Delivery Systems, In Vitro Techniques, Mice, NF-kappa B p50 Subunit metabolism, Phosphorylation, Pichinde virus physiology, Protein Processing, Post-Translational, Protein Transport, Protein-Tyrosine Kinases metabolism, Signal Transduction, Transcription Factor RelA metabolism, Transcription, Genetic, Virulence, src-Family Kinases, Arenaviridae Infections drug therapy, Defective Viruses pathogenicity, Monocytes virology, NF-kappa B metabolism, Pichinde virus pathogenicity
- Abstract
Lassa virus pathogenesis is believed to involve dysregulation of cytokines. We have previously shown nuclear factor-kappaB (NF-kappaB) inhibition using a BSL-2 model for Lassa fever. Here we further define the potential mechanism for NF-kappaB inhibition as involving increased levels of repressive p50/p50 homodimers, and suggest a novel therapeutic strategy that acts via modulation of host signaling.
- Published
- 2009
- Full Text
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39. Global transcription profiling and virulence potential of Streptococcus pneumoniae after serial passage.
- Author
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Pandya U, Sinha M, Luxon BA, Watson DA, and Niesel DW
- Subjects
- Animals, Culture Techniques, Female, Mice, Oligonucleotide Array Sequence Analysis, Streptococcus pneumoniae pathogenicity, Virulence, Gene Expression Profiling, Streptococcus pneumoniae genetics, Streptococcus pneumoniae growth & development, Virulence Factors genetics
- Abstract
Streptococcus pneumoniae, a facultative human pathogen associated with wide variety of diseases, such as pneumonia, meningitis, sepsis and otitis media. Factors involved in the initial colonization, survival and etiology of this commensal bacteria in the human host from the ex vivo environment is still not clearly understood. Here, we report alterations in global transcriptional profiles of S. pneumoniae 6304 serotype 4 after 50 passages (50P) and 100 passages (100P) on laboratory media to better understand gene expression strategies employed by the bacterium during progression from the nasopharynx to the blood. The results show that six-fold more genes were differentially expressed after 100P as compared to 50P. After 100P on blood agar plates, 726 genes (33%) of 2192 genes in the S. pneumoniae genome were differentially expressed. Moreover, the majority of these genes (68%) were expressed at higher levels with increasing passage number and from different functional groups. Significantly, all the genes present in Region of Diversity 10 (RD10) are required for virulence during blood stream infection showed enhanced expression after passage. However, there was no significant decrease in the LD(50) of serial passage strains compare to single passage strain in a mouse challenge model. Overall, our data suggest that bacteria adapt to extended laboratory passage by substantially altering gene expression. Furthermore, extended passage on blood agar plates reduces the expression of genes associated with initial colonization and adherence but enhances the expression of genes needed for systemic infection.
- Published
- 2009
- Full Text
- View/download PDF
40. Investigation of chemometric instrumental transfer methods for high-resolution NMR.
- Author
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Alam TM, Alam MK, McIntyre SK, Volk DE, Neerathilingam M, and Luxon BA
- Subjects
- Algorithms, Calibration, Computer Simulation, Magnetic Resonance Spectroscopy standards, Models, Statistical, Magnetic Resonance Spectroscopy instrumentation, Magnetic Resonance Spectroscopy methods
- Abstract
The implementation of direct standardization (DS), piecewise direct standardization (PDS), and double-window piecewise direct standardization (DWPDS) instrumental transfer techniques for high-resolution (1)H NMR spectral data was explored. The ability to transfer a multivariate calibration model developed for a "master or target" NMR instrument configuration to seven different ("secondary") NMR instrument configurations was measured. Partial least-squares (PLS) calibration of glucose, glycine, and citrate metabolite relative concentrations in model mixtures following mapping of the secondary instrumental configurations using DS, PDS, or DWPDS instrumental transfer allowed the performance of the different transfer methods to be assessed. Results from these studies suggest that DS and PDS transfer techniques produce similar improvements in the error of prediction compared to each other and provide a significant improvement over standard spectral preprocessing techniques including reference deconvolution and spectral binning. The DS instrumental transfer method produced the largest percent improvement in the predictions of concentrations for these model mixtures but, in general, required that additional transfer calibration standards be used. Limitations of the different instrumental transfer methods with respect to sample subset selection are also discussed.
- Published
- 2009
- Full Text
- View/download PDF
41. Integrin alpha6beta4 controls the expression of genes associated with cell motility, invasion, and metastasis, including S100A4/metastasin.
- Author
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Chen M, Sinha M, Luxon BA, Bresnick AR, and O'Connor KL
- Subjects
- Breast Neoplasms genetics, Breast Neoplasms pathology, Cell Line, Tumor, Cell Movement, DNA Methylation genetics, DNA-Binding Proteins biosynthesis, DNA-Binding Proteins genetics, Female, Follistatin biosynthesis, Follistatin genetics, Gene Expression Profiling, Homeobox Protein Nkx-2.2, Homeodomain Proteins biosynthesis, Homeodomain Proteins genetics, Humans, Integrin alpha6beta4 genetics, LIM Domain Proteins, Microfilament Proteins biosynthesis, Microfilament Proteins genetics, Neoplasm Invasiveness, Neoplasm Metastasis, Neoplasm Proteins genetics, Nuclear Proteins biosynthesis, Nuclear Proteins genetics, Oligonucleotide Array Sequence Analysis, RNA, Small Interfering genetics, S100 Calcium-Binding Protein A4, S100 Proteins genetics, Signal Transduction genetics, Transcription Factors biosynthesis, Transcription Factors genetics, Transcription Factors metabolism, Zebrafish Proteins, Breast Neoplasms metabolism, Gene Expression Regulation, Neoplastic genetics, Integrin alpha6beta4 biosynthesis, Neoplasm Proteins biosynthesis, S100 Proteins biosynthesis
- Abstract
The integrin alpha6beta4 is associated with carcinoma progression by contributing to apoptosis resistance, invasion, and metastasis, due in part to the activation of select transcription factors. To identify genes regulated by the alpha6beta4 integrin, we compared gene expression profiles of MDA-MB-435 cells that stably express integrin alpha6beta4 (MDA/beta4) and vector-only-transfected cells (MDA/mock) using Affymetrix GeneChip analysis. Our results show that integrin alpha6beta4 altered the expression of 538 genes (p < 0.01). Of these genes, 36 are associated with pathways implicated in cell motility and metastasis, including S100A4/metastasin. S100A4 expression correlated well with integrin alpha6beta4 expression in established cell lines. Suppression of S100A4 by small interference RNA resulted in a reduced capacity of alpha6beta4-expressing cells to invade a reconstituted basement membrane in response to lysophosphatidic acid. Using small interference RNA, promoter analysis, and chromatin immunoprecipitation, we demonstrate that S100A4 is regulated by NFAT5, thus identifying the first target of NFAT5 in cancer. In addition, several genes that are known to be regulated by DNA methylation were up-regulated dramatically by integrin alpha6beta4 expression, including S100A4, FST, PDLIM4, CAPG, and Nkx2.2. Notably, inhibition of DNA methyltransferases stimulated expression of these genes in cells lacking the alpha6beta4 integrin, whereas demethylase inhibitors suppressed expression in alpha6beta4 integrin-expressing cells. Alterations in DNA methylation were confirmed by bisulfate sequencing, thus suggesting that integrin alpha6beta4 signaling can lead to the demethylation of select promoters. In summary, our data suggest that integrin alpha6beta4 confers a motile and invasive phenotype to breast carcinoma cells by regulating proinvasive and prometastatic gene expression.
- Published
- 2009
- Full Text
- View/download PDF
42. Analysis of the differential host cell nuclear proteome induced by attenuated and virulent hemorrhagic arenavirus infection.
- Author
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Bowick GC, Spratt HM, Hogg AE, Endsley JJ, Wiktorowicz JE, Kurosky A, Luxon BA, Gorenstein DG, and Herzog NK
- Subjects
- Animals, Cell Line, Cell Nucleus chemistry, Cytoplasm chemistry, Electrophoresis, Gel, Two-Dimensional, Electrophoretic Mobility Shift Assay, Immunoblotting, Macrophages virology, Mice, Protein Binding, Tandem Mass Spectrometry, Arenaviridae immunology, Arenaviridae Infections immunology, Macrophages chemistry, Proteome analysis
- Abstract
Arenaviruses are important emerging pathogens and include a number of hemorrhagic fever viruses classified as NIAID category A priority pathogens and CDC potential biothreat agents. Infection of guinea pigs with the New World arenavirus Pichindé virus (PICV) has been used as a biosafety level 2 model for the Lassa virus. Despite continuing research, little is known about the molecular basis of pathogenesis, and this has hindered the design of novel antiviral therapeutics. Modulation of the host response is a potential strategy for the treatment of infectious diseases. We have previously investigated the global host response to attenuated and lethal arenavirus infections by using high-throughput immunoblotting and kinomics approaches. In this report, we describe the differential nuclear proteomes of a murine cell line induced by mock infection and infection with attenuated and lethal variants of PICV, investigated by using two-dimensional gel electrophoresis. Spot identification using tandem mass spectrometry revealed the involvement of a number of proteins that regulate inflammation via potential modulation of NF-kappaB activity and of several heterogeneous nuclear ribonuclear proteins. Pathway analysis revealed a potential role for transcription factor XBP-1, a transcription factor involved in major histocompatibility complex II (MHC-II) expression; differential DNA-binding activity was revealed by electrophoretic mobility shift assay, and differences in surface MHC-II expression were seen following PICV infection. These data are consistent with the results of several previous studies and highlight potential differences between transcriptional and translational regulation. This study provides a number of differentially expressed targets for further research and suggests that key events in pathogenesis may be established early in infection.
- Published
- 2009
- Full Text
- View/download PDF
43. Transcriptional profiling of mRNA expression in the mouse distal colon.
- Author
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Hoogerwerf WA, Sinha M, Conesa A, Luxon BA, Shahinian VB, Cornélissen G, Halberg F, Bostwick J, Timm J, and Cassone VM
- Subjects
- Animals, Blotting, Western, Cell Proliferation, Colon cytology, Male, Mice, Mice, Inbred C57BL, Microarray Analysis, Proteins metabolism, RNA, Messenger biosynthesis, Reverse Transcriptase Polymerase Chain Reaction, Circadian Rhythm genetics, Colon metabolism, Proteins genetics, RNA, Messenger genetics, Transcription, Genetic
- Abstract
Background & Aims: Intestinal epithelial cells and the myenteric plexus of the mouse gastrointestinal tract contain a circadian clock-based intrinsic time-keeping system. Because disruption of the biological clock has been associated with increased susceptibility to colon cancer and gastrointestinal symptoms, we aimed to identify rhythmically expressed genes in the mouse distal colon., Methods: Microarray analysis was used to identify genes that were rhythmically expressed over a 24-hour light/dark cycle. The transcripts were then classified according to expression pattern, function, and association with physiologic and pathophysiologic processes of the colon., Results: A circadian gene expression pattern was detected in approximately 3.7% of distal colonic genes. A large percentage of these genes were involved in cell signaling, differentiation, and proliferation and cell death. Of all the rhythmically expressed genes in the mouse colon, approximately 7% (64/906) have been associated with colorectal cancer formation (eg, B-cell leukemia/lymphoma-2 [Bcl2]) and 1.8% (18/906) with various colonic functions such as motility and secretion (eg, vasoactive intestinal polypeptide, cystic fibrosis transmembrane conductance regulator)., Conclusions: A subset of genes in the murine colon follows a rhythmic expression pattern. These findings may have significant implications for colonic physiology and pathophysiology.
- Published
- 2008
- Full Text
- View/download PDF
44. CadA negatively regulates Escherichia coli O157:H7 adherence and intestinal colonization.
- Author
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Vazquez-Juarez RC, Kuriakose JA, Rasko DA, Ritchie JM, Kendall MM, Slater TM, Sinha M, Luxon BA, Popov VL, Waldor MK, Sperandio V, and Torres AG
- Subjects
- Adhesins, Bacterial biosynthesis, Adhesins, Bacterial genetics, Animals, Blotting, Western, Carboxy-Lyases genetics, Escherichia coli Infections genetics, Escherichia coli Infections microbiology, Escherichia coli O157 genetics, Escherichia coli O157 metabolism, Escherichia coli Proteins biosynthesis, Escherichia coli Proteins genetics, Gene Expression, Gene Expression Profiling, Oligonucleotide Array Sequence Analysis, Rabbits, Reverse Transcriptase Polymerase Chain Reaction, Bacterial Adhesion physiology, Carboxy-Lyases metabolism, Escherichia coli Infections metabolism, Escherichia coli O157 pathogenicity, Gene Expression Regulation, Bacterial
- Abstract
Adherence of pathogenic Escherichia coli strains to intestinal epithelia is essential for infection. For enterohemorrhagic E. coli (EHEC) serotype O157:H7, we have previously demonstrated that multiple factors govern this pathogen's adherence to HeLa cells (A. G. Torres and J. B. Kaper, Infect. Immun. 71:4985-4995, 2003). One of these factors is CadA, a lysine decarboxylase, and this protein has been proposed to negatively regulate virulence in several enteric pathogens. In the case of EHEC strains, CadA modulates expression of the intimin, an outer membrane adhesin involved in pathogenesis. Here, we inactivated cadA in O157:H7 strain 86-24 to investigate the role of this gene in EHEC adhesion to tissue-cultured monolayers, global gene expression patterns, and colonization of the infant rabbit intestine. The cadA mutant did not possess lysine decarboxylation activity and was hyperadherent to tissue-cultured cells. Adherence of the cadA mutant was nearly twofold greater than that of the wild type, and the adherence phenotype was independent of pH, lysine, or cadaverine in the media. Additionally, complementation of the cadA defect reduced adherence back to wild-type levels, and it was found that the mutation affected the expression of the intimin protein. Disruption of the eae gene (intimin-encoding gene) in the cadA mutant significantly reduced its adherence to tissue-cultured cells. However, adherence of the cadA eae double mutant was greater than that of an 86-24 eae mutant, suggesting that the enhanced adherence of the cadA mutant is not entirely attributable to enhanced expression of intimin in this background. Gene array analysis revealed that the cadA mutation significantly altered EHEC gene expression patterns; expression of 1,332 genes was downregulated and that of 132 genes was upregulated in the mutant compared to the wild-type strain. Interestingly, the gene expression variation shows an EHEC-biased gene alteration including intergenic regions. Two putative adhesins, flagella and F9 fimbria, were upregulated in the cadA mutant, suggestive of their association with adherence in the absence of the Cad regulatory mechanism. In the infant rabbit model, the cadA mutant outcompeted the wild-type strain in the ileum but not in the cecum or mid-colon, raising the possibility that CadA negatively regulates EHEC pathogenicity in a tissue-specific fashion.
- Published
- 2008
- Full Text
- View/download PDF
45. Heme oxygenase-1 suppresses hepatitis C virus replication and increases resistance of hepatocytes to oxidant injury.
- Author
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Zhu Z, Wilson AT, Mathahs MM, Wen F, Brown KE, Luxon BA, and Schmidt WN
- Subjects
- Carcinoma, Hepatocellular, Cell Division, Cell Line, Tumor, DNA Primers, Heme Oxygenase-1 deficiency, Hepacivirus drug effects, Hepatocytes drug effects, Humans, Liver Neoplasms, RNA, Small Interfering genetics, Replicon genetics, Reverse Transcriptase Polymerase Chain Reaction, Virus Replication drug effects, tert-Butylhydroperoxide pharmacology, Heme Oxygenase-1 genetics, Heme Oxygenase-1 metabolism, Hepacivirus physiology, Hepatocytes enzymology, Oxidants toxicity
- Abstract
Unlabelled: Oxidative injury to hepatocytes occurs as a result of hepatitis C virus (HCV) infection and replication. Modulation of host cell antioxidant enzymes such as heme oxygenase-1 (HO-1) may be useful therapeutically to minimize cellular injury, reduce viral replication, and attenuate liver disease. In this report, we evaluated the effects of HO-1 overexpression on HCV replication and hepatocellular injury. Full-length (FL) (Con1) or nonstructural (NS) replicons (I 389 NS3-3') were transfected with complete human HO-1 sequences or empty vector for control. Cell lines overexpressing HO-1 (twofold to sixfold above basal values) or empty vector were isolated, and their HCV RNA synthesis, pro-oxidant levels, and resistance to oxidative injury were assessed. HO-1 overexpression decreased HCV RNA replication in both FL and NS replicons without affecting cellular growth or DNA synthesis. The attenuation of HCV replication was significantly reversed in both replicon systems with HO-1 small interfering RNA (siRNA) knockdown. Both FL and NS replicons that overexpress HO-1 showed reduced prooxidant levels at baseline and increased resistance to oxidant-induced cytotoxicity. HO-1 induction with hemin also markedly decreased HCV replication in both parental FL and NS replicon cell lines. Conversely, knockdown of HO-1 messenger RNA (mRNA) by siRNA in parental FL or NS replicons did not significantly affect HCV replication, suggesting that less than basal levels of HO-1 had minimal effect on HCV replication., Conclusion: Overexpression or induction of HO-1 results in decreased HCV replication as well as protection from oxidative damage. These findings suggest a potential role for HO-1 in antiviral therapy and therapeutic protection against hepatocellular injury in HCV infection.
- Published
- 2008
- Full Text
- View/download PDF
46. Diagnosis and treatment of autoimmune hepatitis.
- Author
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Luxon BA
- Subjects
- Autoantibodies immunology, Biopsy, Needle, Hepatitis, Autoimmune epidemiology, Hepatitis, Autoimmune immunology, Humans, Liver Transplantation, Autoantibodies blood, Hepatitis, Autoimmune pathology, Hepatitis, Autoimmune therapy
- Abstract
Autoimmune hepatitis (AIH) is an idiopathic hepatitis characterized by inflammation of the liver, presence of autoantibodies, and evidence of increased gamma globulins in the serum. It represents an enigmatic interaction between the immune system, autoantigens, and unknown triggering factors. This article provides a brief summary of the diagnosis of AIH, the natural history of AIH, an approach to the treatment and follow-up of AIH, and the role of liver transplantation in the treatment of AIH.
- Published
- 2008
- Full Text
- View/download PDF
47. Identification of human metapneumovirus-induced gene networks in airway epithelial cells by microarray analysis.
- Author
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Bao X, Sinha M, Liu T, Hong C, Luxon BA, Garofalo RP, and Casola A
- Subjects
- Blotting, Western, Gene Expression Profiling, Host-Pathogen Interactions, Humans, Oligonucleotide Array Sequence Analysis, Respiratory Mucosa virology, Reverse Transcriptase Polymerase Chain Reaction, Up-Regulation, Epithelial Cells virology, Gene Regulatory Networks, Metapneumovirus growth & development
- Abstract
Human metapneumovirus (hMPV) is a major cause of lower respiratory tract infections in infants, elderly and immunocompromised patients. Little is known about the response to hMPV infection of airway epithelial cells, which play a pivotal role in initiating and shaping innate and adaptive immune responses. In this study, we analyzed the transcriptional profiles of airway epithelial cells infected with hMPV using high-density oligonucleotide microarrays. Of the 47,400 transcripts and variants represented on the Affimetrix GeneChip Human Genome HG-U133 plus 2 array, 1601 genes were significantly altered following hMPV infection. Altered genes were then assigned to functional categories and mapped to signaling pathways. Many up-regulated genes are involved in the initiation of pro-inflammatory and antiviral immune responses, including chemokines, cytokines, type I interferon and interferon-inducible proteins. Other important functional classes up-regulated by hMPV infection include cellular signaling, gene transcription and apoptosis. Notably, genes associated with antioxidant and membrane transport activity, several metabolic pathways and cell proliferation were down-regulated in response to hMPV infection. Real-time PCR and Western blot assays were used to confirm the expression of genes related to several of these functional groups. The overall result of this study provides novel information on host gene expression upon infection with hMPV and also serves as a foundation for future investigations of genes and pathways involved in the pathogenesis of this important viral infection. Furthermore, it can facilitate a comparative analysis of other paramyxoviral infections to determine the transcriptional changes that are conserved versus the one that are specific to individual pathogens.
- Published
- 2008
- Full Text
- View/download PDF
48. Combinatorial selection of a single stranded DNA thioaptamer targeting TGF-beta1 protein.
- Author
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Kang J, Lee MS, Copland JA 3rd, Luxon BA, and Gorenstein DG
- Subjects
- Base Sequence, DNA Primers, Electrophoretic Mobility Shift Assay, Humans, Luminescence, Molecular Sequence Data, Protein Binding, Thermodynamics, Aptamers, Nucleotide pharmacology, Combinatorial Chemistry Techniques methods, DNA, Single-Stranded genetics, Phosphorothioate Oligonucleotides pharmacology, Transforming Growth Factor beta1 antagonists & inhibitors
- Abstract
A phosphorothioate single-stranded DNA aptamer (thioaptamer) targeting transforming growth factor-beta1 (TGF-beta1) was isolated by in-vitro combinatorial selection. The aptamer selection procedure was designed to modify the backbone of single-stranded DNA aptamers, where 5' of both A and C are phosphorothioates, since this provides enhanced nuclease resistance as well as higher affinity than that of a phosphate counterpart. The thioaptamer selected from a combinatorial library (5x10(14) sequences) binds to TGF-beta1 protein with an affinity of 90 nM. In this report, sequence, predicted secondary structure, and binding affinity of the selected thioaptamer (T18_1_3) are presented.
- Published
- 2008
- Full Text
- View/download PDF
49. Secreted frizzled-related protein 1 loss contributes to tumor phenotype of clear cell renal cell carcinoma.
- Author
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Gumz ML, Zou H, Kreinest PA, Childs AC, Belmonte LS, LeGrand SN, Wu KJ, Luxon BA, Sinha M, Parker AS, Sun LZ, Ahlquist DA, Wood CG, and Copland JA
- Subjects
- Animals, Carcinoma, Renal Cell chemistry, Cell Line, Tumor, Cell Proliferation, DNA Methylation, Female, Glycoproteins analysis, Glycoproteins genetics, Humans, Intracellular Signaling Peptides and Proteins, Kidney Neoplasms chemistry, Mice, Phenotype, Signal Transduction, Wnt Proteins physiology, Carcinoma, Renal Cell prevention & control, Glycoproteins physiology, Kidney Neoplasms prevention & control, Tumor Suppressor Proteins physiology
- Abstract
Purpose: Incidence and mortality rates for renal cell carcinoma (RCC) have been rising for decades. Unfortunately, the molecular events that support RCC carcinogenesis remain poorly understood. In an effort to gain a better understanding of signaling events in clear cell RCC (cRCC), we investigated the antitumor activity of secreted frizzled-related protein 1 (sFRP1), a negative regulator of Wnt signaling., Experimental Design: Genomic profiling of cRCC tumors and patient-matched normal tissues was done and confirmed using quantitative PCR and immunohistochemistry. Methylation-specific PCR was done on patient samples to evaluate the mechanism responsible for sFRP1 loss. sFRP1 expression was restored in cRCC cells and the effects on tumor phenotype were characterized., Results: Genomic profiling, quantitative PCR, and immunohistochemistry indicated that loss of sFRP1 occurred in cRCC and papillary RCC patient tissues. Twelve Wnt-regulated genes were up-regulated in cRCC tissues, including c-myc and cyclin D1, potentiators of cell proliferation and survival. Methylation of the sFRP1 gene was one mechanism identified for attenuation of sFRP1 mRNA. Stable reexpression of sFRP1 in cRCC cells resulted in decreased expression of Wnt target genes, decreased growth in cell culture, inhibition of anchorage-independent growth, and decreased tumor growth in athymic nude mice., Conclusions: To our knowledge, this is the first report to show that stable restoration of sFRP1 expression in cRCC cells attenuates the cRCC tumor phenotype. Our data support a role for sFRP1 as a tumor suppressor in cRCC and that perhaps loss of sFRP1 is an early, aberrant molecular event in renal cell carcinogenesis.
- Published
- 2007
- Full Text
- View/download PDF
50. Functional genomic analysis reveals cross-talk between peroxisome proliferator-activated receptor gamma and calcium signaling in human colorectal cancer cells.
- Author
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Bush CR, Havens JM, Necela BM, Su W, Chen L, Yanagisawa M, Anastasiadis PZ, Guerra R, Luxon BA, and Thompson EA
- Subjects
- Cell Line, Tumor, Cell Movement, Computational Biology methods, Cytoplasm metabolism, DNA-Binding Proteins, Genomics methods, Humans, Lentivirus metabolism, Models, Biological, Phosphorylation, Signal Transduction, Calcium Signaling, Colorectal Neoplasms metabolism, Intracellular Signaling Peptides and Proteins genetics, Intracellular Signaling Peptides and Proteins physiology, Muscle Proteins genetics, Muscle Proteins physiology, PPAR gamma genetics, PPAR gamma metabolism
- Abstract
Activation of PPARgamma in MOSER cells inhibits anchorage-dependent and anchorage-independent growth and invasion through Matrigel-coated transwell membranes. We carried out a longitudinal two-class microarray analysis in which mRNA abundance was measured as a function of time in cells treated with a thiazolidinedione PPARgamma agonist or vehicle. A statistical machine learning algorithm that employs an empirical Bayesian implementation of the multivariate HotellingT2 score was used to identify differentially regulated genes. HotellingT2 scores, MB statistics, and maximum median differences were used as figures of merit to interrogate genomic ontology of these targets. Three major cohorts of genes were regulated: those involved in metabolism, DNA replication, and migration/motility, reflecting the cellular phenotype that attends activation of PPARgamma. The bioinformatic analysis also inferred that PPARgamma regulates calcium signaling. This response was unanticipated, because calcium signaling has not previously been associated with PPARgamma activation. Ingenuity pathway analysis inferred that the nodal point in this cross-talk was Down syndrome critical region 1 (DSCR1). DSCR1 is an endogenous calcineurin inhibitor that blocks dephosphorylation and activation of members of the cytoplasmic component of nuclear factor of activated T cells transcription factors. Lentiviral short hairpin RNA-mediated knockdown of DSCR1 blocks PPARgamma inhibition of proliferation and invasion, indicating that DSCR1 is required for suppression of transformed properties of early stage colorectal cancer cells by PPARgamma. These data reveal a novel, heretofore unappreciated link between PPARgamma and calcium signaling and indicate that DSCR1, which has previously been thought to function by suppression of the angiogenic response in endothelial cells, may also play a direct role in transformation of epithelial cells.
- Published
- 2007
- Full Text
- View/download PDF
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