237 results on '"Prescott SM"'
Search Results
2. What are the effects of dietary fatty acid modification on platelet eicosanoid metabolism, platelet-activating factor, and platelet function? How might these metabolic alterations influence thrombosis?
- Author
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Prescott, SM, primary
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- 1992
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3. Synthesis and release of platelet-activating factor by stimulated human mononuclear phagocytes
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Elstad, MR, primary, Prescott, SM, additional, McIntyre, TM, additional, and Zimmerman, GA, additional
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- 1988
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4. 131I-labeled fibrinogen in the diagnosis of deep vein thrombosis of the lower extremities
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Prescott, SM, primary, Tikoff, G, additional, Coleman, RE, additional, Richards, KL, additional, Armstrong, JD, additional, Hershgold, EL, additional, McDaniel, DC, additional, and Ganchan, RP, additional
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- 1978
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5. Diabetic Retinopathy during pregnancy in Hispanic women with latent Toxoplasma gondii infection.
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Elliott AF, Ng JS, Ojeleye MO, Cuadros J, Prescott SM, Bruder K, Louis-Jacques AL, Kim K, and Groer ME
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- Female, Humans, Pregnancy, Hispanic or Latino, Prospective Studies, Toxoplasma, Diabetes, Gestational, Diabetic Retinopathy epidemiology, Toxoplasmosis complications, Toxoplasmosis epidemiology
- Abstract
Background: Retinal photography was performed in pregnancy and postpartum in pregnant Hispanic women with latent Toxoplasma gondii (TG) infection in order to screen for characteristic retinal lesions or the particular scars found in people with active T. gondii infection. A comparison group of TG negative women was included in the study but they did not have retinal photography., Objective: The goal of the parent study was to assess for adverse pregnancy events and evidence for parasite reactivation in TG positive (TG + ) women, through examination of the eyes for characteristic lesions. Retinal photography, usually at prenatal visits 2 (17 +/- 3.35 weeks) and 3 (26.3+/-1.75) weeks, was done on TG + women. Fifty-six of these women also (43 %) had retinal photography at the postpartum visit. Health and demographic data were obtained at the first prenatal visit for all women., Study Design: From the 690 recruited at the first prenatal visit, 128 TG- women and 158 TG + women were enrolled in a prospective study through pregnancy and the postpartum. All TG- women (n = 532) provided data at the first prenatal visit and throughout their pregnancy and birth through the EHR. This allowed comparison of health and outcome data for the TG + compared to a larger number of TG- Hispanic pregnant women., Results: While there was no evidence of ocular toxoplasmosis during pregnancy, there was a surprisingly large number (42 %) of TG + women with diabetic retinopathy (DR). We also observed that TG + women had a 20 % incidence of gestational diabetes mellitus (GDM) compared to 11.3 % in the TG- women (p = 0.01). At postpartum (mean 5.6 weeks), 23 of 30 women with pregnancy DR showed no DR in the postpartum., Conclusions: No characteristic T. gondii lesions were discovered. Retinal photography serendipitously revealed DR in these T. gondii positive women. It was also found that latent TG infection was associated with increased incidence of GDM. Hispanic pregnant women's increased risk for latent TG infection, GDM and DR are underappreciated. Retinal photography may need to be considered an innovative approach to screening., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
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- 2024
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6. Neonatal pain assessment: Do we have the right tools?
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Llerena A, Tran K, Choudhary D, Hausmann J, Goldgof D, Sun Y, and Prescott SM
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Background: The assessment and management of neonatal pain is crucial for the development and wellbeing of vulnerable infants. Specifically, neonatal pain is associated with adverse health outcomes but is often under-identified and therefore under-treated. Neonatal stress may be misinterpreted as pain and may therefore be treated inappropriately. The assessment of neonatal pain is complicated by the non-verbal status of patients, age-dependent variation in pain responses, limited education on identifying pain in premature infants, and the clinical utility of existing tools., Objective: We review research surrounding neonatal pain assessment scales currently in use to assess neonatal pain in the neonatal intensive care unit., Methods: We performed a systematic review of original research using PRISMA guidelines for literature published between 2016 and 2021 using the key words "neonatal pain assessment" in the databases Web of Science, PubMed, and CINAHL. Fifteen articles remained after review, duplicate, irrelevant, or low-quality articles were eliminated., Results: We found research evaluating 13 neonatal pain scales. Important measurement categories include behavioral parameters, physiological parameters, continuous pain, acute pain, chronic pain, and the ability to distinguish between pain and stress. Provider education, inter-rater reliability and ease of use are important factors that contribute to an assessment tool's success. Each scale studied had strengths and limitations that aided or hindered its use for measuring neonatal pain in the neonatal intensive care unit, but no scale excelled in all areas identified as important for reliably identifying and measuring pain in this vulnerable population., Conclusion: A more comprehensive neonatal pain assessment tool and more provider education on differences in pain signals in premature neonates may be needed to increase the clinical utility of pain scales that address the different aspects of neonatal pain., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Llerena, Tran, Choudhary, Hausmann, Goldgof, Sun and Prescott.)
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- 2023
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7. Relationships of the very low birth weight infant microbiome with neurodevelopment at 2 and 4 years of age.
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Sarkar A, Prescott SM, Dutra S, Yoo JY, Gordon J, Shaffer E, McSkimming D, and Groer ME
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- Infant, Newborn, Infant, Adult, Humans, Child, Preschool, Intensive Care Units, Neonatal, Gestational Age, Birth Weight, Anti-Bacterial Agents, Infant, Very Low Birth Weight, Microbiota
- Abstract
Very low birth weight (VLBW) infants (<1500 g) are at risk for poor neurodevelopmental outcomes depending on gestational age (GA), birth weight (BW), and morbidity in early life. The contribution of the gut microbiome is not well understood. Stool samples were collected weekly in the neonatal intensive care unit (NICU) from 24 VLBW infants for 6 weeks after admission and then again at 2 and 4 years of age. The Battelle Development Inventory-2 Screening Test (BDI-2 ST) was administered at 2- and 4-year time points. VLBW infants had dysbiotic microbiota in the NICU that progressed for most to an adult-type microbiota by 4 years of age. The BDI-2 ST results at age of 2 years triggered referral for further testing in 14 toddlers (70%), and by 4 years of age only seven of these 14 continued to require referral. Both NICU infant stool diversity and particular microbial amplicon sequence variants were associated with BDI-2 ST subscales, particularly for cognition, adaptive, and communication subscales, when controlled for GA, BW, and antibiotic exposure. Network analysis of the NICU infant stool microbial ecology showed differences in children needing neurodevelopmental referral. The results of this preliminary study indicate that the neonatal gut microbiome plays a role in early cognitive and behavioral neurodevelopment., (© 2022 Wiley Periodicals LLC.)
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- 2022
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8. Intestinal microbiota signatures of clinical response and immune-related adverse events in melanoma patients treated with anti-PD-1.
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McCulloch JA, Davar D, Rodrigues RR, Badger JH, Fang JR, Cole AM, Balaji AK, Vetizou M, Prescott SM, Fernandes MR, Costa RGF, Yuan W, Salcedo R, Bahadiroglu E, Roy S, DeBlasio RN, Morrison RM, Chauvin JM, Ding Q, Zidi B, Lowin A, Chakka S, Gao W, Pagliano O, Ernst SJ, Rose A, Newman NK, Morgun A, Zarour HM, Trinchieri G, and Dzutsev AK
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- Bacteria genetics, Humans, Immunotherapy adverse effects, Gastrointestinal Microbiome genetics, Melanoma drug therapy, Microbiota
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Ample evidence indicates that the gut microbiome is a tumor-extrinsic factor associated with antitumor response to anti-programmed cell death protein-1 (PD-1) therapy, but inconsistencies exist between published microbial signatures associated with clinical outcomes. To resolve this, we evaluated a new melanoma cohort, along with four published datasets. Time-to-event analysis showed that baseline microbiota composition was optimally associated with clinical outcome at approximately 1 year after initiation of treatment. Meta-analysis and other bioinformatic analyses of the combined data show that bacteria associated with favorable response are confined within the Actinobacteria phylum and the Lachnospiraceae/Ruminococcaceae families of Firmicutes. Conversely, Gram-negative bacteria were associated with an inflammatory host intestinal gene signature, increased blood neutrophil-to-lymphocyte ratio, and unfavorable outcome. Two microbial signatures, enriched for Lachnospiraceae spp. and Streptococcaceae spp., were associated with favorable and unfavorable clinical response, respectively, and with distinct immune-related adverse effects. Despite between-cohort heterogeneity, optimized all-minus-one supervised learning algorithms trained on batch-corrected microbiome data consistently predicted outcomes to programmed cell death protein-1 therapy in all cohorts. Gut microbial communities (microbiotypes) with nonuniform geographical distribution were associated with favorable and unfavorable outcomes, contributing to discrepancies between cohorts. Our findings shed new light on the complex interaction between the gut microbiome and response to cancer immunotherapy, providing a roadmap for future studies., (© 2022. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.)
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- 2022
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9. Responses to 10 common criticisms of anti-racism action in STEMM.
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Gosztyla ML, Kwong L, Murray NA, Williams CE, Behnke N, Curry P, Corbett KD, DSouza KN, Gala de Pablo J, Gicobi J, Javidnia M, Lotay N, Prescott SM, Quinn JP, Rivera ZMG, Smith MA, Tang KTY, Venkat A, and Yamoah MA
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- Humans, Engineering organization & administration, Natural Science Disciplines organization & administration, Racism, Social Justice
- Abstract
Competing Interests: The authors have declared that no competing interests exist.
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- 2021
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10. Bacterial clearance is improved in septic mice by platelet-activating factor-acetylhydrolase (PAF-AH) administration.
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Teixeira-da-Cunha MG, Gomes RN, Roehrs N, Bozza FA, Prescott SM, Stafforini D, Zimmerman GA, Bozza PT, and Castro-Faria-Neto HC
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- Animals, Chemokine CCL2 biosynthesis, Disease Models, Animal, Humans, Male, Mice, Nitric Oxide biosynthesis, Peritoneal Cavity microbiology, Recombinant Proteins administration & dosage, Salmonella Infections drug therapy, Salmonella Infections microbiology, Salmonella typhimurium, Sepsis metabolism, 1-Alkyl-2-acetylglycerophosphocholine Esterase administration & dosage, Sepsis drug therapy, Sepsis microbiology
- Abstract
Current evidence indicates that dysregulation of the host inflammatory response to infectious agents is central to the mortality of patients with sepsis. Strategies to block inflammatory mediators such as PAF have been investigated as adjuvant therapies for sepsis. PAF-AH, the enzyme responsible for PAF degradation, showed positive results in pre-clinical studies and phase II clinical trials, but the results of a phase III study were disappointing. In this study, we investigated the potential protective mechanism of PAF-AH in sepsis using the murine model of cecal ligation and puncture (CLP). Treatment with rPAF-AH increased peritoneal fluid levels of the anti-inflammatory mediators MCP-1/CCL2 after CLP. The numbers of bacteria (CFU) in the peritoneal cavity were decreased in the rPAF-AH-treated group, indicating more efficient bacterial clearance after rPAF-AH treatment. Interestingly, we observed increased levels of nitric oxide (NO) after PAF-AH administration, and rPAF-AH treatment did not decrease CFU numbers either in iNOS-deficient mice or in CCR2-deficient mice. We concluded that administration of exogenous rPAF-AH reduced inflammatory injury, altered cytokine levels and favored bacterial clearance with a clear impact on mortality through modulation of MCP-1/CCL2 and NO levels in a clinically relevant sepsis model.
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- 2013
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11. DGKι regulates presynaptic release during mGluR-dependent LTD.
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Yang J, Seo J, Nair R, Han S, Jang S, Kim K, Han K, Paik SK, Choi J, Lee S, Bae YC, Topham MK, Prescott SM, Rhee JS, Choi SY, and Kim E
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- Animals, Brain ultrastructure, Cell Line, Cells, Cultured, Diacylglycerol Kinase genetics, Dizocilpine Maleate metabolism, Gene Deletion, Gene Expression, Humans, Mice, Neurons metabolism, Neurons ultrastructure, Neurotransmitter Agents metabolism, Protein Kinase C metabolism, Rats, Rats, Sprague-Dawley, Receptors, N-Methyl-D-Aspartate metabolism, Synaptic Transmission, Brain metabolism, Diacylglycerol Kinase analysis, Diacylglycerol Kinase metabolism, Nerve Tissue Proteins metabolism, Receptors, Metabotropic Glutamate metabolism, Synapses metabolism
- Abstract
Diacylglycerol (DAG) is an important lipid second messenger. DAG signalling is terminated by conversion of DAG to phosphatidic acid (PA) by diacylglycerol kinases (DGKs). The neuronal synapse is a major site of DAG production and action; however, how DGKs are targeted to subcellular sites of DAG generation is largely unknown. We report here that postsynaptic density (PSD)-95 family proteins interact with and promote synaptic localization of DGKι. In addition, we establish that DGKι acts presynaptically, a function that contrasts with the known postsynaptic function of DGKζ, a close relative of DGKι. Deficiency of DGKι in mice does not affect dendritic spines, but leads to a small increase in presynaptic release probability. In addition, DGKι-/- synapses show a reduction in metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD) at neonatal (∼2 weeks) stages that involve suppression of a decrease in presynaptic release probability. Inhibition of protein kinase C normalizes presynaptic release probability and mGluR-LTD at DGKι-/- synapses. These results suggest that DGKι requires PSD-95 family proteins for synaptic localization and regulates presynaptic DAG signalling and neurotransmitter release during mGluR-LTD.
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- 2011
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12. Synaptic removal of diacylglycerol by DGKzeta and PSD-95 regulates dendritic spine maintenance.
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Kim K, Yang J, Zhong XP, Kim MH, Kim YS, Lee HW, Han S, Choi J, Han K, Seo J, Prescott SM, Topham MK, Bae YC, Koretzky G, Choi SY, and Kim E
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- Animals, Cells, Cultured, Dendritic Spines ultrastructure, Diacylglycerol Kinase genetics, Diglycerides metabolism, Disks Large Homolog 4 Protein, Guanylate Kinases, Humans, Intracellular Signaling Peptides and Proteins genetics, Isoenzymes genetics, Male, Membrane Proteins genetics, Mice, Mice, Knockout, Neurons cytology, Neurons metabolism, Patch-Clamp Techniques, Protein Kinase C antagonists & inhibitors, Protein Kinase C metabolism, Rats, Rats, Sprague-Dawley, Synapses ultrastructure, Dendritic Spines metabolism, Diacylglycerol Kinase metabolism, Intracellular Signaling Peptides and Proteins metabolism, Isoenzymes metabolism, Membrane Proteins metabolism, Synapses metabolism, Synaptic Transmission physiology
- Abstract
Diacylglycerol (DAG) is an important lipid signalling molecule that exerts an effect on various effector proteins including protein kinase C. A main mechanism for DAG removal is to convert it to phosphatidic acid (PA) by DAG kinases (DGKs). However, it is not well understood how DGKs are targeted to specific subcellular sites and tightly regulates DAG levels. The neuronal synapse is a prominent site of DAG production. Here, we show that DGKzeta is targeted to excitatory synapses through its direct interaction with the postsynaptic PDZ scaffold PSD-95. Overexpression of DGKzeta in cultured neurons increases the number of dendritic spines, which receive the majority of excitatory synaptic inputs, in a manner requiring its catalytic activity and PSD-95 binding. Conversely, DGKzeta knockdown reduces spine density. Mice deficient in DGKzeta expression show reduced spine density and excitatory synaptic transmission. Time-lapse imaging indicates that DGKzeta is required for spine maintenance but not formation. We propose that PSD-95 targets DGKzeta to synaptic DAG-producing receptors to tightly couple synaptic DAG production to its conversion to PA for the maintenance of spine density.
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- 2009
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13. Can licorice lick colon cancer?
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Stewart PM and Prescott SM
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- 11-beta-Hydroxysteroid Dehydrogenase Type 2 antagonists & inhibitors, Animals, Anti-Inflammatory Agents, Non-Steroidal adverse effects, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Colonic Neoplasms enzymology, Cyclooxygenase 2 Inhibitors adverse effects, Cyclooxygenase 2 Inhibitors therapeutic use, Enzyme Inhibitors therapeutic use, Humans, Hydrocortisone metabolism, Mice, Phytotherapy, Plant Extracts therapeutic use, Colonic Neoplasms drug therapy, Glycyrrhiza
- Abstract
COX-2 promotes colon cancer. While both nonselective NSAIDs and selective COX-2 inhibitors reduce disease burden, their adverse gastrointestinal and cardiovascular side effects limit their therapeutic use. In this issue of the JCI, Zhang et al. used gene silencing and a derivative of licorice root to show that inhibition of the enzyme 11beta-hydroxysteroid dehydrogenase type II(11betaHSD2) reduces tumor COX-2 activity, tumor growth, and metastasis by increasing the tonic glucocorticoid-mediated suppression of the COX-2 signaling pathway without the adverse effects associated with NSAIDs and selective COX-2 inhibitors (see the related article beginning on page 876). Their findings suggest that 11betaHSD2 inhibition may be a potential therapeutic option in colon cancer, warranting further investigation.
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- 2009
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14. The emerging roles of PAF acetylhydrolase.
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McIntyre TM, Prescott SM, and Stafforini DM
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- Animals, Apoptosis, Humans, Inflammation, Platelet Activating Factor metabolism, Substrate Specificity, 1-Alkyl-2-acetylglycerophosphocholine Esterase metabolism
- Abstract
Platelet-activating factor (PAF), a phospholipid autacoid with potent effects throughout the innate immune system, is selectively degraded by two small families of PAF acetylhydrolases (PAF-AHs). These Ca2+-independent phospholipases A2 display remarkable specificity for the length of the sn-2 residue, but this selectivity is lost as the residue gains oxygen functions. Two of the PAF-AHs therefore are specific oxidized phospholipid phospholipases that reduce inflammation, but also remove oxidatively truncated phospholipids that induce apoptosis. The roles of these enzymes are manifold, and their separate and combined functions are now being addressed in model systems and clinical studies.
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- 2009
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15. Transgenic expression of cyclooxygenase-2 in mouse intestine epithelium is insufficient to initiate tumorigenesis but promotes tumor progression.
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Al-Salihi MA, Terrece Pearman A, Doan T, Reichert EC, Rosenberg DW, Prescott SM, Stafforini DM, and Topham MK
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- Animals, Cyclooxygenase 2 biosynthesis, Disease Progression, Female, Humans, Male, Mice, Mice, Transgenic, Signal Transduction, Cyclooxygenase 2 genetics, Epithelium metabolism, ErbB Receptors metabolism, Gene Expression Regulation, Neoplastic, Intestinal Mucosa metabolism, Proto-Oncogene Proteins c-akt metabolism, Transgenes
- Abstract
We generated mice expressing a COX-2 transgene in colon epithelium and found that they did not develop spontaneous colon tumors. But when treated with azoxymethane, a colon carcinogen, COX-2 mice had a higher tumor load compared to wild-type mice. There was no change in the number of pre-neoplastic lesions, indicating that COX-2 does not affect tumor initiation. Tumors in the COX-2 transgenic mice had higher levels of phosphorylated epidermal growth factor receptor and Akt compared to wild-type mice. Collectively, our data indicate that COX-2 promotes colon tumor progression, but not initiation, and it does so, in part, by activating EGFR and Akt signaling pathways.
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- 2009
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16. From linkage maps to quantitative trait loci: the history and science of the Utah genetic reference project.
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Prescott SM, Lalouel JM, and Leppert M
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- Aging genetics, Chromosomes, Human genetics, Cooperative Behavior, Female, Gene Expression, History, 20th Century, History, 21st Century, Humans, Male, Pedigree, Polymorphism, Genetic, Receptors, G-Protein-Coupled genetics, Telomere genetics, Utah, Chromosome Mapping history, Human Genome Project history, Quantitative Trait Loci
- Abstract
One of the early decisions in what became the Human Genome Project was to recruit families that would serve as a reference set, thereby focusing efforts to create human genetic maps on the same sets of DNA samples. The families recruited from Utah provided the most widely used samples in the Centre d'Etudes du Polymorphisme Humain (CEPH) set, were instrumental in generating human linkage maps, and often serve as the benchmark for establishing allele frequency when a new variant is identified. In addition, the immortalized cell lines created from the peripheral blood cells of these subjects are a broadly used resource and have yielded insights in many areas, from the genetics of gene expression to the regulation of telomeres. More recently, these families were recontacted and underwent extensive, protocol-based evaluation to create a phenotypic database, which will aid in the study of the genetic basis of quantitative traits. As with the earlier efforts, this project involved collaborations among many investigators and has yielded insights into multiple traits.
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- 2008
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17. Integrin alphaDbeta2 is dynamically expressed by inflamed macrophages and alters the natural history of lethal systemic infections.
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Miyazaki Y, Bunting M, Stafforini DM, Harris ES, McIntyre TM, Prescott SM, Frutuoso VS, Amendoeira FC, de Oliveira Nascimento D, Vieira-de-Abreu A, Weyrich AS, Castro-Faria-Neto HC, and Zimmerman GA
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- Animals, CD11 Antigens genetics, Cytokines metabolism, Inflammation immunology, Integrin alpha Chains genetics, Liver immunology, Macrophage Activation, Malaria mortality, Mice, Mice, Knockout, Sepsis mortality, Spleen immunology, CD11 Antigens metabolism, Integrin alpha Chains metabolism, Macrophages immunology, Malaria immunology, Plasmodium berghei, Salmonella, Sepsis immunology
- Abstract
The leukocyte integrins have critical roles in host defense and inflammatory tissue injury. We found that integrin alphaDbeta2, a novel but largely uncharacterized member of this family, is restricted to subsets of macrophages and a small population of circulating leukocytes in wild-type mice in the absence of inflammatory challenge and is expressed in regulated fashion during cytokine-induced macrophage differentiation in vitro. alphaDbeta2 is highly displayed on splenic red pulp macrophages and mediates their adhesion to local targets, identifying key functional activity. In response to challenge with Plasmodium berghei, a malarial pathogen that models systemic infection and inflammatory injury, new populations of alphaD+ macrophages evolved in the spleen and liver. Unexpectedly, targeted deletion of alphaD conferred a survival advantage in P. berghei infection over a 30-day observation period. Mechanistic studies demonstrated that the increased survival of alphaD-/- animals at these time points is not attributed to differences in magnitude of anemia or parasitemia or to alterations in splenic microanatomy, each of which is a key variable in the natural history of P. berghei infection, and indicated that an altered pattern of inflammatory cytokines may contribute to the difference in mortality. In contrast to the outcome in malarial challenge, death of alphaD-/- animals was accelerated in a model of Salmonella sepsis, demonstrating differential rather than stereotyped roles for alphaDbeta2 in systemic infection. These studies identify previously unrecognized and unique activities of alphaDbeta2, and macrophages that express it, in host defense and injury.
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- 2008
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18. Retinoic acid inhibits beta-catenin through suppression of Cox-2: a role for truncated adenomatous polyposis coli.
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Eisinger AL, Nadauld LD, Shelton DN, Prescott SM, Stafforini DM, and Jones DA
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- Animals, Dinoprostone metabolism, Down-Regulation, Immunoblotting, In Situ Hybridization, RNA metabolism, Signal Transduction, Zebrafish, beta Catenin antagonists & inhibitors, Adenomatous Polyposis Coli metabolism, Cyclooxygenase 2 metabolism, Gene Expression Regulation, Mutation, Tretinoin pharmacology, beta Catenin metabolism
- Abstract
Mutations in adenomatous polyposis coli (APC) underlie the earliest stages of colorectal carcinogenesis. Consequences of APC mutation include stabilization of beta-catenin, dysregulation of cyclooxygenase-2 (COX-2) expression, and loss of retinoic acid production, events with poorly defined interactions. Here we showed that treatment of zebrafish expressing a truncated form of Apc with either retinoic acid or a selective COX-2 inhibitor decreased beta-catenin protein levels and downstream signaling events. Interestingly, the destruction of beta-catenin in apc mutant embryos following Cox-2 inhibition required the presence of truncated Apc. These findings support roles for retinoic acid and Cox-2 in regulating the stability of beta-catenin following Apc loss. Furthermore, truncated Apc appears to retain the ability to target beta-catenin for destruction, but only in the absence of Cox-2 activity. This novel function of truncated Apc may provide a molecular basis for the efficacy of COX-2 inhibitors in the treatment of colon cancer.
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- 2007
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19. IFN-epsilon mediates TNF-alpha-induced STAT1 phosphorylation and induction of retinoic acid-inducible gene-I in human cervical cancer cells.
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Matsumiya T, Prescott SM, and Stafforini DM
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- DEAD Box Protein 58, Female, HeLa Cells, Humans, Interferons genetics, Phosphorylation drug effects, Promoter Regions, Genetic genetics, RNA, Messenger genetics, Receptors, Immunologic, Receptors, Interferon classification, Receptors, Interferon metabolism, Signal Transduction, Up-Regulation drug effects, Uterine Cervical Neoplasms genetics, DEAD-box RNA Helicases metabolism, Interferons metabolism, STAT1 Transcription Factor metabolism, Tumor Necrosis Factor-alpha pharmacology, Uterine Cervical Neoplasms metabolism
- Abstract
Retinoic acid inducible gene-I (RIG-I) plays important roles during innate immune responses to viral infections and as a transducer of cytokine signaling. The mechanisms of RIG-I up-regulation after cytokine stimulation are incompletely characterized. It was previously reported that IFN-gamma induces the expression of RIG-I in endothelial cells. In this study, we characterized the mechanism of type I IFN-mediated up-regulation of RIG-I in HeLa cells and found that, in addition to type I IFN, TNF-alpha, a cytokine that regulates innate immune responses, induced expression of RIG-I. To investigate whether TNF-alpha- and type I IFN-mediated up-regulations of RIG-I were causally related, we studied the kinetics of these responses. Our results were consistent with a model in which TNF-alpha functioned upstream of type I IFNs. The ability of TNF-alpha to up-regulate RIG-I required protein synthesis, expression of functional type I IFNRs, and STAT1 signaling. We also found that IFN-epsilon was the only IFN isoform expressed constitutively in HeLa cells and that its expression was up-regulated in response to stimulation with TNF-alpha. The mechanism of up-regulation involved stabilization of IFN-epsilon mRNA in the absence of transcriptional activation. Silencing the expression of IFN-epsilon attenuated STAT1 expression and phosphorylation and inhibited RIG-I expression, providing additional support for the participation of IFN-epsilon upstream of STAT1. Our findings support a sequential mechanism whereby TNF-alpha leads to stabilization of IFN-epsilon mRNA, increased IFN-epsilon synthesis, engagement of type I IFNRs, increased STAT1 expression and phosphorylation, and up-regulation of RIG-I expression. These findings have implications for our understanding of the immune responses that follow cytokine stimulation.
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- 2007
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20. Cyclooxygenase-2 transactivates the epidermal growth factor receptor through specific E-prostanoid receptors and tumor necrosis factor-alpha converting enzyme.
- Author
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Al-Salihi MA, Ulmer SC, Doan T, Nelson CD, Crotty T, Prescott SM, Stafforini DM, and Topham MK
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- ADAM17 Protein, Animals, COS Cells, Cell Culture Techniques, Cell Proliferation drug effects, Chlorocebus aethiops, Cyclooxygenase 2 genetics, Dinoprostone pharmacology, Enzyme Inhibitors pharmacology, Epithelial Cells cytology, Epithelial Cells drug effects, Epithelial Cells enzymology, Gene Expression Regulation, Enzymologic drug effects, Humans, Intercellular Signaling Peptides and Proteins metabolism, Membrane Proteins antagonists & inhibitors, Membrane Proteins genetics, Metalloproteases metabolism, Mice, RNA, Messenger genetics, RNA, Messenger metabolism, Transcriptional Activation drug effects, Transforming Growth Factor alpha metabolism, ADAM Proteins metabolism, Cyclooxygenase 2 metabolism, ErbB Receptors genetics, Membrane Proteins metabolism, Receptors, Prostaglandin E metabolism, Transcriptional Activation genetics
- Abstract
Cyclooxygenase-2 is often highly expressed in epithelial malignancies and likely has an active role in tumor development. But how it promotes tumorigenesis is not clearly defined. Recent evidence suggests that this may involve transactivation of the epidermal growth factor receptor through E-prostanoid receptors, but reports differ about the mechanism by which this occurs. We found that E-prostanoid receptors 2-4, but not 1, transactivated the epidermal growth factor receptor. This required metalloproteinase activity, leading to release of growth factors from the cell surface. Both transforming growth factor-alpha and amphiregulin were released in response to over-expression of cyclooxygenase-2, but betacellulin and heparin-binding EGF-like growth factor were not. The metalloproteinase tumor necrosis factor-alpha converting enzyme was required for proteolytic release of transforming growth factor-alpha. We also found that addition of epidermal growth factor receptor ligands to HEK293 cells induced cyclooxygenase-2 expression, suggesting that by activating epidermal growth factor receptor signaling, cyclooxygenase-2 potentially creates a self-perpetuating cycle of cell growth. Consistent with this, inhibition of cyclooxygenase-2 reduced growth of epidermal growth factor receptor over-expressing MCF-10A breast epithelial cells in three-dimensional culture.
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- 2007
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21. Lung production of platelet-activating factor acetylhydrolase in oleic acid-induced acute lung injury.
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Salluh JI, Pino AV, Silva AR, Gomes RN, Souza HS, e Silva JR, Jandre FC, Giannella-Neto A, Zimmerman GA, Stafforini DM, Prescott SM, Castro-Faria-Neto HC, Bozza PT, and Bozza FA
- Subjects
- 1-Alkyl-2-acetylglycerophosphocholine Esterase blood, Animals, Bronchoalveolar Lavage Fluid chemistry, Female, Immunohistochemistry, Kinetics, Lung metabolism, Oleic Acid, Respiratory Distress Syndrome chemically induced, Swine, Time Factors, 1-Alkyl-2-acetylglycerophosphocholine Esterase biosynthesis, Lung enzymology, Respiratory Distress Syndrome enzymology
- Abstract
Platelet-activating factor (PAF) is a proinflammatory mediator that plays a central role in acute lung injury (ALI). PAF- acetylhydrolases (PAF-AHs) terminate PAF's signals and regulate inflammation. In this study, we describe the kinetics of plasma and bronchoalveolar lavage (BAL) PAF-AH in the early phase of ALI. Six pigs with oleic acid induced ALI and two healthy controls were studied. Plasma and BAL samples were collected every 2h and immunohistochemical analysis of PAF-AH was performed in lung tissues. PAF-AH activity in BAL was increased at the end of the experiment (BAL PAF-AH Time 0=0.001+/-0.001 nmol/ml/min/g vs Time 6=0.031+/-0.018 nmol/ml/min/g, p=0.04) while plasma activity was not altered. We observed increased PAF-AH staining of macrophages and epithelial cells in the lungs of animals with ALI but not in healthy controls. Our data suggest that increases in PAF-AH levels are, in part, a result of alveolar production. PAF-AH may represent a modulatory strategy to counteract the excessive pro-inflammatory effects of PAF and PAF-like lipids in lung inflammation.
- Published
- 2007
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22. Molecular basis for susceptibility of plasma platelet-activating factor acetylhydrolase to oxidative inactivation.
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MacRitchie AN, Gardner AA, Prescott SM, and Stafforini DM
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- Animals, COS Cells, Chlorocebus aethiops, Humans, Lipoproteins chemistry, Mice, Oxidants metabolism, Oxidative Stress, Oxygen metabolism, Peroxynitrous Acid pharmacology, Phospholipases A metabolism, Phospholipases A2, Phospholipids metabolism, Reactive Oxygen Species, Tyrosine chemistry, 1-Alkyl-2-acetylglycerophosphocholine Esterase blood, 1-Alkyl-2-acetylglycerophosphocholine Esterase chemistry
- Abstract
Platelet-activating factor acetylhydrolase (PAF-AH) is a phospholipase A2 that inactivates potent lipid messengers, such as PAF and modified phospholipids generated in settings of oxidant stress. The catalytic activity of PAF-AH is sensitive to oxidants, a feature that may have pathological consequences. We report that peroxynitrite, an oxidant species generated after cellular activation, mediates oxidative inactivation of PAF-AH. We found that peroxynitrite inactivated and derivatized the recombinant protein and obtained evidence supporting a role for a methionine and two tyrosine residues in this process. We employed interspecies comparisons and site-directed mutagenesis and identified a role for M-117, and a smaller contribution of Y-307 and Y-335 as targets of oxidant attack using free and lipoprotein-associated recombinant proteins. M-117 is adjacent to W-115 and L-116, which are essential for association of PAF-AH with LDL. Oxidation of LDL-associated PAF-AH partially dissociated the enzyme from the particles. Similarly, oxidation of the purified enzyme in the absence of lipoproteins prevented subsequent association with LDL. These results provide new insights into the molecular mechanisms that mediate inactivation of PAF-AH in settings of oxidant stress and the consequences of oxidation on the ability of this enzyme to associate with LDL.
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- 2007
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23. Targeting of diacylglycerol degradation to M1 muscarinic receptors by beta-arrestins.
- Author
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Nelson CD, Perry SJ, Regier DS, Prescott SM, Topham MK, and Lefkowitz RJ
- Subjects
- Animals, COS Cells, Carbachol pharmacology, Cell Line, Chlorocebus aethiops, Diacylglycerol Kinase genetics, Humans, Mutation, Phosphatidic Acids metabolism, Protein Binding, RNA, Small Interfering, Recombinant Fusion Proteins metabolism, Second Messenger Systems, Transfection, beta-Arrestins, Arrestins metabolism, Diacylglycerol Kinase metabolism, Diglycerides metabolism, Receptor, Muscarinic M1 metabolism, Signal Transduction
- Abstract
Seven-transmembrane receptor (7TMR) signaling is transduced by second messengers such as diacylglycerol (DAG) generated in response to the heterotrimeric guanine nucleotide-binding protein Gq and is terminated by receptor desensitization and degradation of the second messengers. We show that beta-arrestins coordinate both processes for the Gq-coupled M1 muscarinic receptor. beta-Arrestins physically interact with diacylglycerol kinases (DGKs), enzymes that degrade DAG. Moreover, beta-arrestins are essential for conversion of DAG to phosphatidic acid after agonist stimulation, and this activity requires recruitment of the beta-arrestin-DGK complex to activated 7TMRs. The dual function of beta-arrestins, limiting production of diacylglycerol (by receptor desensitization) while enhancing its rate of degradation, is analogous to their ability to recruit adenosine 3',5'-monophosphate phosphodiesterases to Gs-coupled beta2-adrenergic receptors. Thus, beta-arrestins can serve similar regulatory functions for disparate classes of 7TMRs through structurally dissimilar enzymes that degrade chemically distinct second messengers.
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- 2007
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- View/download PDF
24. A large-scale genetic association study confirms IL12B and leads to the identification of IL23R as psoriasis-risk genes.
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Cargill M, Schrodi SJ, Chang M, Garcia VE, Brandon R, Callis KP, Matsunami N, Ardlie KG, Civello D, Catanese JJ, Leong DU, Panko JM, McAllister LB, Hansen CB, Papenfuss J, Prescott SM, White TJ, Leppert MF, Krueger GG, and Begovich AB
- Subjects
- Adolescent, Adult, Bayes Theorem, Case-Control Studies, Child, Female, Genetics, Population, Haplotypes, Humans, Male, Middle Aged, Monte Carlo Method, Polymorphism, Single Nucleotide, Receptors, Interleukin-12 genetics, Genetic Predisposition to Disease, Interleukin-12 Subunit p40 genetics, Psoriasis genetics, Receptors, Interleukin genetics
- Abstract
We performed a multitiered, case-control association study of psoriasis in three independent sample sets of white North American individuals (1,446 cases and 1,432 controls) with 25,215 genecentric single-nucleotide polymorphisms (SNPs) and found a highly significant association with an IL12B 3'-untranslated-region SNP (rs3212227), confirming the results of a small Japanese study. This SNP was significant in all three sample sets (odds ratio [OR](common) 0.64, combined P [Pcomb]=7.85x10(-10)). A Monte Carlo simulation to address multiple testing suggests that this association is not a type I error. The coding regions of IL12B were resequenced in 96 individuals with psoriasis, and 30 additional IL12B-region SNPs were genotyped. Haplotypes were estimated, and genotype-conditioned analyses identified a second risk allele (rs6887695) located approximately 60 kb upstream of the IL12B coding region that exhibited association with psoriasis after adjustment for rs3212227. Together, these two SNPs mark a common IL12B risk haplotype (OR(common) 1.40, Pcomb=8.11x10(-9)) and a less frequent protective haplotype (OR(common) 0.58, Pcomb=5.65x10(-12)), which were statistically significant in all three studies. Since IL12B encodes the common IL-12p40 subunit of IL-12 and IL-23, we individually genotyped 17 SNPs in the genes encoding the other chains of these cytokines (IL12A and IL23A) and their receptors (IL12RB1, IL12RB2, and IL23R). Haplotype analyses identified two IL23R missense SNPs that together mark a common psoriasis-associated haplotype in all three studies (OR(common) 1.44, Pcomb=3.13x10(-6)). Individuals homozygous for both the IL12B and the IL23R predisposing haplotypes have an increased risk of disease (OR(common) 1.66, Pcomb=1.33x10(-8)). These data, and the previous observation that administration of an antibody specific for the IL-12p40 subunit to patients with psoriasis is highly efficacious, suggest that these genes play a fundamental role in psoriasis pathogenesis.
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- 2007
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25. Celecoxib inhibits meningioma tumor growth in a mouse xenograft model.
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Ragel BT, Jensen RL, Gillespie DL, Prescott SM, and Couldwell WT
- Subjects
- Animals, Apoptosis, Celecoxib, Cyclooxygenase 2 metabolism, Factor VIII metabolism, Humans, Immunoenzyme Techniques, In Situ Nick-End Labeling, Ki-67 Antigen metabolism, Meningeal Neoplasms enzymology, Meningeal Neoplasms pathology, Meningioma enzymology, Meningioma pathology, Mice, Mice, Nude, Survival Rate, Tumor Cells, Cultured, Vascular Endothelial Growth Factor A metabolism, Xenograft Model Antitumor Assays, Cyclooxygenase Inhibitors therapeutic use, Meningeal Neoplasms prevention & control, Meningioma prevention & control, Pyrazoles therapeutic use, Sulfonamides therapeutic use
- Abstract
Background: Treatments for recurrent meningiomas are limited. We previously demonstrated universal expression of COX-2 in meningiomas and dose-dependent growth inhibition in vitro with celecoxib, a COX-2 inhibitor. We therefore tested the effects of celecoxib on meningioma growth in a mouse xenograft model., Methods: Meningioma cell lines (IOMM-Lee, CH157-MN, WHO grade I primary cultured tumor) were transplanted into flanks of nude mice fed mouse chow with celecoxib at varying concentrations (0, 500, 1000, 1500 ppm) ad libitum. Tumors were measured biweekly and processed for MIB-1, Factor VIII, COX-2, and VEGF, and assayed with transferase-mediated dUTP-biotin nick-end labeling (TUNEL)., Results: Celecoxib reduced growth of mean tumor volume by 66% (P < .05), 25% (P > .05), and 65% (P < .05) compared with untreated controls in IOMM-Lee, CH157-MN, and benign tumors, respectively. IOMM-Lee tumors removed from celecoxib treatment regained a growth rate similar to the control. Blood vessel density decreased and apoptotic cells increased in treated flank tumors. Diminished COX-2 expression and VEGF were observed in treated IOMM-Lee tumors. Mean plasma celecoxib levels were 845, 1540, and 2869 ng/mL, for low-, medium-, and high-dose celecoxib, respectively., Conclusions: Celecoxib inhibits meningioma growth in vivo at plasma levels achievable in humans. Celecoxib-treated tumors were less vascular with increased apoptosis. IOMM-Lee tumors treated with celecoxib showed decreased COX-2 and VEGF expression. COX-2 inhibitors may have a role in the treatment of recurrent meningiomas., ((c) 2007 American Cancer Society.)
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- 2007
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26. The role of cyclooxygenase-2 and prostaglandins in colon cancer.
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Eisinger AL, Prescott SM, Jones DA, and Stafforini DM
- Subjects
- Adenomatous Polyposis Coli Protein physiology, Animals, Dinoprostone physiology, Gene Expression Regulation, Neoplastic, Genes, APC physiology, Humans, Up-Regulation, Wnt Proteins physiology, beta Catenin physiology, Colonic Neoplasms physiopathology, Cyclooxygenase 2 physiology, Prostaglandins physiology, Signal Transduction physiology
- Abstract
The temporal association between loss of function of the tumor suppressor adenomatous polyposis coli (APC) and overexpression of cyclooxygenase 2 (COX-2) has been demonstrated in vivo and has led to the hypothesis that APC regulates COX-2 expression. This could potentially occur through a variety of mechanisms including the well-characterized ability of APC to negatively regulate Wnt signaling and decrease expression of target genes. However, recent findings suggest that the products of COX-2 elicit effects that occur upstream of the beta-catenin/TCF/LEF pathway. This review will focus on the regulation of COX-2 by APC and the interplay between COX-2 and the Wnt signaling pathway.
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- 2007
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27. Diacylglycerol kinase delta regulates protein kinase C and epidermal growth factor receptor signaling.
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Crotty T, Cai J, Sakane F, Taketomi A, Prescott SM, and Topham MK
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- Animals, Cells, Cultured, Diacylglycerol Kinase genetics, Diglycerides metabolism, Enzyme Activation, ErbB Receptors genetics, Female, Gene Deletion, Humans, Intercellular Signaling Peptides and Proteins genetics, Intercellular Signaling Peptides and Proteins metabolism, Isoenzymes genetics, JNK Mitogen-Activated Protein Kinases metabolism, Keratinocytes cytology, Keratinocytes physiology, Mice, Mice, Inbred C57BL, Mice, Knockout, Phenotype, Phosphorylation, Protein Kinase C genetics, Threonine metabolism, Diacylglycerol Kinase metabolism, ErbB Receptors metabolism, Isoenzymes metabolism, Protein Kinase C metabolism, Signal Transduction physiology
- Abstract
Diacylglycerol kinases (DGKs) phosphorylate diacylglycerol (DAG) to terminate its signaling. To study DGKdelta, we disrupted its gene in mice and found that DGKdelta deficiency reduced EGF receptor (EGFR) protein expression and activity. Similar to EGFR knockout mice, DGKdelta-deficient pups were born with open eyelids and died shortly after birth. PKCs are activated by DAG and phosphorylate EGFR to reduce its expression and activity. We found DAG accumulation, increased threonine phosphorylation of EGFR, enhanced phosphorylation of other PKC substrates, and increased PKC autophosphorylation in DGKdelta knockout cells, indicating that DGKdelta regulates EGFR by modulating PKC signaling.
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- 2006
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28. Expression of COX-2 in platelet-monocyte interactions occurs via combinatorial regulation involving adhesion and cytokine signaling.
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Dixon DA, Tolley ND, Bemis-Standoli K, Martinez ML, Weyrich AS, Morrow JD, Prescott SM, and Zimmerman GA
- Subjects
- 3' Untranslated Regions genetics, Active Transport, Cell Nucleus physiology, Antigens, Surface metabolism, Blood Platelets cytology, Cell Adhesion genetics, Cell Adhesion physiology, Cell Communication genetics, Cytokines pharmacology, Dinoprostone metabolism, ELAV Proteins, ELAV-Like Protein 1, Extracellular Signal-Regulated MAP Kinases metabolism, Gene Expression Regulation, Enzymologic genetics, Humans, Interleukin 1 Receptor Antagonist Protein pharmacology, Interleukin-1beta metabolism, Interleukin-1beta pharmacology, Monocytes cytology, NF-kappa B metabolism, P-Selectin pharmacology, Platelet Activation physiology, Poly(A)-Binding Proteins metabolism, RNA Stability drug effects, RNA-Binding Proteins metabolism, T-Cell Intracellular Antigen-1, Thrombin pharmacology, Transfection, U937 Cells, p38 Mitogen-Activated Protein Kinases metabolism, Blood Platelets metabolism, Cell Communication physiology, Cyclooxygenase 2 genetics, Cytokines metabolism, Membrane Proteins genetics, Monocytes metabolism, Signal Transduction physiology
- Abstract
Tight regulation of COX-2 expression is a key feature controlling eicosanoid production in atherosclerosis and other inflammatory syndromes. Adhesive interactions between platelets and monocytes occur in these conditions and deliver specific signals that trigger inflammatory gene expression. Using a cellular model of monocyte signaling induced by activated human platelets, we identified the central posttranscriptional mechanisms that regulate timing and magnitude of COX-2 expression. Tethering of monocytes to platelets and to purified P-selectin, a key adhesion molecule displayed by activated platelets, induces NF-kappaB activation and COX-2 promoter activity. Nevertheless, COX-2 mRNA is rapidly degraded, leading to aborted protein synthesis. Time-dependent signaling of monocytes induces a second phase of transcript accumulation accompanied by COX-2 enzyme synthesis and eicosanoid production. Here, generation of IL-1beta, a proinflammatory cytokine, promoted stabilization of COX-2 mRNA by silencing of the AU-rich mRNA decay element (ARE) in the 3'-untranslated region (3'UTR) of the mRNA. Consistent with observed mRNA stabilization, activated platelets or IL-1beta treatment induced cytoplasmic accumulation and enhanced ARE binding of the mRNA stability factor HuR in monocytes. These findings demonstrate that activated platelets induce COX-2 synthesis in monocytes by combinatorial signaling to transcriptional and posttranscriptional checkpoints. These checkpoints may be altered in disease and therefore useful as targets for antiinflammatory intervention.
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- 2006
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29. The adenomatous polyposis coli tumor suppressor gene regulates expression of cyclooxygenase-2 by a mechanism that involves retinoic acid.
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Eisinger AL, Nadauld LD, Shelton DN, Peterson PW, Phelps RA, Chidester S, Stafforini DM, Prescott SM, and Jones DA
- Subjects
- Alternative Splicing, Animals, Base Sequence, Cell Line, Cell Line, Tumor, DNA Primers, Dinoprostone metabolism, Gene Expression Regulation, Enzymologic, Genes, APC, Humans, Morpholines, RNA, Messenger genetics, Wnt Proteins genetics, Zebrafish, beta Catenin physiology, Cyclooxygenase 2 genetics, Tretinoin physiology
- Abstract
Mutations in the adenomatous polyposis coli (APC) gene result in uncontrolled proliferation of intestinal epithelial cells and are associated with the earliest stages of colorectal carcinogenesis. Cyclooxygenase-2 (COX-2) is elevated in human colorectal cancers and plays an important role in colorectal tumorigenesis; however, the mechanisms by which APC mutations result in increased COX-2 expression remain unclear. We utilized APC mutant zebrafish and human cancer cells to investigate how APC modulates COX-2 expression. We report that COX-2 is up-regulated in APC mutant zebrafish because of a deficiency in retinoic acid biosynthesis. Treatment of both APC mutant zebrafish and human carcinoma cell lines with retinoic acid significantly reduces COX-2 expression. Retinoic acid regulates COX-2 levels by a mechanism that involves participation of the transcription factor C/EBP-beta. APC mutant zebrafish express higher levels of C/EBP-beta than wild-type animals, and retinoic acid supplementation reduces C/EBP-beta expression to basal levels. Both morpholino knockdown of C/EBP-beta in APC mutant zebrafish and silencing of C/EBP-beta using small interfering RNA in HT29 colon cancer cells robustly decrease COX-2 expression. Our findings support a sequence of events in which mutations in APC result in impaired retinoic acid biosynthesis, elevated levels of C/EBP-beta, up-regulation of COX-2, increased prostaglandin E(2) accumulation, and activation of Wnt target genes.
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- 2006
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30. Exogenous platelet-activating factor acetylhydrolase reduces mortality in mice with systemic inflammatory response syndrome and sepsis.
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Gomes RN, Bozza FA, Amâncio RT, Japiassú AM, Vianna RC, Larangeira AP, Gouvêa JM, Bastos MS, Zimmerman GA, Stafforini DM, Prescott SM, Bozza PT, and Castro-Faria-Neto HC
- Subjects
- Animals, Anti-Bacterial Agents administration & dosage, Cytokines blood, Disease Models, Animal, Drug Therapy, Combination, Female, Humans, Male, Mice, Middle Aged, Systemic Inflammatory Response Syndrome blood, 1-Alkyl-2-acetylglycerophosphocholine Esterase administration & dosage, Platelet Activating Factor antagonists & inhibitors, Systemic Inflammatory Response Syndrome drug therapy
- Abstract
Current evidence indicates that dysregulation of the host inflammatory response to infectious agents is central to the mortality of patients with sepsis and in those with systemic inflammatory response syndrome. Strategies to block inflammatory mediators, often with complicated outcomes, are currently being investigated as new adjuvant therapies for sepsis. Here, we determined if administration of recombinant platelet-activating factor (rPAF)-acetylhydrolase (rPAF-AH), an enzyme that inactivates PAF and PAF-like lipids, protects mice from inflammatory injury and death after administration of lipopolysaccharide (LPS) or cecal ligation and puncture (CLP). Administration of rPAF-AH increased plasma PAF-AH activity and reduced mortality in both models. Treatment with rPAF-AH increased peritoneal fluid levels of monocyte chemoattractant protein 1/CCL-2 and decreased interleukin 6 and migration inhibitory factor levels after LPS administration or CLP. Administration of a broad-spectrum antibiotic together with rPAF-AH was more protective than single treatment with either of these agents. The combined treatment was associated with reduced interleukin 6 levels in mice subjected to CLP. We observed acute decreases in plasma PAF-AH activity in mice subjected to CLP or challenged with LPS and in human patients with sepsis. We conclude that alterations in the endogenous PAF-AH contribute to the pathophysiology of sepsis and that administration of exogenous rPAF-AH reduces inflammatory injury and mortality in models relevant to the clinical syndrome. Variations in endogenous PAF-AH activity may potentially account for variable responses to exogenous rPAF-AH in previous clinical trials. Serial measurements of plasma PAF-AH activity in murine models demonstrate dynamic regulation of the endogenous enzyme, potentially explaining the variations in human subjects.
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- 2006
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31. New roles for an old drug: inhibition of gene expression by dipyridamole in platelet-leukocyte aggregates.
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Weyrich AS, Kraiss LW, Prescott SM, and Zimmerman GA
- Subjects
- Coronary Disease drug therapy, Humans, P-Selectin drug effects, Dipyridamole therapeutic use, Gene Expression Regulation drug effects, Leukocytes drug effects, Platelet Aggregation drug effects, Platelet Aggregation Inhibitors therapeutic use
- Abstract
Interactions between platelets and leukocytes link critical thrombotic and inflammatory events that control an array of cardiovascular syndromes. In atherosclerosis alone, inducible gene expression in platelets and leukocytes modulates the initiation and development of vulnerable plaques that increase a patient's risk for acute coronary events. Interruption of gene expression pathways that are triggered when platelets adhere to leukocytes may be a new target for therapeutic intervention. Recent evidence indicates that dipyridamole, an old drug with a diverse history, differentially inhibits gene expression in platelet-leukocyte aggregates by exerting its effect at distinct molecular checkpoints.
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- 2006
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32. Release of free F2-isoprostanes from esterified phospholipids is catalyzed by intracellular and plasma platelet-activating factor acetylhydrolases.
- Author
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Stafforini DM, Sheller JR, Blackwell TS, Sapirstein A, Yull FE, McIntyre TM, Bonventre JV, Prescott SM, and Roberts LJ 2nd
- Subjects
- 1-Alkyl-2-acetylglycerophosphocholine Esterase chemistry, Acetates chemistry, Aldehydes chemistry, Animals, Bromides chemistry, Catalysis, DNA, Complementary metabolism, Humans, Hydrolysis, Isoprostanes chemistry, Kinetics, Lipoproteins chemistry, Mice, Mice, Transgenic, Ovalbumin metabolism, Oxidants chemistry, Oxidative Stress, Phosphatidylcholines chemistry, Phospholipases A2, Phospholipid Ethers chemistry, Potassium Compounds chemistry, Recombinant Proteins chemistry, Trachea metabolism, 1-Alkyl-2-acetylglycerophosphocholine Esterase metabolism, F2-Isoprostanes chemistry, Phospholipids chemistry
- Abstract
F2-isoprostanes are produced in vivo by nonenzymatic peroxidation of arachidonic acid esterified in phospholipids. Increased urinary and plasma F2-isoprostane levels are associated with a number of human diseases. These metabolites are regarded as excellent markers of oxidant stress in vivo. Isoprostanes are initially generated in situ, i.e. when the arachidonate precursor is esterified in phospholipids, and they are subsequently released in free form. Although the mechanism(s) responsible for the release of free isoprostanes after in situ generation in membrane phospholipids is, for the most part, unknown, this process is likely mediated by phospholipase A2 activity(ies). Here we reported that human plasma contains an enzymatic activity that catalyzes this reaction. The activity associates with high density and low density lipoprotein and comigrates with platelet-activating factor (PAF) acetylhydrolase on KBr density gradients. Plasma samples from subjects deficient in PAF acetylhydrolase do not release F2-isoprostanes from esterified precursors. The intracellular PAF acetylhydrolase II, which shares homology to the plasma enzyme, also catalyzes this reaction. We found that both the intracellular and plasma PAF acetylhydrolases have high affinity for esterified F2-isoprostanes. However, the rate of esterified F2-isoprostane hydrolysis is much slower compared with the rate of hydrolysis of other substrates utilized by these enzymes. Studies using PAF acetylhydrolase transgenic mice indicated that these animals have a higher capacity to release F2-isoprostanes compared with nontransgenic littermates. Our results suggested that PAF acetylhydrolases play key roles in the hydrolysis of F2-isoprostanes esterified on phospholipids in vivo.
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- 2006
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33. Classification of venous thromboembolism (VTE). The clot is hot: inflammation, myeloid leukocytes, and venous thromboembolism.
- Author
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Prescott SM, Weyrich AS, and Zimmerman GA
- Subjects
- Animals, Arteriosclerosis blood, Blood Coagulation physiology, Humans, Inflammation blood, Leukocytes physiology, Risk Factors, Thromboembolism blood, Thromboembolism diagnosis, Venous Thrombosis blood, Venous Thrombosis diagnosis, Thromboembolism classification, Venous Thrombosis classification
- Published
- 2005
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34. Ubiquitous expression of cyclooxygenase-2 in meningiomas and decrease in cell growth following in vitro treatment with the inhibitor celecoxib: potential therapeutic application.
- Author
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Ragel BT, Jensen RL, Gillespie DL, Prescott SM, and Couldwell WT
- Subjects
- Adult, Aged, Aged, 80 and over, Apoptosis, Blotting, Western, Celecoxib, Cell Proliferation, Cyclooxygenase 2, Cyclooxygenase 2 Inhibitors, Dose-Response Relationship, Drug, Female, Humans, Immunohistochemistry, Male, Membrane Proteins, Meningeal Neoplasms pathology, Meningioma pathology, Middle Aged, Prostaglandin-Endoperoxide Synthases metabolism, Tumor Cells, Cultured, Cyclooxygenase Inhibitors pharmacology, Meningeal Neoplasms enzymology, Meningioma enzymology, Prostaglandin-Endoperoxide Synthases biosynthesis, Pyrazoles pharmacology, Sulfonamides pharmacology
- Abstract
Object: Meningiomas are the second most common symptomatic primary central nervous system tumor in adults. Findings of epidemiological studies link meningiomas with a history of head trauma, indicating a causal relationship between the inflammatory response and meningioma tumorigenesis. Cyclooxygenase-2 (COX-2), an inducible inflammatory enzyme, converts arachidonic acid to prostaglandins, which have angiogenic, cell-proliferative, and antiapoptotic effects. The authors investigated COX-2 expression in meningiomas and the effects of celecoxib, a COX-2 inhibitor, on meningioma cell growth in vitro., Methods: Four meningioma surgical specimens were immunohistochemically stained and graded (0 to 4) for COX-2. In addition, a Western blot analysis was performed to detect the presence of COX-2. Human meningioma cells grown in cell culture were treated with vehicle or celecoxib (0.25-1 mM). An immunohistochemical analysis of COX-2, a methylthiotetrazole cell proliferation assay, a TUNEL apoptosis assay, and a Western blot analysis for the proapoptotic protein BAX were performed in vitro. One hundred eleven (87%) of 128 benign meningiomas and six (86%) of seven atypical meningiomas displayed a high COX-2 immunoreactivity (Grade 4 staining). In the Western blot analysis all four surgical specimens (100%) stained positive for a 70-kD band consistent with COX-2. Celecoxib inhibited cell growth in a dose-dependent fashion and induced apoptosis by Day 2, with no change noted in the expression of the BAX protein., Conclusions: The COX-2 enzyme is universally expressed in meningiomas. Celecoxib inhibits meningioma growth in vitro in a dose-dependent fashion, with evidence of apoptosis. Inhibitors of COX-2 may have a role in the treatment of recurrent meningiomas.
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- 2005
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35. Association between 5-lipoxygenase expression and plaque instability in humans.
- Author
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Cipollone F, Mezzetti A, Fazia ML, Cuccurullo C, Iezzi A, Ucchino S, Spigonardo F, Bucci M, Cuccurullo F, Prescott SM, and Stafforini DM
- Subjects
- Acute Disease, Aged, Brain Ischemia immunology, Brain Ischemia metabolism, Brain Ischemia pathology, Carotid Artery Diseases immunology, Cells, Cultured, Collagen metabolism, Female, Humans, Leukotriene B4 metabolism, Macrophages metabolism, Macrophages pathology, Male, Matrix Metalloproteinase 2 metabolism, Matrix Metalloproteinase 9 metabolism, Rupture, Signal Transduction physiology, Vasculitis, Central Nervous System immunology, Vasculitis, Central Nervous System metabolism, Vasculitis, Central Nervous System pathology, Arachidonate 5-Lipoxygenase metabolism, Carotid Artery Diseases metabolism, Carotid Artery Diseases pathology
- Abstract
Objective: The participation of 5-lipoxygenase (5-LO) in the development of atherosclerosis has been suggested by recent studies. However, a role for 5-LO as a modulator of atherosclerotic plaque instability has not been previously reported in humans. Thus, the aims of this study was to analyze the expression of 5-LO in human carotid plaques and to investigate the mechanism by which this enzyme could lead to plaque instability and rupture., Methods and Results: We obtained atherosclerotic plaques from 60 patients undergoing carotid endarterectomy. We divided the plaques into symptomatic and symptomatic according to clinical evidence of plaque instability. Clinical evidence of plaque instability was provided by the assessment of recent ischemic symptoms attributable to the stenosis and by the presence of ipsilateral cerebral lesion(s) determined by computed tomography. Plaques were analyzed for CD68+ macrophages, CD3+ T cells, alpha-actin+ smooth muscle cells, 5-LO, cyclooxygenase 2, matrix metalloproteinase (MMP)-2, and MMP-9 by immunohistochemical, immunoblotting, and densitometric analyses. MMP activity was assessed by zymography. Leukotriene (LT) B4 and collagen were quantified by ELISA and Sirius red polarization, respectively. The percentage of macrophage-rich and T-cell-rich areas was larger in symptomatic compared with asymptomatic patients (25+/-6% versus 8+/-4%, P<0.0001, and 74+/-17 versus 18+/-4 cell/mm2, P<0.003). 5-LO expression was higher in symptomatic compared with asymptomatic plaques (24+/-4% versus 6+/-3%, P<0.0001) and was associated with increased MMP-2 and MMP-9 expression (27+/-4% versus 7+/-3%, P<0.0001, and 29+/-5% versus 8+/-2%, P<0.0001) and activity and with decreased collagen content (6.9+/-2.4% versus 17.8+/-3.1%, P<0.01). Immunofluorescence showed that 5-LO and MMPs colocalize in activated macrophages. Notably, higher 5-LO in symptomatic plaques correlated with increased LTB4 production (18.15+/-3.56 versus 11.27+/-3.04 ng/g tissue, P<0.0001)., Conclusions: The expression of 5-LO is elevated in symptomatic compared with asymptomatic plaques and is associated with acute ischemic syndromes, possibly through the generation of LTB4, subsequent MMP biosynthesis, and plaque rupture.
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- 2005
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36. Fish oil fix.
- Author
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Prescott SM and Stenson WF
- Subjects
- Animals, Eicosapentaenoic Acid pharmacology, Eicosapentaenoic Acid physiology, Humans, Inflammation physiopathology, Anti-Inflammatory Agents pharmacology, Eicosapentaenoic Acid analogs & derivatives, Fish Oils pharmacology, Inflammation drug therapy
- Published
- 2005
- Full Text
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37. Diacylglycerol kinase iota regulates Ras guanyl-releasing protein 3 and inhibits Rap1 signaling.
- Author
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Regier DS, Higbee J, Lund KM, Sakane F, Prescott SM, and Topham MK
- Subjects
- Animals, Blotting, Southern, Blotting, Western, Cell Line, DNA Primers, Diacylglycerol Kinase genetics, Diglycerides metabolism, Enzyme Activation physiology, Immunoprecipitation, Mice, Mice, Knockout, Mice, Transgenic, Mutagenesis, Site-Directed, Plasmids genetics, Transfection, Diacylglycerol Kinase metabolism, Neoplasms, Experimental metabolism, Signal Transduction physiology, rap1 GTP-Binding Proteins metabolism, ras Guanine Nucleotide Exchange Factors metabolism
- Abstract
To study the physiological function of diacylglycerol (DAG) kinase iota (DGKiota), which converts DAG to phosphatidic acid, we deleted this gene in mice. In contrast to previous studies showing that DGK isoforms decrease Ras activity, signaling downstream of Ras in embryonic fibroblasts was significantly reduced in cells lacking DGKiota. DGKs regulate Ras signaling by attenuating the function of the DAG-dependent Ras guanyl nucleotide-releasing proteins (RasGRPs). We tested whether DGKiota inhibited the four known RasGRPs and found that it inhibited only RasGRP3. In addition to activating Ras, RasGRP3 also activates Rap1, which in some cases can antagonize the function of Ras. We demonstrate that DGKiota bound to RasGRP3 and inhibited its activation of Rap1 by metabolizing DAG. This inhibition consequently affected Ras signaling. We tested the physiological consequence of deleting DGKiota by crossing wild-type or DGKiota-deficient mice with mice carrying a v-Ha-Ras transgene, and then we assessed tumor formation. We observed significantly fewer tumors in DGKiota-deficient mice. Because Rap1 can antagonize the function of Ras, our data are consistent with a model in which DGKiota regulates RasGRP3 with a predominant effect on Rap1 activity. Additionally, we found that DGKzeta, which is structurally similar to DGKiota, inhibited RasGRPs 1, 3, and 4 and predominantly affected Ras signaling. Thus, type IV DGKs regulate RasGRPs, but the downstream effects differ depending on the DGK.
- Published
- 2005
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38. Regulating inflammation through the anti-inflammatory enzyme platelet-activating factor-acetylhydrolase.
- Author
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Castro Faria Neto HC, Stafforini DM, Prescott SM, and Zimmerman GA
- Subjects
- 1-Alkyl-2-acetylglycerophosphocholine Esterase chemistry, 1-Alkyl-2-acetylglycerophosphocholine Esterase genetics, Animals, Gene Expression Regulation, Phospholipases A2, Platelet Activating Factor chemistry, Polymorphism, Genetic, 1-Alkyl-2-acetylglycerophosphocholine Esterase physiology, Blood Platelets enzymology, Inflammation metabolism, Platelet Activating Factor physiology
- Abstract
Platelet-activating factor (PAF) is one of the most potent lipid mediators involved in inflammatory events. The acetyl group at the sn-2 position of its glycerol backbone is essential for its biological activity. Deacetylation induces the formation of the inactive metabolite lyso-PAF. This deacetylation reaction is catalyzed by PAF-acetylhydrolase (PAF-AH), a calcium independent phospholipase A2 that also degrades a family of PAF-like oxidized phospholipids with short sn-2 residues. Biochemical and enzymological evaluations revealed that at least three types of PAF-AH exist in mammals, namely the intracellular types I and II and a plasma type. Many observations indicate that plasma PAF AH terminates signals by PAF and oxidized PAF-like lipids and thereby regulates inflammatory responses. In this review, we will focus on the potential of PAF-AH as a modulator of diseases of dysregulated inflammation.
- Published
- 2005
- Full Text
- View/download PDF
39. Dipyridamole selectively inhibits inflammatory gene expression in platelet-monocyte aggregates.
- Author
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Weyrich AS, Denis MM, Kuhlmann-Eyre JR, Spencer ED, Dixon DA, Marathe GK, McIntyre TM, Zimmerman GA, and Prescott SM
- Subjects
- Anti-Inflammatory Agents, Non-Steroidal pharmacology, Aspirin pharmacology, Blood Platelets physiology, Cell Aggregation, Cell Communication drug effects, Chemokine CCL2 biosynthesis, Chemokine CCL2 genetics, Gene Expression drug effects, Humans, Matrix Metalloproteinase 9 biosynthesis, Matrix Metalloproteinase 9 genetics, Monocytes immunology, Protein Biosynthesis, RNA, Messenger metabolism, Blood Platelets drug effects, Dipyridamole pharmacology, Inflammation Mediators metabolism, Monocytes drug effects, Platelet Aggregation Inhibitors pharmacology
- Abstract
Background: Drugs that simultaneously decrease platelet function and inflammation may improve the treatment of cardiovascular disorders. Here, we determined whether dipyridamole and aspirin, a combination therapy used to prevent recurrent stroke, regulates gene expression in platelet-monocyte inflammatory model systems., Methods and Results: Human platelets and monocytes were pretreated with dipyridamole, aspirin, or both inhibitors. The cells were stimulated with thrombin or activated by adhesion to collagen, and gene expression was measured in the target monocytes. Thrombin-stimulated platelets increased monocyte chemotactic protein-1 (MCP-1) expression by monocytes. Dipyridamole but not aspirin attenuated nuclear translocation of NF-kappaB and blocked the synthesis of MCP-1 at the transcriptional level. Dipyridamole delayed maximal synthesis of interleukin-8 but did not alter cyclooxygenase-2 accumulation. Adherence to collagen and platelets also increased the expression of matrix metalloproteinase-9 (MMP-9) in monocytes, a response that was inhibited by dipyridamole. In this case, however, dipyridamole did not block transcription or distribution of MMP-9 mRNA to actively translating polysomes, indicating that it regulates the expression of MMP-9 protein at a postinitiation stage of translation. Dipyridamole also blocked MCP-1 and MMP-9 generated by lipopolysaccharide-treated monocytes, indicating that at least part of its inhibitory action is unrelated to its antiplatelet properties., Conclusions: These results indicate that dipyridamole has selective antiinflammatory properties that may contribute to its actions in the secondary prevention of stroke.
- Published
- 2005
- Full Text
- View/download PDF
40. Antinociceptive effect of Nidularium procerum: a Bromeliaceae from the Brazilian coastal rain forest.
- Author
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Amendoeira FC, Frutuoso VS, Chedier LM, Pearman AT, Figueiredo MR, Kaplan MA, Prescott SM, Bozza PT, and Castro-Faria-Neto HC
- Subjects
- Acetic Acid, Administration, Oral, Analgesics administration & dosage, Analgesics therapeutic use, Animals, Anti-Inflammatory Agents, Non-Steroidal administration & dosage, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Bradykinin, Brazil, Dose-Response Relationship, Drug, Edema chemically induced, Edema prevention & control, Hot Temperature, Injections, Intraperitoneal, Lipopolysaccharides, Male, Pain chemically induced, Plant Extracts administration & dosage, Plant Extracts therapeutic use, Plant Leaves, Plant Roots, Pleurisy chemically induced, Pleurisy prevention & control, Rats, Rats, Wistar, Trees, Analgesics pharmacology, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Bromeliaceae, Pain prevention & control, Phytotherapy, Plant Extracts pharmacology
- Abstract
Nidularium procerum, a common plant of the Brazilian flora, has not yet been studied for its pharmacological properties. We report here that extracts of N. procerum show both analgesic and anti-inflammatory properties. Oral (p.o.) or intraperitoneal (i.p.) administration of an aqueous crude extract from leaves of N. procerum (LAE) inhibited the writhing reaction induced by acetic acid (ED50 value = 0.2 mg/kg body weight, i.p.) in a dose-dependent manner. This analgesic property was confirmed in rats using two different models of bradykinin-induced hyperalgesia; there was 75% inhibition of pain in the modified Hargreaves assay, and 100% inhibition in the classical Hargreaves assay. This potent analgesic effect was not blocked by naloxone, nor was it observed in the hot plate model, indicating that the analgesic effect is not associated with the activation of opioid receptors in the central nervous system. By contrast, we found that LAE (0.02 microg/ml) selectively inhibited prostaglandin E2 production by cyclooxygenase (COX)-2, but not COX-1, which is a plausible mechanism for the analgesic effect. A crude methanol extract from the leaves also showed similar analgesic activity. An identical extract from the roots of N. procerum did not, however, block acetic acid-induced writhes, indicating that the analgesic compounds are concentrated in the leaves. Finally, we found that LAE inhibited an inflammatory reaction induced by lipopolysaccharide in the pleural cavity of mice.
- Published
- 2005
- Full Text
- View/download PDF
41. Diacylglycerol kinases.
- Author
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Luo B, Regier DS, Prescott SM, and Topham MK
- Subjects
- Animals, Diacylglycerol Kinase genetics, Multigene Family, Phosphatidic Acids biosynthesis, Phosphatidic Acids metabolism, Protein Transport, Signal Transduction, Substrate Specificity, Diacylglycerol Kinase chemistry, Diacylglycerol Kinase metabolism
- Abstract
Diacylglycerol kinases (DGKs) phosphorylate diacylglycerol to form phosphatidic acid. In most cases, members of this large family of enzymes appear to bind and regulate proteins activated by either diacylglycerol or phosphatidic acid. Proteins that appear to be regulated, in part, by DGKs include protein kinase Cs, RasGRPs, and phosphatidylinositol kinases. By modulating the activity of these proteins, DGKs potentially affect a number of biological events including-but likely not limited to-cell growth, neuronal transmission, and cytoskeleton remodeling.
- Published
- 2004
- Full Text
- View/download PDF
42. The p38 MAPK pathway mediates transcriptional activation of the plasma platelet-activating factor acetylhydrolase gene in macrophages stimulated with lipopolysaccharide.
- Author
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Wu X, Zimmerman GA, Prescott SM, and Stafforini DM
- Subjects
- 1-Alkyl-2-acetylglycerophosphocholine Esterase metabolism, Animals, Cell Line, Humans, Inflammation etiology, Inflammation metabolism, Lipopolysaccharides pharmacology, Macrophage Activation drug effects, Mice, Transcriptional Activation drug effects, 1-Alkyl-2-acetylglycerophosphocholine Esterase genetics, Macrophage Activation genetics, Macrophages physiology, Transcriptional Activation physiology, p38 Mitogen-Activated Protein Kinases physiology
- Abstract
Administration of lipopolysaccharide (LPS) to experimental animals results in the up-regulation of expression of the plasma form of platelet-activating factor acetylhydrolase (PAF AH) in tissue macrophages. To investigate the mechanism underlying induction of PAF AH by LPS we used murine RAW264.7 and human THP-1 macrophages as model systems. We found that the p38 mitogen-activated protein kinase (p38 MAPK) pathway mediates transcriptional activation of the PAF AH gene through the participation of nucleotides -68/-316 relative to the transcriptional initiation site. This promoter region spans two Sp1/Sp3 binding sites (SP-A and SP-B) and is necessary and sufficient for the observed effect. Disruption of these Sp binding sites significantly reduces promoter activity in LPS-stimulated cells. The ability of LPS to induce transcriptional activation of PAF AH is not due to enhanced Sp1/Sp3 binding to the promoter but involves enhanced transactivation function of Sp1 via p38 MAPK activation. These studies characterize the mechanism by which LPS modulates expression of PAF AH at the transcriptional level, and they have important implications for our understanding of responses that occur during the development of LPS-mediated inflammatory diseases.
- Published
- 2004
- Full Text
- View/download PDF
43. Diacylglycerol kinase zeta regulates phosphatidylinositol 4-phosphate 5-kinase Ialpha by a novel mechanism.
- Author
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Luo B, Prescott SM, and Topham MK
- Subjects
- Actins metabolism, Cells, Cultured, Cytoskeleton metabolism, Humans, Phosphatidylinositol 4,5-Diphosphate metabolism, Phosphorylation, Thrombin pharmacology, Diacylglycerol Kinase metabolism, Phosphatidic Acids metabolism, Phosphotransferases (Alcohol Group Acceptor) metabolism
- Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP2) plays an important role during actin polymerization and is produced by the type I phosphatidylinositol 4-phosphate 5-kinases (PIP5KI), which are activated by phosphatidic acid (PA). As diacylglycerol kinases (DGKs) generate PA by phosphorylating diacylglycerol (DAG), we investigated whether DGKs were involved in controlling PIP2 levels by regulating PIP5KI activity. Here we show that expression of DGKzeta significantly enhances PIP5KIalpha activity in thrombin-stimulated HEK293 cells, and DGK activity is required for this stimulation. We also observed that DGKzeta co-immunoprecipitated and co-localized with PIP5KIalpha, suggesting that they reside in a regulated signaling complex. To explore the role of DGKzeta in actin polymerization, we examined the subcellular distribution of DGKzeta, PIP5KIalpha and actin, and found that these proteins co-localized with actin in lamellipodial protrusions. Supporting that PIP5KIalpha regulation occurs at the sites of actin polymerization, we found that PIP2 also accumulated in the actin-rich regions of lamellipodia. Significantly, in wounding assays, DGKzeta, PIP5KIalpha and PIP2 accumulated at the leading edge of migrating A172 cells, where massive actin polymerization is known to occur. Combined, these data support a novel function for DGKzeta: by generating PA, it stimulates PIP5KIalpha activity to increase local PIP2, which regulates actin polymerization.
- Published
- 2004
- Full Text
- View/download PDF
44. Regulation of COX-2 transcription in a colon cancer cell line by Pontin52/TIP49a.
- Author
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Carlson ML, Wilson ET, and Prescott SM
- Subjects
- ATPases Associated with Diverse Cellular Activities, Carrier Proteins genetics, Cell Line, Tumor, Cell Transformation, Neoplastic genetics, Cell Transformation, Neoplastic metabolism, Cell Transformation, Neoplastic pathology, Colonic Neoplasms pathology, Cyclooxygenase 2, DNA Helicases genetics, Humans, In Situ Hybridization, Membrane Proteins, RNA, Messenger genetics, RNA, Messenger metabolism, Carrier Proteins metabolism, Colonic Neoplasms enzymology, Colonic Neoplasms genetics, DNA Helicases metabolism, Gene Expression Regulation, Enzymologic, Gene Expression Regulation, Neoplastic, Prostaglandin-Endoperoxide Synthases genetics, Transcription, Genetic genetics
- Abstract
Cyclooxygenase-2 (COX-2) is expressed early in colon carcinogenesis and is known to play a crucial role in the progress of the disease. Here we show that the regulation of the expression of this enzyme in a colon cancer cell line, and in patients, is associated with overexpression of the Wnt pathway-associated proteins, Pontin52/TIP49a and LEF-1. Recently shown to be essential for transformation via the c-Myc pathway, Pontin52/TIP49a promotes COX-2 expression in tissue culture and is overexpressed in colon cancer tissue, co-localizing with COX-2 expression in transformed tissue, relative to paired normal tissue.
- Published
- 2003
- Full Text
- View/download PDF
45. Platelet-activating factor, a pleiotrophic mediator of physiological and pathological processes.
- Author
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Stafforini DM, McIntyre TM, Zimmerman GA, and Prescott SM
- Subjects
- Acetyltransferases metabolism, Animals, Humans, Inflammation metabolism, Phospholipases A metabolism, Phospholipases A2, Platelet Membrane Glycoproteins metabolism, Receptors, G-Protein-Coupled metabolism, Signal Transduction, Platelet Activating Factor physiology
- Abstract
Platelet-activating factor (PAF) is a potent proinflammatory phospholipid with diverse pathological and physiological effects. This bioactive phospholipid mediates processes as diverse as wound healing, physiological inflammation, apoptosis, angiogenesis, reproduction and long-term potentiation. Recent progress has demonstrated the participation of MAP kinase signaling pathways as modulators of the two critical enzymes, phospholipase A2 and acetyltransferase, involved in the remodeling pathway of PAF biosynthesis. The unregulated production of structural analogs of PAF by non-specific oxidative reactions has expanded this superfamily of signaling molecules to include "PAF-like" lipids whose mode of action is identical to that of authentic PAF. The action of members of this family is mediated by the PAF receptor, a G protein-coupled membrane-spanning molecule that can engage multiple signaling pathways in various cell types. Inappropriate activation of this signaling pathway is associated with many diseases in which inflammation is thought to be one of the underlying features. Inactivation of all members of the PAF superfamily occurs by a unique class of enzymes, the PAF acetylhydrolases, that have been characterized at the molecular level and that terminate signals initiated by both regulated and unregulated PAF production.
- Published
- 2003
- Full Text
- View/download PDF
46. Molecular characterization of the constitutive expression of the plasma platelet-activating factor acetylhydrolase gene in macrophages.
- Author
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Wu X, McIntyre TM, Zimmerman GA, Prescott SM, and Stafforini DM
- Subjects
- 1-Alkyl-2-acetylglycerophosphocholine Esterase blood, 1-Alkyl-2-acetylglycerophosphocholine Esterase metabolism, 5' Flanking Region genetics, Animals, Base Sequence, Binding Sites genetics, Cell Line, Cloning, Molecular, DNA chemistry, DNA genetics, DNA metabolism, DNA-Binding Proteins metabolism, Electrophoretic Mobility Shift Assay, Gene Expression, Gene Expression Regulation, Humans, Luciferases genetics, Luciferases metabolism, Macrophages cytology, Mice, Molecular Sequence Data, Mutation, Oligonucleotide Probes genetics, Oligonucleotide Probes metabolism, Promoter Regions, Genetic genetics, Protein Binding, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Sequence Analysis, DNA, Sequence Homology, Nucleic Acid, Sp1 Transcription Factor metabolism, Sp3 Transcription Factor, Transcription Factors metabolism, Transcription, Genetic, 1-Alkyl-2-acetylglycerophosphocholine Esterase genetics, Macrophages metabolism
- Abstract
Plasma platelet-activating factor acetylhydrolase (PAF-AH) is a phospholipase that inactivates platelet-activating factor (PAF) and PAF-like lipids to generate products with little or no biological activity. The levels of circulating PAF-AH correlate with several disease syndromes. We previously reported that mediators of inflammation regulate the expression of the human PAF-AH gene at the transcriptional level. In the present paper, we characterize the constitutive expression of plasma PAF-AH using the mouse gene as a model system, and we report comparative results obtained using human and mouse promoter constructs. We first cloned, sequenced and analysed the promoter region of the murine plasma PAF-AH (mPAF-AH) gene and found that this gene lacks a canonical TATA box. We demonstrated that the cis -elements required for basal transcription are localized within the -316 to -68 bp region. In vitro band-shift and supershift assays showed that Sp1 and Sp3 transcription factors from RAW264.7 and J774A.1 macrophage nuclear extracts bound strongly to a distal GC-rich site within -278/-243 [specificity protein (Sp-A)] and to a proximal TC-rich motif within -150/-114 (Sp-B). In addition, we observed weak binding to a GA-rich site within -110/-82 (Sp-C). The regions containing Sp-B and Sp-C are highly conserved between the human and mouse genes. Forced expression of Sp1 or Sp3 in Sp-lacking Drosophila SL2 cells induced markedly the activity of the exogenous mPAF-AH promoter in a dose-dependent manner, and this induction was dependent on the presence of intact Sp-A and Sp-B. Interestingly, we found that the Sp1- and Sp3-associated DNA-binding activities increased during the maturation of primary human monocytes into macrophages in cell culture. These results demonstrate that Sp1 and Sp3 are key factors that contribute to the basal, constitutive transcription of the plasma PAF-AH gene in macrophages.
- Published
- 2003
- Full Text
- View/download PDF
47. Protein kinase C alpha phosphorylates and negatively regulates diacylglycerol kinase zeta.
- Author
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Luo B, Prescott SM, and Topham MK
- Subjects
- Binding Sites, Cell Division, Cell Line, Diglycerides metabolism, Humans, In Vitro Techniques, Myristoylated Alanine-Rich C Kinase Substrate, Phospholipase C gamma, Phosphorylation, Protein Kinase C-alpha, Protein Structure, Tertiary, Proteins metabolism, Recombinant Proteins metabolism, Signal Transduction, Tetradecanoylphorbol Acetate pharmacology, Type C Phospholipases metabolism, Diacylglycerol Kinase metabolism, Intracellular Signaling Peptides and Proteins, Membrane Proteins, Protein Kinase C metabolism
- Abstract
Diacylglycerol kinase (DGK) terminates diacylglycerol (DAG) signaling by phosphorylating DAG to produce phosphatidic acid, which also has signaling properties. Thus, precise control of DGK activity is essential for proper signal transduction. We demonstrated previously that a peptide corresponding to the myristoylated alanine-rich C kinase substrate (MARCKS) phosphorylation site domain (PSD) in DGK zeta was phosphorylated in vitro by an active fragment of protein kinase C (PKC). In the present study, we tested full-length DGK zeta and found that PKC alpha phosphorylated DGK zeta on serines within the MARCKS PSD in vitro and in vivo. DGK zeta also coimmunoprecipitated with PKC alpha, suggesting that they reside in a regulated signaling complex. We then tested whether phosphorylation affected DAG kinase activity. We found that a mutant (DGK zeta S/D) in which serines within the MARCKS PSD were altered to aspartates (to mimic phosphorylation) had lower activity compared with wild-type DGK zeta or a control mutant (DGK zeta S/N) in which the same serines were changed to asparagines. Furthermore, activation of PKC alpha by phorbol 12-myristate 13-acetate inhibited the activity of wild-type DGK zeta, but not DGK zeta S/D, in human embryonic kidney 293 cells. These results suggest that by phosphorylating the MARCKS PSD, PKC alpha attenuates DGK zeta activity. Supporting this, we found that cells expressing DGK zeta S/D had higher DAG levels and grew more rapidly compared with cells expressing DGK zeta S/N that could not be phosphorylated. Taken together, these results indicate that PKC alpha phosphorylates DGK zeta in cells, and this phosphorylation inhibits its kinase activity to remove cellular DAG, thereby affecting cell growth.
- Published
- 2003
- Full Text
- View/download PDF
48. Synergism between platelet-activating factor-like phospholipids and peroxisome proliferator-activated receptor gamma agonists generated during low density lipoprotein oxidation that induces lipid body formation in leukocytes.
- Author
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de Assis EF, Silva AR, Caiado LF, Marathe GK, Zimmerman GA, Prescott SM, McIntyre TM, Bozza PT, and de Castro-Faria-Neto HC
- Subjects
- Animals, Arachidonate 5-Lipoxygenase metabolism, Arachidonate 5-Lipoxygenase physiology, Cyclooxygenase 2, Drug Synergism, Female, Humans, Isoenzymes metabolism, Leukocytes physiology, Lipoproteins, LDL administration & dosage, Lipoproteins, LDL pharmacology, Macrophages, Peritoneal metabolism, Male, Membrane Proteins, Mice, Oxidation-Reduction, Peroxisomes enzymology, Peroxisomes physiology, Phospholipids metabolism, Platelet Activating Factor administration & dosage, Platelet Activating Factor metabolism, Pleural Cavity cytology, Prostaglandin-Endoperoxide Synthases metabolism, Receptors, Cytoplasmic and Nuclear metabolism, Thoracic Cavity, Transcription Factors metabolism, Inclusion Bodies metabolism, Leukocytes metabolism, Lipoproteins, LDL metabolism, Peroxisomes metabolism, Platelet Activating Factor physiology, Receptors, Cytoplasmic and Nuclear agonists, Receptors, Cytoplasmic and Nuclear physiology, Transcription Factors agonists, Transcription Factors physiology
- Abstract
Oxidized low density lipoprotein (LDL) has an important proinflammatory role in atherogenesis. In this study, we investigated the ability of oxidized LDL (oxLDL) and its phospholipid components to induce lipid body formation in leukocytes. Incubation of mouse peritoneal macrophages with oxidized, but not with native LDL led to lipid body formation within 1 h. This was blocked by platelet-activating factor (PAF) receptor antagonists or by preincubation of oxLDL with rPAF acetylhydrolase. HPLC fractions of phospholipids purified from oxLDL induced calcium flux in neutrophils as well as lipid body formation in macrophages. Injection of the bioactive phospholipid fractions or butanoyl and butenoyl PAF, a phospholipid previously shown to be present in oxLDL, into the pleural cavity of mice induced lipid body formation in leukocytes recovered after 3 h. The 5-lipoxygenase and cyclooxygenase-2 colocalized within lipid bodies formed after stimulation with oxLDL, bioactive phospholipid fractions, or butanoyl and butenoyl PAF. Lipid body formation was inhibited by 5-lipoxygenase antagonists, but not by cyclooxygenase-2 inhibitors. Azelaoyl-phosphatidylcholine, a peroxisome proliferator-activated receptor-gamma agonist in oxLDL phospholipid fractions, induced formation of lipid bodies at late time points (6 h) and synergized with suboptimal concentrations of oxLDL. We conclude that lipid body formation is an important proinflammatory effect of oxLDL and that PAF-like phospholipids and peroxisome proliferator-activated receptor-gamma agonists generated during LDL oxidation are important mediators in this phenomenon.
- Published
- 2003
- Full Text
- View/download PDF
49. Regulation of cyclooxygenase-2 expression by the translational silencer TIA-1.
- Author
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Dixon DA, Balch GC, Kedersha N, Anderson P, Zimmerman GA, Beauchamp RD, and Prescott SM
- Subjects
- Animals, Cyclooxygenase 2, Fibroblasts cytology, Fibroblasts metabolism, Humans, Isoenzymes genetics, Membrane Proteins genetics, Mice, Poly(A)-Binding Proteins, Prostaglandin-Endoperoxide Synthases genetics, Protein Binding, RNA, Messenger metabolism, RNA-Binding Proteins genetics, Silencer Elements, Transcriptional, T-Cell Intracellular Antigen-1, Tumor Cells, Cultured, Gene Expression Regulation, Enzymologic, Isoenzymes metabolism, Membrane Proteins metabolism, Prostaglandin-Endoperoxide Synthases metabolism, Protein Biosynthesis, Proteins, RNA Processing, Post-Transcriptional, RNA-Binding Proteins metabolism
- Abstract
The cyclooxygenase-2 (COX-2) enzyme catalyzes the rate-limiting step of prostaglandin formation in inflammatory states, and COX-2 overexpression plays a key role in carcinogenesis. To understand the mechanisms regulating COX-2 expression, we examined its posttranscriptional regulation mediated through the AU-rich element (ARE) within the COX-2 mRNA 3'-untranslated region (3'UTR). RNA binding studies, performed to identify ARE-binding regulatory factors, demonstrated binding of the translational repressor protein TIA-1 to COX-2 mRNA. The significance of TIA-1-mediated regulation of COX-2 expression was observed in TIA-1 null fibroblasts that produced significantly more COX-2 protein than wild-type fibroblasts. However, TIA-1 deficiency did not alter COX-2 transcription or mRNA turnover. Colon cancer cells demonstrated to overexpress COX-2 through increased polysome association with COX-2 mRNA also showed defective TIA-1 binding both in vitro and in vivo. These findings implicate that TIA-1 functions as a translational silencer of COX-2 expression and support the hypothesis that dysregulated RNA-binding of TIA-1 promotes COX-2 expression in neoplasia.
- Published
- 2003
- Full Text
- View/download PDF
50. Association of diacylglycerol kinase zeta with protein kinase C alpha: spatial regulation of diacylglycerol signaling.
- Author
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Luo B, Prescott SM, and Topham MK
- Subjects
- 3T3 Cells, Amino Acid Motifs physiology, Animals, Calcium-Binding Proteins, Catalytic Domain physiology, Diacylglycerol Kinase genetics, Glucosidases, Humans, Mice, Mutation physiology, Myristoylated Alanine-Rich C Kinase Substrate, Phosphoproteins genetics, Phosphoproteins metabolism, Phosphorylation, Protein Binding physiology, Protein Isoforms genetics, Protein Isoforms metabolism, Protein Kinase C genetics, Protein Kinase C-alpha, Rats, Diacylglycerol Kinase metabolism, Diglycerides metabolism, Eukaryotic Cells enzymology, Intracellular Signaling Peptides and Proteins, Membrane Proteins, Protein Kinase C metabolism, Signal Transduction physiology
- Abstract
Activation of PKC depends on the availability of DAG, a signaling lipid that is tightly and dynamically regulated. DAG kinase (DGK) terminates DAG signaling by converting it to phosphatidic acid. Here, we demonstrate that DGKzeta inhibits PKCalpha activity and that DGK activity is required for this inhibition. We also show that DGKzeta directly interacts with PKCalpha in a signaling complex and that the binding site in DGKzeta is located within the catalytic domain. Because PKCalpha can phosphorylate the myristoylated alanine-rich C-kinase substrate (MARCKS) motif of DGKzeta, we tested whether this modification could affect their interaction. Phosphorylation of this motif significantly attenuated coimmunoprecipitation of DGKzeta and PKCalpha and abolished their colocalization in cells, indicating that it negatively regulates binding. Expression of a phosphorylation-mimicking DGKzeta mutant that was unable to bind PKCalpha did not inhibit PKCalpha activity. Together, our results suggest that DGKzeta spatially regulates PKCalpha activity by attenuating local accumulation of signaling DAG. This regulation is impaired by PKCalpha-mediated DGKzeta phosphorylation.
- Published
- 2003
- Full Text
- View/download PDF
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