153 results on '"Bedi K"'
Search Results
2. Protamine Dosing for Heparin Reversal after Cardiopulmonary Bypass: A Double-blinded Prospective Randomized Control Trial Comparing Two Strategies.
- Author
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Jain P, Silva-De Las Salas A, Bedi K, Lamelas J, Epstein RH, and Fabbro M 2nd
- Subjects
- Humans, Double-Blind Method, Male, Female, Prospective Studies, Middle Aged, Aged, Dose-Response Relationship, Drug, Protamines administration & dosage, Cardiopulmonary Bypass methods, Heparin administration & dosage, Heparin Antagonists administration & dosage, Anticoagulants administration & dosage
- Abstract
Background: Drug shortages are a frequent challenge in current clinical practice. Certain drugs (e.g., protamine) lack alternatives, and inadequate supplies can limit access to services. Conventional protamine dosing uses heparin ratio-based calculations for heparin reversal after cardiopulmonary bypass and may result in excess protamine utilization and potential harm due to its intrinsic anticoagulation. This study hypothesized that a fixed 250-mg protamine dose would be comparable, as measured by the activated clotting time, to a 1:1 (1 mg for every 100 U) protamine-to-heparin ratio-based strategy for heparin reversal and that protamine would be conserved., Methods: In a single-center, double-blinded trial, consenting elective adult cardiac surgical patients without preexisting coagulopathy or ongoing anticoagulation and a calculated initial heparin dose greater than or equal to 27,500 U were randomized to receive, after cardiopulmonary bypass, protamine as a fixed dose (250 mg) or a ratio-based dose (1 mg:100 U heparin). The primary outcome was the activated clotting time after initial protamine administration, assessed by Student's t test. Secondary outcomes included total protamine, the need for additional protamine, and the cumulative 24-h chest tube output., Results: There were 62 and 63 patients in the fixed- and ratio-based dose groups, respectively. The mean postprotamine activated clotting time was not different between groups (-2.0 s; 95% CI, -7.2 to 3.3 s; P = 0.47). Less total protamine per case was administered in the fixed-dose group (-2.1 50-mg vials; 95% CI, -2.4 to -1.8; P < 0.0001). There was no difference in the cumulative 24-h chest tube output (difference, -77 ml; 95% CI, 220 to 65 ml; P = 0.28)., Conclusions: A 1:1 heparin ratio-based protamine dosing strategy compared to a fixed 250-mg dose resulted in the administration of a larger total dose of protamine but no difference in either the initial activated clotting time or the amount postoperative chest-tube bleeding., (Copyright © 2024 American Society of Anesthesiologists. All Rights Reserved.)
- Published
- 2025
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3. Aberrant BCAT1 expression augments MTOR activity and accelerates disease progression in chronic lymphocytic leukemia.
- Author
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Shao Q, Wykretowicz J, Hu N, Bedi K, Rizk M, Malek IA, Kumar S, Lombard DB, Shedden K, Scott D, and Malek SN
- Abstract
We performed gene expression profiling of mRNA/cDNA isolated from N = 117 flow sorted CLL. We detected aberrant expression of the metabolic enzyme branched chain amino acid transferase (BCAT1) in CLL with del17p/TP53mut. Through extensive validation, we confirmed the highly preferential expression of BCAT1 in CLL with del17p/TP53mut (66%) or trisomy 12 (77%). BCAT1 was not expressed in B cells isolated from normal human lymph nodes. The products of the bidirectional BCAT1 reaction, including leucine, acetyl-CoA, and alpha-ketoglutarate are known activators of MTOR. We measured an ~two-fold higher MTOR activity via normalized p-S6K levels in primary CLL with BCAT1 high versus absent expression before and after sIgM crosslinking. Through steady state metabolomics and heavy isotope metabolic tracing in primary CLL cells, we demonstrate that CLL cells are avid consumers of branched chain amino acids (BCAAs) and that BCAT1 in CLL engages in bidirectional substrate reactions. Of additional interest, CLL with aberrant BCAT1 expression were less sensitive to Venetoclax-induced apoptosis. Biologically, three CLL-derived cell lines with disruption of BCAT1 had substantially reduced growth ex vivo. Clinically, the expression of any detectable BCAT1 protein in CLL independently associated with shorter median survival (125 months versus 296 months; p < 0.0001), even after exclusion of del17p/TP53mut cases., Competing Interests: Competing interests Sami Malek owns stock in Abbvie. The other authors declared no conflicts., (© 2024. The Author(s).)
- Published
- 2024
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4. SGLT2 inhibitors activate pantothenate kinase in the human heart.
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Forelli N, Eaton D, Patel J, Bowman CE, Kawakami R, Kuznetsov IA, Li K, Brady C, Bedi K, Yang Y, Koya K, Megill E, Kanter DS, Smith LG, Bowman GR, Snyder N, Edwards J, Margulies K, and Arany Z
- Abstract
Inhibitors of sodium glucose cotransporter-2 (SGLT2i) demonstrate strong symptomatic and mortality benefits in the treatment of heart failure but appear to do so independently of SGLT2. The relevant pharmacologic target of SGLT2i remains unclear. We show here that SGLT2i directly activate pantothenate kinase 1 (PANK1), the rate-limiting enzyme that initiates the conversion of pantothenate (vitamin B5) to coenzyme-A (CoA), an obligate co-factor for all major pathways of fuel use in the heart. Using stable-isotope infusion studies, we show that SGLT2i promote pantothenate consumption, activate CoA synthesis, rescue decreased levels of CoA in human failing hearts, and broadly stimulate fuel use in ex vivo perfused human cardiac blocks from patients with heart failure. Furthermore, we show that SGLT2i bind to PANK1 directly at physiological concentrations and promote PANK1 enzymatic activity in assays with purified components. Novel in silico dynamic modeling identified the site of SGLT2i binding on PANK1 and indicated a mechanism of activation involving prevention of allosteric inhibition of PANK1 by acyl-CoA species. Finally, we show that inhibition of PANK1 prevents SGLT2i-mediated increased contractility of isolated adult human cardiomyocytes. In summary, we demonstrate robust and specific off-target activation of PANK1 by SGLT2i, promoting CoA synthesis and efficient fuel use in human hearts, providing a likely explanation for the remarkable clinical benefits of SGLT2i.
- Published
- 2024
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5. Isoform and pathway-specific regulation of post-transcriptional RNA processing in human cells.
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Bedi K, Magnuson B, Narayanan IV, McShane A, Ashaka M, Paulsen MT, Wilson TE, and Ljungman M
- Abstract
Steady-state levels of RNA transcripts are controlled by their rates of synthesis and degradation. Here we used nascent RNA Bru-seq and BruChase-seq to profile RNA dynamics across 16 human cell lines as part of ENCODE4 Deeply Profiled Cell Lines collection. We show that RNA turnover dynamics differ widely between transcripts of different genes and between different classes of RNA. Gene set enrichment analysis (GSEA) revealed that transcripts encoding proteins belonging to the same pathway often show similar turnover dynamics. Furthermore, transcript isoforms show distinct dynamics suggesting that RNA turnover is important in regulating mRNA isoform choice. Finally, splicing across newly made transcripts appears to be cooperative with either all or none type splicing. These data sets generated as part of ENCODE4 illustrate the intricate and coordinated regulation of RNA dynamics in controlling gene expression to allow for the precise coordination of cellular functions.
- Published
- 2024
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6. Characterizing nascent transcription patterns of PROMPTs, eRNAs, and readthrough transcripts in the ENCODE4 deeply profiled cell lines.
- Author
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McShane A, Narayanan IV, Paulsen MT, Ashaka M, Blinkiewicz H, Yang NT, Magnuson B, Bedi K, Wilson TE, and Ljungman M
- Abstract
Arising as co-products of canonical gene expression, transcription-associated lincRNAs, such as promoter upstream transcripts (PROMPTs), enhancer RNAs (eRNAs), and readthrough (RT) transcripts, are often regarded as byproducts of transcription, although they may be important for the expression of nearby genes. We identified regions of nascent expression of these lincRNA in 16 human cell lines using Bru-seq techniques, and found distinctly regulated patterns of PROMPT, eRNA, and RT transcription using the diverse biochemical approaches in the ENCODE4 deeply profiled cell lines collection. Transcription of these lincRNAs was influenced by sequence-specific features and the local or 3D chromatin landscape. However, these sequence and chromatin features do not describe the full spectrum of lincRNA expression variability we identify, highlighting the complexity of their regulation. This may suggest that transcription-associated lincRNAs are not merely byproducts, but rather that the transcript itself, or the act of its transcription, is important for genomic function.
- Published
- 2024
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7. Discovery adductomics provides a comprehensive portrait of tissue-, age- and sex-specific DNA modifications in rodents and humans.
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Guilbaud A, Ghanegolmohammadi F, Wang Y, Leng J, Kreymerman A, Gamboa Varela J, Garbern J, Elwell H, Cao F, Ricci-Blair EM, Liang C, Balamkundu S, Vidoudez C, DeMott MS, Bedi K, Margulies KB, Bennett DA, Palmer AA, Barkley-Levenson A, Lee RT, and Dedon PC
- Subjects
- Animals, Female, Humans, Male, Rats, Chromatography, Liquid methods, Rodentia, Tandem Mass Spectrometry methods, DNA chemistry, DNA Adducts genetics
- Abstract
DNA damage causes genomic instability underlying many diseases, with traditional analytical approaches providing minimal insight into the spectrum of DNA lesions in vivo. Here we used untargeted chromatography-coupled tandem mass spectrometry-based adductomics (LC-MS/MS) to begin to define the landscape of DNA modifications in rat and human tissues. A basis set of 114 putative DNA adducts was identified in heart, liver, brain, and kidney in 1-26-month-old rats and 111 in human heart and brain by 'stepped MRM' LC-MS/MS. Subsequent targeted analysis of these species revealed species-, tissue-, age- and sex-biases. Structural characterization of 10 selected adductomic signals as known DNA modifications validated the method and established confidence in the DNA origins of the signals. Along with strong tissue biases, we observed significant age-dependence for 36 adducts, including N2-CMdG, 5-HMdC and 8-Oxo-dG in rats and 1,N6-ϵdA in human heart, as well as sex biases for 67 adducts in rat tissues. These results demonstrate the potential of adductomics for discovering the true spectrum of disease-driving DNA adducts. Our dataset of 114 putative adducts serves as a resource for characterizing dozens of new forms of DNA damage, defining mechanisms of their formation and repair, and developing them as biomarkers of aging and disease., (© The Author(s) 2023. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2023
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8. Comparative evaluation of fracture resistance among conventional versus herbal irrigants in root canal treated teeth: In vitro study.
- Author
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Sinha DJ, Rani P, Vats S, Bedi K, Sharma N, and Manjiri HN
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- Humans, Epoxy Resins, Dental Pulp Cavity, Root Canal Obturation, Root Canal Preparation, Gutta-Percha, Sodium Hypochlorite therapeutic use, Root Canal Irrigants, Root Canal Filling Materials therapeutic use
- Abstract
To evaluate the efficacy of conventional irrigants and herbal extracts materials which helps to resist fracture of endodontically treated teeth. 75 maxillary human permanent incisor teeth instrumented using ProTaper rotary files till apical size(F4). Instrumented samples divided into 5 groups with n = 15 based on various irrigants used. Group I: normal saline, Group II: 5% sodium hypochlorite (NaOCl), Group III: 2% chlorohexidine, Group IV: 10% Azadirachta indica (neem extract) and Group V: 10% Ocimum sanctum (tulsi extract).After that, root canals were proceeded to be filled by using single gutta-percha cone and Sealapex sealer. Specimens were then prepared and loaded until root fracture occurred. Maximum mean flexural strength of dentin (fracture resistance) was obtained from group treated with 2% chlorohexidine and 10% neem extract. Least fracture resistance was observed with 5% NaOCl. Herbal irrigants can be used as an alternative to NaOCl as they exhibit high fracture resistance., (© 2023 Australian Society of Endodontology Inc.)
- Published
- 2023
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9. LSD1 promotes prostate cancer reprogramming by repressing TP53 signaling independently of its demethylase function.
- Author
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Kumaraswamy A, Duan Z, Flores D, Zhang C, Sehrawat A, Hu YM, Swaim OA, Rodansky E, Storck WK, Kuleape JA, Bedi K, Mannan R, Wang XM, Udager A, Ravikumar V, Bankhead A 3rd, Coleman I, Lee JK, Morrissey C, Nelson PS, Chinnaiyan AM, Rao A, Xia Z, Yates JA, and Alumkal JJ
- Subjects
- Humans, Male, Cell Line, Tumor, Histone Demethylases genetics, Signal Transduction genetics, Tumor Suppressor Protein p53 genetics, Tumor Suppressor Protein p53 metabolism, Adenocarcinoma genetics, Prostatic Neoplasms pathology
- Abstract
Lysine-specific demethylase 1 (LSD1) is a histone demethylase that promotes stemness and cell survival in cancers such as prostate cancer. Most prostate malignancies are adenocarcinomas with luminal differentiation. However, some tumors undergo cellular reprogramming to a more lethal subset termed neuroendocrine prostate cancer (NEPC) with neuronal differentiation. The frequency of NEPC is increasing since the widespread use of potent androgen receptor signaling inhibitors. Currently, there are no effective treatments for NEPC. We previously determined that LSD1 promotes survival of prostate adenocarcinoma tumors. However, the role of LSD1 in NEPC is unknown. Here, we determined that LSD1 is highly upregulated in NEPC versus adenocarcinoma patient tumors. LSD1 suppression with RNAi or allosteric LSD1 inhibitors - but not catalytic inhibitors - reduced NEPC cell survival. RNA-Seq analysis revealed that LSD1 represses pathways linked to luminal differentiation, and TP53 was the top reactivated pathway. We confirmed that LSD1 suppressed the TP53 pathway by reducing TP53 occupancy at target genes while LSD1's catalytic function was dispensable for this effect. Mechanistically, LSD1 inhibition disrupted LSD1-HDAC interactions, increasing histone acetylation at TP53 targets. Finally, LSD1 inhibition suppressed NEPC tumor growth in vivo. These findings suggest that blocking LSD1's noncatalytic function may be a promising treatment strategy for NEPC.
- Published
- 2023
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10. KMT2D links TGF-β signaling to noncanonical activin pathway and regulates pancreatic cancer cell plasticity.
- Author
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Lu S, Kim HS, Cao Y, Bedi K, Zhao L, Narayanan IV, Magnuson B, Gu Y, Yang J, Yi Z, Babaniamansour S, Shameon S, Xu C, Paulsen MT, Qiu P, Jeyarajan S, Ljungman M, Thomas D, Dou Y, Crawford H, di Magliano MP, Ge K, Yang B, and Shi J
- Subjects
- Humans, Animals, Mice, Cell Plasticity, Cell Line, Tumor, Transforming Growth Factor beta metabolism, Activins genetics, MicroRNAs genetics, MicroRNAs metabolism, Pancreatic Neoplasms pathology
- Abstract
Although KMT2D, also known as MLL2, is known to play an essential role in development, differentiation, and tumor suppression, its role in pancreatic cancer development is not well understood. Here, we discovered a novel signaling axis mediated by KMT2D, which links TGF-β to the activin A pathway. We found that TGF-β upregulates a microRNA, miR-147b, which in turn leads to post-transcriptional silencing of KMT2D. Loss of KMT2D induces the expression and secretion of activin A, which activates a noncanonical p38 MAPK-mediated pathway to modulate cancer cell plasticity, promote a mesenchymal phenotype, and enhance tumor invasion and metastasis in mice. We observed a decreased KMT2D expression in human primary and metastatic pancreatic cancer. Furthermore, inhibition or knockdown of activin A reversed the protumoral role of KMT2D loss. These findings support a tumor-suppressive role of KMT2D in pancreatic cancer and identify miR-147b and activin A as novel therapeutic targets., (© 2023 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)
- Published
- 2023
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11. The ENCODE4 long-read RNA-seq collection reveals distinct classes of transcript structure diversity.
- Author
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Reese F, Williams B, Balderrama-Gutierrez G, Wyman D, Çelik MH, Rebboah E, Rezaie N, Trout D, Razavi-Mohseni M, Jiang Y, Borsari B, Morabito S, Liang HY, McGill CJ, Rahmanian S, Sakr J, Jiang S, Zeng W, Carvalho K, Weimer AK, Dionne LA, McShane A, Bedi K, Elhajjajy SI, Upchurch S, Jou J, Youngworth I, Gabdank I, Sud P, Jolanki O, Strattan JS, Kagda MS, Snyder MP, Hitz BC, Moore JE, Weng Z, Bennett D, Reinholdt L, Ljungman M, Beer MA, Gerstein MB, Pachter L, Guigó R, Wold BJ, and Mortazavi A
- Abstract
The majority of mammalian genes encode multiple transcript isoforms that result from differential promoter use, changes in exonic splicing, and alternative 3' end choice. Detecting and quantifying transcript isoforms across tissues, cell types, and species has been extremely challenging because transcripts are much longer than the short reads normally used for RNA-seq. By contrast, long-read RNA-seq (LR-RNA-seq) gives the complete structure of most transcripts. We sequenced 264 LR-RNA-seq PacBio libraries totaling over 1 billion circular consensus reads (CCS) for 81 unique human and mouse samples. We detect at least one full-length transcript from 87.7% of annotated human protein coding genes and a total of 200,000 full-length transcripts, 40% of which have novel exon junction chains. To capture and compute on the three sources of transcript structure diversity, we introduce a gene and transcript annotation framework that uses triplets representing the transcript start site, exon junction chain, and transcript end site of each transcript. Using triplets in a simplex representation demonstrates how promoter selection, splice pattern, and 3' processing are deployed across human tissues, with nearly half of multi-transcript protein coding genes showing a clear bias toward one of the three diversity mechanisms. Evaluated across samples, the predominantly expressed transcript changes for 74% of protein coding genes. In evolution, the human and mouse transcriptomes are globally similar in types of transcript structure diversity, yet among individual orthologous gene pairs, more than half (57.8%) show substantial differences in mechanism of diversification in matching tissues. This initial large-scale survey of human and mouse long-read transcriptomes provides a foundation for further analyses of alternative transcript usage, and is complemented by short-read and microRNA data on the same samples and by epigenome data elsewhere in the ENCODE4 collection.
- Published
- 2023
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12. KDM6A Loss Recruits Tumor-Associated Neutrophils and Promotes Neutrophil Extracellular Trap Formation in Pancreatic Cancer.
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Yang J, Jin L, Kim HS, Tian F, Yi Z, Bedi K, Ljungman M, Pasca di Magliano M, Crawford H, and Shi J
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- Animals, Humans, Mice, Neutrophils metabolism, Tumor Microenvironment, Pancreatic Neoplasms, Carcinoma, Pancreatic Ductal pathology, Extracellular Traps metabolism, Histone Demethylases genetics, Histone Demethylases metabolism, Pancreatic Neoplasms pathology
- Abstract
Lysine (K)-specific demethylase 6A (KDM6A) is a frequently mutated tumor suppressor gene in pancreatic ductal adenocarcinoma (PDAC). However, the impact of KDM6A loss on the PDAC tumor immune microenvironment is not known. This study used a genetically engineered, pancreas-specific Kdm6a knockout (KO) PDAC mouse model and human PDAC tissue samples to demonstrate that KDM6A loss correlates with increased tumor-associated neutrophils and neutrophil extracellular traps (NET) formation, which are known to contribute to PDAC progression. Genome-wide bromouridine sequencing analysis to evaluate nascent RNA synthesis showed that the expression of many chemotactic cytokines, especially CXC motif chemokine ligand 1 (CXCL1), was upregulated in KDM6A KO PDAC cells. KDM6A-deficient PDAC cells secreted higher levels of CXCL1 protein, which in turn recruited neutrophils. Furthermore, in a syngeneic orthotopic mouse model, treatment with a CXCL1 neutralizing antibody blocked the chemotactic and NET-promoting properties of KDM6A-deficient PDAC cells and suppressed tumor growth, confirming CXCL1 as a key mediator of chemotaxis and PDAC growth driven by KDM6A loss. These findings shed light on how KDM6A regulates the tumor immune microenvironment and PDAC progression and suggests that the CXCL1-CXCR2 axis may be a candidate target in PDAC with KDM6A loss., Significance: KDM6A loss in pancreatic cancer cells alters the immune microenvironment by increasing CXCL1 secretion and neutrophil recruitment, providing a rationale for targeting the CXCL1-CXCR2 signaling axis in tumors with low KDM6A., (©2022 American Association for Cancer Research.)
- Published
- 2022
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13. Glutamine uptake and catabolism is required for myofibroblast formation and persistence.
- Author
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Gibb AA, Huynh AT, Gaspar RB, Ploesch TL, Lombardi AA, Lorkiewicz PK, Lazaropoulos MP, Bedi K, Arany Z, Margulies KB, Hill BG, and Elrod JW
- Subjects
- Humans, Mice, Animals, Glutamine metabolism, Fibroblasts metabolism, Collagen metabolism, Cells, Cultured, Myofibroblasts metabolism
- Abstract
Background: Fibrosis and extracellular matrix remodeling are mediated by resident cardiac fibroblasts (CFs). In response to injury, fibroblasts activate, differentiating into specialized synthetic and contractile myofibroblasts producing copious extracellular matrix proteins (e.g., collagens). Myofibroblast persistence in chronic diseases, such as HF, leads to progressive cardiac dysfunction and maladaptive remodeling. We recently reported that an increase in αKG (alpha-ketoglutarate) bioavailability, which contributes to enhanced αKG-dependent lysine demethylase activity and chromatin remodeling, is required for myofibroblast formation. Therefore, we aimed to determine the substrates and metabolic pathways contributing to αKG biosynthesis and their requirement for myofibroblast formation., Methods: Stable isotope metabolomics identified glutaminolysis as a key metabolic pathway required for αKG biosynthesis and myofibroblast formation, therefore we tested the effects of pharmacologic inhibition (CB-839) or genetic deletion of glutaminase (Gls1
-/- ) on myofibroblast formation in both murine and human cardiac fibroblasts. We employed immunofluorescence staining, functional gel contraction, western blotting, and bioenergetic assays to determine the myofibroblast phenotype., Results: Carbon tracing indicated enhanced glutaminolysis mediating increased αKG abundance. Pharmacological and genetic inhibition of glutaminolysis prevented myofibroblast formation indicated by a reduction in αSMA+ cells, collagen gel contraction, collagen abundance, and the bioenergetic response. Inhibition of glutaminolysis also prevented TGFβ-mediated histone demethylation and supplementation with cell-permeable αKG rescued the myofibroblast phenotype. Importantly, inhibition of glutaminolysis was sufficient to prevent myofibroblast formation in CFs isolated from the human failing heart., Conclusions: These results define glutaminolysis as necessary for myofibroblast formation and persistence, providing substantial rationale to evaluate several new therapeutic targets to treat cardiac fibrosis., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022 Elsevier Ltd. All rights reserved.)- Published
- 2022
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14. CDK12 regulates co-transcriptional splicing and RNA turnover in human cells.
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Magnuson B, Bedi K, Narayanan IV, Bartkowiak B, Blinkiewicz H, Paulsen MT, Greenleaf A, and Ljungman M
- Abstract
The cyclin-dependent kinase CDK12 has garnered interest as a cancer therapeutic target as DNA damage response genes are particularly suppressed by loss of CDK12 activity. In this study, we assessed the acute effects of CDK12 inhibition on transcription and RNA processing using nascent RNA Bru-seq and BruChase-seq. Acute transcriptional changes were overall small after CDK12 inhibition but over 600 genes showed intragenic premature termination, including DNA repair and cell cycle genes. Furthermore, many genes showed reduced transcriptional readthrough past the end of genes in the absence of CDK12 activity. RNA turnover was dramatically affected by CDK12 inhibition and importantly, caused increased degradation of many transcripts from DNA damage response genes. We also show that co-transcriptional splicing was suppressed by CDK12 inhibition. Taken together, these studies reveal the roles of CDK12 in regulating transcription elongation, transcription termination, co-transcriptional splicing, and RNA turnover., Competing Interests: The authors declare no competing interest., (© 2022 The Author(s).)
- Published
- 2022
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15. Myotubularin-related phosphatase 5 is a critical determinant of autophagy in neurons.
- Author
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Chua JP, Bedi K, Paulsen MT, Ljungman M, Tank EMH, Kim ES, McBride JP, Colón-Mercado JM, Ward ME, Weisman LS, and Barmada SJ
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- Autophagy genetics, Neurons physiology, Autophagosomes metabolism, Protein Tyrosine Phosphatases, Non-Receptor genetics, Protein Tyrosine Phosphatases, Non-Receptor metabolism
- Abstract
Autophagy is a conserved, multi-step process of capturing proteolytic cargo in autophagosomes for lysosome degradation. The capacity to remove toxic proteins that accumulate in neurodegenerative disorders attests to the disease-modifying potential of the autophagy pathway. However, neurons respond only marginally to conventional methods for inducing autophagy, limiting efforts to develop therapeutic autophagy modulators for neurodegenerative diseases. The determinants underlying poor autophagy induction in neurons and the degree to which neurons and other cell types are differentially sensitive to autophagy stimuli are incompletely defined. Accordingly, we sampled nascent transcript synthesis and stabilities in fibroblasts, induced pluripotent stem cells (iPSCs), and iPSC-derived neurons (iNeurons), thereby uncovering a neuron-specific stability of transcripts encoding myotubularin-related phosphatase 5 (MTMR5). MTMR5 is an autophagy suppressor that acts with its binding partner, MTMR2, to dephosphorylate phosphoinositides critical for autophagy initiation and autophagosome maturation. We found that MTMR5 is necessary and sufficient to suppress autophagy in iNeurons and undifferentiated iPSCs. Using optical pulse labeling to visualize the turnover of endogenously encoded proteins in live cells, we observed that knockdown of MTMR5 or MTMR2, but not the unrelated phosphatase MTMR9, significantly enhances neuronal degradation of TDP-43, an autophagy substrate implicated in several neurodegenerative diseases. Our findings thus establish a regulatory mechanism of autophagy intrinsic to neurons and targetable for clearing disease-related proteins in a cell-type-specific manner. In so doing, our results not only unravel novel aspects of neuronal biology and proteostasis but also elucidate a strategy for modulating neuronal autophagy that could be of high therapeutic potential for multiple neurodegenerative diseases., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 Elsevier Inc. All rights reserved.)
- Published
- 2022
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16. Glutaminolysis is Essential for Myofibroblast Persistence and In Vivo Targeting Reverses Fibrosis and Cardiac Dysfunction in Heart Failure.
- Author
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Gibb AA, Murray EK, Huynh AT, Gaspar RB, Ploesch TL, Bedi K, Lombardi AA, Lorkiewicz PK, Roy R, Arany Z, Kelly DP, Margulies KB, Hill BG, and Elrod JW
- Subjects
- Cells, Cultured, Fibrosis, Humans, Myocardium, Myofibroblasts pathology, Heart Diseases pathology, Heart Failure drug therapy, Heart Failure pathology
- Published
- 2022
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17. Transcriptional, Post-Transcriptional, and Post-Translational Mechanisms Rewrite the Tubulin Code During Cardiac Hypertrophy and Failure.
- Author
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Phyo SA, Uchida K, Chen CY, Caporizzo MA, Bedi K, Griffin J, Margulies K, and Prosser BL
- Abstract
A proliferated and post-translationally modified microtubule network underlies cellular growth in cardiac hypertrophy and contributes to contractile dysfunction in heart failure. Yet how the heart achieves this modified network is poorly understood. Determining how the "tubulin code"-the permutations of tubulin isoforms and post-translational modifications-is rewritten upon cardiac stress may provide new targets to modulate cardiac remodeling. Further, while tubulin can autoregulate its own expression, it is unknown if autoregulation is operant in the heart or tuned in response to stress. Here we use heart failure patient samples and murine models of cardiac remodeling to interrogate transcriptional, autoregulatory, and post-translational mechanisms that contribute to microtubule network remodeling at different stages of heart disease. We find that autoregulation is operant across tubulin isoforms in the heart and leads to an apparent disconnect in tubulin mRNA and protein levels in heart failure. We also find that within 4 h of a hypertrophic stimulus and prior to cardiac growth, microtubule detyrosination is rapidly induced to help stabilize the network. This occurs concomitant with rapid transcriptional and autoregulatory activation of specific tubulin isoforms and microtubule motors. Upon continued hypertrophic stimulation, there is an increase in post-translationally modified microtubule tracks and anterograde motors to support cardiac growth, while total tubulin content increases through progressive transcriptional and autoregulatory induction of tubulin isoforms. Our work provides a new model for how the tubulin code is rapidly rewritten to establish a proliferated, stable microtubule network that drives cardiac remodeling, and provides the first evidence of tunable tubulin autoregulation during pathological progression., 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., (Copyright © 2022 Phyo, Uchida, Chen, Caporizzo, Bedi, Griffin, Margulies and Prosser.)
- Published
- 2022
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18. KDM6A Regulates Cell Plasticity and Pancreatic Cancer Progression by Noncanonical Activin Pathway.
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Yi Z, Wei S, Jin L, Jeyarajan S, Yang J, Gu Y, Kim HS, Schechter S, Lu S, Paulsen MT, Bedi K, Narayanan IV, Ljungman M, Crawford HC, Pasca di Magliano M, Ge K, Dou Y, and Shi J
- Subjects
- Activins metabolism, Animals, Histone Demethylases genetics, Histone Demethylases metabolism, Humans, Mice, Pancreas pathology, Cell Plasticity, Pancreatic Neoplasms pathology
- Abstract
Background & Aims: Inactivating mutations of KDM6A, a histone demethylase, were frequently found in pancreatic ductal adenocarcinoma (PDAC). We investigated the role of KDM6A (lysine demethylase 6A) in PDAC development., Methods: We performed a pancreatic tissue microarray analysis of KDM6A protein levels. We used human PDAC cell lines for KDM6A knockout and knockdown experiments. We performed bromouridine sequencing analysis to elucidate the effects of KDM6A loss on global transcription. We performed studies with Ptf1a
Cre ; LSL-KrasG12D ; Trp53R172H/+ ; Kdm6afl/fl or fl/Y , Ptf1aCre ; Kdm6afl/fl or fl/Y , and orthotopic xenograft mice to investigate the impacts of Kdm6a deficiency on pancreatic tumorigenesis and pancreatitis., Results: Loss of KDM6A was associated with metastasis in PDAC patients. Bromouridine sequencing analysis showed up-regulation of the epithelial-mesenchymal transition pathway in PDAC cells deficient in KDM6A. Loss of KDM6A promoted mesenchymal morphology, migration, and invasion in PDAC cells in vitro. Mechanistically, activin A and subsequent p38 activation likely mediated the role of KDM6A loss. Inhibiting either activin A or p38 reversed the effect. Pancreas-specific Kdm6a-knockout mice pancreata showed accelerated PDAC progression, developed a more aggressive undifferentiated type of PDAC, and increased metastases in the background of Kras and p53 mutations. Kdm6a-deficient pancreata in a pancreatitis model had a delayed recovery with increased PDAC precursor lesions compared with wild-type pancreata., Conclusions: Loss of KDM6A accelerates PDAC progression and metastasis, most likely by a noncanonical p38-dependent activin A pathway. KDM6A also promotes pancreatic tissue recovery from pancreatitis. Activin A might be used as a therapeutic target for KDM6A-deficient PDACs., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2022
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19. Analysis of the initial lot of the CDC 2019-Novel Coronavirus (2019-nCoV) real-time RT-PCR diagnostic panel.
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Lee JS, Goldstein JM, Moon JL, Herzegh O, Bagarozzi DA Jr, Oberste MS, Hughes H, Bedi K, Gerard D, Cameron B, Benton C, Chida A, Ahmad A, Petway DJ Jr, Tang X, Sulaiman N, Teklu D, Batra D, Howard D, Sheth M, Kuhnert W, Bialek SR, Hutson CL, Pohl J, and Carroll DS
- Subjects
- Humans, United States, False Positive Reactions, COVID-19 Nucleic Acid Testing methods, Reverse Transcriptase Polymerase Chain Reaction methods, Sensitivity and Specificity, RNA, Viral genetics, RNA, Viral analysis, SARS-CoV-2 genetics, SARS-CoV-2 isolation & purification, Centers for Disease Control and Prevention, U.S., COVID-19 diagnosis, COVID-19 virology, Real-Time Polymerase Chain Reaction methods
- Abstract
At the start of the COVID-19 pandemic, the Centers for Disease Control and Prevention (CDC) designed, manufactured, and distributed the CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel for SARS-CoV-2 detection. The diagnostic panel targeted three viral nucleocapsid gene loci (N1, N2, and N3 primers and probes) to maximize sensitivity and to provide redundancy for virus detection if mutations occurred. After the first distribution of the diagnostic panel, state public health laboratories reported fluorescent signal in the absence of viral template (false-positive reactivity) for the N3 component and to a lesser extent for N1. This report describes the findings of an internal investigation conducted by the CDC to identify the cause(s) of the N1 and N3 false-positive reactivity. For N1, results demonstrate that contamination with a synthetic template, that occurred while the "bulk" manufactured materials were located in a research lab for quality assessment, was the cause of false reactivity in the first lot. Base pairing between the 3' end of the N3 probe and the 3' end of the N3 reverse primer led to amplification of duplex and larger molecules resulting in false reactivity in the N3 assay component. We conclude that flaws in both assay design and handling of the "bulk" material, caused the problems with the first lot of the 2019-nCoV Real-Time RT-PCR Diagnostic Panel. In addition, within this study, we found that the age of the examined diagnostic panel reagents increases the frequency of false positive results for N3. We discuss these findings in the context of improvements to quality control, quality assurance, and assay validation practices that have since been improved at the CDC., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
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20. S-Nitrosylation of Histone Deacetylase 2 by Neuronal Nitric Oxide Synthase as a Mechanism of Diastolic Dysfunction.
- Author
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Yoon S, Kim M, Lee H, Kang G, Bedi K, Margulies KB, Jain R, Nam KI, Kook H, and Eom GH
- Subjects
- Animals, Disease Models, Animal, Humans, Mice, Heart Murmurs physiopathology, Histone Deacetylase 2 metabolism, Nitric Oxide metabolism, Nitric Oxide Synthase Type I metabolism
- Abstract
Background: Although the clinical importance of heart failure with preserved ejection fraction has been extensively explored, most therapeutic regimens, including nitric oxide (NO) donors, lack therapeutic benefit. Although the clinical characteristics of heart failure with preserved ejection fraction are somewhat heterogeneous, diastolic dysfunction (DD) is one of the most important features. Here we report that neuronal NO synthase (nNOS) induces DD by S-nitrosylation of HDAC2 (histone deacetylase 2)., Methods: Two animal models of DD-SAUNA (SAlty drinking water/Unilateral Nephrectomy/Aldosterone) and mild transverse aortic constriction mice-as well as human heart samples from patients with left ventricular hypertrophy were used. Genetically modified mice that were either nNOS-ablated or HDAC2 S-nitrosylation-resistant were also challenged. N(ω)-propyl-L-arginine, an nNOS selective inhibitor, and dimethyl fumarate, an NRF2 (nuclear factor erythroid 2-related factor 2) inducer, were used. Molecular events were further checked in human left ventricle specimens., Results: SAUNA or mild transverse aortic constriction stress impaired diastolic function and exercise tolerance without overt systolic failure. Among the posttranslational modifications tested, S-nitrosylation was most dramatically increased in both models. Utilizing heart samples from both mice and humans, we observed increases in nNOS expression and NO production. N(ω)-propyl-L-arginine alleviated the development of DD in vivo. Similarly, nNOS knockout mice were resistant to SAUNA stress. nNOS-induced S-nitrosylation of HDAC2 was relayed by transnitrosylation of GAPDH. HDAC2 S-nitrosylation was confirmed in both DD mouse and human left ventricular hypertrophy. S-nitrosylation of HDAC2 took place at C262 and C274. When DD was induced, HDAC2 S-nitrosylation was detected in wild-type mouse, but not in HDAC2 knock-in mouse heart that expressed HDAC2 C262A/C274A. In addition, HDAC2 C262A/C274A mice maintained normal diastolic function under DD stimuli. Gene delivery with adenovirus-associated virus 9 (AAV9)-NRF2, a putative denitrosylase of HDAC2, or pharmacological intervention by dimethyl fumarate successfully induced HDAC2 denitrosylation and mitigated DD in vivo., Conclusions: Our observations are the first to demonstrate a new mechanism underlying DD pathophysiology. Our results provide theoretical and experimental evidence to explain the ineffectiveness of conventional NO enhancement trials for improving DD with heart failure symptoms. More important, our results suggest that reduction of NO or denitrosylation of HDAC2 may provide a new therapeutic platform for the treatment of refractory heart failure with preserved ejection fraction.
- Published
- 2021
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21. Co-transcriptional splicing efficiencies differ within genes and between cell types.
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Bedi K, Magnuson BR, Narayanan I, Paulsen M, Wilson TE, and Ljungman M
- Abstract
Pre-mRNA splicing is carried out by the spliceosome and involves splice site recognition, removal of introns, and ligation of exons. Components of the spliceosome have been shown to interact with the elongating RNA polymerase II (RNAPII) which is thought to allow splicing to occur concurrently with transcription. However, little is known about the regulation and efficiency of co-transcriptional splicing in human cells. In this study, we used Bru-seq and BruChase-seq to determine the co-transcriptional splicing efficiencies of 17,000 introns expressed across 6 human cell lines. We found that less than half of all introns across these 6 cell lines were co-transcriptionally spliced. Splicing efficiencies for individual introns showed variations across cell lines, suggesting that splicing may be regulated in a cell-type specific manner. Moreover, the splicing efficiency of introns varied within genes. The efficiency of co-transcriptional splicing did not correlate with gene length, intron position, splice site strengths, or the intron/neighboring exons GC content. However, we identified binding signals from multiple RNA binding proteins (RBPs) that correlated with splicing efficiency, including core spliceosomal machinery components-such as SF3B4, U2AF1 and U2AF2 showing higher binding signals in poorly spliced introns. In addition, multiple RBPs, such as BUD13, PUM1 and SND1, showed preferential binding in exons that flank introns with high splicing efficiencies. The nascent RNA splicing patterns presented here across multiple cell types add to our understanding of the complexity in RNA splicing, wherein RNA-binding proteins may play important roles in determining splicing outcomes in a cell type- and intron-specific manner., (Published by Cold Spring Harbor Laboratory Press for the RNA Society.)
- Published
- 2021
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22. Pathogenic LMNA variants disrupt cardiac lamina-chromatin interactions and de-repress alternative fate genes.
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Shah PP, Lv W, Rhoades JH, Poleshko A, Abbey D, Caporizzo MA, Linares-Saldana R, Heffler JG, Sayed N, Thomas D, Wang Q, Stanton LJ, Bedi K, Morley MP, Cappola TP, Owens AT, Margulies KB, Frank DB, Wu JC, Rader DJ, Yang W, Prosser BL, Musunuru K, and Jain R
- Subjects
- Chromatin genetics, Humans, Lamin Type A genetics, Mutation genetics, Myocytes, Cardiac, Cardiomyopathy, Dilated genetics, Induced Pluripotent Stem Cells
- Abstract
Pathogenic mutations in LAMIN A/C (LMNA) cause abnormal nuclear structure and laminopathies. These diseases have myriad tissue-specific phenotypes, including dilated cardiomyopathy (DCM), but how LMNA mutations result in tissue-restricted disease phenotypes remains unclear. We introduced LMNA mutations from individuals with DCM into human induced pluripotent stem cells (hiPSCs) and found that hiPSC-derived cardiomyocytes, in contrast to hepatocytes or adipocytes, exhibit aberrant nuclear morphology and specific disruptions in peripheral chromatin. Disrupted regions were enriched for transcriptionally active genes and regions with lower LAMIN B1 contact frequency. The lamina-chromatin interactions disrupted in mutant cardiomyocytes were enriched for genes associated with non-myocyte lineages and correlated with higher expression of those genes. Myocardium from individuals with LMNA variants similarly showed aberrant expression of non-myocyte pathways. We propose that the lamina network safeguards cellular identity and that pathogenic LMNA variants disrupt peripheral chromatin with specific epigenetic and molecular characteristics, causing misexpression of genes normally expressed in other cell types., Competing Interests: Declaration of interests K.M. is an advisor to and holds equity in Variant Bio and Verve Therapeutics., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2021
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23. Transcriptomic Analysis of Diffuse Intrinsic Pontine Glioma (DIPG) Identifies a Targetable ALDH-Positive Subset of Highly Tumorigenic Cancer Stem-like Cells.
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Surowiec RK, Ferris SF, Apfelbaum A, Espinoza C, Mehta RK, Monchamp K, Sirihorachai VR, Bedi K, Ljungman M, and Galban S
- Subjects
- Animals, Cell Line, Tumor, Diffuse Intrinsic Pontine Glioma pathology, Humans, Male, Mice, Xenograft Model Antitumor Assays, Aldehyde Dehydrogenase metabolism, Diffuse Intrinsic Pontine Glioma genetics, Neoplastic Stem Cells metabolism, Transcriptome genetics
- Abstract
Understanding the cancer stem cell (CSC) landscape in diffuse intrinsic pontine glioma (DIPG) is desperately needed to address treatment resistance and identify novel therapeutic approaches. Patient-derived DIPG cells demonstrated heterogeneous expression of aldehyde dehydrogenase (ALDH) and CD133 by flow cytometry. Transcriptome-level characterization identified elevated mRNA levels of MYC, E2F , DNA damage repair (DDR) genes, glycolytic metabolism, and mTOR signaling in ALDH
+ compared with ALDH- , supporting a stem-like phenotype and indicating a druggable target. ALDH+ cells demonstrated increased proliferation, neurosphere formation, and initiated tumors that resulted in decreased survival when orthotopically implanted. Pharmacologic MAPK/PI3K/mTOR targeting downregulated MYC, E2F , and DDR mRNAs and reduced glycolytic metabolism. In vivo PI3K/mTOR targeting inhibited tumor growth in both flank and an ALDH+ orthotopic tumor model likely by reducing cancer stemness. In summary, we describe existence of ALDH+ DIPGs with proliferative properties due to increased metabolism, which may be regulated by the microenvironment and likely contributing to drug resistance and tumor recurrence. IMPLICATIONS: Characterization of ALDH+ DIPGs coupled with targeting MAPK/PI3K/mTOR signaling provides an impetus for molecularly targeted therapy aimed at addressing the CSC phenotype in DIPG., (©2020 American Association for Cancer Research.)- Published
- 2021
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24. Myocardial Gene Expression Signatures in Human Heart Failure With Preserved Ejection Fraction.
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Hahn VS, Knutsdottir H, Luo X, Bedi K, Margulies KB, Haldar SM, Stolina M, Yin J, Khakoo AY, Vaishnav J, Bader JS, Kass DA, and Sharma K
- Subjects
- Aged, Cardiac Catheterization methods, Female, Heart Failure pathology, Humans, Male, Middle Aged, Myocardium pathology, Prospective Studies, Heart Failure genetics, Heart Failure metabolism, Myocardium metabolism, Stroke Volume physiology, Transcriptome physiology
- Abstract
Background: Heart failure (HF) with preserved ejection fraction (HFpEF) constitutes half of all HF but lacks effective therapy. Understanding of its myocardial biology remains limited because of a paucity of heart tissue molecular analysis., Methods: We performed RNA sequencing on right ventricular septal endomyocardial biopsies prospectively obtained from patients meeting consensus criteria for HFpEF (n=41) contrasted with right ventricular septal tissue from patients with HF with reduced ejection fraction (HFrEF, n=30) and donor controls (n=24). Principal component analysis and hierarchical clustering tested for transcriptomic distinctiveness between groups, effect of comorbidities, and differential gene expression with pathway enrichment contrasted HF groups and donor controls. Within HFpEF, non-negative matrix factorization and weighted gene coexpression analysis identified molecular subgroups, and the resulting clusters were correlated with hemodynamic and clinical data., Results: Patients with HFpEF were more often women (59%), African American (68%), obese (median body mass index 41), and hypertensive (98%), with clinical HF characterized by 65% New York Heart Association Class III or IV, nearly all on a loop diuretic, and 70% with a HF hospitalization in the previous year. Principal component analysis separated HFpEF from HFrEF and donor controls with minimal overlap, and this persisted after adjusting for primary comorbidities: body mass index, sex, age, diabetes, and renal function. Hierarchical clustering confirmed group separation. Nearly half the significantly altered genes in HFpEF versus donor controls (1882 up, 2593 down) changed in the same direction in HFrEF; however, 5745 genes were uniquely altered between HF groups. Compared with controls, uniquely upregulated genes in HFpEF were enriched in mitochondrial adenosine triphosphate synthesis/electron transport, pathways downregulated in HFrEF. HFpEF-specific downregulated genes engaged endoplasmic reticulum stress, autophagy, and angiogenesis. Body mass index differences largely accounted for HFpEF upregulated genes, whereas neither this nor broader comorbidity adjustment altered pathways enriched in downregulated genes. Non-negative matrix factorization identified 3 HFpEF transcriptomic subgroups with distinctive pathways and clinical correlates, including a group closest to HFrEF with higher mortality, and a mostly female group with smaller hearts and proinflammatory signaling. These groupings remained after sex adjustment. Weighted gene coexpression analysis yielded analogous gene clusters and clinical groupings., Conclusions: HFpEF exhibits distinctive broad transcriptomic signatures and molecular subgroupings with particular clinical features and outcomes. The data reveal new signaling targets to consider for precision therapeutics.
- Published
- 2021
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25. Comparison of Zika virus inactivation methods for reagent production and disinfection methods.
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Chida AS, Goldstein JM, Lee J, Tang X, Bedi K, Herzegh O, Moon JL, Petway D, Bagarozzi DA Jr, and Hughes LJ
- Subjects
- Disinfection, Humans, Indicators and Reagents, Virus Inactivation, Zika Virus, Zika Virus Infection diagnosis
- Abstract
Zika virus (ZIKV) infection remains a public health concern necessitating demand for long-term virus production for diagnostic assays and R&D activities. Inactivated virus constitutes an important component of the Trioplex rRT-PCR assay and serological IgM assay (MAC-ELISA). The aim of our study is to establish standard methods of ZIKV inactivation while maintaining antigenicity and RNA integrity. We tested viral supernatants by four different inactivation methods: 1. Heat inactivation at 56 °C and 60 °C; 2. Gamma-Irradiation; 3. Chemical inactivation by Beta-propiolactone (BPL) and 4. Fast-acting commercial disinfecting agents. Effectivity was measured by cytopathic effect (CPE) and plaque assay. RNA stability and antigenicity were measured by RT-PCR and MAC-ELISA, respectively. Results: Heat inactivation: Low titer samples, incubated at 56 °C for 2 h, showed neither CPE or plaques compared to high titer supernatants that required 2.5 h. Inactivation occurred at 60 °C for 60 min with all virus titers. Gamma irradiation: Samples irradiated at ≥3 Mrad for low virus concentrations and ≥5Mrad for high virus titer completely inactivated virus. Chemical Inactivation: Neither CPE nor plaques were observed with ≥0.045 % BPL inactivation of ZIKV. Disinfectant: Treatment of viral supernatants with Micro-Chem Plus™, inactivated virus in 2 min, whereas, Ethanol (70 %) and STERIS Coverage® Spray TB inactivated the virus in 5 min., (Published by Elsevier B.V.)
- Published
- 2021
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26. Epigenetic Analyses of Human Left Atrial Tissue Identifies Gene Networks Underlying Atrial Fibrillation.
- Author
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Hall AW, Chaffin M, Roselli C, Lin H, Lubitz SA, Bianchi V, Geeven G, Bedi K, Margulies KB, de Laat W, Tucker NR, and Ellinor PT
- Subjects
- Amino Acid Motifs genetics, Base Sequence, Chromatin metabolism, DNA Methylation genetics, Enhancer Elements, Genetic genetics, Female, Humans, Male, Middle Aged, Models, Genetic, Tissue Donors, Transcription, Genetic, Atrial Fibrillation genetics, Epigenesis, Genetic, Gene Regulatory Networks, Heart Atria pathology
- Abstract
Background: Atrial fibrillation (AF) often arises from structural abnormalities in the left atria (LA). Annotation of the noncoding genome in human LA is limited, as are effects on gene expression and chromatin architecture. Many AF-associated genetic variants reside in noncoding regions; this knowledge gap impairs efforts to understand the molecular mechanisms of AF and cardiac conduction phenotypes., Methods: We generated a model of the LA noncoding genome by profiling 7 histone post-translational modifications (active: H3K4me3, H3K4me2, H3K4me1, H3K27ac, H3K36me3; repressive: H3K27me3, H3K9me3), CTCF binding, and gene expression in samples from 5 individuals without structural heart disease or AF. We used MACS2 to identify peak regions ( P <0.01), applied a Markov model to classify regulatory elements, and annotated this model with matched gene expression data. We intersected chromatin states with expression quantitative trait locus, DNA methylation, and HiC chromatin interaction data from LA and left ventricle. Finally, we integrated genome-wide association data for AF and electrocardiographic traits to link disease-related variants to genes., Results: Our model identified 21 epigenetic states, encompassing regulatory motifs, such as promoters, enhancers, and repressed regions. Genes were regulated by proximal chromatin states; repressive states were associated with a significant reduction in gene expression ( P <2×10
-16 ). Chromatin states were differentially methylated, promoters were less methylated than repressed regions ( P <2×10-16 ). We identified over 15 000 LA-specific enhancers, defined by homeobox family motifs, and annotated several cardiovascular disease susceptibility loci. Intersecting AF and PR genome-wide association studies loci with long-range chromatin conformation data identified a gene interaction network dominated by NKX2-5 , TBX3 , ZFHX3 , and SYNPO2L ., Conclusions: Profiling the noncoding genome provides new insights into the gene expression and chromatin regulation in human LA tissue. These findings enabled identification of a gene network underlying AF; our experimental and analytic approach can be extended to identify molecular mechanisms for other cardiac diseases and traits.- Published
- 2020
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27. Multivalent Proteins Rapidly and Reversibly Phase-Separate upon Osmotic Cell Volume Change.
- Author
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Jalihal AP, Pitchiaya S, Xiao L, Bawa P, Jiang X, Bedi K, Parolia A, Cieslik M, Ljungman M, Chinnaiyan AM, and Walter NG
- Subjects
- Animals, Cell Size, Cell Survival genetics, Humans, Osmotic Pressure physiology, Proteome genetics, Endoribonucleases genetics, RNA Precursors genetics, Stress, Physiological genetics, Trans-Activators genetics, Transcription Termination, Genetic
- Abstract
Processing bodies (PBs) and stress granules (SGs) are prominent examples of subcellular, membraneless compartments that are observed under physiological and stress conditions, respectively. We observe that the trimeric PB protein DCP1A rapidly (within ∼10 s) phase-separates in mammalian cells during hyperosmotic stress and dissolves upon isosmotic rescue (over ∼100 s) with minimal effect on cell viability even after multiple cycles of osmotic perturbation. Strikingly, this rapid intracellular hyperosmotic phase separation (HOPS) correlates with the degree of cell volume compression, distinct from SG assembly, and is exhibited broadly by homo-multimeric (valency ≥ 2) proteins across several cell types. Notably, HOPS sequesters pre-mRNA cleavage factor components from actively transcribing genomic loci, providing a mechanism for hyperosmolarity-induced global impairment of transcription termination. Our data suggest that the multimeric proteome rapidly responds to changes in hydration and molecular crowding, revealing an unexpected mode of globally programmed phase separation and sequestration., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
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28. Depletion of Vasohibin 1 Speeds Contraction and Relaxation in Failing Human Cardiomyocytes.
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Chen CY, Salomon AK, Caporizzo MA, Curry S, Kelly NA, Bedi K, Bogush AI, Krämer E, Schlossarek S, Janiak P, Moutin MJ, Carrier L, Margulies KB, and Prosser BL
- Subjects
- Angiogenic Proteins genetics, Angiogenic Proteins metabolism, Animals, Carrier Proteins metabolism, Cell Cycle Proteins genetics, Cells, Cultured, HEK293 Cells, Heart Failure physiopathology, Humans, Mutation, Myocytes, Cardiac physiology, Rats, Rats, Sprague-Dawley, Cell Cycle Proteins metabolism, Heart Failure metabolism, Myocardial Contraction, Myocytes, Cardiac metabolism
- Abstract
Rationale: Impaired myocardial relaxation is an intractable feature of several heart failure (HF) causes. In human HF, detyrosinated microtubules stiffen cardiomyocytes and impair relaxation. Yet the identity of detyrosinating enzymes have remained ambiguous, hindering mechanistic study and therapeutic development., Objective: We aimed to determine if the recently identified complex of VASH1/2 (vasohibin 1/2) and SVBP (small vasohibin binding protein) is an active detyrosinase in cardiomyocytes and if genetic inhibition of VASH-SVBP is sufficient to lower stiffness and improve contractility in HF., Methods and Results: Transcriptional profiling revealed that VASH1 transcript is >10-fold more abundant than VASH2 in human hearts. Using short hairpin RNAs (shRNAs) against VASH1 , VASH2 , and SVBP , we showed that both VASH1- and VASH2-SVBP complexes function as tubulin carboxypeptidases in cardiomyocytes, with a predominant role for VASH1. We also generated a catalytically dead version of the tyrosinating enzyme TTL (TTL-E331Q) to separate the microtubule depolymerizing effects of TTL from its enzymatic activity. Assays of microtubule stability revealed that both TTL and TTL-E331Q depolymerize microtubules, while VASH1 and SVBP depletion reduce detyrosination independent of depolymerization. We next probed effects on human cardiomyocyte contractility. Contractile kinetics were slowed in HF, with dramatically slowed relaxation in cardiomyocytes from patients with HF with preserved ejection fraction. Knockdown of VASH1 conferred subtle kinetic improvements in nonfailing cardiomyocytes, while markedly improving kinetics in failing cardiomyocytes. Further, TTL, but not TTL-E331Q, robustly sped relaxation. Simultaneous measurements of calcium transients and contractility demonstrated that VASH1 depletion speeds kinetics independent from alterations to calcium cycling. Finally, atomic force microscopy confirmed that VASH1 depletion reduces the stiffness of failing human cardiomyocytes., Conclusions: VASH-SVBP complexes are active tubulin carboxypeptidases in cardiomyocytes. Inhibition of VASH1 or activation of TTL is sufficient to lower stiffness and speed relaxation in cardiomyocytes from patients with HF, supporting further pursuit of detyrosination as a therapeutic target for diastolic dysfunction.
- Published
- 2020
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29. Integration of Community Health and Prevention Topics in an Osteopathic Medical School Curriculum.
- Author
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Goldgraben S, Johnston E, Bedi K, Chun L, and Kadavakollu S
- Abstract
This article was migrated. The article was marked as recommended. Preventable chronic disease is a leading cause of death and disability in the United States and around the world. Training in wellness and disease prevention is provided to varying degrees in medical education leading to low levels of counseling on prevention-related topics in clinical care. Colleges of osteopathic medicine are in a unique position to lead the way in training future physicians in community health and prevention topics. Integrating community health and wellness throughout the curriculum allows osteopathic medical students to learn the scientific basis for prevention recommendations and learn to apply them to future patient care. We are incorporating these topics across the first two years of medical school in a new college of osteopathic medicine in the USA. This will address local disparities and train physicians prepared to care for patients at the individual and population health levels., (Copyright: © 2020 Goldgraben S et al.)
- Published
- 2020
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30. Microtubules Increase Diastolic Stiffness in Failing Human Cardiomyocytes and Myocardium.
- Author
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Caporizzo MA, Chen CY, Bedi K, Margulies KB, and Prosser BL
- Subjects
- Adult, Aged, Colchicine pharmacology, Diastole, Elasticity, Female, Humans, Male, Microtubules drug effects, Microtubules metabolism, Microtubules ultrastructure, Middle Aged, Myocardial Contraction, Myocytes, Cardiac drug effects, Protein Processing, Post-Translational, Sesquiterpenes pharmacology, Stress, Mechanical, Stroke Volume, Tyrosine metabolism, Ventricular Dysfunction, Left pathology, Viscosity, Heart Failure pathology, Microtubules physiology, Myocardium ultrastructure, Myocytes, Cardiac ultrastructure
- Abstract
Background: Diastolic dysfunction is a prevalent and therapeutically intractable feature of heart failure (HF). Increasing ventricular compliance can improve diastolic performance, but the viscoelastic forces that resist diastolic filling and become elevated in human HF are poorly defined. Having recently identified posttranslationally detyrosinated microtubules as a source of viscoelasticity in cardiomyocytes, we sought to test whether microtubules contribute meaningful viscoelastic resistance to diastolic stretch in human myocardium., Methods: Experiments were conducted in isolated human cardiomyocytes and trabeculae. First, slow and rapid (diastolic) stretch was applied to intact cardiomyocytes from nonfailing and HF hearts and viscoelasticity was characterized after interventions targeting microtubules. Next, intact left ventricular trabeculae from HF patient hearts were incubated with colchicine or vehicle and subject to pre- and posttreatment mechanical testing, which consisted of a staircase protocol and rapid stretches from slack length to increasing strains., Results: Viscoelasticity was increased during diastolic stretch of HF cardiomyocytes compared with nonfailing counterparts. Reducing either microtubule density or detyrosination reduced myocyte stiffness, particularly at diastolic strain rates, indicating reduced viscous forces. In myocardial tissue, we found microtubule depolymerization reduced myocardial viscoelasticity, with an effect that decreased with increasing strain. Colchicine reduced viscoelasticity at strains below, but not above, 15%, with a 2-fold reduction in energy dissipation upon microtubule depolymerization. Post hoc subgroup analysis revealed that myocardium from patients with HF with reduced ejection fraction were more fibrotic and elastic than myocardium from patients with HF with preserved ejection fraction, which were relatively more viscous. Colchicine reduced viscoelasticity in both HF with preserved ejection fraction and HF with reduced ejection fraction myocardium., Conclusions: Failing cardiomyocytes exhibit elevated viscosity and reducing microtubule density or detyrosination lowers viscoelastic resistance to diastolic stretch in human myocytes and myocardium. In failing myocardium, microtubules elevate stiffness over the typical working range of strains and strain rates, but exhibited diminishing effects with increasing length, consistent with an increasing contribution of the extracellular matrix or myofilament proteins at larger excursions. These studies indicate that a stabilized microtubule network provides a viscous impediment to diastolic stretch, particularly in HF.
- Published
- 2020
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31. Characterization of novel primary miRNA transcription units in human cells using Bru-seq nascent RNA sequencing.
- Author
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Bedi K, Paulsen MT, Wilson TE, and Ljungman M
- Abstract
MicroRNAs (miRNAs) are key contributors to gene regulatory networks. Because miRNAs are processed from RNA polymerase II transcripts, insight into miRNA regulation requires a comprehensive understanding of the regulation of primary miRNA transcripts. We used Bru-seq nascent RNA sequencing and hidden Markov model segmentation to map primary miRNA transcription units (TUs) across 32 human cell lines, allowing us to describe TUs encompassing 1443 miRNAs from miRBase and 438 from MirGeneDB. We identified TUs for 61 miRNAs with an unknown CAGE TSS signal for MirGeneDB miRNAs. Many primary transcripts containing miRNA sequences failed to generate mature miRNAs, suggesting that miRNA biosynthesis is under both transcriptional and post-transcriptional control. In addition to constitutive and cell-type specific TU expression regulated by differential promoter usage, miRNA synthesis can be regulated by transcription past polyadenylation sites (transcriptional read through) and promoter divergent transcription (PROMPTs). We identified 197 miRNA TUs with novel promoters, 97 with transcriptional read-throughs and 3 miRNA TUs that resemble PROMPTs in at least one cell line. The miRNA TU annotation data resource described here reveals a greater complexity in miRNA regulation than previously known and provides a framework for identifying cell-type specific differences in miRNA transcription in cancer and cell transition states., (© The Author(s) 2019. Published by Oxford University Press on behalf of NAR Genomics and Bioinformatics.)
- Published
- 2020
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32. Author Correction: Targeting cardiac fibrosis with engineered T cells.
- Author
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Aghajanian H, Kimura T, Rurik JG, Hancock AS, Leibowitz MS, Li L, Scholler J, Monslow J, Lo A, Han W, Wang T, Bedi K, Morley MP, Saldana RAL, Bolar NA, McDaid K, Assenmacher CA, Smith CL, Wirth D, June CH, Margulies KB, Jain R, Puré E, Albelda SM, and Epstein JA
- Abstract
An Amendment to this paper has been published and can be accessed via a link at the top of the paper.
- Published
- 2019
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33. Cardiomyocyte d-dopachrome tautomerase protects against heart failure.
- Author
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Ma Y, Su KN, Pfau D, Rao VS, Wu X, Hu X, Leng L, Du X, Piecychna M, Bedi K, Campbell SG, Eichmann A, Testani JM, Margulies KB, Bucala R, and Young LH
- Subjects
- Animals, Calcium, Cardiomegaly metabolism, Cardiomegaly pathology, Cytokines metabolism, Disease Models, Animal, Echocardiography, Gene Deletion, Gene Expression, Genetic Predisposition to Disease genetics, Humans, MAP Kinase Kinase Kinases metabolism, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Myocytes, Cardiac pathology, Recombinant Proteins, Signal Transduction, Transcriptome, Vascular Endothelial Growth Factor A metabolism, Heart Failure genetics, Heart Failure metabolism, Intramolecular Oxidoreductases genetics, Intramolecular Oxidoreductases metabolism, Myocytes, Cardiac enzymology, Myocytes, Cardiac metabolism
- Abstract
The mechanisms contributing to heart failure remain incompletely understood. d-dopachrome tautomerase (DDT) is a member of the macrophage migration inhibitory factor family of cytokines and is highly expressed in cardiomyocytes. This study examined the role of cardiomyocyte DDT in the setting of heart failure. Patients with advanced heart failure undergoing transplantation demonstrated decreased cardiac DDT expression. To understand the effect of loss of cardiac DDT in experimental heart failure, cardiomyocyte-specific DDT-KO (DDT-cKO) and littermate control mice underwent surgical transverse aortic constriction (TAC) to induce cardiac pressure overload. DDT-cKO mice developed more rapid cardiac contractile dysfunction, greater cardiac dilatation, and pulmonary edema after TAC. Cardiomyocytes from DDT-cKO mice after TAC had impaired contractility, calcium transients, and reduced expression of the sarcoplasmic reticulum calcium ATPase. The DDT-cKO hearts also exhibited diminished angiogenesis with reduced capillary density and lower VEGF-A expression after TAC. In pharmacological studies, recombinant DDT (rDDT) activated endothelial cell ERK1/2 and Akt signaling and had proangiogenic effects in vitro. The DDT-cKO hearts also demonstrated more interstitial fibrosis with enhanced collagen and connective tissue growth factor expression after TAC. In cardiac fibroblasts, rDDT had an antifibrotic action by inhibiting TGF-β-induced Smad-2 activation. Thus, endogenous cardiomyocyte DDT has pleiotropic actions that are protective against heart failure.
- Published
- 2019
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34. Targeting cardiac fibrosis with engineered T cells.
- Author
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Aghajanian H, Kimura T, Rurik JG, Hancock AS, Leibowitz MS, Li L, Scholler J, Monslow J, Lo A, Han W, Wang T, Bedi K, Morley MP, Linares Saldana RA, Bolar NA, McDaid K, Assenmacher CA, Smith CL, Wirth D, June CH, Margulies KB, Jain R, Puré E, Albelda SM, and Epstein JA
- Subjects
- Animals, Antigens, Surface immunology, Endomyocardial Fibrosis immunology, Fibroblasts immunology, Humans, Male, Mice, Ovalbumin immunology, Wound Healing, CD8-Positive T-Lymphocytes immunology, Endomyocardial Fibrosis therapy, Immunotherapy, Adoptive
- Abstract
Fibrosis is observed in nearly every form of myocardial disease
1 . Upon injury, cardiac fibroblasts in the heart begin to remodel the myocardium by depositing excess extracellular matrix, resulting in increased stiffness and reduced compliance of the tissue. Excessive cardiac fibrosis is an important factor in the progression of various forms of cardiac disease and heart failure2 . However, clinical interventions and therapies that target fibrosis remain limited3 . Here we demonstrate the efficacy of redirected T cell immunotherapy to specifically target pathological cardiac fibrosis in mice. We find that cardiac fibroblasts that express a xenogeneic antigen can be effectively targeted and ablated by adoptive transfer of antigen-specific CD8+ T cells. Through expression analysis of the gene signatures of cardiac fibroblasts obtained from healthy and diseased human hearts, we identify an endogenous target of cardiac fibroblasts-fibroblast activation protein. Adoptive transfer of T cells that express a chimeric antigen receptor against fibroblast activation protein results in a significant reduction in cardiac fibrosis and restoration of function after injury in mice. These results provide proof-of-principle for the development of immunotherapeutic drugs for the treatment of cardiac disease.- Published
- 2019
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35. The role of H3K79 methylation in transcription and the DNA damage response.
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Ljungman M, Parks L, Hulbatte R, and Bedi K
- Subjects
- Animals, Chromatin genetics, DNA Repair genetics, Genomic Instability genetics, Humans, Methylation, DNA Damage genetics, Histones genetics, Transcription, Genetic genetics
- Abstract
Chromatin plays a critical role in organizing and protecting DNA. However, chromatin acts as an impediment for transcription and DNA repair. Histone modifications, such as H3K79 methylation, promote transcription and genomic stability by enhancing transcription elongation and by serving as landing sites for proteins involved in the DNA damage response. This review summarizes the current understanding of the role of H3K79 methylation in transcription, how it affects genome stability and opportunities to develop impactful therapeutic interventions for cancer., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
36. Targeting MRTF/SRF in CAP2-dependent dilated cardiomyopathy delays disease onset.
- Author
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Xiong Y, Bedi K, Berritt S, Attipoe BK, Brooks TG, Wang K, Margulies KB, and Field J
- Subjects
- Animals, Cardiomyopathy, Dilated genetics, Cardiomyopathy, Dilated mortality, Cardiomyopathy, Dilated pathology, Carrier Proteins metabolism, Cytoskeleton drug effects, Cytoskeleton pathology, Disease Models, Animal, Female, Fetus, Heart drug effects, Heart embryology, Humans, Longevity drug effects, Male, Mice, Myocardium cytology, Myocardium metabolism, Myocardium pathology, Myocytes, Cardiac metabolism, Myocytes, Cardiac pathology, RNA-Seq, Serum Response Factor metabolism, Signal Transduction drug effects, Signal Transduction genetics, Time Factors, Transcription Factors metabolism, Anilides administration & dosage, Benzamides administration & dosage, Cardiomyopathy, Dilated drug therapy, Carrier Proteins genetics, Gene Expression Regulation, Developmental drug effects, Serum Response Factor antagonists & inhibitors
- Abstract
About one-third of dilated cardiomyopathy (DCM) cases are caused by mutations in sarcomere or cytoskeletal proteins. However, treating the cytoskeleton directly is not possible because drugs that bind to actin are not well tolerated. Mutations in the actin binding protein CAP2 can cause DCM and KO mice, either whole body (CAP2-KO) or cardiomyocyte-specific KOs (CAP2-CKO) develop DCM with cardiac conduction disease. RNA sequencing analysis of CAP2-KO hearts and isolated cardiomyocytes revealed overactivation of fetal genes, including serum response factor-regulated (SRF-regulated) genes such as Myl9 and Acta2 prior to the emergence of cardiac disease. To test if we could treat CAP2-KO mice, we synthesized and tested the SRF inhibitor CCG-1423-8u. CCG-1423-8u reduced expression of the SRF targets Myl9 and Acta2, as well as the biomarker of heart failure, Nppa. The median survival of CAP2-CKO mice was 98 days, while CCG-1423-8u-treated CKO mice survived for 116 days and also maintained normal cardiac function longer. These results suggest that some forms of sudden cardiac death and cardiac conduction disease are under cytoskeletal stress and that inhibiting signaling through SRF may benefit DCM by reducing cytoskeletal stress.
- Published
- 2019
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- View/download PDF
37. Suppression of detyrosinated microtubules improves cardiomyocyte function in human heart failure.
- Author
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Chen CY, Caporizzo MA, Bedi K, Vite A, Bogush AI, Robison P, Heffler JG, Salomon AK, Kelly NA, Babu A, Morley MP, Margulies KB, and Prosser BL
- Subjects
- Cell Proliferation, Desmin metabolism, Elasticity, Humans, Intermediate Filaments metabolism, Muscle Cells cytology, Muscle Cells metabolism, Myocardial Infarction, Proteomics, Up-Regulation, Viscosity, Heart Failure metabolism, Microtubules metabolism, Myocytes, Cardiac metabolism, Tyrosine metabolism
- Abstract
Detyrosinated microtubules provide mechanical resistance that can impede the motion of contracting cardiomyocytes. However, the functional effects of microtubule detyrosination in heart failure or in human hearts have not previously been studied. Here, we utilize mass spectrometry and single-myocyte mechanical assays to characterize changes to the cardiomyocyte cytoskeleton and their functional consequences in human heart failure. Proteomic analysis of left ventricle tissue reveals a consistent upregulation and stabilization of intermediate filaments and microtubules in failing human hearts. As revealed by super-resolution imaging, failing cardiomyocytes are characterized by a dense, heavily detyrosinated microtubule network, which is associated with increased myocyte stiffness and impaired contractility. Pharmacological suppression of detyrosinated microtubules lowers the viscoelasticity of failing myocytes and restores 40-50% of lost contractile function; reduction of microtubule detyrosination using a genetic approach also softens cardiomyocytes and improves contractile kinetics. Together, these data demonstrate that a modified cytoskeletal network impedes contractile function in cardiomyocytes from failing human hearts and that targeting detyrosinated microtubules could represent a new inotropic strategy for improving cardiac function.
- Published
- 2018
- Full Text
- View/download PDF
38. Abnormal RNA stability in amyotrophic lateral sclerosis.
- Author
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Tank EM, Figueroa-Romero C, Hinder LM, Bedi K, Archbold HC, Li X, Weskamp K, Safren N, Paez-Colasante X, Pacut C, Thumma S, Paulsen MT, Guo K, Hur J, Ljungman M, Feldman EL, and Barmada SJ
- Subjects
- Aged, Aged, 80 and over, C9orf72 Protein genetics, DNA-Binding Proteins genetics, Female, Fibroblasts metabolism, Green Fluorescent Proteins metabolism, Humans, Induced Pluripotent Stem Cells cytology, Male, Middle Aged, Mitochondria metabolism, Amyotrophic Lateral Sclerosis genetics, DNA-Binding Proteins metabolism, Frontotemporal Dementia genetics, Mutation, RNA Stability
- Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) share key features, including accumulation of the RNA-binding protein TDP-43. TDP-43 regulates RNA homeostasis, but it remains unclear whether RNA stability is affected in these disorders. We use Bru-seq and BruChase-seq to assess genome-wide RNA stability in ALS patient-derived cells, demonstrating profound destabilization of ribosomal and mitochondrial transcripts. This pattern is recapitulated by TDP-43 overexpression, suggesting a primary role for TDP-43 in RNA destabilization, and in postmortem samples from ALS and FTD patients. Proteomics and functional studies illustrate corresponding reductions in mitochondrial components and compensatory increases in protein synthesis. Collectively, these observations suggest that TDP-43 deposition leads to targeted RNA instability in ALS and FTD, and may ultimately cause cell death by disrupting energy production and protein synthesis pathways.
- Published
- 2018
- Full Text
- View/download PDF
39. Stability of hepatitis C virus RNA and anti-HCV antibody in air-dried and freeze-dried human plasma samples.
- Author
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Poe A, Duong NT, Bedi K, and Kodani M
- Subjects
- Freeze Drying, Hepatitis C blood, Hepatitis C diagnosis, Hepatitis C Antibodies blood, Humans, Immunoassay, Polymerase Chain Reaction, RNA, Viral, Reproducibility of Results, Sensitivity and Specificity, Specimen Handling, Viral Load, Hepacivirus immunology, Hepatitis C immunology, Hepatitis C virology, Hepatitis C Antibodies immunology
- Abstract
Diagnosis of hepatitis C virus (HCV) infection is based on testing for antibodies to HCV (anti-HCV), hepatitis C core antigen (HCV cAg) and HCV RNA. To ensure quality control (QC) and quality assurance (QA), proficiency panels are provided by reference laboratories and various international organizations, requiring costly dry ice shipments to maintain specimen integrity. Alternative methods of specimen preservation and transport can save on shipping and handling and help in improving diagnostics by facilitating QA/QC of various laboratories especially in resource limited countries. Plasma samples positive for anti-HCV and HCV RNA were either dried using dried tube specimens (DTS) method or lyophilization for varying durations of time and temperature. Preservation of samples using DTS method resulted in loss of anti-HCV reactivity for low-positive samples and did not generate enough volume for HCV RNA testing. Lyophilized samples tested positive for anti-HCV even after storage at 4 °C and 25 °C for 12 weeks. Further, HCV RNA was detectable in 5 of 5 (100%) samples over the course of 12 week storage at 4, 25, 37 and 45 °C. In conclusion, lyophilization of specimens maintains integrity of plasma samples for testing for markers of HCV infection and can be a potent mode of sharing proficiency samples without incurring huge shipping costs and avoids challenges with dry ice shipments between donor and recipient laboratories., (Copyright © 2017. Published by Elsevier B.V.)
- Published
- 2018
- Full Text
- View/download PDF
40. A Bifunctional MAPK/PI3K Antagonist for Inhibition of Tumor Growth and Metastasis.
- Author
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Galbán S, Apfelbaum AA, Espinoza C, Heist K, Haley H, Bedi K, Ljungman M, Galbán CJ, Luker GD, Dort MV, and Ross BD
- Subjects
- Animals, Apoptosis drug effects, Cell Line, Tumor, Cell Proliferation drug effects, Colorectal Neoplasms genetics, Colorectal Neoplasms pathology, Drug Resistance, Neoplasm genetics, Gene Expression Regulation, Neoplastic drug effects, Humans, Liver Neoplasms genetics, Liver Neoplasms pathology, Liver Neoplasms secondary, Melanoma genetics, Melanoma pathology, Mice, Mutation, Neoplasm Metastasis, Neoplasm Recurrence, Local drug therapy, Neoplasm Recurrence, Local genetics, Neoplasm Recurrence, Local pathology, Oncogene Protein v-akt genetics, PTEN Phosphohydrolase genetics, Phosphatidylinositol 3-Kinases genetics, Proto-Oncogene Proteins B-raf genetics, Signal Transduction drug effects, TOR Serine-Threonine Kinases genetics, Xenograft Model Antitumor Assays, Colorectal Neoplasms drug therapy, Enzyme Inhibitors administration & dosage, Liver Neoplasms drug therapy, Melanoma drug therapy, Protein Kinase Inhibitors administration & dosage
- Abstract
Responses to targeted therapies frequently are brief, with patients relapsing with drug-resistant tumors. For oncogenic MEK and BRAF inhibition, drug resistance commonly occurs through activation of PI3K/AKT/mTOR signaling and immune checkpoint modulation, providing a robust molecular target for concomitant therapy. Here, we evaluated the efficacy of a bifunctional kinase inhibitor (ST-162) that concurrently targets MAPK and PI3K signaling pathways. Treatment with ST-162 produced regression of mutant KRAS- or BRAF-addicted xenograft models of colorectal cancer and melanoma and stasis of BRAF/PTEN-mutant melanomas. Combining ST-162 with immune checkpoint blockers further increased efficacy in a syngeneic KRAS-mutant colorectal cancer model. Nascent transcriptome analysis revealed a unique gene set regulated by ST-162 related to melanoma metastasis. Subsequent mouse studies revealed ST-162 was a potent inhibitor of melanoma metastasis to the liver. These findings highlight the significant potential of a single molecule with multikinase activity to achieve tumor control, overcome resistance, and prevent metastases through modulation of interconnected cell signaling pathways. Mol Cancer Ther; 16(11); 2340-50. ©2017 AACR ., (©2017 American Association for Cancer Research.)
- Published
- 2017
- Full Text
- View/download PDF
41. Transcriptional and post-transcriptional regulation of the ionizing radiation response by ATM and p53.
- Author
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Venkata Narayanan I, Paulsen MT, Bedi K, Berg N, Ljungman EA, Francia S, Veloso A, Magnuson B, di Fagagna FD, Wilson TE, and Ljungman M
- Subjects
- Cell Line, DNA Damage radiation effects, Enhancer Elements, Genetic, Fibroblasts drug effects, Fibroblasts metabolism, Gene Expression Profiling, Humans, RNA Stability radiation effects, Transcriptional Activation, Ataxia Telangiectasia Mutated Proteins metabolism, Gene Expression Regulation radiation effects, RNA Processing, Post-Transcriptional, Radiation, Ionizing, Transcription, Genetic, Tumor Suppressor Protein p53 metabolism
- Abstract
In response to ionizing radiation (IR), cells activate a DNA damage response (DDR) pathway to re-program gene expression. Previous studies using total cellular RNA analyses have shown that the stress kinase ATM and the transcription factor p53 are integral components required for induction of IR-induced gene expression. These studies did not distinguish between changes in RNA synthesis and RNA turnover and did not address the role of enhancer elements in DDR-mediated transcriptional regulation. To determine the contribution of synthesis and degradation of RNA and monitor the activity of enhancer elements following exposure to IR, we used the recently developed Bru-seq, BruChase-seq and BruUV-seq techniques. Our results show that ATM and p53 regulate both RNA synthesis and stability as well as enhancer element activity following exposure to IR. Importantly, many genes in the p53-signaling pathway were coordinately up-regulated by both increased synthesis and RNA stability while down-regulated genes were suppressed either by reduced synthesis or stability. Our study is the first of its kind that independently assessed the effects of ionizing radiation on transcription and post-transcriptional regulation in normal human cells.
- Published
- 2017
- Full Text
- View/download PDF
42. Gene length as a biological timer to establish temporal transcriptional regulation.
- Author
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Kirkconnell KS, Magnuson B, Paulsen MT, Lu B, Bedi K, and Ljungman M
- Subjects
- Animals, Bromouracil analogs & derivatives, Conserved Sequence, Enhancer Elements, Genetic genetics, Evolution, Molecular, Fibroblasts metabolism, Humans, Male, Mice, MicroRNAs genetics, MicroRNAs metabolism, Models, Biological, Oligonucleotide Array Sequence Analysis, Serum metabolism, Serum Response Factor genetics, Serum Response Factor metabolism, Time Factors, Transcription Factors metabolism, Uridine analogs & derivatives, Uridine metabolism, Gene Expression Regulation, Genes, Transcription, Genetic
- Abstract
Transcriptional timing is inherently influenced by gene length, thus providing a mechanism for temporal regulation of gene expression. While gene size has been shown to be important for the expression timing of specific genes during early development, whether it plays a role in the timing of other global gene expression programs has not been extensively explored. Here, we investigate the role of gene length during the early transcriptional response of human fibroblasts to serum stimulation. Using the nascent sequencing techniques Bru-seq and BruUV-seq, we identified immediate genome-wide transcriptional changes following serum stimulation that were linked to rapid activation of enhancer elements. We identified 873 significantly induced and 209 significantly repressed genes. Variations in gene size allowed for a large group of genes to be simultaneously activated but produce full-length RNAs at different times. The median length of the group of serum-induced genes was significantly larger than the median length of all expressed genes, housekeeping genes, and serum-repressed genes. These gene length relationships were also observed in corresponding mouse orthologs, suggesting that relative gene size is evolutionarily conserved. The sizes of transcription factor and microRNA genes immediately induced after serum stimulation varied dramatically, setting up a cascade mechanism for temporal expression arising from a single activation event. The retention and expansion of large intronic sequences during evolution have likely played important roles in fine-tuning the temporal expression of target genes in various cellular response programs.
- Published
- 2017
- Full Text
- View/download PDF
43. Genome stability versus transcript diversity.
- Author
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Magnuson B, Bedi K, and Ljungman M
- Subjects
- Alternative Splicing, DNA Damage, DNA Replication, Gene Expression Profiling, Genome, Human, Humans, Protein Biosynthesis, Proteome, RNA, Messenger metabolism, DNA Repair, Genetic Variation, Genomic Instability, RNA, Messenger genetics, Transcriptome
- Abstract
Our genome is protected from the introduction of mutations by high fidelity replication and an extensive network of DNA damage response and repair mechanisms. However, the expression of our genome, via RNA and protein synthesis, allows for more diversity in translating genetic information. In addition, the splicing process has become less stringent over evolutionary time allowing for a substantial increase in the diversity of transcripts generated. The result is a diverse transcriptome and proteome that harbor selective advantages over a more tightly regulated system. Here, we describe mechanisms in place that both safeguard the genome and promote translational diversity, with emphasis on post-transcriptional RNA processing., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
44. Capturing the dynamic nascent transcriptome during acute cellular responses: The serum response.
- Author
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Kirkconnell KS, Paulsen MT, Magnuson B, Bedi K, and Ljungman M
- Abstract
Dynamic regulation of gene expression via signal transduction pathways is of fundamental importance during many biological processes such as cell state transitioning, cell cycle progression and stress responses. In this study we used serum stimulation as a cell response paradigm to apply the nascent RNA Bru-seq technique in order to capture early dynamic changes in the nascent transcriptome. Our data provides an unprecedented view of the dynamics of genome-wide transcription during the first two hours of serum stimulation in human fibroblasts. While some genes showed sustained induction or repression, other genes showed transient or delayed responses. Surprisingly, the dynamic patterns of induction and suppression of response genes showed a high degree of similarity, suggesting that these opposite outcomes are triggered by a common set of signals. As expected, early response genes such as those encoding components of the AP-1 transcription factor and those involved in the circadian clock were immediately but transiently induced. Surprisingly, transcription of important DNA damage response genes and histone genes were rapidly repressed. We also show that RNA polymerase II accelerates as it transcribes large genes and this was independent of whether the gene was induced or not. These results provide a unique genome-wide depiction of dynamic patterns of transcription of serum response genes and demonstrate the utility of Bru-seq to comprehensively capture rapid and dynamic changes of the nascent transcriptome., (© 2016. Published by The Company of Biologists Ltd.)
- Published
- 2016
- Full Text
- View/download PDF
45. Identifying transcription start sites and active enhancer elements using BruUV-seq.
- Author
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Magnuson B, Veloso A, Kirkconnell KS, de Andrade Lima LC, Paulsen MT, Ljungman EA, Bedi K, Prasad J, Wilson TE, and Ljungman M
- Subjects
- Computational Biology methods, Databases, Nucleic Acid, Genome, Human, Genomics methods, Humans, Molecular Sequence Annotation, Transcription Elongation, Genetic radiation effects, Transcription, Genetic radiation effects, Enhancer Elements, Genetic, Gene Expression Regulation radiation effects, Transcription Initiation Site, Ultraviolet Rays
- Abstract
BruUV-seq utilizes UV light to introduce transcription-blocking DNA lesions randomly in the genome prior to bromouridine-labeling and deep sequencing of nascent RNA. By inhibiting transcription elongation, but not initiation, pre-treatment with UV light leads to a redistribution of transcription reads resulting in the enhancement of nascent RNA signal towards the 5'-end of genes promoting the identification of transcription start sites (TSSs). Furthermore, transcripts associated with arrested RNA polymerases are protected from 3'-5' degradation and thus, unstable transcripts such as putative enhancer RNA (eRNA) are dramatically increased. Validation of BruUV-seq against GRO-cap that identifies capped run-on transcripts showed that most BruUV-seq peaks overlapped with GRO-cap signal over both TSSs and enhancer elements. Finally, BruUV-seq identified putative enhancer elements induced by tumor necrosis factor (TNF) treatment concomitant with expression of nearby TNF-induced genes. Taken together, BruUV-seq is a powerful new approach for identifying TSSs and active enhancer elements genome-wide in intact cells.
- Published
- 2015
- Full Text
- View/download PDF
46. Production of a Sindbis/Eastern Equine Encephalitis chimeric virus inactivated cell culture antigen.
- Author
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Goodman CH, Russell BJ, Velez JO, Laven JJ, Bagarozzi DA Jr, Moon JL, Bedi K, and Johnson BW
- Subjects
- Animals, Antibodies, Viral blood, Antigens, Viral immunology, Enzyme-Linked Immunosorbent Assay methods, Horses, Humans, Immunoglobulin M blood, Sindbis Virus growth & development, Virus Cultivation methods, Antigens, Viral genetics, Antigens, Viral isolation & purification, Encephalitis Virus, Eastern Equine genetics, Encephalomyelitis, Equine diagnosis, Sindbis Virus genetics
- Abstract
Eastern Equine Encephalitis virus (EEEV) is a medically important pathogen that can cause severe encephalitis in humans, with mortality rates ranging from 30 to 80%. Unfortunately there are no antivirals or licensed vaccines available for human use, and laboratory diagnosis is essential to differentiate EEEV infection from other pathogens with similar clinical manifestations. The Arboviral Diseases Branch (ADB) reference laboratory at the CDC Division of Vector-Borne Diseases (DVBD) produces reference antigens used in serological assays such as the EEEV immunoglobulin M antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA). However, EEEV is classified as a HHS select agent and requires biosafety level (BSL) three containment, limiting EEEV antigen production in non-select agent and BSL-2 laboratories. A recombinant Sindbis virus (SINV)/EEEV has been constructed for use under BSL-2 conditions and is not regulated as a select agent. Cell culture production of inactivated EEEV antigen from SINV/EEEV for use in the EEEV MAC-ELISA is reported here. Cell culture conditions and inactivation procedures were analyzed for SINV/EEEV using a recently developed antigen production algorithm, with the MAC-ELISA as the performance indicator., (Published by Elsevier B.V.)
- Published
- 2015
- Full Text
- View/download PDF
47. Survey of the knowledge, perception, and attitude of medical students at the University of Leeds toward organ donation and transplantation.
- Author
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Bedi KK, Hakeem AR, Dave R, Lewington A, Sanfey H, and Ahmad N
- Subjects
- Adolescent, Awareness, Curriculum, Data Collection, England, Female, Humans, Internet, Male, Perception, Surveys and Questionnaires, Tissue Donors supply & distribution, Young Adult, Health Knowledge, Attitudes, Practice, Organ Transplantation psychology, Students, Medical psychology, Tissue and Organ Procurement
- Abstract
Background: The shortage of organ donors is the key rate-limiting factor for organ transplantation in the United Kingdom. Many strategies have been proposed to increase donation; one strategy aims to improve awareness of organ donation and transplantation (ODT) among medical students. This survey seeks to investigate the knowledge, perceptions, and attitudes of the medical students in the United Kingdom toward ODT and the curriculum content., Methods: A 32-item online questionnaire was distributed to 957 medical students at the University of Leeds (October to December 2012)., Results: There were 216 (22.6%) respondents. Students were aware of kidney, heart, and liver transplantation (91.6%, 88.8%, and 86.5%). Awareness of small intestine (36.7%) and islet of Langerhans (33.0%) transplantation was poor. Students understood the term "brain stem death" (82.3%); however, they lacked understanding of criteria used for brain stem death testing (75.8%). Their perceptions and attitudes were favorable toward ODT; 43.3% of the students were unhappy with their current knowledge, and 87.6% of the students agree that ODT teaching should be included in the curriculum., Conclusions: Students have a basic understanding of ODT but lack detailed knowledge. They accept its importance and desire further teaching to supplement their current knowledge to be able to understand the issues related to ODT., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
48. Development of an algorithm for production of inactivated arbovirus antigens in cell culture.
- Author
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Goodman CH, Russell BJ, Velez JO, Laven JJ, Nicholson WL, Bagarozzi DA Jr, Moon JL, Bedi K, and Johnson BW
- Subjects
- Algorithms, Animals, Bunyaviridae chemistry, Bunyaviridae physiology, Cell Culture Techniques, Enzyme-Linked Immunosorbent Assay methods, Flaviviridae chemistry, Flaviviridae physiology, Humans, Togaviridae chemistry, Togaviridae physiology, Virus Cultivation methods, Antigens, Viral isolation & purification, Bunyaviridae growth & development, Flaviviridae growth & development, Reference Standards, Togaviridae growth & development, Virus Inactivation
- Abstract
Arboviruses are medically important pathogens that cause human disease ranging from a mild fever to encephalitis. Laboratory diagnosis is essential to differentiate arbovirus infections from other pathogens with similar clinical manifestations. The Arboviral Diseases Branch (ADB) reference laboratory at the CDC Division of Vector-Borne Diseases (DVBD) produces reference antigens used in serological assays such as the virus-specific immunoglobulin M antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA). Antigen production in cell culture has largely replaced the use of suckling mice; however, the methods are not directly transferable. The development of a cell culture antigen production algorithm for nine arboviruses from the three main arbovirus families, Flaviviridae, Togaviridae, and Bunyaviridae, is described here. Virus cell culture growth and harvest conditions were optimized, inactivation methods were evaluated, and concentration procedures were compared for each virus. Antigen performance was evaluated by the MAC-ELISA at each step of the procedure. The antigen production algorithm is a framework for standardization of methodology and quality control; however, a single antigen production protocol was not applicable to all arboviruses and needed to be optimized for each virus., (Published by Elsevier B.V.)
- Published
- 2014
- Full Text
- View/download PDF
49. Use of Bru-Seq and BruChase-Seq for genome-wide assessment of the synthesis and stability of RNA.
- Author
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Paulsen MT, Veloso A, Prasad J, Bedi K, Ljungman EA, Magnuson B, Wilson TE, and Ljungman M
- Subjects
- Animals, Bromouracil analogs & derivatives, Codon, Nonsense, DNA, Complementary genetics, Frameshift Mutation, Genome, Human, HeLa Cells, High-Throughput Nucleotide Sequencing, Humans, Hyaluronan Receptors genetics, Hyaluronan Receptors metabolism, K562 Cells, Kinetics, Molecular Sequence Annotation, RNA Splicing, RNA Stability, RNA, Messenger chemistry, RNA, Messenger genetics, RNA, Messenger isolation & purification, Retinoblastoma Protein genetics, Retinoblastoma Protein metabolism, Sequence Analysis, RNA, Staining and Labeling, Tumor Suppressor Protein p53 genetics, Tumor Suppressor Protein p53 metabolism, Uridine chemistry, RNA, Messenger biosynthesis, Uridine analogs & derivatives
- Abstract
Gene expression studies commonly examine total cellular RNA, which only provides information about its steady-state pool of RNA. It remains unclear whether differences in the steady-state reflects variable rates of transcription or RNA degradation. To specifically monitor RNA synthesis and degradation genome-wide, we developed Bru-Seq and BruChase-Seq. These assays are based on metabolic pulse-chase labeling of RNA using bromouridine (Bru). In Bru-Seq, recently labeled RNAs are sequenced to reveal spans of nascent transcription in the genome. In BruChase-Seq, cells are chased in uridine for different periods of time following Bru-labeling, allowing for the isolation of RNA populations of specific ages. Here we describe these methodologies in detail and highlight their usefulness in assessing RNA synthesis and stability as well as splicing kinetics with examples of specific genes from different human cell lines., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
50. Genome-wide transcriptional effects of the anti-cancer agent camptothecin.
- Author
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Veloso A, Biewen B, Paulsen MT, Berg N, Carmo de Andrade Lima L, Prasad J, Bedi K, Magnuson B, Wilson TE, and Ljungman M
- Subjects
- Base Sequence, DNA Helicases metabolism, DNA Repair Enzymes metabolism, DNA Topoisomerases, Type I metabolism, Fibroblasts metabolism, Gene Library, Genome genetics, Humans, Molecular Sequence Data, Poly-ADP-Ribose Binding Proteins, Sequence Analysis, DNA, Antineoplastic Agents, Phytogenic pharmacology, Camptothecin pharmacology, Genome drug effects, Transcription Elongation, Genetic drug effects
- Abstract
The anti-cancer drug camptothecin inhibits replication and transcription by trapping DNA topoisomerase I (Top1) covalently to DNA in a "cleavable complex". To examine the effects of camptothecin on RNA synthesis genome-wide we used Bru-Seq and show that camptothecin treatment primarily affected transcription elongation. We also observed that camptothecin increased RNA reads past transcription termination sites as well as at enhancer elements. Following removal of camptothecin, transcription spread as a wave from the 5'-end of genes with no recovery of transcription apparent from RNA polymerases stalled in the body of genes. As a result, camptothecin preferentially inhibited the expression of large genes such as proto-oncogenes, and anti-apoptotic genes while smaller ribosomal protein genes, pro-apoptotic genes and p53 target genes showed relative higher expression. Cockayne syndrome group B fibroblasts (CS-B), which are defective in transcription-coupled repair (TCR), showed an RNA synthesis recovery profile similar to normal fibroblasts suggesting that TCR is not involved in the repair of or RNA synthesis recovery from transcription-blocking Top1 lesions. These findings of the effects of camptothecin on transcription have important implications for its anti-cancer activities and may aid in the design of improved combinatorial treatments involving Top1 poisons.
- Published
- 2013
- Full Text
- View/download PDF
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