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Shu L, Sauter NS, Schulthess FT, Matveyenko AV, Oberholzer J, Maedler K. Statement of Retraction. Transcription Factor 7-Like 2 Regulates β-Cell Survival and Function in Human Pancreatic Islets. Diabetes 2017; 66:1729-1730. [PMID: 28356310 PMCID: PMC5440021 DOI: 10.2337/db17-rt06a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Shu L, Sauter NS, Schulthess FT, Matveyenko AV, Oberholzer J, Maedler K. Expression of Concern. Transcription Factor 7-Like 2 Regulates β-Cell Survival and Function in Human Pancreatic Islets. Diabetes 2008;57:645-653. DOI: 10.2337/db07-0847; and erratum. Diabetes 2014;63:3974. DOI: 10.2337/db14-er11. Diabetes 2016; 65:2461. [PMID: 27456622 DOI: 10.2337/db16-ec08] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Dharmadhikari G, Mühle M, Schulthess FT, Laue S, Oberholzer J, Pattou F, Kerr-Conte J, Maedler K. TOSO promotes β-cell proliferation and protects from apoptosis. Mol Metab 2012; 1:70-8. [PMID: 24024120 DOI: 10.1016/j.molmet.2012.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/03/2012] [Accepted: 08/03/2012] [Indexed: 01/09/2023] Open
Abstract
Decreased β-cell mass reflects a shift from quiescence/proliferation into apoptosis, it plays a crucial role in the pathophysiology of diabetes. A major attempt to restore β-cell mass and normoglycemia is to improve β-cell survival. Here we show that switching off the Fas pathway using Fas apoptotic inhibitory protein (Faim/TOSO), which regulates apoptosis upstream of caspase 8, blocked β-cell apoptosis and increased proliferation in human islets. TOSO was clearly expressed in pancreatic β-cells and down-regulated in T2DM. TOSO expression correlated with β-cell turnover; at conditions of improved survival, TOSO was induced. In contrast, TOSO downregulation induced β-cell apoptosis. Although TOSO overexpression resulted in a 3-fold induction of proliferation, proliferating β-cells showed a very limited capacity to undergo multiple rounds of replication. Our data suggest that TOSO is an important regulator of β-cell turnover and switches β-cell apoptosis into proliferation.
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Affiliation(s)
- G Dharmadhikari
- Centre for Biomolecular Interactions Bremen, University of Bremen, Germany
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Glas R, Sauter NS, Schulthess FT, Shu L, Oberholzer J, Maedler K. Purinergic P2X7 receptors regulate secretion of interleukin-1 receptor antagonist and beta cell function and survival. Diabetologia 2009; 52:1579-88. [PMID: 19396427 PMCID: PMC2709906 DOI: 10.1007/s00125-009-1349-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 03/03/2009] [Indexed: 01/06/2023]
Abstract
AIMS/HYPOTHESIS In obesity, beta cells activate compensatory mechanisms to adapt to the higher insulin demand. Interleukin-1 receptor antagonist (IL-1Ra) prevents obesity-induced hyperglycaemia and is a potent target for the treatment of diabetes, but the mechanisms of its secretion and regulation in obesity are unknown. In the present study, we hypothesise the regulation of IL-1Ra secretion by purinergic P2X(7) receptors in islets. METHODS Production and regulation of P2X(7) were studied in pancreatic sections from lean and obese diabetic patients, non-diabetic controls and in isolated islets. IL-1Ra, IL-1beta and insulin secretion, glucose tolerance and beta cell mass were studied in P2x7 (also known as P2Rx7)-knockout mice. RESULTS P2X(7) levels were elevated in beta cells of obese patients, but downregulated in patients with type 2 diabetes mellitus. Elevated glucose and non-esterified fatty acids rapidly activated P2X(7) and IL-1Ra secretion in human islets, and this was inhibited by P2X(7) blockade. In line with our results in vitro, P2x7-knockout mice had a lower capacity to secrete IL-1Ra. They exhibited severe and rapid hyperglycaemia, glucose intolerance and impaired beta cell function in response to a high-fat/high-sucrose diet, were unable to compensate by increasing their beta cell mass in response to the diet and showed increased beta cell apoptosis. CONCLUSIONS/INTERPRETATION Our study shows a tight correlation of P2X(7) activation, IL-1Ra secretion and regulation of beta cell mass and function. The increase in P2X(7) production is one mechanism that may explain how beta cells compensate by adapting to the higher insulin demand. Disturbances within that system may result in the progression of diabetes.
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Affiliation(s)
- R Glas
- Department of Medicine, Larry L. Hillblom Islet Research Center, UCLA, Los Angeles, CA, USA
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Schulthess FT, Katz S, Ardestani A, Kawahira H, Georgia S, Bosco D, Bhushan A, Maedler K. Deletion of the mitochondrial flavoprotein apoptosis inducing factor (AIF) induces beta-cell apoptosis and impairs beta-cell mass. PLoS One 2009; 4:e4394. [PMID: 19197367 PMCID: PMC2632884 DOI: 10.1371/journal.pone.0004394] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 12/15/2008] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Apoptosis is a hallmark of beta-cell death in both type 1 and type 2 diabetes mellitus. Understanding how apoptosis contributes to beta-cell turnover may lead to strategies to prevent progression of diabetes. A key mediator of apoptosis, mitochondrial function, and cell survival is apoptosis inducing factor (AIF). In the present study, we investigated the role of AIF on beta-cell mass and survival using the Harlequin (Hq) mutant mice, which are hypomorphic for AIF. METHODOLOGY/PRINCIPAL FINDINGS Immunohistochemical evaluation of pancreata from Hq mutant mice displayed much smaller islets compared to wild-type mice (WT). Analysis of beta-cell mass in these mice revealed a greater than 4-fold reduction in beta-cell mass together with an 8-fold increase in beta-cell apoptosis. Analysis of cell cycle dynamics, using BrdU pulse as a marker for cells in S-phase, did not detect significant differences in the frequency of beta-cells in S-phase. In contrast, double staining for phosphorylated Histone H3 and insulin showed a 3-fold increase in beta-cells in the G2 phase in Hq mutant mice, but no differences in M-phase compared to WT mice. This suggests that the beta-cells from Hq mutant mice are arrested in the G2 phase and are unlikely to complete the cell cycle. beta-cells from Hq mutant mice display increased sensitivity to hydrogen peroxide-induced apoptosis, which was confirmed in human islets in which AIF was depleted by siRNA. AIF deficiency had no effect on glucose stimulated insulin secretion, but the impaired effect of hydrogen peroxide on beta-cell function was potentiated. CONCLUSIONS/SIGNIFICANCE Our results indicate that AIF is essential for maintaining beta-cell mass and for oxidative stress response. A decrease in the oxidative phosphorylation capacity may counteract the development of diabetes, despite its deleterious effects on beta-cell survival.
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Affiliation(s)
- Fabienne T. Schulthess
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
- Larry L. Hillblom Islet Research Center, Department of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Sophie Katz
- Larry L. Hillblom Islet Research Center, Department of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Amin Ardestani
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
| | - Hiroshi Kawahira
- Larry L. Hillblom Islet Research Center, Department of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Senta Georgia
- Larry L. Hillblom Islet Research Center, Department of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, University of Geneva School of Medicine, Genèva, Switzerland
| | - Anil Bhushan
- Larry L. Hillblom Islet Research Center, Department of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Kathrin Maedler
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
- Larry L. Hillblom Islet Research Center, Department of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Schulthess FT, Paroni F, Sauter NS, Shu L, Ribaux P, Haataja L, Strieter RM, Oberholzer J, King CC, Maedler K. CXCL10 impairs beta cell function and viability in diabetes through TLR4 signaling. Cell Metab 2009; 9:125-39. [PMID: 19187771 DOI: 10.1016/j.cmet.2009.01.003] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 11/05/2008] [Accepted: 01/14/2009] [Indexed: 12/20/2022]
Abstract
In type 1 and type 2 diabetes (T1/T2DM), beta cell destruction by apoptosis results in decreased beta cell mass and progression of the disease. In this study, we found that the interferon gamma-inducible protein 10 plays an important role in triggering beta cell destruction. Islets isolated from patients with T2DM secreted CXCL10 and contained 33.5-fold more CXCL10 mRNA than islets from control patients. Pancreatic sections from obese nondiabetic individuals and patients with T2DM and T1DM expressed CXCL10 in beta cells. Treatment of human islets with CXCL10 decreased beta cell viability, impaired insulin secretion, and decreased insulin mRNA. CXCL10 induced sustained activation of Akt, JNK, and cleavage of p21-activated protein kinase 2 (PAK-2), switching Akt signals from proliferation to apoptosis. These effects were not mediated by the commonly known CXCL10 receptor CXCR3 but through TLR4. Our data suggest CXCL10 as a binding partner for TLR4 and as a signal toward beta cell failure in diabetes.
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Affiliation(s)
- Fabienne T Schulthess
- Larry L. Hillblom Islet Research Center, Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
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Mehrabian M, Schulthess FT, Nebohacova M, Castellani LW, Zhou Z, Hartiala J, Oberholzer J, Lusis AJ, Maedler K, Allayee H. Identification of ALOX5 as a gene regulating adiposity and pancreatic function. Diabetologia 2008; 51:978-88. [PMID: 18421434 PMCID: PMC2835627 DOI: 10.1007/s00125-008-1002-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Accepted: 02/08/2008] [Indexed: 11/27/2022]
Abstract
AIMS/HYPOTHESIS We previously used an integrative genetics approach to demonstrate that 5-lipoxygenase (5-LO) deficiency in mice (Alox5 (-/-)) protects against atherosclerosis despite increasing lipid levels and fat mass. In the present study, we sought to further examine the role of 5-LO in adiposity and pancreatic function. METHODS Alox5 (-/-) and wild-type (WT) mice were characterised with respect to adiposity and glucose/insulin metabolism using in vivo and in vitro approaches. The role of ALOX5 in pancreatic function in human islets was assessed through short interfering RNA (siRNA) knockdown experiments. RESULTS Beginning at 12 weeks of age, Alox5 (-/-) mice had significantly increased fat mass, plasma leptin levels and fasting glucose levels, but lower fasting insulin levels (p<0.05). Although Alox5 (-/-) mice did not exhibit insulin resistance, they had impaired insulin secretion in response to a bolus glucose injection. Histological analyses revealed that Alox5 (-/-) mice had increased islet area, beta cell nuclear size, and numbers of beta cells/mm(2) islet (p<0.05), indicative of both hyperplasia and hypertrophy. Basal and stimulated insulin secretion in isolated Alox5 (-/-) islets were significantly lower than in WT islets (p<0.05) and accompanied by a three- to fivefold decrease in the expression of the genes encoding insulin and pancreatic duodenal homeobox 1 (Pdx1). Direct perturbation of ALOX5 in isolated human islets with siRNA decreased insulin and PDX1 gene expression by 50% and insulin secretion by threefold (p<0.05). CONCLUSIONS/INTERPRETATION These results provide strong evidence for pleiotropic metabolic effects of 5-LO on adiposity and pancreatic function and may have important implications for therapeutic strategies targeting this pathway for the treatment of cardiovascular disease.
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Affiliation(s)
- M Mehrabian
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Sauter NS, Schulthess FT, Galasso R, Castellani LW, Maedler K. The antiinflammatory cytokine interleukin-1 receptor antagonist protects from high-fat diet-induced hyperglycemia. Endocrinology 2008; 149:2208-18. [PMID: 18239070 PMCID: PMC2734491 DOI: 10.1210/en.2007-1059] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Subclinical inflammation is a recently discovered phenomenon in type 2 diabetes. Elevated cytokines impair beta-cell function and survival. A recent clinical trial shows that blocking IL-1beta signaling by IL-1 receptor antagonist (IL-1Ra) improves beta-cell secretory function in patients with type 2 diabetes. In the present study, we provide further mechanisms of the protective role of IL-1Ra on the beta-cell. IL-1Ra prevented diabetes in vivo in C57BL/6J mice fed a high-fat/high-sucrose diet (HFD) for 12 wk; it improved glucose tolerance and insulin secretion. High-fat diet treatment increased serum levels of free fatty acids and of the adipokines resistin and leptin, which were reduced by IL-1Ra treatment. In addition, IL-1Ra counteracted adiponectin levels, which were decreased by high-fat feeding. Studies on isolated islets revealed that IL-1Ra specifically acted on the beta-cell. IL-1Ra protected islets from HFD treated animals from beta-cell apoptosis, induced beta-cell proliferation, and improved glucose-stimulated insulin secretion. Insulin mRNA was reduced in islets from mice fed a HFD but normalized in the IL-1Ra group. Our results show that IL-1Ra improves beta-cell survival and function, and support the potential role for IL-1Ra in the treatment of diabetes.
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Affiliation(s)
- Nadine S Sauter
- Larry L. Hillblom Islet Research Center, University of California Los Angeles, Los Angeles, California 90095-7345, USA
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Shu L, Sauter NS, Schulthess FT, Matveyenko AV, Oberholzer J, Maedler K. Transcription factor 7-like 2 regulates beta-cell survival and function in human pancreatic islets. Diabetes 2008; 57:645-53. [PMID: 18071026 DOI: 10.2337/db07-0847] [Citation(s) in RCA: 196] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Type 2 diabetes is characterized by impaired insulin secretion in response to increased metabolic demand. This defect in beta-cell compensation seems to result from the interplay between environmental factors and genetic predisposition. Genome-wide association studies reveal that common variants in transcription factor 7-like 2 (TCF7L2) are associated with increased risk of type 2 diabetes. The aim of the present study was to establish whether TCF7L2 plays a role in beta-cell function and/or survival. RESEARCH DESIGN AND METHODS To investigate the effects of TCFL7L2 depletion, isolated islets were exposed to TCF7L2 small interfering RNA (siRNA) versus scrambled siRNA, and beta-cell survival and function were examined. For TCF7L2 overexpression, islets were cultured in glucose concentrations of 5.5-33.3 mmol/l and the cytokine mix interleukin-1 beta/gamma-interferon with or without overexpression of TCF7L2. Subsequently, glucose-stimulated insulin secretion (GSIS), beta-cell apoptosis [by transferase-mediated dUTP nick-end labeling assay and Western blotting for poly(ADP-ribose) polymerase and Caspase-3 cleavage], and beta-cell proliferation (by Ki67 immunostaining) were analyzed. RESULTS Depleting TCF7L2 by siRNA resulted in a 5.1-fold increase in beta-cell apoptosis, 2.2-fold decrease in beta-cell proliferation (P < 0.001), and 2.6-fold decrease in GSIS (P < 0.01) in human islets. Similarly, loss of TCF7L2 resulted in impaired beta-cell function in mouse islets. In contrast, overexpression of TCF7L2 protected islets from glucose and cytokine-induced apoptosis and impaired function. CONCLUSIONS TCF7L2 is required for maintaining GSIS and beta-cell survival. Changes in the level of active TCF7L2 in beta-cells from carriers of at-risk allele may be the reason for defective insulin secretion and progression of type 2 diabetes.
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Affiliation(s)
- Luan Shu
- Larry L. Hillblom Islet Research Center, Department of Medicine, University of California, Los Angeles, California, USA
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Maedler K, Schulthess FT, Bielman C, Berney T, Bonny C, Prentki M, Donath MY, Roduit R. Glucose and leptin induce apoptosis in human beta-cells and impair glucose-stimulated insulin secretion through activation of c-Jun N-terminal kinases. FASEB J 2008; 22:1905-13. [PMID: 18263705 DOI: 10.1096/fj.07-101824] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
c-Jun N-terminal kinases (SAPK/JNKs) are activated by inflammatory cytokines, and JNK signaling is involved in insulin resistance and beta-cell secretory function and survival. Chronic high glucose concentrations and leptin induce interleukin-1beta (IL-1beta) secretion from pancreatic islets, an event that is possibly causal in promoting beta-cell dysfunction and death. The present study provides evidence that chronically elevated concentrations of leptin and glucose induce beta-cell apoptosis through activation of the JNK pathway in human islets and in insulinoma (INS 832/13) cells. JNK inhibition by the dominant inhibitor JNK-binding domain of IB1/JIP-1 (JNKi) reduced JNK activity and apoptosis induced by leptin and glucose. Exposure of human islets to leptin and high glucose concentrations leads to a decrease of glucose-induced insulin secretion, which was partly restored by JNKi. We detected an interplay between the JNK cascade and the caspase 1/IL-1beta-converting enzyme in human islets. The caspase 1 gene, which contains a potential activating protein-1 binding site, was up-regulated in pancreatic sections and in isolated islets from type 2 diabetic patients. Similarly, cultured human islets exposed to high glucose- and leptin-induced caspase 1 and JNK inhibition prevented this up-regulation. Therefore, JNK inhibition may protect beta-cells from the deleterious effects of high glucose and leptin in diabetes.
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Affiliation(s)
- Kathrin Maedler
- Larry L. Hillblom Islet Research Center, University of California, Los Angeles, California, USA.
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Sury MD, Frese-Schaper M, Mühlemann MK, Schulthess FT, Blasig IE, Täuber MG, Shaw SG, Christen S. Evidence that N-acetylcysteine inhibits TNF-alpha-induced cerebrovascular endothelin-1 upregulation via inhibition of mitogen- and stress-activated protein kinase. Free Radic Biol Med 2006; 41:1372-83. [PMID: 17023264 DOI: 10.1016/j.freeradbiomed.2006.07.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 07/13/2006] [Accepted: 07/19/2006] [Indexed: 12/20/2022]
Abstract
N-acetylcysteine (NAC) is neuroprotective in animal models of acute brain injury such as caused by bacterial meningitis. However, the mechanism(s) by which NAC exerts neuroprotection is unclear. Gene expression of endothelin-1 (ET-1), which contributes to cerebral blood flow decline in acute brain injury, is partially regulated by reactive oxygen species, and thus a potential target of NAC. We therefore examined the effect of NAC on tumor necrosis factor (TNF)-alpha-induced ET-1 production in cerebrovascular endothelial cells. NAC dose dependently inhibited TNF-alpha-induced preproET-1 mRNA upregulation and ET-1 protein secretion, while upregulation of inducible nitric oxide synthase (iNOS) was unaffected. Intriguingly, NAC had no effect on the initial activation (i.e., IkappaB degradation, nuclear p65 translocation, and Ser536 phosphorylation) of NF-kappaB by TNF-alpha. However, transient inhibition of NF-kappaB DNA binding suggested that NAC may inhibit ET-1 upregulation by inhibiting (a) parallel pathway(s) necessary for full transcriptional activation of NF-kappaB-mediated ET-1 gene expression. Similar to NAC, the MEK1/2 inhibitor U0126, the p38 inhibitor SB203580, and the protein kinase inhibitor H-89 selectively inhibited ET-1 upregulation without affecting nuclear p65 translocation, suggesting that NAC inhibits ET-1 upregulation via inhibition of mitogen- and stress-activated protein kinase (MSK). Supporting this notion, cotreatment with NAC inhibited the TNF-alpha-induced rise in MSK1 and MSK2 kinase activity, while siRNA knock-down experiments showed that MSK2 is the predominant isoform involved in TNF-alpha-induced ET-1 upregulation.
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Affiliation(s)
- Matthias D Sury
- Institute for Infectious Diseases, University of Berne, Friedbuehlstrasse 51, CH-3010 Berne, Switzerland
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