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Contreras CJ, Mukherjee N, Branco RCS, Lin L, Hogan MF, Cai EP, Oberst AA, Kahn SE, Templin AT. RIPK1 and RIPK3 regulate TNFα-induced β-cell death in concert with caspase activity. Mol Metab 2022; 65:101582. [PMID: 36030035 PMCID: PMC9464965 DOI: 10.1016/j.molmet.2022.101582] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/16/2022] [Accepted: 08/19/2022] [Indexed: 12/02/2022] Open
Abstract
OBJECTIVE Type 1 diabetes (T1D) is characterized by autoimmune-associated β-cell loss, insulin insufficiency, and hyperglycemia. Although TNFα signaling is associated with β-cell loss and hyperglycemia in non-obese diabetic mice and human T1D, the molecular mechanisms of β-cell TNF receptor signaling have not been fully characterized. Based on work in other cell types, we hypothesized that receptor interacting protein kinase 1 (RIPK1) and receptor interacting protein kinase 3 (RIPK3) regulate TNFα-induced β-cell death in concert with caspase activity. METHODS We evaluated TNFα-induced cell death, caspase activity, and TNF receptor pathway molecule expression in immortalized NIT-1 and INS-1 β-cell lines and primary mouse islet cells in vitro. Our studies utilized genetic and small molecule approaches to alter RIPK1 and RIPK3 expression and caspase activity to interrogate mechanisms of TNFα-induced β-cell death. We used the β-cell toxin streptozotocin (STZ) to determine the susceptibility of Ripk3+/+ and Ripk3-/- mice to hyperglycemia in vivo. RESULTS Expression of TNF receptor signaling molecules including RIPK1 and RIPK3 was identified in NIT-1 and INS-1 β cells and isolated mouse islets at the mRNA and protein levels. TNFα treatment increased NIT-1 and INS-1 cell death and caspase activity after 24-48 h, and BV6, a small molecule inhibitor of inhibitor of apoptosis proteins (IAPs) amplified this TNFα-induced cell death. RIPK1 deficient NIT-1 cells were protected from TNFα- and BV6-induced cell death and caspase activation. Interestingly, small molecule inhibition of caspases with zVAD-fmk (zVAD) did not prevent TNFα-induced cell death in either NIT-1 or INS-1 cells. This caspase-independent cell death was increased by BV6 treatment and decreased in RIPK1 deficient NIT-1 cells. RIPK3 deficient NIT-1 cells and RIPK3 kinase inhibitor treated INS-1 cells were protected from TNFα+zVAD-induced cell death, whereas RIPK3 overexpression increased INS-1 cell death and promoted RIPK3 and MLKL interaction under TNFα+zVAD treatment. In mouse islet cells, BV6 or zVAD treatment promoted TNFα-induced cell death, and TNFα+zVAD-induced cell death was blocked by RIPK3 inhibition and in Ripk3-/- islet cells in vitro. Ripk3-/- mice were also protected from STZ-induced hyperglycemia and glucose intolerance in vivo. CONCLUSIONS RIPK1 and RIPK3 regulate TNFα-induced β-cell death in concert with caspase activity in immortalized and primary islet β cells. TNF receptor signaling molecules such as RIPK1 and RIPK3 may represent novel therapeutic targets to promote β-cell survival and glucose homeostasis in T1D.
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Affiliation(s)
- Christopher J Contreras
- Division of Endocrinology, Department of Medicine, Roudebush VA Medical Center and Indiana University School of Medicine, Indianapolis, IN, USA
| | - Noyonika Mukherjee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Renato C S Branco
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Li Lin
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Meghan F Hogan
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA, USA
| | - Erica P Cai
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN, USA
| | - Andrew A Oberst
- Department of Immunology, University of Washington, Seattle, WA, USA
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA, USA
| | - Andrew T Templin
- Division of Endocrinology, Department of Medicine, Roudebush VA Medical Center and Indiana University School of Medicine, Indianapolis, IN, USA; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA; Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN, USA; Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA.
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Sha W, Hu F, Bu S. Mitochondrial dysfunction and pancreatic islet β-cell failure (Review). Exp Ther Med 2020; 20:266. [PMID: 33199991 PMCID: PMC7664595 DOI: 10.3892/etm.2020.9396] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/17/2020] [Indexed: 02/07/2023] Open
Abstract
Pancreatic β-cells are the only source of insulin in humans. Mitochondria uses pyruvate to produce ATP as an intermediate link between glucose intake and insulin secretion in β-cells, in a process known as glucose-stimulated insulin secretion (GSIS). Previous studies have demonstrated that GSIS is negatively regulated by various factors in the mitochondria, including tRNALeu mutations, high p58 expression, reduced nicotinamide nucleotide transhydrogenase activity, abnormal levels of uncoupling proteins and reduced expression levels of transcription factors A, B1 and B2. Additionally, oxidative stress damages mitochondria and impairs antioxidant defense mechanisms, leading to the increased production of reactive oxygen species, which induces β-cell dysfunction. Inflammation in islets can also damage β-cell physiology. Inflammatory cytokines trigger the release of cytochrome c from the mitochondria via the NF-κB pathway. The present review examined the potential factors underlying mitochondrial dysfunction and their association with islet β-cell failure, which may offer novel insights regarding future strategies for the preservation of mitochondrial function and enhancement of antioxidant activity for individuals with diabetes mellitus.
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Affiliation(s)
- Wenxin Sha
- Diabetes Research Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Fei Hu
- Diabetes Research Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Shizhong Bu
- Diabetes Research Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
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Zheng Z, Liu S, Wang C, Wang C, Tang D, Shi Y, Han X. Association of genetic polymorphisms in CASP7 with risk of ischaemic stroke. Sci Rep 2019; 9:18627. [PMID: 31819117 PMCID: PMC6901581 DOI: 10.1038/s41598-019-55201-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 11/19/2019] [Indexed: 01/05/2023] Open
Abstract
Caspase 7 (CASP7) is located on chromosome 10q25.3 that has been identified to be a susceptibility locus of ischaemic stroke (IS) by genome-wide association study. Elevated CASP7 was observed in IS, acting as a key apoptotic mediator in the development of IS. The aim of this study was to investigate the association between genetic polymorphisms in CASP7 and risk of IS. The CASP7 polymorphisms were genotyped using a TaqMan allelic discrimination assay. The expression levels of CASP7 mRNA were examined using quantitative polymerase chain reaction and luciferase activity was analyzed using the Dual Luciferase reporter assay. The rs12415607 in the promoter of CASP7 was associated with a reduced risk of IS (AA vs. CC: adjusted OR = 0.55, 95% CI: 0.38-0.80, P = 0.002; CA/AA vs. CC: adjusted OR = 0.70, 95% CI: 0.54-0.91, P = 0.007; AA vs. CC/CA: adjusted OR = 0.64, 95% CI: 0.46-0.90, P = 0.01; A vs. C: adjusted OR = 0.74, 95% CI: 0.62-0.89, P = 0.001). Moreover, the rs12415607 AA genotype carriers exhibited lower levels of CASP7 mRNA and the rs12415607 A allele decreased the promoter activity. These findings indicate that the rs12415607 A allele induces lower levels of transcriptional activity and CASP7 mRNA, and thus is associated with a reduced risk of IS.
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Affiliation(s)
- Zhaoshi Zheng
- No. 1 Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, 130031, P.R. China
| | - Songyan Liu
- No. 1 Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, 130031, P.R. China
| | - Chuheng Wang
- Department of Clinical Medicine (Grade 2017 Student), School of Basic Medicine, Zhengzhou University, Zhengzhou, Henan, 450001, P.R. China
| | - Chunhui Wang
- Department of Neurosurgery, the Hospital of Jilin Province, Changchun, Jilin, 130031, P.R. China
| | - Dong Tang
- No. 1 Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, 130031, P.R. China
| | - Yuqing Shi
- No. 1 Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, 130031, P.R. China
| | - Xuemei Han
- No. 1 Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin, 130031, P.R. China.
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Zhao C, Shen Q. Overexpression of small ubiquitin‑like modifier 2 ameliorates high glucose‑induced reductions in cardiomyocyte proliferation via the transforming growth factor‑β/Smad pathway. Mol Med Rep 2018; 18:4877-4885. [PMID: 30280191 PMCID: PMC6236294 DOI: 10.3892/mmr.2018.9522] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 12/12/2017] [Indexed: 12/16/2022] Open
Abstract
Hyperglycemia may induce diabetic cardiomyopathy (DC). In the current study, the mechanism underlying the alleviation of high glucose (HG)-induced impairments in the proliferation of H9c2 embryo cardiomyocyte proliferation by small ubiquitin-like modifier 2 (SUMO2) overexpression was investigated. H9c2 cell morphology was identified as classical long shuttle type by optical microscopy. The viability of HG-injured H9c2 cells was evaluated by a Cell Counting Kit-8 assay and the results indicated that viability was inhibited in a dose-dependent (5.6, 10, 20 and 30 mmol/l) and time-dependent (6, 12 and 24 h) manner. H9c2 cells treated with 20 mmol/l HG for 24 h were selected for subsequent experiments due to the extent of injury caused at a low density. Flow cytometry was conducted to confirm cell cycle arrest between G1/S phases and apoptosis promotion in HG-injured H9c2 cells, and the subsequent alleviating effect of SUMO2 overexpression on these HG-induced effects. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were performed to detect mRNA and protein expression levels of cell cycle-and apoptosis-associated factors. The results indicated that the expression ofthe cell cycle-associated factors CyclinA2 and C-Myc was upregulated, and cyclin-dependent kinase inhibitor 1a was downregulated. The expression of the apoptosis-associated factor Bcl-2 was upregulated, while Bcl-2-associated X and caspase-3 expression was downregulated, by SUMO2 overexpression. Furthermore, the effect of SUMO2 overexpression on the transforming growth factor (TGF)-β/Smad pathway was also determined using RT-qPCR and western blot analysis. The results indicated the mRNA and protein levels of TGF-β1 and Smad3 in HG-injured H9c2 cells were significantly decreased following SUMO2 overexpression. Thus, the results demonstrated that overexpression of SUMO2 may alleviate H9c2 cardiomyocyte cell cycle arrest and apoptosis promotion induced by HG via regulation of cell cycle- and apoptosis-associated factors, as well as inhibition of the TGF-β/Smad pathway. These results may therefore provide a novel strategy for the protection of cardiomyocytes and may aid the diagnosis and prognosis of patients with DC.
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Affiliation(s)
- Chen Zhao
- Department of Geriatric, Shanghai Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200336, P.R. China
| | - Qile Shen
- Department of Geriatric, Shanghai Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200336, P.R. China
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