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Mechanisms of Beta-Cell Apoptosis in Type 2 Diabetes-Prone Situations and Potential Protection by GLP-1-Based Therapies. Int J Mol Sci 2021; 22:ijms22105303. [PMID: 34069914 PMCID: PMC8157542 DOI: 10.3390/ijms22105303] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 12/22/2022] Open
Abstract
Type 2 diabetes (T2D) is characterized by chronic hyperglycemia secondary to the decline of functional beta-cells and is usually accompanied by a reduced sensitivity to insulin. Whereas altered beta-cell function plays a key role in T2D onset, a decreased beta-cell mass was also reported to contribute to the pathophysiology of this metabolic disease. The decreased beta-cell mass in T2D is, at least in part, attributed to beta-cell apoptosis that is triggered by diabetogenic situations such as amyloid deposits, lipotoxicity and glucotoxicity. In this review, we discussed the molecular mechanisms involved in pancreatic beta-cell apoptosis under such diabetes-prone situations. Finally, we considered the molecular signaling pathways recruited by glucagon-like peptide-1-based therapies to potentially protect beta-cells from death under diabetogenic situations.
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Zheng J, Xie Y, Ren L, Qi L, Wu L, Pan X, Zhou J, Chen Z, Liu L. GLP-1 improves the supportive ability of astrocytes to neurons by promoting aerobic glycolysis in Alzheimer's disease. Mol Metab 2021; 47:101180. [PMID: 33556642 PMCID: PMC7905479 DOI: 10.1016/j.molmet.2021.101180] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/10/2021] [Accepted: 01/29/2021] [Indexed: 02/08/2023] Open
Abstract
Objective Astrocytes actively participate in energy metabolism in the brain, and astrocytic aerobic glycolysis disorder is associated with the pathology of Alzheimer's disease (AD). GLP-1 has been shown to improve cognition in AD; however, the mechanism remains unclear. The objectives of this study were to assess GLP-1's glycolytic regulation effects in AD and reveal its neuroprotective mechanisms. Methods The Morris water maze test was used to evaluate the effects of liraglutide (an analog of GLP-1) on the cognition of 4-month-old 5×FAD mice, and a proteomic analysis and Western blotting were used to assess the proteomic profile changes. We constructed an astrocytic model of AD by treating primary astrocytes with Aβ1-42. The levels of NAD+ and lactate were examined, and the oxidative levels were assessed by a Seahorse examination. Astrocyte-neuron co-culture was performed to evaluate the effects of GLP-1 on astrocytes’ neuronal support. Results GLP-1 improved cognition in 4-month-old 5×FAD mice by enhancing aerobic glycolysis and reducing oxidative phosphorylation (OXPHOS) levels and oxidative stress in the brain. GLP-1 also alleviated Aβ-induced glycolysis declines in astrocytes, which resulted in reduced OXPHOS levels and reactive oxygen species (ROS) production. The mechanism involved the activation of the PI3K/Akt pathway by GLP-1. Elevation in astrocytic glycolysis improved astrocyte cells’ support of neurons and promoted neuronal survival and axon growth. Conclusions Taken together, we revealed GLP-1's capacity to regulate astrocytic glycolysis, providing mechanistic insight into one of its neuroprotective roles in AD and support for the feasibility of energy regulation treatments for AD. GLP-1 mediates a metabolic shift from oxidative phosphorylation to aerobic glycolysis in Alzheimer's disease. GLP-1's mechanism of action involves activation of the PI3K/Akt pathway. GLP-1 enhances the supportive ability of astrocytes to neurons by promoting aerobic glycolysis.
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Affiliation(s)
- Jiaping Zheng
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Yunzhen Xie
- School of Pharmacy, Fujian Medical University, Fuzhou, 350122, China
| | - Lingjia Ren
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Liqin Qi
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Li Wu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China; Department of Hypertension, Luohe Central Hospital, China
| | - Xiaodong Pan
- Department of Neurology, Fujian Institute of Geriatrics, Fujian Medical University Union Hospital, Fuzhou, China
| | - Jianxing Zhou
- School of Pharmacy, Fujian Medical University, Fuzhou, 350122, China
| | - Zhou Chen
- School of Pharmacy, Fujian Medical University, Fuzhou, 350122, China.
| | - Libin Liu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350001, China.
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Sun Z, Li P, Wang X, Lai S, Qiu H, Chen Z, Hu S, Yao J, Shen J. GLP-1/GLP-1R Signaling Regulates Ovarian PCOS-Associated Granulosa Cells Proliferation and Antiapoptosis by Modification of Forkhead Box Protein O1 Phosphorylation Sites. Int J Endocrinol 2020; 2020:1484321. [PMID: 32655632 PMCID: PMC7321515 DOI: 10.1155/2020/1484321] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/18/2019] [Accepted: 12/27/2019] [Indexed: 12/23/2022] Open
Abstract
As the major cause of female anovulatory infertility, polycystic ovary syndrome (PCOS) affects a great proportion of women at childbearing age. Although glucagon-like peptide 1 receptor agonists (GLP-IRAs) show therapeutic effects for PCOS, its target and underlying mechanism remains elusive. In the present study, we identified that, both in vivo and in vitro, GLP-1 functioned as the regulator of proliferation and antiapoptosis of MGCs of follicle in PCOS mouse ovary. Furthermore, forkhead box protein O1 (FoxO1) plays an important role in the courses. Regarding the importance of granulosa cells (GCs) in oocyte development and function, the results from the current study could provide a more detailed illustration on the already known beneficial effects of GLP-1RAs on PCOS and support the future efforts to develop more efficient GLP-1RAs for PCOS treatment.
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Affiliation(s)
- Zhihua Sun
- Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China
- Panyu Central Hospital, Guangzhou, Guangdong, China
| | - Peiyi Li
- Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China
| | - Xiao Wang
- Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China
| | - Shuchang Lai
- Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China
| | - Hong Qiu
- Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China
| | - Zhi Chen
- Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China
| | - Shidi Hu
- Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China
| | - Jie Yao
- Medical Research Center, Shunde Hospital of Southern Medical University, Shunde, Guangdong, China
| | - Jie Shen
- Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, China
- Medical Research Center, Shunde Hospital of Southern Medical University, Shunde, Guangdong, China
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4
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Sun S, Zhang H, Shan K, Sun T, Lin M, Jia L, Chen YQ. Effect of Different Cereal Peptides on the Development of Type 1 Diabetes is Associated with Their Anti‐inflammatory Ability: In Vitro and In Vivo Studies. Mol Nutr Food Res 2019; 63:e1800987. [DOI: 10.1002/mnfr.201800987] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/20/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Suling Sun
- School of MedicineJiangnan University Wuxi 214122 P. R. China
- State Key Laboratory of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
- School of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
| | - Hao Zhang
- State Key Laboratory of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
- School of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
| | - Kai Shan
- School of MedicineJiangnan University Wuxi 214122 P. R. China
- State Key Laboratory of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
- School of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
| | - Tianjun Sun
- Department of Biochemistry & Molecular Biology & Center for Blood ResearchUniversity of British Columbia 2350 Health Sciences Mall Vancouver British Columbia V6T 1Z3 Canada
| | - Mengyuan Lin
- Wuxi Maternal and Child Health Hospital P. R. China
| | - Lingling Jia
- School of MedicineJiangnan University Wuxi 214122 P. R. China
- State Key Laboratory of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
- School of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
| | - Yong Q. Chen
- School of MedicineJiangnan University Wuxi 214122 P. R. China
- State Key Laboratory of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
- School of Food Science and TechnologyJiangnan University Wuxi 214122 P. R. China
- Departments of Cancer Biology and BiochemistryWake Forest School of Medicine Winston‐Salem NC 27157 USA
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Martins AD, Monteiro MP, Silva BM, Barros A, Sousa M, Carvalho RA, Oliveira PF, Alves MG. Metabolic dynamics of human Sertoli cells are differentially modulated by physiological and pharmacological concentrations of GLP-1. Toxicol Appl Pharmacol 2019; 362:1-8. [DOI: 10.1016/j.taap.2018.10.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 10/01/2018] [Accepted: 10/05/2018] [Indexed: 01/30/2023]
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Miao X, Gu Z, Liu Y, Jin M, Lu Y, Gong Y, Li L, Li C. The glucagon-like peptide-1 analogue liraglutide promotes autophagy through the modulation of 5'-AMP-activated protein kinase in INS-1 β-cells under high glucose conditions. Peptides 2018; 100:127-139. [PMID: 28712893 DOI: 10.1016/j.peptides.2017.07.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 07/04/2017] [Accepted: 07/07/2017] [Indexed: 01/07/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) is a potent therapeutic agent for the treatment of diabetes and has been proven to protect pancreatic β-cells from glucotoxicity; however, its mechanisms of action are not entirely understood. Autophagy is a dynamic lysosomal degradation process that can protect organisms against metabolic stress. Studies have shown that autophagy plays a protective role in the survival of pancreatic β-cells under high glucose conditions. In the present study, we explored the role of autophagy in GLP-1-induced protection of pancreatic β-cells exposed to high glucose. We demonstrated that the GLP-1 analogue liraglutide increased autophagy in rat INS-1 β-cells, and inhibition of autophagy abated the anti-apoptosis effect of liraglutide under high glucose conditions. Our results also showed that activation of 5'-AMP-activated protein kinase (AMPK) reduced liraglutide-induced autophagy enhancement and inhibited liraglutide-induced protection of INS-1 β-cells from high glucose. These data suggest that GLP-1 may protect β-cells from glucotoxicity through promoting autophagy by the modulation of AMPK. Deeper insight into the molecular mechanisms linking autophagy and GLP-1-induced β-cell protection may reveal novel therapeutic targets to preserve β-cell mass.
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Affiliation(s)
- Xinyu Miao
- Department of Geriatric Endocrinology, General Hospital of PLA, Beijing, China
| | - Zhaoyan Gu
- Department of Geriatric Endocrinology, General Hospital of PLA, Beijing, China
| | - Yu Liu
- Department of Geriatric Endocrinology, General Hospital of PLA, Beijing, China
| | - Mengmeng Jin
- Department of Geriatric Endocrinology, General Hospital of PLA, Beijing, China
| | - Yanhui Lu
- Department of Geriatric Endocrinology, General Hospital of PLA, Beijing, China
| | - Yanping Gong
- Department of Geriatric Endocrinology, General Hospital of PLA, Beijing, China
| | - Lin Li
- Department of Endocrinology, General Hospital of The PLA Rocket Force, Beijing, China
| | - Chunlin Li
- Department of Geriatric Endocrinology, General Hospital of PLA, Beijing, China.
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Zhang H, Liu R, Deng T, Wang X, Lang H, Qu Y, Duan J, Huang D, Ying G, Ba Y. The microRNA-124-iGluR2/3 pathway regulates glucagon release from alpha cells. Oncotarget 2017; 7:24734-43. [PMID: 27013590 PMCID: PMC5029737 DOI: 10.18632/oncotarget.8270] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/07/2016] [Indexed: 01/30/2023] Open
Abstract
Glucagon, secreted from islet alpha cells, plays an important role in regulating glucose homeostasis; however, the molecular mechanism underlying this process is not fully understood. Previous studies have demonstrated that miRNAs are involved in the function of alpha cells. Glutamate promotes glucagon secretion by mediating the opening of Ca2+ channels. In this present, iGluR2 and iGluR3 levels were significantly increased in fasting-treated mouse islets. Additional studies showed that miR-124-3p simultaneously regulates the expression of iGluR2 and iGluR3 through the direct targeting of mRNA 3’UTR of these two genes. The miR-124-iGluRs pathway also contributed to the high level of glucagon secretion through long-term high glucose levels. Thus, a novel pathway comprising miRNA, glutamate and iGluRs has been demonstrated to regulate the biological process of glucagon release.
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Affiliation(s)
- Haiyang Zhang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Rui Liu
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Ting Deng
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Xia Wang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Hongmei Lang
- Department of Endocrinology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, China
| | - Yanjun Qu
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Jingjing Duan
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Dingzhi Huang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Guoguang Ying
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Yi Ba
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
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Mao X, Chen H, Tang J, Wang L, Shu T. Hepcidin links gluco-toxicity to pancreatic beta cell dysfunction by inhibiting Pdx-1 expression. Endocr Connect 2017; 6:121-128. [PMID: 28179377 PMCID: PMC5424768 DOI: 10.1530/ec-16-0115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/08/2017] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Gluco-toxicity is a term used to convey the detrimental effect of hyperglycemia on β-cell function through impaired insulin synthesis. Although it is known that the expression and activity of several key insulin transcription regulators is inhibited, other molecular mechanisms that mediate gluco-toxicity are poorly defined. Our objective was to explore the role of hepcidin in β-cell gluco-toxicity. DESIGN We first confirmed that high glucose levels inhibited hepcidin expression in the mouse insulinoma cell line, MIN6. The downregulation of hepcidin decreased Pdx-1 expression, which reduced insulin synthesis. METHODS MIN6 cells were exposed to high glucose concentrations (33.3 mmol/L). Glucose-stimulated insulin secretion (GSIS) and serum hepcidin levels were measured by ELISA. The mRNA levels of insulin1, insulin2, Pdx-1 and hepcidin were measured by real-time polymerase chain reaction. Western blot analysis was used to detect the changes in PDX-1 expression. Transient overexpression with hepcidin was used to reverse the downregulation of Pdx-1 and insulin synthesis induced by gluco-toxicity. RESULTS Exposure of MIN6 cells to high glucose significantly decreased GSIS and inhibited insulin synthesis as well as Pdx-1 transcriptional activity and expression at both the mRNA and protein levels. High glucose also decreased hepcidin expression and secretion. Hepcidin overexpression in MIN6 cells partially reversed the gluco-toxicity-induced downregulation of Pdx-1 and insulin expression and improved GSIS. The restoration of insulin synthesis by transfection of a hepcidin overexpression plasmid confirmed the role of hepcidin in mediating the gluco-toxic inhibition of insulin synthesis. CONCLUSIONS Our observations suggest that hepcidin is associated with gluco-toxicity-reduced pancreatic β-cell insulin synthesis in type 2 diabetes by inhibiting Pdx-1 expression.
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Affiliation(s)
- Xuhua Mao
- Department of Clinical LaboratoryYixing People's Hospital, Yixing, Wuxi, Jiangsu, China
| | - Hucheng Chen
- Department of Nuclear MedicineNanjing Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, China
| | - Junmin Tang
- Department of Clinical LaboratoryYixing People's Hospital, Yixing, Wuxi, Jiangsu, China
| | - Liangliang Wang
- Department of NeurologyYixing People's Hospital Affiliated to Jiangsu University, Yixing, Wuxi, Jiangsu, China
| | - Tingting Shu
- Department of Central LaboratoryJiangsu Province Official Hospital, Nanjing, Jiangsu, China
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Oseguera Toledo ME, Gonzalez de Mejia E, Sivaguru M, Amaya-Llano SL. Common bean ( Phaseolus vulgaris L.) protein-derived peptides increased insulin secretion, inhibited lipid accumulation, increased glucose uptake and reduced the phosphatase and tensin homologue activation in vitro. J Funct Foods 2016. [DOI: 10.1016/j.jff.2016.09.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Ni Z, Ma X, Wang B, Wang H, Duan H, Li X, Jiang P, Tu P, Zhao Q, Zhu J, Li M. Pharmacological Effects and Pharmacokinetic Properties of a Dual-Function Peptide 5rolGLP-HV. Appl Biochem Biotechnol 2016; 181:483-494. [DOI: 10.1007/s12010-016-2225-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 08/26/2016] [Indexed: 12/12/2022]
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Abstract
Type two diabetes (T2D) is a challenging metabolic disorder for which a cure has not yet been found. Its etiology is associated with several phenomena, including significant loss of insulin-producing, beta cell (β cell) mass via progressive programmed cell death and disrupted cellular autophagy. In diabetes, the etiology of β cell death and the role of mitochondria are complex and involve several layers of mechanisms. Understanding the dynamics of those mechanisms could permit researchers to develop an intervention for the progressive loss of β cells. Currently, diabetes research has shifted toward rejuvenation and plasticity technology and away from the simplified approach of hormonal compensation. Diabetes research is currently challenged by questions such as how to enhance cell survival, decrease apoptosis and replenish β cell mass in diabetic patients. In this review, we discuss evidence that β cell development and mass formation are guided by specific signaling systems, particularly hormones, transcription factors, and growth factors, all of which could be manipulated to enhance mass growth. There is also strong evidence that β cells are dynamically active cells, which, under specific conditions such as obesity, can increase in size and subsequently increase insulin secretion. In certain cases of aggressive or advanced forms of T2D, β cells become markedly impaired, and the only alternatives for maintaining glucose homeostasis are through partial or complete cell grafting (the Edmonton protocol). In these cases, the harvesting of an enriched population of viable β cells is required for transplantation. This task necessitates a deep understanding of the pharmacological agents that affect β cell survival, mass, and function. The aim of this review is to initiate discussion about the important signals in pancreatic β cell development and mass formation and to highlight the process by which cell death occurs in diabetes. This review also examines the attempts that have been made to recover or increase cell mass in diabetic patients by using various pharmacological agents.
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Affiliation(s)
- Husnia I Marrif
- Department of Pharmacology, Faculty of Medicine, University of Benghazi Benghazi, Libya
| | - Salma I Al-Sunousi
- Department of Histology and Anatomy, Faculty of Medicine, University of Benghazi Benghazi, Libya
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Liu Z, Zhao N, Zhu H, Zhu S, Pan S, Xu J, Zhang X, Zhang Y, Wang J. Circulating interleukin-1β promotes endoplasmic reticulum stress-induced myocytes apoptosis in diabetic cardiomyopathy via interleukin-1 receptor-associated kinase-2. Cardiovasc Diabetol 2015; 14:125. [PMID: 26394923 PMCID: PMC4580368 DOI: 10.1186/s12933-015-0288-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 09/10/2015] [Indexed: 02/08/2023] Open
Abstract
Aim IL-1β was considered as an important inflammatory cytokine in diabetic cardiovascular complications. DCM is one of the major manifestations of diabetic cardiovascular complications whose specific mechanisms are still unclear. In this study, we investigated the role of IL-1β in myocytes apoptosis in DCM. Methods In the in vitro study, high- glucose medium and/or IL-1β were used to incubate the isolated primary myocytes. siRNA was used to knockdown the irak2 gene expression. Apoptosis was evaluated by Hoechst and TUNEL staining. In the in vivo study, DCM in rats was induced by STZ injection and confirmed by cardiac hemodynamic determinations. The IL-1 receptor antagonist, IL-1Ra was also used to treat DCM rats. Myocardial apoptosis was assessed by TUNEL assay. In both in vitro and in vivo studies, expression levels of GRP-78, IRAK-2 and CHOP were analyzed by Western Blotting. ELISA was employed to exam the IL-1β content in serum and cell supernatants. Results Myocytes were not identified as the source of IL-1β secretion under high- glucose incubation. High glucose incubation and/or IL-1β incubation elevated ER- stress mediated myocytes apoptosis which was attenuated by irak2 silencing. Dramatically increased circulating and myocardial IL-1β levels were found in DCM rats which stimulated activation of ER stress and lead to elevated myocytes apoptosis. The administration of IL-1Ra, however, attenuated IRAK2/CHOP induced apoptosis without affecting fasting blood glucose concentration. Conclusions Elevated circulating IL-1β contributed to promote ER stress- induced myocytes apoptosis by affecting IRAK-2/CHOP pathway in DCM.
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Affiliation(s)
- Zhongwei Liu
- Department of Cardiology, Shaanxi Provincial People's Hospital, No.257, Western Friendship Rd, Xi'an, People's Republic of China.
| | - Na Zhao
- Department of Cardiology, Shaanxi Provincial People's Hospital, No.257, Western Friendship Rd, Xi'an, People's Republic of China.
| | - Huolan Zhu
- Department of Cardiology, Shaanxi Provincial People's Hospital, No.257, Western Friendship Rd, Xi'an, People's Republic of China.
| | - Shunming Zhu
- Department of Cardiology, Shaanxi Provincial People's Hospital, No.257, Western Friendship Rd, Xi'an, People's Republic of China.
| | - Shuo Pan
- Department of Cardiology, Shaanxi Provincial People's Hospital, No.257, Western Friendship Rd, Xi'an, People's Republic of China.
| | - Jing Xu
- Department of Cardiology, Shaanxi Provincial People's Hospital, No.257, Western Friendship Rd, Xi'an, People's Republic of China.
| | - Xuejun Zhang
- Department of Cardiology, Shaanxi Provincial People's Hospital, No.257, Western Friendship Rd, Xi'an, People's Republic of China.
| | - Yong Zhang
- Department of Cardiology, Shaanxi Provincial People's Hospital, No.257, Western Friendship Rd, Xi'an, People's Republic of China.
| | - Junkui Wang
- Department of Cardiology, Shaanxi Provincial People's Hospital, No.257, Western Friendship Rd, Xi'an, People's Republic of China.
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