Min Ding1, Qian-Hua Fang1, Yuan-Tao Cui1, Qi-Ling Shen1, Qian Liu1, Peng-Hua Wang1, De-Min Yu2, Chun-Jun Li3. 1. NHC Key Laboratory of Hormones and Development (Tianjin Medical University), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin 300070, PR China. 2. NHC Key Laboratory of Hormones and Development (Tianjin Medical University), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin 300070, PR China. Electronic address: yudemintij@126.com. 3. NHC Key Laboratory of Hormones and Development (Tianjin Medical University), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin 300070, PR China. Electronic address: li_chunjun@126.com.
Abstract
AIMS: High glucose (HG)-induced pancreatic β-cell apoptosis may be a major contributor to the progression of diabetes mellitus (DM). NADPH oxidase (NOX2) has been considered a crucial regulator in β-cell apoptosis. This study was designed to evaluate the impact of GLP-1 receptor agonist (GLP-1Ra) liraglutide on pancreatic β-cell apoptosis in diabetes and the underlying mechanisms involved. METHODS: The diabetic rat models induced by streptozotocin (STZ) and a high fat diet (HFD) received 12 weeks of liraglutide treatment. Hyperglycemic clamp test was carried out to evaluate β-cell function in vivo. Flow cytometry analysis was used to measure apoptosis rates in vitro. DCFH-DA method was used to detected ROS level in vivo and in vitro. RESULTS: Liraglutide significantly improved islet function and morphology in diabetic rats and decreased cell apoptosis rates. Thr183/Thr185 p-JNK1/2 and NOX2 levels reduced in diabetic rats and HG-induced INS-1 cell following liraglutide treatment. In addition, liraglutide upregulated the phosphorylation of AMPKα (p-AMPKα), which prevented NOX2 activation and alleviated HG-induced β-cell apoptosis. CONCLUSION: The p-AMPKα/NOX2/JNK1/2 pathway is essential for liraglutide to attenuate HG-induced β-cell apoptosis, which further proves that GLP-1Ras may become promising therapeutics for diabetes mellitus.
AIMS: High glucose (HG)-induced pancreatic β-cell apoptosis may be a major contributor to the progression of diabetes mellitus (DM). NADPH oxidase (NOX2) has been considered a crucial regulator in β-cell apoptosis. This study was designed to evaluate the impact of GLP-1 receptor agonist (GLP-1Ra) liraglutide on pancreatic β-cell apoptosis in diabetes and the underlying mechanisms involved. METHODS: The diabeticrat models induced by streptozotocin (STZ) and a high fat diet (HFD) received 12 weeks of liraglutide treatment. Hyperglycemic clamp test was carried out to evaluate β-cell function in vivo. Flow cytometry analysis was used to measure apoptosis rates in vitro. DCFH-DA method was used to detected ROS level in vivo and in vitro. RESULTS: Liraglutide significantly improved islet function and morphology in diabeticrats and decreased cell apoptosis rates. Thr183/Thr185 p-JNK1/2 and NOX2 levels reduced in diabeticrats and HG-induced INS-1 cell following liraglutide treatment. In addition, liraglutide upregulated the phosphorylation of AMPKα (p-AMPKα), which prevented NOX2 activation and alleviated HG-induced β-cell apoptosis. CONCLUSION: The p-AMPKα/NOX2/JNK1/2 pathway is essential for liraglutide to attenuate HG-induced β-cell apoptosis, which further proves that GLP-1Ras may become promising therapeutics for diabetes mellitus.