scholarly journals Imeglimin Amplifies Glucose-Stimulated Insulin Release from Diabetic Islets via a Distinct Mechanism of Action

2020 ◽  
Author(s):  
Sophie Hallakou-Bozec ◽  
Micheline Kergoat ◽  
Pascale Fouqueray ◽  
Sébastien Bolze ◽  
David E. Moller

ABSTRACTPancreatic islet β-cell dysfunction is characterized by defective glucose-stimulated insulin secretion (GSIS) and is a predominant component of the pathophysiology of diabetes. Imeglimin, a novel first-in-class small molecule tetrahydrotriazine drug candidate, improves glycemia and GSIS in preclinical models and clinical trials in patients with type 2 diabetes; however, the mechanism by which it restores β-cell function is unknown. Here, we show that Imeglimin acutely and directly amplifies GSIS in islets isolated from rodents with Type 2 diabetes via a mode of action that is distinct from other known therapeutic approaches. The underlying mechanism involves increases in the cellular nicotinamide adenine dinucleotide (NAD+) pool – potentially via the salvage pathway and induction of nicotinamide phosphoribosyltransferase (NAMPT) along with augmentation of glucose-induced ATP levels. Further, additional results suggest that NAD+ conversion to a second messenger, cyclic ADP ribose (cADPR), via cyclic ADP ribose hydrolase (CD38) is required for Imeglimin’s effects in islets, thus representing a potential link between increased NAD+ and enhanced glucose-induced Ca2+ mobilization which - in turn - is known to drive insulin granule exocytosis. Collectively, these findings implicate a novel mode of action for Imeglimin that explains its ability to effectively restore β-cell function and provides for a new approach to treat patients suffering from Type 2 diabetes.

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0241651
Author(s):  
Sophie Hallakou-Bozec ◽  
Micheline Kergoat ◽  
Pascale Fouqueray ◽  
Sébastien Bolze ◽  
David E. Moller

Pancreatic islet β-cell dysfunction is characterized by defective glucose-stimulated insulin secretion (GSIS) and is a predominant component of the pathophysiology of diabetes. Imeglimin, a novel first-in-class small molecule tetrahydrotriazine drug candidate, improves glycemia and GSIS in preclinical models and clinical trials in patients with Type 2 diabetes; however, the mechanism by which it restores β-cell function is unknown. Here, we show that imeglimin acutely and directly amplifies GSIS in islets isolated from rodents with Type 2 diabetes via a mode of action that is distinct from other known therapeutic approaches. The underlying mechanism involves increases in the cellular nicotinamide adenine dinucleotide (NAD+) pool—potentially via the salvage pathway and induction of nicotinamide phosphoribosyltransferase (NAMPT) along with augmentation of glucose-induced ATP levels. Further, additional results suggest that NAD+ conversion to a second messenger, cyclic ADP ribose (cADPR), via ADP ribosyl cyclase/cADPR hydrolase (CD38) is required for imeglimin’s effects in islets, thus representing a potential link between increased NAD+ and enhanced glucose-induced Ca2+ mobilization which—in turn—is known to drive insulin granule exocytosis. Collectively, these findings implicate a novel mode of action for imeglimin that explains its ability to effectively restore—β-cell function and provides for a new approach to treat patients suffering from Type 2 diabetes.


PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0162204 ◽  
Author(s):  
Lei Zhuang ◽  
Jian-bin Su ◽  
Xiu-lin Zhang ◽  
Hai-yan Huang ◽  
Li-hua Zhao ◽  
...  

Author(s):  
Hayat Aljaibeji ◽  
Noha Mousaad Elemam ◽  
Abdul Khader Mohammed ◽  
Hind Hasswan ◽  
Mahammad Al Thahyabat ◽  
...  

Abstract Let7b-5p is a member of the Let-7 miRNA family and one of the top expressed miRNAs in human islets that implicated in glucose homeostasis. The levels of Let7b-5p in type 2 diabetes (T2DM) patients or its role in β-cell function is still unclear. In the current study, we measured the serum levels of let7b-5p in Emirati patients with T2DM (with/without complications) and control subjects. Overexpression or silencing of let7b-5p in INS-1 (832/13) cells was performed to investigate the impact on insulin secretion, content, cell viability, apoptosis, and key functional genes. We found that serum levels of let7b-5p are significantly (p<0.05) higher in T2DM-patients or T2DM with complications compared to control subjects. Overexpression of let7b-5p increased insulin content and decreased glucose-stimulated insulin secretion, whereas silencing of let7b-5p reduced insulin content and secretion. Modulation of the expression levels of let7b-5p did not influence cell viability nor apoptosis. Analysis of mRNA and protein expression of hallmark genes in let7b-5p transfected cells revealed a marked dysregulation of Insulin, Pancreatic And Duodenal Homeobox 1 (PDX1), glucokinase (GCK), glucose transporter 2 (GLUT2), and INSR. In conclusion, an appropriate level of let7b-5p is essential to maintain β-cell function and may be regarded as a biomarker for T2DM.


Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3328
Author(s):  
Eloisa Aparecida Vilas-Boas ◽  
Davidson Correa Almeida ◽  
Leticia Prates Roma ◽  
Fernanda Ortis ◽  
Angelo Rafael Carpinelli

A high caloric intake, rich in saturated fats, greatly contributes to the development of obesity, which is the leading risk factor for type 2 diabetes (T2D). A persistent caloric surplus increases plasma levels of fatty acids (FAs), especially saturated ones, which were shown to negatively impact pancreatic β-cell function and survival in a process called lipotoxicity. Lipotoxicity in β-cells activates different stress pathways, culminating in β-cells dysfunction and death. Among all stresses, endoplasmic reticulum (ER) stress and oxidative stress have been shown to be strongly correlated. One main source of oxidative stress in pancreatic β-cells appears to be the reactive oxygen species producer NADPH oxidase (NOX) enzyme, which has a role in the glucose-stimulated insulin secretion and in the β-cell demise during both T1 and T2D. In this review, we focus on the acute and chronic effects of FAs and the lipotoxicity-induced β-cell failure during T2D development, with special emphasis on the oxidative stress induced by NOX, the ER stress, and the crosstalk between NOX and ER stress.


Healthcare ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1010
Author(s):  
Wei-Hao Hsu ◽  
Chin-Wei Tseng ◽  
Yu-Ting Huang ◽  
Ching-Chao Liang ◽  
Mei-Yueh Lee ◽  
...  

Prediabetes should be viewed as an increased risk for diabetes and cardiovascular disease. In this study, we investigated its prevalence among the relatives and spouses of patients with type 2 diabetes or risk factors for prediabetes, insulin resistance, and β-cell function. A total of 175 individuals were included and stratified into three groups: controls, and relatives and spouses of type 2 diabetic patients. We compared clinical characteristics consisting of a homeostatic model assessment for insulin resistance (HOMA-IR) and beta cell function (HOMA-β), a quantitative insulin sensitivity check index (QUICKI), and triglyceride glucose (TyG) index. After a multivariable linear regression analysis, the relative group was independently correlated with high fasting glucose, a high TyG index, and low β-cell function; the relatives and spouses were independently associated with a low QUICKI. The relatives and spouses equally had a higher prevalence of prediabetes. These study also indicated that the relatives had multiple factors predicting the development of diabetes mellitus, and that the spouses may share a number of common environmental factors associated with low insulin sensitivity.


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