Advanced glycation end-products induce apoptosis in pancreatic islet endothelial cells via NF-κB-activated cyclooxygenase-2/prostaglandin E2 up-regulation.

Kuo-Cheng Lan,Shing Hwa Liu,Kuo-Tong Huang,Chia-Wei Kao,Keh-Sung Tsai,Chen-Yuan Chiu,Ching-Chia Wang,Meei-Ling Sheu,Kuo-How Huang,Garyfalia Drossopoulou

doi:10.1371/journal.pone.0124418

Abstract

Microvascular complications eventually affect nearly all patients with diabetes. Advanced glycation end-products (AGEs) resulting from hyperglycemia are a complex and heterogeneous group of compounds that accumulate in the plasma and tissues in diabetic patients. They are responsible for both endothelial dysfunction and diabetic vasculopathy. The aim of this study was to investigate the cytotoxicity of AGEs on pancreatic islet microvascular endothelial cells. The mechanism underlying the apoptotic effect of AGEs in pancreatic islet endothelial cell line MS1 was explored. The results showed that AGEs significantly decreased MS1 cell viability and induced MS1 cell apoptosis in a dose-dependent manner. AGEs dose-dependently increased the expressions of cleaved caspase-3, and cleaved poly (ADP-ribose) polymerase in MS1 cells. Treatment of MS1 cells with AGEs also resulted in increased nuclear factor (NF)-κB-p65 phosphorylation and cyclooxygenase (COX)-2 expression. However, AGEs did not affect the expressions of endoplasmic reticulum (ER) stress-related molecules in MS1 cells. Pretreatment with NS398 (a COX-2 inhibitor) to inhibit prostaglandin E2 (PGE2) production reversed the induction of cleaved caspase-3, cleaved PARP, and MS1 cell viability. Moreover, AGEs significantly increased the receptor for AGEs (RAGE) protein expression in MS1 cells, which could be reversed by RAGE neutralizing antibody. RAGE Neutralizing antibody could also reverse the induction of cleaved caspase-3 and cleaved PARP and decreased cell viability induced by AGEs. These results implicate the involvement of NF-κB-activated COX-2/PGE2 up-regulation in AGEs/RAGE-induced islet endothelial cell apoptosis and cytotoxicity. These findings may provide insight into the pathological processes within the pancreatic islet microvasculature induced by AGEs accumulation.

Highlights

Diabetes mellitus (DM) is a multifactorial disease characterized by hyperglycemia and glucose intolerance due to insulin deficiency, impaired effectiveness of insulin action, or both [1]
MS1 cells were treated with various concentrations of Advanced glycation end-products (AGEs) (25–200 μg/mL) for 24 h to examine the cytotoxic effect of AGEs
MS1 cells were incubated with various concentrations of AGEs (25–200 μg/mL) for 24 h to examine whether apoptosis was involved in AGEs-induced cytotoxicity

Summary

Introduction

Diabetes mellitus (DM) is a multifactorial disease characterized by hyperglycemia and glucose intolerance due to insulin deficiency, impaired effectiveness of insulin action, or both [1]. Diabetic vascular complications are divided into two categories: macrovascular and microvascular complications. The atherosclerosis of large vessels is associated with macrovascular diseases in diabetes, which result in coronary artery diseases, stroke, and peripheral vascular diseases [2]. Endothelial dysfunction is thought to play a prominent role in the pathogenesis of diabetic vascular complications. These complications are characterized by changes in proliferation, barrier function, adhesion of circulating cells, and sensitivity to apoptosis [4,5,6]. Increased production of reactive oxygen species resulting in oxidative stress, cellular injury, and apoptosis occur in diabetes [8,9,10]. Cyclooxygenase-2 (COX2) activation is associated with high glucose (hyperglycemia)-induced endothelial cell apoptosis and regulated by nuclear factor (NF)-κB signaling [11]

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