Inhibition of calpain reduces oxidative stress and attenuates endothelial dysfunction in diabetes.

Bainian Chen,Tianqing Peng,Limei Shan,Gediminas Cepinskas,Inga Cepinskas,Peter W Schiller,Rui Ni,Futian Tang,Qing Zhao,Wang Wang

doi:10.1186/1475-2840-13-88

Abstract

AimsThe present study was to investigate the role of calpain in reactive oxygen species (ROS) production in endothelial cells and endothelium-dependent vascular dysfunction under experimental conditions of diabetes.Methods and resultsExposure to high glucose activated calpain, induced apoptosis and reduced nitric oxide (NO) production without changing eNOS protein expression, its phosphorylation and dimers formation in primary human umbilical vein endothelial cells (HUVECs). These effects of high glucose correlated with intracellular ROS production and mitochondrial superoxide generation. Selectively scavenging mitochondrial superoxide increased NO production in high glucose-stimulated HUVECs. Inhibition of calpain using over-expression of calpastatin or pharmacological calpain inhibitor prevented high glucose-induced ROS production, mitochondrial superoxide generation and apoptosis, which were concurrent with an elevation of NO production in HUVECs. In mouse models of streptozotocin-induced type-1 diabetes and OVE26 type-1 diabetic mice, calpain activation correlated with an increase in ROS production and peroxynitrite formation in aortas. Transgenic over-expression of calpastatin reduced ROS production and peroxynitrite formation in diabetic mice. In parallel, diabetes-induced reduction of endothelium-dependent relaxation in aortic ring was reversed by over-expression of calpastatin in mouse models of diabetes. However, the protective effect of calpastatin on endothelium-dependent relaxation was abrogated by eNOS deletion in diabetic mice.ConclusionsThis study suggests that calpain may play a role in vascular endothelial cell ROS production and endothelium-dependent dysfunction in diabetes. Thus, calpain may be an important therapeutic target to overcome diabetes-induced vascular dysfunction.

Highlights

Diabetes mellitus is one of the worldwide leading causes of death and long-term disability, resulting in huge social and economic burden
This study suggests that calpain may play a role in vascular endothelial cell reactive oxygen species (ROS) production and endothelium-dependent dysfunction in diabetes
Over-expression of calpastatin reduces ROS production in endothelial cells In agreement with a previous report [24], we showed that calpain activity was increased in human umbilical vein endothelial cells (HUVECs) by high glucose compared with normal glucose (P < 0.05, Figure 1A)

Summary

Introduction

Diabetes mellitus is one of the worldwide leading causes of death and long-term disability, resulting in huge social and economic burden. Because the endothelium is an important component of vascular homeostasis and the primary target of hyperglycemia and hyperlipidemia, endothelial dysfunction occurs in both animal models of glucose auto-oxidation, increased substrate flux through the polyol pathway and stimulation of eicosanoid metabolism, ROS is mainly produced by mitochondria, NADPH oxidase, xanthine oxidase and un-coupled nitric oxide (NO) synthase (NOS) [12,13,14] Both xanthine oxidase and NADPH oxidase have been reported to induce ROS production in diabetic vessels, which significantly contributes to endothelial dysfunction [15,16,17]. The regulation of ROS generation has not been fully addressed in diabetes

Methods

Results

Conclusion