Metformin modulates hyperglycaemia-induced endothelial senescence and apoptosis through SIRT1. Academic Article uri icon

Overview

abstract

  • BACKGROUND AND PURPOSE: Endothelial dysfunction can be detected at an early stage in the development of diabetes-related microvascular disease and is associated with accelerated endothelial senescence and ageing. Hyperglycaemia-induced oxidative stress is a major contributing factor to the development of endothelial dysfunction. Clinical data indicate that the hypoglycaemic agent, metformin, has an endothelial protective action; however, its molecular and cellular mechanisms remain elusive. In the present study, we have investigated the protective effect of metformin during hyperglycaemia-induced senescence in mouse microvascular endothelial cells (MMECs). EXPERIMENTAL APPROACH: MMECs were cultured in normal glucose (11 mM) and high glucose (HG; 40 mM) in the presence and absence of metformin (50 μM) for 72 h. The expression of sirtuin-1 (SIRT1) and senescence/apoptosis-associated markers was determined by immunoblotting and immunocyto techniques. SIRT1 expression was inhibited with appropriate siRNA. KEY RESULTS: Exposure of MMECs to HG significantly reduced SIRT1 protein expression, increased forkhead box O1 (FoxO-1) and p53 acetylation, increased p21 and decreased Bcl2 expression. In addition, senescence-associated β-galactosidase activity in MMECs was increased in HG. Treatment with metformin attenuated the HG-induced reduction of SIRT1 expression, modulated the SIRT1 downstream targets FoxO-1 and p53/p21, and protected endothelial cells from HG-induced premature senescence. However, following gene knockdown of SIRT1 the effects of metformin were lost. CONCLUSIONS AND IMPLICATIONS: HG-induced down-regulation of SIRT1 played a crucial role in diabetes-induced endothelial senescence. Furthermore, the protective effect of metformin against HG-induced endothelial dysfunction was partly due to its effects on SIRT1 expression and/or activity.

publication date

  • January 1, 2014

Research

keywords

  • Apoptosis
  • Cellular Senescence
  • Endothelium, Vascular
  • Hyperglycemia
  • Hypoglycemic Agents
  • Metformin
  • Sirtuin 1

Identity

PubMed Central ID

  • PMC3904269

Scopus Document Identifier

  • 84891275812

Digital Object Identifier (DOI)

  • 10.1111/bph.12496

PubMed ID

  • 24372553

Additional Document Info

volume

  • 171

issue

  • 2