Methylglyoxal augments intracellular oxidative stress in human aortic endothelial cells

Abstract

Methylglyoxal (MGO) is a non-enzymatic metabolite in the glycolytic pathway and its concentration in blood and tissues is elevated in diabetes and renal failure. MGO induces tissue injuries via ROS; however, the mechanism remains to be clarified. The present study examined the harmful actions of MGO. Human aortic endothelial cells were assessed under real-time fluorescent microscopy with continuous superfusion. Increases in intracellular ROS were measured with fluorescent indicator, 5-(and-6)-chloromethyl-2’,7’-dichlorodihydrofluorescein diacetate acetyl ester (DCFH-DA). The addition of MGO rapidly increased the ROS in a dose-dependent manner. The increment of DCF was entirely abolished by pre-treatment with superoxide anion scavenger and membrane-permeable catalase, indicating that MGO induces superoxide production. The increment was completely inhibited by 2-thenoyltrifluoroacetone or carbonyl cyanide 3-chlorophenylhydrazone and partially inhibited by N-methyl-L-arginine. These data suggest that MGO stimulates superoxide production from mitochondria and partially stimulates nitric oxide synthase in human endothelial cells.

Keywords::

• Methylglyoxal
• oxidative stress
• endothelial cell
• carbonyl stress

Acknowledgements

This work was supported by a Grant-in-Aid for Young Scientists from The Ministry of Education, Culture, Sports, Science and Technology of Japan (no. 18790156), the 21st Century Center of Excellence Program Special Research Grant from the Ministry of Education, Sports, and Culture, a research grant for cardiovascular research (13C-5) from the Ministry of Health, Labor, and Welfare of Japan, and the Japan Foundation for Applied Enzymology.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

This paper was first published online on Early Online on 26 October 2009.