Regulation of Metallothionein Gene Expression by Oxidative Stress and HGF

Abstract

Abstract: : Purpose: Metallothioneins (MT) are a group of ubiquitous low-molecular-weight proteins that provide cellular protection from reactive forms of oxygen and other stress conditions. The purpose of this study was to investigate the effect of oxidative stress on metallothionein-1 mRNA expression in human retinal pigment epithelial cells (RPE) and how this effect is modulated by hepatocyte growth factor (HGF). Methods: Confluent RPE cells were treated with 100µM tert-­butyl hydroperoxide (tBH) for 1 and 5 hours. Identical treatments were performed on confluent cells pretreated with 20ng/ml HGF for 24 hrs. Relative MT-1 mRNA expression was measured by using real-time polymerase chain reaction (PCR). Results: The addition of tBH increased the MT expression in RPE cells by 2-fold and 8-fold with 1 hour and 5 hours treatment, respectively. When cells were pretreated with HGF, tBH did not increase MT expression by 1 hour. However, in the presence of HGF, MT expression was magnified to 16-fold with 5 hours tBH treatment. Conclusions: The stimulation of MT gene expression by oxidant stress may represent an important response to protect RPE from oxidant injury. HGF may promote the protective effect by amplifying this response.

Keywords: oxidation/oxidative or free radical damage • gene/expression