ERCC1 and XPF mediated upregulation of Fibronectin (FN) in Diabetes.

Abstract

ERCC1 and XPF mediated upregulation of Fibronectin (FN) in Diabetes. BIJU GEORGE*, SHALI CHEN, BIAO FENG, JANE CHIU AND SUBRATA CHAKRABARTI. Dept. of Pathology, Univ. of Western Ontario, London, ON. Excision Repair Cross Complimenting1 (ERCC-1) and Xeroderma Pigmentosum group F (XPF) are important DNA repair enzymes. They play important roles in aging, glucose metabolism and oxidative stress and demonstrate interactive relationships with Poly (ADP-Ribose) polymerase (PARP), another DNA repair protein, upregulated in diabetes. We studied the role of ERCC1 and XPF in glucose induced FN production. Human Umbilical Vein endothelial cells were grown in low (5mM) and high glucose (25mM) containing media. They were also exposed to siRNA against ERCC1 and XPF, histone deacetylase blocker TSA, PARP blocker ABA and p300 blocker Curcumin. Quantitative RT-PCR were performed for ERCC1, XPF, FN, PARP and p300 mRNA. High glucose led to upregulation of ERCC1, XPF, FN, PAPR, p300 mRNA levels compared to the cells in low glucose. ERCC1 and XPF silencing reduced such upregulation. ABA and curcumin also reduced both basal and glucose induced ERCC1 and XPF expression. TSA however, only prevented glucose induced ERCC1 and XPF upregulation. Western blots of ERCC1 and XPF from the nuclear proteins showed similar changes. Data from this study indicated that glucose induced upregulation of ERCC1 and XPF may lead to increased FN production via PARP, P300 pathway. These novel mechanisms may play important roles in diabetic complications. These studies were supported in part by CDA and CIHR 116