Poly(ADP-ribose) polymerase-1 in high glucose-induced epithelial-mesenchymal transition during peritoneal fibrosis

Peritoneal fibrosis is a major complication of continuous ambulatory peritoneal dialysis (CAPD). The present study tested the hypothesis that ADP-ribose polymerase-1 (PARP-1) may play a role in peritoneal epithelial-mesenchymal transition and fibrosis under high glucose conditions. High glucose (126 mmol/l)-induced peritoneal EMT and fibrosis via the PARP-1 mechanism was examined in the primary culture of rat peritoneal mesothelial cells (PMCs) and in the human peritoneal mesothelial cell line (HMrSv5) in the presence or absence of a PARP-1 inhibitor PJ34 (3x10-6 M) or by knocking down PARP-1 with the PARP-1 siRNA technique. High glucose significantly increased PARP-1 expression and EMT as demonstrated by de novo expression of a mesenchymal marker α-SMA and loss of epithelial phenotype E-cadherin by both rat and human PMC, resulting in peritoneal fibrosis including up-regulation of plasminogen activator inhibitor-1 (PAI-1), collagen I, and fibronectin mRNA and protein expression. All these fibrotic responses induced by high glucose were significantly inhibited by the PARP-1 inhibitor PJ34 (all P<0.05) or by knocking down PARP-1 with the siRNA technique. Results from this study suggested that high glucose stimulates peritoneal EMT and fibrosis via a PARP-1-dependent mechanism, and targeting the PARP-1 may represent an alternative therapeutic potential for CAPD-related peritoneal fibrosis.