Reactive oxygen species mediate TGF-?1-induced changing of plasmin activity in rat mesangial cells / 中国病理生理杂志

ABSTRACT

AIM: To investigate the role of reactive oxygen species (ROS) in transforming growth factor-?1 (TGF-?1)-induced regulation of plasminogen activator inhibitor-1 (PAI-1) expression and plasmin activity. METHODS: Growth arrested and synchronized rat mesangial cells were stimulated by TGF-?1. In some experiments,cells were pretreated with BSO or with antioxidant NAC. Intracellular ROS production was visualized using a fluorescent dye. PAI-1 protein secretion by mesangial cells was measured by Western blot and PAI-1 mRNA by both RT-PCR and Northern blot. Plasmin activity was determined using a synthetic fluorometric plasmin substrate. RESULTS: Exogenous TGF-?1 significantly increased intracellular ROS concentration and upregulated PAI-1 mRNA and protein expression in mesangial cells and reduced the plasmin activity. TGF-?1-induced upregulation of PAI-1 mRNA expression was exaggerated by BSO[DL-buthionine-(S,R)-sulfoximine]. NAC (N-acetylcysteine) effectively reversed TGF-?1-induced PAI-1 mRNA overexpression and plasmin activity decreasing. CONCLUSION: TGF-?1 increases intracellular ROS generation. ROS acts as a signaling molecular to mediate TGF-?1-induced PAI-1 overexpression and decrease in plasmin activity.