Aim: To investigate the thrombin mediated induction of gelatinase B (MMP-9) in mesangial cells (MC) and the underlying role of activator protein-1 (AP-1).
Methods: Cultured human mesangial cells were exposed to thrombin in the presence or absence of hirudin, curcumin, and c-fos antisense or sense oligonucleotides. Northern hybridization was employed to assess MMP-9 mRNA expression, and electrophoretic mobility shift assay (EMSA) for AP-1 DNA binding activity.
Results: The levels of MMP-9 mRNA in the cell treated with different doses of thrombin (500, 1500, and 4500 u/L, respectively) were 1.1, 3.3, and 4.8 times higher than that in the control, respectively. There was also an increase in AP-1 binding activity (3.5, 5.9, and 7.1 fold than that of the control) in accordance with MMP-9 mRNA levels in the presence of thrombin. Hirudin, curcumin, and c-fos antisense oligonucleotides could block thrombin-induced expression of MMP-9 mRNA as well as AP-1 binding activity.
Conclusion: Thrombin is a potent stimulator of MMP-9 gene expression in human mesangial cells, and the underlying intracellular events are mediated, at least partly, by AP-1 pathway.