Endothelin is a potent inhibitor of matrix metalloproteinase-2 secretion and activation in rat mesangial cells.

We examined the effects of endothelin (ET) on the activity of matrix metalloproteinase-2 (MMP-2) in cultured MCs. Addition of the ET(A) receptor antagonists or neutralizing anti-endothelin antibody into MC cultures markedly augmented the secretion and activation of MMP-2. On the contrary, addition of the exogenous ET-1 into MC culture significantly inhibited the synthesis of MMP-2 in both basal and cytokines (tumor necrosis factor-alpha and interferon-gamma) plus lipopolysaccharide-stimulated conditions. Furthermore, pretreatment of cells with exogenous ET-1 obviously prevented cytochalasin D-elicited activation of MMP-2, an effect that was completely abolished by ET(A) receptor antagonist, FR139317. In addition, ET-1 was found to be able to suppress the expression of membrane type-1 MMP (MT1-MMP) and promote the conversion of tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) from cell associated form to secreted form. The addition of recombinant TIMP-2 into the culture abrogated dose-dependently the cytochalasin D-elicited activation of MMP-2. These results suggest that ET is a potent inhibitor of MMP-2 secretion and activation in MCs. These novel findings may help us understand the subtle regulation of the synthesis and activation of MMP-2 in MCs. It also provides us with further insight into the pathophysiological mechanisms involving ET in the regulation of matrix turnover in glomerulus.