Matrix metalloproteinase-2 contributes to tumor necrosis factor alpha induced apoptosis in cultured rat cardiac myocytes

Tumor necrosis factor alpha (TNFα) is associated with a higher risk of cardiovascular disease. Matrix metalloproteinase-2 (MMP-2) has been implicated in the pathophysiology of ischemic heart disease. However, the role of interactions between MMP-2 and TNFα, associated with cardiac apoptosis, is unknown. We hypothesized that MMP-2 will contribute to TNFα-induced myocardial apoptosis. After treatment with TNFα (1–20 ng/ml) for 24 h, or with TNFα (10 ng/ml) for 0, 6, 12, 24, or 48 h, MMP-2 activity, percent of TUNEL-positive myocytes, and DNA fragmentation dose, and time-dependently increased compared to control. However, TNFα blockade (neutralizing antibodies against human TNFα, 25 μg/ml) significantly reduced the activity of MMP-2 and markers of apoptosis induced by TNFα. Interestingly, MMP-2 antibody (30 μg/ml), or the MMP-2 inhibitors Doxycycline (Dox, 1–50 μmol/l) or GM6001 (GM, 10 μmol/l), prior to TNFα insult, decreased myocardial MMP-2 activity and reduced the percent of TUNEL-positive myocytes and DNA fragmentation. Moreover, MMP-2 inhibition reduced Bax expression and caspase3 activity, as well as increasing Bcl2 expression. MMP-2 inhibition was associated with decreased cardiac MMP-2 activity and decreased myocardial apoptosis induced by TNFα. These results suggest that MMP-2 contributes to TNFα-induced apoptosis in cultured rat cardiac myocytes.