Knockdown of EMMPRIN improves adverse remodeling mediated by IL-18 in the post-infarcted heart.

Interleukin-18 (IL-18) exacerbates cardiac dysfunction following myocardial infarction (MI). Extracellular matrix metalloproteinase inducer (EMMPRIN) has been shown to exacerbate ventricular remodeling via induction of extracellular matrix metalloproteinase (MMP) synthesis. While up-regulation of EMMPRIN expression by IL-18 has been demonstrated in vitro, little is known regarding its in vivo effects. Here, we investigated the role of EMMPRIN in progressive post-infarct ventricular remodeling induced by IL-18. Cardiac function was impaired on echocardiography and organ weight was increased in mice receiving daily intraperitoneal injection of IL-18 following MI. Accompanying these adverse functional effect were increased EMMPRIN levels. Gene silencing of cardiac EMMPRIN by intramyocardial RNA interference rescued IL-18 mediated adverse effects on post-infarct cardiac function. Finally, EMMPRIN silencing reduced MMP-9 expression in the post-infarcted left ventricular myocardium. In conclusion, progressive post-infarct left ventricular remodeling induced by IL-18 can be reversed by gene silencing of EMMPRIN. Knock down of EMMPRIN may be a potential therapeutic strategy to abrogate the adverse effects of IL-18 on post-infarct left ventricular remodeling likely via MMP-9 inhibition.