The transmembrane glycoprotein extracellular matrix metalloproteinase inducer (EMMPRIN), and the pleiotropic proinflammatory cytokine interleukin (IL)-18, play critical roles in myocardial remodeling, by inducing matrix degrading metalloproteinases (MMPs). Previously we showed that IL-18 induces EMMPRIN expression in cardiomyocytes via MyD88/IRAK4/TRAF6/JNKdependent Sp1 activation. Here in reciprocal studies we demonstrate that EMMPRIN is a potent inducer of IL-18 transcription, protein expression and protein secretion in primary mouse cardiomyocytes. We show for the first time that EMMPRIN stimulates the activation of NF-κB, AP-1, CREB, and ATF-2 in cardiomyocytes, and induces IL-18 expression via Rac1-dependent PI3K/Akt/IKK/NF-κB and MKK7/JNK/AP-1 signaling. Moreover, EMMPRIN induces robust time-dependent induction of various MMP mRNA. EMMPRIN also induces the mRNA of TIMPs 1 and 3, but in a delayed fashion. These results suggest that IL-18-induced EMMPRIN expression may favor net MMP expression and ECM destruction, and thus identify both as potential therapeutic targets in countering adverse myocardial remodeling.
Angiotensin-II (Ang-II) plays a key role in myocardial hypertrophy, remodeling and failure. We investigated whether Ang-II-induced cardiomyocyte hypertrophy is dependent on WNT1 inducible signaling pathway protein 1 (WISP1), a pro growth factor. Ang-II induced hypertrophy and WISP1 expression in neonatal rat cardiomyocytes (NRCM), effects that were significantly inhibited by pre-treatment with the AT1 antagonist losartan and by WISP1 knockdown. Further, Ang-II induced WISP1 was superoxide-dependent, and inhibited by DPI, an inhibitor of NADPH oxidases, and by knockdown of NOX2. AT1 physically associated with NOX2 both in vitro and in vivo, and Ang-II increased this interaction in vivo. Ang-II induced WISP1 expression via superoxide/Akt/GSK3β/β-catenin/TCF/LEF and by Akt-dependent CREB activation. Further, Ang-II also activated CREB via superoxide-mediated p38MAPK and ERK activation. Continuous infusion of Ang-II for 7 days induced myocardial hypertrophy in rats, and was associated with increased Akt, phospho-Akt, p-p38 MAPK, p-ERK1/2, and WISP1 expression. These results demonstrate that Ang-II induced cardiomyocyte hypertrophy is mediated through AT1, NOX2 and the induction of WISP1, and may involve the direct interaction of AT1 with NOX2. Thus targeting both WISP1 and NOX2 may have a therapeutic potential in improving cardiomyocyte survival and growth following myocardial injury and remodeling.
and the extracellular matrix metalloproteinase (MMP) inducer (EMMPRIN) stimulate the expression of proinflammatory cytokines and MMPs and are elevated in myocardial hypertrophy, remodeling, and failure. Here, we report several novel findings in primary cardiomyocytes treated with IL-18. First, IL-18 activated multiple transcription factors, including NF-B (p50 and p65), activator protein (AP)-1 (cFos, cJun, and JunD), GATA, CCAAT/enhancer-binding protein, myocyte-specific enhancerbinding factor, interferon regulatory factor-1, p53, and specific protein (Sp)-1. Second, IL-18 induced EMMPRIN expression via myeloid differentiation primary response gene 88/IL-1 receptor-associated kinase/TNF receptor-associated factor-6/JNK-dependent Sp1 activation. Third, IL-18 induced a number of MMP genes, particularly MMP-9, at a rapid rate as well as tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-3 at a slower rate. Finally, the IL-18 induction of MMP-9 was mediated in part via EMMPRIN and through JNK-and ERK-dependent AP-1 activation and p38 MAPK-dependent NF-B activation. These results suggest that the elevated expression of IL-18 during myocardial injury and inflammation may favor EMMPRIN and MMP induction and extracellular matrix degradation. Therefore, targeting IL-18 or its signaling pathways may be of potential therapeutic benefit in adverse remodeling. myocardial remodeling; extracellular matrix; extracellular matrix metalloproteinase inducer; matrix metalloproteinase; tissue inhibitor of metalloproteinase; c-Jun NH2 terminal kinase; specific protein-1; activator protein-1; nuclear factor-B
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.