J Mol Cell Cardiol. 2010 Jun;48(6):1060-70. doi: 10.1016/j.yjmcc.2009.11.020. Epub 2010 Jan 12.

Netrin-1 prevents ischemia/reperfusion-induced myocardial infarction via a DCC/ERK1/2/eNOS s1177/NO/DCC feed-forward mechanism.

Source

Division of Molecular Medicine, Cardiovascular Research Laboratories, Department of Anesthesiology, David Geffen School of Medicine at University of California Los Angeles, 650 Charles E. Young Drive, Los Angeles, CA 90095, USA.

Abstract

We have recently shown that a novel endothelial mitogen netrin-1 potently stimulates nitric oxide (NO()) production via a DCC-ERK1/2 dependent mechanism. In view of the well-established cardioprotective role of NO(), the present study investigated whether netrin-1 is cardioprotective via NO(*) signaling in the heart. Netrin-1 receptor DCC was abundantly expressed in the C57BL/6J mouse hearts. Perfusion of heart with netrin-1 (100 ng/mL) using a Langendorff system significantly increased NO(*) production. Under ischemia/reperfusion (I/R), netrin-1 induced a substantial reduction in infarct size (21.8+/-4.9% from 42.5+/-3.6% in the controls), which was accompanied by an augmented production of NO(*). Pre-perfusion with DCC-antibody, U0126 (MEK1/2 inhibitor), L-NAME or PTIO (NO(*) scavenger) attenuated protective effects of netrin-1 on infarct size and NO(*) production, indicating upstream roles of DCC and ERK1/2 in NO(*) production, as well as an essential role of NO(*) in cardioprotection. Netrin-1 induced reduction in infarct size was significantly attenuated in DCC+/- mice, confirming an intermediate role of DCC. In additional experiments we found netrin-1 increased ERK1/2 and eNOS(s1177) phosphorylation, and DCC protein expression, which was diminished by I/R. Furthermore, netrin-1-induced DCC upregulation was NO(*) and ERK1/2-dependent, implicating a feed-forward mechanism. DAF-AM staining revealed enhanced NO(*) production in both cardiac endothelial cells (ECs) and myocytes. In primarily isolated cardiomyocytes, netrin-1 also increased NO(*) production, DCC abundance and ERK1/2 phosphorylation. Of note, cardiac apoptosis was significantly attenuated by netrin-1, which was reversed by DCC-antibody, U0126, L-NAME or PTIO. In summary, our data clearly demonstrate that netrin-1 potently protects the heart from I/R injury by stimulating NO(*) production from cardiac ECs and myocytes. This potent effect is mediated by a DCC/ERK1/2/eNOS(s1177)/NO(*)/DCC feed-forward mechanism in both cell types.