title: Netrin-1 improves post-injury cardiac function in vivo via DCC/NO-dependent preservation of mitochondrial integrity, while attenuating autophagy.
abstract: Reperfusion injury of the heart is a severe complication of angioplasty treatment of acute myocardial ischemia, for which no therapeutics are currently available. The present study aimed to identify whether and how a novel protein, netrin-1, induces cardioprotection in vivo during ischemia/reperfusion (I/R) injury. Wild type (WT) C57BL6/J mice were subjected to a 30 min coronary occlusion followed by a 24h reperfusion with vehicle (normal saline), netrin-1, UO126 (MEK1/2 inhibitor), PTIO (nitric oxide/NO scavenger), netrin-1/UO126 or netrin-1/PTIO intraventricularly. Some were injected of netrin-1 via tail vein. Netrin-1 at 5μg/kg induced a substantial reduction in infarct size (19.7 ± 5.0% from 41.3 ± 1.8% in the controls), and markedly improved cardiac function as measured by ejection fraction and fractional shortening from echocardiography. Experiments with mice deficient in netrin-1 receptor DCC (deleted in colorectal cancer, DCC+/-), or reperfusion with netrin-1/UO126 or netrin-1/PTIO, attenuated the protective effects of netrin-1, implicating intermediate roles of DCC, ERK1/2 and NO. Netrin-1 induced phosphorylation of ERK1/2 and eNOS was abolished in DCC+/-mice. Electron spin resonance (ESR) determination of NO production from isolated left ventricles demonstrated that netrin-1 improves NO bioavailability, which was attenuated by UO126 or in DCC+/-mice, suggesting upstream roles of DCC and ERK1/2 in NO production. Netrin-1 further reduced mitochondrial swelling and mitochondrial superoxide production, which was absent when co-treated with PTIO or UO126, or in DCC+/-mice, indicating critical roles of DCC, ERK1/2 and NO in preserving mitochondrial integrity. In a permanent coronary ligation model of myocardial infarction (MI) to assess post-MI remodeling, netrin-1 abolished the marked increase in autophagy. In summary, our data demonstrate robust cardioprotective effect of netrin-1 in vivo, as shown by reduced infarct size and improved cardiac function. Mechanistically, this protection is mediated by netrin-1 receptor DCC, and NO dependent preservation of mitochondria. This work clearly establishes a therapeutic potential of netrin-1 for acute treatment of MI, perhaps also for chronic post-MI remodeling. This article is part of a Special Issue entitled: Autophagy and protein quality control in cardiometabolic diseases.
authors.affiliation: Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine at University of California Los Angeles, 650 Charles E. Young Drive, Los Angeles, CA 90095, USA.
authors.forename: Jalaleddinne Omar
authors.initials: JO
authors.lastname: Bouhidel
authors.affiliation: Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine at University of California Los Angeles, 650 Charles E. Young Drive, Los Angeles, CA 90095, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine at University of California Los Angeles, 650 Charles E. Young Drive, Los Angeles, CA 90095, USA.
authors.forename: Kin Lung
authors.initials: KL
authors.lastname: Siu
authors.affiliation: Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine at University of California Los Angeles, 650 Charles E. Young Drive, Los Angeles, CA 90095, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine at University of California Los Angeles, 650 Charles E. Young Drive, Los Angeles, CA 90095, USA.
authors.forename: Ji Youn
authors.initials: JY
authors.lastname: Youn
authors.affiliation: Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine at University of California Los Angeles, 650 Charles E. Young Drive, Los Angeles, CA 90095, USA. Electronic address: hcai@mednet.ucla.edu.
authors.forename: Hua
authors.initials: H
authors.lastname: Cai
mesh_terms: D000818:Animals; D001343:Autophagy; D002316:Cardiotonic Agents / Q000378:metabolism; D000075389:DCC Receptor; D015536:Down-Regulation; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006334:Heart Function Tests; D008297:Male; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000378:metabolism*; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism; D009414:Nerve Growth Factors / Q000378:metabolism*; D000075388:Netrin-1; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D066253:Vascular Remodeling
chemical_list: D002316:Cardiotonic Agents; D000075389:DCC Receptor; C501910:Dcc protein, mouse; D009414:Nerve Growth Factors; C000617353:Ntn1 protein, mouse; D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins; D013481:Superoxides; D000075388:Netrin-1; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C422943:Nox4 protein, mouse; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: Autophagy; Ischemia reperfusion (I/R) injury; Myocardial infarction (MI); NADPH oxidase isoforms 4 (NOX4); Netrin-1; Nitric oxide (NO)