title: RNAi-Mediated Down-Regulation of CD47 Protects against Ischemia/Reperfusion-Induced Myocardial Damage via Activation of eNOS in a Rat Model.
abstract: OBJECTIVE
  Oxidative stress is strongly implicated in the pathogenesis of myocardial damage caused by ischemia reperfusion (I/R). Previous studies have confirmed that cardiac CD47 drives left ventricular heart failure. However, the role for CD47 in myocardial I/R injury (MIRI) has not previously been proposed. This study was designed to investigate whether down-regulation of CD47 using RNA interference (RNAi) technology can relieve inhibition of nitric oxide signaling and attenuate myocardial damage in a rat model of I/R.
  
  
  METHODS
  Male Sprague-Dawley rats (n = 40) were randomly allocated to four groups and pre-treated either with saline (Sham and I/R groups), or adenovirus expressing either control (Ad-EGFP-N) or CD47-targeting (Ad-EGFP-CD47) RNAi. After four days, the rat MIRI model was established by occluding the left anterior descending coronary artery for 30 min, followed by reperfusion for 3 h. Heart tissue was harvested and assessed by immunohistochemistry, western blot, and quantitative RT-PCR. Outcome measures included infarct size, myocardial enzyme (creatine kinase, creatine kinase-MB, and lactate dehydrogenase) levels in serum, markers of oxidative stress, and morphological changes to the myocardium.
  
  
  RESULTS
  Delivery of Ad-EGFP-CD47 RNAi into the myocardium remarkably decreased CD47 expression levels. Down-regulation of CD47 was significantly associated with reduced infarct size and serum levels of myocardial enzymes, increased activity of endothelial nitric oxide synthase, increased levels of nitric oxide, and decreased levels of oxidative stress.
  
  
  CONCLUSIONS
  These data indicate that down-regulation of CD47 exerts a protective effect against MIRI, which may be attributable to attenuation of oxidative stress via activation of the eNOS/NO signaling pathway.
authors.affiliation: Department of Cardiology, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang, China.
authors.forename: Hui-Bo
authors.initials: HB
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Jia-Wang
authors.initials: JW
authors.lastname: Ding
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: Chen
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.forename: Xiao-Wen
authors.initials: XW
authors.lastname: Liu
authors.forename: Chao-Jun
authors.initials: CJ
authors.lastname: Yang
authors.forename: Zhi-Xin
authors.initials: ZX
authors.lastname: Fan
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
mesh_terms: D000256:Adenoviridae / Q000378:metabolism; D000818:Animals; D051928:CD47 Antigen / Q000378:metabolism*; D004195:Disease Models, Animal; D015536:Down-Regulation; D004789:Enzyme Activation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000201:enzymology* / Q000473:pathology*; D009206:Myocardium / Q000201:enzymology / Q000473:pathology*; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D018384:Oxidative Stress; D034622:RNA Interference; D017207:Rats, Sprague-Dawley; D014162:Transfection; D015854:Up-Regulation
chemical_list: D051928:CD47 Antigen; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III