title: Necroptosis Induced by Ad-HGF Activates Endogenous C-Kit+ Cardiac Stem Cells and Promotes Cardiomyocyte Proliferation and Angiogenesis in the Infarcted Aged Heart.
abstract: OBJECTIVE
  The discovery of c-kit+ cardiac stem cells (CSCs) provided us with new therapeutic targets to repair the damaged heart. However, the precise mechanisms regulating CSC proliferation and differentiation in the aged heart remained elusive. Necroptosis, a type of regulated cell death, has recently been shown to occur following myocardial infarction (MI); however, its effect on c-kit+ CSCs remains unknown. We investigated the effects of hepatocyte growth factor (HGF) and necroptosis on the proliferation and differentiation of endogenous c-kit+ CSCs in aged rat hearts following MI.
  
  
  METHODS
  The c-kit+ CSCs and HGF/p-Met expression levels in neonatal, adult and aged rats were compared using immunofluorescence and Western blotting. Immediately after MI, adenovirus carrying the HGF gene (Ad-HGF) was injected into the left ventricular wall surrounding the infarct areas of the aged rat heart. The proliferation and differentiation of the endogenous c-kit+ CSCs were studied using immunofluorescence. The signalling pathways were analysed via Western blotting and ELISA.
  
  
  RESULTS
  HGF/p-Met expression levels and c-kit+ CSC abundance gradually decreased with age. Ad-HGF promoted c-kit+ CSC differentiation into precursor cells of cardiomyocyte, endothelial and smooth muscle cell lineages and enhanced cardiomyocyte proliferation and angiogenesis in aged rats; these effects were reversed by the inhibition of necroptosis. Ad-HGF administration induced necroptosis by increasing the expression of receptor interacting protein kinase (RIP) 1 and receptor interacting protein kinase (RIP) 3 proteins in the infarcted heart. Moreover, Ad-HGF-induced necroptosis increased high-mobility group box 1 protein (HMGB1) levels and enhanced the abundance of c-kit+ cells in the bone marrow, which may partly account for the beneficial effect of necroptosis on the c-kit+ CSCs.
  
  
  CONCLUSIONS
  Ad-HGF-induced necroptosis facilitated aged heart repair after MI by promoting c-kit+ CSC proliferation and differentiation. These findings may lead to the development of new methods for the treatment of ischaemic heart disease in aged populations.
authors.affiliation: Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Jiabao
authors.initials: J
authors.lastname: Liu
authors.forename: Peng
authors.initials: P
authors.lastname: Wu
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Yunle
authors.initials: Y
authors.lastname: Wang
authors.forename: Yingqiang
authors.initials: Y
authors.lastname: Du
authors.forename: Weili
authors.initials: W
authors.lastname: Cheng
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Xu
authors.forename: Ningtian
authors.initials: N
authors.lastname: Zhou
authors.forename: Liansheng
authors.initials: L
authors.lastname: Wang
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000256:Adenoviridae / Q000378:metabolism; D000375:Aging; D000818:Animals; D017209:Apoptosis; D001853:Bone Marrow / Q000473:pathology; D002452:Cell Count; D049109:Cell Proliferation; D024243:HMGB1 Protein / Q000378:metabolism; D017228:Hepatocyte Growth Factor / Q000378:metabolism*; D008297:Male; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology*; D009206:Myocardium / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000473:pathology*; D009336:Necrosis; D018919:Neovascularization, Physiologic; D010766:Phosphorylation; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D012038:Regeneration; D013234:Stem Cells / Q000166:cytology*
chemical_list: D024243:HMGB1 Protein; D017228:Hepatocyte Growth Factor; D019009:Proto-Oncogene Proteins c-kit; D019859:Proto-Oncogene Proteins c-met