title: Molecular strategy to reduce in vivo collagen barrier promotes entry of NCX1 positive inducible pluripotent stem cells (iPSC(NCX¹⁺)) into ischemic (or injured) myocardium.
abstract: OBJECTIVE
  The purpose of this study was to assess the effect of collagen composition on engraftment of progenitor cells within infarcted myocardium.
  
  
  BACKGROUND
  We previously reported that intramyocardial penetration of stem/progenitor cells in epicardial patches was enhanced when collagen was reduced in hearts overexpressing adenylyl cyclase-6 (AC6). In this study we hypothesized an alternative strategy wherein overexpression of microRNA-29b (miR-29b), inhibiting mRNAs that encode cardiac fibroblast proteins involved in fibrosis, would similarly facilitate progenitor cell migration into infarcted rat myocardium.
  
  
  METHODS
  In vitro: A tri-cell patch (Tri-P) consisting of cardiac sodium-calcium exchanger-1 (NCX1) positive iPSC (iPSC(NCX1+)), endothelial cells (EC), and mouse embryonic fibroblasts (MEF) was created, co-cultured, and seeded on isolated peritoneum. The expression of fibrosis-related genes was analyzed in cardiac fibroblasts (CFb) by qPCR and Western blot. In vivo: Nude rat hearts were administered mimic miRNA-29b (miR-29b), miRNA-29b inhibitor (Anti-29b), or negative mimic (Ctrl) before creation of an ischemically induced regional myocardial infarction (MI). The Tri-P was placed over the infarcted region 7 days later. Angiomyogenesis was analyzed by micro-CT imaging and immunofluorescent staining. Echocardiography was performed weekly.
  
  
  RESULTS
  The number of green fluorescent protein positive (GFP(+)) cells, capillary density, and heart function were significantly increased in hearts overexpressing miR-29b as compared with Ctrl and Anti-29b groups. Conversely, down-regulation of miR-29b with anti-29b in vitro and in vivo induced interstitial fibrosis and cardiac remodeling.
  
  
  CONCLUSIONS
  Overexpression of miR-29b significantly reduced scar formation after MI and facilitated iPSC(NCX1+) penetration from the cell patch into the infarcted area, resulting in restoration of heart function after MI.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Cincinnati Medical Center, Cincinnati, Ohio, United States of America.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Bo
authors.initials: B
authors.lastname: Dai
authors.forename: Zhili
authors.initials: Z
authors.lastname: Wen
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Millard
authors.forename: Xi-Yong
authors.initials: XY
authors.lastname: Yu
authors.forename: Kristin
authors.initials: K
authors.lastname: Luther
authors.forename: Meifeng
authors.initials: M
authors.lastname: Xu
authors.forename: Ting C
authors.initials: TC
authors.lastname: Zhao
authors.forename: Huang-Tian
authors.initials: HT
authors.lastname: Yang
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Qi
authors.forename: Kathleen
authors.initials: K
authors.lastname: Lasance
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ashraf
authors.forename: Yigang
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D002465:Cell Movement; D018920:Coculture Techniques; D003094:Collagen / Q000737:chemistry*; D004452:Echocardiography; D005347:Fibroblasts / Q000166:cytology; D005355:Fibrosis / Q000473:pathology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D057026:Induced Pluripotent Stem Cells / Q000166:cytology*; D016086:Lentivirus / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism; D009203:Myocardial Infarction / Q000473:pathology; D017202:Myocardial Ischemia / Q000473:pathology*; D009206:Myocardium / Q000378:metabolism*; D009389:Neovascularization, Pathologic; D051381:Rats; D011923:Rats, Nude; D019831:Sodium-Calcium Exchanger / Q000378:metabolism*; D014162:Transfection; D020257:Ventricular Remodeling / Q000502:physiology; D055114:X-Ray Microtomography
chemical_list: C526366:MIRN29 microRNA, rat; D035683:MicroRNAs; D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1; D049452:Green Fluorescent Proteins; D003094:Collagen