title: GATA-4 promotes myocardial transdifferentiation of mesenchymal stromal cells via up-regulating IGFBP-4.
abstract: OBJECTIVE
  GATA-4 is a cardiac transcription factor and plays an important role in cell lineage differentiation during development. We investigated whether overexpression of GATA-4 increases adult mesenchymal stromal cell (MSC) transdifferentiation into a cardiac phenotype in vitro.
  
  
  METHODS
  MSC were harvested from rat bone marrow (BM) and transduced with GATA-4 (MSC(GATA-4)) using a murine stem cell virus (pMSCV) retroviral expression system. Gene expression in MSC(GATA-4) was analyzed using quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. Native cardiomyocytes (CM) were isolated from ventricles of neonatal rats. Myocardial transdifferentiation of MSC was determined by immunostaining and electrophysiologic recording. The transdifferentiation rate was calculated directly from flow cytometery.
  
  
  RESULTS
  The expression of cardiac genes, including brain natriuretic peptide (BNP), Islet-1 and α-sarcomeric actinin (α-SA), was up-regulated in MSC(GATA-4) compared with control cells that were transfected with Green Fluorescent Protein (GFP) only (MSC(Null)). At the same time, insulin-like growth factor-binding protein (IGFBP)-4 was significantly up-regulated in MSC(GATA-4). A synchronous beating of MSC with native CM was detected and an action potential was recorded. Some GFP (+) cells were positive for α-SA staining after MSC were co-cultured with native CM for 7 days. The transdifferentiation rate was significantly higher in MSC(GATA-4). Functional studies indicated that the differentiation potential of MSC(GATA-4) was decreased by knockdown of IGFBP-4.
  
  
  CONCLUSIONS
  Overexpression of GATA-4 significantly increases MSC differentiation into a myocardial phenotype, which might be associated with the up-regulation of IGFBP-4.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Cincinnati Medical Center, Cincinnati, OH 45867, USA.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Li
authors.forename: Shi
authors.initials: S
authors.lastname: Zuo
authors.forename: Zeeshan
authors.initials: Z
authors.lastname: Pasha
authors.forename: Bin
authors.initials: B
authors.lastname: Yu
authors.forename: Zhisong
authors.initials: Z
authors.lastname: He
authors.forename: Yigang
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Yang
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ashraf
authors.forename: Meifeng
authors.initials: M
authors.lastname: Xu
mesh_terms: D053687:Adult Stem Cells / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D001853:Bone Marrow / Q000378:metabolism* / Q000473:pathology; D019070:Cell Lineage / Q000235:genetics; D054338:Cell Transdifferentiation / Q000235:genetics; D002478:Cells, Cultured; D018920:Coculture Techniques; D022062:Electrophysiologic Techniques, Cardiac; D050991:GATA4 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006352:Heart Ventricles / Q000473:pathology; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000235:genetics / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D032383:Myocytes, Cardiac / Q000473:pathology; D051381:Rats; D019076:Transgenes / Q000235:genetics; D015854:Up-Regulation
chemical_list: D050991:GATA4 Transcription Factor; D018974:Insulin-Like Growth Factor Binding Protein 4