title: Induction of cardiomyocyte-like cells in infarct hearts by gene transfer of Gata4, Mef2c, and Tbx5.
abstract: BACKGROUND
  After myocardial infarction (MI), massive cell death in the myocardium initiates fibrosis and scar formation, leading to heart failure. We recently found that a combination of 3 cardiac transcription factors, Gata4, Mef2c, and Tbx5 (GMT), reprograms fibroblasts directly into functional cardiomyocytes in vitro.
  
  
  OBJECTIVE
  To investigate whether viral gene transfer of GMT into infarcted hearts induces cardiomyocyte generation.
  
  
  RESULTS
  Coronary artery ligation was used to generate MI in the mouse. In vitro transduction of GMT retrovirus converted cardiac fibroblasts from the infarct region into cardiomyocyte-like cells with cardiac-specific gene expression and sarcomeric structures. Injection of the green fluorescent protein (GFP) retrovirus into mouse hearts, immediately after MI, infected only proliferating noncardiomyocytes, mainly fibroblasts, in the infarct region. The GFP expression diminished after 2 weeks in immunocompetent mice but remained stable for 3 months in immunosuppressed mice, in which cardiac induction did not occur. In contrast, injection of GMT retrovirus into α-myosin heavy chain (αMHC)-GFP transgenic mouse hearts induced the expression of αMHC-GFP, a marker of cardiomyocytes, in 3% of virus-infected cells after 1 week. A pooled GMT injection into the immunosuppressed mouse hearts induced cardiac marker expression in retrovirus-infected cells within 2 weeks, although few cells showed striated muscle structures. To transduce GMT efficiently in vivo, we generated a polycistronic retrovirus expressing GMT separated by 2A "self-cleaving" peptides (3F2A). The 3F2A-induced cardiomyocyte-like cells in fibrotic tissue expressed sarcomeric α-actinin and cardiac troponin T and had clear cross striations. Quantitative RT-PCR also demonstrated that FACS-sorted 3F2A-transduced cells expressed cardiac-specific genes.
  
  
  CONCLUSIONS
  GMT gene transfer induced cardiomyocyte-like cells in infarcted hearts.
authors.affiliation: Department of Clinical and Molecular Cardiovascular Research, Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Inagawa
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamakawa
authors.forename: Naoto
authors.initials: N
authors.lastname: Muraoka
authors.forename: Taketaro
authors.initials: T
authors.lastname: Sadahiro
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Umei
authors.forename: Rie
authors.initials: R
authors.lastname: Wada
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Katsumata
authors.forename: Ruri
authors.initials: R
authors.lastname: Kaneda
authors.forename: Koji
authors.initials: K
authors.lastname: Nakade
authors.forename: Chitose
authors.initials: C
authors.lastname: Kurihara
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Obata
authors.forename: Koichi
authors.initials: K
authors.lastname: Miyake
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukuda
authors.forename: Masaki
authors.initials: M
authors.lastname: Ieda
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics* / Q000502:physiology; D005347:Fibroblasts / Q000473:pathology; D050991:GATA4 Transcription Factor / Q000235:genetics* / Q000502:physiology; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics; D064326:MEF2 Transcription Factors; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008819:Mice, Nude; D008822:Mice, Transgenic; D023421:Models, Animal; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000473:pathology* / Q000502:physiology; D018006:Myogenic Regulatory Factors / Q000235:genetics* / Q000502:physiology; D012038:Regeneration / Q000235:genetics / Q000502:physiology; D012190:Retroviridae / Q000235:genetics; D020825:T-Box Domain Proteins / Q000235:genetics* / Q000502:physiology
chemical_list: D050991:GATA4 Transcription Factor; C484171:Gata4 protein, mouse; D064326:MEF2 Transcription Factors; C578041:Mef2c protein, mouse; D018006:Myogenic Regulatory Factors; D020825:T-Box Domain Proteins; C103172:T-box transcription factor 5; D049452:Green Fluorescent Proteins