title: "Triplet" polycistronic vectors encoding Gata4, Mef2c, and Tbx5 enhances postinfarct ventricular functional improvement compared with singlet vectors.
abstract: OBJECTIVE
  The in situ reprogramming of cardiac fibroblasts into induced cardiomyocytes by the administration of gene transfer vectors encoding Gata4 (G), Mef2c (M), and Tbx5 (T) has been shown to improve ventricular function in myocardial infarction models. The efficacy of this strategy could, however, be limited by the need for fibroblast targets to be infected 3 times--once by each of the 3 transgene vectors. We hypothesized that a polycistronic "triplet" vector encoding all 3 transgenes would enhance postinfarct ventricular function compared with use of "singlet" vectors.
  
  
  METHODS
  After validation of the polycistronic vector expression in vitro, adult male Fischer 344 rats (n=6) underwent coronary ligation with or without intramyocardial administration of an adenovirus encoding all 3 major vascular endothelial growth factor (VEGF) isoforms (AdVEGF-All6A positive), followed 3 weeks later by the administration to AdVEGF-All6A-positive treated rats of singlet lentivirus encoding G, M, or T (1×10(5) transducing units each) or the same total dose of a GMT "triplet" lentivirus vector.
  
  
  RESULTS
  Western blots demonstrated that triplet and singlet vectors yielded equivalent GMT transgene expression, and fluorescence activated cell sorting demonstrated that triplet vectors were nearly twice as potent as singlet vectors in generating induced cardiomyocytes from cardiac fibroblasts. Echocardiography demonstrated that GMT triplet vectors were more effective than the 3 combined singlet vectors in enhancing ventricular function from postinfarct baselines (triplet, 37%±10%; singlet, 13%±7%; negative control, 9%±5%; P<.05).
  
  
  CONCLUSIONS
  These data have confirmed that the in situ administration of G, M, and T induces postinfarct ventricular functional improvement and that GMT polycistronic vectors enhance the efficacy of this strategy.
authors.affiliation: Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Tex.
authors.forename: Megumi
authors.initials: M
authors.lastname: Mathison
authors.affiliation: Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Tex.
authors.forename: Vivek P
authors.initials: VP
authors.lastname: Singh
authors.affiliation: Department of Surgery, Stony Brook University Medical Center, Stony Brook, NY.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Gersch
authors.affiliation: Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Tex.
authors.forename: Maricela O
authors.initials: MO
authors.lastname: Ramirez
authors.affiliation: Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Tex.
authors.forename: Austin
authors.initials: A
authors.lastname: Cooney
authors.affiliation: Department of Genetic Medicine, Weill Cornell Medical College, New York, NY.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Kaminsky
authors.affiliation: Department of Genetic Medicine, Weill Cornell Medical College, New York, NY.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Chiuchiolo
authors.affiliation: Department of Surgery, Stony Brook University Medical Center, Stony Brook, NY.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Nasser
authors.affiliation: Department of Pathology, Stony Brook University Medical Center, Stony Brook, NY.
authors.forename: Jianchang
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Genetic Medicine, Weill Cornell Medical College, New York, NY.
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Crystal
authors.affiliation: Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Tex; Department of Cardiovascular Surgery, Texas Heart Institute, Houston, Tex. Electronic address: todd.rosengart@bcm.edu.
authors.forename: Todd K
authors.initials: TK
authors.lastname: Rosengart
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics* / Q000502:physiology; D005347:Fibroblasts / Q000473:pathology; D050991:GATA4 Transcription Factor / Q000235:genetics* / Q000502:physiology; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D064326:MEF2 Transcription Factors / Q000235:genetics / Q000502:physiology; D008297:Male; D023421:Models, Animal; D009203:Myocardial Infarction / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000473:pathology* / Q000502:physiology; D018006:Myogenic Regulatory Factors / Q000235:genetics* / Q000502:physiology; D051381:Rats; D011916:Rats, Inbred F344; D020825:T-Box Domain Proteins / Q000235:genetics* / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
chemical_list: D050991:GATA4 Transcription Factor; D064326:MEF2 Transcription Factors; C578042:MEF2C protein, rat; D018006:Myogenic Regulatory Factors; D020825:T-Box Domain Proteins; D042461:Vascular Endothelial Growth Factor A