Adenoviral delivery of E2F-1 directs cell cycle reentry and p53-independent apoptosis in postmitotic adult myocardium in vivo.
Irreversible exit from the cell cycle precludes the ability of cardiac muscle cells to increase cell number after infarction. Using adenoviral E1A, we previously demonstrated dual pocket protein- and p300-dependent pathways in neonatal rat cardiac myocytes, and have proven that E2F-1, which occupies the Rb pocket, suffices for these actions of E1A. By contrast, the susceptibility of adult ventricular cells to viral delivery of exogenous cell cycle regulators has not been tested, in vitro or in vivo. In cultured adult ventricular myocytes, adenoviral gene transfer of E2F-1 induced expression of proliferating cell nuclear antigen, cyclin-dependent protein kinase 4, cell division cycle 2 kinase, DNA synthesis, and apoptosis. In vivo, adenoviral delivery of E2F-1 by direct injection into myocardium induced DNA synthesis, shown by 5'-bromodeoxyuridine incorporation, and accumulation in G2/M, by image analysis of Feulgen-stained nuclei. In p53(-)/- mice, the prevalence of G1 exit was more than twofold greater; however, E2F-1 evoked apoptosis and rapid mortality comparably in both backgrounds. Thus, the differential effects of E2F-1 on G1 exit in wild-type versus p53-deficient mice illustrate the combinatorial power of viral gene delivery to genetically defined recipients: E2F-1 can override the G1/S checkpoint in postmitotic ventricular myocytes in vitro and in vivo, but leads to apoptosis even in p53(-)/- mice.
Agah
R
R
Molecular Cardiology Unit, Baylor College of Medicine, Houston, Texas 77030, USA.
Kirshenbaum
L A
LA
Abdellatif
M
M
Truong
L D
LD
Chakraborty
S
S
Michael
L H
LH
Schneider
M D
MD
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D017209:Apoptosis; D002352:Carrier Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D017353:Gene Deletion; D005822:Genetic Vectors; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008938:Mitosis; D009206:Myocardium / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D056465:Retinoblastoma-Binding Protein 1; D015398:Signal Transduction; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000008:administration & dosage / Q000235:genetics* / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000502:physiology
C533431:Arid4a protein, mouse; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; C493754:E2f1 protein, mouse; C493755:E2f1 protein, rat; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D004247:DNA