title: Notch1 signaling stimulates proliferation of immature cardiomyocytes.
abstract: The identification of the molecular mechanisms controlling cardiomyocyte proliferation during the embryonic, fetal, and early neonatal life appears of paramount interest in regard to exploiting this information to promote cardiac regeneration. Here, we show that the proliferative potential of neonatal rat cardiomyocytes is powerfully stimulated by the sustained activation of the Notch pathway. We found that Notch1 is expressed in proliferating ventricular immature cardiac myocytes (ICMs) both in vitro and in vivo, and that the number of Notch1-positive cells in the heart declines with age. Notch1 expression in ICMs paralleled the expression of its Jagged1 ligand on non-myocyte supporting cells. The inhibition of Notch signaling in ICMs blocked their proliferation and induced apoptosis; in contrast, its activation by Jagged1 or by the constitutive expression of its activated form using an adeno-associated virus markedly stimulated proliferative signaling and promoted ICM expansion. Maintenance or reactivation of Notch signaling in cardiac myocytes might represent an interesting target for innovative regenerative therapy.
authors.affiliation: Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Collesi
authors.forename: Lorena
authors.initials: L
authors.lastname: Zentilin
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Sinagra
authors.forename: Mauro
authors.initials: M
authors.lastname: Giacca
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008954:Models, Biological; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D041681:NIH 3T3 Cells; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D051881:Receptor, Notch1 / Q000037:antagonists & inhibitors / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D000072056:Transcription Factor HES-1; D014162:Transfection
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D018797:Cell Cycle Proteins; D017077:Culture Media, Conditioned; D004151:Dipeptides; D018398:Homeodomain Proteins; D011480:Protease Inhibitors; D051881:Receptor, Notch1; D000072056:Transcription Factor HES-1; C489735:Hes1 protein, rat; C419410:N-(N-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl ester; C497763:Notch1 protein, rat