title: Endothelin-1 promotes cardiomyocyte terminal differentiation in the developing heart via heightened DNA methylation.
abstract: OBJECTIVE
  Hypoxia is a major stress on fetal development and leads to induction of endothelin-1 (ET-1) expression. We tested the hypothesis that ET-1 stimulates the terminal differentiation of cardiomyocytes from mononucleate to binucleate in the developing heart.
  
  
  RESULTS
  Hypoxia (10.5% O2) treatment of pregnant rats from day 15 to day 21 resulted in a significant increase in prepro-ET-1 mRNA expression in fetal hearts. ET-1 ex vivo treatment of fetal rat cardiomyocytes increased percent binucleate cells and decreased Ki-67 expression, a marker for proliferation, under both control and hypoxic conditions. Hypoxia alone decreased Ki-67 expression and in conjunction with ET-1 treatment decreased cardiomyocyte size. PD145065, a non-selective ET-receptor antagonist, blocked the changes in binucleation and proliferation caused by ET-1. DNA methylation in fetal cardiomyocytes was significantly increased with ET-1 treatment, which was blocked by 5-aza-2'-deoxycytidine, a DNA methylation inhibitor. In addition, 5-aza-2'-deoxycytidine treatment abrogated the increase in binucleation and decrease in proliferation induced by ET-1.
  
  
  CONCLUSIONS
  Hypoxic stress and synthesis of ET-1 increases DNA methylation and promotes terminal differentiation of cardiomyocytes in the developing heart. This premature exit of the cell cycle may lead to a reduced cardiomyocyte endowment in the heart and have a negative impact on cardiac function.
authors.affiliation: 1. Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California 92350.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Paradis
authors.affiliation: 1. Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California 92350.
authors.forename: Daliao
authors.initials: D
authors.lastname: Xiao
authors.affiliation: 1. Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California 92350 ; 2. Department of Obstetrics and Gynecology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Zhou
authors.affiliation: 1. Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California 92350.
authors.forename: Lubo
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000818:Animals; D019175:DNA Methylation / Q000235:genetics / Q000502:physiology*; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology; D007150:Immunohistochemistry; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism*; D011247:Pregnancy; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D019332:Endothelin-1
keywords: Endothelin-1; Epigenetic; Fetal development; Heart; Hypoxia