title: Endogenous endothelin-1 is required for cardiomyocyte survival in vivo.
abstract: BACKGROUND
  Endothelin-1 (ET-1) has potent vasoconstrictor and hypertrophic actions. Pharmacological antagonists of endothelin receptors attenuate cardiac hypertrophy, have been approved for treatment of pulmonary hypertension, and are under investigation for treatment of heart failure. To investigate the role of ET-1 in the heart, we created mice with cardiomyocyte deletion of ET-1.
  
  
  RESULTS
  Mice with cardiomyocyte-specific deletion of ET-1 are phenotypically normal when young. Remarkably, as the mice age or when young animals are subjected to aortic banding, they develop an unexpected phenotype of progressive systolic dysfunction and cardiac dilation. Echocardiography, necropsy, histology, and molecular phenotype confirm a dilated cardiomyopathy. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling analysis reveals greater abundance of apoptotic nuclei in the ET-1-deficient hearts. Transcriptional and Western analyses suggest enhanced tumor necrosis factor (TNF)-mediated apoptosis with increases in caspase-8 activity. These ET-1-deficient hearts also have diminished nuclear factor (NF)-kappaB activity, resulting in diminution of downstream inhibitors of TNF signaling.
  
  
  CONCLUSIONS
  Local ET-1 gene expression is necessary to maintain normal cardiac function and cardiomyocyte survival in mice with both age and hemodynamic stress. This cardiac-protective effect is mediated by paracrine ET-1 modulation of TNF-related apoptosis, in part through upregulation of NF-kappaB signaling.
authors.affiliation: Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Xiao-Song
authors.initials: XS
authors.lastname: Zhao
authors.forename: Wentong
authors.initials: W
authors.lastname: Pan
authors.forename: Raffi
authors.initials: R
authors.lastname: Bekeredjian
authors.forename: Ralph V
authors.initials: RV
authors.lastname: Shohet
mesh_terms: D000375:Aging; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001483:Base Sequence; D016384:Consensus Sequence; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism; D019332:Endothelin-1 / Q000172:deficiency / Q000235:genetics* / Q000502:physiology*; D017353:Gene Deletion; D006331:Heart Diseases / Q000235:genetics / Q000503:physiopathology; D006439:Hemodynamics / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D032342:Muscle Cells / Q000166:cytology*; D009206:Myocardium / Q000166:cytology* / Q000201:enzymology; D016328:NF-kappa B / Q000378:metabolism
chemical_list: D019332:Endothelin-1; D016328:NF-kappa B; D004253:DNA Nucleotidylexotransferase