endothelin-1 and Cardiovascular-Abnormalities

Topics: Animals; Branchial Region; Cardiovascular Abnormalities; Cardiovascular System; Craniofacial Abnormalities; Endothelin-1; Hirschsprung Disease; Humans; Mice; Mice, Knockout; Neural Crest; Phenotype; Receptor, Endothelin A; Signal Transduction

Ligating the right lateral vitelline vein of chicken embryos (venous clip) results in cardiovascular malformations. These abnormalities are similar to malformations observed in knockout mice studies of components of the endothelin-1 (ET-1)/endothelin-converting enzyme-1/endothelin-A receptor pathway. In previous studies we demonstrated that cardiac ET-1 expression is decreased 3 h after clipping, and ventricular diastolic filling is disturbed after 2 days. Therefore, we hypothesise that ET-1-related processes are involved in the development of functional and morphological cardiovascular defects after venous clip.. In this study, ET-1 and endothelin receptor antagonists (BQ-123, BQ-788 and PD145065) were infused into the HH18 embryonic circulation. Immediate haemodynamic effects on the embryonic heart and extra-embryonic vitelline veins were examined by Doppler and micro-particle image velocimetry. Ventricular diastolic filling characteristics were studied at HH24, followed by cardiovascular morphologic investigation (HH35).. ET-1 and its receptor antagonists induced haemodynamic effects at HH18. At HH24, a reduced diastolic ventricular passive filling component was demonstrated, which was compensated by an increased active filling component. Thinner ventricular myocardium was shown in 42% of experimental embryos.. We conclude that cardiovascular malformations after venous clipping arise from a combination of haemodynamic changes and altered gene expression patterns and levels, including those of the endothelin pathway.

Topics: Animals; Aspartic Acid Endopeptidases; Blood Flow Velocity; Cardiac Output; Cardiovascular Abnormalities; Cells, Cultured; Chick Embryo; Echocardiography; Endothelin Receptor Antagonists; Endothelin-1; Endothelin-Converting Enzymes; Gene Expression Regulation, Developmental; Heart; Heart Rate; Hemodynamics; Laser-Doppler Flowmetry; Ligation; Metalloendopeptidases; Myocardium; Oligopeptides; Peptides, Cyclic; Piperidines; Receptors, Endothelin; RNA, Messenger; Signal Transduction; Time Factors; Veins; Ventricular Function; Yolk Sac

Hypoxia-inducible factors (HIFs) are crucial for oxygen homeostasis during both embryonic development and postnatal life. Here we show that a novel HIF family basic helix-loop-helix (bHLH) PAS (Per-Arnt-Sim) protein, which is expressed predominantly during embryonic and neonatal stages and thereby designated NEPAS (neonatal and embryonic PAS), acts as a negative regulator of HIF-mediated gene expression. NEPAS mRNA is derived from the HIF-3alpha gene by alternative splicing, replacing the first exon of HIF-3alpha with that of inhibitory PAS. NEPAS can dimerize with Arnt and exhibits only low levels of transcriptional activity, similar to that of HIF-3alpha. NEPAS suppressed reporter gene expression driven by HIF-1alpha and HIF-2alpha. By generating mice with a targeted disruption of the NEPAS/HIF-3alpha locus, we found that homozygous mutant mice (NEPAS/HIF-3alpha(-)(/)(-)) were viable but displayed enlargement of the right ventricle and impaired lung remodeling. The expression of endothelin 1 and platelet-derived growth factor beta was increased in the lung endothelial cells of NEPAS/HIF-3alpha-null mice. These results demonstrate a novel regulatory mechanism in which the activities of HIF-1alpha and HIF-2alpha are negatively regulated by NEPAS in endothelial cells, which is pertinent to lung and heart development during the embryonic and neonatal stages.

Topics: Alternative Splicing; Amino Acid Sequence; Animals; Apoptosis Regulatory Proteins; Basic Helix-Loop-Helix Transcription Factors; Cardiovascular Abnormalities; Cell Separation; Endothelial Cells; Endothelin-1; Gene Expression Regulation, Developmental; Gene Targeting; Heart; Lung; Mice; Mice, Knockout; Molecular Sequence Data; Phenotype; Repressor Proteins; RNA, Messenger; Transcription Factors; Transcription, Genetic