The proposed work is a continuation of a long term goal to elucidate the physiological function of vitamin A in embryonic development. Our working hypothesis is that critical early developmental events involving the specification of the cardiovascular and central nervous systems are regulated by vitamin A within a common narrow developmental window. The main focus of the present research is on the formation of the cardiovascular system.
The specific aims are: 1. Determine the spatiotemporal sequence of vitamin A-regulated heart forming and asymmetry determining morphological events. Dysregulation of morphological and cellular events caused by the lack of vitamin A during early embryogenesis will be accurately described using multiple molecular markers. These studies are essential for the subsequent analysis of molecular events. 2. Examine regulation of expression of the cardiac-specific genes GATA-4/5/6 by vitamin A. Effects of retinoids on the expression of GATAs and GATA-4 target genes will be analyzed in retinoid-deficient embryos. The involvement of retinoid receptors in GATA-4 regulation will be studied using receptor-selective ligands and oligonucleotides directed against receptors and GATAs. 3. Identify retinoid-dependent cardiac asymmetry regulating genes. Effect of vitamin A deficiency on the expression of cardiac asymmetry-linked genes will be determined, with focus on SnR-1 which is severely downregulated in absence of vitamin A. SnR-1 regulation by retinoids will be studied with retinoid receptor specific ligands and antisense oligonucleotides. The studies will utilize our novel vitamin A-deficient quail embryo model. Gene expression will be studied by whole-mount in situ hybridization. Cell and tissue diversification will be identified with molecular markers. The proposed studies offer an unique opportunity to learn about the critical role of vitamin A in cardiovascular development so as to apply this knowledge to understanding the origin of congenital heart defects that may arise as a result of marginal vitamin A nutrition during pregnancy.
|Lloret-Vilaspasa, Ferran; Jansen, Hans J; de Roos, Koen et al. (2010) Retinoid signalling is required for information transfer from mesoderm to neuroectoderm during gastrulation. Int J Dev Biol 54:599-608|
|Ghatpande, Satish K; Zhou, Hui-Ren; Cakstina, Inese et al. (2010) Transforming growth factor beta2 is negatively regulated by endogenous retinoic acid during early heart morphogenesis. Dev Growth Differ 52:433-55|
|Romeih, Mahmoud; Cakstina, Inese; Zile, Maija H (2009) Retinoic acid is a negative physiological regulator of N-cadherin during early avian heart morphogenesis. Dev Growth Differ 51:753-67|
|Garic-Stankovic, Ana; Hernandez, Marcos; Flentke, George R et al. (2008) A ryanodine receptor-dependent Ca(i)(2+) asymmetry at Hensen's node mediates avian lateral identity. Development 135:3271-80|
|Ghatpande, Satish; Brand, Thomas; Zile, Maija et al. (2006) Bmp2 and Gata4 function additively to rescue heart tube development in the absence of retinoids. Dev Dyn 235:2030-9|
|Kil, Sung-Hee; Streit, Andrea; Brown, Stephen T et al. (2005) Distinct roles for hindbrain and paraxial mesoderm in the induction and patterning of the inner ear revealed by a study of vitamin-A-deficient quail. Dev Biol 285:252-71|
|Zile, Maija H (2004) Vitamin a requirement for early cardiovascular morphogenesis specification in the vertebrate embryo: insights from the avian embryo. Exp Biol Med (Maywood) 229:598-606|
|Romeih, Mahmoud; Cui, Jian; Michaille, Jean-Jacques et al. (2003) Function of RARgamma and RARalpha2 at the initiation of retinoid signaling is essential for avian embryo survival and for distinct events in cardiac morphogenesis. Dev Dyn 228:697-708|
|Halilagic, Aida; Zile, Maija H; Studer, Michele (2003) A novel role for retinoids in patterning the avian forebrain during presomite stages. Development 130:2039-50|
|Zile, M H; Kostetskii, I; Yuan, S et al. (2000) Retinoid signaling is required to complete the vertebrate cardiac left/right asymmetry pathway. Dev Biol 223:323-38|