Retinoic Acid Signaling and Heart Development

The heart is the first organ to function and is essential for the circulation of nutrients and oxygen in a rapidly growing mammalian embryo. Normal cardiac morphogenesis is thus indispensable for embryonic survival. Establishment of anterio-posterior (AP) polarity is one of the earliest decisions in cardiogenesis and plays an important role in the coupling between heart and blood vessels. Retinoic acid (RA) signaling is involved in this process. Mechanistically, a critical action of RA lies in its capacity to regulate the differentiation of cardiac embryonic stem/progenitor cells populations, typically by restricting domains of growth factor signaling and regulating Hox gene expression. In the fetal heart RA regulates myocardial growth through defined growth factor and transcriptional pathways. Another important issue in human health is understanding how sufficient nutritional levels of vitamin A intake offset congenital heart diseases (CHD).