Molecular mechanisms of cardiac development

Abstract

The heart is the first organ to develop in order to supply the ever-increasing metabolic demands of the growing embryo. The heart is a unique structure in the body as it is derived from four distinct pools of progenitors: The first heart field (cardiac crescent), the second heart field (SHF), the proepicardial organ and the cardiac neural crest. These progenitors differentiate into the different cell types that comprise the adult heart: Cardiomyocytes, endothelial cells, vascular smooth muscle cells, fibroblasts, and the conduction system. This complex program of differentiation is controlled by different molecular signaling pathways. A key component of the cardiac development program is the exquisitely coordinated expression of various genes in a spatially and temporally controlled fashion. Genes must be activated or repressed within restricted regions at specific times in order for normal cardiac development to proceed. In large part, this regulation of gene expression is controlled by an evolutionarily conserved set of transcription factors and microRNAs (miRNAs). Historically, the study of cardiac transcription factors has been very informative in understanding the early events in cardio- genesis. The rapidly evolving field of cardiac miRNAs promises to further extend our understanding of cardiac development. In this chapter, we will describe essential cardiac transcription factors and miRNAs and their role in controlling cardiac development.