Congenital heart diseases and biotechnology: Connecting by connexin

Heart development is a precisely harmonized process of cellular proliferation, migration, differentiation, and integrated morphogenetic interactions, and therefore it is extremely vulnerable to developmental defects that cause congenital heart diseases (CHD). One of the major causes of CHD has been shown to be the mutations in key cardiac channel-forming proteins namely, connexins (Cxs). Cxs are tetra-spanning transmembrane proteins that form gap junction channels and hemichannels on cellular membrane. They allow passage of small molecules or ions between adjacent cells or between cells and the extracellular environment. Studies have revealed that the spatiotemporal expression of Cxs mainly, Cx31.9, Cx40, Cx43, and Cx45 is essentially involved in early evelopmental events, morphogenetic transformations, maturation, and functional significance of heart. Our lab and others have shown that mutations in gap junction proteins could result in impaired trafficking, misfolding, and improper channel function of these proteins. It has also been shown that differential expressions of cardiac Cxs are associated with pathophysiological conditions of heart. Collectively, these conditions are coupled with abrogated or modified functionality of relevant channels in cardiac tissue, which are associated with many pathological situations, including CHD. Since CHD are a major cause of morbidity, therefore recovery of such kind of heart defects associated with Cxs is extremely important but remains highly challenging. In this review, we will summarize the role of Cxs in development, morphogenesis, maturation, normal function, and pathology of heart, and propose possible bioengineering techniques to recover defects in cardiac tissues related to the modified functions of Cxs. © (2014) Trans Tech Publications, Switzerland.