Roles of connexins in atherosclerosis and ischemia-reperfusion injury

Connexins are members of a large family of transmembrane proteins that oligomerize to form connexons or hemichannels, and connexons of adjacent cells dock to make gap junction channels. These channels allow the exchange of ions and small metabolites between the cytosol and extracellular space, or between the cytosols of neighbouring cells. Connexins are important in cardiovascular physiology; they support conducted vascular responses and allow for coordinated contraction of the heart. Four main connexins are expressed in the cardiovascular system: Cx37, Cx40, Cx43 and Cx45. Their expression pattern is not uniform and depends on intrinsic and environmental factors. Significant changes in the expression pattern, the cellular localization and the opening of connexin channels have been described during the development of atherosclerosis and after ischemia and reperfusion. In this review, we provide an overview of the roles of different connexins in these pathologies.