Exploring the Potent Roles of an Internally Translated Truncated Connexin-43 Isoform

Abstract

Connexin 43 (Cx43) is an essential regulator in cardiovascular physiology, responsible for intercellular communication within the heart. The role of Cx43 in maintaining beat-to-beat cardiac excitation and cardiac function underscores its significance. Alterations in Cx43 expression and localization have been implicated in pathologies from sudden cardiac death to heart failure. Essential to Cx43 function is its intrinsic ability to form diverse isoforms through internal translation of GJA1 mRNA. Evidence has accumulated that GJA1-20k, the most abundant of these isoforms, is necessary for Cx43 trafficking and localization. GJA1-20k has been recognized to have a wide range of additional functions beyond directing Cx43-based intercellular communication, including cytoskeletal modulation, maintaining mitochondrial homeostasis, protecting against oxidative stress, and mediating mitochondrial preconditioning. The involvement of GJA1-20k in these processes confers it great therapeutic potential, especially in treating cardiovascular diseases such as myocardial infarction, ischemia/reperfusion injuries, and arrhythmias. Administration of GJA1-20k mitigates the underlying cellular pathophysiological disturbances that develop as a result of these diseases. Numerous studies have documented the therapeutic efficacy of GJA1-20k gene therapy in animal models of cardiovascular disease. The translational impact of these studies opens up new treatment avenues through the use of gene therapy targeting novel mechanisms of action.