Connexin Gap Junction Proteins in Development and Disease

Abstract

Connexins form tightly‐regulated large‐pore channels that facilitate the passage of various ions, metabolites, and signaling molecules directly between cells, or in some cases and/or pathologies, to the extracellular milieu. The human connexin encoding gene family consists of 21 members and mutations in half of these genes leads to over two dozen diseases ranging in severity from manageable developmental abnormalities to life‐shortening organ failure. Developmentally, connexin expression and gap junctional intercellular communication begins at the 8 cell stage and persists throughout organogenesis resulting in most adult cells expressing two or more connexin subtypes. Connexin genes are exquisitely regulated during all developmental processes before birth, and in many tissues like the skin, after birth. Connexins regulate their function by channel gating processes and notably through their turnover owing to their short half‐life of only a few hours. Given their ubiquitous distribution it is not at all surprising that gene mutations lead to disease. In fact, it is probably more surprising that patients harbouring connexin gene mutations do not present with more clinical morbidities. Our laboratory has used tissue‐relevant cells, primary cells, organotypic cultures, mouse models of human diseases, and induced pluripotent stem cells from connexin‐linked disease patients to uncover ten distinct mechanisms by which connexin gene mutations cause disease. Collectively, connexin‐disease linked mutants have been classified into distinct gain‐ and loss‐of function molecular mechanisms of action. Our long‐term goals include developing strategies to compensate or overcome the cellular and tissue defects triggered by these mutants. This presentation will discuss how connexins have emerged as therapeutic targets in disease and in injury repair. We anticipate that once it is better understood how connexin gene mutations cause disease and abnormalities, which often present more acutely during aging, these findings could be translated into pre‐clinical studies leading to possible treatments for gap junction‐linked diseases.Support or Funding InformationSupported by the Canadian Institutes of Health Research.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.