Lithium chloride regulates connexin43 in skeletal myoblasts in vitro: possible involvement in Wnt/beta-catenin signaling.

Gap junction channels composed of connexin43 (Cx43) are essential for normal myogenic differentiation and skeletal muscle regeneration. Here, the aim was to study whether lithium chloride (LiCl) could regulate Cx43 expression and gap junction channel function by mimicking the Wnt/beta-catenin pathway in primary myoblasts. Cx43 mRNA expression in myoblasts was up-regulated in response to 5 mM LiCl. The enhanced Cx43 protein expression resulting from treatment with 5 and 10 mM LiCl for 24 h increased gap-junctional coupling in myoblasts. However, no obvious changes were observed with 20 mM LiCl. Furthermore, chronic treatment with 10 mM LiCl decreased Cx43 protein expression compared with untreated cells. The authors showed that LiCl mimicked the active canonical Wnt/beta-catenin signaling by glycogen synthase kinase-3beta (GSK-3beta) inactivation and accumulation of the effector protein beta-catenin into the nucleus. These results suggest that LiCl regulates Cx43 expression in skeletal myoblasts in vitro partly by a Wnt/beta-catenin-dependent pathway.