Intercellular Communication by Gap Junctions in the Cranial Neural Crest

Cell‐cell interactions and communication are critical for several fundamental biological processes that underscore vertebrate development, including cell migration and the formation of multicellular tissues. Much of the patterning that occurs during vertebrate embryogenesis is accomplished by neural crest cells, which are initially stationary but acquire the capacity to migrate through the epithelial‐to‐mesenchymal transition (EMT). Once motile, neural crest cells must communicate and interact with one another and with other cells, later differentiating to become sensory neurons and glia, the craniofacial cartilage and skeleton, portions of the heart, and skin pigment cells. The molecular basis by which neural crest cells establish intercellular communication during their initial formation and migration, however, is still not known. One unexplored means of such intercellular communication is through gap junctions that permit the passage of small molecules between connected cells. Gap junctions are comprised of Connexin proteins, of which Connexin 43 (Cx43) is the most abundant, with modulation of Cx43 previously shown to impact the formation of neural crest cell derivatives. Notably, mutations in Cx43 lead to oculodentodigital dysplasia, a disease characterized, in part, by craniofacial defects. To delineate a function for Cx43, and gap junctions, in cranial neural crest cell development, we first characterized the spatio‐temporal expression pattern of Cx43, noting it in premigratory neural crest cells, during EMT, and in fully migratory neural crest cells. Given this expression pattern, we next performed molecular and chemical perturbation assays to respectively alter Cx43 and gap junction function in neural crest cells. Our live imaging experiments reveal the presence of functional gap junctions in premigratory neural crest cells in vivo and in migratory neural crest cells cultured ex vivo . Moreover, gap junctions within the migratory neural crest cell population depend on Cx43 to properly transfer dye between cells. In keeping with this finding, chemical inhibition of general gap junction function, but not formation, abrogates neural crest cell EMT and/or migration in a reversible manner. Depletion of Cx43 from premigratory neural crest cells in vivo alters the expression of some neural crest cell markers but, interestingly, does not overtly affect EMT. These studies will decipher the roles of Cx43 and gap junctions in cranial neural crest cell EMT and migration, providing insight into the significance of intercellular communication during these key processes that are required for the formation of the vertebrate embryo. Support or Funding Information This research is supported by NIH R01DE024217 and American Cancer Society RSG‐15‐023‐01‐CSM grants. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .