Inhibition of endothelial wound repair by dominant negative connexin inhibitors

Wounding of endothelial cells is associated with altered direct intercellul ar communication. To determine whether gap junctional communication partici pates to the wound repair process, we have compared connexin (Cx) expressio n, cell-to-cell coupling and kinetics of wound repair in monolayer cultures of PymT-transformed mouse endothelial cells (clone bEnd.3) and in bEnd.3 c ells expressing different dominant negative Cx inhibitors. In parental bEnd .3 cells, mechanical wounding increased expression of Cx43 and decreased ex pression of Cx37 at the site of injury, whereas Cx40 expression was unaffec ted. These wound-induced changes in Cx expression were associated with func tional changes in cell-to-cell coupling, as assessed with different fluores cent tracers. Stable transfection with cDNAs encoding for the chimeric conn exin 3243H7 or the fusion protein Cx43-beta Gal resulted in perturbed gap j unctional communication between bEnd.3 cells under both basal and wounded c onditions. The time required for complete repair of a defined wound within a confluent monolayer was increased by similar to 50% in cells expressing t he dominant negative Cx inhibitors, whereas other cell properties, such as proliferation rate, migration of single cells, cyst formation and extracell ular proteolytic activity, were unaltered. These findings demonstrate that proper Cx expression is required for coordinated migration during repair of an endothelial wound.