Impaired Communication through Gap Junctions Reduces the Angiogenic Potential of the Secretome in Mesenchymal Stromal Cell-Endothelial Cell Interactions In Vitro.

Highly specialized gap junctions play an important role in the interaction between endothelial (EC) and multipotent mesenchymal stromal cells (MSC). Inhibition of gap junctions with a specific inhibitor carbenoxolone attenuates the effects of the medium conditioned by MSC-EC co-culture on proliferation and migration of cultured EC. In conditioned medium from co-culture, the levels of angiogenic mediators (VEGF-A, FGF-2, MCP-1, etc.) were decreased, which apparently determines lower angiogenic effect of the conditioned medium on the growth of the vascular network in the chorioallantois membrane of quail embryo in ovo. Suppression of communication through gap junctions in associations of MSC and EC, the structural and functional units of physiological and reparative angiogenesis, can directly reduce the level of proangiogenic mediators in the microenvironment, which, in turn, can help to control the regulation of vascular function in pathologies.