Involvement of gap junctional communication and connexin expression in trophoblast differentiation of the human placenta

Abstract

Gap junctional intercellular communication (GJIC) permits coordinated cellular activities during development and d ifferentiation processes, and its dysfunction or mutation of connexin genes have been implicated in pathologies. In the human placenta, two distinct differentiation pathways of cytotrophoblastic cell coexist leading to a double model: fusion phenotype (villous trophoblast) a nd proliferative/ invasive phenotype (extravillous trophob last). This review focuses on current knowledge on the connexin expression and the implication of GJIC in trophoblastic differentiation. Experimental evidence obtained in human placenta demonstrates the involvement of connexin 43-gap junctions in the trophoblastic fusion process and of a connexin switch during the spatially and temporally controlled proliferation/invasion process.