Activation of peroxisome proliferator-activated receptor gamma by human cytomegalovirus for de novo replication impairs migration and invasiveness of cytotrophoblasts from early placentas.

Human cytomegalovirus (HCMV) contributes to pathogenic processes in immunosuppressed individuals, in fetuses, and in neonates. In the present report, by using reporter gene activation assays and confocal microscopy in the presence of a specific antagonist, we show for the first time that HCMV infection induces peroxisome proliferator-activated receptor gamma (PPARgamma) transcriptional activity in infected cells. We demonstrate that the PPARgamma antagonist dramatically impairs virus production and that the major immediate-early promoter contains PPAR response elements able to bind PPARgamma, as assessed by electrophoretic mobility shift and chromatin immunoprecipitation assays. Due to the key role of PPARgamma in placentation and its specific trophoblast expression within the human placenta, we then provided evidence that by activating PPARgamma human cytomegalovirus dramatically impaired early human trophoblast migration and invasiveness, as assessed by using well-established in vitro models of invasive trophoblast, i.e., primary cultures of extravillous cytotrophoblasts (EVCT) isolated from first-trimester placentas and the EVCT-derived cell line HIPEC. Our data provide new clues to explain how early infection during pregnancy could impair implantation and placentation and therefore embryonic development.