HGF promotes HTR-8/SVneo cell migration through activation of MAPK/PKA signaling leading to up-regulation of WNT ligands and integrins that target β-catenin.

Inadequate migration and invasion of the trophoblast cells during embryo implantation is one of the reasons for pregnancy-related complications such as intrauterine growth restriction and preeclampsia. In the present study, relevance of WNT ligands and integrins associated with hepatocyte growth factor (HGF)-mediated migration of HTR-8/SVneo trophoblastic cells has been investigated. Treatment of HTR-8/SVneo cells with HGF led to a dose-dependent increase in their migration. RT-PCR studies revealed a significant increase in the transcripts of WNT4, WNT11, ITGA2, and ITGAV, which was further confirmed at protein level by Western blotting. HGF treatment also led to increased expression of integrin α2β1 and αVβ5 in HTR-8/SVneo cells. Silencing of WNT4, WNT11, ITGA2, and ITGAV by siRNA led to a significant decrease in HGF-mediated migration of cells. Treatment of cells with HGF led to activation of mitogen-activated protein kinases (MAPK) and protein kinase A (PKA) signaling pathways. Inhibition of MAPK/PKA, by selective inhibitors, led to decrease in the expression of above WNT ligands and integrins. Silencing of WNT4/WNT11 led to concomitant decrease in the expression of ITGA2 and ITGAV and vice versa. HGF treatment also led to significant increase in β-catenin expression, a downstream target of both WNT ligands and integrins. Silencing of β-catenin led to decrease in HGF-mediated migration. β-catenin expression was also down-regulated in WNT4/WNT11/ITGA2/ITGAV silenced cells suggesting a possible cross-communication of WNT ligands and integrins via β-catenin. These studies have established the significance of WNT4/WNT11 as well as ITGA2/ITGAV during HGF-mediated migration of HTR-8/SVneo trophoblastic cells.