SKAP2 is downregulated in the villous tissues of patients with missed abortion and regulates growth and migration in trophoblasts through the WAVE2-ARP2/3 signaling pathway.

Introduction: Abnormal placental trophoblast function is the main cause of missed abortion (MA). Src kinase-associated phosphoprotein 2 (SKAP2) indirectly affects actin reunion, which is significantly associated with cell migration.

Methods: Twenty women with MA and 20 healthy women who underwent voluntarily induced abortion were included in this study. Immunohistochemistry, qRT-PCR, and western blotting were used to determine SKAP2, WAVE2, and ARP2 expression in the villous tissues. We investigated the effects of SKAP2 and the W336K mutant (blocked SKAP2 Src homology 3 function) on growth and migration in HTR8/SVneo cells using the CCK8 assay, flow cytometry, and transwell assay. The effects of SKAP2 on the WAVE2-ARP2/3 signaling pathway in HTR8/SVneo cells were evaluated by western blotting and immunofluorescence.

Results: Compared to the women in the voluntary abortion group, SKAP2 and WAVE2 expression levels were downregulated in the villous of patients with MA. In HTR8/SVneo cells, SKAP2 siRNA silencing regulated the growth and migration, while SKAP2 overexpression promoted growth and migration, and inhibited apoptosis. Additionally, SKAP2 regulated the expression of WAVE2 and ARP2, as well as the colocalization of actin with WAVE2. The SKAP2 W336K mutant could not alter WAVE2 and ARP2 expression, nor HTR8/SVneo cell growth and migration, with or without SKAP2 siRNA transfection.

Discussion: SKAP2 could activate the WAVE2-ARP2/3 pathway resulting in an increase of growth and migration in trophoblasts. SKAP2 probably played an important role in MA by affecting the growth and migration of trophoblasts.