ADAM9 deubiquitination induced by USP22 suppresses proliferation, migration, invasion, and epithelial-mesenchymal transition of trophoblast cells in preeclampsia.

INTRODUCTION: The dysregulation of deubiquitination has been shown to affect the development of pre-eclampsia (PE). A disintegrin and metalloprotease 9 (ADAM9) plays roles in diverse physiological contexts, including PE. Here, this study aimed to investigate whether ADAM9 regulated trophoblast cell dysfunction through ubiquitin-specific protease 22 (USP22) deubiquitinase-mediated deubiquitination during PE.

METHODS: Levels of genes and proteins were tested via qRT-PCR and western blotting assays. Cell proliferation, migration, and invasion were detected using cell counting kit-8, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell and wound healing assays, respectively. Epithelial-mesenchymal transition related markers were assayed using western blotting. Proteins between USP22 and ADAM9 were identified by co-immunoprecipitation assay.

RESULTS: ADAM9 was highly expressed in PE patients, functionally, ADAM9 overexpression weakened the proliferation, migration, invasion, and EMT progression in trophoblast cells. Mechanistically, the deubiquitinase USP22 removed ubiquitination on ADAM9 and maintained its stability. Forced expression of USP22 also suppressed the proliferation and mobility in trophoblast cells. Moreover, the regulatory effects of USP22 on trophoblast cells were reversed by ADAM9 silencing. In addition, USP22 interacted with ADAM9 to regulate the activation of Wnt/β-catenin pathway.

DISCUSSION: ADAM9 was deubiquitinated and stabilized by USP22 and then suppressed the proliferation, migration, invasion, and EMT progression in trophoblast cells, indicating a new pathway of USP10/RUNX1 axis in PE process.