Chorionic Villous Mesenchymal Stem Cells Derived Exosomes Deliver miR-135b-5p to Trophoblasts, Promoting their Proliferation and Invasion by Targeting TXNIP via β-Catenin Pathway

Abstract Background: Human chorionic villous mesenchymal stem cells (CV-MSCs) are found to be a promising and effective treatment for tissue injury. Trophoblast dysfunction during pregnancies is significantly involved in the pathogenesis of preeclampsia (PE). This work was to understand how CV-MSCs regulated trophoblast function. Methods: In this study, we treated trophoblasts with CV-MSC-derived exosomes and RNA-seq analysis was used to understand the changes in trophoblasts. We examined the levels of TXNIP and β-catenin in trophoblasts by immunohistochemistry, western blot and qRT-PCR assays. Luciferase reporter assays and qRT-PCR assays were used to understand the role of miR135b-5p in the effects of CV-MSC-derived exosomes. The growth and invasion of trophoblasts was evaluated with the CCK-8 and transwell assays. Results: The treatment markedly enhanced the trophoblast proliferation and invasion. Furthermore, a significant decrease of TXNIP expression and inactivation of the β-catenin pathway in CV-MSCs exosomes-treated trophoblasts was observed. Consistent with these findings, TXNIP inhibition exhibited the same effect of promoting trophoblast proliferation and invasion as induced by CV-MSC-derived exosomes, also with the accompaniment of inactivation of β-catenin pathway. In addition, overexpression of TXNIP activated the β-catenin pathway in trophoblasts, and reduced the proliferation and invasion of trophoblasts. Importantly, miR135b-5p was found to be highly expressed in CV-MSC exosomes and interact with TXNIP. The miR-135b-5p overexpression significantly elevated the proliferation and invasion of trophoblasts, which could be attenuated by TXNIP overexpression. Conclusion: Our results suggest that TXNIP-dependent β-catenin pathway inactivation mediated by miR135b-5p which is delivered by CV-MSC-derived exosomes could promote the proliferation and invasion of trophoblasts.