#220 : PDGFBB Improved the Biological Function of Menstrual Blood-Derived Stromal Cells and the Anti-Fibrotic Properties of Exosomes

Abstract

Background and Aims: Intrauterine adhesion (IUA) is a reproductive dysfunction disease characterized by endometrial fibrosis, with limited therapeutic options and poor prognosis. Our previous studies confirmed that menstrual blood-derived stromal cells (MenSCs) effectively attenuated endometrial fibrosis in IUA rats mainly through exosomes. This therapeutic effect can be enhanced by platelet-rich plasma (PRP), in which PDGFBB is an abundant growth factor. Therefore, we aimed to compare the effects of PRP and PDGFBB on the biological activities of MenSCs in vitro, and to further evaluate the molecular mechanism of MenSCs-derived exosomes (MenSCs-exos) in alleviating endometrial fibrosis. Method: MenSCs were isolated for in vitro functional assays to examine the viability, migration, and stemness of MenSCs. Endometrial stromal cells (EndoSCs) were treated with 50 ug/ml of MenSCs-exos, obtained by differential ultracentrifugation extraction. The molecular mechanisms by which PDGFBB improves MenSCs and exosomes alleviate EndoSCs fibrosis were then explored using immunofluorescence, western blot, and co-immunoprecipitation. Results: Both 100 ng/ml PDGFBB and 10% activated PRP promoted the proliferation and inhibit apoptosis of MenSCs in vitro. Compared with PRP, PDGFBB significantly promoted MenSCs migration. All of these effects were inhibited by the PDGFR-[Formula: see text] inhibitor sorafenib. PRP and PDGFBB activated AKT/NF-[Formula: see text]B signaling pathway in MenSCs and increased the expression of P65 and OCT4. Moreover, pretreatment of PDGFBB did not increase the secretion of MenSCs but significantly increased the anti-fibrosis effects of MenSCs-exos in IUA-EndoSCs. MenSCs-exos attenuated SMAD3 phosphorylation and increased YAP ubiquitination, which reduced the binding of YAP/SMAD3. Pretreatment with PDGFBB amplifies this effect. Conclusion: In summary, PDGFBB could improve the biological functions of MenSCs via AKT/NF-[Formula: see text]B signaling pathway, including viability, migration, and stemness. PDGFBB amplified MenSCs-exos to attenuate endometrial fibrosis by inhibiting YAP activity, revealing a novel mechanism by which PRP enhanced MenSCs to repair tissue injury and providing a potential option for improving stem cell efficacy in IUA.