Exosomal miR-143-3p Derived from PCOS Follicular Fluid Induces Granulosa Cell Apoptosis by Targeting BMPR1A and Suppression of Smad1/5/8 Signaling
Abstract Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorders disease in women of reproductive age. The anovulation caused by abnormal follicular development is still the main characteristic of infertile patients with PCOS. Granulosa cells (GCs), an important component of follicular microenvironment, affect follicular development through GCs dysfunction. Increasing evidence indicates that exosomal miRNAs derived from follicular fluid (FF) of patients play critical roles during PCOS. However, which and how follicular fluid derived exosomal miRNAs play a pivotal role in controlling granulosa cells function and consequently follicular development remain largely unknown. Herein, we showed that miR-143-3p is highly expressed in follicular fluid exosomes of PCOS patients and can be delivered into granulosa cells. Furthermore, the functional experiments showed that the translocated miR-143-3p promoted granulosa cell apoptosis, which are important in follicle development. In terms of mechanism, we demonstrated that BMPR1A was identified as a direct target of miR-143-3p. Overexpression of BMPR1A reversed the effects of exosomal miR-143-3p on GCs apoptosis and proliferation by activating Smad1/5/8 signaling pathway. These results demonstrate that miR-143-3p-containing exosomes derived from PCOS follicular fluid promoted granulosa cell apoptosis by targeting BMPR1A and blockading Smad1/5/8 signaling pathway. Our findings provide a novel mechanism underlying the roles of exosomal-miRNA in follicular fluid of PCOS and facilitate the development of therapeutic strategies for PCOS.