Engineering modification of human umbilical cord mesenchymal stem cell-derived small extracellular vesicles ameliorates polycystic ovary syndrome by enhancing the ovarian environment and regulating follicular development.

Background: Polycystic Ovary Syndrome (PCOS), is a complex endocrine disorder affecting 6-21% of reproductive-aged women, characterized by chronic anovulation, hyperandrogenism, and polycystic ovarian morphology. Current clinical management relies on lifestyle modifications and symptom-targeted therapies due to the absence of curative interventions. In recent years, Laparoscopic ovarian drilling (LOD), a surgical procedure that induces controlled ovarian damage to stimulate primordial follicle activation and regulate follicular growth, has emerged as an established therapeutic intervention for infertility in PCOS. Beyond surgical approaches, the 740Y-P peptide-PI3K-Akt pathway agonist can achieve similar effects to LOD in enhancing follicular activation and restoring fertility. However, translating 740Y-P into clinical practice remains challenging due to systemic delivery limitations, including poor bioavailability and inadequate ovarian targeting. To address this, naturally secreted sEVs have gained attention as versatile therapeutic vectors owing to their intrinsic immunomodulatory properties and homing tendency.

Methods: In this study, We engineered HucMSC-sEVs through anchor peptide-mediated surface Connections to deliver the 740Y-P peptide. The N-terminus of 740Y-P was conjugated to the C-terminus of the CD63-binding anchor peptide, enabling exogenous loading via co-incubation (4 °C, 12h). Engineered sEVs were characterized for peptide loading efficiency and targeting capability. PCOS model mice were treated by tail vein injection. The phenotype studies were explored by glucose homeostasis, insulin sensitivity, ovarian weight, ovarian morphometric analysis, follicle counts and litter size. The mechanisms were also investigated by immunohistochemistry, immunofluorescence, western blot, RT-qPCR and TUNEL assays. And compared the different efficacy of 740Y-P peptide, sEVs, and 740Y-P loaded sEVs.

Results: Our results demonstrated that sEVs functioned as dual-effect agents-serving both as immunomodulators and targeted delivery vehicles for 740Y-P, significantly improved ovarian microenvironment and enhanced ovarian targeting efficiency of 740Y-P. The engineered sEVs restored estrous cycles, ameliorated glucose-insulin homeostasis, reduced ovarian inflammation and granulosa cell apoptosis. Additionally, activated the PI3K/Akt signaling pathway to promote follicular maturation, reduce ovarian cyst formation and ultimately increase litter size, improving metabolic and reproductive outcomes in PCOS mice.

Conclusions: In this study, we engineered sEVs to deliver the 740Y-P peptide, demonstrating their capacity to mitigate ovarian inflammation, normalize follicular development, and enhance fertility in a PCOS mouse model. These findings propose a novel therapeutic strategy for PCOS, pending further optimization of delivery protocols and clinical validation.