Secretome from human placenta–derived mesenchymal stem cells rescues ovarian function and circadian rhythm in mice with cyclophosphamide-induced primary ovarian insufficiency

Primary ovarian insufficiency (POI) is an early decline in ovarian function that leads to infertility. Conventional treatments for chemotherapy-induced POI are unsatisfactory. Mesenchymal stem cells (MSCs) have emerged as a therapeutic option, but the impact of estrogen niche-respond MSC secretome on ovarian regeneration and circadian rhythm remains unknown. This study revealed that the secretome of ER+pcMSCs (conditioned medium [CM] and E2-CM, respectively) significantly reduced the CTX-induced defects in ovarian folliculogenesis and circadian rhythm. The CM/E2-CM also reduced granulosa cell apoptosis and rescued angiogenesis in POI ovarian tissues. E2-CM presented a better effect than the CM. Cytokine array analysis showed a significant increase in cytokine/growth factors associated with immunomodulation and angiogenesis (including angiogenin). Neutralizing angiogenin in the CM/E2-CM significantly decreased its ability to promote HUVEC tube formation in vitro. Importantly, the ER+pcMSC secretome restored the CTX-induced circadian rhythm defects, including the expression of both the genes and proteins associated with ovarian circadian clock (such as Rora, E4bp4, Rev-erbα, and Dbp) and the locomotor activity. Further exosomal miRNA analysis showed the involved miRNAs in targeting the genes associated with POI rescue (Pten and Pdcd4), Caspase-3, estrogen synthesis (Cyp19a1), and importantly the ovarian clock regulation (E4bp4, Rev-erbα and Rev-erbβ). Conditioned medium (CM) and estradiol-conditioned medium (E2-CM) were generated by priming estrogen receptor-expressing MSCs (ER+pcMSCs) from human placenta with or without estradiol (100 nM). POI models were established using C57BL/6 mice (in vivo) and KGN cells (in vitro) treated with cyclophosphamide (CTX) or 4-hydroperoxycyclophosphamide (4-OOH-CP) to evaluate CM/E2-CM’s therapeutic efficacy. The expressions of clock-controlled genes/proteins were detected by RT-qPCR, western blotting, and immunohistochemistry assays. Locomotor activity experiments assessed behavioral circadian rhythmicity. The cytokine array and miRNA sequencing were performed to explore the potential underlying mechanism of CM/E2-CM in POI treatment.