The Hippo pathway has been associated with regulation of early follicle growth. Studies of murine ovaries suggest that changes in the actin cytoskeleton, caused by fragmentation, result in inhibition of the Hippo pathway, and in turn, may activate follicle growth. In humans, the connections between fragmentation, the actin cytoskeleton, and follicle activation are yet to be confirmed. In this study, we investigated the impact in vitro fragmentation of a human ovarian cortex on (a) actin polymerization, (b) components of the Hippo pathway, and (c) follicle growth in vivo. The results showed that the ratio between globular and filamentous actin remained unchanged at all timepoints (0, 10, 30, 60, 120, and 240 min) following tissue fragmentation. Neither was the Hippo pathway effector protein YES‐associated protein upregulated nor was gene expression of the downstream growth factors CCN2, CCN3, or CCN5 increased at any timepoint in the fragmented cortex. Furthermore, the number of growing follicles was similar in fragmented and intact cortex pieces after 6 weeks' xenotransplantation. However, the total number of surviving follicles was considerably lower in the fragmented cortex compared with intact tissue, suggesting detrimental effects of fragmentation on tissue grafting. These results indicate that fragmentation is likely to be ineffective to activate follicle growth in the human ovarian cortex.
In vitro activation of resting ovarian follicles, with the use of mechanical stress and/or pharmacological compounds, is an emerging and novel approach for infertility treatment. The aim of this study was to assess the sphingolipid, sphingosine-1-phosphate (S1P), as a potential in vitro activation agent in murine and human ovarian tissues and isolated follicles. Juvenile murine ovaries and donated human ovarian tissues, from 10 women undergoing ovarian tissue cryopreservation for fertility preservation, were incubated with or without 12 μM S1P for 3 h for quantitative PCR analysis, and 12 h for xenotransplantation or culture studies. Gene expression analyses were performed for genes downstream of the Hippo signaling pathway. Murine ovaries and isolated murine and human preantral follicles showed significantly increased mRNA expression levels of Ccn2/CCN2 following S1P treatment compared to controls. This increase was shown to be specific for the Hippo signaling pathway and for the S1P2 receptor, as co-treatment with Hippo-inhibitor, verteporfin and S1PR2 antagonist, JTE-013, reduced the S1P-induced Ccn2 gene expression in murine ovaries. Histological evaluation of human cortical tissues (5 × 5 × 1 mm; n = 30; three pieces per patient) xenografted for 6 weeks and juvenile murine ovaries cultured for 4 days (n = 9) or allografted for 2 weeks (n = 48) showed no differences in the distribution of resting or growing follicles in S1P-treated ovarian tissues compared to controls. Collectively, S1P increased Ccn2/CCN2 gene expression in isolated preantral follicles and ovarian tissue from mice and human, but it did not promote follicle activation or growth in vivo. Thus, S1P does not appear to be a potent in vitro activation agent under these experimental conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.