LncRNA PVT1 Overexpression Improves Premature Ovarian Insufficiency by Inhibiting Granulosa Cell Apoptosis

Abstract

Background: Long noncoding RNA PVT1 (plasmacytoma variant translocation 1) is aberrantly expressed in a variety of cancers. However, whether PVT1 is aberrantly expressed in granulosa cells from premature ovarian insufficiency (POI) patients and the role of PVT1 in POI is largely unknown. Methods: The interaction between PVT1 and Foxo3a was confirmed by RNA pull-down and RNA immunoprecipitation (RIP) assays. Methylation level in PVT1 promoter region was detected by methylation-specific PCR. The subcellular location of PVT1 was detected by FISH assay. Granulosa cell apoptosis was detected using flow cytometry. The effect of PVT1 on the transcriptional activity of Foxo3a was detected by luciferase reporter assay. Results: PVT1 was down-regulated in ovarian tissues of POI group than control group, which was regulated by high methylation level. PVT1 was mainly localized in cytoplasm of granulosa cells. In addition, we determined PVT1 interacted with Foxo3a, down-regulation of PVT1 inhibited Foxo3a phosphorylation, resulting in the suppression of Foxo3a degradation and the increase of Foxo3a transcriptional activity. Moreover, down-regulation of PVT1 promoted granulosa cell apoptosis through Foxo3a. Finally, in vivo experiment showed that overexpression of PVT1 restored ovarian function in POI mice. Conclusion: Down-regulation of PVT1 inhibits Foxo3a phosphorylation that suppresses its degradation and activates the transcriptional activity of Foxo3a, thereby promoting granulosa cell apoptosis in POI. Funding Statement: This study was supported by International (Regional) Cooperation and Exchange (ICE) Projects of the National Natural Science Foundation of China (NSFC) (Grant No. 81820108016), Clinical Medical Research Fund of Chinese Medical Association-Reproductive Medicine Research and Development Projects for Youth Grant: Application study of human fetal primordial germ cells to oocyte differentiation and development in vitro (Grant No. 17020210690), and Henan Provincial Science and Technology Project: Study on the mechanism of meiosis initiation induced by human primordial germ cells to oocytes in vitro (Grant No. 182102310139). Declaration of Interests: All authors declare that they have no competing interests. Ethics Approval Statement: This study was approved by the Clinical Research Ethics Committee of the first affiliated hospital of Zhengzhou University (Ethical review number: 2019-KY-158). Written informed consents were obtained from all the patients involved. The animal experiment was approved by the Ethics Committee of the first affiliated hospital of Zhengzhou University.