LncRNA S100PBP promotes proliferation and steroid hormone synthesis of granulosa cells by sponging MiR-2285bc-BMPR2 in bovine

Abstract In bovine follicular development, the proliferation of bovine granulosa cells affects follicular selection, atresia, and cystic follicle formation. When cystic follicles appear on the ovaries, granulosa cells stop proliferating, resulting in the reduction of granulosa cells layer. In our previous study, the whole transcriptome sequencing revealed that Bone morphogenetic protein receptor 2 (BMPR2) was differentially expressed between cystic and normal follicular granulosa cells. We speculated that long noncoding RNA may act as competing endogenous RNA targeting microRNAs and then regulating the expression of BMPR2 and the function of granulosa cells, thereby affecting follicular development and cyst formation. In this study, the results elucidated that long noncoding RNA S100PBP (NONBTAT011846.2) directly bound miR-2285bc, which targeted in the BMPR2 3′-UTR. miR-2285bc suppresses granulosa cells proliferation by downregulating BMPR2 expression. Furthermore, long noncoding RNA S100PBP was silenced by small interfering RNA, and long noncoding RNA S100PBP regulated BMPR2 expression by sponging miR-2285bc investigated through cross-verification. When small interfering RNA of long noncoding RNA S100PBP was transfected into granulosa cells, the results revealed similar molecular changes as those transfected with miR-2285bc mimics. Silencing long noncoding RNA S100PBP or overexpressing miR-2285bc altered the expressions of some follicular development-related genes, which could be related to follicular cyst occurrence. In conclusion, our findings support that long noncoding RNA S100PBP regulates the expression of BMPR2 through sponge miR-2285bc, promotes the proliferation of granulosa cells, inhibits their apoptosis, and increases the synthesis and secretion of follicular steroid hormones, thus promoting the development of bovine follicles.