Regulation of Bone Morphogenetic Protein Receptor Type II Expression by /Fragile X Mental Retardation Protein in Human Granulosa Cells in the Context of Poor Ovarian Response.

Fragile X mental retardation protein (FMRP) is a translational repressor encoded by . It targets bone morphogenetic protein receptor type II (BMPR2), which regulates granulosa cell (GC) function and follicle development. However, whether this interaction affects folliculogenesis remains unclear. Therefore, this study investigated the potential effect of FMRP-BMPR2 dysregulation in ovarian reserves and infertility. COV434 cells and patient-derived GCs were used to evaluate FMRP and BMPR2 expression. Similarly, , , , and expression were evaluated in GCs with normal (NOR) and poor (POR) ovarian responses. FMRP and BMPR2 were expressed in both cell types. They were co-localized to the nuclear membrane of COV434 cells and cytoplasm of primary GCs. silencing increased the mRNA and protein levels of BMPR2. However, the mRNA levels of and were significantly lower in the POR group. and levels were strongly positively correlated in the NOR group but weakly correlated in the POR group. Additionally, expression was significantly reduced in the POR group. This study highlights the crucial role of /FMRP in the regulation of expression and its impact on ovarian function. These findings indicate that the disruption of FMRP-BMPR2 interactions may cause poor ovarian responses and infertility.