LncRNA MRF targeting FSHR inhibits the osteogenic differentiation of BMSCs and bone defect repair through the regulation of the cAMP-PKA-CREB signaling pathway.

Background: Mesenchymal stem cells (MSCs), known for their ability to differentiate into osteoblasts, play a pivotal role in bone metabolism. In our previous investigations, we identified a novel long non-coding RNA (lncRNA) named MCP1 Regulatory Factor (MRF), which exhibits significant involvement in immune regulation of BMSCs. Moreover, we observed noticeable expression changes of MRF during the osteogenic differentiation of BMSCs. However, the exact role and underlying mechanism of MRF in the osteogenic differentiation of BMSCs remain elusive.

Methods: QRT-PCR analysis was employed to assess the expression levels of MRF. RNA interference and overexpression plasmids were utilized to modulate MRF expression, allowing for the observation of changes in the osteogenic differentiation capacity of BMSCs. Downstream pathways involved in the MRF-mediated regulation of BMSCs' osteogenic differentiation were predicted using transcriptome sequencing. The functionality of MRF in vivo was validated through a mouse tibial drilling defect model.

Results: In patients with osteoporosis, there is a notable increase in the expression of MRF within BMSCs. During the osteogenic differentiation of BMSCs, the MRF expression progressively decreases. The knockdown of MRF significantly enhances the osteogenic differentiation of BMSCs, promoting an increased expression of bone-related proteins such as RUNX2, ALP, and COL1A1. Transcriptome sequencing and western blot indicated that cAMP/PKA/CREB signaling pathway was significantly activated after lncRNA-MRF knockdown. Moreover, in the mouse tibial drilling defect model, MRF knockdown significantly promotes ossification in vivo.

Conclusions: MRF modulates the cAMP/PKA/CREB signaling pathway via the follicle stimulating hormone receptor (FSHR), thereby influencing the ossification differentiation of BMSCs. Our research suggests that MRF may serve as a potential target for bone-related disorders.