TITLE:
Effects of Combined BMP9 and bFGF Treatment on Runx2 and Col1 mRNA Expression in MC3T3-E1 Cells
AUTHORS:
Yaqiu Chen, Yuzhao Chen, Chang Liu, Peng Tang, Feng Qiu, Yewei Xin, Rilang Feng, Han Jiang, Xiaojing Sun, Qian Jiang
KEYWORDS:
BMP9, bFGF, MC3T3-E1 Cells, Runx2, Col1, Osteogenic Differentiation, qRT-PCR, Synergistic Effects
JOURNAL NAME:
Open Journal of Orthopedics,
Vol.15 No.11,
November
28,
2025
ABSTRACT: Objective: To investigate the synergistic effects of bone morphogenetic protein 9 (BMP9) and basic fibroblast growth factor (bFGF) at different concentration combinations on the mRNA expression of osteogenic markers Runx2 and Col1 in the mouse osteoblast precursor cell line MC3T3-E1. Methods: MC3T3-E1 cells were treated with BMP9 (10 ng/mL or 200 ng/mL) and bFGF (10 ng/mL or 100 ng/mL), either individually or in combination. Real-time quantitative PCR (qRT-PCR) was employed to measure the relative expression levels of Runx2 and Col1 mRNA at day 4 (D4) and day 7 (D7) post-treatment. Results: At D4, individual BMP9 treatment promoted Runx2 expression, with BMP9min (10 ng/mL) showing the strongest effect. However, combined BMP9 and bFGF treatment significantly suppressed Runx2 expression compared to BMP9 alone, indicating antagonistic interactions at this early timepoint. For Col1 expression at D4, combined treatments showed modest increases compared to negative control but remained lower than BMP9 monotherapy. At D7, while both BMP9 and bFGF monotherapy groups demonstrated significantly elevated expression of Runx2 and Col1 compared to negative control, combined treatments continued to show suppressive effects compared to BMP9 monotherapy. The presence of bFGF consistently attenuated BMP9-induced osteogenic marker expression at both timepoints. Conclusion: BMP9 and bFGF exhibit persistent antagonistic interactions in regulating osteogenic differentiation markers Runx2 and Col1. At both D4 and D7 timepoints, the addition of bFGF to BMP9 treatment consistently suppressed the osteogenic-promoting effects of BMP9 monotherapy, despite both growth factors showing elevated expression compared to negative control at D7. These findings challenge the presumed synergistic relationship between BMP and FGF family members and suggest that bFGF may interfere with BMP9-mediated osteogenic signaling pathways. For bone tissue engineering applications, these results indicate that careful consideration must be given to growth factor combinations, as co-delivery of BMP9 and bFGF may not enhance, and could potentially impair, osteogenic outcomes compared to BMP9 alone.