Construction of a Lentiviral Vector for Fgfr2 Overexpression and its Impact on the Biological Behavior of Cranial Suture Mesenchymal Stem Cells

Objective: Suture mesenchymal stem cells (SuSCs), possessing self-renewal and multilineage differentiation abilities, play a crucial role in cranial bone growth. However, the impact of the disease-causing fibroblast growth factor receptor 2 (FGFR2) mutation on SuSCs in Crouzon syndrome has not been explored. This study aims to employ a lentivirus to overexpress Fgfr2 and investigate its role in the pathogenesis of Crouzon syndrome. Methods: Starting with the prevalent FGFR2 mutation site in patients with Crouzon syndrome, a lentiviral vector carrying the Fgfr2.C361Y mutation was developed and transfected into SuSCs, with a determined multiplicity of infection values. The experimental group, SuSCs+ Fgfr2.C361Y , was compared with the empty vector and normal SuSC groups. Cell proliferation, cycle, apoptosis, and osteogenic functionality were assessed using CCK-8 assays, flow cytometry, ALP activity assays, and real-time quantitative polymerase chain reaction. Results: The lentiviral vector effectively infected SuSCs, leading to heightened Fgfr2 expression, with optimal multiplicity of infection values of 80. The experimental group demonstrated decreased proliferation activity and a higher apoptosis rate compared with controls ( P < 0.05). After osteogenic induction, the experimental group showed significantly higher ALP activity than controls ( P < 0.05). Real-time quantitative polymerase chain reaction indicated lower mRNA expression levels of Gli1 , Axin2, Pcna, Cdk2, and Bcl-2 in the experimental group than controls, whereas Bax, Runx2 , and Bmp-2 showed higher expression ( P < 0.05). Conclusion: This study constructed a lentivirus vector to upregulate Fgfr2 expression in SuSCs, suppressing stem cell stemness by inhibiting proliferation, promoting apoptosis, and accelerating premature osteogenic differentiation, resulting in premature suture closure. These findings establish the groundwork for further understanding the pathogenesis of Crouzon syndrome.