RUVBL1 and CRAF promote periodontal ligament stem cell osteogenic differentiation via the MEK/ERK signaling cascade

MAPK signaling is key for osteogenic differentiation of periodontal ligament stem cells (PDLSCs), a process important in treating periodontal injury. RuvB‑like AAA ATPase‑1 (RUVBL1) binds C‑Raf proto‑oncogene serine/threonine‑protein kinase (CRAF) to activate the MAPK signaling pathway, but the specific roles and mechanisms of RUVBL1 and CRAF in PDLSCs remain unclear. In the present study, PDLSCs were subjected to lentiviral transfection for RUVBL1 and CRAF expression manipulation. Flow cytometry was performed to characterize mesenchymal SC (MSC) features. A Cell Counting Kit‑8 assay was used to assess PDLSC proliferative viability. Lipogenic differentiation potential was evaluated using Oil Red O staining following lipogenic induction. Alkaline phosphatase and alizarin red staining were utilized to assess osteogenic differentiation potential and mineralization, respectively, following osteogenic induction. Reverse transcription‑quantitative PCR and western blotting were conducted to determine the effects of RUVBL1 and CRAF on the MAPK signaling pathway in PCLSCs. PDLSCs were determined to be SCs exhibiting self‑renewal and MSC characteristics, including lipogenic and osteogenic differentiation potential. RUVBL1 overexpression enhanced PDLSC osteogenic differentiation while inhibiting proliferative activity and lipogenic differentiation. Conversely, CRAF overexpression promoted PDLSC proliferative activity, as well as osteogenic and lipogenic differentiation. Knockdown of RUVBL1 reduced osteogenic differentiation while enhancing proliferative activity and lipogenic differentiation, whereas knockdown of CRAF suppressed proliferative activity, osteogenic differentiation and lipogenic differentiation. RUVBL1 did not regulate CRAF in PDLSCs. However, overexpression of RUVBL1 or CRAF promoted MEK and ERK phosphorylation, activating the MEK/ERK signaling pathway. Overall, RUVBL1 and CRAF activated the MEK/ERK signaling pathway to promote osteogenic differentiation in PDLSCs, although RUVBL1 did not regulate CRAF.