Ckb-Cryab-Drp1 axis enhances BMSC osteogenic differentiation and mouse alveolar bone healing through mitochondrial fission modulation.

Repairing bone defects resulting from trauma, infection, or tumor resection remains a significant challenge in clinical practice. Particularly in the oral and maxillofacial region, achieving predictable bone regeneration is especially difficult due to the complex anatomical structure and the critical need for optimal aesthetic and functional outcomes. A deeper understanding of the molecular mechanisms governing osteogenic differentiation is therefore essential to develop effective strategies for bone repair. Although creatine kinase B (Ckb) is known for its role in energy metabolism, its function in bone regeneration remains poorly understood. In this investigation, we found that Ckb is specifically expressed in jaw mesenchymal cells. Functional assays demonstrated that Ckb promoted osteogenic differentiation of bone marrow mesenchymal stem cells in vitro. Consistently, Ckb overexpression promoted alveolar bone healing in a mouse tooth-extraction model, while Ckb knockdown impaired bone regeneration. We discovered that Ckb localized to mitochondria and enhanced mitochondrial fission by increasing dynamin-related protein 1 (Drp1) Ser616 phosphorylation. The pro-osteogenic impact of Ckb was reduced by pharmacologically inhibiting mitochondrial fission with Mdivi-1. This result was replicated by Drp1 knockdown, indicating that Drp1 is essential for Ckb-mediated osteogenesis. Transcriptome sequencing identified αB-crystallin (Cryab) as a key downstream effector of Ckb, and co-immunoprecipitation confirmed a physical interaction between Ckb and Cryab. Crucially, Cryab overexpression rescued the osteogenic and mitochondrial dysfunction caused by Ckb knockdown. Collectively, our research reveals a unique Ckb-Cryab-Drp1 axis that controls mitochondrial dynamics to coordinate osteogenesis, offering a molecular basis for guiding MSC-based bone regeneration techniques.