Autologous or artificial bone grafts have been widely used to repair maxillofacial bone defects clinically, but these methods still suffer from insufficient osteogenesis. Bone marrow mesenchymal stem cells play a key role in the bone formation. Notably, ectoderm-derived jaw bone marrow mesenchymal stem cells have stronger proliferation and osteogenic differentiation capacity compared with mesoderm-derived iliac bone marrow mesenchymal stem cells, elucidating the key mechanisms involved. It is expected to provide a new strategy for the repair of craniomaxillofacial bone defects.

To compare the biological differences between human jaw bone marrow mesenchymal stem cells and iliac bone marrow mesenchymal stem cells and identify the key regulatory genes.

(1) Jaw bone and iliac bone were collected from three patients with alveolar cleft. Primary bone marrow mesenchymal stem cells were isolated and cultured. Cell proliferation ability was detected by colony formation assay. Cell senescence was detected by β-galactosidase staining assay. Senescence and osteogenesis-related protein expression levels were detected by western blot assay. Osteogenic ability was detected by alizarin red staining after osteogenic induction solution treatment. (2) Jaw bone marrow mesenchymal stem cells and iliac bone marrow mesenchymal stem cells were subjected to transcriptome and differential gene expression analysis to find the 20 genes with the largest differential expression and identify the key regulatory factors. (3) The gene in iliac bone marrow mesenchymal stem cells were knocked down to comparatively analyze the changes in self-renewal, anti-aging and osteogenic capacity of iliac bone marrow mesenchymal stem cells. (4) The gene-edited iliac bone marrow mesenchymal stem cells were loaded into β-tricalcium phosphate scaffolds and implant into nude mice for 8 weeks. The scaffolds were stained with Masson staining and immunofluorescence staining to observe the difference in osteogenic capacity.

(1) Jaw bone marrow mesenchymal stem cells have stronger proliferation, anti-aging and osteogenic differentiation abilities compared to iliac bone marrow mesenchymal stem cells. (2) By transcriptome analysis, we identified HOXA10 as a highly up-regulated core transcription factor in iliac bone marrow mesenchymal stem cells. (3) After knocking down HOXA10 in iliac bone marrow mesenchymal stem cells, we observed a significant increase in proliferation, anti-aging, and osteogenic differentiation abilities. (4) After HOXA10 knocked-down iliac bone marrow mesenchymal stem cells/β-tricalcium phosphate was implanted subcutaneously on the back of nude mice, and their bone formation ability was stronger. (5) The above results suggest that HOXA10 is a key regulatory gene that determines the proliferative, anti-aging and osteogenic differentiation abilities of bone marrow mesenchymal stem cells. HOXA10 gene-modified iliac bone marrow mesenchymal stem cell transplantation can be used as a potential application strategy for repairing maxillofacial bone defects.