Analysis Of Human Bone Marrow Mesenchymal Stem Cell Subgroups Based On Single-cell Transcriptome Sequencing Technology And Research On The Pathogenesis Of Osteoporosis

Objective: To analyze the heterogeneity of normal human bone marrow mesenchymal stem cells,analyze the differences and functions of different subgroups.And through the comparison with bone marrow mesenchymal stem cells of patients with osteoporosis,explore the pathogenesis and mechanism of osteoporosis.Methods: From the collected bone marrow,extract mononuclear cells,extract mesenchymal stem cells by immunomagnetic bead method,and perform single-cell transcriptome sequencing after quality control.According to the sequencing results,the normal group and osteoporotic group cells are divided into groups.Cell subpopulations are analyzed to clarify the differential genes,and GO and KEGG enrichment analysis are performed based on the differential genes,and finally the cell subpopulations are analyzed to find out the changes in mesenchymal stem cells during the occurrence and development of osteoporosis.Results: In this study,17899 cells from healthy BMSCs samples were extracted;19,096 cells from BMSCs samples from patients with osteoporosis were extracted.According to the Graph-based clustering method,the healthy control group BMSCs were divided into 14 cell subgroups,and 13 cell subgroups in the osteoporosis group.Except for the osteogenic differentiation subgroup,which was not found in the osteoporosis group,all the other subgroups were One-to-one correspondence with the normal group.The first 20 genes differentially expressed in each subgroup were selected as the characteristic genes of the subgroup,and GO and KEGG enrichment analysis were performed based on these genes.The results found that the normal group of mesenchymal stem cell subgroup 3 and subgroup 12 expressed many differentiation-related genes,showing the potential of BMSCs multi-directional differentiation,while other subgroups are more related to immune regulation or system function.Osteogenic differentiation genes are highly expressed in these two subgroups,especially subgroup 12,so we define subgroup 12 as the subgroup of osteogenic differentiation lines.We also compared the overall gene expression of BMSCs in the normal group and BMSCs in the osteoporosis group,and the results showed that there were a total of 5,615 down-regulated genes and 2,478 up-regulated genes.Among them,the expression of genes related to osteogenic differentiation is down-regulated,and the expression of adipogenic differentiation genes is up-regulated,resulting in insufficient bone formation.The activation of other immune-related subgroups promotes the maturation and differentiation of osteoclasts and enhances bone resorption.Conclusion: There are many cell subgroups in bone marrow mesenchymal stem cells,each of which expresses its own characteristic genes and performs different functions.The bone marrow mesenchymal stem cells of patients with osteoporosis have changed.First,their osteogenic subpopulations disappear,and osteoblast precursor cells are significantly reduced.Secondly,the tendency of osteogenic differentiation in the differentiated subpopulations is also greatly reduced.Accordingly,fat The trend of differentiation has increased,and the expression of immune-related genes in other subgroups responsible for immune regulation has been up-regulated,which promotes the activation of osteoclasts.Various factors jointly mediate the occurrence and development of osteoporosis.