Histone Arginine Methylation-Mediated Epigenetic Regulation of Discoidin Domain Receptor 2 Controls the Senescence of Human Bone Marrow Mesenchymal Stem Cells

Figure 1

hBM-MSCs exhibited phenotypical changes associated with cellular senescence after prolonged in vitro culture. (a) Compared with early-passage cells, the late-passage hBM-MSCs showed elongated cellular processes, reduced clone number, and increased cell area. (b) The growth curve showed that the doubling time of late-passage cells was extended compared to that of early-passage cells. (c) EdU cell proliferation assay showed a marked reduction in EdU-positive cell nuclei among the late-passage cells, suggesting a decrease in cell proliferation capacity. (d) qPCR analysis of the cyclin-dependent kinase (CDK) inhibitors (CKI) demonstrated a significant increase in p16 and p15 expression levels in the late-passage cells (passage 7). (e) The expression of the senescence-associated marker β-Gal was also markedly increased in late-passage cells. (f) Immunofluorescence staining showed increased endogenous levels of histone H2A.X protein with Ser139 phosphorylation (H2A.X Ser139) in late-passage cells. Bars represent the standard error of the from three repeats. Statistical significance was determined by ANOVA and Student’s -test. , .

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