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

Figure 5

Overexpression of CARM1 led to senescence resistance through DDR2. (a) Overexpression of CARM1 led to a significant upregulation in both DDR2 and TERT expressions but had no effect on p16 expression. Simultaneous inhibition of DDR2 with CARM1 overexpression increased the mRNA level of p16. (b) Although overexpression of DDR2 alone had no effect on the expression of CARM1 or p16, simultaneous inhibition of CARM1 with DDR2 overexpression significantly increased the mRNA level of p16. (c) Western blot analysis confirmed that overexpression of CARM1 increased the protein and phosphorylation level of DDR2, whereas overexpression of DDR2 had no effect on the protein level of CARM1. (d) However, overexpression of either CARM1 or DDR2 in hBM-MSCs altered their proliferation rate, as determined by growth curve and EdU incorporation assays. (e) In contrast, when CARM1 or DDR2 was overexpressed, the percentage of cells positive for the senescence marker β-Gal decreased significantly after 1 week of in vitro culture. For WB assays, the relative expression of phosphorylated DDR2 and total DDR2 refers to β-actin that was determined using density analysis, and the ratios were shown above the bands. Bars represent the standard error of the from three repeats. Statistical significance was determined by ANOVA and Student’s -test. , .

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