p53/p21 Pathway Involved in Mediating Cellular Senescence of Bone Marrow-Derived Mesenchymal Stem Cells from Systemic Lupus Erythematosus Patients
Figure 1
BM-MSCs from SLE patients are aging cells. (a) At p3, the morphology of normal BM-MSCs showed homogeneous spindle-shaped fibroblast-like growth. However, BM-MSCs from SLE patients appeared bigger in size and flattened in appearance. (b) Growth curve of BM-MSCs was tested by cell counting assay. The absorbance was shown as the proliferation rate. BM-MSCs from SLE patients grew more slowly than those from the control group. Each point represents quantities relative to the normal group at Day 1 (*). ((c)-(d)) Counted colonies of BM-MSCs from SLE patients and normal control were plated at a density of 25 cells = cm2 for 15 days in culture, stained with 1% crystal violet. Each bar represents quantities relative to BM-MSCs from Nor group and is mean ± SD of three experiments (*). ((e)-(f)) SA-β-gal was used to examine BM-MSCs senescence. BM-MSCs from SLE patients and normal control were performed SA-β-Gal staining. The number of SA-β-gal-positive cells obviously increased in BM-MSCs from SLE patients compared with those of normal control. Each bar represents quantities relative to BM-MSCs from Nor group and is mean ± SD of three experiments (*). (g) After cells culture, cells were removed from the culture dish with trypsin/EDTA at p3, fixed, stained for DNA with PI, and analyzed by flow cytometry (-axis, cell count; -axis, DNA content). (h) Mitotic indices of BM-MSCs from control group and SLE patients. Graphs in (h) represent DNA content indicating the percentages of cells in G0/G1, S, and G2/M phases of the cell cycle. The data are obtained from staining the DNA of ASCs from normal group and SLE patients. A decrease in the percentage of cells in S phases was seen in SLE patients, while an increase in percentage of cells in G0/G1 phase was seen in SLE patients. Each bar represents quantities relative to BM-MSCs from Nor group and is mean ± SD of three experiments (*) (#). Following the cell cycle progression, these cells showed a greater fraction in quiescent of G0/G1 phase in SLE patients when compared with normal control.
