ABSTRACT
Objective To evaluate biological behaviors of bone marrow mesenchymal stem cells (BMSCs) from patients with systemic lupus erythematosus (SLE),to confirm that the BMSCs are aging stems cells,and to explore mechanisms underlying their aging.Methods BMSCs were isolated from bone marrow of 6 patients with SLE (patient group) and 8 healthy human controls (control group) by density-gradient centrifugation and plastic adherence,and cultured in vitro.Optical microscopy was conducted to observe morphological changes and growth of BMSCs,and growth curves were drawn.The differentiation ability of BMSCs was evaluated through culture of them with adipogenic and osteogenic induction medium.Flow cytometry was performed to identify cellular surface markers and to analyze cell cycle and apoptosis,and scratch assay to assess the migration ability of BMSCs.Immunofluorcscence assay and Western blot analysis were carried out to analyze the distribution and expression of p27kip1/PTEN in BMSCs respectively.Results Patient-derived BMSCs,which had a broad,fiat and polygonal shape,showed decreased growth rate,migration activity as well as adipogenic and osteogenic ability compared with those from the controls.There was a significant increase in the proportion of BMSCs in early stage (17.98％ ± 3.26％ vs.8.23％ ± 3.25％,t =3.91,P =0.011) as well as in middle to late stages (16.80％ ± 9.63％ vs.3.33％ ± 2.21％,t =2.99,P=0.048) of apoptosis in the patient group compared with the control group.Moreover,compared with the control group,the patient group showed a significantly higher proportion of BMSCs arrested in the G0/G1 phase (92.34％ ± 5.80％ vs.78.65％ ± 3.22％,t =3.635,P =0.015),but a lower proportion in the S phase (0.86％ ± 1.72％ vs.5.06％ ± 1.874％,t =3.084,P=0.027).The protein expressions of p27 and PTEN were significantly higher in the patient group than in the control group (p27/β-actin:t =2.784,P=0.039;PTEN/β-actin:t=4.812,P =0.041).Conclusion The BMSCs from SLE patients exhibit senescence-related features,which may be associated with elevated expression levels of p27kip1/PTEN.