Association of bone marrow mesenchymal stem cells and intracellular reactive oxygen species levels in patients with systemic lupus erythematosus / 中华风湿病学杂志

ABSTRACT

Objective To explore the role of intracellular reactive oxygen species (ROS) in the senescence of bone marrow mesenchymal stem cells(BMSCs)in patients with systemic lupus erythematosus(SLE) and the underlying mechanisms that controls the intracellular ROS levels in vitro. Methods Human bone marrow aspirates were collected from iliac of eight donors and eight SLE patients and cultured in vitro.Morphological appearance of BMSCs at different passages was examined by inverted microscope. Nuclear size was measured by fluorescence microscope. BMSCs were monitored using the senescence associated β-galacto-sidase (SAβ-gal) assay to characterize senescence in vitro. The quantification of intracellular ROS production was detected by flow cytometry. Real-time PCR technique was used to determine the gene expressions of PI3K, KRas, NRas and FoxO3 at transcription level. The expression of FoxO3, phospho-FoxO3 (p-FoxO3),AKT and phospho-AKT (p-AKT) protein were determined by Western blot analysis. Statistical analysis was conducted with t-test and Mann-Whitney rank test.Results There were no differences in morphology and nuclear size[(31.4±4.5) vs (28.2±4.8) μm, P=0.628] of BMSCs between SLE patients and normal controls.The percentage of SA β-gal positive BMSCs from SLE patients was higher than that from healthy controls [(31.8±9.0)% vs (12.4±0.7)%, P＜0.05]. Intracellular ROS levels of BMSCs from SLE patients increased more significantly than healthy donors in vitro (34600±9600 vs 17 958±5400, P＜0.05). No significant differences in the expression of PI3K, NRas, KRas and FoxO3 from SLE subjects were observed at mRNA levels compared with normal controls, though all showed a similar upward trend. The expression of p-FoxO3 and p-AKT of BMSCs from SLE patients increased significantly compared with healthy controls at protein levels.Conclusion These data suggest that BMSCs from SLE patients aged more quickly, with high SA β-gal activity and up-regulation of intracellular ROS, which is associated with up-regulation of p-FoxO3 and pAKT at protein levels. These results indicate that bone marrow mesenchymal cell senescence may be associated with the pathogcnesis of SLE by maintaining the lifespan of BMSCs.