Figure 2

LPS-induced autophagy is decreased in ASMSCs compared with that in HDMSCs. (a) MSCs were treated with LPS (5 μg ml⁻¹) for 0–24 h. The expression levels of LC3-II were lower in ASMSCs (n=30) than in HDMSCs (n=30) after LPS stimulation for 4, 8 and 16 h. The expression pattern of P62 was opposite to that of LC3-II: P62 expression was higher in ASMSCs (n=30) than in HDMSCs (n=30) after LPS stimulation for 4, 8 or 16 h. (b) MSCs were treated with different concentrations (1–20 μg ml⁻¹) of LPS for 8 h. The expression of LC3-II was lower in ASMSCs (n=30) than in HDMSCs (n=30) in the presence of LPS at concentrations from 2 to 20 μg ml⁻¹, and the expression of P62 was higher in ASMSCs (n=30) than in HDMSCs (n=30) at LPS concentrations from 2 to 20 μg ml⁻¹. (c) MSCs were transfected with GFP-LC3B and treated with LPS (5 μg ml⁻¹) for 8 h. Autophagosome formation was indicated by GFP-labeled punctate. Fluorescence microscopy (× 400, scale bar=20 μm) revealed a markedly strong and punctate pattern of GFP-LC3B expression in HDMSCs (n=30) but much weaker and more diffuse GFP-LC3B expression in ASMSCs (n=30). The quantitative results are presented at right. The figures in a, b are typical examples of MSCs from one healthy donor and one AS subject. The values in a, b are presented as the means±s.d.; *P<0.05. AS, ankylosing spondylitis; ASMSCs, ankylosing spondylitis mesenchymal stem cells; HDMSCs, healthy donors mesenchymal stem cells; LPS, lipopolysaccharide; MSCs, mesenchymal stem cells.