Fig. 5

Celastrol (Cel) suppresses the enzymatic activity of pyruvate kinase and the proinflammatory activity of HMGB1. a Western blotting against PKM1 and PKM2 in macrophages treated or not with Cel at 0.25, 0.5 or 1.0 μmol/L. The corresponding densitometry is shown (n = 3). b Catalytic activity of pyruvate kinase with or without Cel treatment at 10, 20 and 40 μmol/L, n = 3, *P < 0.05, **P < 0.01, ***P < 0.001 vs. DMSO. c The contribution of HMGB1 to IL-1β expression, as determined by Western blotting. Assays were set up with HMGB1 at 0.8 μg/ml; B box, 0.8 μg/ml; and Cel, 0.2 μmol/L (n = 3). ^#P < 0.05 vs. DMSO; *P < 0.05, **P < 0.01 vs. HMGB1 or B box. d Secretion of HMGB1 from macrophages treated or not with Cel at 0.25, 0.5 or 1.0 μmol/L, as determined using Western blotting (n = 3). ^#P < 0.05 vs. DMSO. e Immunofluorescence staining with antibody against HMGB1 (green) or a dye targeting the cell membrane (red). Scale bar = 6 μm. LPS lipopolysaccharide, PKM2 pyruvate kinase M2, PKM1 pyruvate kinase M1, HMGB1 high mobility group box 1, IL-1β interleukin-1β