HMGB1-induced fibroblast transdifferentiation depends on HPSE activity. MRC-5 cells were cultured with recombinant HMGB1 (100 ng/ml) or OGT2115 (0.5 µM) for 24 hours and then subjected to following analysis. A. Western blot results for analysis of HMGB1-induced α-SMA and collagen I expression. B. HMGB1 stimulated MRC-5 cells expression of significantly higher levels of active and latent HPSE. C. Real-time PCR for analysis of the HPSE mRNA levels after HMGB1 stimulation. D. Addition of OGT2115, an HPSE inhibitor, attenuated HMGB1 induced α-SMA and collagen I expression. *, p < 0.05; **, p < 0.01; and ***, p < 0.001.