Background and Purpose Idiopathic pulmonary fibrosis is a progressive fatal disease characterized by interstitial remodeling, with high lethality and a lack of effective medical therapies. Tetrandrine has been proposed to present anti-fibrotic effects, but the efficacy and mechanisms of tetrandrine against lung fibrosis has not been systematically evaluated. We sought to study the potential therapeutic effects and mechanisms of tetrandrine in lung fibrosis. Experimental Approach The anti-fibrotic effects of tetrandrine were evaluated in bleomycin-induced mouse models and TGF-β1-stimulated murine lung fibroblasts. We performed Chromatin Immunoprecipitation (ChIP), Immunoprecipitation (IP) and mRFP-GFP-MAP1LC3B adenovirus construct to investigate the novel mechanisms of tetrandrine-induced autophagy. Key Results Tetrandrine decreased TGF-β1-induced expression of α-smooth muscle actin, fibronectin, vimentin and type 1 collagen and proliferation in fibroblasts. Tetrandrine restored TGF-β1-induced impaired autophagy, accompanied by the up-regulation and enhanced interaction of SQSTM1 and MAP1LC3-Ⅱ. ChIP studies revealed that NRF2 bound to SQSTM1 promoter in tetrandrine-induced autophagy. Furthermore, TGF-β1-induced phosphorylated mTOR was inhibited by tetrandrine, with reduced activation levels of Rheb. In vivo tetrandrine suppressed the bleomycin-induced expression of fibrotic markers and improved pulmonary function. Conclusion and Implications Our data suggest that tetrandrine might be recognized as a novel autophagy inducer, thus attenuating lung fibrosis. Tetrandrine should be investigated as a novel therapeutic strategy for IPF.

Abstract Background: Thymic stromal lymphopoietin (TSLP) is present in two distinct isoforms, short-form (sfTSLP) and long-form (lfTSLP). lfTSLP promotes inflammation while sfTSLP inhibits inflammation in allergic asthma. However, little is known about the regulation of lfTSLP and sfTSLP during allergic attack in asthma airway epithelium. Methods and Results: Here, we report that SUMOylation was enhanced in HDM-induced allergic asthma airway epithelium. Inhibition of SUMOylation significantly alleviated airway Th2 inflammation and lfTSLP expression. Mechanistically, CBX4, a SUMOylation E3 ligase, enhanced lfTSLP, but not sfTSLP, mRNA translation through the RNA binding protein, MEX-3B. MEX-3B promoted lfTSLP translation through binding of its KH domains to the lfTSLP mRNA. Furthermore, CBX4 regulated MEX-3B transcription in HBE through enhancing SUMOylation levels of the transcription factor, TFII-I. Conclusion: We demonstrate an important mechanism whereby CBX4 promotes MEX-3B transcription through enhancing TFII-I SUMOylation, and MEX-3B enhances the expression of lfTSLP through binding to the lfTSLP mRNA and promoting its translation. Our findings uncover a novel target of CBX4 for therapeutic agents to lfTSLP-mediated asthma.

Background and Purpose Idiopathic pulmonary fibrosis is a progressive fatal disease characterized by interstitial remodeling, with high lethality and a lack of effective medical therapies. Tetrandrine has been proposed to present anti-fibrotic effects, but the efficacy and mechanisms of tetrandrine against lung fibrosis has not been systematically evaluated. We sought to study the potential therapeutic effects and mechanisms of tetrandrine in lung fibrosis. Experimental Approach The anti-fibrotic effects of tetrandrine were evaluated in bleomycin-induced mouse models and TGF-β1-stimulated murine lung fibroblasts. We performed Chromatin Immunoprecipitation (ChIP), Immunoprecipitation (IP) and mRFP-GFP-MAP1LC3B adenovirus construct to investigate the novel mechanisms of tetrandrine-induced autophagy. Key Results Tetrandrine decreased TGF-β1-induced expression of α-smooth muscle actin, fibronectin, vimentin and type 1 collagen and proliferation in fibroblasts. Tetrandrine restored TGF-β1-induced impaired autophagy, accompanied by the up-regulation and enhanced interaction of SQSTM1 and MAP1LC3-Ⅱ. ChIP studies revealed that NRF2 bound to SQSTM1 promoter in tetrandrine-induced autophagy. Furthermore, TGF-β1-induced phosphorylated mTOR was inhibited by tetrandrine, with reduced activation levels of Rheb. In vivo tetrandrine suppressed the bleomycin-induced expression of fibrotic markers and improved pulmonary function. Conclusion and Implications Our data suggest that tetrandrine might be recognized as a novel autophagy inducer, thus attenuating lung fibrosis. Tetrandrine should be investigated as a novel therapeutic strategy for IPF.