PT -期刊文章盟莫龙卡梅拉AU - Smirnova, Natalia F. AU - Jeridi, Aicha AU - Kneidinger, Nikolaus AU - Hollauer, Christine AU - Schupp, Jonas Christian AU - Kaminski, Naftali AU - Jenne, Dieter AU - Eickelberg, Oliver AU - Yildirim, Ali Önder TI - Cathepsin B promotes collagen biosynthesis, which drives bronchiolitis obliterans syndrome AID - 10.1183/13993003.01416-2020 DP - 2021 May 01 TA - European Respiratory Journal PG - 2001416 VI - 57 IP - 5 4099 - //www.qdcxjkg.com/content/57/5/2001416.short 4100 - //www.qdcxjkg.com/content/57/5/2001416.full SO - Eur Respir J2021 May 01; 57 AB - Bronchiolitis obliterans syndrome (BOS) is a major complication after lung transplantation (LTx). BOS is characterised by massive peribronchial fibrosis, leading to air trapping-induced pulmonary dysfunction. Cathepsin B, a lysosomal cysteine protease, has been shown to enforce fibrotic pathways in several diseases. However, the relevance of cathepsin B in BOS progression has not yet been addressed. The aim of the study was to elucidate the function of cathepsin B in BOS pathogenesis.We determined cathepsin B levels in bronchoalveolar lavage fluid (BALF) and lung tissue from healthy donors (HD) and BOS LTx patients. Cathepsin B activity was assessed via a fluorescence resonance energy transfer-based assay and protein expression was determined using Western blotting, ELISA and immunostaining. To investigate the impact of cathepsin B in the pathophysiology of BOS, we used an in vivo orthotopic left LTx mouse model. Mechanistic studies were performed in vitro using macrophage and fibroblast cell lines.We found a significant increase of cathepsin B activity in BALF and lung tissue from BOS patients, as well as in our murine model of lymphocytic bronchiolitis. Moreover, cathepsin B activity was associated with increased biosynthesis of collagen and had a negative effect on lung function. We observed that cathepsin B was mainly expressed in macrophages that infiltrated areas characterised by a massive accumulation of collagen deposition. Mechanistically, macrophage-derived cathepsin B contributed to transforming growth factor-β1-dependent activation of fibroblasts, and its inhibition reversed the phenotype.Infiltrating macrophages release active cathepsin B, thereby promoting fibroblast activation and subsequent collagen deposition, which drive BOS. Cathepsin B represents a promising therapeutic target to prevent the progression of BOS.CatB is a new biomarker and therapeutic target for early bronchiolitis obliterans syndrome after lung transplantation https://bit.ly/36vOXHc