Abstract

N-glycosylation, the predominant post-translational protein modification, significantly influences protein physicochemical properties and biological functions. Kifunensine, a N-glycosylation inhibitor, shows promise as a potential therapeutic agent for modulating the hyperactivation of transforming growth factor-beta 1 signalling pathways in fibrotic diseases. This study explored kifunensine's effects and mechanisms of action using an innovative in vitro cardiac fibrosis model involving primary rat cardiac fibroblasts treated with transforming growth factor-beta 1. Protein expression related to cardiac fibrosis was assessed via Western blotting and immunofluorescence assays. Kifunensine significantly protected these cells against transforming growth factor-beta 1 induced fibrosis, as indicated by decreased collagen I, collagen III, and alpha-smooth muscle actin expression. Interestingly, kifunensine did not alter transforming growth factor-beta receptor expression but reduced transforming growth factor-beta 1 ligand-receptor complex formation, inhibiting transforming growth factor-beta type I receptor and transforming growth factor-beta type II receptor activation and suppressing suppressor of mothers against decapentaplegic 2 and suppressor of mothers against decapentaplegic 3 phosphorylation. This underlines N-glycosylation's role in cardiac fibrosis and establishes the anti-fibrotic potential of moderate N-glycan alteration on transforming growth factor-beta receptors using kifunensine, suggesting a novel therapeutic strategy for myocardial fibrosis.