Attenuation of Pulmonary Fibrosis by the MyD88 Inhibitor TJ-M2010-5 Through Autophagy Induction in Mice.

Background and Objectives: Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease with few effective treatments. In its pathogenesis, damage-associated molecular patterns are released and recognized by Toll-like receptors (TLRs); all TLRs except TLR3 transduce signals through MyD88. Research has shown that autophagy participates in the progression of pulmonary fibrosis, and MyD88 is closely associated with autophagy. However, whether targeting MyD88 can affect fibrosis progression by regulating autophagy during lung fibrosis remains unclear. Materials and Methods: TJ-M2010-5 (TJ-5) is a small molecular derivative of aminothiazole that inhibits MyD88 homodimerization. A bleomycin-induced pulmonary fibrosis model in mice was established, and a human lung fibroblast cell line MRC-5 was cultured, and the mechanism of fibrosis induced by TGF-β1 was studied. TJ-5 and the autophagy inhibitor 3-MA were used to intervene. Results: Our study indicated that TJ-5 suppressed fibrosis foci formation and collagen deposition in fibrotic lungs, effectively increased the survival rate of bleomycin-stimulated mice from 40.0% to 80.0%, and repressed lung fibroblast activation in vitro. Subsequently, TJ-5 could trigger autophagy, as indicated by increased autophagosomes, LC3B-II and Beclin-1 promotion, and p62 degradation. Moreover, inhibition of TJ-5-induced autophagy by 3-MA reversed the anti-fibrosis effect of TJ-5. Furthermore, the autophagy-related pathways PI3K/AKT/mTOR and MAPK/mTOR were inhibited under TJ-5 intervention. Conclusions: Our findings demonstrated that the mechanism of TJ-5 in alleviating lung fibrosis was through triggering MyD88-related autophagy, and TJ-5 may be therapeutically useful for the clinical treatment of IPF.