Reversal of Myofibroblast Apoptosis Resistance and Collagen Deposition by Phaseoloidin-Induced Autophagy Attenuates Pulmonary Fibrosis.

Background and Objectives: Myofibroblast apoptosis resistance and excessive extracellular matrix (ECM) deposition are central drivers of the irreversibility of pulmonary fibrosis, and both are mechanistically linked to autophagy impairment. Phaseoloidin is a bioactive compound derived from Entada phaseoloides. This study aimed to investigate the therapeutic potential of Phaseoloidin in bleomycin-induced pulmonary fibrosis and its underlying mechanisms. Methods:In vivo, the antifibrotic effects of Phaseoloidin were evaluated using a bleomycin-induced pulmonary fibrosis mouse model in male C57/BL mice. To further elucidate the mechanisms by which Phaseoloidin counteracts fibrosis, in vitro experiments were conducted using primary lung fibroblasts. Results: In vitro experiments showed that Phaseoloidin could activate the AMPK/mTOR pathway in autophagy-deficient myofibroblasts, effectively reversing autophagic defects and promoting collagen degradation. This autophagy activation selectively degraded PTPN13, a negative regulator of apoptosis, thereby enhancing the sensitivity of myofibroblasts to FasL-induced apoptosis and further facilitating fibrosis resolution. After AMPK gene knockout, the pro-autophagic effect of Phaseoloidin completely disappeared, and both collagen clearance and apoptosis recovery were blocked. In vivo experiments confirmed that Phaseoloidin exerted antifibrotic effects by activating AMPK-mediated autophagy in myofibroblasts, which significantly ameliorated pulmonary fibrosis. Conclusions: Phaseoloidin exerts a dual mechanism by activating AMPK-mediated autophagy in myofibroblasts: first, degrading PTPN13 to reverse myofibroblast apoptosis resistance; second, enhancing ECM turnover. These findings indicate that Phaseoloidin is a promising novel therapeutic candidate for pulmonary fibrosis.