Chromone scaffold–mediated reprogramming of the epithelial–mesenchymal transition prevents fibrosis

Summary Fibrotic diseases are major causes of morbidity and mortality, and the epithelial–mesenchymal transition (EMT) plays a central role in the development of tissue/organ fibrosis. We discovered that eupatilin, a member of the chromone scaffold (CS)-containing compounds found ubiquitously in the plant kingdom, completely reversed fibrogenesis in vitro and substantially ameliorated bleomycin-induced lung fibrosis (BILF). Furthermore, eupatilin-induced growth arrest and morphological changes in primary fibroblasts derived from a patient with idiopathic pulmonary fibrosis (IPF). To better understand fibrosis, we established a mouse hepatic stellate cell (HSC) line that was robustly differentiated into myofibroblasts upon treatment with TGFβ. HSC-derived fibrogenesis was completely blocked by eupatilin, which caused dramatic morphological changes while inhibiting expression of EMT-related genes. The chemical groups linked to the 2 nd carbon (C2), C3, C6, and C7 on the CS of eupatilin were essential for its anti-fibrogenic effects. Unlike eupatilin, pirfenidone failed to block HSC fibrogenesis and did not affect the morphology of HSCs or lung fibroblasts. Although pirfenidone affected local production of TGFβ, as reflected by a reduction in the TGFβ level in lung lysates of BILF model mice, eupatilin is likely to act via a different therapeutic mechanism. In particular, eupatilin had greater anti-fibrotic capacity and EMT-inhibitory activity and significantly attenuated the phosphorylation of Erk by TGFβ. Based on the interactome, Integrinβ3 seems to be a major player in integration of TGFβ signaling into the eupatilin-mediated anti-fibrosis. Our findings suggest that combinatorial use of eupatilin and pirfenidone may augment the therapeutic efficacy of IPF treatment.