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

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 TGF{beta}. 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 2nd 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 TGF{beta}, as reflected by a reduction in the TGF{beta} 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 TGF{beta}. Based on the interactome, Integrin{beta}3 seems to be a major player in integration of TGF{beta} 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.