7-Hydroxy-3-(4'-methoxyphenyl) coumarin (C12) attenuates bleomycin-induced acute lung injury and fibrosis through activation of SIRT3.

Silent mating-type information regulation 2 homology 3 (SIRT3) is a member of the sirtuins family expressed in mitochondria performs deacetylation of metabolic enzymes and promotes longevity. 7-hydroxy-3-(4'-methoxyphenyl) coumarin (C12) is a small molecule first ever known for its direct activation of SIRT3. SIRT3 performs its function by balancing the redox system by activating manganese superoxide dismutase (MnSOD) and 8-Oxoguanine glycosylase (OGG1). For the first time, we reported that activation of SIRT3 by C12 attenuated bleomycin (BLM)-)-induced acute lung injury and pulmonary fibrosis. C12 prevented the oxidative stress and injury caused by BLM in alveolar epithelial cells (BEAS-2B) in in vitro and inhibited the fibrosis in transforming growth factor-beta (TGF-β) induced fibrosis in fibroblasts (MRC-5). Additionally, activation of SIRT3 by C12 in vivo mice model alleviated BLM-induced inflammation, collagen accumulation, cellular infiltration, and restoration of alveolar architecture by inhibiting TGF-β, smooth muscle actin (α-SMA), collagen-1A, collagen-3A, and mesenchymal markers. The protective effect of C12 was through activation of MnSOD and OGG1 in both in vitro and in vivo models suggesting C12 can be a potent SIRT3 activator and helps to treat fibrotic-related diseases.