1,8-Cineole improves hepatic fibrosis by inhibiting HIF-1α/BNIP3/PINK1/Parkin-dependent mitophagy signaling and inducing apoptosis in activated hepatic stellate cells

Aim The HIF-1α/BNIP3/mitophagy signaling pathway might be closely associated with hepatic fibrosis. Although 1,8-cineole (CIN) has been shown to improve fibrosis in several organs, direct evidence for its anti-hepatic fibrotic effects remains lacking. The objective of this study was to confirm the role of mitophagy in hepatic stellate cells (HSCs) and the role of the HIF-1α/BNIP3 signaling pathway in the pathogenesis of hepatic fibrosis. Additionally, in vivo and in vitro experiments were conducted to explore the effect of CIN on hepatic fibrosis. Methods In a CCl 4 -induced hepatic fibrosis rat model and in CoCl 2 -treated HSCs, expression level of HIF-1α, BNIP3, α-SMA, collagen 1, PINK1, Parkin, p62 and LC3-II/LC3-I were examined, and the ubiquitinated Parkin level was detected following immunoprecipitation. In addition, the proliferation and apoptosis of HSCs were detected. Results Our findings indicated that CIN significantly mitigated CCl 4 -induced hepatic fibrosis. The alleviation of hepatic fibrosis after CIN treatment was associated with a markedly decrease in HIF-1α, BNIP3, α-SMA, collagen 1, PINK1, Parkin and LC3-II/LC-I, as well as a signally increase in P62. Moreover, CIN, Mdivi-1 (mitophagy inhibitor) and Bafilomycin A1 (lysosomal inhibitors) significantly inhibited the proliferation of HSCs. The ubiquitinated Parkin level was significantly more prominent in the CoCl 2 group, while the ubiquitinated Parkin level was observably decreased after CIN treatment. Additionally, CIN exhibited efficacy comparable to that of TRAIL (apoptosis-inducing agent) in significantly promoting apoptosis in hepatic stellate cells. Conclusion CIN improves hepatic fibrosis by inhibiting HIF-1α/BNIP3/PINK1/Parkin-dependent mitophagy signaling and inducing apoptosis in activated HSCs.