Drug Design, Development and Therapy (Dec 2023)
Linarin Protects Against CCl4-Induced Acute Liver Injury via Activating Autophagy and Inhibiting the Inflammatory Response: Involving the TLR4/MAPK/Nrf2 Pathway
Abstract
Lulu Li,1,2 Yan Lan,3 Fuqian Wang,1,2 Tiexiang Gao1 1Faculty of Pharmacy, Hubei University of Chinese Medicine, Wuhan, Hubei, People’s Republic of China; 2Department of Pharmacy, Wuhan NO.1 Hospital, Wuhan, Hubei, People’s Republic of China; 3Department of Pharmacy, Huangshi Central Hospital, Huangshi, Hubei, People’s Republic of ChinaCorrespondence: Tiexiang Gao, Faculty of Pharmacy, Hubei University of Chinese Medicine, No. 16 Huangjiahu West Road, Hongshan District, Wuhan, Hubei, 430065, People’s Republic of China, Email [email protected]: Linarin has been implicated in the inhibition of inflammatory responses and hepatoprotective effects. However, the precise mechanism by which Linarin integrates injury-induced signaling from inflammatory responses and oxidative stress remains unclear.Methods: We evaluated the role of Linarin in a mouse model of carbon tetrachloride (CCl4)-induced acute liver injury. Mice were orally pretreated with Linarin or vehicle for seven consecutive days, followed by intraperitoneal injection with 0.2% (v/v) CCl4. To investigate the mechanism of action on oxidative stress, CCl4-stimulated HepG2 cells were utilized.Results: Our results revealed Linarin remarkably attenuated the loss of hepatic architecture, inflammatory cell infiltration, serum transaminases, and pro-inflammatory cytokines induced by CCl4. Linarin attenuated CCl4-induced oxidative stress by increasing the expression of cytosolic Nrf2 (nuclear factor erythroid 2-related factor 2), inducing nuclear localization of Nrf2, and increasing stress-induced protein heme oxygenase-1 (HO-1). Additionally, Linarin decreased the expression of toll-like receptors (TLR)-4, and its downstream proteins, MyD88, IRAK1, and TRAF6. Furthermore, Linarin reversed CCl4-induced phosphorylation of ERK, p38, and JNK. Importantly, Linarin increased the expression of both LC3II and Beclin 1, which are hallmarks of autophagic flux. Autophagy-mediated hepatoprotective effects in Linarin-treated HepG2 cells were mitigated by the autophagy inhibitor 3-MA. However, combined treatment of Linarin with 3-MA failed to significantly reverse cell apoptosis and the production of transaminases and pro-inflammatory cytokines.Conclusion: Linarin prevents acute liver injury, possibly by alleviating ROS-induced oxidative stress, inhibiting TLR4/MyD88 and JNK/p38/ERK-mediated inflammatory responses, and promoting Beclin 1/LC3II-mediated autophagic flux.Keywords: Linarin, acute liver injury, autophagy, TLR4, MAPK, Nrf2
