title: Nrf2 Activation Is Required for Ligustrazine to Inhibit Hepatic Steatosis in Alcohol-Preferring Mice and Hepatocytes.
abstract: Hepatic steatosis is the most distinctive feature of alcoholic liver disease (ALD). Our previous in vivo study showed that ligustrazine, a major active alkaloid isolated from Ligusticum chuanxiong Hort, attenuated alcohol-induced hepatic steatosis and in vitro study revealed that nuclear factor (erythroid-derived 2)-like 2 (Nrf2) activation might be a prerequisite. This study was aimed to explore the in vivo function of Nrf2 in the protective effect of ligustrazine and illustrate downstream mechanisms. Nrf2 shRNA lentivirus was introduced to establish Nrf2-knockdown mice. Results showed that Nrf2 knockdown aggravated alcoholic liver injury and abolished the protective effect of ligustrazine, evidenced by elevated serum biomarkers and severe liver inflammation. Ligustrazine impressively ameliorated hepatic steatosis through inhibiting hepatic sterol regulatory element-binding protein-1c and inducing peroxisome proliferator-activated receptor-alpha, which was abrogated by Nrf2 knockdown. Noteworthily, Nrf2 knockdown apparently reinforced the inductive effect of alcohol on hypoxia-inducible factor 1-alpha (HIF-1α). Ligustrazine weakened the stimulation of alcohol on HIF-1α expression, which was abrogated by Nrf2 shRNA lentivirus. Consistent results were obtained from in vitro study, implying that Nrf2/HIF-1α pathway participated in the modulation of ligustrazine. Gain- or loss-of-function analyses further revealed that Nrf2 siRNA and dimethyloxalylglycine, a HIF-1α agonist, abolished the inhibitory effect of ligustrazine, whereas HIF-1α siRNA mimicked the role of ligustrazine and even rescued the inhibitory effect of ligustrazine on ethanol-induced lipid accumulation in Nrf2-knockdown hepatocytes. Taken together, we concluded that ligustrazine attenuated alcohol-induced hepatic steatosis via a Nrf2/HIF-1α pathway-dependent mechanism.
authors.affiliation: Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China.
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Lu
authors.affiliation: Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China.
authors.forename: Wenxuan
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China.
authors.forename: Jiangjuan
authors.initials: J
authors.lastname: Shao
authors.affiliation: Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Department of Pathology, School of Medicine, Saint Louis University, St Louis, Missouri.
authors.forename: Anping
authors.initials: A
authors.lastname: Chen
authors.affiliation: Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China; nytws@163.com.|Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China.
authors.forename: Shizhong
authors.initials: S
authors.lastname: Zheng
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D000431:Ethanol / Q000009:adverse effects; D005235:Fatty Liver, Alcoholic / Q000188:drug therapy* / Q000378:metabolism; D055785:Gene Knockdown Techniques; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D050356:Lipid Metabolism; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D011719:Pyrazines / Q000627:therapeutic use*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D011719:Pyrazines; D000431:Ethanol; C017953:tetramethylpyrazine
keywords: alcoholic liver disease; hepatic steatosis; hypoxia-inducible factor 1-alpha; ligustrazine; nuclear factor (erythroid-derived 2)-like 2