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Prevention of free fatty acid–induced hepatic lipotoxicity by 18β‐glycyrrhetinic acid through lysosomal and mitochondrial pathways
Author(s) -
Wu Xudong,
Zhang Luyong,
Gurley Emily,
Studer Elaine,
Shang Jing,
Wang Tao,
Wang Cuifen,
Yan Ming,
Jiang Zhenzhou,
Hylemon Phillip B.,
Sanyal Arun J.,
Pandak William M.,
Zhou Huiping
Publication year - 2008
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.22239
Subject(s) - lipotoxicity , nonalcoholic fatty liver disease , liver injury , endocrinology , medicine , oxidative stress , pharmacology , steatosis , cathepsin b , fatty liver , biology , hepatic stellate cell , chemistry , biochemistry , insulin resistance , enzyme , insulin , disease
Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and affects millions of people worldwide. Despite the increasing prevalence of NAFLD, the exact molecular/cellular mechanisms remain obscure and effective therapeutic strategies are still limited. It is well‐accepted that free fatty acid (FFA)‐induced lipotoxicity plays a pivotal role in the pathogenesis of NAFLD. Inhibition of FFA‐associated hepatic toxicity represents a potential therapeutic strategy. Glycyrrhizin (GL), the major bioactive component of licorice root extract, has a variety of pharmacological properties including anti‐inflammatory, antioxidant, and immune‐modulating activities. GL has been used to treat hepatitis to reduce liver inflammation and hepatic injury; however, the mechanism underlying the antihepatic injury property of GL is still poorly understood. In this report, we provide evidence that 18 β‐glycyrrhetinic acid (GA), the biologically active metabolite of GL, prevented FFA‐induced lipid accumulation and cell apoptosis in in vitro HepG2 (human liver cell line) NAFLD models. GA also prevented high fat diet (HFD)‐induced hepatic lipotoxicity and liver injury in in vivo rat NAFLD models. GA was found to stabilize lysosomal membranes, inhibit cathepsin B expression and enzyme activity, inhibit mitochondrial cytochrome c release, and reduce FFA‐induced oxidative stress. These characteristics may represent major cellular mechanisms, which account for its protective effects on FFA/HFD‐induced hepatic lipotoxicity. Conclusion: GA significantly reduced FFA/HFD‐induced hepatic lipotoxicity by stabilizing the integrity of lysosomes and mitochondria and inhibiting cathepsin B expression and enzyme activity. (H EPATOLOGY 2008.)