title: Gallic acid induces necroptosis via TNF-α signaling pathway in activated hepatic stellate cells.
abstract: Gallic acid (3, 4, 5-trihydroxybenzoic acid, GA), a natural phenolic acid widely found in gallnuts, tea leaves and various fruits, possesses several bioactivities against inflammation, oxidation, and carcinogenicity. The beneficial effect of GA on the reduction of animal hepatofibrosis has been indicated due to its antioxidative property. However, the cytotoxicity of GA autoxidation causing cell death has also been reported. Herein, we postulated that GA might target activated hepatic stellate cells (aHSCs), the cell type responsible for hepatofibrosis, to mitigate the process of fibrosis. The molecular cytotoxic mechanisms that GA exerted on aHSCs were then analyzed. The results indicated that GA elicited aHSC programmed cell death through TNF-α-mediated necroptosis. GA induced significant oxidative stress through the suppression of catalase activity and the depletion of glutathione (GSH). Elevated oxidative stress triggered the production of TNF-α facilitating the undergoing of necroptosis through the up-regulation of key necroptotic regulatory proteins TRADD and receptor-interacting protein 3 (RIP3), and the inactivation of caspase-8. Calmodulin and calpain-1 activation were engaged, which promoted subsequent lysosomal membrane permeabilization (LMP). The TNF-α antagonist (SPD-304) and the RIP1 inhibitor (necrostatin-1, Nec-1) confirmed GA-induced TNFR1-mediated necroptosis. The inhibition of RIP1 by Nec-1 diverted the cell death from necroptosis to apoptosis, as the activation of caspase 3 and the increase of cytochrome c. Collectively, this is the first report indicating that GA induces TNF signaling-triggered necroptosis in aHSCs, which may offer an alternative strategy for the amelioration of liver fibrosis.
authors: Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan.
authors: Ya Ju
authors: YJ
authors: Chang
authors: Department of Education and Research, Taichung Veterans General Hospital, Taichung, Taiwan.
authors: Shih Lan
authors: SL
authors: Hsu
authors: Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan.
authors: Yi Ting
authors: YT
authors: Liu
authors: Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan.
authors: Yu Hsuan
authors: YH
authors: Lin
authors: Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan.
authors: Ming Hui
authors: MH
authors: Lin
authors: Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan.
authors: Shu Jung
authors: SJ
authors: Huang
authors: Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan.
authors: Ja-an Annie
authors: JA
authors: Ho
authors: Department of Applied Chemistry, National Chi Nan University, Puli, Taiwan.
authors: Li-Chen
authors: LC
authors: Wu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle; D049109:Cell Proliferation; D002478:Cells, Cultured; D002839:Chromans / Q000494:pharmacology; D005707:Gallic Acid / Q000494:pharmacology*; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D007211:Indoles / Q000494:pharmacology; D015227:Lipid Peroxidation; D009336:Necrosis / Q000139:chemically induced*; D018384:Oxidative Stress; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D002839:Chromans; D007211:Indoles; D017382:Reactive Oxygen Species; D047888:Receptors, Tumor Necrosis Factor, Type I; C527814:SPD-304; C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha; D005707:Gallic Acid; D017346:Protein Serine-Threonine Kinases; C586536:RIPK1 protein, rat; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D020169:Caspases