小檗胺通过激活 AMPK 调节 mTOR/SREBP-1c 轴和 Nrf2/ARE 通路减轻脂肪变性 HepG2 细胞的脂质积累和氧化应激。
Berbamine induced AMPK activation regulates mTOR/SREBP-1c axis and Nrf2/ARE pathway to allay lipid accumulation and oxidative stress in steatotic HepG2 cells.
机构信息
Herbal Research Laboratory, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhawan 31, Post Box No. 80, Mahatma Gandhi Marg, Lucknow, 226001, India; Department of Biochemistry, University of Lucknow, Lucknow, 226007, India.
Herbal Research Laboratory, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhawan 31, Post Box No. 80, Mahatma Gandhi Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
出版信息
Eur J Pharmacol. 2020 Sep 5;882:173244. doi: 10.1016/j.ejphar.2020.173244. Epub 2020 Jun 8.
Non-alcoholic fatty liver disease is emanating as a global cataclysm. This study was designed to investigate the antioxidative, anti-inflammatory and fat metabolism-regulating potential of berbamine (BBM), a natural bis-benzylisoquinoline alkaloid. BBM attenuated intracellular lipid accumulation in oleic-acid exposed HepG2 cells (0.5 mM) by inhibiting fatty acid uptake, lipogenesis, and promoting fatty acid β-oxidation by activating AMP-activated kinase (AMPK) and peroxisome proliferator-activated receptor (PPAR)-α. Berbamine (5 μM) induced AMPK activation (P < 0.001) via LKB1 (Ser-428) and elevated AMP:ATP ratio (P < 0.001). AMPK activation negatively regulated mTOR and also constrained the nuclear translocation of SREBP-1c and inhibited the lipogenic proteins, stearoyl-CoA desaturase-1 (SCD-1) and fatty acid synthase (FAS) (P < 0.001). BBM stimulated nuclear translocation of redox-sensitive nuclear factor erythroid-2-related factor-2 (Nrf2) and increased hepatic expression of Nrf2 responsive enzymes, HO-1 and Nqo-1. BBM treatment reduced the oxidative burst and pro-inflammatory responses by significantly enhancing hepatic antioxidant defenses [SOD (P < 0.001), catalase (P < 0.001) and cellular glutathione (P < 0.01)] and diminishing NF-κB regulated pro-inflammatory cytokines (TNF-α, and IL-6) levels respectively. TEM analysis confirmed the disruption of mitochondrial structure and reduction in mitochondrial size (50.97%, P < 0.001) in steatotic HepG2 cells which was significantly prevented by 5 μM BBM treatment (71.84% as compared to control, P < 0.01). Pre-treatment of Compound C (AMPK inhibitor, 25 μM) greatly repressed the anti-steatotic properties exhibited by BBM confirming the involvement of AMPK signaling pathway. In summary, the results manifest that BBM reduces intracellular lipid accumulation via AMPK/mTOR/SREBP-1c axis mediated regulation of lipid metabolism and upsurged nuclear stability of Nrf2 by promoting AMPK/Nrf2 association to ameliorate oxidative stress/proinflammatory response.
非酒精性脂肪性肝病正在成为全球性灾难。本研究旨在探究小檗胺（BBM）作为一种天然双苄基异喹啉生物碱，其抗氧化、抗炎和调节脂肪代谢的潜力。BBM 通过抑制脂肪酸摄取、脂肪生成以及通过激活 AMP 激活的蛋白激酶（AMPK）和过氧化物酶体增殖物激活受体（PPAR）-α 来促进脂肪酸 β 氧化，从而减轻油酸暴露的 HepG2 细胞（0.5mM）中的细胞内脂质积累。BBM（5μM）通过 LKB1（Ser-428）诱导 AMPK 激活（P<0.001），并提高 AMP:ATP 比值（P<0.001）。AMPK 激活负调控 mTOR，并限制 SREBP-1c 的核易位，抑制脂肪生成蛋白硬脂酰辅酶 A 去饱和酶-1（SCD-1）和脂肪酸合酶（FAS）（P<0.001）。BBM 刺激氧化还原敏感核因子红细胞 2 相关因子 2（Nrf2）的核易位，并增加肝脏中 Nrf2 反应性酶血红素加氧酶 1（HO-1）和醌氧化还原酶 1（Nqo-1）的表达。BBM 处理通过显著增强肝脏抗氧化防御[超氧化物歧化酶（SOD，P<0.001）、过氧化氢酶（P<0.001）和细胞内谷胱甘肽（P<0.01）]和减少 NF-κB 调节的促炎细胞因子（TNF-α和 IL-6）水平，来减少氧化爆发和促炎反应。TEM 分析证实，线粒体结构破坏和线粒体大小减小（50.97%，P<0.001）在脂肪变性 HepG2 细胞中发生，这一现象通过 5μM BBM 处理（与对照组相比，71.84%，P<0.01）得到显著预防。预先用化合物 C（AMPK 抑制剂，25μM）处理可大大抑制 BBM 表现出的抗脂肪变性特性，证实了 AMPK 信号通路的参与。综上所述，结果表明，BBM 通过 AMPK/mTOR/SREBP-1c 轴介导的脂质代谢调节减少细胞内脂质积累，并通过促进 AMPK/Nrf2 结合来提高 Nrf2 的核稳定性，从而改善氧化应激/促炎反应。
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