基于PGC-1ɑ/Irisin/UCP1通路探讨枸杞多糖对非酒精脂肪肝肝细胞线粒体功能障碍的调控机制

Mitochondrial dysfunction and oxidative stress were thought to be the key mechanism of accelerated fatty degeneration and started the process of nonalcoholic fatty liver disease(NAFLD) and liver fibrosis.Irisin has been proposed to act as a hormone on subcutaneous white fat cells increasing energy expenditure by means of a program of brown-fat-like development and improving sugar lipid transport, mitochondrial function. But the effect of combination of the both the mechanism of action on nonalcoholic fatty liver disease (NAFLD) has not yet been elucidated. Dietary regulation of mitochondria function will be fatty liver disease prevention and control of potential targets. Our previous study showed that wolfberry reduced oxidative stress, decreased the inflammatory factors and blood lipid levels, but the effects and underlying mechanisms of lycium barbarum polysaccharide（LBP） on regulatory mitochondrial dysfunction in the process of nonalcoholic fatty liver disease has not been clarified. In the present study, we attempt to establish an animal model of NAFLD by high-fat diet and investigate the effects of LBP on the mitochondrial biogenesis, mitochondrial autophagy and mitochondrial function in different tissues of rats with NAFLD. Our aim are ① to establish Nonalcoholic fatty liver cells model by L-02 cells were treated by 20µg/ml oleic acid (oleic acid was solutioned by 0. 5% DMSO) for 72h to induce the Nonalcoholic fatty liver cell model. ② To observe the effect of different concentrations LBP on protein expression levels of PGC-1α/Irisin/UCP1, lipid accumulation and mitochondrial damage in NAFLD cells model. ③ To reveal the mechanisms by which LBP promotes mitochondrial biogenesis and mitochondrial autophagy via PGC-1ɑ/Irisin/UCP1 signaling pathway by using multiple morphological and molecular biological techniques in NAFLD cells model. The results of our study would provide the new insight into the prevention and treatment of NAFLD and represent attractive targets in the dietary modification for metabolic diseases.

线粒体功能障碍和氧化应激是加速脂肪变性和启动脂肪肝和纤维化进程的关键机制，Irisin作为肌细胞因子在提高糖脂的转运、线粒体功能及对肝细胞脂质代谢方面则扮演重要角色，但二者联合对非酒精性脂肪肝（NAFLD）作用机制尚未阐明。膳食调控肝细胞线粒体功能和脂质代谢为营养研究热点。课题组前期研究发现，枸杞子可降低氧化应激、炎性因子及血脂水平，但枸杞多糖对NAFLD中Irisin水平及线粒体功能调控机制尚未阐明。本项目在前期研究基础上，拟建立高脂喂养的NAFLD动物模型，观察枸杞多糖对肝线粒体生成、自噬功能影响；辅以油酸诱导正常人肝脏细胞 L-02细胞建立NAFLD细胞模型，观察枸杞多糖对肝细胞PGC-1α/Irisin/UCP1通路相关22个蛋白质表达影响和对肝细胞脂肪堆积、线粒体功能障碍作用，揭示枸杞多糖调控肝细胞Irisin和线粒体生成、自噬的分子机制。本研究结果将为NAFLD的防治提供新思路

线粒体功能障碍和氧化应激是加速脂肪变性和启动脂肪肝和纤维化进程的关键机制，Irisin作为肌细胞因子在提高糖脂的转运、线粒体功能及对肝细胞脂质代谢方面则扮演重要角色，枸杞子可降低氧化应激、炎性因子及血脂水平，本项目在前期研究基础上，拟建立高脂喂养的NAFLD动物模型，观察枸杞多糖对肝线粒体功能影响；辅以油酸诱导正常人肝脏细胞 L-02细胞建立NAFLD细胞模型，观察枸杞多糖对肝细胞PGC-1α/Irisin/UCP1通路相关蛋白表达影响和对肝细胞脂肪堆积、线粒体功能障碍作用，揭示枸杞多糖调控肝细胞Irisin和线粒体生成的分子机制。①枸杞多糖可以改善NAFLD细胞氧化应激水平，通过上调PGC-1α、NRF-1、TFAM，下调UCP2表达对非酒精脂肪肝肝细胞模型的保护作用；②在肝脏脂质沉积阶段不同剂量枸杞多糖和有氧运动可以通过调控PGC-1α、FNDC5、Irisin表达对非酒精脂肪肝大鼠的保护作用；能够显著增加肝脏UCP2并下调SIRT3的表达，使线粒体功能障碍得到改善；并且枸杞多糖联合运动通过PGC-1 α/FNDC5/Irisin 途径而改善高脂饮食诱导大鼠的胰岛素抵抗；④在肌肉脂质沉积阶段：枸杞多糖和有氧运动干预对非酒精脂肪肝大鼠β细胞功能受损发挥保护作用：枸杞多糖联合有氧运动通过改善脂肪酸氧化对非酒精性脂肪肝炎脂质沉积发挥改善作用；通过UCP2/SIRT3途径对非酒精性脂肪肝炎氧化应激发挥改善作用；通过TLR4/NF-kB途径对非酒精性脂肪肝炎症反应发挥改善作用；通过PI3K/AKT信号通路对非酒精性脂肪肝大鼠的胰岛素抵抗发挥改善作用。本项目全面系统的研究枸杞多糖在脂代谢异常发生发展过程中肝脏脂质沉积（胰岛素抵抗）和肌肉脂质沉积（β细胞功能受损）阶段脂代谢异常发生发展过程中对线粒体功能的影响，将为2型糖尿病的防治提供新的膳食策略和防治靶点；为宁夏枸杞防治2型糖尿病提供新的科学依据。