Phillygenin ameliorates nonalcoholic fatty liver disease via TFEB-mediated lysosome biogenesis and lipophagy
Phillygenin ameliorates nonalcoholic fatty liver disease via TFEB-mediated lysosome biogenesis and lipophagy
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DOI：
10.1016/j.phymed.2022.154235
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发表时间：
2022-06-15
期刊：
影响因子：
7.9
通讯作者：
Peng, Liang
中科院分区：
文献类型：
--
作者：
Zhou, Wenling;Yan, Xu;Peng, Liang
背景：噬脂作用是一种自噬过程，将细胞内的脂滴运送到溶酶体中进行降解。近年来的研究发现，肝细胞溶酶体生物合成和自噬流的受损导致肝细胞吞噬脂肪功能失调，从而加剧了非酒精性脂肪性肝病（NAFLD）的发生。因此，在肝细胞中恢复自噬通量和脂肪吞噬的药物可能对这种日益流行的疾病具有治疗潜力。连翘苷元（Phillygenin，PHI）是从连翘中提取的一种木质素，具有保肝抗炎作用。然而，PHI对NAFLD的影响仍然未知。目的：探讨PHI对非酒精性脂肪肝（NAFLD）的保护作用及其机制。研究方法：在棕榈酸（PA）刺激的AML 12细胞和原代肝细胞，以及在高脂饮食（HFD）诱导的NAFLD小鼠中检查了PHI的作用。我们还使用转录因子EB（TFEB）敲低肝细胞和肝细胞特异性TFEB敲除（TFEB & U Δ; hep）小鼠进行机制研究。使用蛋白质印迹、免疫荧光技术和透射电子显微镜进行体内和体外研究。结果：PA刺激的肝细胞自噬流和溶酶体生物合成受到损害。PHI通过增加溶酶体生物合成和自噬流量减轻脂质沉积。它还刺激内质网Ca 2+释放，激活钙调神经磷酸酶，调节TFEB去磷酸化和核转位，并促进溶酶体生物合成。此外，PHI阻断了NLRP 3炎性体通路，并以自噬依赖的方式改善了肝细胞炎症。与体外结果一致，PHI改善了HFD小鼠的肝脏脂肪变性和炎症，但这些有益作用在肝细胞特异性TFEB敲除小鼠中被消除。结论：尽管已有研究报道PHI具有抗肝纤维化作用，但其是否具有抗NAFLD的保肝作用及其分子机制尚不清楚。在此，我们发现PHI通过调节肝细胞中的Ca2 +-钙调神经磷酸酶-TFEB轴来恢复脂肪吞噬并抑制脂质积聚和炎症。因此，PHI代表用于治疗NAFLD的治疗候选物。
Background: Lipophagy is an autophagic process, which delivers the intracellular lipid droplets to the lysosomes for degradation. Recent studies revealed that the impairment of lysosomal biogenesis and autophagic flux led to dysregulation of lipophagy in hepatocytes, which exacerbated the development of nonalcoholic fatty liver disease (NAFLD). Therefore, agents restoring autophagic flux and lipophagy in hepatocytes may have therapeutic potential against this increasingly prevalent disease. Phillygenin (PHI), a lignin extracted from Forsythia suspense, exerts hepatoprotective and anti-inflammatory effects. However, the effect of PHI on NAFLD remains unknown. Purpose: This study aimed to investigate the protective effect of PHI on NAFLD and elucidate the underlying mechanism. Methods: The effects of PHI were examined in palmitate (PA)-stimulated AML12 cells and primary hepatocytes, as well as in NAFLD mice induced by a high-fat diet (HFD). We also used transcription factor EB (TFEB) knockdown hepatocytes and hepatocyte-specific TFEB knockout (TFEB & UDelta;hep) mice for mechanistic studies. In vivo and in vitro studies were performed using western blots, immunofluorescence techniques, and transmission electron microscopy. Results: Our results indicated that autophagic flux and lysosome biogenesis in PA-stimulated hepatocytes were impaired. PHI alleviated lipid deposition by increasing lysosomal biogenesis and autophagic flux. It also stimulated the release of endoplasmic reticulum Ca2+ to activate calcineurin, which regulated TFEB dephosphorylation and nuclear translocation, and promoted lysosomal biogenesis. In addition, PHI blocked the NLRP3 inflammasome pathway and improved hepatocyte inflammation in an autophagy-dependent manner. Consistent with the in vitro results, PHI improved hepatic steatosis and inflammation in HFD mice, but these beneficial effects were eliminated in hepatocyte-specific TFEB knockout mice. Conclusion: Despite PHI has been reported to have anti-hepatic fibrosis effects, whether it has a hepatoprotective effects against NAFLD and the underlying molecular mechanism remain unclear. Herein, we found that PHI restored lipophagy and suppressed lipid accumulation and inflammation by regulating the Ca2+-calcineurin-TFEB axis in hepatocytes. Thus, PHI represents a therapeutic candidate for the treatment of NAFLD.