脂肪甘油三酯脂肪酶（ATGL）是胰岛素抵抗和代谢功能障碍相关脂肪肝病（MASLD）的一个有吸引力的治疗靶点。本研究探讨了药物 ATGL 抑制对小鼠代谢功能障碍相关脂肪性肝炎 (MASH) 和纤维化发展的影响。注射链脲佐菌素的雄性小鼠喂食 HFD 以诱导 MASH。使用肝脏组织学、脂质组学、代谢组学、16s rRNA 和 RNA 测序将接受 ATGL 抑制剂 Atglistatin (ATGLi) 的小鼠与对照组进行比较。对用人 ATGL 抑制剂 NG-497 处理的人回肠类器官、HepG2 细胞和 Caco2 细胞、HepG2 ATGL 敲低细胞、凝胶迁移和荧光素酶测定进行分析，以获得机制见解。我们在低蛋氨酸胆碱缺乏的小鼠模型中验证了其对脂肪性肝炎和纤维化的益处。ATGLi 改善了血清肝酶、肝脂质含量和组织学肝损伤。从机制上讲，ATGLi 减弱 PPARα 信号传导，有利于亲水性胆汁酸 (BA) 合成，增加 Cyp7a1、Cyp27a1、Cyp2c70 的表达，并减少 Cyp8b1 的表达。此外，肠道 Cd36 和 Abca1 的减少以及 Abcg5 表达的增加，与含有亚油酸等 PUFA 的肝脏 TAG 物质水平的降低以及肝脏和血浆中胆固醇水平的降低一致。在用 NG-497 处理的回肠类器官中观察到与 PPARα 信号传导和肠道脂质转运相关的基因表达的类似变化。此外，HepG2 ATGL 敲除细胞显示 PPARα 靶基因表达减少，参与亲水性 BA 合成的基因上调，这与 ATGL 抑制剂存在下 PPARα 结合和荧光素酶活性降低一致。 ATGL 的抑制会减弱 PPARα 信号传导，转化为亲水性 BA ，干扰膳食脂质吸收，改善代谢紊乱。 NG-497 的验证为 MASLD 开辟了新的治疗视角。代谢功能障碍相关的脂肪肝病 (MASLD) 的全球患病率是一个重要的公共卫生问题。由于行为干预的依从性有限，因此药物策略是必要的，正如 FDA 最近批准瑞美罗所强调的那样。然而，由于我们目前对 MASLD 的机制理解和病理生理学导向的治疗选择仍然有限，因此迫切需要新的机制见解。我们目前的工作发现，在 MASH 和 MCD 小鼠模型中，使用 Atglistatin (ATGLi) 对脂质水解的关键酶 ATGL 进行药理学抑制，可以改善代谢功能障碍相关的脂肪性肝炎 (MASH)、纤维化以及代谢功能障碍的相关关键特征。诱发肝纤维化。从机制上讲，我们证明肝脏和肠道中 PPARα 信号传导的减弱有利于亲水性胆汁酸成分，最终干扰膳食脂质吸收。 ATGLi 的缺点之一是其缺乏针对人 ATGL 的功效，从而限制了其临床应用。在此背景下，我们可以证明，在人原代回肠来源的类器官、Caco2 细胞和 HepG2 细胞中使用人抑制剂 NG-497 抑制 ATGL 转化为类似于 ATGLi 的治疗机制。总的来说，这些发现通过抑制人类 ATGL 活性为 MASLD 治疗开发开辟了一条新途径。版权所有 © 2024 作者。由 Elsevier B.V. 出版。保留所有权利。

Adipose triglyceride lipase (ATGL) is an attractive therapeutic target in insulin resistance and metabolic dysfunction-associated steatotic liver disease (MASLD). This study investigated the effects of pharmacological ATGL inhibition on the development of metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis in mice.Streptozotocin-injected male mice were fed an HFD to induce MASH. Mice receiving the ATGL inhibitor, Atglistatin (ATGLi), were compared to controls using liver histology, lipidomics, metabolomics, 16s rRNA, and RNA sequencing. Human ileal organoids, HepG2 cells, and Caco2 cells treated with the human ATGL inhibitor NG-497, HepG2 ATGL knockdown cells, gel-shift, and luciferase assays were analysed for mechanistic insights. We validated its benefits on steatohepatitis and fibrosis in a low-methionine choline-deficient mouse model.ATGLi improved serum liver enzymes, hepatic lipid content, and histological liver injury. Mechanistically, ATGLi attenuated PPARα signalling, favouring hydrophilic bile acid (BA) synthesis with increased Cyp7a1, Cyp27a1, Cyp2c70, and reduced Cyp8b1 expression. Additionally, reduced intestinal Cd36 and Abca1, along with increased Abcg5 expression, were consistent with reduced levels of hepatic TAG-species containing PUFAs like linoleic acids as well as reduced cholesterol levels in the liver and plasma. Similar changes in gene expression associated with PPARα signaling and intestinal lipid transport were observed in ileal organoids treated with NG-497. Furthermore, HepG2 ATGL knockdown cells revealed reduced expression of PPARα target genes and upregulation of genes involved in hydrophilic BA synthesis, consistent with reduced PPARα binding and luciferase activity in the presence of the ATGL inhibitors.Inhibition of ATGL attenuates PPARα signalling, translating into hydrophilic BAs, interfering with dietary lipid absorption, and improving metabolic disturbances. The validation with NG-497 opens a new therapeutic perspective for MASLD.The global prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is a crucial public health concern. Since adherence to behavioural interventions is limited, pharmacological strategies are necessary, as highlighted by the recent FDA approval of resmetirom. However, since our current mechanistic understanding and pathophysiology-oriented therapeutic options for MASLD are still limited, novel mechanistic insights are urgently needed. Our present work uncovers that pharmacological inhibition of ATGL, the key enzyme in lipid hydrolysis using Atglistatin (ATGLi), improves metabolic dysfunction-associated steatohepatitis (MASH), fibrosis, and associated key features of metabolic dysfunction in a mouse model of MASH and MCD-induced liver fibrosis. Mechanistically, we demonstrated that attenuation of PPARα signalling in the liver and gut favours hydrophilic bile acid composition, ultimately interfering with dietary lipid absorption. One of the drawbacks of ATGLi is its lack of efficacy against human ATGL, thus limiting its clinical applicability. Against this backdrop, we could show that ATGL inhibition using the human inhibitor NG-497 in human primary ileum-derived organoids, Caco2 cells, and HepG2 cells translated into therapeutic mechanisms similar to ATGLi. Collectively, these findings open a new avenue for MASLD treatment development by inhibiting human ATGL activity.Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.