Department of Endocrinology and Metabolism, Zhongshan Hospital, and Fudan Institute for Metabolic Diseases, Fudan University, Shanghai, China.
Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai, China.
J Hepatol. 2020 Jan;72(1):156-166. doi: 10.1016/j.jhep.2019.09.014. Epub 2019 Sep 27.
BACKGROUND & AIMS: Clinical evidence has indicated a close link between non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD). However, the underlying mechanism remains to be elucidated. This study aimed to explore a potential role of hepatocyte-derived extracellular vesicles (EVs) in endothelial inflammation and atherogenesis in the context of NAFLD.
EVs were isolated, quantified and characterized from steatotic hepatocytes. An endothelial cell-specific PCR array was used to screen the functional properties of EVs. Profiling of global microRNA expression was conducted in EVs. The expression level and biological function of microRNA-1 (miR-1) was determined by quantitative PCR, immunoblot and reporter gene assays, respectively. The in vivo effect of miR-1 on atherogenesis was investigated in apolipoprotein E (ApoE)-deficient mice administered with a miR-1-specific inhibitor, antagomiR-1.
Steatotic hepatocytes released more EVs, which had significantly altered miRNA expression profiles compared to the EVs released by control hepatocytes. Endothelial cells co-cultured with steatotic hepatocytes, or treated with their EVs or miR-1, expressed significantly more proinflammatory molecules, as well as exhibiting increased NF-κB activity and reduced Kruppel-like factor 4 (KLF4) expression. EV-induced endothelial inflammation was prevented by either downregulation or inhibition of miR-1. While miR-1 treatment suppressed KLF4 expression and reporter gene activity, overexpression of KLF4 dramatically abolished the miR-1-induced endothelial inflammation. Moreover, not only did the miR-1 inhibitor reduce endothelial inflammation in vitro, but it also attenuated atherogenesis in ApoE-deficient mice.
Steatotic hepatocyte-derived EVs promote endothelial inflammation and facilitate atherogenesis by miR-1 delivery, KLF4 suppression and NF-κB activation. The findings illustrate an important role of hepatocyte-derived EVs in distant communications between the liver and vasculature, suggesting a new mechanism underlying the link between NAFLD and CVD.
Non-alcoholic fatty liver disease (NAFLD), a condition highly prevalent in obese and/or diabetic patients, is emerging as an independent risk factor of cardiovascular disease. Herein, we demonstrated that extracellular vesicles, released by hepatocytes under NAFLD conditions, cause vascular endothelial inflammation and promote atherosclerosis. Within these toxic vesicles, we identified a small molecular cargo that acted as a potent inducer of endothelial inflammation. By inhibiting this cargo's function, a specific gene-based inhibitor profoundly attenuated atherogenesis in mice, uncovering a novel mechanism which may be used to prevent or treat cardiovascular disease in patients with NAFLD.
临床证据表明，非酒精性脂肪性肝病（NAFLD）与心血管疾病（CVD）之间存在密切联系。然而，其潜在机制尚待阐明。本研究旨在探讨肝细胞来源的细胞外囊泡（EVs）在 NAFLD 背景下内皮炎症和动脉粥样硬化形成中的潜在作用。
从脂肪变性的肝细胞中分离、定量和鉴定 EVs。使用内皮细胞特异性 PCR 阵列筛选 EVs 的功能特性。对 EVs 中的全局 microRNA 表达进行分析。通过定量 PCR、免疫印迹和报告基因分析分别确定 microRNA-1（miR-1）的表达水平和生物学功能。用 miR-1 特异性抑制剂 antagomiR-1 处理载脂蛋白 E（ApoE）缺陷小鼠，研究 miR-1 在体内对动脉粥样硬化形成的影响。
脂肪变性的肝细胞释放更多的 EVs，与对照肝细胞释放的 EVs 相比，这些 EVs 的 microRNA 表达谱发生了显著改变。与脂肪变性的肝细胞共培养或用其 EVs 或 miR-1 处理的内皮细胞，表达了更多的促炎分子，并且 NF-κB 活性增加，Kruppel 样因子 4（KLF4）表达减少。下调或抑制 miR-1 可防止 EV 诱导的内皮炎症。miR-1 处理抑制 KLF4 表达和报告基因活性，而过表达 KLF4 则可完全消除 miR-1 诱导的内皮炎症。此外，miR-1 抑制剂不仅在体外减轻了内皮炎症，而且还减轻了 ApoE 缺陷小鼠的动脉粥样硬化形成。
脂肪变性的肝细胞衍生的 EV 通过 miR-1 传递、KLF4 抑制和 NF-κB 激活促进内皮炎症和动脉粥样硬化形成。研究结果表明，肝细胞衍生的 EV 在肝脏和血管之间的远程通讯中起着重要作用，提示 NAFLD 和 CVD 之间存在新的关联机制。
非酒精性脂肪性肝病（NAFLD）是一种在肥胖和/或糖尿病患者中高度流行的疾病，它正成为心血管疾病的一个独立危险因素。在此，我们发现，在 NAFLD 条件下，肝细胞释放的细胞外囊泡（EVs）可引起血管内皮炎症，并促进动脉粥样硬化形成。在这些毒性 EVs 中，我们鉴定出一种小分子 cargo，它可作为内皮炎症的有效诱导物。通过抑制该 cargo 的功能，一种基于特定基因的抑制剂可显著减弱小鼠的动脉粥样硬化形成，揭示了一种新的机制，可能用于预防或治疗患有 NAFLD 的患者的心血管疾病。
Zotero 插件