Cholesterol impairs hepatocyte lysosomal function causing M1 polarization of macrophages via exosomal miR-122-5p
Cholesterol impairs hepatocyte lysosomal function causing M1 polarization of macrophages via exosomal miR-122-5p
复制标题
DOI：
10.1016/j.yexcr.2019.111738
复制
发表时间：
2020-02-01
影响因子：
3.7
通讯作者：
Gong, Jianping
中科院分区：
文献类型：
--
作者：
Zhao, Zhibo;Zhong, Li;Gong, Jianping
非酒精性脂肪性肝炎（NASH）是全球健康的主要威胁。脂毒性和巨噬细胞介导的炎症在NASH的发病机制中起关键作用。在本研究中，我们发现血清低密度脂蛋白胆固醇（LDL - C）水平较高的个体患非酒精性脂肪性肝病（NAFLD）的患病率更高，且谷丙转氨酶、谷草转氨酶和碱性磷酸酶水平升高。逻辑回归分析显示，血清LDL - C水平是NAFLD患病率和预后的独立危险因素。在体外，我们使用氧化型低密度脂蛋白（ox - LDL）和巨噬细胞源性胆固醇（MACD - cholesterol）处理Huh7细胞，发现胆固醇负荷降低了溶酶体数量并损害了溶酶体酸化，减少了与溶酶体共定位的多囊泡体（MVBs）数量。巴弗洛霉素A1对溶酶体功能的抑制也抑制了溶酶体多囊泡体的降解，促进了Huh7细胞外泌体的释放。接下来，我们发现胆固醇负荷促进了Huh7细胞外泌体的释放。来自胆固醇负荷细胞的外泌体增加了M1标志物（诱导型一氧化氮合酶 - 1，iNOS - 1）阳性的THP - 1细胞比例，而不影响M2标志物（CD206）阳性细胞的比例。此外，在来自胆固醇负荷的Huh7细胞的外泌体中观察到miR - 122 - 5p水平升高。虽然miR - 122 - 5p模拟物促进了THP - 1细胞的M1极化，但下调Huh7细胞中的miR - 122 - 5p抑制了外泌体诱导的巨噬细胞活化和巨噬细胞相关炎症。这些发现表明胆固醇在NASH的发生和发展中起重要作用。胆固醇诱导的溶酶体功能障碍增加了肝细胞外泌体的释放，以miR - 122 - 5p依赖的方式导致M1极化和巨噬细胞诱导的炎症。
Nonalcoholic steatohepatitis (NASH) is a major threat to health worldwide. Lipotoxicity and macrophage-mediated inflammation play key roles in the pathogenesis of NASH. In this study, we found that individuals with higher serum LDL-C levels have a higher prevalence of nonalcoholic fatty liver disease (NAFLD) and elevated levels of glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase and alkaline phosphatase. A logistic regression analysis revealed that serum LDL-C level is an independent risk factor for the prevalence and prognosis of NAFLD. In vitro, we used ox-LDL and MACD-cholesterol to treat Huh7 cells and found that cholesterol loading reduced lysosomal quantity and impaired lysosomal acidification, reducing the number of multivesicular bodies (MVBs) colocalizing with lysosomes. The bafilomycin A1 inhibition of lysosomal function also inhibited lysosomal MVBs degradation, promoting the release of exosomes from the Huh7 cells. Next, we found that cholesterol loading promoted exosome release from the Huh7 cells. The exosomes from the cholesterol-loaded cells increased the ratio of the THP-1 cells positive for the M1 marker (iNOS-1) without affecting the ratio of the cells positive for the M2 marker (CD206). Moreover, an elevated level of miR-122-5p was observed in exosomes derived from the Huh7 cells loaded with cholesterol. While the miR-122-5p mimics promoted THP-1 M1 polarization, downregulating miR-122-5p in the Huh7 cells inhibited the exosome-induced activation of macrophages and macrophage-related inflammation. These findings suggest that cholesterol plays an important role in the development and progression of NASH. Cholesterol-induced lysosomal dysfunction increases exosome release from hepatocytes, resulting in Ml polarization and macrophage-induced inflammation in a miR-122-5pdependent manner.