Kotulkar Manasi, Robarts Dakota R, Lin-Rahardja Kristi, McQuillan Tara, Surgnier Jordan, Tague Sarah E, Czerwinski Maciej, Dennis Katie L, Pritchard Michele T
Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas, USA.
Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, Kansas, USA.
Alcohol Clin Exp Res (Hoboken). 2023 Aug;47(8):1544-1559. doi: 10.1111/acer.15127. Epub 2023 Jun 18.
Chronic ethanol overconsumption promotes alcohol-associated liver disease (ALD), characterized by hepatocyte injury, inflammation, hepatic stellate cell (HSC) activation, and fibrosis. Hyaluronan (HA) concentration is greater in livers and blood from advanced ALD patients than patients with advanced non-ALD. In the liver, HSCs are the major HA producers. The relationship between ethanol, HA, and HSC activation is incompletely understood. Thus, here, we tested the hypothesis that ethanol enhances HSC activation in a HA-dependent manner.
Liver tissue microarrays (TMAs) containing steatotic livers from donors with or without a history of alcohol consumption were used to measure HA and collagen content. Mice were fed a moderate (2%, v/v) ethanol-containing diet or pair-fed control diet for 2 days, after which they were given a single carbon tetrachloride (CCl ) injection. To inhibit HA synthesis, we provided 4-methylumbelliferone (4MU) daily. We used LX2 cells, a human HSC cell line, to determine the impact ethanol had on LPS responses, with or without concurrent 4MU exposure.
CCl induced liver injury, but it did not differ between ethanol or control diet fed mice with or without 4MU treatment. Ethanol feeding enhanced CCl -induced hepatic HA content, which was paralleled by HA synthase (Has)2 transcript abundance; 4MU treatment normalized both. Consistently, HSC activation, assessed by measuring αSMA mRNA and protein, was induced by CCl exposure, enhanced by ethanol feeding, and normalized by 4MU. Hepatic transcripts, but not protein, for Ccl2 were enhanced by ethanol feeding and normalized by 4MU exposure. Finally, ethanol-exposed LX2 cells made more LPS-stimulated CCL2 mRNA and protein than cells not exposed to ethanol; 4MU prevented this.
These data show that ethanol augments HSC activation through HA synthesis and enhances hepatic profibrogenic features. Therefore, targeting HSC HA production could potentially attenuate liver disease in ALD patients.
长期过量摄入乙醇会引发酒精性肝病（ALD），其特征为肝细胞损伤、炎症、肝星状细胞（HSC）激活及纤维化。晚期ALD患者肝脏和血液中的透明质酸（HA）浓度高于晚期非ALD患者。在肝脏中，HSCs是主要的HA产生细胞。乙醇、HA与HSC激活之间的关系尚未完全明确。因此，在此我们检验了乙醇以HA依赖的方式增强HSC激活的假说。
使用包含有或无饮酒史供体的脂肪变性肝脏的肝组织微阵列（TMA）来测量HA和胶原蛋白含量。给小鼠喂食含适量（2%，v/v）乙醇的饮食或配对喂食对照饮食2天，之后单次注射四氯化碳（CCl）。为抑制HA合成，我们每日给予4-甲基伞形酮（4MU）。我们使用人HSC细胞系LX2细胞来确定乙醇对LPS反应的影响，同时或不同时给予4MU。
CCl诱导肝损伤，但在给予或未给予4MU治疗的情况下，喂食乙醇或对照饮食的小鼠之间无差异。喂食乙醇会增加CCl诱导的肝脏HA含量，同时HA合酶（Has）2转录本丰度也相应增加；4MU治疗可使两者恢复正常。同样，通过测量αSMA mRNA和蛋白评估的HSC激活由CCl暴露诱导，喂食乙醇会增强，而4MU可使其恢复正常。乙醇喂食会增加肝脏中Ccl2的转录本，但不增加蛋白，4MU暴露可使其恢复正常。最后，暴露于乙醇的LX2细胞比未暴露于乙醇的细胞产生更多LPS刺激的CCL2 mRNA和蛋白；4MU可阻止这种情况。
这些数据表明乙醇通过HA合成增强HSC激活并增强肝脏促纤维化特征。因此，针对HSC HA产生可能会减轻ALD患者的肝病。
