Saikia Paramananda, Bellos Damien, McMullen Megan R, Pollard Katherine A, de la Motte Carol, Nagy Laura E
Department of Pathobiology, Center for Liver Disease Research, Cleveland Clinic, Cleveland, Ohio.
Department of Molecular Medicine, Case Western Reserve University, Cleveland, Ohio.
Hepatology. 2017 Aug;66(2):602-615. doi: 10.1002/hep.29144. Epub 2017 Jul 4.
Increased inflammatory signaling by Kupffer cells contributes to alcoholic liver disease (ALD). Here we investigated the impact of small, specific-sized hyaluronic acid of 35 kD (HA35) on ethanol-induced sensitization of Kupffer cells, as well as ethanol-induced liver injury in mice. Unbiased analysis of microRNA (miRNA) expression in Kupffer cells identified miRNAs regulated by both ethanol and HA35. Toll-like receptor 4 (TLR4)-mediated signaling was assessed in primary cultures of Kupffer cells from ethanol- and pair-fed rats after treatment with HA35. Female C57BL6/J mice were fed ethanol or pair-fed control diets and treated or not with HA35. TLR4 signaling was increased in Kupffer cells by ethanol; this sensitization was normalized by ex vivo treatment with HA35. Next generation sequencing of Kupffer cell miRNA identified miRNA 181b-3p (miR181b-3p) as sensitive to both ethanol and HA35. Importin α5, a protein involved in p65 translocation to the nucleus, was identified as a target of miR181b-3p; importin α5 protein was increased in Kupffer cells from ethanol-fed rats, but decreased by HA35 treatment. Overexpression of miR181b-3p decreased importin α5 expression and normalized lipopolysaccharide-stimulated tumor necrosis factor α expression in Kupffer cells from ethanol-fed rats. In a mouse model of ALD, ethanol feeding decreased miR181b-3p in liver and increased expression of importin α5 in nonparenchymal cells. Treatment with HA35 normalized these changes and also protected mice from ethanol-induced liver and intestinal injury.
miR181b-3p is dynamically regulated in Kupffer cells and mouse liver in response to ethanol and treatment with HA35. miR181b-3p modulates expression of importin α5 and sensitivity of TLR4-mediated signaling. This study identifies a miR181b-3p-importin α5 axis in regulating inflammatory signaling pathways in hepatic macrophages. (Hepatology 2017;66:602-615).
库普弗细胞炎症信号增强会导致酒精性肝病（ALD）。在此，我们研究了35kD的小尺寸特异性透明质酸（HA35）对乙醇诱导的库普弗细胞致敏以及小鼠乙醇诱导的肝损伤的影响。对库普弗细胞中微小RNA（miRNA）表达进行无偏分析，确定了受乙醇和HA35共同调控的miRNA。在用HA35处理后，对来自乙醇喂养和配对喂养大鼠的库普弗细胞原代培养物中Toll样受体4（TLR4）介导的信号进行了评估。雌性C57BL6/J小鼠喂食乙醇或配对喂养对照饮食，并给予或不给予HA35处理。乙醇使库普弗细胞中的TLR4信号增强；通过HA35离体处理可使这种致敏恢复正常。对库普弗细胞miRNA进行下一代测序，确定miRNA 181b - 3p（miR181b - 3p）对乙醇和HA35均敏感。转运蛋白α5是一种参与p65转位至细胞核的蛋白质，被确定为miR181b - 3p的靶标；乙醇喂养大鼠的库普弗细胞中转运蛋白α5蛋白增加，但HA35处理可使其减少。miR181b - 3p过表达降低了转运蛋白α5的表达，并使乙醇喂养大鼠的库普弗细胞中脂多糖刺激的肿瘤坏死因子α表达恢复正常。在ALD小鼠模型中，乙醇喂养降低了肝脏中miR181b - 3p的水平，并增加了非实质细胞中转运蛋白α5的表达。HA35处理使这些变化恢复正常，还保护小鼠免受乙醇诱导的肝脏和肠道损伤。
miR181b - 3p在库普弗细胞和小鼠肝脏中会因乙醇和HA35处理而动态调节。miR181b - 3p调节转运蛋白α5的表达以及TLR4介导信号的敏感性。本研究确定了miR181b - 3p - 转运蛋白α5轴在调节肝巨噬细胞炎症信号通路中的作用。（《肝脏病学》2017年；66：602 - 615）
