Digestive and Lifestyle Diseases, Department of Human and Environmental Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
Department of International Island and Community Medicine, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan.
PLoS One. 2017 Apr 12;12(4):e0174913. doi: 10.1371/journal.pone.0174913. eCollection 2017.
Neutrophil infiltration of the liver is a typical feature of alcoholic liver injury. Human neutrophil peptide (HNP)-1 is an antimicrobial peptide secreted by neutrophils. The aim of this study was to determine if HNP-1 affects ethanol-induced liver injury and to examine the mechanism of liver injury induced by HNP-1.
Transgenic (TG) mice expressing HNP-1 under the control of a β-actin-based promoter were established. Ethanol was orally administered to HNP-1 TG or wild-type C57BL/6N (WT) mice. SK-Hep1 hepatocellular carcinoma cells were used to investigate the effect of HNP-1 on hepatocytes in vitro.
After 24 weeks of ethanol intake, hepatic fibrosis and hepatocyte apoptosis were significantly more severe in TG mice than in WT mice. Levels of CD14, TLR4, and IL-6 in liver tissues were higher in TG mice than in WT mice. Apoptosis was accompanied by higher protein levels of caspase-3, caspase-8, and cleaved PARP in liver tissue. In addition, phosphorylated ASK1, ASK1, phosphorylated JNK, JNK1, JNK2, Bax, Bak and Bim were all more abundant in TG mice than in WT mice. In contrast, the level of anti-apoptotic Bcl2 in the liver was significantly lower in TG mice than in WT mice. Analysis of microRNAs in liver tissue showed that miR-34a-5p expression was significantly higher in TG mice than in WT mice. Furthermore, in the presence of ethanol, HNP-1 increased the apoptosis with the decreased level of Bcl2 in a concentration-dependent manner in vitro.
HNP-1 secreted by neutrophils may exacerbate alcohol-induced hepatic fibrosis and hepatocyte apoptosis with a decrease in Bcl2 expression and an increase in miR-34a-5p expression.
中性粒细胞浸润肝脏是酒精性肝损伤的一个典型特征。人中性粒细胞肽（HNP）-1 是中性粒细胞分泌的一种抗菌肽。本研究旨在确定 HNP-1 是否影响乙醇诱导的肝损伤，并探讨 HNP-1 诱导肝损伤的机制。
构建了在β-肌动蛋白启动子控制下表达 HNP-1 的转基因（TG）小鼠。用乙醇对 HNP-1 TG 或野生型 C57BL/6N（WT）小鼠进行口服给药。使用 SK-Hep1 肝癌细胞在体外研究 HNP-1 对肝细胞的影响。
在摄入乙醇 24 周后，TG 小鼠的肝纤维化和肝细胞凋亡比 WT 小鼠更为严重。TG 小鼠肝组织中 CD14、TLR4 和 IL-6 水平高于 WT 小鼠。凋亡伴随着肝组织中 caspase-3、caspase-8 和裂解 PARP 的蛋白水平升高。此外，TG 小鼠中磷酸化 ASK1、ASK1、磷酸化 JNK、JNK1、JNK2、Bax、Bak 和 Bim 均比 WT 小鼠更为丰富。相反，TG 小鼠肝组织中抗凋亡 Bcl2 的水平明显低于 WT 小鼠。肝组织 microRNA 分析显示，TG 小鼠 miR-34a-5p 的表达明显高于 WT 小鼠。此外，在乙醇存在的情况下，HNP-1 以浓度依赖的方式增加了体外的细胞凋亡，同时降低了 Bcl2 的水平。
中性粒细胞分泌的 HNP-1 可能通过降低 Bcl2 表达和增加 miR-34a-5p 表达，加重酒精引起的肝纤维化和肝细胞凋亡。
