Xu L, Han J, Yang Z, Yang Y, Chen J, Wu X, Wang Q, Hong Y
Department of Histology and Embryology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, China.
Clinical Laboratory, Jinyang Hospital, Guizhou Medical University, Guiyang 550025, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2023 Jul 20;43(7):1164-1171. doi: 10.12122/j.issn.1673-4254.2023.07.13.
To explore the effect of leucine-rich α-2-glycoprotein (LRG1) derived from hepatocytes on activation of hepatic M1 Kupffer cells.
A metabolic dysfunction-associated fatty liver disease (MAFLD) model was established in BALB/c mice by high-fat diet (HFD) feeding for 16 weeks. Oleic acid was used to induce steatosis in primary cultures of mouse hepatocytes. The mRNA and protein expressions of LRG1 in mouse liver tissues and hepatocytes were detected by real-time PCR and Western blotting. Primary hepatic macrophages were stimulated with the conditioned medium (CM) from steatotic hepatocyte along with LRG1 or transforming growth factor-β1 (TGF-β1), or both for 24 h, and the expression levels of inducible nitric oxide synthase (iNOS) was detected with Western botting, and the mRNA expressions of iNOS, chemokine ligand 1 (CXCL-1) and interleukin-1β (IL-1β) were measured by RT-PCR. The MAFLD mice were injected with LRG1 (=6), TGF-β1 (=6), or both (=6) through the caudal vein, and the live tissues were collected for HE staining and immumohistochemical detection of F4/80 expression; the mRNA expressions of iNOS, CXCL-1 and IL-1β in liver tissues were detected using RT-PCR.
The mRNA and protein expression levels of LRG1 were significantly downregulated in the liver tissues of MAFLD mice and steatotic hepatocytes ( < 0.05). Treatment of the hepatic macrophages with CM from steatosis hepatocytes significantly enhanced the mRNA expression levels of iNOS, CXCL-1 and IL-1β, and these changes were significantly inhibited by the combined treatment with TGF-β1 and LRG1 ( < 0.05). In MAFLD mice, injections with either LRG1 or TGF-β1 alone reduced hepatic lipid deposition and intrahepatic macrophage infiltration, and these effects were significantly enhanced by their combined treatment, which also more strongly inhibited the mRNA expression levels of iNOS, CXCL-1 and IL-1β ( < 0.05).
LRG1 inhibits hepatic macrophage infiltration by enhancing TGF-β1 signaling to alleviate fatty liver inflammation in MAFLD mice.
探讨肝细胞来源的富含亮氨酸的α-2-糖蛋白（LRG1）对肝M1型库普弗细胞激活的影响。
通过高脂饮食（HFD）喂养16周，在BALB/c小鼠中建立代谢功能障碍相关脂肪性肝病（MAFLD）模型。用油酸诱导原代培养的小鼠肝细胞发生脂肪变性。采用实时PCR和蛋白质免疫印迹法检测LRG1在小鼠肝脏组织和肝细胞中的mRNA和蛋白表达。用来自脂肪变性肝细胞的条件培养基（CM）联合LRG1或转化生长因子-β1（TGF-β1）或两者刺激原代肝巨噬细胞24小时，用蛋白质免疫印迹法检测诱导型一氧化氮合酶（iNOS）的表达水平，用逆转录PCR法检测iNOS、趋化因子配体1（CXCL-1）和白细胞介素-1β（IL-1β）的mRNA表达。通过尾静脉给MAFLD小鼠注射LRG1（n = 6）、TGF-β1（n = 6）或两者（n = 6），收集肝脏组织进行苏木精-伊红（HE）染色和免疫组织化学检测F4/80表达；用逆转录PCR法检测肝脏组织中iNOS、CXCL-1和IL-1β的mRNA表达。
MAFLD小鼠肝脏组织和脂肪变性肝细胞中LRG1的mRNA和蛋白表达水平显著下调（P < 0.05）。用来自脂肪变性肝细胞的CM处理肝巨噬细胞显著提高了iNOS、CXCL-1和IL-1β的mRNA表达水平，而TGF-β1和LRG1联合处理可显著抑制这些变化（P < 0.05）。在MAFLD小鼠中，单独注射LRG1或TGF-β1均可减少肝脏脂质沉积和肝内巨噬细胞浸润，联合处理可显著增强这些作用，同时更强烈地抑制iNOS、CXCL-1和IL-1β的mRNA表达水平（P < 0.05）。
LRG1通过增强TGF-β1信号传导抑制肝巨噬细胞浸润，从而减轻MAFLD小鼠的脂肪肝炎症。
