Mohamed Islam N, Sarhan Nahla Reda, Eladl Mohamed Ahmed, El-Remessy Azza B, El-Sherbiny Mohamed
Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, California Northstate University, Elk Grove, CA, USA; Augusta Biomedical Research Corporation, Charlie Norwood VA Medical Center, Augusta, GA, USA.
Department of Histology & Cell Biology, Faculty of Medicine, Mansoura University, Egypt.
Acta Histochem. 2018 Apr;120(3):242-254. doi: 10.1016/j.acthis.2018.02.006. Epub 2018 Feb 23.
Endemic prevalence of obesity is associated with alarming increases in non-alcoholic steatohepatitis (NASH) with limited available therapeutics. Toll-like receptor2 (TLR2) and Nod-like receptor protein 3 (NLRP3) Inflammasome are implicated in hepatic steatosis, inflammation and fibrosis; the histological landmark stages of NASH. TXNIP, a member of α-arrestin family activates NLRP3 in response to various danger stimuli. The aim of current work was to investigate the effect of TXNIP genetic deletion on histological manifestations of high fat diet-induced steatohepatitis and activation of TLR2-NLRP3-inflammasome axis. Wild-type mice (WT) and TXNIP knock out (TKO) littermates were randomized to normal diet (WT-ND and TKO-ND) or high fat diet (HFD, 60% fat) (WT-HFD and TKO-HFD). After 8-weeks, liver samples from all groups were evaluated by histological, immunohistochemical and western blot analysis. HFD resulted in significant induction of micro and macrovesicular hepatic steatosis, that was associated with increased inflammatory immune cell infiltration in WT-HFD compared with WT-ND and TKO-ND controls, but not in TKO-HFD group. In parallel, WT-HFD group showed significant fibrosis and α-SMA expression; a marker of pro-fibrotic stellate-cell activation, in areas surrounding the central vein and portal circulation, versus all other groups. Western blot revealed increased activation of TLR2-NLRP3 inflammasome pathway and downstream IL-1β and TNFα in WT-HFD group, but not in TKO-HFD group. IL-1β expression coincided within the same areas of steatosis, inflammatory cell infiltration, collagen deposition and α-SMA expression in WT-HFD mice, that was significantly reduced in TKO-HFD mice. In conclusion, TXNIP deletion ameliorates the HFD-induced steatosis, inflammatory and fibrotic response via modulation of TLR2-NLRP3 inflammasome axis. Targeting TXNIP-TLR2-NLRP3 pathway may provide potential therapeutic modalities for NASH treatment.
肥胖的地方流行率与非酒精性脂肪性肝炎（NASH）令人担忧的增加有关，而可用的治疗方法有限。Toll样受体2（TLR2）和Nod样受体蛋白3（NLRP3）炎性小体与肝脂肪变性、炎症和纤维化有关；这些是NASH的组织学标志性阶段。TXNIP是α- Arrestin家族的成员，可响应各种危险刺激激活NLRP3。当前工作的目的是研究TXNIP基因缺失对高脂肪饮食诱导的脂肪性肝炎组织学表现以及TLR2-NLRP3炎性小体轴激活的影响。野生型小鼠（WT）和TXNIP基因敲除（TKO）同窝小鼠被随机分为正常饮食（WT-ND和TKO-ND）或高脂肪饮食（HFD，60%脂肪）（WT-HFD和TKO-HFD）。8周后，通过组织学、免疫组织化学和蛋白质印迹分析评估所有组的肝脏样本。与WT-ND和TKO-ND对照组相比，HFD导致WT-HFD组出现明显的微泡性和大泡性肝脂肪变性，并伴有炎症免疫细胞浸润增加，但TKO-HFD组未出现。同时，与所有其他组相比，WT-HFD组在中央静脉和门静脉循环周围区域显示出明显的纤维化和α-SMA表达；α-SMA是促纤维化星状细胞激活的标志物。蛋白质印迹显示WT-HFD组中TLR2-NLRP3炎性小体途径以及下游IL-1β和TNFα的激活增加，但TKO-HFD组未出现。在WT-HFD小鼠中，IL-1β表达与脂肪变性、炎性细胞浸润、胶原沉积和α-SMA表达的相同区域一致，而在TKO-HFD小鼠中显著降低。总之，TXNIP缺失通过调节TLR2-NLRP3炎性小体轴改善了HFD诱导的脂肪变性、炎症和纤维化反应。靶向TXNIP-TLR2-NLRP3途径可能为NASH治疗提供潜在的治疗方式。
