Department of Medicine, Division of Gastroenterology and Hepatology, Shinshu University School of Medicine, Matsumoto, Japan.
Consultation Center for Liver Diseases, Shinshu University Hospital, Matsumoto, Japan.
Liver Int. 2024 Feb;44(2):483-496. doi: 10.1111/liv.15792. Epub 2023 Nov 27.
Hepatic overexpression of the thrombospondin 2 gene (THBS2) and elevated levels of circulating thrombospondin 2 (TSP2) have been observed in patients with chronic liver disease. This study aimed to identify the specific cells expressing THBS2/TSP2 in non-alcoholic fatty liver disease (NAFLD) and investigate the underlying mechanism behind THBS2/TSP2 upregulation.
Comprehensive NAFLD liver gene datasets, including single-cell RNA sequencing (scRNA-seq), in-house NAFLD liver tissue, and LX-2 cells derived from human hepatic stellate cells (HSCs), were analysed using a combination of computational biology, genetic, immunological, and pharmacological approaches.
Analysis of the genetic dataset revealed the presence of 1433 variable genes in patients with advanced fibrosis NAFLD, with THBS2 ranked among the top 2 genes. Quantitative polymerase chain reaction (qPCR) examination of NAFLD livers showed a significant correlation between THBS2 expression and fibrosis stage (r = .349, p < .001). In support of this, scRNA-seq data and in situ hybridization demonstrated that the THBS2 gene was highly expressed in HSCs of NAFLD patients with advanced fibrosis. Pathway analysis of the gene dataset revealed THBS2 expression to be associated with the transforming growth factor beta (TGFβ) pathway and collagen gene activation. Moreover, the activation of LX-2 cells with TGFβ increased THBS2/TSP2 and collagen expression independently of the TGFβ-SMAD2/3 pathway. THBS2 gene knockdown significantly decreased collagen expression in LX-2 cells.
THBS2/TSP2 is highly expressed in HSCs and plays a role in regulating fibrogenesis in NAFLD patients. THBS2/TSP2 may therefore represent a potential target for anti-fibrotic therapy in NAFLD.
在慢性肝病患者中观察到血小板反应蛋白 2 基因（THBS2）在肝脏中的过表达和循环血小板反应蛋白 2（TSP2）水平升高。本研究旨在鉴定非酒精性脂肪性肝病（NAFLD）中表达 THBS2/TSP2 的特定细胞，并探讨 THBS2/TSP2 上调的潜在机制。
使用计算生物学、遗传、免疫和药理学方法相结合，对包括单细胞 RNA 测序（scRNA-seq）在内的综合 NAFLD 肝脏基因数据集、内部 NAFLD 肝脏组织和源自人肝星状细胞（HSCs）的 LX-2 细胞进行分析。
对遗传数据集的分析显示，纤维化进展的 NAFLD 患者中存在 1433 个可变基因，THBS2 排在前 2 位基因之列。NAFLD 肝脏的定量聚合酶链反应（qPCR）检查显示 THBS2 表达与纤维化阶段之间存在显著相关性（r=0.349，p<0.001）。支持这一点的是，scRNA-seq 数据和原位杂交表明 THBS2 基因在纤维化进展的 NAFLD 患者的 HSCs 中高度表达。基因数据集的通路分析显示，THBS2 表达与转化生长因子β（TGFβ）途径和胶原基因激活相关。此外，用 TGFβ 激活 LX-2 细胞可独立于 TGFβ-SMAD2/3 途径增加 THBS2/TSP2 和胶原表达。THBS2 基因敲低可显著降低 LX-2 细胞中的胶原表达。
THBS2/TSP2 在 HSCs 中高表达，在调节 NAFLD 患者的纤维化中发挥作用。因此，THBS2/TSP2 可能成为 NAFLD 抗纤维化治疗的潜在靶点。
