Single cell-resolved study of advanced murine MASH reveals a homeostatic pericyte signaling module

Non-alcoholic steatohepatitis (NASH) is associated with hepatic steatosis, intralobular inflammation, and fibrosis. The degree of hepatic fibrosis, mainly caused by excessive production of extracellular matrix proteins, is the sole predictor of liver-related and overall mortality in NASH patients. The hepatic stellate cells (HSCs) are causally implicated in fibrogenesis during NASH development but as sinusoidal pericytes also vital for vascular homeostasis of the healthy liver. Using single-cell RNA-sequencing we have analyzed whole liver plasticity and interrogated the transition of HSCs from pericytes in the healthy liver to collagen-producing cells in a diet-induced murine model of advanced NASH. We show how postprandial cues are sensed and integrated by HSCs promoting their phenotypic stabilization and, through paracrine mediators, sinusoidal health. While dominant under healthy conditions the basis for this multimodal signaling through stellate cell-specific Gs protein-coupled receptors and the bile-acid receptor NR1H4/FXR deteriorates in activated HSCs of the NASH liver. Expression of key signaling components were validated in situ in human and murine liver tissue supporting the translatability of our findings and pharmacological relevance in treatment of chronic liver diseases as NASH. Here we performed gene expression profiling analysis of primary hepatic stellate cells (in vitro) using data obtained from RNA-seq of cells treated with Foskolin (Fsk) for 3 hours and then 21 hours DMSO or Dimethylsulfoxid (DMSO) for 24 hours

非酒精性脂肪性肝炎（Non-alcoholic steatohepatitis, NASH）与肝脂肪变性、小叶内炎症及纤维化密切相关。肝纤维化主要由细胞外基质蛋白过度生成所介导，其程度是非酒精性脂肪性肝炎患者肝脏相关死亡及全因死亡的唯一预测因子。肝星状细胞（hepatic stellate cells, HSCs）不仅在非酒精性脂肪性肝炎发生发展过程中的纤维化发生环节中发挥因果性作用，同时作为血窦周细胞，对健康肝脏的血管稳态维持也至关重要。本研究借助单细胞RNA测序技术，分析了全肝脏可塑性，并探究了在饮食诱导的晚期非酒精性脂肪性肝炎小鼠模型中，肝星状细胞从健康肝脏中的周细胞向产胶原蛋白细胞转变的过程。本研究阐明了餐后信号如何被肝星状细胞感知并整合，进而促进其表型稳定，并通过旁分泌介质维持血窦健康状态。尽管在健康状态下，通过星状细胞特异性Gs蛋白偶联受体及胆汁酸受体NR1H4/FXR实现的多模态信号通路基础占据主导，但在非酒精性脂肪性肝炎肝脏的活化肝星状细胞中，该通路基础出现受损。我们通过对人源及小鼠肝脏组织的原位验证，确认了关键信号组分的表达水平，这证实了本研究结果的可转化性，以及其在非酒精性脂肪性肝炎等慢性肝病治疗中的药理学应用价值。本研究针对原代肝星状细胞开展了体外基因表达谱分析，所用数据来自经福司柯林（Foskolin, Fsk）处理3小时，随后以二甲基亚砜（Dimethylsulfoxid, DMSO）处理21小时（总干预时长为24小时）的细胞的RNA测序结果。