Hepatic stellate cells in NASH fibrosis and HCC

非酒精性脂肪性肝炎(NASH)是一种日益严重的公共健康威胁，其特征是脂肪变性的进展， 肝细胞损伤、炎症、纤维化和肝细胞癌。一个关键悬而未决的问题是 炎症和肝纤维化如何创造一种“致癌间质”，促进肿瘤的发展 肝细胞癌(HCC)，即使没有并存的肝硬变。这些间质改变的中心是 激活肝星状细胞(HSCs)，这是驻留在肝窦周围的富含维生素A的细胞， 转分化为肌成纤维细胞(癌症相关成纤维细胞，或CAF)以分泌大量细胞外 基质成分、生长因子和细胞因子。本研究的目的是阐明肝脏的作用。 星状细胞在NASH和肝细胞癌发病中的作用我们和我们的合作者开发了两个高度 高效、互补的HSC耗竭模型，可以弥补在理解HSC在 NASH纤维化与肝细胞癌：1)绝地(“只是EGFP死亡诱导”)T细胞，其中CD8+T细胞被设计为杀伤 将表达绿色荧光蛋白(GFP)的细胞接种到转基因小鼠中，在转基因小鼠中驱动GFP B-PDGF受体启动子对99%的HSCs的杀伤作用；2)靶向尿激酶型纤溶酶原的CAR T细胞 激活受体(UPAR)，只清除小鼠肝脏中衰老的HSCs。同时，我们已经创建了 一种高度可重复性的小鼠NASH模型，忠实地复制组织学、纤维化进展和肝细胞癌 人类纳什。我们的中心假设是NASH中激活的和衰老的HSCs表达独特的驱动因素 这有助于形成易患肿瘤的间质微环境。因此，本提案同时调查 造血干细胞在NASH中的动态和独特贡献，以及它们所产生的间质异常 去肝细胞癌。我们将在三个相互关联但截然不同的具体目标中阐述这一假设：1)定义 正常和NASH患者HSC耗竭前后的动态、起源和细胞特征 2)建立衰老和非衰老的HSC在NASH纤维化中的相对贡献和 3)在小鼠和人NASH中鉴定肝癌的HSC来源的基质驱动因素。这一创新方法 利用独特的动物模型具有重要意义，因为它将对HSC生物学产生根本性的新见解 在健康和疾病中，定义它们调节特定基质驱动因素，并将来自老鼠的异常联系起来 建立人类NASH-肝癌模型，以确定其作为潜在治疗靶点的临床相关性。

Non-alcoholic steatohepatitis (NASH) is a rising public health threat characterized by progression from steatosis, to hepatocyte injury, inflammation, fibrosis and hepatocellular carcinoma (HCC). A key unanswered question is how inflammation and hepatic fibrosis create a ‘pro-carcinogenic stroma’ that promotes the development of hepatocellular carcinoma (HCC), even without co-existent cirrhosis. Central to these stromal changes is the activation of hepatic stellate cells (HSCs), which are resident perisinusoidal, vitamin A-rich cells that transdifferentiate into myofibroblasts (cancer-associated fibroblasts, or CAFs) to secrete a host of extracellular matrix constituents, growth factors, and cytokines. The objective of this research is to clarify the role of hepatic stellate cells in the pathogenesis of NASH and HCC. We and our collaborators have developed two highly efficient, complementary models of HSC depletion that can address critical gaps in understanding their role in NASH fibrosis and HCC: 1) JEDI (“Just EGFP death inducing”) T-cells, in which CD8+ T cells engineered to kill cells that express green fluorescent protein (GFP) are administered to transgenic mice, in which GFP is driven by the b-PDGF receptor promoter, killing 99% of HSCs; 2) CAR T cells targeting urokinase plasminogen activated receptor (uPAR), which eliminate only senescent HSCs in murine liver. Concurrently, we have created a highly reproducible murine NASH model that faithfully replicates the histology, fibrosis progression and HCCs of human NASH. Our central hypothesis is that activated and senescent HSCs in NASH express unique drivers that contribute to a tumor-prone stromal microenvironment. Thus, this proposal concurrently investigates the dynamics and unique contributions of HSCs to NASH, and the stromal abnormalities they generate that give rise to HCC. We will address this hypothesis in three interrelated, but distinct Specific Aims:1) To define the dynamics, origin and cellular features of HSC repopulation before and after their depletion in normal and NASH mice; 2) To establish the relative contributions of senescent and non-senescent HSCs to NASH fibrosis and HCC; 3) To identify HSC-derived stromal drivers of HCC in murine and human NASH. This innovative approach leveraging unique animal models is significant because it will yield fundamental new insights into HSC biology in health and disease, define specific stromal drivers that they regulate, and link abnormalities from mouse models to human NASH-HCC to establish their clinical relevance as potential therapeutic targets.