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卫生威胁，其特征在于从脂肪变性， 肝细胞损伤、炎症、纤维化和肝细胞癌（HCC）。一个关键的未解之谜是 炎症和肝纤维化如何产生“促致癌基质”，促进 肝细胞癌（HCC），即使没有共存的肝硬化。这些基质变化的核心是 肝星状细胞（HSC）的活化，HSC是居住在窦周的富含维生素A的细胞， 在一些实施方案中，肿瘤细胞转分化成肌成纤维细胞（癌症相关成纤维细胞，或CAF）以分泌宿主细胞外基质。 基质成分、生长因子和细胞因子。本研究的目的是阐明肝细胞的作用， 星形细胞在NASH和HCC发病机制中的作用。我们和我们的合作者已经开发了两个高度 HSC耗竭的有效，互补模型，可以解决理解其作用的关键差距， NASH纤维化和HCC：1）JEDI（“Just EGFP death inducing”）T细胞，其中CD 8 + T细胞被工程化以杀死 将表达绿色荧光蛋白（GFP）的细胞给予转基因小鼠，其中GFP被驱动 通过b-PDGF受体启动子，杀死99%的HSC; 2）靶向尿激酶纤溶酶原的CAR T细胞 活化受体（uPAR），其仅消除鼠肝脏中的衰老HSC。与此同时，我们创造了 高度可重复的鼠NASH模型，忠实地复制了组织学、纤维化进展和HCC 人类NASH我们的中心假设是NASH中活化和衰老的HSC表达独特的驱动因子 这有助于肿瘤倾向的基质微环境。因此，本提案同时调查了 HSC对NASH的动力学和独特贡献，以及它们产生的引起NASH的基质异常， 到HCC。我们将在三个相互关联但又不同的具体目标中解决这一假设：1）定义 正常和NASH中HSC耗竭前后的动力学、起源和细胞特征 2）确定衰老和非衰老HSC对NASH纤维化的相对贡献， 3）在鼠和人NASH中鉴定HCC的HSC衍生的基质驱动因子。这种创新方法 利用独特的动物模型是重要的，因为它将产生对HSC生物学的基本新见解 在健康和疾病中，定义它们调节特异性基质驱动因子，并将小鼠的异常 以建立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.