Role of gp91phox in Hepatic MF Programming and Alcohol Liver Disease

 描述(申请人提供)：酒精性肝病(ALD)在美国影响着1000多万人，占与肝硬变相关的死亡的近一半。更好地了解这种疾病的发病机制对于开发新的治疗方法是必要的，目前这种治疗方法相当有限。先天性免疫系统在ALD的发病机制中起着重要作用。巨噬细胞(MΦ)是一种主要的天然免疫细胞，在许多慢性炎症性疾病中扮演着重要角色和治疗靶点。有证据表明，肝MΦS在酒精性肝病的发生发展中起重要作用。在患者和动物模型中，在ALD的所有阶段，肝脏MΦ的数量都增加，表明MΦ激活的因子也增加。肝脏MΦS是一个表型和功能不同的异质性群体。除了库普弗细胞(KCs)外，我们最近还发现，慢性酒精喂养会导致肝脏中浸润性MΦS(IM)的募集，该细胞包括一个促炎的Ly6chi亚群和一个抗炎的、具有组织保护作用的Ly6Clow亚群。死亡细胞的吞噬作用(泡泡吞噬)促进了Ly6chi IMS向Ly6Clow IMS的转换。此外，我们还发现gp91Phox-/-小鼠的肝脏M-ΦS具有明显的吞噬功能。有趣的是，与乙醇喂养的WT小鼠相比，gp91Phox-/-小鼠的Ly6chi/Ly6Clow IMS比例以及肝脏损伤程度都显著高于乙醇喂养的WT小鼠。这些结果导致了我们的假设，即gp91Phox通过调节MΦ的吞噬作用，在组织修复肝MΦS的程序设计中发挥关键作用，从而保护肝脏免受碱性磷酸酶损伤。我们提出了两个特定的目标来检验这一假说：(目标1)，研究gp91Phox在乙醇诱导的肝脏炎症和损伤中的保护作用。在两种ALD模型中，将比较WT和gp91Phox-/-小鼠的肝脏损伤和炎症程度。此外，还将进行骨髓嵌合体实验，以阐明肝脏MΦS在gp91Phox-/-小鼠对酒精性肝病易感性增加中的作用。(目的2)研究gp91Phox缺失对肝脏MΦS泡腾诱导程序化的影响。从乙醇喂养的WT和gp91Phox-/-小鼠的肝脏中分离到MΦS的不同亚群。两个品系的小鼠之间将比较每个种群的基因图谱。此外，还将比较来自WT和gp91Phox-/-小鼠的每个肝脏MΦ群体的吞噬能力和吞噬对细胞表型的影响。

 DESCRIPTION (provided by applicant): Alcoholic liver disease (ALD) affects more than 10 million people in the U.S. and accounts for nearly half of liver cirrhosis-associated deaths. A better understanding of the pathogenesis of the disease is necessary to develop new therapies, which are currently quite limited. The innate immune system plays an important role in the pathogenesis of ALD. Macrophages (MΦ) is a major type of cells of the innate immunity, and has emerged as a critical player and therapeutic target in many chronic inflammatory diseases. Evidence suggests that hepatic MΦ s are important in the development and progression of ALD. In patients and animal models, increased numbers of hepatic MΦ are found in all stages of ALD, and factors indicating MΦ activation are elevated. Hepatic MΦ s are a heterogeneous population with diverse phenotype and functions. Aside from resident Kupffer cells (KCs), we recently discovered that chronic ethanol feeding to mice causes the hepatic recruitment of infiltrating MΦ s (IMs), which consist of a pro-inflammatory Ly6Chi subset and an anti- inflammatory, tissue-protective Ly6Clow subset. Phagocytosis of dead cells (efferocytosis) promotes the switching of Ly6Chi IMs to Ly6Clow IMs. Moreover, we found that hepatic MΦ s from gp91phox-/- mice have impaired efferocytosis ability. Interestingly, compared with ethanol-fed WT mice, the ratio of Ly6Chi/Ly6Clow IMs, as well as the degree of liver injury, are significantly higher in gp91phox-/- mice. These results led to our hypothesis that gp91phox, through regulating MΦ efferocytosis, plays a critical role in the programming of tissue- restorative hepatic MΦ s, thereby protecting the liver from ALD. We propose two Specific Aims to examine this hypothesis: (Aim 1), Investigate the protective role of gp91phox in ethanol-induced liver inflammation and injury. The degrees of liver injury and inflammation will be compared between WT and gp91phox-/- mice in two models of ALD. Furthermore, bone marrow chimera experiments will be performed to elucidate the contribution of hepatic MΦs to the increased susceptibility of gp91phox-/- mice to ALD. (Aim 2), Investigate the impact of gp91phox-deletion on efferocytosis-induced programming of hepatic MΦs. Various subpopulations of MΦs will be isolated from the livers of ethanol-fed WT and gp91phox-/- mice. The gene profiles of each population will be compared between the two strains of mice. Moreover, the efferocytosis ability and the impact of efferocytosis on the cell phenotype will be compared in each hepatic MΦ population from WT and gp91phox-/- mice.