Functional role of macrophage subsets in acetaminophen-induced acute liver failure and therapeutic implica-tions of its modulation by chemokine pathways

过量使用对乙酰氨基酚（paracetamol， APAP）导致的肝损伤是人类急性肝衰竭（ALF）的主要原因之一，这是一种危及生命的疾病，通常需要肝移植。虽然使用n -乙酰半胱氨酸可以从治疗上改善APAP毒性引起的初始肝细胞坏死，但APAP损伤后期的结果是由大量炎症反应决定的。在ALF的实验模型和患者中，可以在肝脏中发现不同的巨噬细胞亚群，这些巨噬细胞来自于驻留的Kupffer细胞和浸润的单核细胞。目前的假设是，巨噬细胞异质性在功能上影响apap相关和非apap相关的ALF的结果，干扰趋化因子介导的募集可以改善它们对肝损伤的贡献。在这个提议中，我们将研究巨噬细胞亚群的动态和分化，以及趋化因子受体CCR2（和其他途径）在apap诱导和其他急性肝损伤模型中的功能参与。在该小鼠模型中，将使用创新的药理学抑制剂来探索阻断CCR2（主要的CCR2配体）和CCR2本身的治疗潜力，从而实现临床应用的转化方法。具体目标是：1.；apap诱导的肝损伤中巨噬细胞亚群和CCR2依赖性炎症的表征和动力学（在三种急性肝损伤模型中使用转基因小鼠菌株，肝脏CCR2+单核细胞的活体多光子显微镜成像，通过基于纳米串的多重基因分析进行广泛表型分析，并通过过性转移进行功能验证）；2. 探索不同的趋化因子途径和既往脂肪变性对单核细胞募集和分化的影响（特别是CCR1， CCR8, CCR9, CX3CR1； apoe缺陷小鼠的西方饮食脂肪变性模型）；3. apap诱导的肝损伤中巨噬细胞分化的分子机制（采用与原代肝细胞亚群精心设计的体外共培养装置）；4. 通过创新的特异性药物抑制剂（一种CCL2抑制rna适体/ Spiegelmer以及一种小分子CCR2/CCR5抑制剂，在进展和消退期间给药）阻断CCR2和CCR2配体CCL2的治疗意义；5. 人类急性肝衰竭发病机制的翻译方法（通过多色FACS和基于纳米串的基因表达模式表征人类肝脏样本，并与小鼠模型数据进行全面比较）。总之，我们将阐明不同的单核细胞/巨噬细胞群体对apap诱导的ALF的贡献，并探索治疗人类急性肝衰竭的治疗意义。

Liver damage resulting from an overdose of acetaminophen (paracetamol, APAP) is one of the leading causes of acute liver failure (ALF) in humans, a life-threatening conditions oftentimes requiring liver trans-plantation. While the initial hepatocyte necrosis due to APAP toxicity can be therapeutically ameliorated using N-acetylcysteine, the outcome of APAP injury at later stages is critically determined by a massive inflammatory reaction. In experimental models of ALF as well as in patients, different macrophage subsets, derived from resident Kupffer cells and infiltrating monocytes, can be found in the liver. The working hypothesis is that macrophage heterogeneity functionally impacts the outcome of APAP-related and non-APAP-related ALF and that interference with the chemokine-mediated recruitment can ameliorate their contribution to liver damage. In this proposal, we will investigate the dynamics and differentiation of macrophage subpopulations as well as the functional involvement of the chemokine receptor CCR2 (and of alternative pathways) in APAP-induced and other models of acute liver injury. The therapeutic potential of blocking CCL2, the main CCR2 ligand, and of CCR2 itself will be explored using innovative pharmacological inhibitors in this mouse model and thus enables translational approaches for clinical applications. Specific aims are: 1. Characterization and dynamics of macrophage subsets and CCR2-dependent inflammation in APAP-induced liver injury (using transgenic mouse strains in three acute liver injury models, intravital multiphoton microscopy imaging of liver for CCR2+ monocytes, extensive phenotyping by Nanostring-based multiplex gene analyses and functional validation by adoptive transfers); 2. exploration of alternative chemokine pathways and effects of pre-existing steatosis for monocyte recruitment and differentiation (specifically CCR1, CCR8, CCR9, CX3CR1; Western-diet steatosis model in ApoE-deficient mice); 3. molecular mechanisms of macrophage differentiation in APAP-induced liver injury (employing elaborate co-culture in vitro set-ups with primary hepatic cell subsets); 4. investigating therapeutic implications by blocking CCR2 and the CCR2 ligand CCL2 by innovative specific pharmacological inhibitors (an CCL2 inhibiting RNA-aptamer / Spiegelmer as well as a small molecular CCR2/CCR5 inhibitor; administration during progression and resolution); 5. translational approaches to the pathogenesis of human acute liver failure (by characterizing human liver samples by multicolor FACS and Nanostring-based gene expression pattern and comprehensive comparisons to the mouse model data). Collectively, we will shed light on the contribution of the diverse monocyte/macrophage populations on APAP-induced ALF and explore therapeutic implications for the treatment of acute liver failure in humans.