Hepatocyte-derived extracellular vesicles in alcoholic liver disease

酒精性肝病(ALD)在美国仍然是一种毁灭性的疾病，许多 全球死亡率估计每年超过70万的其他国家。慢性乙醇 消耗导致肝细胞中的脂肪堆积及其细胞器应激导致 ALD进展过程中的炎症和纤维化。肝细胞与非肝细胞之间的串扰 实质细胞-包括肝巨噬细胞(HMS)和肝星状细胞(HSCs)-是 对这一进程至关重要。然而，涉及的分子机制和信号转导途径。 脂质过载的肝细胞和非实质细胞之间的串扰仍然存在 不完全理解。特别是，这种串扰促进或 调节从慢性无症状酒精性脂肪性肝炎(ASH)到致命性酒精性脂肪肝的转变 肝炎(AH)是设计有效的新疗法来治疗这种毁灭性疾病的中心问题 疾病。虽然我们专注于细胞间通讯的研究，但最近我们揭示了 受损的肝细胞释放细胞外小泡(EV)，这些EV在 ALD小鼠模型中的血液。电动汽车有效地内化到靶细胞中，并将其 包括miRNA在内的货物。后者是电动汽车中封装miRNAs的关键机制 (EV-miRNAs)作为“功能性胞外RNAs”在靶体内调节蛋白质翻译 细胞。电动汽车还包含无菌危险信号，称为损害相关分子模式 (潮湿)。我们发现来自AH小鼠的肝细胞来源的EVS富含 有助于激活炎症过程的线粒体DNA(MtDNA)。此外，我们的 比较慢性(C)ASH小鼠肝脏的RNA-SEQ数据的通径分析， EV被认为是最显著的上调途径之一。基于这些结果，我们 提出核心假设，即具有数量和质量不同货物的电动汽车是 急性肝炎患者受损肝细胞释放与之前的CART相比，诱导独特的细胞串扰 在AH病理表型的发生中起重要作用。我们还假设血浆EV分析 用作液体肝活检，为ALD严重程度的诊断和分期提供条形码。至 调查这些假设我们的建议有以下具体目标。1)确定 EVS及其来自肝细胞的货物作为条形码的作用 在小鼠模型和人类ALD中无症状的现金到急性白血病。2)剖析其运行机制 参与了EV介导的细胞到细胞的通讯，实现了从现金到AH的过渡。致信地址 在这些核心问题上，我们组建了一个拥有EV生物学专业知识的MPI调查团队， ALD病理学、独特动物模型的发展、人类ALD和RNA疗法。

Alcoholic liver disease (ALD) continues to be a devastating disease in the United States and many other countries with the global mortality estimated to exceed 0.7 million per year. Chronic ethanol consumption results in lipid accumulation in hepatocytes and their organelle stress leading to inflammation and fibrosis in the progression of ALD. The crosstalk between hepatocytes and non- parenchymal cells - including hepatic macrophages (HMs) and hepatic stellate cells (HSCs) - is crucial to this process. However, the molecular mechanisms and signaling pathways involved in the crosstalk between lipid overloaded hepatocytes and non-parenchymal cells, remain incompletely understood. In particular, the mechanisms by which this crosstalk facilitates or regulates a transition from chronic asymptomatic alcoholic steatohepatitis (ASH) to fatal alcoholic hepatitis (AH) is a central issue for designing efficacious novel treatments for this devastating disease. While focused on the investigation of cell-to-cell communication we recently revealed that damaged hepatocytes release extracellular vesicles (EVs) and these EVs circulate in the blood in mouse models of ALD. EVs are efficiently internalized into target cells and transfer their cargo including miRNAs. The later is a key mechanism by which encapsulated miRNAs in EVs (EV-miRNAs) serve as “functional extracellular RNAs” to regulate protein translation in target cells. EVs also contain sterile danger signal known as damage-associated molecular patterns (DAMPs). We found that EVs derived from hepatocytes from AH mice are enriched in mitochondrial DNA (mtDNA) that contribute to activation of an inflammatory process. Further, our pathway analysis of RNA-seq data comparing AH vs. preceding chronic (c)ASH mouse livers, identifies EV as one of the most significantly upregulated pathways. Based on these results, we propose the central hypothesis that EVs with a quantitatively and qualitatively distinct cargo are released from damaged hepatocytes in AH vs. preceding cASH to induce unique cellular crosstalk in the genesis of the AH pathologic phenotype. We also hypothesize that plasma EV analysis serves as a liquid liver biopsy providing a barcode for diagnosis and staging of ALD severity. To investigate these hypotheses our proposal has the following SPECIFIC AIMS. 1) Determine the role of EVs and their cargo derived from hepatocytes as barcodes for a transition from asymptomatic cASH to AH in murine models and human ALD. 2) Dissect the mechanisms involved in EV-mediated cell-to-cell communication in the cASH to AH transition. To address these central issues, we have put together a MPI investigative team with expertise in EV biology, ALD pathology, development of unique animal models, human ALD, and RNA therapeutics.