Regulation of cellular senescence by non-coding RNAs in alcoholic liver injury

项目总结/摘要 酒精性肝病（ALD）是美国最常见的慢性肝损伤形式之一。 慢性乙醇消耗导致肝脏中的有毒代谢物和增加的细胞应激， 炎症和肝损伤。事实上，细胞衰老发生在肝细胞、胆管细胞和 非实质细胞-包括肝星状细胞（HSC）-在酒精代谢过程中至关重要。 尽管脂肪变性在疾病过程中的重要性， 代谢，甚至比乙醇本身更有毒，仍然知之甚少。小分子非蛋白编码 RNA（miRNAs）通过调节基因表达在多种细胞途径中发挥核心作用。确实有 现在有令人信服的证据表明酒精代谢与ALD细胞衰老之间存在关联。 尽管综合证据支持miRNAs与酒精性肝病之间的联系，但仍存在关键的 需要确定乙醇依赖性miRNAs促进酒精性肝的潜在机制 损伤在缺乏这种知识的情况下，开发新的基于机制的预防性或 ALD的治疗策略仍然有限。我们的长期目标是确定 有助于酒精诱导的肝病，因此基于新机制的临床有效预防或 可以制定治疗策略。该提案的目的是确定乙醇依赖性如何 miRNAs介导酒精性肝病进展中的细胞代谢和衰老。我们的中央 假设乙醇依赖性miRNAs通过调节细胞凋亡促进酒精性肝损伤， HSC、肝细胞和胆管细胞中的代谢和衰老。这一假设是由 根据现有的文献和我们自己的初步数据。拟议研究的基本原理是 对小的非编码RNA介导的细胞代谢的功能作用的机制理解 酒精性肝损伤中的衰老可能有助于建立一个概念框架， 预防或治疗酒精性肝病的干预措施。提出了以下两个具体目标： 首先，我们将识别参与乙醇代谢、细胞存活和细胞凋亡的miR-34 a下游靶点。 衰老第二，我们将确定microRNA介导的细胞衰老对酒精依赖的影响。 体内衰老加速小鼠和miR-34 a敲除小鼠的肝损伤。完成时 提出的研究，这是我们的期望，已确定的基本机制miRNAs调节 肝细胞代谢和不同肝细胞系的不同衰老特性（目的1）。我们还 预期在酒精性肝损伤的恢复过程中具有特定miRNA的量化治疗效果 (Aim 2）。这些结果预计将产生重要的积极影响，因为一个机械的 了解ncRNA在酒精介导的肝脏疾病中的作用可能为研究ncRNA在肝脏疾病中的作用提供基础。 开发基于证据的临床有用的方法来治疗或预防ALD。

PROJECT SUMMARY/ABSTRACT Alcoholic liver disease (ALD) is one of the most common forms of chronic liver injury in the United States. Chronic ethanol consumption results in toxic metabolites in the liver and increased cell stress leading to inflammation and liver damage. Indeed, the cellular senescence occurred in hepatocytes, cholangiocytes and non-parenchymal cells - including hepatic stellate cells (HSCs) - is crucial to alcoholic metabolizing process. Despite the importance of steatosis in the disease process, the molecular pathways mediating ethanol metabolism, which is even more toxic than ethanol itself remain poorly understood. Small non-protein-coding RNAs (miRNAs) play a central role in various cellular pathways by regulating gene expression. Indeed, there is now compelling evidence for an association between ethanol metabolism and cellular senescence in ALDs. Although the combined evidence supports a link between miRNAs and alcoholic liver disease, there is a critical need to determine the underlying mechanism whereby ethanol-dependent miRNAs promote alcoholic liver injury. In the absence of such knowledge, the promise of developing novel mechanism-based preventive or treatment strategies for ALD will remain limited. Our long-term goal is to determine underlying mechanisms contributing to alcohol-induced liver disease so that new mechanism-based clinically effective prevention or treatment strategies can be developed. The objective for this proposal is to determine how ethanol-dependent miRNAs mediate cell metabolism and senescence in the progression of alcoholic liver diseases. Our central hypothesis is that ethanol-dependent miRNAs contribute to alcoholic liver injury through regulation of cellular metabolism and senescence in HSCs, hepatocytes and cholangiocytes. This hypothesis was formulated based upon the existing literature and our own preliminary data. The rationale for the proposed research is that a mechanistic understanding of the functional role of small non-coding RNAs mediated cell metabolism and senescence in alcoholic liver injury is likely to contribute to a conceptual framework whereby new targeted interventions to prevent or treat alcohol-induced liver disease. The following two specific aims are proposed: First, we will identify the downstream targets of miR-34a that involve in ethanol metabolism, cell survival and senescence. Second, we will determine the effects of microRNA mediated cellular senescence on alcoholic liver injury in senescence accelerated mice and miR-34a knockout mice in vivo. At the completion of the proposed research, it is our expectation to have determined fundamental mechanisms of miRNAs-regulated hepatic cell metabolism and different senescence properties in different hepatic cell lines (Aim 1). Further, we anticipate having quantified therapeutic effects of specific miRNAs during the recovery of alcoholic liver injury (Aim 2). These results are expected to have an important positive impact because a mechanistic understanding of the role ncRNAs play in alcohol-mediated liver disease is likely to provide a foundation for the development of evidence-based clinically useful approaches to treat or prevent ALD.