The role of dietary unsaturated fat and inflammasome in alcoholic liver disease

 描述(申请人提供)：酒精性肝病(ALD)是世界上发病率和死亡率的主要原因。它每年影响全球数百万患者。虽然 ALD的发病机制已取得实质性进展，但ALD发生发展的具体机制尚不清楚。重要的是，没有FDA批准的针对ALD任何阶段的治疗方法。我们实验室和其他实验室最近的研究表明，在ALD的实验动物模型中，富含亚油酸(LA)的饮食不饱和脂肪与饮食饱和脂肪相比，加剧了酒精介导的肠道通透性和肝脏损伤。此外，我们的初步数据显示循环氧化LA代谢物(OXLAM)水平升高，特别是9-和13-羟基十八碳二烯酸(9-和13-HODES)，伴随着肝脏12/15脂氧合酶(12/15-LO)的上调，12/15-LO是参与LA氧化的关键酶。这些发现提供了OXLAM参与ALD发病的初步证据，OXLAM是瞬时受体潜力香草素1(TRPV1，V亚家族成员1)的天然配体。TRPV1是一种配体门控型非选择性阳离子通道，对钙离子有很高的通透性。最近的一些研究表明，细胞内钙离子在炎性小体激活中起着关键作用。NLRP3型炎症体激活可释放高度致炎细胞因子白介素1β(IL-1β)和白介素18(IL-18)，是酒精性肝病重要的促炎反应。然而，ALD中炎性小体启动和激活的分子机制尚不完全清楚。我们的中心假设是，饮食中的不饱和脂肪(富含亚油酸)通过氧化的亚油酸代谢产物促进肝脏炎症体的激活，加剧了酒精介导的肝脏炎症和损伤。我们认为OXLAM/TRPV1/Ca~(2+)信号通路是炎性小体激活的上游机制。为了解决我们的假设，我们提出了以下具体目标。目的1.探讨氧化亚油酸代谢产物(OXLAM)及12/15-LO介导的亚油酸氧化途径在ALD发生发展中的作用。目的2.在ALD动物模型中评估肝脏炎性小体激活是否由OXLAM-TRPV1-钙离子途径介导。目的3.探讨12/15-LO、TRPV1和OXLAMs在酒精性肝炎炎症小体激活中的作用。该提案将更好地理解酒精与饮食的相互作用，以及导致酒精引起的肝脏炎症和损伤的分子机制。这项研究将导致确定治疗ALD的新治疗靶点和潜在的饮食干预措施，以及 提供一种饮食机制来解释为什么只有一些酗酒者会患上临床上重要的ALD。将采用体外、体内动物(功能的获得和丧失)和人体研究相结合的方法。

 DESCRIPTION (provided by applicant): Alcoholic liver disease (ALD) is a major cause of morbidity and mortality in the world. It affects millions of patients worldwide each year. Although substantial progress has been made in ALD pathogenesis, the specific mechanisms responsible for ALD development and progression remain poorly understood. Importantly, there is no FDA approved therapy for any stage of ALD. Recent studies from our laboratory and others have demonstrated that dietary unsaturated fat rich in linoleic acid (LA) exacerbated alcohol- mediated intestinal permeability and liver injury as compared with dietary saturated fat in an experimental animal model of ALD. In addition, our preliminary data show elevated levels of circulating oxidized LA metabolites (OXLAMs), specifically 9- and 13-hydroxy-octadecadienoic acids (9- and 13-HODEs), concomitant with the up-regulation of hepatic 12/15 lipoxygenase (12/15-LO), the key enzyme involved in the oxidation of LA. These findings provide initial evidence that OXLAMs, which are natural ligands to the transient receptor potential vanilloid 1 (TRPV1, subfamily V member 1), contribute to the pathogenesis of ALD. TRPV1 is a ligand-gated non-selective cation channel with high permeability for Ca2+. A number of recent studies have shown a critical role for intracellular Ca2+ in inflammasome activation. NLRP3 Inflammasome activation with release of highly pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18) is an important pro-inflammatory response in ALD. However, the molecular mechanisms contributing to the inflammasome priming and activation in ALD are not fully identified. Our central hypothesis is that dietary unsaturated fat (linoleic acid enriched) exacerbates alcohol-mediated liver inflammation and injury via oxidized linoleic acid metabolites that facilitate hepatic inflammasome activation. We propose that the OXLAM/TRPV1/Ca2+ signaling pathway is an upstream mechanism of inflammasome activation. To address our hypothesis, we propose the following specific aims. Aim 1. Determine the role of oxidized linoleic acid metabolites (OXLAMs) and the 12/15-LO-mediated pathway of linoleic acid oxidation in the development and/or progression of ALD. Aim 2. Assess whether hepatic inflammasome activation is mediated by an OXLAM-TRPV1-Ca2+ pathway in an animal model of ALD. Aim 3. Determine the potential role of 12/15-LO, TRPV1 and OXLAMs in inflammasome activation in human Alcoholic Hepatitis. The proposal will provide a better understanding of alcohol-diet interactions and molecular mechanisms contributing to the pathogenesis of alcohol-induced liver inflammation and injury. The study will lead to identification of new therapeutic targets and potential dietary interventions for treating ALD, and provide a dietary mechanism to explain why only some heavy drinkers develop clinically important ALD. A combination of in vitro, in-vivo animal (gain and loss of function) and human studies will be employed.