Cold Inducible RNA Binding Protein and Alcohol Induced Neurosuppression

描述(申请人提供)：在药物滥用中，酒精是使用最广泛的物质之一。酗酒影响了1800万人，仅在美国，每年因酒精相关疾病而造成的直接损失就高达270亿美元。过量饮酒与认知功能受损甚至大脑结构恶化有关。脑成像技术对我们了解酗酒的影响及其与人脑功能和结构变化的相关性做出了重大贡献。对大脑葡萄糖代谢的评估是衡量大脑功能的可靠指标。使用正电子发射断层扫描(PET)的研究表明，急性酒精暴露会导致大脑葡萄糖利用率降低，反映出大脑活动的减少。然而， 导致这种神经抑制的分子因素尚未阐明。在这个项目中，我们建议测试一个新的概念，即一种新发现的炎症介质，冷诱导RNA结合蛋白(CIRP)，负责报告的酒精中毒患者神经元活性下降。在我们的初步研究中，我们已经建立了使用先进的、非侵入性和实时的microPET成像技术来监测小鼠的大脑活动。我们的结果表明，酒精中毒导致野生型小鼠脑内葡萄糖代谢显著下降。相比之下，CIRP基因敲除小鼠对急性酒精暴露引起的大脑葡萄糖代谢下降更具抵抗力，这表明CIRP可能介导了中枢神经抑制。此外，在酒精暴露的野生动物中，大脑下丘脑和脑脊液中的CIRP蛋白水平增加。在小胶质细胞(脑巨噬细胞)BV2细胞中，酒精暴露以剂量依赖的方式增加CIRP的mRNA和蛋白的表达及其释放到细胞外基质中。此外，重组小鼠CIRP(RmCIRP)可引起炎症反应和组织损伤。基于这些观察，我们假设酒精中毒增加了大脑CIRP的表达和释放，从而导致大脑活动减少。为了验证这一假说，我们将进一步证实CIRP在酒精暴露后降低中枢神经元活性中的直接作用，并确定酒精诱导脑内CIRP表达的分子机制。这些研究将提供有用的信息，使我们能够准确定位酒精诱导的脑损伤和由CIRP上调介导的中枢神经抑制的机制。 与公共健康相关：在药物滥用中，酒精是使用最广泛的物质。据估计，50%的12岁或12岁以上的美国人每月至少饮酒一次，其中6.8%被认为是酗酒者。长期大量饮酒导致5万多人住院，4%的人死亡。据估计，在美国，与酒精相关的疾病每年造成的直接损失高达270亿美元。我们独特的创新方法将证明一个新的概念，即一种新发现的名为CIRP的炎性介质可能是报道的酗酒者大脑活动减少的原因。这些研究将为酒精诱导的中枢神经抑制的潜在治疗方法提供见解。1

DESCRIPTION (provided by applicant): Among substance abuse, alcohol is one of the most wildly used substances. Alcohol abuse affects 18 million people with a direct cost of $27 billion annually for alcohol-related illnesses in the United States alone. Excessive alcohol ingestion is associated with the impairment of cognitive function and even structural deterioration in the brain. The brain imaging technique has significantly contributed to our understanding of the effect of alcohol abuse and its correlation to functional and structural changes in the human brain. The assessment of brain glucose metabolism is a reliable measure of cerebral function. Studies using positron emission tomography (PET) have indicated that acute alcohol exposure results in lower brain glucose utilization, reflecting a decrease in brain activities. However, the molecular factor responsible for such neurosuppression has not yet been elucidated. In this project, we propose to test a novel concept that a newly-identified inflammatory mediator, cold-inducible RNA-binding protein (CIRP), is responsible for the reported decrease in neuronal activities in alcoholics. In our preliminary study, we have established the use of the advanced, non-invasive, and real-time microPET imaging technology to monitor brain activities in the mouse. Our results showed that alcohol intoxication in wild-type mice produced significant decrease in brain glucose metabolism. In contrast, CIRP knockout mice were more resistant to the decrease in brain glucose metabolism induced by acute alcohol exposure, suggesting CIRP may mediate central neurosuppression. In addition, CIRP protein levels increased in the hypothalamus of the brain and cerebral spinal fluid in alcohol-exposed wild-type animals. In murine microglia (brain macrophages) BV2 cells, alcohol exposure increased CIRP's mRNA and protein expression as well as its release into the extracellular matrix in a dose-dependent manner. Moreover, recombinant murine CIRP (rmCIRP) caused inflammation and tissue injury. Based on these observations, we hypothesize that alcohol intoxication increases brain CIRP expression and release, which cause the reduction of brain activities. To test this hypothesis, we will further confirm the direct role of CIRP in reducing central neuronal activities after alcohol exposure, and to determine the molecular mechanism responsible for alcohol-induced CIRP expression in the brain. These studies should provide useful information that will allow us to pinpoint the mechanism of alcohol-induced brain damage and central neurosuppression mediated by upregulation of CIRP. PUBLIC HEALTH RELEVANCE: Among substance abuse, alcohol is the most wildly used substance. It is estimated that 50% of Americans 12 years or older consume alcohol at least once a month and 6.8% of them are considered as heavy drinkers. Drinking alcohol at high levels for a long term accounts for over 50,000 hospitalizations with 4% deaths. The direct cost of alcohol-related illnesses in the US has been estimated to be $27 billion annually. Our unique and innovative approach will prove the novel concept that a newly-identified inflammatory mediator called CIRP could be responsible for the reported decrease in brain activities in alcoholics. These studies will provide insights into potential therapeutic approaches in alcohol-induced central neurosuppression. 1