Alcohol, ROS, and Macrophage Epigenetics

描述（由申请人提供）：乙醇是美国最常见的滥用物质，也是感染的重要危险因素，如细菌性肺炎，这是酗酒者死亡的主要原因。我们和其他人已经积累了大量证据，表明急性乙醇诱导巨噬细胞肿瘤坏死因子α (TNF)分泌抑制，从而导致免疫抑制。然而，慢性乙醇与刺激TNF反应的增强有关，这与肝损伤有关。巨噬细胞系和Kupffer细胞的初步数据表明，慢性EtOH通过氧化还原依赖的表观遗传机制增加了对EtOH的TNF转录。部分原因是NF-kB核易位增加。然而，使用染色质免疫沉淀法的初步研究也显示AP-1家族成员FosB和干扰素调节-3与TNF启动子的结合增加，这种结合对增强TNF转录至关重要。此外，初步数据表明，慢性乙醇也会导致tgf - β抑制tnf - α转录的缺陷，部分原因是慢性乙醇环境下Smad3/4核易位缺陷。

DESCRIPTION (provided by applicant): Ethanol is the most common substance of abuse in the US and an important risk-factor for infections such as bacterial pneumonias which are a leading cause of mortality in alcoholics. We, and others, have accumulated a body of evidence that acute ethanol induces suppression of macrophage tumor necrosis factor-alpha (TNF) secretion, which leads to immunosuppression. Chronic ethanol however, has been associated with an augmentation of stimulated TNF responses, which is associated with liver injury. Preliminary data in macrophage cell lines as well as Kupffer cells has identified that chronic EtOH trough a redox dependent epigenetic mechanism augments TNF transcription in response to EtOH. In part this is due to increase nuclear translocation of NF-kB. However preliminary studies using chromatin immunoprecipitation assays also show increased binding of the AP-1 family member FosB and interferon regulatory-3 to the TNF promoter and this binding is critical for augmented TNF transcription. Moreover, preliminary data suggest that chronic ethanol also results in defective TGF-beta repression of TNF-alpha transcription in part due to defective Smad3/4 nuclear translocation in the setting of chronic ethanol. Based on these data, we hypothesize that chronic ethanol exposure results in increased TNF transcription in macrophages by altering the cellular redox state which results in increased binding of both AP-1 and IRF-3 to the TNF promoter as well as reducing the nuclear level of Smad 3 and 4 which function as a TNF represser. We will test this hypothesis with the following Specific Aims. 1.1. Our hypothesis predicts that chronic ethanol results in a redox-dependent increase in AP-1 and IRF-3 binding to the human TNF promoter resulting in increased transcription of the TNF gene. 2. Investigate the hypothesis that loss of repression by Smad 3 and 4 contributes to increased TNF production by chronic ethanol. 3. Investigate the contributions of AP-1, Trif/IRF-3, and Smad 3 and 4 in regulating increased mononuclear cell TNF production in a mouse model of chronic ethanol. By understanding the complex regulation of ethanol on TNF transcription, we hope to advance the understanding of ethanol's effect on the immune system and enhance potential therapeutic strategies for ethanol related diseases.