Alcohol disrupts TLR4 signaling in lipid rafts

酒精会破坏脂筏中的 TLR4 信号传导

• 批准号: 7498553
• 负责人: Angela Dolganiuc
• 金额: $ 19.3万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-20 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7498553
• 关键词: Acute; Adaptor Signaling Protein; Affect; Alcohol consumption; Alcohols; Antibodies; Attenuated; CD14 Antigen; CD14 gene; CD32 Antigens; CD36 gene; CXCR4 Receptors; CXCR4 gene; Cell Adhesion Molecules; Cell model; Cells; Cellular Membrane; Cholesterol; Chronic; Clinical; Complement Receptor; Complex; Confocal Microscopy; Cyclophosphamide/Fluorouracil/Prednisone; Data; Detergents; Disruption; Endotoxemia; Event; FCGR3B gene; Fc Receptor; Fluorescence Resonance Energy Transfer; Heat shock proteins; Human; ITGAM gene; ITGB2 gene; Immune response; Immunity; In Vitro; Infection; Inflammatory; Investigation; Lead; Lipopolysaccharides; Liver; Lung diseases; Membrane; Membrane Microdomains; Modality; Modeling; Molecular; Myelogenous; Pathway interactions; Predisposition; Production; Proteins; Proteomics; Receptor Signaling; Recruitment Activity; Resistance; Septic Shock; Signal Transduction; TLR4 gene; Therapeutic; Toll-like receptors; Western Blotting; Work; alcohol abuse therapy; alcohol effect; alcohol exposure; base; cytokine; design; flotillin; improved; in vivo; member; monocyte; prevent; problem drinker; receptor; scavenger receptor; toll-like receptor 4

DESCRIPTION (provided by applicant): Alcohol consumption is associated with increased susceptibility to infections and impaired immune responses, the mechanisms if which are not well understood. LPS, a major component of bacterial wall, is recognized by toll-like receptor (TLR) 4 and accessory molecule CD14 and triggers a variety of intracellular events that culminates in the production of pro-inflammatory cytokines. Our previous work showed that in monocytes, acute alcohol impairs bacterial lipopolysaccharide (LPS)-induced cellular activation via inhibition of NF¿B pathway to result in low pro-inflammatory cytokines production. Recent studies suggest that LPS triggers formation of a large "signalosome" - a complex of cellular receptors, including TLR4, CD14, FcR, CD36, CD55, CD11b, CD18, Hsp70, Hsp90, and CXCR4. Formation of signalosome requires rigid cholesterolrich membrane platforms, called membrane rafts. We recently identified that disruption of membrane rafts via cholesterol depletion prevents LPS-induced cell activation. Further, we identified that alcohol prevents TLR4 association with rafts. Based on preliminary data, we hypothesize that alcohol may affect the early events of LPStriggered cell activation. We postulate that inhibition cell activation by alcohol depends on the complexity of signal events that take place at the level of membrane rafts. We further hypothesized that acute alcohol targets the LPS-triggered recruitment of signalosome into lipid rafts and thus prevents cell activation. Specifically, we propose that alcohol disrupts the formation of the "signalosome". The Specific Aim of this proposal is to determine the influence of alcohol on the integrity of the TLR4 receptor complex (TLR4, CD14, MD2, MyD88, signalosome members) A) by exploring the colocalization with membrane rafts; B) evaluating the association with detergent-resistant membranes (DRMs); C) detecting acquisition/loss of proteins within the TLR4 receptor complex D) studying the formation of TLR4 multimers. Results from these studies should delineate the early molecular events that lead to impaired LPS-induced cellular activation after acute exposure to alcohol. Investigation of the early steps of LPS signaling may identify strategies for interfering with the effects of LPS and design therapeutic approaches for improving immunity against infections.

描述（由申请人提供）：饮酒与感染易感性增加和免疫反应受损有关，但其机制尚不清楚。 LPS 是细菌壁的主要成分，可被 Toll 样受体 (TLR) 4 识别并 辅助分子 CD14 并触发多种细胞内事件，最终产生促炎细胞因子。我们之前的工作表明，在单核细胞中，急性酒精通过抑制 NF¿B 通路来损害细菌脂多糖 (LPS) 诱导的细胞活化，导致促炎细胞因子的产生减少。最近的研究表明，LPS 会触发大型“信号体”的形成，这是一种细胞受体复合物，包括 TLR4、CD14、FcR、CD36、CD55、CD11b、CD18、Hsp70、Hsp90 和 CXCR4。信号体的形成需要刚性的富含胆固醇的膜平台，称为膜筏。我们最近发现，通过胆固醇消耗破坏膜筏可以防止脂多糖诱导的细胞活化。 此外，我们发现酒精会阻止 TLR4 与筏的结合。根据初步数据，我们假设酒精可能影响 LPS 触发的细胞激活的早期事件。我们假设酒精对细胞激活的抑制取决于膜筏水平上发生的信号事件的复杂性。我们进一步假设，急性酒精会靶向 LPS 触发的信号体募集到脂筏中，从而阻止细胞激活。具体来说，我们认为酒精会破坏“信号体”的形成。该提案的具体目标是通过探索与膜筏的共定位来确定酒精对 TLR4 受体复合物（TLR4、CD14、MD2、MyD88、信号体成员）完整性的影响。 B) 评估与耐去污剂膜 (DRM) 的关联； C) 检测 TLR4 受体复合物内蛋白质的获得/丢失 D) 研究 TLR4 多聚体的形成。这些研究的结果应该描述了急性暴露于酒精后导致 LPS 诱导的细胞活化受损的早期分子事件。对 LPS 信号传导早期步骤的研究可能会确定干扰 LPS 作用的策略，并设计提高感染免疫力的治疗方法。