Regulation of Innate Immunity and Inflammation Through Nuclear Reprogramming

 说明： 退伍军人中的炎症性疾病以多种方式出现，从感染，特别是伤口感染，到因执行任务所造成的压力而加剧的代谢紊乱。他们的后遗症从急性的、危及生命的微生物炎症到慢性的、虚弱的代谢性炎症。身体对微生物(细菌、真菌、病毒)和代谢(过量的胆固醇、甘油三酯、尿酸)侮辱的反应是由先天免疫和炎症调节的。无论刺激的来源是什么，这种反应一开始都是有益的，但很快就会在多个器官中引发有害的炎症和代谢变化。对微生物和新陈代谢刺激的先天免疫反应的共同联系是细胞内信号到细胞核，在那里基因组被重新编程以维持炎症。然而，炎症和代谢信号在疾病发展过程中的相互关系还知之甚少。我们已经开发出核运输修饰物(NTM)，这是一种穿透性多肽，旨在抑制细胞内的核适配器蛋白Importin Alpha 5(Impα5)和Importin Beta 1(Impβ1)分别向细胞核传递炎症和脂质控制信号。NTM通过靶向Impα5介导的应激反应转录因子(SRTF)的核运输来减轻炎症，例如核因子kappaB，炎症和免疫的主要调节因子。NTMS还抑制Impβ1介导的甾醇调节元件结合蛋白转录因子的核运输，该转录因子是胆固醇、甘油三酯和脂肪酸合成和摄取的主要调节者。在相关的微生物、自身免疫和代谢性疾病的临床前模型中，NTMS已经有效地改善了炎症过程。我们假设微生物炎症主要依赖于Impα5途径，而代谢性炎症需要Impα5和Impβ1两种途径。我们进一步假设，SRTF/Impα5和SREBP/Impβ1信号通路之间的相互作用使脂肪过多的个体更容易受到微生物的侮辱。我们将应用新设计和生产的NTM作为独特的探针，独立地针对Impα5或Impβ1，并分析它们所介导的两条途径。我们将使用基于细胞的分析和临床前模型，研究由一种强有力的促炎微生物毒力因子细菌内毒素或高脂饮食诱导的易患动脉粥样硬化的小鼠品系的炎症。有了这些独特的探针，目标1将定义这两个不同的核运输信号通路在微生物炎症中的作用，而目标2将定义它们在代谢性炎症中的作用。目的比较分析SRTf/Impα5和SREBP/Impβ1信号通路在肥胖人群内毒素超敏反应中的作用。总而言之，我们对核运输的机制研究将产生急需的信息，即对微生物和新陈代谢损伤的先天免疫反应，这些信息受到SRTF和SREBPs的调节。

 DESCRIPTION: Inflammatory diseases in the Veteran population arise in many ways, ranging from infections, especially of wounds, to metabolic disorders aggravated by stress from tours of duty. Their sequelae range from acute, life-threatening microbial inflammation to chronic and debilitating metabolic inflammation. The body's response to microbial (bacteria, fungi, viruses) and metabolic (excess cholesterol, triglycerides, uric acid) insults is mediated by innate immunity and inflammation. Whatever the source of the stimulus, the response is at first beneficial, but can soon induce harmful inflammatory and metabolic changes in multiple organs. The common nexus of innate immune responses to microbial and metabolic stimuli is intracellular signaling to the nucleus, where the genome is reprogrammed to perpetuate inflammation. However, the interrelation of inflammatory and metabolic signaling in development of disease is poorly understood. We have developed nuclear transport modifiers (NTMs), cell-penetrating peptides designed to inhibit the intracellular nuclear adaptor proteins known as importin alpha 5 (Imp α5) and importin beta 1 (Imp β1) from shuttling both inflammatory and lipid-controlling signals, respectively, to the nucleus. NTMs reduce inflammation by targeting Imp α5-mediated nuclear transport of Stress-Responsive Transcription Factors (SRTFs), exemplified by nuclear factor kappa B, the master regulator of inflammation and immunity. NTMs also inhibit Imp β1-mediated nuclear transport of Sterol Regulatory Element-Binding Protein (SREBP) transcription factors, the master regulators of cholesterol, triglyceride, and fatty acid syntheses and uptake. NTMs have been effective in ameliorating the inflammatory process in relevant preclinical models of microbial, autoimmune, and metabolic diseases. We hypothesize that microbial inflammation is dependent mainly on the Imp α5 pathway whereas metabolic inflammation requires both Imp α5- and Imp β1-mediated pathways. We further hypothesize that cross-talk between the SRTF/Imp α5 and SREBP/Imp β1 signaling pathways predisposes individuals with excessive fat to be more susceptible to microbial insults. We will apply newly designed and produced NTMs as unique probes to independently target Imp α5 or Imp β1 and analyze the two pathways they mediate. We will employ cell-based assays and preclinical models of inflammation induced by a potent proinflammatory microbial virulence factor, bacterial endotoxin, or by a High Fat Diet in atherosclerosis-prone mouse strains. With these unique probes already in hand, Aim 1 will define the role of these two distinct nuclear transport signaling pathways in microbial inflammation, while Aim 2 will define their role in metabolic inflammation. Aim 3 will analyze the comparative roles of SRTF/Imp α5 and SREBP/Imp β1 signaling pathways in development of hypersensitivity to endotoxin in individuals with excessive fat. Cumulatively, our mechanistic studies of nuclear transport will yield much-needed information about innate immune responses to microbial and metabolic insults that are regulated by SRTFs and SREBPs.