Effect of Bacterial Tolerance on TLR4 Signal Transduction

细菌耐受性对 TLR4 信号转导的影响

基本信息

批准号：
8707308
负责人：
ANDREI E MEDVEDEV
金额：
$ 25.88万
依托单位：
UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-09-01 至 2016-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8707308
关键词：
Address Affect American Animal Model Anti-Inflammatory Agents Anti-inflammatory Area Autoimmune Diseases Biological Assay Biological Markers Cells Cessation of life Chemicals Communicable Diseases Cytokine Inducible SH2-Containing Protein Data Deubiquitinating Enzyme Development Dimerization Disease Docking Endotoxins Event Exposure to Family Dasypodidae Funding Gene Silencing Genes Goals Gram-Negative Bacteria Health Host Defense Human IRAK1 gene IRAK4 gene Immune Immunocompromised Host Immunosuppression Incidence Inflammation Inflammatory Interferons Life Ligands Link Lipopolysaccharides MAP3K7 gene Mediating Modeling Molecular National Institute of Allergy and Infectious Disease Pathogenesis Patients Phase Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Polyubiquitination Post-Translational Protein Processing Production Protein Isoforms Protein Tyrosine Phosphatase Public Health RNA Splicing Receptor Signaling Research Role SRC gene Sepsis Septic Shock Signal Pathway Signal Transduction Signaling Molecule Sterility TANK-binding kinase 1 TBK1 gene TLR4 gene TRAF6 gene Testing Toll-Like Receptor Pathway Toll-like receptors Tumor Necrosis Factor Receptor Tyrosine Phosphorylation Ubiquitination adapter protein antimicrobial base chemokine cytokine design health science research human IRF3 protein human TOLLIP protein improved in vivo inhibitor/antagonist inositol-1,4,5-trisphosphate 5-phosphatase insight interferon regulatory factor-3 macrophage microbial monocyte mortality neutrophil novel therapeutic intervention novel therapeutics pathogen prevent programs receptor response secondary infection septic toll-like receptor 4 transcription factor translational study ubiquitin-protein ligase

项目摘要

DESCRIPTION (provided by applicant): Sepsis is a major threat to human health in the US, affecting ~750,000 Americans per year, with an associated mortality rate >28%. Many septic patients develop profound immunosuppression manifested by decreased production of pro-inflammatory cytokines and chemokines. This is highly reminiscent of endotoxin tolerance, a state of re-programming of TLR4 responses after a prior exposure to LPS. Endotoxin tolerance can be used as a model to delineate mechanisms that underlie altered monocyte responses in patients with sepsis. During the period of funding, we have identified new hallmarks of endotoxin tolerance. These include: (i) deficient tyrosine phosphorylation of TLR4 and adapter protein Mal; (ii) suppressed LPS-induced signalosome assembly amongst TLR4, adapter protein TRIF and kinase TBK1; (iii) deficient activation of TBK1 and transcription factor IRF-3; and (iv) increased expression of negative regulators Tollip, IRAK-M, SHIP-1, SOCS-1, SARM, and SIKE. Our preliminary data in THP1 cells and human monocytes show decreased LPS- induced c-Src and Lyn phosphorylation and Lyn-TLR4 interactions; inhibited activation of kinases IRAK4 and TAK-1; impaired K63-linked polyubiquitination of IRAK1 and TRAF-6; suppressed interactions of ubiquitinated IRAK1 with TRAF6 and IKK3; and increased expression of A20, a key deubiquitinating enzyme. Furthermore, we found reduced LPS tolerance induction upon inhibition of protein tyrosine phosphatases or by A20 gene knockdown, indicating a crucial role for altered tyrosine phosphorylation and K63-linked polyubiquitination in tolerance. Based on these data, we hypothesize that LPS tolerance alters post-translational modifications of TLR4, Mal and IRAK kinases and increases levels of negative regulators of TLR signaling, leading to reprogramming of TLR responses through changes in proximal signalosome compositions. This hypothesis will be tested in the following Specific Aims: 1. Identify kinases and phosphatases involved in phosphorylation of TLR4 and Mal and determine the impact of LPS tolerance on their expression and activities; 2. Define mechanisms by which LPS tolerance alters signalosome assembly and activation of proximal adapter-kinase modules; and 3. Elucidate molecular basis of interference in TLR4 signaling by negative regulatory molecules associated with LPS tolerance. These studies will determine new mechanisms responsible for tolerance and identify key intermediates affected. They will lay the groundwork for our future research in animal models of sepsis in vivo and translational studies in septic patients, with the goal of facilitating development of new therapeutic strategies to improve treatments for septic patients. These advances would be of key importance for improving public health in septic patients in the U.S.

描述（由申请人提供）：败血症是美国人类健康的主要威胁，每年影响约75万美国人，相关死亡率> 28％。许多化粪池患者会产生深远的免疫抑制，这表现为促炎性细胞因子和趋化因子的产生降低。这是高度让人联想到内毒素耐受性的，这是先前暴露于LPS后重新编程TLR4反应的状态。内毒素的耐受性可用作描述败血症患者单核细胞反应的基础机制的模型。在资金期间，我们确定了内毒素耐受性的新标志。其中包括：（i）TLR4和衔接蛋白mal的缺乏酪氨酸磷酸化；（ii）在TLR4，衔接蛋白TRIF和激酶TBK1之间抑制了LPS诱导的信号体组装；（iii）TBK1和转录因子IRF-3的激活不足；（iv）增加调节剂Tollip，Irak-M，Ship-1，Socs-1，Sarm和Sike的表达增加。我们在THP1细胞和人类单核细胞中的初步数据显示，LPS诱导的C-SRC和LYN磷酸化以及Lyn-TLR4相互作用降低。抑制激活激活IRAK4和TAK-1； IRAK1和TRAF-6的K63连接多泛素化受损；抑制了泛素化IRAK1与Traf6和Ikk3的相互作用；并增加了A20的表达，这是一种关键的去泛素化酶。此外，我们发现在抑制蛋白酪氨酸磷酸酶或A20基因敲低时，LPS耐受性降低了，这表明酪氨酸磷酸化改变和K63连接的多泛素化在耐受性中至关重要。基于这些数据，我们假设LPS耐受性改变了TLR4，MAL和IRAK激酶的翻译后修饰，并增加了TLR信号传导的负调节剂的水平，从而通过近端信号体成分的变化来重新编程TLR响应。该假设将在以下特定目的中进行检验：1。鉴定参与TLR4和MAL磷酸化的激酶和磷酸酶，并确定LPS耐受性对其表达和活性的影响； 2。定义LPS耐受性改变信号组装和近端适配 - 激酶模块激活的机制；和3。通过与LPS耐受性相关的负调控分子阐明了TLR4信号传导干扰的分子基础。这些研究将确定负责容忍的新机制，并确定受影响的关键中间体。他们将为我们在体内败血症动物模型和化粪池患者的转化研究中为未来的研究奠定基础，目的是促进开发新的治疗策略，以改善化粪池患者的治疗方法。这些进步对于改善美国化粪池患者的公共卫生至关重要。

项目成果

期刊论文数量（16）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

The Asp299Gly polymorphism alters TLR4 signaling by interfering with recruitment of MyD88 and TRIF.

DOI：
10.4049/jimmunol.1200202
发表时间：
2012-05-01
期刊：
Journal of immunology (Baltimore, Md. : 1950)
影响因子：
0
作者：
Figueroa L;Xiong Y;Song C;Piao W;Vogel SN;Medvedev AE
通讯作者：
Medvedev AE

IRAK4 activity controls immune responses to intracellular bacteria Listeria monocytogenes and Mycobacterium smegmatis.

DOI：
10.1002/jlb.2a1117-449r
发表时间：
2018-10
期刊：
Journal of leukocyte biology
影响因子：
5.5
作者：
Pattabiraman G;Murphy M;Agliano F;Karlinsey K;Medvedev AE
通讯作者：
Medvedev AE

Endotoxin Tolerance Inhibits Lyn and c-Src Phosphorylation and Association with Toll-Like Receptor 4 but Increases Expression and Activity of Protein Phosphatases.

DOI：
10.1159/000440838
发表时间：
2016
期刊：
Journal of innate immunity
影响因子：
5.3
作者：
Xiong Y;Murphy M;Manavalan TT;Pattabiraman G;Qiu F;Chang HH;Ho IC;Medvedev AE
通讯作者：
Medvedev AE

Analysis of the functional role of Toll-like receptor-4 tyrosine phosphorylation.

Toll样受体4酪氨酸磷酸化的功能作用分析。