Diabetes and Inflammation During Infection

项目总结/摘要 100多年来，糖尿病一直被认为是一种免疫抑制疾病。相反，我们 假设相反的情况是正确的：糖尿病患者革兰氏阴性菌感染的不良结局是由于 糖尿病驱动的免疫增强，因为：1）Toll样受体4（TLR 4）在感染期间具有抗保护作用 由革兰氏阴性菌引起; 2）在革兰氏阴性菌中，响应于LPS的TLR 4炎性输出加重， 糖尿病患者; 3）我们最近发现，阻断晚期糖基化终产物（AGE）与其受体的结合， 受体（CRP 1）改善糖尿病小鼠对革兰氏阴性菌感染的过度易感性;和4）两者 TLR 4和MyD 88可以通过MyD 88进行信号传导，这表明MyD 88/TLR 4协同作用的机制。 我们的中心假设-糖尿病增强而不是抑制先天反应， 感染-具有新颖的翻译影响。特别是，免疫调节，以改善结果 糖尿病宿主的感染应该试图扭转一个100年的格言：抑制先天反应 我们试图：1）确定I. V.和肺组织中IL-6/TLR 4信号传导的关系， 革兰氏阴性菌引起的感染; 2）使用有前途的 化合物使免疫反应正常化，降低发病率和死亡率。我们的目标是： 具体目标1：确定MyD 88与TRIF信号传导在糖尿病患者静脉注射和肺部感染期间的作用 小鼠假设：MyD 88是介导革兰氏阴性菌感染易感性的信号通路。 糖尿病小鼠，因为它可以独立的信号TLR 4和TLR 4，创造潜在的协同炎症， 状态。方法：MyD 88和TRIF是负责TLR 4信号传导的主要途径。我们发现 TLR 4的破坏能明显但不完全地保护糖尿病小鼠免受A.可能是鲍曼不动杆菌感染 这是因为通过MyD 88的残余信号传导由MyD 88引起的。为了定义驱动结果的途径，将比较 存活率、脓毒症生物标志物和I. V.期间的细菌负荷以及野生型中的肺部感染（阳性）。对照）与 TLR 4-KO（阴性）对照）、MyD 88-KO和TRIF-KO小鼠，其是糖尿病或用RAGE激动剂治疗。 具体目标2：确定目前在药物中的抑制剂组合的潜力 在革兰氏阴性菌感染期间， 糖尿病宿主假设：同时抑制TLR 4和TLR 4将提供上级结果 免受感染方法：我们将比较非糖尿病患者的生存率、脓毒症生物标志物和细菌负荷。 （neg.对照）与糖尿病小鼠静脉内感染或通过肺感染，并用安慰剂（pos.对照）与1） TLR 4拮抗剂; 2）TLR 4拮抗剂;或3）两者的组合。为了确保普遍性，小鼠将 感染了三种耐药细菌：A. baumannii、鲍曼不动杆菌E.大肠杆菌和肺炎克雷伯氏菌。 影响：这些结果将使这些致命感染的免疫疗法得以转化， R 01，以定义下游的糖尿病炎症信号传导和代谢机制。

PROJECT SUMMARY/ABSTRACT For more than 100 years, diabetes has been considered an immune-suppressed condition. In contrast, we hypothesize that the opposite is true: worse outcomes of Gram-negative infection in diabetics are due to diabetes-driven enhanced immunity because: 1) Toll-like receptor 4 (TLR4) is anti-protective during infection caused by Gram negative bacteria; 2) TLR4 inflammatory output in response to LPS is exacerbated in diabetics; 3) we recently found that blocking the binding of Advanced Glycation Endproducts (AGE) to their receptor (RAGE) ameliorated hyper-susceptibility of diabetic mice to Gram-negative infection; and 4) both TLR4 and RAGE can signal via MyD88, suggesting a mechanism for RAGE/TLR4 synergy. Our central premise—diabetes enhances rather than suppresses the innate response to infection—has novel translational impact. Specifically, immunomodulation to improve outcomes of infection in diabetic hosts should seek to reverse a 100 year-old maxim: suppress the innate response rather than enhance it. We seek to: 1) determine the RAGE/TLR4 signaling relationships during I.V. and lung infections caused by Gram-negative bacteria; and 2) develop translational solutions using promising compounds to normalize immune responses, reducing morbidity and mortality. Our Aims are to: Specific Aim 1: Define the role of MyD88- vs. TRIF-signaling during I.V. and lung infection in diabetic mice. HYPOTHESIS: MyD88 is the signaling pathway mediating susceptibility to Gram-negative infection in diabetic mice, since it can independently signal for TLR4 and RAGE, creating potential for synergistic inflamm- ation. Methods: MyD88 and TRIF are the primary pathways responsible for TLR4 signaling. We found that TLR4 disruption markedly but incompletely protected diabetic mice from A. baumannii infection, possibly because of residual signaling via MyD88 by RAGE. To define the pathway driving outcome, will compare survival, sepsis biomarkers, and bacterial burden during I.V. and lung infection in wild type (pos. control) vs. TLR4-KO (neg. control), MyD88-KO, and TRIF-KO mice that are diabetic or treated with a RAGE-agonist. Specific Aim 2: Determine the potential for a combination of inhibitors presently in pharmaceutical development against TLR4 and RAGE to alter outcomes during Gram-negative bacterial infection in diabetic hosts. HYPOTHESIS: Simultaneous inhibition of TLR4 and RAGE will provide superior outcomes from infection. Methods: We will compare survival, sepsis biomarkers, and bacterial burden in non-diabetic (neg. control) vs. diabetic mice infected I.V. or through the lungs, and treated with placebo (pos. control) vs. 1) a TLR4 antagonist; 2) a RAGE antagonist; or 3) combination of both. To ensure generalizability, mice will be infected with three antibiotic-resistant bacteria: A. baumannii, E. coli, and Klebsiella pneumoniae. IMPACT: These results will enable translation of immune therapies for these deadly infections, and will enable an R01 to define downstream RAGE signaling and metabolic mechanisms driving inflammation in diabetes.