Resistance of Beta 2 Microglobulin Null Mice to Sepsis

描述（由申请人提供）：我们已经令人信服地证明自然杀伤（NK）细胞促进盲肠结扎和穿刺（CLP）引起的败血症的发病机制。然而，在败血症期间促进NK细胞介导的促炎活性的机制尚不清楚。我们最近的研究表明，在clp诱导的脓毒症中，大量CXCR3+ NK细胞离开脾脏进入腹腔。CXCR3配体CXCL9和CXCL10在败血症期间高浓度存在，CXCR3缺陷小鼠对clp诱导的生理功能障碍具有抗性。基于这些观察结果，我们假设CXCR3信号对于NK细胞的募集和激活至关重要，并且CXCR3的作用在脓毒症的发病机制中很重要。以下具体目标将检验这些假设。特异性目的1：确定CXCR3在NK细胞迁移和活化中的重要性及其在CLP诱导脓毒症发病机制中的影响。CXCR3和活化标志物的表达将在感染原发部位的NK细胞和远处组织中进行评估。进一步的研究将评估在CXCR3缺陷小鼠和用中和抗体阻断CXCR3后NK细胞的募集和激活。我们还将确定CXCR3在亚致死性脓毒症、脓毒症诱导的多器官功能障碍和脓毒性休克发病机制中的重要性。具体目标2。确定CXCR3配体（CXCL9和CXCL10）对NK细胞募集和激活的重要性及其在clp诱导脓毒症发病机制中的影响。在感染的原发部位和远端组织中CXCR3配体的细胞来源将被检查。NK细胞的迁移和活化将在CXCR3配体缺陷小鼠或使用中和抗体阻断CXCR3配体后进行研究。通过亚致死性脓毒症、脓毒症诱导的多器官功能障碍和脓毒症休克模型，研究CXCR3配体缺陷小鼠的生理功能、器官损伤和全身炎症。我们还将确定CXCR3配体在对照小鼠或亚致死性脓毒症小鼠中直接诱导脓毒症综合征的能力。具体目标3。clp诱导脓毒症过程中CXCR3轴调节因子的评估这些研究将研究NK细胞对CXCR3配体产生的贡献以及脓毒症期间调节NK细胞CXCR3表达的因素。尽管人们认为lps诱导的巨噬细胞产生CXCL10是受trif依赖性信号调控的，并且需要产生IFN2，但我们认为NK细胞会通过产生IFN3来促进MyD88依赖性CXCL10的产生。本应用程序建议进行研究以解决该断言。进一步的研究将评估旁分泌和自分泌机制对NK细胞CXCR3激活的重要性，以及NK细胞调节CXCR3表达的因素。

DESCRIPTION (provided by applicant): We have convincingly shown that natural killer (NK) cells facilitate the pathogenesis of sepsis caused by cecal ligation and puncture (CLP). However, the mechanisms that contribute to NK cell-mediated pro-inflammatory activity during sepsis are poorly understood. Our recent studies indicate large numbers of CXCR3+ NK cells leave the spleen and enter the peritoneal cavity during CLP-induced sepsis. The CXCR3 ligands CXCL9 and CXCL10 are present at high concentrations during sepsis and CXCR3-deficient mice are resistant to CLP-induced physiologic dysfunction. Based on these observations, we hypothesize that CXCR3 signaling is critical for the recruitment and activation of NK cells and that the actions of CXCR3 are important in the pathogenesis of sepsis. The following specific aims will test these hypotheses. Specific Aim 1: To determine the importance of CXCR3 for NK cell migration and activation as well as its impact on the pathogenesis of CLP- induced sepsis. The expression of CXCR3 and markers of activation will be evaluated on NK cells at the primary site of infection and in remote tissues. Further studies will assess NK cell recruitment and activation in CXCR3-deficient mice and after blockade of CXCR3 with neutralizing antibodies. We will also determine the importance of CXCR3 in the pathogenesis of sublethal sepsis, sepsis-induced multi- organ dysfunction and septic shock. Specific Aim 2. To determine the importance of CXCR3 ligands (CXCL9 and CXCL10) for NK cell recruitment and activation as well as their impact on the pathogenesis of CLP-induced sepsis. The cellular sources of CXCR3 ligands at the primary site of infection and remote tissues will be examined. NK cell migration and activation will be studied in CXCR3 ligand-deficient mice or after blockade of CXCR3 ligands using neutralizing antibodies. Physiological function, organ injury and systemic inflammation will be examined in CXCR3 ligand- deficient mice using models of sublethal sepsis, sepsis-induced multi-organ dysfunction and septic shock. We will also determine the ability of CXCR3 ligands to directly induce the sepsis syndrome in control mice or mice with sublethal sepsis. Specific aim 3. Evaluation of factors that regulate the CXCR3 axis during CLP-induced sepsis. These studies will examine the contributions of NK cells to CXCR3 ligand production and the factors that regulate NK cell CXCR3 expression during sepsis. Although LPS-induced CXCL10 production by isolated macrophages is considered to be regulated by Trif-dependent signaling and require production of IFN2, we propose that NK cells will facilitate MyD88- dependent CXCL10 production through the production of IFN3. Studies are proposed in this application to address that assertion. Further studies will evaluate the importance of paracrine and autocrine mechanisms for NK cell CXCR3 activation and the factors that regulate CXCR3 expression by NK cells. PUBLIC HEALTH RELEVANCE: We have convincingly shown that natural killer (NK) cells facilitate the pathogenesis of sepsis. The chemokine receptor CXCR3 is known to regulate NK cell functions in some disease models. Based on our recent research, we hypothesize that CXCR3 signaling is critical for the recruitment and activation of NK cells during sepsis and that blockade of CXCR3 will improve outcome in septic animals.