Role of CD40 in Sepsis-Induced Lung Injury

描述(由申请人提供)： 急性肺损伤(ALI)是一种主要的健康问题，其特征是液体渗入肺泡并释放促炎细胞因子。它通常是全身炎症过程的结果，包括败血症、创伤、出血和胰腺炎。采用盲肠结扎穿孔(CLP)脓毒症模型，研究细胞表面分子CD40在小鼠ALI发生发展中的作用。我们现在报道，CLP在18小时内产生肺毛细血管渗漏、间质炎症细胞浸润和30%的死亡率。CD40缺失的匹配小鼠的肺部炎症显著减轻，18小时内死亡率为0%。CD40突变还显著降低CLP后血清和BAL中抗炎性IL-10和促炎性IL-6和IL-12的产生。CD40基因敲除(KO)小鼠在CLP后，肺和肝脏中促炎症因子NFkB和抗炎C/EBPB和STAT3转录因子也减少。虽然能够减弱促炎和抗炎信号，但在CD40缺乏的小鼠中，炎症的减弱占主导地位。仅在巨噬细胞和NK细胞(STAT3 KO)条件突变的小鼠肺泡巨噬细胞(AM)表面CD40的表达显著增加，但淋巴细胞在基线水平上表达不明显。根据组织学表现，这些小鼠在亚致死性CLP后有更严重的ALI。这与血清和BAL中IL-6、IL-10和IL-12的产生显著增加有关。相反，STAT3野生型小鼠在CLP诱导的脓毒症后，肺组织学或细胞因子水平没有变化。这些数据增加了AM CD40表达是脓毒症时肺损伤的中枢调节因子的可能性。 我们假设ALI的发生依赖于促炎症转录因子和抗炎转录因子之间的平衡。通过控制这些转录因子的诱导，CD40的AM表达是脓毒症时充分发展ALI所必需的。我们建议在CLP诱导的脓毒症后，检测CD40对巨噬细胞(STAT1和STAT3)中促炎症和抗炎转录因子诱导的调节能力，更好地确定STAT1和STAT3在CD40表达的反馈调节中的作用，并确定CD40阻断剂在脓毒症所致ALI治疗中的作用。

DESCRIPTION (provided by applicant): Acute lung injury (ALI) is a major health problem that is characterized by exudation of fluid into the alveoli and release of proinflammatory cytokines. It is frequently the result of a systemic inflammatory process including sepsis, trauma, hemorrhage and pancreatitis. We have used the cecal ligation and puncture (CLP) model of sepsis to study the importance of the cell surface molecule CD40 in development of ALI in mice. We now report that CLP produces lung capillary leak, interstitial infiltration of inflammatory cells and 30 percent morality at 18 hours. Matched mice with deletion of CD40 have marked attenuation of lung inflammation and 0 percent mortality at 18 hours. CD40 mutation also markedly attenuates production of anti-inflammatory IL-10 and proinflammatory IL-6 and IL-12 in both serum and broncho-alveolar lavage (BAL) after CLP. CD40 knockout (KO) mice also have a reduction of pro-inflammatory NfkB and anti-inflammatory C/EBPB and STAT3 transcription factors after CLP in both the lung and liver. Although capable of attenuating both pro and antiinflammatory signals, attenuation of inflammation predominates in mice deficient in CD40. Mice with a conditional mutation of STAT3 only in macrophages and NK cells (STAT3 KO) have a marked increase in cell surface CD40 expression on alveolar macrophages (AM) but not lymphocytes at baseline. These mice have a more severe ALI after sublethal CLP as evidenced by histologic appearance. This is associated with a marked increase in IL-6, IL-10 and IL-12 production in serum and BAL. Conversely, STAT3 wild type mice had no alterations in either lung histology or cytokine levels after CLP induced sepsis. These data raise the possibility that AM CD40 expression is a central regulator of lung injury during sepsis. We hypothesize that development of ALI depends upon the balance between pro and anti-inflammatory transcription factors. By controlling induction of these transcription factors, AM expression of CD40 is necessary to fully develop ALI during sepsis. We propose to determine the ability of CD40 to modulate pro and anti-inflammatory transcription factor induction in macrophages (STATI and STAT3 respectively) after CLP induced sepsis, better define the role of STAT1 and STAT3 in feedback regulation of CD40 expression and define the utility of CD40 blocking agents for the treatment of sepsis induced ALI.