EMAP II, a molecular link of inflammation and apoptosis in pulmonary emphysema.

描述（由申请人提供）：香烟烟雾通过导致肺基质和细胞成分损失的机制诱导肺气肿。解释肺气肿的两个主要范例假定a）由炎症触发的蛋白酶/抗蛋白酶失衡和B）导致毛细血管退化的过度肺泡内皮细胞凋亡的状态。这两种机制可以解释肺泡壁的丧失是肺气肿的特征。然而，肺气肿中过度的肺结构细胞凋亡与活化的炎症状态的共存及其相互作用的层次尚未得到解释。我们提出，过量的内皮单核细胞激活蛋白（EMAP II）是一个统一的分子机制，连接细胞凋亡和炎症在肺气肿。EMAP II是由肺气肿肺中存在的病症诱导的细胞因子，在被已知参与COPD的半胱天冬酶和基质金属蛋白酶蛋白水解裂解后从细胞释放。我们确定CXCR3作为EMAP II的功能性受体，其介导EMAP II诱导的内皮细胞凋亡和单核细胞活化。考虑到EMAP II对内皮细胞的强效促凋亡作用，以及其激活和募集促炎单核细胞的能力，我们假设吸烟引起的过量EMAP II释放涉及肺内皮细胞凋亡和单核细胞炎症激活，因此是肺气肿的关键分子介质。我们推测烟雾诱导EMAP II，EMAP II导致CXCR3依赖性内皮细胞凋亡并激活单核细胞。活化的半胱天冬酶和基质金属蛋白酶可能进一步增加肺中的EMAP II，放大最终导致肺气肿的损伤信号。这些研究与人类肺气肿有关，因为我们测量了肺气肿患者肺中EMAP II的增加。事实上，我们的数据表明，烟雾诱导的肺气肿之前，EMAP II的生产和细胞凋亡的小鼠和肺特异性EMAP II的增加足以导致肺细胞凋亡和肺气肿。我们将测试的功能分泌EMAP II及其受体的中和抗体在香烟烟雾诱导的肺气肿小鼠和条件EMAP II转基因过表达在肺。我们制定了三个具体目标：1。确定EMAP II是否是香烟烟雾诱导的肺气肿的生物标志物和分子介质。2研究是否过量的肺EMAP II通过触发肺内皮细胞凋亡或通过募集单核细胞/巨噬细胞诱导肺气肿，以及3.探讨EMAP Ⅱ诱导人肺内皮细胞凋亡的机制。如果实现这些目标，预期将EMAP II定位为肺气肿的治疗靶点和/或生物标志物。项目叙述：我们建议，我们的实验计划将使我们能够确定一个关键的球员在肺气肿; EMAP II，这可能成为一个生物标志物可测量的生物液体，也可能被证明是一个有吸引力的药理学目标的疾病与稀缺的治疗选择，和高发病率和死亡率。由细胞应激刺激的过度EMAP II释放和持续的蛋白酶活化将导致肺中肺泡破坏的恶性和值得靶向的循环。此外，我们的工作将允许细化内皮细胞凋亡的机制，同时统一该领域的两个理论，即过度炎症与过度凋亡。

DESCRIPTION (provided by applicant): Cigarette smoke induces emphysema through mechanisms which cause a loss of both matrix and cellular elements of the lung. The two main paradigms to explain emphysema postulate a) an imbalance of protease/antiproteases triggered by inflammation and b) a state of excessive alveolar endothelial apoptosis causing capillary regression. These two mechanisms would explain the loss of alveolar wall characterizing emphysema. However, the coexistence of an excessive lung structural cell apoptosis with that of an activated inflammatory state in emphysema and the hierarchy of their interaction have not yet been explained. We propose the excess of endothelial-monocyte-activating protein (EMAP II) is a unifying molecular mechanism to link apoptosis and inflammation in emphysema. EMAP II is a cytokine induced by conditions present in emphysematous lungs, being released from cells upon proteolytic cleavage by caspases and matrix metalloproteinases, which are known to participate in COPD. We identified CXCR3 as a functional receptor for EMAP II which mediates EMAP II-induced endothelial cell apoptosis and monocyte activation. Given the potent pro-apoptotic effect of EMAP II on endothelial cells, coupled with its ability to activate and recruit pro-inflammatory monocytes, we hypothesize that excessive EMAP II release in response to cigarette smoking engages both lung endothelial cell apoptosis and monocyte inflammatory activation, and therefore is a key molecular mediator of emphysema. We postulate that smoke induces EMAP II, which causes CXCR3- dependent endothelial apoptosis and activates monocytes. Activated caspases and matrix metalloproteinases may further increase EMAP II in the lung, amplifying damage signals that culminate in emphysema. These studies are relevant to human emphysema, as we measured increased EMAP II in the lungs of emphysema patients. Indeed, our data indicate that smoke-induced emphysema is preceded by EMAP II production and apoptosis in mice and lung-specific EMAP II increases are sufficient to cause lung apoptosis and emphysema. We will test the function of the secreted EMAP II and its receptor by neutralizing antibodies in cigarette smoke-induced emphysema in mice and conditional EMAP II transgenic overexpression in the lung. We developed 3 specific aims: 1. To determine whether EMAP II is a biomarker and molecular mediator of cigarette smoke-induced emphysema. 2 To investigate whether excessive lung EMAP II induces emphysema by triggering lung endothelial cell apoptosis or by recruitment of monocytes/macrophages, and 3. To determine the mechanism of EMAP II-induced cell apoptosis in primary human endothelial lung cells. These aims, if achieved are expected to position EMAP II as a therapeutic target and/or biomarker of emphysema. PROJECT NARRATIVE: We propose that our experimental plan will allow us to identify a key player in emphysema; EMAP II, which may become a biomarker measurable in biological fluids, and may also prove to be an attractive pharmacological target in a disease with scarce therapeutical options, and a high morbidity and mortality. The excessive EMAP II release stimulated by cellular stresses and ongoing protease activation would account for a vicious and worth targeting cycle of alveolar destruction in the lung. Furthermore, our work will allow to refine mechanisms of endothelial cell apoptosis while unifying the two theories in the field, that of excessive inflammation with that of excessive apoptosis.