Novel Anti-inflammatory Activities For ADAM8 In Pulmonary Emphysema

描述(申请人提供)：慢性阻塞性肺病与高死亡率有关，迫切需要开发新的治疗方法来限制疾病的进展。尽管人们对香烟烟雾(CS，COPD的主要危险因素)如何促进COPD的发展知之甚少，但对可能保护一些吸烟者免受COPD影响的抗炎途径却知之甚少。我们的新数据显示，在暴露于CS的野生型(WT)小鼠肺巨噬细胞中，一种含有去整合素和金属蛋白酶(MP)结构域-8的蛋白酶(Adam8)显著上调。然而，与CS暴露的WT小鼠相比，CS暴露的Adam8-/-小鼠具有更高的肺巨噬细胞计数和更严重的肺气肿伴随的肺巨噬细胞凋亡减少。我们推测，Adam8在CS暴露的小鼠肺中具有抗炎和保护作用，其机制是促进巨噬细胞凋亡，从而减少肺中破坏性巨噬细胞的半衰期。虽然CS上调了小鼠肺巨噬细胞中抗炎的ADAM8水平，但与对照组相比，COPD患者血浆和肺样本中的ADAM8水平降低。我们假设，人类COPD患者血液和血浆中ADAM8水平的降低与人类COPD的疾病严重程度有关，这是通过ADAM8调节人类肺内巨噬细胞的生存来实现的。我们将通过追求以下具体目标来检验这些假说：目标1：我们将使用功能丧失策略(在CS暴露模型中对WT与Adam8-/-小鼠的研究)来检验Adam8通过促进巨噬细胞死亡来保护CS暴露的小鼠肺免受肺气肿的影响的假说。我们将确定涉及的机制。我们还将通过在小鼠肺气肿CS暴露模型中建立和研究Adam8骨髓嵌合小鼠来确定抗炎Adam8在肺中的关键细胞来源。目的：我们将使用功能获得策略来证实Adam8在CS暴露的小鼠肺中具有促进肺巨噬细胞凋亡的抗炎活性。我们将产生在肺巨噬细胞中以诱导方式过表达人类Adam8的转基因小鼠。我们还将使用慢病毒载体，以持久的方式选择性地转导带有hADAM8的小鼠肺巨噬细胞。我们将测试这些策略是否可以预防CS引起的肺气肿和/或限制疾病的进展。目的3：我们将验证我们的假设，即COPD患者ADAM8的表达减少。我们将检测COPD患者和对照组血液和肺样本中ADAM8蛋白和mRNA的水平，并将ADAM8水平与疾病严重程度、肺巨噬细胞计数和肺巨噬细胞凋亡相关联。意义：我们的研究可能对ADAM8介导其在CS暴露的肺组织中的保护作用的机制(S)提供新的见解。我们的研究也可能将ADAM8确定为开发治疗策略的新靶点，以限制COPD患者的肺破坏和疾病进展。

DESCRIPTION (provided by applicant): COPD is associated with high mortality and there is an urgent need to develop new treatments that limit disease progression. Although much is known about how cigarette smoke (CS, the main risk factor for COPD) promotes COPD development, little is known about anti-inflammatory pathways that likely protect some cigarette smokers from developing COPD. Our novel data show that a proteinase with a disintegrin and a metalloproteinase (MP) domain-8 (Adam8) is robustly up-regulated in lung macrophages in wild type (WT) mice exposed to CS. However, CS-exposed Adam8-/- mice have higher lung macrophage counts and worse emphysema associated with decreased lung macrophage apoptosis than CS-exposed WT mice. We hypothesize that Adam8 has anti-inflammatory and protective activities in the CS-exposed murine lung by promoting macrophage apoptosis thereby reducing the half life of destructive macrophages in the lung. Although CS up-regulates anti-inflammatory Adam8 in lung macrophages in mice, ADAM8 levels are reduced in plasma and lung samples from COPD patients when compared to samples from control subjects. We hypothesize that reduced blood and plasma levels of ADAM8 in human COPD patients is linked to disease severity in human COPD via ADAM8 regulating macrophage survival in human lungs. We will test these hypotheses by pursuing the following Specific Aims: Aim 1: We will use a loss-of-function strategy (studies of WT vs. Adam8-/- mice in the CS exposure model) to test the hypothesis that Adam8 protects the CS-exposed murine lung from developing emphysema by promoting macrophage cell death. We will identify the mechanisms involved. We will also determine the critical cellular sources of anti-inflammatory Adam8 in the lung by generating and studying Adam8 bone marrow chimeric mice in the murine CS exposure model of emphysema. Aim 2: We will use gain-of-function strategies to confirm that Adam8 has anti-inflammatory activities in the CS-exposed murine lung by promoting lung macrophage apoptosis. We will generate transgenic mice that overexpress human Adam8 in an inducible fashion in lung macrophages. We will also use lentiviral vectors to selectively transduce murine lung macrophages with hADAM8 in a durable fashion. We will test whether these strategies prevent CS-induced emphysema and/or limit disease progression. Aim 3: We will test our hypothesis that COPD patients have reduced expression of ADAM8. We will measure ADAM8 protein and mRNA levels in blood and lung samples from COPD patients versus control subjects and correlate ADAM8 levels with disease severity, lung macrophage counts, and lung macrophage apoptosis. Significance: Our studies may provide novel insights into the mechanism(s) by which ADAM8 mediates its protective activities in the CS-exposed lung. Our studies may also identify ADAM8 as a novel target for developing therapeutic strategies to limit lung destruction and disease progression in patients with COPD.