Macrophage Elastase in Host Defense

巨噬细胞弹性蛋白酶在宿主防御中的作用

• 批准号: 6874953
• 负责人: STEVEN D SHAPIRO
• 金额: $ 36.74万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6874953
• 关键词: alveolar macrophages; angiogenesis inhibitors; angiostatins; antineoplastics; bacterial pneumonia; bactericidal immunity; carcinogenesis inhibitor; collagenase; diphtheria toxin; elastase inhibitor; elastases; genetically modified animals; inflammation; laboratory mouse; lung development; neoplastic growth

DESCRIPTION (provided by applicant): Matrix metalloproteinases (MMPs) are a group of matrix degrading enzymes whose aberrant or excessive expression can lead to a variety of tissue destructive diseases. Less is known about the normal physiologic functions of MMPs. We present data that macrophage elastase (MMP-12) is the only MMP that has direct antimicrobial activity. MMP-12 acts within the lung macrophage as the first line of defense against microbes within the alveolar space. MMPs are well known for their roles in promoting tumor progression. However, with the discovery of angiostatin, an antiangiogenic proteolytic fragment of plasminogen, it became clear that proteinases can be involved in limiting tumor growth. We present evidence that MMP-12 plays a major role in limiting tumor growth within the lung. This property might have clinical importance since at least 6 phase 3 trials using MMP inhibitors for cancer therapy and two for arthritis were stopped last year related to this under-appreciated property of certain MMPs to limit tumor growth. To further define the role of macrophages and MMP-12 in host defense against bacteria and tumors in the lung, we propose to: 1. Test the hypothesis that MMP-12 represents a novel macrophage-mediated intracellular antimicrobial agent. We provide preliminary data that MMP-12-/- mice have a poorer outcome in response to S. aureus pneumonia, MMP-12-/- macrophages have impaired intracellular killing of S. aureus, and show that MMP-12 has direct antimicrobial capacity. This activity is independent of catalytic capacity and involves the non-catalytic C-terminal domain. Studies are proposed to define the spectrum of bacteria influenced by MMP-12. We will also define the structural components of MMP-12 responsible for this activity. 2. We will extend the hypothesis that MMP-12 interferes with tumor growth via inhibition of angiogenesis and further define potential mechanisms of action. We provide preliminary data that MMP-12 is required to maintain dormancy of Lewis lung cell carcinoma (LLC) metastases. This activity appears related to inhibition of angiogenesis. This is not merely due to generation of angiostatin. Additional antiangiogenic protein fragments play a role, and we postulate that MMP-12 also interferes with MMP-2-mediated promotion of tumor growth. MMP-12 might do this by cleavage of MMP-2 as well as by competition with MMP-2 for endothelial cell and tumor cell binding through its C-terminal domain. 3. We will determine the role of macrophages in lung development, bacterial infection, and tumor progression. We will take advantage of MMP-12 macrophage specific expression and complete generation of diphtheria toxin (DT) "knock-in" to the MMP-12 locus. We hypothesize that this will result in mice deficient in lung (and peritoneal) macrophages, and that these mice will undergo normal lung development. If this hypothesis is correct, then the mice will be used to study the requirement of macrophages in host defense and inflammation. If the mutation is lethal or not fully deficient in pulmonary macrophages, then lung-specific transgenic mice will be used to inducibly express DT in lungs of mature mice.

描述（由申请人提供）：基质金属蛋白酶（MMP）是 基质降解酶的组，其异常或过度表达的酶可以 导致多种组织破坏性疾病。对 MMP的正常生理功能。我们提出巨噬细胞弹性酶的数据 （MMP-12）是唯一具有直接抗菌活性的MMP。 MMP-12行为 在肺巨噬细胞中作为对微生物的第一道防线 肺泡空间。 MMP以促进肿瘤的作用而闻名 进展。但是，随着抗血管生成的血管生成素的发现 纤溶酶原的蛋白水解片段，很明显蛋白酶可以是 参与限制肿瘤生长。我们提供了MMP-12的证据 在限制肺部肿瘤生长中的主要作用。这个属性可能有 临床重要性是因为使用MMP抑制剂至少6阶段3期试验 去年，癌症疗法和两种关节炎被停止 某些MMP限制肿瘤生长的特性不足。进一步 定义巨噬细胞和MMP-12在宿主防御细菌和 肺中的肿瘤，我们建议：1。测试MMP-12的假设 代表一种新型的巨噬细胞介导的细胞内抗菌剂。我们 提供MMP-12 - / - 小鼠的初步数据的响应效果较差 对于金黄色葡萄球菌肺炎，MMP-12 - / - 巨噬细胞受损细胞内 杀死金黄色葡萄球菌，并表明MMP-12具有直接的抗菌能力。 该活动与催化能力无关，涉及 非催化C末端结构域。提出了研究来定义 受MMP-12影响的细菌。我们还将定义 MMP-12负责此活动。 2。我们将扩展一个假设 MMP-12通过抑制血管生成干扰肿瘤生长 定义动作的潜在机制。我们提供MMP-12的初步数据 需要维持刘易斯肺细胞癌（LLC）转移的休眠状态。 该活性似乎与抑制血管生成有关。这不仅是 由于血管毒素的产生。附加的抗血管生成蛋白片段 发挥作用，我们假设MMP-12也干扰了MMP-2介导的 促进肿瘤生长。 MMP-12可能会通过MMP-2的裂解和 通过与MMP-2竞争内皮细胞和肿瘤细胞通过 其C末端域。 3。我们将确定巨噬细胞在肺中的作用 发育，细菌感染和肿瘤进展。我们将利用 MMP-12巨噬细胞特异性表达和白喉的完整产生 毒素（DT）“敲入”到MMP-12基因座。我们假设这将导致 在缺乏肺（和腹膜）巨噬细胞的小鼠中，这些小鼠 将经历正常的肺发育。如果这个假设正确，那么 小鼠将用于研究宿主防御中巨噬细胞的需求， 炎。如果突变是致命的或不完全缺乏肺 巨噬细胞，然后将使用肺特异性转基因小鼠诱导 在成熟小鼠的肺中表达DT。