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: 6479543
• 负责人: STEVEN D SHAPIRO
• 金额: $ 36.64万
• 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/6479543
• 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）是一种 一组基质降解酶，其异常或过度表达可以 导致多种组织破坏性疾病。对此知之甚少 MMP 的正常生理功能。我们提供的数据表明巨噬细胞弹性蛋白酶 (MMP-12) 是唯一具有直接抗菌活性的 MMP。 MMP-12作用 肺巨噬细胞是抵抗肺内微生物的第一道防线 肺泡空间。 MMP 因其促进肿瘤生长的作用而闻名 进展。然而，随着血管抑制素（一种抗血管生成药物）的发现 纤溶酶原的蛋白水解片段，很明显蛋白酶可以 参与限制肿瘤生长。我们提供的证据表明 MMP-12 发挥着 在限制肺内肿瘤生长方面发挥着重要作用。该属性可能有 至少 6 项使用 MMP 抑制剂进行 3 期试验以来具有临床重要性 去年，与此相关的癌症治疗和两种关节炎治疗被停止 某些 MMP 限制肿瘤生长的特性未被充分认识。为了进一步 定义巨噬细胞和 MMP-12 在宿主防御细菌中的作用 对于肺部肿瘤，我们建议： 1. 检验 MMP-12 的假设 代表一种新型巨噬细胞介导的细胞内抗菌剂。我们 提供初步数据表明 MMP-12-/- 小鼠的反应结果较差 对于金黄色葡萄球菌肺炎，MMP-12-/-巨噬细胞的细胞内功能受损 杀灭金黄色葡萄球菌，并表明MMP-12具有直接抗菌能力。 该活性与催化能力无关，并且涉及 非催化C端结构域。建议进行研究来定义范围 受 MMP-12 影响的细菌。我们还将定义结构组件 MMP-12负责这项活动。 2. 我们将扩展假设 MMP-12 通过抑制血管生成来干扰肿瘤生长，并进一步 定义潜在的作用机制。我们提供的初步数据表明MMP-12 维持 Lewis 肺细胞癌 (LLC) 转移的休眠是必需的。 该活性似乎与血管生成的抑制有关。这不仅仅是 由于血管抑制素的产生。额外的抗血管生成蛋白片段 发挥作用，我们假设 MMP-12 也会干扰 MMP-2 介导的 促进肿瘤生长。 MMP-12 可能通过切割 MMP-2 以及 通过与 MMP-2 竞争内皮细胞和肿瘤细胞的结合 它的 C 末端结构域。 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”MMP-12 位点。我们假设这会导致 在肺（和腹膜）巨噬细胞缺陷的小鼠中，这些小鼠 将进行正常的肺部发育。如果这个假设是正确的，那么 小鼠将被用于研究巨噬细胞在宿主防御中的需求 炎。如果突变是致命的或肺功能未完全缺乏 巨噬细胞，然后肺特异性转基因小鼠将被用于诱导 在成熟小鼠的肺部表达DT。