Physiological role of MT1-MMP-mediated, proteolysis-independent signaling in vivo

MT1-MMP 介导的、不依赖于蛋白水解的体内信号传导的生理作用

• 批准号: 8264303
• 负责人: Paolo Mignatti
• 金额: $ 3.38万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2012-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8264303
• 关键词: Adult; Advocate; Affect; Age; Alveolar; Apoptosis; Blood Vessels; Cartilage; Cell Proliferation; Chondrocytes; Cytoplasmic Tail; Deceleration; Defect; Development; Epiphysial cartilage; Genetic; Genetic Models; Growth; Health; Hemopexin; In Vitro; Knockout Mice; Knowledge; Lung; MMP14 gene; Matrix Metalloproteinases; Mediating; Minor; Mouse Strains; Mus; Mutant Strains Mice; Mutation; Pathologic Processes; Pathology; Peptide Hydrolases; Phenotype; Physiological; Physiological Processes; Physiology; Proteolysis; Publishing; Role; Signal Transduction; Skeletal Development; Transgenic Mice; Vascularization; angiogenesis; cell motility; extracellular; human MMP14 protein; in vivo; insight; long bone; mutant; novel; postnatal; skeletal

DESCRIPTION (provided by applicant): Membrane-type 1 matrix metalloproteinase (MT1-MMP), a transmembrane proteinase with extracellular catalytic, hemopexin-like (PEX) and hinge domains, and a short cytoplasmic tail, has been implicated in a variety of physiological and pathological processes. Unlike the other MMPs, whose genetic deficiency has minor phenotypic effects, the genetic deficiency of MT1-MMP causes severe defects in skeletal development with marked deceleration of postnatal growth, shortening of long bones, defective vascularization of the cartilage and delayed formation of secondary ossification centers. In addition, MT1- MMP-deficient mice show important defects in alveolar development and adult angiogenesis, and die by 3 weeks of age. It has been proposed that the phenotype of these mice results from the lack of the proteolytic activity of MT1-MMP. Our recently published, extensive studies have shown that MT1-MMP mediates the activation of intracellular signaling by a proteolysis-independent mechanism that stimulates cell proliferation and migration in vitro and in vivo. MT1-MMP activation of intracellular signaling is mediated by a specific sequence of the cytoplasmic tail and independent of the MT1-MMP proteolytic activity. While this novel and unexpected finding does not diminish the well-established importance of the proteolytic activity of MT1-MMP, it strongly advocates a very important role for the signaling mechanism we identified, and indicates that the phenotype of MT1-MMP null mice can result at least in part from lack of MT1-MMP-mediated signaling. The signaling mechanism we discovered is a novel, proteolysis-independent activity of MT1-MMP that may have important roles in chondrocyte proliferation in the growth plates, formation of secondary ossification centers, skeletal and alveolar development, and in adult angiogenesis. Therefore, we propose to study the physiological role of MT1-MMP- mediated intracellular signaling by developing the following Specific Aim: To generate and characterize the phenotype of a transgenic mouse with a subtle mutation that abolishes MT1-MMP-mediated intracellular signaling. We propose to generate a strain of mice expressing a mutation in the MT1-MMP cytoplasmic tail that abolishes the signaling capacity without affecting the proteolytic activity of MT1-MMP, and to compare their phenotype to those of wt and MT1-MMP null mice. We expect that expression of this mutant MT1-MMP will result in a phenotype that partially recapitulates the phenotype of MT1-MMP null mice. Therefore, the analysis of the phenotype of our mutant mice will allow us to understand the role of MT1-MMP-mediated signaling in development, normal physiology and pathology. PUBLIC HEALTH RELEVANCE: We found an unexpected, paradigm-shifting mechanism that controls cell proliferation and migration in vitro and in vivo. Therefore, we propose to generate and characterize a genetic model in mice to understand the role of this novel mechanism in development, normal physiology and in pathology. The knowledge derived from our study can provide important insight into skeletal and pulmonary alveolar development and in blood vessel formation (angiogenesis).

描述（由申请人提供）：膜类型1基质金属蛋白酶（MT1-MMP），一种具有细胞外催化，血兴蛋白（PEX）和铰链结构型的跨膜蛋白酶，以及短的细胞质尾巴，已涉及各种生理学和病理学过程。与其他MMP不同，其遗传缺乏具有较小的表型作用，MT1-MMP的遗传缺乏会在骨骼发育中引起严重的缺陷，其产后生长的明显减速，长骨骼的缩短，软骨的缺陷血管缩短，软骨的缺陷和次级骨化中心的延迟形成。此外，MT1-缺陷小鼠在肺泡发育和成人血管生成中显示出重要的缺陷，并在3周龄时死亡。已经提出，这些小鼠的表型是由于缺乏MT1-MMP的蛋白水解活性而导致的。我们最近发表的广泛研究表明，MT1-MMP通过蛋白水解独立的机制介导细胞内信号传导的激活，该机制刺激细胞增殖和体外和体内迁移。细胞内信号传导的MT1-MMP激活是由细胞质尾部的特定序列介导的，并且与MT1-MMP蛋白水解活性无关。尽管这一新颖而出乎意料的发现并没有减少MT1-MMP蛋白水解活性的良好重要性，但它强烈提倡我们确定的信号传导机制的一个非常重要的作用，并表明MT1-MMP NULL小鼠的表型至少可以归因于缺乏MT1-MMP介导的信号介导的部分。我们发现的信号传导机制是MT1-MMP的一种新颖的，蛋白水解的非依赖性活性，在生长板中可能具有重要作用，在生长板中具有重要作用，次级骨化中心的形成，骨骼和肺泡发育以及成人血管生成。因此，我们建议通过开发以下特定目的来研究MT1-MMP介导的细胞内信号传导的生理作用：生成和表征转基因小鼠的表型，其微妙的突变消除了MT1-MMP介导的细胞内信号传导。我们建议在MT1-MMP细胞质尾部中产生一种表达突变的小鼠，该尾巴废除了信号传导能力，而不会影响MT1-MMP的蛋白水解活性，并将其表型与WT和MT1-MMP NULL小鼠的表型进行比较。我们期望这种突变体MT1-MMP的表达会导致表型部分概括MT1-MMP无效小鼠的表型。因此，对突变小鼠表型的分析将使我们能够了解MT1-MMP介导的信号在发育，正常生理和病理学中的作用。公共卫生相关性：我们发现了一种意外的范式转移机制，可以控制细胞的增殖和体外迁移。因此，我们建议在小鼠中产生和表征遗传模型，以了解这种新型机制在发育，正常生理和病理学中的作用。从我们的研究中得出的知识可以为骨骼和肺肺泡发育以及血管形成（血管生成）提供重要的见解。