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: 7769518
• 负责人: Paolo Mignatti
• 金额: $ 20.64万
• 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/7769518
• 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; Hemopexin; In Vitro; Knockout Mice; Knowledge; Lung; Matrix Metalloproteinases; Mediating; Minor; Mouse Strains; Mus; Mutant Strains Mice; Mutation; Pathologic Processes; Pathology; Peptide Hydrolases; Phenotype; Physiological; Physiology; Proteolysis; Publishing; Role; Signal Transduction; Skeletal Development; Transgenic Mice; Vascularization; angiogenesis; extracellular; human MMP14 protein; in vivo; insight; long bone; migration; mutant; novel; postnatal; public health relevance; 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1型基质金属蛋白酶（MT 1-MMP）是一种具有细胞外催化、血红素样（PEX）和铰链结构域以及短胞质尾区的跨膜蛋白酶，与多种生理和病理过程有关。与其他MMPs不同，其遗传缺陷具有较小的表型效应，MT 1-MMP的遗传缺陷导致骨骼发育的严重缺陷，具有出生后生长显著减速、长骨缩短、软骨血管化缺陷和次级骨化中心形成延迟。此外，MT 1-MMP缺陷小鼠在肺泡发育和成体血管生成方面表现出重要的缺陷，并在3周龄时死亡。已经提出这些小鼠的表型是由于缺乏MT 1-MMP的蛋白水解活性。我们最近发表的广泛研究表明，MT 1-MMP介导激活的细胞内信号的蛋白水解独立的机制，刺激细胞增殖和迁移在体外和体内。MT 1-MMP激活胞内信号传导是由胞质尾区的特定序列介导的，并且不依赖于MT 1-MMP蛋白水解活性。虽然这一新的和意想不到的发现并没有削弱MT 1-MMP的蛋白水解活性的公认的重要性，但它强烈主张我们鉴定的信号传导机制的非常重要的作用，并表明MT 1-MMP缺失小鼠的表型至少部分是由于缺乏MT 1-MMP介导的信号传导。我们发现的信号传导机制是一种新的，不依赖于蛋白水解的MT 1-MMP活性，可能在生长板中的软骨细胞增殖，次级骨化中心的形成，骨骼和肺泡发育以及成人血管生成中发挥重要作用。因此，我们建议通过开发以下具体目标来研究MT 1-MMP介导的细胞内信号传导的生理作用：产生并表征具有消除MT 1-MMP介导的细胞内信号传导的微小突变的转基因小鼠的表型。我们建议产生一种在MT 1-MMP胞质尾部表达突变的小鼠品系，该突变废除了信号传导能力而不影响MT 1-MMP的蛋白水解活性，并将其表型与野生型和MT 1-MMP缺失小鼠的表型进行比较。我们预期这种突变MT 1-MMP的表达将导致部分重现MT 1-MMP缺失小鼠表型的表型。因此，我们的突变小鼠的表型的分析将使我们能够了解MT 1-MMP介导的信号在发育，正常生理和病理中的作用。公共卫生相关性：我们发现了一种意想不到的范式转变机制，可以在体外和体内控制细胞增殖和迁移。因此，我们建议在小鼠中生成和表征遗传模型，以了解这种新机制在发育，正常生理和病理中的作用。从我们的研究中获得的知识可以为骨骼和肺泡发育以及血管形成（血管生成）提供重要的见解。