Regulation of Cellular Phenotype Change in Thoracic Aortic Aneurysms

胸主动脉瘤细胞表型变化的调节

• 批准号: 10265360
• 负责人: Jeffrey A. Jones
• 金额: --
• 依托单位: RALPH H JOHNSON VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10265360
• 关键词: ACVRL1 gene; Abdominal Aortic Aneurysm; Address; Antibodies; Antibody Therapy; Aortic Rupture; Arteries; Attenuated; Blood; Blood Pressure; C-terminal; CXCL11 gene; Cells; Chest; Complex; DDR2 gene; Data; Deposition; Development; Diabetes Mellitus; Diagnosis; Dilatation - action; Disease; Drug Controls; Endocytosis; Endosomes; Extracellular Matrix; Extracellular Matrix Proteins; Fibroblasts; Foundations; Gelatinase A; Geometry; Growth Factor; Homeostasis; Hypertension; In Vitro; Intervention; Knock-out; Laboratories; Ligands; Link; LoxP-flanked allele; MME gene; Maintenance; Matrix Metalloproteinases; Mediating; Mediator of activation protein; Membrane; Mouse Strains; Mus; Operative Surgical Procedures; Pathway interactions; Patients; Peptides; Performance; Phenotype; Phosphorylation; Play; Process; Production; Recycling; Rest; Risk; Role; Rupture; Series; Signal Transduction; Smoker; Structure; Surface; Symptoms; Tamoxifen; Testing; Therapeutic; Thoracic Aortic Aneurysm; Time; Transforming Growth Factor alpha; Transforming Growth Factor beta; Transforming Growth Factor beta Receptors; Transgenic Mice; Vascular Diseases; Veterans; Work; blood pressure regulation; cell growth regulation; cell type; design; high risk; latent TGF-beta binding protein; macrophage; military veteran; monocyte; mouse model; neutralizing antibody; prevent; programs; repaired; response; surgical risk; transdifferentiation

Thoracic aortic aneurysms (TAAs) develop as a consequence to abnormal remodeling of the aortic extracellular matrix (ECM).10 This usually asymptomatic process results in a weakened aortic wall manifested as gross dilatation that progresses to rupture. Current treatment includes blood pressure management until the risk of rupture outweighs the risk of surgical or endovascular intervention; neither of which address the underlying pathways which drive this devastating disease.11 TAA development is influenced by a series of interrelated mechanisms such as the matrix metalloproteinases (MMPs) 12-15, and dysregulation of the production and deposition of ECM proteins.16 Importantly, these mechanisms are mediated in part through changes in the resident cellular constituents within the aortic wall.17, 18 Transforming growth factor-beta (TGF-β), a soluble peptide growth factor capable of regulating the structure and composition of the aortic ECM, is a well described mediator of fibroblast phenotype.19 Current data shows that the alterations in TGF-β signaling result in a type-I TGF-β receptor switch, from a TGF-β-R1 dominant signal, to an ALK-1 dominant signal. TGF-β is sequestered within the extracellular matrix, bound by latent TGF-β binding proteins (LTBPs).21, 22 These latent complexes are proteolytic targets for key MMPs, such as membrane type-I MMP (MT1-MMP), which is induced during TAA development.8, 23 Results demonstrated that TAA development was attenuated in MT1-MMP heterozygous deficient mice, and neutralizing antibody treatment targeting either TGF-β ligands (TGF-β-NAb) or MT1-MMP activity (MT1-MMP-InhAb) was sufficient to attenuate aortic dilatation; suggesting MT1-MMP as an important mediator of TAA formation and progression. New data demonstrate an increase in the number of mature macrophages (F4/80+) at 8- and 16- weeks post-TAA induction; suggesting that macrophage-derived MT1-MMP may also contribute to TAA development. The present proposal will explore the time-dependent and cell-type specific expression of MT1-MMP using an established and well-characterized mouse model of TAA induction, and several unique transgenic mouse strains. The central hypothesis of this study is that MT1-MMP-dependent activation of TGF-β signaling is both time-dependent and cell-specific, and it will be tested through three specific aims: (1) Demonstrate that fibroblast-derived MT1-MMP is required for TGF-β release and fibroblast transdifferentiation, early in TAA development. Using a validated Tamoxifen-inducible, fibroblast-specific Cre- dependent (Col1A2-Cre-ERT2) knockout of floxed-MT1-MMP, MT1-MMP will be deleted in fibroblasts prior to TAA induction (Early), or after 4-weeks of TAA development (Late); (2) Demonstrate that macrophage-derived MT1-MMP is required for TGF-β release and the maintenance of fibroblast phenotype, late in TAA development. Using a Tamoxifen-inducible, monocyte/macrophage-specific Cre-dependent (LysM-Cre-ERT2) knockout of floxed-MT1-MMP, macrophage-derived MT1-MMP will be knockout. A) prior to TAA induction (Early), or B) after 4-weeks of TAA development (Late); and (3) Demonstrate the efficacy of the MT1-MMP activity-neutralizing antibody as a potential therapeutic for the treatment of TAA disease. Mice will be treated with the antibody prior to TAA induction (Early), or after 4-weeks of TAA development (Late). In each aim, the effects on aortic geometry and structure, the activation of TGF-β signaling (pSmad-1/5/8), fibroblast phenotype/function, and the localization of cell-type specific markers, and MT1-MMP, in the aortic wall will be recorded. Together this set of studies will establish the time-dependent and cell-type-specific expression of MT1-MMP during TAA formation and progression and define its mechanistic role in TAA development.

胸主动脉瘤（TAAs）的发展是由于主动脉细胞外基质的异常重塑， 10这种通常无症状的过程导致主动脉壁变弱，表现为肉眼可见的 扩张发展到破裂。目前的治疗包括血压管理，直到风险 破裂的风险大于外科手术或血管内介入的风险;两者都不能解决潜在的 11 TAA的发展受到一系列相互关联的 如基质金属蛋白酶（MMPs）12-15的机制，以及生产和 16重要的是，这些机制部分是通过改变细胞外基质蛋白质的沉积来介导的。 主动脉壁内的常驻细胞成分。17，18转化生长因子-β（TGF-β），一种可溶性 肽生长因子能够调节主动脉ECM的结构和组成， 目前的数据表明，TGF-β信号转导的改变导致I型胶原蛋白的表达。 TGF-β受体从TGF-β-R1显性信号转换为ALK-1显性信号。TGF-β被隔离 在细胞外基质中，由潜在的TGF-β结合蛋白（LTBP）结合。21，22这些潜在的复合物是 关键MMP的蛋白水解靶点，如在TAA期间诱导的膜I型MMP（MT 1-MMP） 结果表明，MT 1-MMP杂合型患者TAA的发展减弱， 缺陷型小鼠和靶向TGF-β配体（TGF-β-NAb）或MT 1-MMP的中和抗体治疗 活性（MT 1-MMP-InhAb）足以减弱主动脉扩张;提示MT 1-MMP是重要的 TAA形成和进展的介质。新的数据显示，成熟的 巨噬细胞（F4/80+）在TAA诱导后8周和16周;表明巨噬细胞来源的MT 1-MMP 也可能有助于TAA的发展。本提案将探讨时间依赖性和细胞类型 MT 1-MMP的特异性表达使用已建立和充分表征的TAA诱导小鼠模型， 和几种独特的转基因小鼠品系。本研究的中心假设是MT 1-MMP依赖性 TGF-β信号传导的激活是时间依赖性和细胞特异性的，并且将通过三种特异性的方法进行测试。 目的：（1）证明成纤维细胞来源的MT 1-MMP是TGF-β释放和成纤维细胞增殖所必需的。 转分化，在TAA发育的早期。使用经验证的他莫昔芬诱导的成纤维细胞特异性Cre- 依赖性（Col 1A 2-Cre-ERT 2）敲除的MT 1-MMP，MT 1-MMP将在成纤维细胞中缺失， TAA诱导（早期），或TAA发育4周后（晚期）;（2）证明巨噬细胞源性 MT 1-MMP是TAA发展后期TGF-β释放和维持成纤维细胞表型所必需的。 使用他莫昔芬诱导的单核细胞/巨噬细胞特异性Cre依赖性（LysM-Cre-ERT 2）敲除， 敲除巨噬细胞来源的MT 1-MMP。A）TAA诱导前（早期），或B） 4-（3）证明MT 1-MMP活性中和剂的功效 抗体作为治疗TAA疾病的潜在治疗剂。小鼠将先用抗体处理， 至TAA诱导（早期），或TAA发育4周后（晚期）。在每个目标中，对主动脉几何结构的影响 和结构，TGF-β信号转导（pSmad-1/5/8）的激活，成纤维细胞表型/功能，以及 将记录主动脉壁中的细胞类型特异性标志物和MT 1-MMP。这一系列研究将 建立TAA形成过程中MT 1-MMP的时间依赖性和细胞类型特异性表达， 进展，并确定其在TAA发展的机制作用。