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）是主动脉细胞外重塑异常的结果 基质 (ECM).10 这种通常无症状的过程会导致主动脉壁变弱，表现为肉眼可见的 目前的治疗包括血压管理，直至出现破裂的风险。 破裂的风险超过了手术或血管内介入治疗的风险；这两种方法都不能解决根本问题； 驱动这种毁灭性疾病的途径。11 TAA 的发展受到一系列相互关联的影响 基质金属蛋白酶 (MMP) 12-15 等机制，以及生产和代谢失调 ECM 蛋白的沉积。16 重要的是，这些机制部分是通过 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 能够调节主动脉 ECM 的结构和组成的肽生长因子，已被充分描述 成纤维细胞表型的介质。19 目前的数据表明，TGF-β 信号传导的改变会导致 I 型 TGF-β 受体从 TGF-β-R1 主导信号转换为 TGF-β 主导信号。 在细胞外基质内，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 的蛋白水解靶标，例如 TAA 期间诱导的膜 I 型 MMP (MT1-MMP) 8, 23 结果表明，MT1-MMP 杂合子中 TAA 发育减弱 缺陷小鼠，以及针对 TGF-β 配体 (TGF-β-NAb) 或 MT1-MMP 的中和抗体治疗 活性 (MT1-MMP-InhAb) 足以减弱主动脉扩张；表明 MT1-MMP 是一种重要的作用； 新数据表明成熟细胞数量有所增加。 TAA 诱导后 8 周和 16 周的巨噬细胞 (F4/80+) 表明巨噬细胞衍生的 MT1-MMP 也可能有助于 TAA 的发展。目前的提案将探讨时间依赖性和细胞类型。 使用已建立且特征良好的 TAA 诱导小鼠模型进行 MT1-MMP 的特异性表达， 以及几种独特的转基因小鼠品系 本研究的中心假设是 MT1-MMP 依赖性。 TGF-β信号传导的激活既具有时间依赖性又具有细胞特异性，将通过三个特定的测试 目的：(1) 证明成纤维细胞衍生的 MT1-MMP 是 TGF-β 释放和成纤维细胞所必需的 使用经过验证的他莫昔芬诱导的成纤维细胞特异性 Cre- 进行转分化。 floxed-MT1-MMP 依赖性 (Col1A2-Cre-ERT2) 敲除，MT1-MMP 将在成纤维细胞中被删除 TAA 诱导（早期），或 TAA 发育 4 周后（晚期）；(2) 证明巨噬细胞来源 在 TAA 发育后期，MT1-MMP 是 TGF-β 释放和成纤维细胞表型维持所必需的。 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-ERT2) 敲除 floxed-MT1-MMP、巨噬细胞衍生的 MT1-MMP 将在 A) TAA 诱导之前（早期）或 B) 之后被敲除。 4 周的 TAA 开发（后期）；以及 (3) 证明 MT1-MMP 活性中和的功效 抗体作为治疗 TAA 疾病的潜在疗法，将先用该抗体治疗小鼠。 TAA 诱导（早期），或 TAA 发展 4 周后（晚期）在每个目标中，对主动脉几何形状的影响。 和结构、TGF-β信号传导 (pSmad-1/5/8) 的激活、成纤维细胞表型/功能和定位 这组研究将一起记录主动脉壁中的细胞类型特异性标记物和 MT1-MMP。 建立 TAA 形成过程中 MT1-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 发展中的机制作用。