Modeling thoracic aortic aneurysm in zebrafish

斑马鱼胸主动脉瘤建模

• 批准号: 10223412
• 负责人: C. Geoffrey Burns
• 金额: $ 44.25万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10223412
• 关键词: Adoption; Affect; Aneurysm; Animals; Aorta; Aortic Aneurysm; Applications Grants; Automobile Driving; Binding Proteins; Bioinformatics; Blood Vessels; Caliber; Cell Culture Techniques; Cell Proliferation; Cells; Clinical Trials; Connective Tissue Diseases; Cytoskeleton; Data; Data Set; Disease; Dominant-Negative Mutation; Etiology; Gene Expression; Genetic Models; Goals; Heart; Heart Aneurysm; Human; Impairment; Individual; Innovative Therapy; Knowledge; Laboratories; Ligands; Loeys-Dietz Syndrome; Longevity; Mammals; Marfan Syndrome; Medical emergency; Methods; Modality; Modeling; Molecular Chaperones; Molecular Profiling; Morphogenesis; Mus; Mutation; Names; Pathogenesis; Pathway interactions; Patients; Phenotype; Phosphorylation; Plant Roots; Population; Prevention; Production; Proliferating; Publishing; Role; Rupture; Signal Transduction; Smooth Muscle; Smooth Muscle Myocytes; Source; Stress Fibers; Structure; Suggestion; Testing; Thoracic Aortic Aneurysm; Transforming Growth Factor beta; Translating; Uncertainty; Zebrafish; advanced disease; causal variant; design; experimental study; improved; innovation; insight; mouse model; mutant; myocardin; novel; novel lead compound; novel therapeutics; overexpression; premature; prevent; small molecule; tissue stress; transcriptome sequencing

Project Summary Thoracic aortic aneurysms (TAAs), occurring at the aortic root, are cardinal features of Marfan Syndrome (MFS) and Loeys-Dietz Syndrome (LDS) that significantly shorten the lifespans of affected individuals because they dissect and rupture. Causative mutations for MFS and LDS have implicated perturbed TGFβ signaling in TAA pathogenesis. However, considerable uncertainty and controversy abound regarding whether high and/or low TGFβ signaling drives aneurysm formation. Also unclear is whether the nearly universal increases in TGFβ effector phosphorylation (i.e. pSmad2/3 and pErk1/2), observed in advanced disease, are a primary cause or secondary consequence of aortic distention. Lastly, the cellular mechanism by which perturbed TGFβ signaling might promote aneurysm remains undefined. Unfortunately, a small molecule that showed promise in treating aneurysm in MFS mice recently failed in a clinical trial. We have isolated and begun characterizing a novel genetic model of TAA in zebrafish. Animals deficient in Latent-TGFβ binding proteins (Ltbps) 1 and 3 (ltbp1-/-; ltbp3-/-), molecules that sequester TGFβ ligands in the extra cellular matrix (ECM), rapidly develop impressive aneurysm of the cardiac outflow tract (OFT), a structure homologous to the aortic root in mammals, over a two-day period following grossly unperturbed OFT morphogenesis. We present preliminary data documenting several similarities between zebrafish and mammalian aneurysm. The shared features include: 1) greater than 50% increases in aortic diameter; 2) significantly increased phosphorylation of Smad2/3 and Erk1/2 in the aneurysm wall, indicative of high canonical and non-canonical TGFβ signaling, respectively; 3) disorganization of smooth muscle cells which contain prominent stress fibers; 4) a propensity to dissect and/or rupture; and 5) overlapping molecular signatures revealed through a bioinformatics comparison of our recently-acquired RNA-sequencing dataset with a published microarray dataset from MFS mice. Interestingly, we have discovered elevated expression of markers for highly differentiated “contractile” smooth muscle in the OFTs of mutant zebrafish prior to any visible evidence of aneurysm. To my knowledge, few laboratories have investigated gene expression changes in the aortic root prior to aneurysm emergence in mouse models of MFS and LDS. Therefore, this aspect of the phenotype is highly novel. I propose several innovative and hypothesis-driven experimental approaches designed to provide impactful mechanistic insights into TAA pathogenesis. The knowledge obtained will inform ongoing debates over disease mechanisms and bolster efforts to identify novel therapeutic modalities for preventing and treating aneurysmal disease. I propose two Specific Aims: 1) to test the hypothesis that elevated TGFβ signaling is necessary and sufficient to cause aortic aneurysm in zebrafish; and 2) to test the hypothesis that aberrant phenotypic modulation of smooth muscle cells undermines OFT maturation and stability in ltbp1-/-; ltpb3-/- animals.

项目摘要 胸腔主动脉瘤（TAAS）出现在主动脉根部，是Marfan综合征的主要特征 （MFS）和Loeys-Dietz综合征（LDS）大大缩短受影响个人的救生裤，因为 他们剖析和破裂。 MFS和LDS的病因突变已在中扰动TGFβ信号传导 TAA发病机理。但是，关于高和/或 低TGFβ信号传导驱动动脉瘤形成。还不清楚的是TGFβ几乎普遍增加 在晚期疾病中观察到的效应子磷酸化（即PSMAD2/3和PERK1/2）是主要原因或 主动脉扩张的次要后果。最后，扰动TGFβ信号的细胞机制 可能促进动脉瘤仍然不确定。不幸的是，一个在治疗方面表现出希望的小分子 MFS小鼠的动脉瘤最近在一项临床试验中失败。 我们已经孤立并开始表征斑马鱼中TAA的新型遗传模型。动物 缺乏潜在-TGFβ结合蛋白（LTBPS）1和3（LTBP1 - / - ; LTBP3 - / - ），隔离TGFβ的分子 额外的细胞基质（ECM）中的配体，迅速形成了令人印象深刻的心脏出口动脉瘤 （经常），在哺乳动物中与主动脉根同源的结构，在两天的时间内 不受干扰的oft形态发生。我们介绍了初步数据文档 斑马鱼和哺乳动物动脉瘤。共享功能包括：1）主动脉增加50％以上 直径; 2）显着增加了动脉瘤壁中Smad2/3和Erk1/2的磷酸化，表明 高规范和非典型的TGFβ信号传导； 3）平滑肌细胞混乱 包含突出的应力纤维； 4）剖析和/或破裂的承诺； 5）分子重叠 通过我们最近获得的RNA序列数据集的生物信息学比较揭示的签名 带有来自MFS小鼠的发表的微阵列数据集。有趣的是，我们发现 突变斑马鱼的ofts中高度分化的“收缩”平滑肌的标记 可见的动脉瘤证据。据我所知，很少有实验室研究基因表达变化 在MFS和LDS小鼠模型中出现动脉瘤之前的主动脉根。因此，这方面 表型是高度新颖的。我提出了几种创新和假设驱动的实验方法 旨在为TAA发病机理提供有影响力的机械见解。获得的知识将告知 关于疾病机制和鲍尔斯特的持续辩论，以确定新型的热模式 预防和治疗动脉瘤。我提出了两个具体目标：1）检验以下假设。 TGFβ信号升高是必要的，足以在斑马鱼中引起主动脉瘤。 2）测试 假设平滑肌细胞的异常表型调节破坏了成熟和 LTBP1 - / - ; LTPB3 - / - 动物。