The Effects of KLF4 in experimental aortic aneurysm formation

KLF4 对实验性主动脉瘤形成的影响

• 批准号: 8024545
• 负责人: Gorav Ailawadi
• 金额: $ 13.12万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-10 至 2014-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8024545
• 关键词: Accounting; Actins; Aneurysm; Aorta; Aortic Aneurysm; Apoptosis; Atherosclerosis; Binding; Binding Sites; Biological Assay; Birth; Blood Vessels; Bone Marrow; Bone Marrow Cells; Bone Marrow Transplantation; CCL2 gene; Caliber; Cause of Death; Cell Proliferation; Cells; Collagen; Consensus; Data; Disease; Disease Progression; Down-Regulation; Elastases; Elastin; Elements; Embryo; Endothelial Cells; Enzymes; Epigenetic Process; Exhibits; Extracellular Matrix; GKLF protein; Gene Activation; Gene Expression; Genes; Growth; Health; Histone H4; Histones; Human; Immunohistochemistry; In Vitro; Infiltration; Inflammatory; Injury; Knock-out; Knockout Mice; Laboratories; Lesion; Leukocytes; Ligation; MMP3 gene; Maintenance; Manuscripts; Marrow; Matrix Metalloproteinases; Medial; Mediating; Medical; Mentors; Mesenchymal; Methods; Methylation; Modeling; Modification; Molecular; Mus; Mutation; Nucleic Acid Regulatory Sequences; Operative Surgical Procedures; Pathogenesis; Pattern; Perfusion; Phenotype; Phospholipids; Play; Preparation; Principal Investigator; Production; Promoter Regions; Proteins; Regulation; Relative (related person); Repression; Resolution; Role; SWI1; Serum Response Factor; Smooth Muscle Myocytes; Somatic Cell; T-Lymphocyte; Tamoxifen; Testing; Thick; Tissues; Transcriptional Activation; Transgenic Organisms; Up-Regulation; Vascular Cell Adhesion Molecule-1; Wild Type Mouse; cell determination; cell type; chromatin immunoprecipitation; cytokine; embryonic stem cell; histone modification; in vivo; interest; macrophage; neointima formation; novel; pluripotency; prevent; programs; promoter; receptor; reconstitution; repaired; response; stem; therapeutic target; transcription factor

DESCRIPTION (provided by applicant): Ailawadi, Gorav Project Summary Aortic aneurysms (AA) are the 13th leading cause of death in the U.S. Since no medical therapy exists to alter the progression of disease, understanding the pathogenesis of AA is an important undertaking. The hallmark of AAs includes inflammatory infiltration, matrix metalloproteinase (MMP) production by macrophages and smooth muscle cells (SMCs) leading to destruction of collagen and elastin in the aortic wall and vessel dilation. Our preliminary data suggests that SMCs undergo phenotypic switching defined by increased SMC production of MMPs and downregulation of SMC contractile marker genes prior to experimental aneurysm formation. The loss of Kruppel like factor-4 (KLF4) has been shown to delay phenotypic switching to an inflammatory phenotype in a ligation-induced model of vascular injury. Moreover, in this model, KLF4 loss resulted in hyperproliferation of medial SMCs. KLF4 appears to have opposing effects in macrophages and endothelial cells. Preliminary studies in our lab have documented KLF4 is profoundly elevated in human and experimental aneurysms by immunohistochemistry. The focus of this proposal is to test the hypothesis that KLF4 plays a key role in experimental aneurysms and that effects are mediated through actions of KLF4 in SMCs, macrophages, and/ or endothelial cells. Aim 1 will determine if conditional KLF4 knockout mice show altered formation of aneurysms and if effects are mediated through effects in SMCs or in other cell types. We will utilize several unique transgenic knockout mice developed in the Owens (mentor's) lab as well as bone marrow reconstitution studies that will allow cell specific deletion of KLF4 and subject them to an experimental aneurysm formation using elastase perfusion. Aim 2 will determine if epigenetic mechanisms contribute to the effects of KLF4 on aortic aneurysm formation. Studies will test the hypothesis that KLF4 contributes to suppression of SMC marker genes and activation of several inflammatory genes within aneurysms, by binding to promoters in each of these genes, mediating histone modifications association with transcriptional silencing and activation. Finally, we will determine if these epigenetic modifications in AA are KLF4 dependent using KLF4 knockout mice. PHS 398/2590 (Rev. 11/07) Page Continuation Format Page PUBLIC HEALTH RELEVANCE: Program Director/Principal Investigator (Last, First, Middle): Ailawadi, Gorav Project Narrative/ Relevance There are no proven medical treatments to alter progression of aneurysm disease. KLF4 delays SMC phenotypic switching to an inflammatory state in models of vascular injury. Furthermore, KLF4 is highly upregulated in AA. Loss of KLF4 studies will allow us to determine the effect of KLF4 and SMC phenotype in the progression of disease and determine if this is a potential therapeutic target to slow AA progression.

描述（由申请人提供）：Ailawadi，Gorav 项目摘要 主动脉瘤 (AA) 是美国第 13 大死亡原因。由于没有药物疗法可以改变疾病的进展，因此了解 AA 的发病机制是一项重要的任务。 AA 的特点包括炎症浸润、巨噬细胞和平滑肌细胞 (SMC) 产生基质金属蛋白酶 (MMP)，导致主动脉壁胶原蛋白和弹性蛋白破坏以及血管扩张。我们的初步数据表明，在实验性动脉瘤形成之前，SMC 经历了表型转换，其定义为 SMC 的 MMP 产量增加和 SMC 收缩标记基因的下调。在结扎诱导的血管损伤模型中，Kruppel 样因子 4 (KLF4) 的缺失已被证明可以延迟表型向炎症表型的转变。此外，在该模型中，KLF4 缺失导致内侧 SMC 过度增殖。 KLF4 似乎在巨噬细胞和内皮细胞中具有相反的作用。我们实验室的初步研究表明，免疫组织化学显示 KLF4 在人类和实验性动脉瘤中显着升高。该提案的重点是检验以下假设：KLF4 在实验性动脉瘤中发挥关键作用，并且作用是通过 KLF4 在 SMC、巨噬细胞和/或内皮细胞中的作用介导的。目标 1 将确定条件性 KLF4 敲除小鼠是否表现出动脉瘤形成的改变，以及效应是否是通过 SMC 或其他细胞类型的效应介导的。我们将利用 Owens（导师）实验室开发的几种独特的转基因敲除小鼠以及骨髓重建研究，这些研究将允许细胞特异性删除 KLF4，并使用弹性蛋白酶灌注对它们进行实验性动脉瘤形成。目标 2 将确定表观遗传机制是否有助于 KLF4 对主动脉瘤形成的影响。研究将测试这样的假设：KLF4 通过与每个基因的启动子结合，介导与转录沉默和激活相关的组蛋白修饰，从而有助于抑制 SMC 标记基因和激活动脉瘤内的多个炎症基因。最后，我们将使用 KLF4 敲除小鼠确定 AA 中的这些表观遗传修饰是否依赖于 KLF4。 PHS 398/2590（修订版 11/07） 页面延续 格式页面 公共卫生相关性： 项目总监/首席研究员（最后、第一、中）：Ailawadi、Gorav 项目叙述/相关性 目前还没有经过证实的医学治疗方法可以改变动脉瘤疾病的进展。在血管损伤模型中，KLF4 延迟 SMC 表型向炎症状态的转变。此外，KLF4 在 AA 中高度上调。 KLF4 研究的失败将使我们能够确定 KLF4 和 SMC 表型在疾病进展中的影响，并确定这是否是减缓 AA 进展的潜在治疗靶点。