Role of Vascular Smooth Muscle Bcl11b in Arterial Stiffness

血管平滑肌 Bcl11b 在动脉僵硬中的作用

基本信息

批准号：
10339393
负责人：
Francesca Seta
金额：
$ 41.25万
依托单位：
BOSTON UNIVERSITY MEDICAL CAMPUS
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-04-01 至 2024-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10339393
关键词：
Acetylation Actins Adult Aging Agonist American Angiotensin II Aorta Aortic Aneurysm Arteries B-Cell Leukemia BCL1 Oncogene Binding Binding Sites Biochemical Biological Assay Blood Vessels Cardiovascular Diseases ChIP-seq Chromatin Chromosome 14 Co-Immunoprecipitations Collagen Complex Contractile Proteins DNA Binding Deacetylase Dependovirus Development Diet Elastin Embryonic Development Enhancers Epigenetic Process Extracellular Matrix Fatty acid glycerol esters Focal Adhesions Functional disorder G Actin Gene Expression Genes Genetic Genetic Transcription Goals Gold Heart Atrium Histone Deacetylase Histone H3 Human Impairment In Situ Incidence Junk DNA Knock-out Lead Ligation MYH11 gene Maintenance Measures Mechanics Modeling Molecular Mus Muscle Contraction Muscle Tonus Muscle function Myosin ATPase Neurons Obesity Pathogenesis Phenotype Physiologic pulse Play Process Proteins Risk Risk Factors Role SIRT1 gene Signal Transduction Single Nucleotide Polymorphism Smooth Muscle Smooth Muscle Actin Staining Method Smooth Muscle Myocytes Smooth Muscle Myosins Structure Sucrose System T-Lymphocyte Testing Therapeutic Transgenic Mice Variant Vascular Smooth Muscle Wild Type Mouse adeno-associated viral vector aged alpha Actin arterial stiffness biomechanical test cardiovascular disorder risk cardiovascular risk factor design genome wide association study genomic locus in vivo indexing innovation mechanical properties mouse model muscle stiffness novel novel therapeutic intervention overexpression polymerization prevent promoter protein expression recruit standard measure therapeutic evaluation transcription factor translational approach translational potential vascular contributions vasculogenesis

项目摘要

Arterial stiffening (AS), the progressive loss of compliance in elastic arteries, increases the risk of developing cardiovascular diseases (CVDs). However, cellular and molecular mechanisms of AS are poorly understood. Determining these mechanisms may lead to innovative strategies that can slow or reverse AS and thus decrease the risk of developing CVD. A gene desert locus on chromosome 14, downstream of the gene Bcl11b, has recently been shown to harbor single nucleotide polymorphisms (SNPs) with a highly significant association with AS. We were the first to show knocking out Bcl11b in mice (BSMKO), both globally and specifically in vascular smooth muscle (VSM), caused elevated AS, and increased the incidence of angiotensin II-induced aortic aneurysms. In addition, we showed Bcl11b expression is downregulated in aortas of two models of AS (mice fed high fat, high sucrose (HFHS) diet and aged mice), and Bcl11b transcriptionally regulates contractile protein expression, including smooth muscle myosin (MYH11) and smooth muscle α-actin (α-SMA). Taken together, we hypothesize that SNP variants in the 3'-Bcl11b gene desert region regulate and suppress Bcl11b expression, playing a causative role in the pathogenesis of AS. We hypothesize that stiff aortas have decreased Bcl11b expression, stimulating alterations in VSM contractile phenotype and/or extracellular matrix (ECM) remodeling, or a combination of these factors, thereby impairing structural and functional integrity of the aorta. In Aim 1, we will use biaxial mechanical testing on wild type and BSMKO aortas together with a microstructurally-motivated constitutive model to dissect the contribution of smooth muscle cells, elastin and collagen to aortic wall stiffness, at baseline and after contractile agonist stimulation. We will then correlate the results of biaxial tests to molecular expressions of VSM contractile, actin polymerization, and focal adhesion proteins known to contribute to VSM tone and stiffness. In Aim 2, we will use chromatin immunoprecipitation (ChIP)-sequencing on VSM homogenates to identify Bcl11b VSM-specific DNA binding sites. We will also test the hypothesis that Bcl11b epigenetically regulates MYH11 and α-SMA gene expression by recruiting the histone deacetylase sirtuin-1 at G/C motifs in their gene promoters. In Aim 3, we will overexpress Bcl11b using transgenic mice or, for a more translational approach, by administering a AAV2/5 vector, to determine if increasing Bcl11b rescues impaired VSM-specific molecular mechanisms of VSM contraction and/or VSM cell-extracellular matrix interaction (e.g., contractile proteins, focal adhesion complexes, actin polymerization) in obese and aged mice. Definitive decreases in VSM stiffness and pulse wave velocity, the in vivo index of AS, would establish that targeting Bcl11b is a viable strategy for ameliorating AS and thus preventing CVD.

动脉僵硬（AS），弹性动脉的依从性逐渐丧失，增加了发展心血管疾病（CVD）。但是，AS的细胞和分子机制理解不佳。确定这些机制可能会导致创新的策略，这些策略可能会放慢或反向AS，从而降低了发展CVD的风险。 14染色体上的基因沙漠基因座，基因BCl11b的下游最近已显示出具有单个核苷酸多态性（SNP）与AS具有非常重要的关联。我们是第一个展示敲除bcl11b的人小鼠（BSMKO），全球和特别是血管平滑肌（VSM），导致AS升高并增加了血管紧张素II诱导的主动脉瘤的发生率。此外，我们显示了Bcl11b 表达在两种AS的主动脉中被下调（小鼠喂养高脂肪，高蔗糖（HFHS）饮食和老年小鼠），Bcl11b转录调节收缩蛋白表达，包括平滑肌肉肌球蛋白（MYH11）和平滑肌α-肌动蛋白（α-SMA）。综上所述，我们假设 3'-BCl11b基因沙漠地区的SNP变体调节并抑制BCL11b表达，玩在AS的发病机理中的致病作用。我们假设僵硬的主动脉降低了Bcl11b的表达，刺激了VSM的改变收缩表型和/或细胞外基质（ECM）重塑，或这些因素的组合，从而损害主动脉的结构和功能完整性。在AIM 1中，我们将使用双轴机械对野生型和BSMKO主动脉的测试以及微结构动机模型为了剖析平滑肌细胞的贡献，在基线时弹性蛋白和胶原蛋白对主动脉壁刚度并在收缩激动剂刺激之后。然后，我们将双轴测试的结果与分子相关联 VSM收缩，肌动蛋白聚合和焦点粘附蛋白的表达已知到VSM的音调和僵硬。在AIM 2中，我们将使用染色质免疫沉淀（CHIP） - 在 VSM匀浆以鉴定BCL11B VSM特异性DNA结合位点。我们还将检验假设 Bcl11b表观遗传通过募集组蛋白来调节MYH11和α-SMA基因表达脱乙酰基酶Sirtuin-1在其基因启动子中的g/c基序。在AIM 3中，我们将使用转基因小鼠或通过管理AAV2/5向量来确定的转化方法如果增加Bcl11b救援损害VSM收缩的VSM特异性分子机制和/或 VSM细胞 - 细胞矩阵相互作用（例如收缩蛋白，焦点粘合剂复合物，肌动蛋白聚合）在肥胖和老年小鼠中。 VSM刚度和脉搏波速度的最终下降， AS的体内索引将确定针对BCL11B是改善AS的可行策略从而防止CVD。