Role of Vascular Smooth Muscle Bcl11b in Arterial Stiffness

血管平滑肌 Bcl11b 在动脉僵硬中的作用

• 批准号: 9922405
• 负责人: Francesca Seta
• 金额: $ 3.57万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2023-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9922405
• 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; Biomechanics; Blood Vessels; Cardiovascular Diseases; ChIP-seq; Chromatin; Chromosomes, Human, Pair 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; cardiovascular disorder risk; cardiovascular risk factor; design; genome wide association study; in vivo; indexing; innovation; mechanical properties; mouse model; muscle stiffness; muscular structure; novel; novel therapeutic intervention; overexpression; polymerization; prevent; promoter; protein expression; recruit; standard measure; therapeutic evaluation; transcription factor; translational approach; vascular contributions; vasculogenesis

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.

动脉硬化(AS)，即弹性动脉中顺应性的进行性丧失，增加了 罹患心血管疾病(心血管疾病)。然而，AS的细胞和分子机制是 人们对此知之甚少。确定这些机制可能会导致创新战略，这些战略可能会减缓或 逆转AS，从而降低发生心血管疾病的风险。14号染色体上的一个基因沙漠基因座， 在基因Bcl11b下游，最近发现含有单核苷酸多态 (SNPs)与AS有非常显著的关联。我们是第一个展示击倒Bcl11b的人 小鼠(BSMKO)，无论是在全球范围内还是在血管平滑肌(VSM)中，都能引起AS升高， 并增加血管紧张素II诱导的主动脉瘤的发生率。此外，我们还展示了Bcl11b 高脂高蔗糖(HFHS)饲料喂养的两种AS模型小鼠的主动脉表达下调 和老年小鼠)，而Bcl11b转录调节收缩蛋白的表达，包括平滑 肌球蛋白(MYH11)和平滑肌α-肌动蛋白(α-SMA)。总而言之，我们假设 3‘-Bcl11b基因沙漠区的SNP变异调节和抑制Bcl11b的表达，发挥作用 在AS发病机制中的致病作用。 我们假设僵硬的大动脉降低了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， 从而损害了大动脉的结构和功能的完整性。在目标1中，我们将使用双轴机械 野生型和BSMKO主动脉与微结构驱动本构模型的联合测试 在基线状态下，分析平滑肌细胞、弹性蛋白和胶原蛋白在主动脉壁僵硬中的作用 并在收缩激动剂刺激后。然后我们将把双轴试验的结果与分子 VSM收缩、肌动蛋白聚合和粘着斑蛋白的表达 到VSM音调和僵硬。在目标2中，我们将使用染色质免疫沉淀(CHIP)测序 VSM匀浆鉴定Bcl11b VSM特异的DNA结合位点。我们还将检验这一假设 Bcl11b通过募集组蛋白对MYH11和α-SMA基因表达的表观调控 脱乙酰酶sirtuin-1在其基因启动子的G/C基序。在目标3中，我们将使用以下命令过度表达Bcl11b 转基因小鼠，或者更具翻译性的方法，通过注射AAV2/5载体来确定 如果增加Bcl11b可以挽救受损的VSM收缩和/或VSM特异性分子机制 VSM细胞-细胞外基质相互作用(例如，收缩蛋白、焦点黏附复合体、肌动蛋白 聚合)在肥胖和衰老的小鼠中。VSM硬度和脉搏波速度明显降低， AS的体内指标将确定靶向Bcl11b是改善AS的可行策略 从而预防心血管疾病。