Unraveling the Genetic Architecture of Very High HDL cholesterol though Transcrip

通过转录揭示极高 HDL 胆固醇的遗传结构

• 批准号: 7573237
• 负责人: MICHAEL MILLER
• 金额: $ 15.75万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7573237
• 关键词: Age; Apolipoprotein A-I; Architecture; Area; Arterial Fatty Streak; Binding; Blood; Candidate Disease Gene; Cholesterol; Complex; Coronary heart disease; DNA; DNA Resequencing; Data; Development; Disease; Family; Family history of; Family member; Foundations; Gene Expression Profile; Gene Mutation; Genes; Genetic; Genetic Variation; Genomics; Genotype; Heart Diseases; High Density Lipoprotein Cholesterol; High Density Lipoproteins; Individual; Inflammation; Investigation; Laboratories; Lesion; Life; Longevity; Measurement; Mediating; Molecular; Mutation; Phenotype; Phosphatidylcholine-Sterol O-Acyltransferase; Population; Population Study; RNA Splicing; Recording of previous events; Reporting; Role; Sampling; Technology; Testing; Transcript; Variant; base; genetic association; genetic pedigree; genetic regulatory protein; genome wide association study; interest; novel; premature; public health relevance; success

DESCRIPTION (provided by applicant): Population studies have consistently demonstrated an inverse association between high-density lipoprotein cholesterol (HDL-C) and coronary heart disease (CHD). While genetic variation causing low or deficient HDL-C has been reported with premature CHD, few data have systematically evaluated high HDL-C states in association with longevity. This is an important issue to resolve because at least 50% of HDL-C is genetically mediated. Previously, our laboratory focused on studying the molecular basis of very low HDL cholesterol (e.g., < 20 mg/dL) in association with premature CHD. During that period, the molecular cause of low HDL-C was identified in 16 of 20 unrelated pedigrees with functional mutations elucidated in 3 genes: apolipoprotein A-1 (APOA1), ATP-binding cassette AI (ABCA1) and lecithin-cholesterol acyltransferase (LCAT). In contrast, considerably less information is available in regard to the molecular basis of familial hyperalphalipoproteinemia (FHA), a phenotype characterized by very high HDL-C, including levels that exceed 100 mg/dL. This is a timely area for investigation in view of recent data demonstrating a putative role for HDL in reducing inflammation and regressing atheromatous lesions. To this end, we collected and analyzed blood and DNA samples from subjects with FHA in whom a familial history of longevity (at least 3 family members living to age 90 years and beyond) exists. While it is recognized that genome wide association studies (GWAS) provide an outstanding conduit for assessing genotype-phenotype associations at the population level, the subjects to be investigated in the present proposal are derived from biologically small families (n < 10). Moreover, genomic sequencing of known candidate genes followed by SNP chip analysis (e.g., 500K) failed to reveal the molecular basis of FHA (see preliminary data, below). Recently, the use of Massively Parallel Sequencing by Synthesis (SBS) has evolved as a new and suitable approach for mutation discovery because in addition to identifying rare and splice-variants, this technology permits measurement of transcript abundance and expression levels of genes of interest. Moreover, SBS will assist in discriminating between SNPs and causative mutations. Based upon our prior success in identifying functional mutations causing HDL-C deficiency and having already ruled out mutations in known candidate genes causing FHA (see preliminary data), we believe that transcriptome resequencing using SBS provides an excellent platform to study the molecular basis of FHA in pedigrees with few family members. Therefore, the central hypothesis of this R21 proposal is that exceptionally high HDL-C is a consequence of single-gene mutations. Our overall aim is to identify novel mutations associated with the most extreme cases of FHA because elucidating the genetic underpinnings of FHA will provide the foundation to investigate and advance our understanding of the complex inverse relationship between HDL regulatory proteins and atherothrombotic disease. PUBLIC HEALTH RELEVANCE: Overall, this application seeks to identify the gene(s) responsible for extremely high levels of HDL, the "good cholesterol". We have collected blood and DNA samples from several unrelated subjects who have extraordinarily high levels of HDL cholesterol (greater than 120 mg/dL) in association with a family history of longevity. It is hoped that the identification of novel genes implicated in high HDL states that are associated with longevity will facilitate the development of novel therapies aimed at reducing heart disease.

描述(由申请人提供)：人群研究一直表明高密度脂蛋白胆固醇(HDLC)和冠心病(CHD)之间存在负相关。虽然早产儿CHD患者高密度脂蛋白胆固醇水平低或不足的遗传变异已有报道，但很少有数据系统地评估高高密度脂蛋白胆固醇状态与长寿的关系。这是一个需要解决的重要问题，因为至少50%的高密度脂蛋白-C是由基因介导的。此前，我们的实验室专注于研究极低的高密度脂蛋白胆固醇(例如，20 mg/dL)与早产儿冠心病相关的分子基础。在此期间，在20个无关的家系中，有16个被证实有3个基因的功能突变：载脂蛋白A-1(APOA1)、三磷酸腺苷结合盒AI(ABCA1)和卵磷脂-胆固醇酰基转移酶(LCAT)，从而确定了低HDLc的分子原因。相比之下，关于家族性高脂蛋白血症(FHA)的分子基础的信息要少得多，FHA是一种表型，其特征是高密度脂蛋白-C，包括超过100 mg/dL的水平。鉴于最近的数据显示高密度脂蛋白在减少炎症和动脉粥样硬化病变消退中的假定作用，这是一个及时的研究领域。为此，我们收集并分析了患有FHA的受试者的血液和DNA样本，这些受试者中有长寿家族史(至少有3名家庭成员活到90岁及以上)。虽然人们认识到全基因组关联研究为在种群水平上评估基因-表型关联提供了一个很好的渠道，但本提案中要调查的对象来自生物学上的小家庭(n&lt；10)。此外，对已知候选基因进行基因组测序，然后进行SNP芯片分析(例如，500K)，未能揭示FHA的分子基础(见下文的初步数据)。最近，大规模合成并行测序技术(SBS)的使用已经发展成为一种新的、适合于突变发现的方法，因为除了识别稀有和剪接变异外，这项技术还允许测量感兴趣基因的转录丰度和表达水平。此外，SBS将有助于区分SNPs和致病突变。基于我们之前在识别导致高密度脂蛋白胆固醇缺乏的功能突变方面的成功，并已经排除了导致FHA的已知候选基因的突变(见初步数据)，我们认为，使用SBS进行转录组重新测序为研究家庭成员较少的家系中FHA的分子基础提供了一个很好的平台。因此，R21建议的中心假设是，异常高的高密度脂蛋白胆固醇是单基因突变的结果。我们的总体目标是识别与最极端的FHA病例相关的新突变，因为阐明FHA的遗传基础将为研究和推进我们对高密度脂蛋白调节蛋白与动脉粥样硬化血栓形成疾病之间复杂的反向关系的理解提供基础。与公众健康相关：总的来说，这项申请旨在确定导致高密度脂蛋白水平极高的基因(S)，这是一种“好胆固醇”。我们收集了几个无关受试者的血液和DNA样本，这些受试者的高密度脂蛋白水平(大于120 mg/dL)与家族长寿史有关。人们希望，在高密度脂蛋白状态下发现与长寿相关的新基因，将有助于开发旨在减少心脏病的新疗法。