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: 7804597
• 负责人: MICHAEL MILLER
• 金额: $ 18.9万
• 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/7804597
• 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（HDL-C）与冠状动脉疾病（CHD）之间存在反比关联。虽然已经据报道了导致低或不足的HDL-C的遗传变异，但很少有数据系统地评估了与寿命相关的高HDL-C状态。这是解决的重要问题，因为至少有50％的HDL-C是基因介导的。以前，我们的实验室专注于研究非常低的HDL胆固醇（例如，<20 mg/dl）的分子基础与早产冠心有关。在此期间，在20种基因中阐明的功能突变中的20个无关的血统中的16个中鉴定出低HDL-C的分子原因：载脂蛋白A-1（APOA1），ATP结合Cassette AI（ABCA1）和卵磷脂 - 胆固醇 - 胆固醇促脂脂蛋白脂肪固醇（LCAT）。相反，就家族性高脂蛋白血症（FHA）的分子基础而言，可用的信息较少，这是一种以非常高的HDL-C为特征的表型，包括超过100 mg/dl的水平。鉴于最近的数据表明，这是HDL在减少炎症和消退的动脉瘤病变中的推定作用，这是一个及时的研究领域。为此，我们收集并分析了来自FHA受试者的血液和DNA样本，其中有家族寿命的历史（至少有3名居住在90岁及以上的家庭成员）。尽管人们认识到基因组广泛的关联研究（GWAS）为评估人群水平上的基因型 - 表型关联提供了出色的管道，但本提案中要研究的受试者来自生物学上的小家族（n <10）。此外，对已知候选基因的基因组测序，然后进行SNP芯片分析（例如500K）未能揭示FHA的分子基础（请参阅下面的初步数据）。最近，通过合成（SB）大规模平行测序的使用已进化为一种新的且合适的突变方法，因为除了鉴定稀有和剪接变化的剂量外，该技术还允许测量感兴趣基因的转录物丰度和表达水平。此外，SBS将有助于区分SNP和因果突变。基于我们先前在识别引起HDL-C缺乏症的功能突变方面的成功，并且已经排除了导致FHA的已知候选基因突变（请参阅初步数据），我们相信使用SBS进行转录组重新方程提供了一个出色的平台，可以研究研究FHA分子基础与少数家庭成员的分子基础。因此，该R21提案的中心假设是HDL-C异常高是单基因突变的结果。我们的总体目的是确定与FHA最极端病例相关的新型突变，因为阐明FHA的遗传基础将为调查和促进我们对HDL调节蛋白与动脉粥样硬化性疾病之间复杂关系的理解提供基础。公共卫生相关性：总体而言，该应用程序旨在确定负责极高水平HDL（良好胆固醇）的基因。我们已经从几个无关的受试者那里收集了血液和DNA样本，这些受试者与家族寿命相关的HDL胆固醇（大于120 mg/dl）的血液和DNA样品。希望与寿命相关的高HDL状态的新基因的鉴定将有助于促进旨在减少心脏病的新型疗法的发展。