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）：人群研究一致证明高密度脂蛋白胆固醇 (HDL-C) 与冠心病 (CHD) 之间呈负相关。虽然有报道称，导致 HDL-C 低或缺乏的遗传变异与过早冠心病有关，但很少有数据系统评估高 HDL-C 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 HDL-C 是由基因介导的。此前，我们的实验室重点研究极低 HDL 胆固醇（例如 < 20 mg/dL）与早发冠心病相关的分子基础。在此期间，在 20 个不相关家系中的 16 个中确定了低 HDL-C 的分子原因，并在 3 个基因中阐明了功能突变：载脂蛋白 A-1 (APOA1)、ATP 结合盒 AI (ABCA1) 和卵磷脂胆固醇酰基转移酶。 LCAT）。相比之下，关于家族性高 α 脂蛋白血症 (FHA) 的分子基础的信息要少得多，FHA 是一种以非常高的 HDL-C 为特征的表型，包括水平超过 100 mg/dL。鉴于最近的数据表明 HDL 在减少炎症和消退动脉粥样硬化病变方面的推定作用，这是一个及时的研究领域。为此，我们收集并分析了具有长寿家族史（至少 3 名家庭成员活到 90 岁及以上）的 FHA 受试者的血液和 DNA 样本。虽然人们认识到全基因组关联研究（GWAS）为评估人群水平的基因型-表型关联提供了一个出色的渠道，但本提案中要研究的受试者来自生物学上的小家庭（n < 10）。此外，对已知候选基因进行基因组测序并进行 SNP 芯片分析（例如 500K）未能揭示 FHA 的分子基础（参见下面的初步数据）。最近，大规模并行合成测序（SBS）的使用已发展成为一种新的、合适的突变发现方法，因为除了鉴定稀有变体和剪接变体之外，该技术还可以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 SNP 和致病突变。基于我们之前成功识别导致 HDL-C 缺乏的功能突变，并且已经排除了导致 FHA 的已知候选基因的突变（参见初步数据），我们相信使用 SBS 的转录组重测序为研究 FHA 的分子基础提供了一个极好的平台。家庭成员很少的血统。因此，R21 提案的中心假设是异常高的 HDL-C 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增进我们对 HDL 调节蛋白与动脉粥样硬化血栓性疾病之间复杂的逆关系的理解奠定基础。公共健康相关性：总体而言，本申请旨在识别导致高密度脂蛋白（“好胆固醇”）水平极高的基因。我们从几位不相关的受试者身上收集了血液和 DNA 样本，这些受试者的 HDL 胆固醇水平极高（大于 120 毫克/分升），且与长寿家族史相关。希望鉴定与长寿相关的高 HDL 状态相关的新基因将有助于开发旨在减少心脏病的新疗法。