A GENOME-WIDE METHYLATION STUDY ON ESSENTIAL HYPERTENSION

描述(由申请人提供)： 从最近的‘全基因组关联研究’，我们不得不得出结论，初级DNA序列的参与并不能解释原发性高血压(EH)的全部遗传易感性。更透彻地了解EH可能涉及的其他机制是预防和开发新疗法的先决条件。DNA甲基化的改变(即遗传信息的表观遗传修饰)可以在正常和病理的细胞过程中发挥重要的调节作用(通过影响转录)。根据最近的许多研究，强调炎症参与了EH的发展，我们假设白细胞DNA甲基化的变化参与了EH的发病。我们的目标是使用一种多步骤全基因组方法来识别这些差异甲基化位点。首先，我们将确定EH患者和对照组之间DNA甲基化不同的CpG位点(目标1)。我们将采用一步一步的选择过程，包括3个阶段。在询问了100对不符合EH(识别疾病相关表观遗传信号的理想实验模型)的同卵双胞胎对的14,000多个基因的27,000个甲基化位点和从芬兰双胞胎队列研究中选择的100个年龄和性别匹配的外部对照后，我们将选择最有希望在500例EH患者和500名健康对照中进行验证和复制。然后，我们将确定这些CpG位点甲基化的变化是否与细胞中基因表达的变化有关。还将进行体外功能实验，以研究这些CpG位点的去甲基化是否可以激活基因表达，这最终将导致(大约)20个最重要的位点。接下来，我们将在嵌套病例对照环境(380例新发展的EH病例和380例对照)中确定DNA甲基化状态和EH之间的时间关系，包括评估基线时的甲基化状态和4年后的EH状态(目标2)。此外，我们将在血压压力队列中确定DNA甲基化状态对血压发育的影响，该队列在11年的随访中对299名高加索青少年进行了8次血压测量(目标3)。次级特定目标将在杰克逊心脏研究和BP压力队列中测试在高加索人中发现的甲基化位点是否也与非裔美国人高血压的发病有关。我们期望精确定位可能参与EH病理生理学的特定甲基化位点。这些结果可能在早期风险分层和干预的新治疗靶点的开发中发挥关键作用。

DESCRIPTION (provided by applicant): From the recent 'genome-wide association studies' we have to conclude that the involvement of the primary DNA sequence does not explain the full genetic predisposition of essential hypertension (EH). A more thorough understanding of additional mechanisms potentially involved in EH is a prerequisite to prevention and development of novel therapies. Changes in DNA methylation (i.e., epigenetic modification of genetic information) can play an important regulatory role (by influencing transcription) in both normal and pathological cellular processes. Based on many recent studies that highlight the involvement of inflammation in the development of EH, we hypothesize that changes in DNA methylation of leukocytes are involved in the pathogenesis of EH. We aim to identify these differentially methylation sites using a multi-step genome wide approach. First, we will identify the CpG sites where DNA methylation differs between EH cases and controls (aim 1). We will employ a step-wise selection process involving 3 stages. After interrogation of 27,000 methylation sites in more than 14,000 genes in 100 monozygotic twin pairs discordant for EH (the the ideal experimental model for identifying disease related epigenetic signals) and 100 age and gender matched external controls selected from the Finnish Twin Cohort Study, we will choose the most promising for validation and replication in 500 EH cases and 500 healthy controls. Then, we will determine whether changes in methylation of these CpG sites are associated with changes in gene expression in the cells. Functional in vitro experiments will also be conducted to investigate whether demethylation of these CpG sites can activate gene expression, which will eventually leading to the (approximately) 20 most important sites. Next, we will determine the temporal relationship between DNA methylation status and EH in a nested case-control setting (380 newly developed EH cases and 380 controls) involving assessment of methylation status at baseline and EH status after 4 years follow-up (aim 2). Furthermore, we will determine the effect of DNA methylation status on blood pressure development in the BP stress cohort which has measured BP 8 times in 299 Caucasian adolescents during 11 years follow up (aim 3). Secondary specific aim will test whether the methylation sites identified in Caucasians are also involved in the pathogenesis of EH in African Americans in the Jackson Heart Study and the BP stress cohort. We expect to pinpoint specific methylation sites likely to be involved in the pathophysiology of EH. These results might play a key role in the development of new therapeutic targets for early risk stratification and intervention.