From the Department of Neurology and Neurosurgery (M.D.L., R.K., G.J.E., Y.M.R.), Hubrecht Institute-KNAW, and Division of Heart and Lungs, Department of Medical Physiology (J.B.), University Medical Center Utrecht, the Netherlands (M.D.L., M.W.V., M.P.C., J.B.); Department of Genetics, University Medical Center Groningen, University of Groningen, the Netherlands (J.J.d.B.-B.); Netherlands Institute for Neuroscience, Amsterdam (N.B.B.); and Division of Pediatrics, Wilhelmina Children's Hospital, Utrecht, the Netherlands (M.M.).
Stroke. 2018 Feb;49(2):447-453. doi: 10.1161/STROKEAHA.117.018557. Epub 2018 Jan 4.
Genome-wide association studies significantly link intracranial aneurysm (IA) to single-nucleotide polymorphisms (SNPs) in 6 genomic loci. To gain insight into the relevance of these IA-associated SNPs, we aimed to identify regulatory regions and analyze overall gene expression in the human circle of Willis (CoW), on which these aneurysms develop.
We performed chromatin immunoprecipitation and sequencing for histone modifications H3K4me1 and H3K27ac to identify regulatory regions, including distal enhancers and active promoters, in postmortem specimens of the human CoW. These experiments were complemented with RNA sequencing on the same specimens. We determined whether these regulatory regions overlap with IA-associated SNPs, using computational methods. By combining our results with publicly available data, we investigated the effect of IA-associated SNPs on the newly identified regulatory regions and linked them to potential target genes.
We find that IA-associated SNPs are significantly enriched in CoW regulatory regions. Some of the IA-associated SNPs that overlap with a regulatory region are likely to alter transcription factor binding, and in proximity to these regulatory regions are 102 genes that are expressed in the CoW. In addition, gene expression in the CoW is enriched for genes related to cell adhesion and the extracellular matrix.
CoW regulatory regions link IA-associated SNPs to genes with a potential role in the development of IAs. Our data refine previous predictions on SNPs associated with IA and provide a substantial resource from which candidates for follow-up studies can be prioritized.
全基因组关联研究显著将颅内动脉瘤（IA）与 6 个基因组位点的单核苷酸多态性（SNP）联系起来。为了深入了解这些与 IA 相关的 SNP 的相关性，我们旨在确定人类 Willis 环（CoW）中的调节区域，并分析其整体基因表达，这些动脉瘤就是在 CoW 上发展的。
我们对死后 CoW 标本进行了组蛋白修饰 H3K4me1 和 H3K27ac 的染色质免疫沉淀和测序，以识别调节区域，包括远端增强子和活跃启动子。这些实验还补充了相同标本的 RNA 测序。我们使用计算方法确定这些调节区域是否与 IA 相关的 SNP 重叠。通过将我们的结果与公开可用的数据相结合，我们研究了 IA 相关 SNP 对新鉴定的调节区域的影响，并将其与潜在的靶基因联系起来。
我们发现，IA 相关 SNP 在 CoW 调节区域中显著富集。与调节区域重叠的一些 IA 相关 SNP 可能改变转录因子结合，并且在这些调节区域附近有 102 个在 CoW 中表达的基因。此外，CoW 中的基因表达富集了与细胞黏附和细胞外基质相关的基因。
CoW 调节区域将 IA 相关 SNP 与在 IA 发展中具有潜在作用的基因联系起来。我们的数据细化了以前与 IA 相关的 SNP 的预测，并提供了一个重要的资源，可以从中优先选择后续研究的候选者。
