Functional epigenomic dissection of genetic generalized epilepsies

遗传性广泛性癫痫（GGEs）是遗传性癫痫最常见的形式。迄今为止，常见GGE综合征的遗传基础由于其突出的多基因易感性和广泛的遗传异质性在很大程度上仍未得到解决。遗传力分析表明，至少35%的GGE易感性是由单核苷酸多态性（snp）决定的。全基因组关联研究（GWASs）仅鉴定出少数主要位于非编码基因组区域的ge风险位点，提示因果snp对基因表达具有顺式调控作用。该项目旨在通过对GGE的GWAS风险位点和癫痫发生相关候选基因衍生的候选snp进行表观基因组分析，剖析与GGE风险相关的调控snp （rsnp）。候选rsnp将通过与转录因子、mirna和lncrna结合位点的基因组交叉来优先排序，这些转录因子、mirna和lncrna位于调节基因表达的脑和细胞类型特异性表观遗传元件中。最有希望的候选rSNPs的功能验证将评估rSNPs对人类海马活组织中基因表达（表达数量性状位点，eQTL）和CpG甲基化（甲基化QTL， meQTL）的顺式调控定量效应，并使用荧光素酶报告基因分析在初级神经元中进行体外基因表达分析。随后，通过室内子宫电穿孔（IUE）介导的转基因小鼠报告基因实验将通过体内分子成像来探索基因启动子rSNPs的等位基因效应。首先，将建立功能验证方法，用于预测影响两个已知癫痫基因（CaV3.2/CACNA1H， PIGP）启动子活性的候选rsnp。总之，gge相关rsnp的表观基因组分析将获得对癫痫发生的时空神经生物学过程的重要见解。癫痫发生关键通路的预测建模和GGE个体表观基因组风险谱的描绘可能与精准医学相关。

Genetic generalized epilepsies (GGEs) represent the most common form of genetically determined epilepsies. Up to date, the genetic basis of common GGE syndromes remains largely unsolved due to their prominent polygenic predisposition and extensive genetic heterogeneity. Heritability analyses implicate that at least 35% of GGE susceptibility is determined by single nucleotide polymorphisms (SNPs). Genome-wide association studies (GWASs) have identified only few GGE-risk loci mainly in non-coding genomic regions, suggesting cis-acting regulatory effects of the causal SNPs on gene expression. This project aims to dissect regulatory SNPs (rSNPs) conferring risk of GGE by epigenomic profiling of candidate SNPs derived from GWAS risk loci of GGE and candidate genes implicated in epileptogenesis. Candidate rSNPs will be prioritized in silico by their genomic intersection with binding sites of transcription factors, miRNAs and lncRNAs located within brain- and cell type-specific epigenetic elements regulating gene expression. Functional validation of the most promising candidate rSNPs will evaluate the cis-regulatory quantitative effects of rSNPs on gene expression (expression quantitative trait locus, eQTL) and CpG methylation (methylation QTL, meQTL) in human hippocampal biopsies, and in vitro gene expression analyses in primary neurons using luciferase reporter assays. Subsequently, intraventricular in utero electroporation (IUE)-mediated transgenic mouse reporter assays will explore the allelic effects of gene promoter rSNPs by in vivo molecular imaging. Initially, functional validation methods will be established for candidate rSNPs predicted to affect the promoter activity of two known epilepsy genes (CaV3.2/CACNA1H, PIGP). Together, epigenomic profiling of GGE-associated rSNPs will gain critical insights into temporospatial neurobiological processes of epileptogenesis. Predictive modeling of key pathways of epileptogenesis and delineation of individual epigenomic risk profiles of GGE may be of relevance towards precision medicine.