人Th17细胞中染色质长距离相互作用的大规模鉴定及其对Th17细胞分化和相关免疫疾病调控功能的研究

Th17 cell differentiation is a dynamic process in which expression of Th17 specific genes are regulated by the combination of transcription factors, epigenetic modification and higher order structures of chromatin, long-range promoter-enhancer chromatin interactions are key among these regulations. Genome-wide association studies yielded plenty of disease-associated SNP loci, the majority of them are located in noncoding regions and enriched in gene regulatory elements like enhancers ,but for most of them ,the target genes and mechanism of functions are unknown. This project is aiming to systematically study the long-range chromatin interactions between gene promoters and enhancers in Th17 cells with the state-of-art technology, ChIA-PET. In particular, this project will genome-widely identify the Th17 cell specific promoters and enhancers interactome, establish the correlations between chromatin interactions and gene transcription. Further, this project will knock down the expression of some important transcription factors in Th17 cells, like RORγt and STAT3 to investigate the molecular mechanisms of the regulatory roles of long-range chromatin interactions in Th17 cells. On the other hand, the project will use bioinformatics to find SNP loci overlapped with Th17 enhancers, then understand the functional mechanism and their regulation of Th17 differentiation by identifying the long range target genes of these immune disease-associated SNP loci. In a word, our project will not only help to better understand the mechanisms of how higher-order chromatin structure regulates gene transcription, but also provide great insight into regulatory pathways in the differentiation process of immune system and the mechanism of immune disease.

作为与粘膜防御和多种免疫疾病相关的重要T细胞亚群，Th17分化中特异性基因的表达受多水平调控，其中启动子增强子间染色质长距离相互作用的调节尤为重要，很多疾病相关SNP位点也坐落在基因调控序列如增强子的位置，其调控的目标基因和致病机理并不清楚。本项目拟利用最新的ChIA-PET技术大规模鉴定Th17细胞特异的染色质长距离相互作用位点，阐释染色质高级结构对细胞分化的调控功能；并利用RNAi技术下调Th17细胞中RORγt等重要转录因子的表达，研究对染色质长距离相互作用、基因表达等的影响，从而阐释染色质高级结构对细胞分化的调控机制。另一方面，利用生物信息学方法筛选坐落在Th17特异增强子位置的免疫疾病相关SNP位点及其目标基因，从而理解免疫疾病相关SNP的致病机理及对Th17分化的调控功能。本项目不仅有助于阐释染色质高级结构对基因转录的调控功能，对深入理解免疫细胞分化机制和疾病防治也有重要帮助。