Genomics based approach for allergic disorderand development of innovative therapeutic strategy

初始的CD4T细胞分化为两个主要的辅助T细胞亚群，Th1和Th2，这是基于它们不重叠的细胞因子谱和免疫调节功能而定义的。Th1细胞分泌干扰素-γ和肿瘤坏死因子-α，负责细胞免疫和对细胞内病原体的保护；Th2细胞产生IL-4、IL-5、IL-6、IL-10和IL-13，介导体液免疫和抗蠕虫感染。小鼠Th2细胞因子基因座含有IL4、IL5、IL13，并结构性表达Rad50和Kif3a基因，其组成在哺乳动物中非常保守。Th2细胞因子的表达受顺式作用调控元件上转录允许和抑制染色质结构的遗传调节，这些结构已经通过检测DNaseI超敏(HS)位点和组蛋白修饰而得到实验鉴定。在小鼠Th2基因座中，IL 4的转录受与保守序列1(hss 1和hss 2…)对应的元件的调控Hs0位于IL4的5‘端，HS1位于启动子区域，HS2和HS3位于第二外显子，HS5a和HS5位于IL4的3’端。IL13基因包含两个启动子区域：HS1和HS2。HS1是近端启动子HS2上游保守的GATA-3反应元件(CGRE)。对IL-4调节区胚系缺失的小鼠的研究仍然没有解决每个调节区是否调节IL4转录或Th2分化的问题。我们的研究表明，IL4基因座上的HS2是一个关键的GATA-3结合位点，它调节着谱系特异性的IL-4的表达。HS2的缺失明显损害了H3K9/K14乙酰化的维持和IL4基因上H3K4甲基化的启动，这两者都是转录允许所必需的，导致IL4转录的缺乏。GATA-3的过表达未能弥补这些缺陷。我们发现，HS2作为GATA-3介导的IL-4基因座表观遗传修饰的特异性靶点，是不可或缺的增强子。因此，我们发现了一种新的GATA-3蛋白对Th2细胞因子基因的调控。较少

Naive CD4 T cells differentiate into two major subsets of helper T cells, Th1 and Th2, which are defined based on their non-overlapping cytokine profiles and immunoregulatory functions. Th1 cells secrete IFN-γ and TNF-α and are responsible for cell-mediated immunity and protection against intracellular pathogens, whereas Th2 cells produce IL-4, IL-5, IL-6, IL-10, and IL-13, and mediate humoral immunity and protection against helminthic infection. The mouse Th2 cytokine locus contains Il4, Il5, Il13, and the constitutively expressed Rad50 and Kif3a genes, and the locus composition is well conserved in mammals. Th2 cytokine expression is heritably regulated by transcriptionally permissive and repressive chromatin structure at cis-acting regulatory elements, which have been experimentally identified by the detection of DNaseI hypersensitive(HS) sites and histone modifications. In the mouse Th2 locus, Il4 transcription is regulated by elements that map to conserved sequence 1(HSS1 and HSS2 … More ), located between Il13 and Il4, HS0, located in the 5' region of Il4, HS1, located in the promoter region, HS2 and HS3 in the second exon, and HS5a and HS5, located 3' of Il4. The Il13 locus contains two promoter regions, HS1 and HS2. HS1 is the conserved GATA-3 response element(CGRE) upstream of the proximal promoter, HS2. Studies of IL-4 regulatory elements in mice with a germline deletion of these regulatory regions still leave open the question of whether each element regulates Il4 transcription or Th2 differentiation. Our study demonstrates that HS2 in the Il4 locus is a critical GATA-3 binding site that regulates lineage specific IL-4 expression. Deletion of HS2 markedly impaired maintenance of H3K9/K14 acetylation and the onset of H3K4 methylation on the Il4 locus, both of which are required for transcriptional permissibility, leading to the lack of Il4 transcription. GATA-3 overexpression failed to reconstitute these defects. We found that HS2, as a specific target of the GATA-3 mediated epigenetic modification on the Il4 locus, is an indispensable enhancer. Therefore, we found a novel regulation of Th2 cytokine genes by GATA-3 protein. Less