Lupus Association with Signal Transducer and Activator of Transcription 4

描述（由申请人提供）： 在最近发现的与系统性红斑狼疮相关的许多基因中，STAT 4中的单倍型是HLA区域之外最强大的基因之一。STAT 4是一种重要的炎症转录因子，其在细胞中的水平决定了炎症反应的程度。 对STAT 4控制的基因的反应。这种关联是奇怪的，因为它位于第四内含子中，而DN的这一片段与STAT 4的功能或活性的关系的生物学相关性知之甚少。我们的初步研究和最近的文献表明，风险等位基因表达更高水平的STAT 4 mRNA和蛋白，并导致对干扰素-<$（IFN-<$）的敏感性增加。导致STAT 4与狼疮相关的变异位于55.5kb单倍型中。DNA测序已经确定了风险和非风险单倍型之间的许多差异。我们将整合新的基因分型和DNA测序数据，现在正在生成一个完整的地图，定义包含因果变异的基因组边界，并确定所有可能的变异， 有助于疾病风险和缩短间隔（目标1）。接下来，由于疾病风险似乎与表达相关，我们将探索组蛋白标记和DNA甲基化的序列特异性表观遗传改变，以确定风险单倍型的区域，这些区域准备增加STAT 4 mRNA的产生（目的2）。这将是表观遗传学在等位基因特异性基因定位和候选因果变异鉴定中的一种新应用，如果成功的话，将具有通过改变表达水平来鉴定改变疾病风险的基因变异的一般应用。我们将评估转录因子的差异结合是STAT 4基因表达差异的原因这一假设，并采用信息学方法识别控制基因表达的潜在风险单倍型差异，并通过应用体外方法确定哪些已识别的变体实际上是基因表达变化的原因（目的3）。我们期望确定STAT 4中的因果变异，并解释产生狼疮风险的机制的一些重要细节。最后，在整个拟议的STAT 4研究计划中，我们将逐步探索更复杂的策略，以降低风险单倍型中增加的STAT 4活性（目标4）。最初，我们将探索已知抑制剂（lisopfylline，姜黄素和他汀类药物）对STAT 4活性的潜在影响。在该项目的后期，在我们鉴定出候选的因果转录因子后，我们将用慢病毒载体递送特异性shRNA以抑制候选的因果转录因子的作用，这可能有可能降低风险等位基因增加的STAT 4表达，使风险单倍型的表达水平接近非风险等位基因的STAT 4表达，从而，降低狼疮的风险。STAT 4还与类风湿性关节炎、克罗恩病和1型糖尿病有关，因此，理解STAT 4在自身免疫中的机制的任何努力都具有广泛的重要性，特别是如果这些知识能够使我们更接近于针对这些疾病的免疫功能障碍的更有效和更特异的疗法。

DESCRIPTION (provided by applicant): Of the many genes recently discovered to be associated with Systemic Lupus Erythematosus the haplotype in STAT4 is among the most powerful outside the HLA region. STAT4 is an important inflammatory transcription factor with the level in the cell determining the magnitude of the response to the genes that STAT4 controls. This association is curious because it is localized in the fourth intron and the biological relevance of the relationship of this piece of DN to the function or activity of STAT4 is poorly understood. Our preliminary together with recent literature show that the risk allele expresses a higher level of STAT4 mRNA and protein and leads to increased sensitivity to Interferon-¿ (IFN-¿). The variant causing the association with lupus in STAT4 is located in a 55.5kb haplotype. DNA sequencing has defined many differences between the risk and non-risk haplotype. We will incorporate new genotyping and DNA sequencing data available and now being generated into a complete map, defining the genomic boundaries containing the causal variant(s) and identifying all of the possible variants that could contribute to disease risk and reducing the interval (Aim 1). Next, since disease risk appears to be related to expression, we will explore sequence specific epigenetic alterations in histone marks and DNA methylation to identify the regions of the risk haplotype that are poised for increased STAT4 mRNA production (Aim 2). This will be a novel application of epigenetics for allele specific gene mapping and candidate causal variant identification that if successful will have general application for identifying gene variants that change disease risk by changing expression level. We will evaluate the hypothesis that the differential binding of transcription factors are responsible for the difference in STAT4 gene expression with informatic approaches to identify potential risk haplotype differences controlling gene expression and by applying in vitro methods to establish which of the identified variants is actually responsible for the change in gene expression (Aim 3). We anticipate identifying the causal variant in STAT4 and explaining some of the important details of the mechanism that generates risk for lupus. Finally, throughout the proposed program of research on STAT4 we will explore progressively more sophisticated strategies for decreasing the increased STAT4 activity in the risk haplotype (Aim 4). Initially, we will explore the potential impact on STAT4 activity with the known inhibitors (lisopfylline, curcumin, and statins). Later in the program and after we identify candidate causal transcription factors, we will deliver specific shRNA with lentivirus vectors to inhibit the actionof the candidate causal transcription factor(s), which may have the potential to reduce the increased STAT4 expression of the risk allele, returning the level of expression of the risk haplotype close to the STAT4 expression of the non-risk allele and, thereby, reducing the risk of lupus. STAT4 also is associated with rheumatoid arthritis, Crohn's disease, and type 1 diabetes, giving broad importance to any effort to understand STAT4 mechanism in autoimmunity, especially if this knowledge were to bring us closer to more effective and specific therapies for the immune dysfunction of these diseases.