Molecular characterization of the role of RNASET2 in Severe Crohn's Disease

项目概要/摘要 炎症性肠病（IBD）的临床和遗传异质性表明IBD是包容性的 一系列粘膜炎性疾病的症状预测疾病的自然史和发展 亚组特异性治疗计划受到深刻的遗传和病理生物学异质性的混淆， 对靶向治疗的发展至关重要。药物开发在糖尿病患者人群中的应用 只取得了有限的成功。需要新的方法来定义不同的患者亚群， 受益于基于精确选择的目标的新疗法。核糖核酸酶T2（RNASET 2）已被 被认为是IBD的潜在危险基因。在临床上，RNASET 2疾病风险变体与CD中的 更复杂/耐药的疾病表型，部分由治疗药物失败定义， 肠切除术，更短的时间再次手术和术后内窥镜检查， 炎症指标最近的数据表明RNASET 2和RNASET 3之间的功能和生物学关系。 另外两个基因，TNFSF 15和ICAM 1，已经被GWAS暗示为可能参与 IBD发病机制。RNASET 2疾病风险变体的基序筛选确定rs 2149092为潜在的 预测可破坏共有ETS转录因子的调节性单核苷酸多态性（SNP） (TF)位于增强子区域内的结合位点。本提案所要解决的假设是， 鉴定包括TL 1A介导的下调的调节机制和分子组分 RNASET 2表达，以及促进促炎细胞因子增强的分子事件 与RNASET 2水平降低和随后ICAM 1表达增强相关的表达/分泌， 将产生更精确定义的严重CD形式的分子特征以及潜在靶点， 然后可以单独或组合使用，以最佳地减轻严重疾病的发展， 克罗恩病（CD）患者的子集。我们将通过以下具体目标来探讨这一假设。 1)确定TL 1A中涉及的候选调控变体以及顺式和反式调控途径 2）确定RNASET 2表达的细胞和分子途径， 降低的RNASET 2表达驱动增强的LFA 1/ICAM 1相互作用和随后的IFNg分泌。第三章 通过以下方式验证特定目的1和2的发现的功能影响：a）使用等位基因特异性表达 和B）测试从CD患者分离的T细胞中的候选治疗靶标， TL 1A过表达的小鼠模型具有许多与CD相关的特征， 定义分子特征，并进一步完善严重疾病的潜在治疗靶点。

PROJECT SUMMARY/ABSTRACT Clinical and genetic heterogeneity among the inflammatory bowel diseases (IBD) suggests that IBD is inclusive of a spectrum of mucosal inflammatory diseases. Predicting disease natural history and development of subgroup-specific treatment plans are confounded by profound genetic and patho-biologic heterogeneity, but is essential to the development of targeted therapies. Drug development in unselected patient populations has had only limited success. Novel approaches are needed to define the distinct patient subpopulations likely to benefit from new treatments based on precisely selected targets. Ribonuclease T2, (RNASET2) has been identified as a potential IBD risk gene. Clinically, RNASET2 disease risk variants are associated in CD with a more complicated/resistant disease phenotype defined in part by therapeutic drug failure, increase in length of intestinal resection, a shorter time to reoperation and post-operative endoscopy with high scores in inflammation indices. Recent data demonstrate a functional and biological relationship between RNASET2 and two additional genes, TNFSF15 and ICAM1, which have been implicated by GWAS as potentially involved in IBD pathogenesis. Motif screening of RNASET2 disease risk variants identified rs2149092 as a potential regulatory single nucleotide polymorphism (SNP) predicted to disrupt a consensus ETS-transcription factor (TF) binding site located within an enhancer region. The hypothesis to be addressed in this proposal is that identifying the regulatory mechanisms and molecular components comprising TL1A-mediated down-regulation of RNASET2 expression, and the molecular events contributing to enhancement of pro-inflammatory cytokine expression/secretion related to decreased levels of RNASET2 and subsequent enhanced ICAM1 expression, will yield a more precisely defined molecular signature of a severe form of CD as well as potential targets, that may then be used alone or in combination to optimally mitigate severe disease development in a defined subset of patients with Crohn’s disease (CD). We will approach this hypothesis by the following Specific Aims. 1) Determine the candidate regulatory variants and cis-and trans-regulatory pathways involved in TL1A mediated inhibition of RNASET2 expression 2) Determine the cellular and molecular pathways by which decreased RNASET2 expression drives enhanced LFA1/ICAM1 interaction and subsequent IFNg secretion. 3) Validate the functional impact of the findings from Specific Aims 1 and 2 by: a) using allele specific expression of RNASET2 risk variants in T cells isolated from CD patients and b) testing candidate therapeutic targets in mouse models of TL1A overexpression with many of the characteristics associated with CD to more precisely define molecular signatures and further refine potential therapeutic targets for severe disease.