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

项目摘要/摘要 炎症性肠病(IBD)的临床和遗传异质性表明IBD具有包容性 一系列的粘膜炎症性疾病。预测疾病的自然历史和发展 针对亚群的治疗计划被严重的遗传和病理生物异质性所混淆，但 对于靶向治疗的发展至关重要。在未选定的患者群体中进行药物开发 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治疗方法。核糖核酸酶T2(RNASET2)已被 被确定为潜在的IBD风险基因。临床上，RNASET2疾病风险变异在CD中与 更复杂/更耐药的疾病表型部分由治疗药物失败定义，长度增加 肠切除，再次手术和术后内窥镜检查时间较短，得分高 炎症指标。最近的数据表明RNASET2和RNASET2之间存在功能和生物学上的关系 另外两个基因，TNFSF15和ICAM1，已经被GWAS认为可能参与了 IBD发病机制。RNASET2疾病风险变异体的基序筛选确定rs2149092为潜在的 调节性单核苷酸多态(SNP)被预测为破坏一致的Ets-转录因子 (Tf)位于增强子区域内的结合位点。这项建议中要解决的假设是 确定TL1a介导的下调的调控机制和分子组成 RNASET2的表达，以及促进促炎细胞因子增强的分子事件 表达/分泌与RNASET2水平降低和随后ICAM1表达增强有关， 将产生一个更精确地定义的CD的严重形式的分子签名以及潜在的靶标， 然后可以单独使用或联合使用，以最佳地缓解定义的 克罗恩病(CD)患者的亚组。我们将通过以下具体目标来探讨这一假设。 1)确定TL1a中涉及的候选调控变异体以及顺式和跨式调控途径 介导的RNASET2表达抑制2)决定细胞和分子通路，通过 RNASET2表达降低可促进LFA1/ICAM1相互作用和随后的IFNG分泌。3) 通过：a)使用等位基因特异性表达来验证来自特定目标1和2的发现的功能影响 从CD患者分离的T细胞中RNASET2风险变异体的研究以及b)测试候选治疗靶点 小鼠模型中TL1a的过度表达与CD的许多特征相关联，以更准确地 定义分子特征并进一步细化严重疾病的潜在治疗目标。

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.