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

项目概要/摘要 炎症性肠病 (IBD) 之间的临床和遗传异质性表明 IBD 具有包容性 一系列粘膜炎症性疾病。预测疾病自然史和发展 亚组特异性治疗计划因深刻的遗传和病理生物学异质性而变得混乱，但 对于靶向治疗的开发至关重要。在未经选择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可能的不同患者亚群 受益于基于精确选择目标的新疗法。核糖核酸酶 T2 (RNASET2) 已被 被鉴定为潜在的 IBD 风险基因。临床上，RNASET2 疾病风险变异与 CD 相关 更复杂/耐药的疾病表型部分由治疗药物失败、治疗时间延长所定义 肠切除术、更短的再次手术时间以及术后内镜检查得分高 炎症指标。最近的数据证明了 RNASET2 和 另外两个基因 TNFSF15 和 ICAM1，GWAS 表明它们可能参与 炎症性肠病发病机制。 RNASET2疾病风险变异的基序筛选将rs2149092确定为潜在的 调节性单核苷酸多态性 (SNP) 预计会破坏共有的 ETS 转录因子 (TF) 结合位点位于增强子区域内。本提案要解决的假设是 确定包含 TL1A 介导的下调的调节机制和分子成分 RNASET2 表达的影响，以及有助于增强促炎细胞因子的分子事件 表达/分泌与 RNASET2 水平降低和随后 ICAM1 表达增强相关， 将产生更精确定义的严重 CD 形式的分子特征以及潜在目标， 然后可以单独或组合使用，以在规定的范围内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实现这一假设。 1) 确定TL1A涉及的候选调控变异体以及顺式和反式调控途径 介导的 RNASET2 表达抑制 2) 确定细胞和分子途径 RNASET2 表达减少会增强 LFA1/ICAM1 相互作用以及随后的 IFNg 分泌。 3） 通过以下方式验证具体目标 1 和 2 结果的功能影响：a) 使用等位基因特异性表达 从 CD 患者中分离出的 T 细胞中的 RNASET2 风险变异，以及 b) 测试候选治疗靶点 TL1A 过度表达的小鼠模型具有许多与 CD 相关的特征，更准确地说 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.