Histone Deacetylase Inhibitors and Inflammatory Bowel Disease

描述（由申请人提供）： 该提案描述了一项全面的培训计划，旨在将de Zoeten博士从一名指导科学家转变为儿科GI和肝病领域的独立研究者。他将专注于炎症性肠病（IBD）的免疫病理学研究，最终目的是改善这种和其他复杂的肠道疾病。在这些研究过程中，PI将获得实验室技能、研究培训和关键试剂，使其能够开始作为独立医生/科学家工作。炎症性肠病（IBD）涉及粘膜T细胞的失调。目前，人们对天然存在的CD 4 + CD 25+调节性T细胞（T细胞）作为调节炎症的试剂的功能非常感兴趣，T细胞通过CD 25的基线表达和FoxpS的细胞内表达而与其他CD 4+细胞区分开。组蛋白去乙酰化酶（HDAC）是使赖氨酸残基去乙酰化并通过染色质缩合诱导转录抑制的酶。当HDAC被抑制时，组蛋白尾部上的赖氨酸残基变得高度乙酰化，染色质变得可用于转录因子结合，并发生基因转录。现在还认识到，非染色质蛋白质可以通过乙酰化和去乙酰化来调节。组蛋白去乙酰化酶抑制剂（HDACi）通常结合HDAC的催化位点，阻断底物进入，从而允许组蛋白乙酰化和基因转录。虽然HDACi主要被评估为抗癌药物，但它们也在炎症模型中进行了评估。我们计划利用这些化合物治疗IBD。拟定研究将评估HDACi（包括曲古抑菌素A（TsA）、琥珀酰苯胺羟肟酸（SAHA）和/或丙戊酸盐）在3种不同结肠炎模型中的作用。我们还将使用这些模型来确定哪些HDAC参与结肠炎，以及TdR是否对HDACi对结肠炎的有益作用至关重要。我们已经注意到用TsA处理小鼠与FoxpS乙酰化相关，因此我们将通过Foxp 3上关键赖氨酸的诱变来评估HDACi的作用是否依赖于那些位点的乙酰化。最后，我们注意到多种HDAC在活化的TGFAP中升高，并计划检查这些HDAC的相对重要性，以评估未来是否需要选择性HDACi治疗。相关性：从这次和未来的研究中获得的信息将提高我们对IBD的免疫病理学以及调节性T细胞的表观遗传调节的理解，并可能增强这种疾病的治疗和预防并发症。

DESCRIPTION (provided by applicant): This proposal describes a comprehensive training program to transition Dr. de Zoeten from a mentored scientist into an independent investigator in the area of Pediatric Gl and Hepatology. He will focus on the study of the immunopathology of inflammatory bowel disease (IBD), with the ultimate purpose of ameliorating this and other complex intestinal disorders. Over the course of these studies, the PI will acquire laboratory skills, research training, and critical reagents which will enable him to begin work as an independent physician/scientist. Inflammatory bowel disease (IBD) involves dysregulation of mucosal T cells. There is currently much interest in the functions of naturally occurring CD4+CD25+ regulatory T cells (Tregs) - distinguished from other CD4+ cells by baseline expression of CD25 and intracellular expression of FoxpS - as agents to regulate inflammation. Histone deacetylases (HDACs) are enzymes that deacetylate lysine residues and induce transcriptional repression through chromatin condensation. When HDACs are inhibited, lysine residues on histone tails become hyperacetylated, chromatin becomes accessible for transcription factor binding and gene transcription occurs. It is now also recognized that non-chromatin proteins can be regulated by acetylation and de-acetylation. Histone deacetylase inhibitors (HDACi) typically bind the catalytic sites of HDACs, blocking substrate access, thereby allowing histone acetylation and gene transcription. While HDACi are mainly being evaluated as anti-cancer agents, they have also been evaluated in models of inflammation. We plan to utilize these compounds in the treatment of IBD. The proposed studies will assess the effects of HDACi, including Trichostatin A (TsA), Suberolylanilide hyroxamic acid (SAHA) and/or valproate in 3 different models of colitis. We will also use these models to determine which HDACs are involved in colitis, and whether Tregs are critical to the beneficial effects of HDACi on colitis. We have noted that treatment of mice with TsA is associated with FoxpS acetylation and we will therefore evaluate, through mutagenesis of key lysines on Foxp3, if the effects of HDACi is dependent upon acetylation of those sites. Finally, we note multiple HDACs are elevated in activated Tregs and plan to examine the relative importance of these HDACs so as to assess whether future selective HDACi therapy may be warranted. Relevance: The information which will be obtained from this and future investigations will improve our understanding of the immunopathology of IBD, as well as the epigenetic regulation of regulatory T cells, and may enhance the therapy and prevent complications of this disease.