Modulation of intestinal inflammation in colitis by manipulating dendritic cells

描述（申请人提供）：炎症性肠病（IBD）是一种慢性复发性炎症性疾病;其发病机制涉及的因素包括患者的遗传背景、肠道内细菌或病原菌的影响以及先天性和适应性免疫应答的异常激活。树突状细胞（DC）似乎在调节先天性和适应性免疫应答中起作用。来自肠固有层的DC使用模式识别受体（例如Toll样受体（TLR））识别细菌组分并对其作出应答。TLR检测保守的微生物组分的独特库，因此它们可以共同检测大多数微生物。TLR被微生物的特定组分激活，例如：FMLP、LPS、PG-PS、脂磷酸和某些宿主分子。一旦DC上的TLR识别细菌组分，DC就充当抗原呈递细胞（APC），其是T细胞活化的关键介质。先前的研究表明，T细胞对凋亡的抵抗有助于不适当的T细胞积聚和炎症性肠病（IBD）中慢性粘膜炎症的持续。FasL和肿瘤坏死因子相关凋亡诱导配体（TRAIL）属于TNF超家族的一个亚组，其通过与含有其死亡结构域的受体结合来诱导凋亡。凋亡诱导配体如FasL和TRAIL已被发现在细胞调节中起重要作用。FasL是属于肿瘤坏死因子家族的II型跨膜蛋白，在活化的脾细胞和胸腺细胞中表达，与其参与T细胞介导的应答一致。最近的数据表明，TRAIL也可以诱导各种组织细胞和白细胞的凋亡。该建议的中心假设是，通过DC上FASL和TRAIL的表达介导的诱导活性CD 4 T细胞的凋亡，将对慢性IBD期间发生的特征性炎症具有治疗效果。本发明的具体目的是：1）在体外检测T细胞与作为APC的DC的相互作用; 2）在体外检测由DCs上的FASL和TRAIL表达介导的活性CD 4 T细胞凋亡的作用; 3）确定结肠炎期间DCs中由FASL和TRAIL表达介导的活性CD 4 T细胞凋亡的作用。这些研究将有助于我们理解结肠炎中发生的免疫机制，并有助于我们将来使用体外产生的DC作为恢复肠道免疫的治疗工具。

DESCRIPTION (provided by applicant): Inflammatory bowel diseases (IBD) are chronic relapsing inflammatory conditions; the factors involved in their pathogenesis include the genetic background of patients, the effect of commensal or pathogenic bacteria in the gut, and abnormal activation of innate and adaptive immune responses. Dendritic cells (DCs) appear to play a role in modulating both the innate and adaptive immune response. DCs from the lamina propia of the intestines recognize and respond to bacterial components using pattern recognition receptors, such as Toll-like receptors (TLRs). TLRs sense a distinct repertoire of conserved microbial components, so that collectively, they can detect most microbes. TLRs are activated by specific components of microbes, such as: FMLP, LPS, PG-PS, lipoteicoic acid and certain host molecules. Once TLRs on DCs recognize bacterial components, DCs act as antigen presenting cells (APC), which are critical mediators of T cell activation. Previous studies have shown that T-cell resistance against apoptosis contributes to inappropriate T-cell accumulation and the perpetuation of chronic mucosal inflammation in inflammatory bowel diseases (IBDs). FasL and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) belong to a subgroup of the TNF superfamily which induces apoptosis by binding to their death domain containing receptors. Apoptosis-inducing ligands such as FasL and TRAIL have been found to play an important role in cell regulation. FasL is a type II transmembrane protein that belongs to the tumor necrosis factor family and is expressed in activated splenocytes and thymocytes, consistent with its involvement in T-cell-mediated responses. Recent data indicate that TRAIL may also induce apoptosis in various tissue cells and leukocytes. The central hypothesis of this proposal is that inducing the apoptosis of active CD4 T cells, mediated by the expression of FASL and TRAIL on DCs, will have a therapeutic effect against the characteristic inflammation that occurs during chronic IBD. The specific aims of this proposal are to1) examine in vitro the interaction of T cells with DCs as an APC 2) to examine in vitro the effect of the apoptosis of active CD4 T-cells mediated by the expression of FASL and TRAIL on DCs 3) determine the effect of the apoptosis of active CD4 T-cells mediated by the expression of FASL and TRAIL in DCs during colitis. These studies will contribute to our understanding of the immune mechanisms that occur in colitis and to the possibility of using ex vivo-generated DCs as therapeutic tools for restoring intestinal immunity in the future.