Dendritic Cell Specific Role of the Inhibitory Lyn Kinase in the Pathogenesis of Inflammatory Bowel Disease

 描述(申请人提供)：炎症性肠病(IBD)是一种不治之症，确定新的治疗靶点是高度优先的。根据 美国疾病控制与预防中心表示，美国有100-130万IBD病例，预计未来这种疾病的患病率还会上升。在IBD患者群体中，大约一半的患者被诊断为克罗恩病，另一半被诊断为溃疡性结肠炎。目前治疗IBD的药物包括抗炎药物，这些药物既昂贵又往往无效。为了改进我们目前的IBD治疗方案，我们必须通过阐明具体的细胞机制和相关途径来加深我们对该病生物学的理解。对IBD生物学理解的最新进展之一是Lyn激酶与结肠炎发展之间的联系。通过使用DSS小鼠结肠炎模型，研究人员证明了在结肠炎发展过程中，系统Lyn激酶活性对宿主有利，但细胞特异性参与尚不清楚。由于我们最近发表了树突状细胞特异性的Lyn激酶对Lyn-/-小鼠的全身性炎症效应负责，我们假设DC对Lyn-/-小鼠结肠炎的易感性增加有专门的责任。我们建议通过比较IL-10KO和DSS结肠炎模型中DC特异性LYN-/-、MΦ特异性LYN-/-和LYN-/-(全身性)小鼠中LYN的发展和进展来阐明LYN的细胞特异性作用。我们也有证据表明，Lyn是通过Syk-PKCδ-CARD9途径调节TLR2信号的，这使我们假设Lyn是DC表面其他TLR信号和细胞因子产生的调节者。我们建议1)阐明LYN在引导其他表面TLR信号转导中的作用，2)研究LYN如何通过Syk-PKCδ-CARD9途径影响DC中其他细胞因子和趋化因子的产生，3)研究LYN如何影响DC对肠道病原体的免疫反应。最后，我们有初步的数据表明，Lyn-Syk-PKCδ-CARD9通路对DC高分泌肿瘤坏死因子α有重要作用，因此我们假设，通过遗传或药物操作Lyn-Syk-PKCδ-CARD9通路可以通过降低肿瘤坏死因子α的产生来缓解结肠炎。我们建议1)将IL-10KO和DSS诱导的LYN-/-小鼠与PKCδ-/-和CARD9-/-小鼠杂交，以减少这些动物引起的结肠炎；2)通过用MLR-1023(LYN激活剂)靶向LYN激酶来预防或治疗IL-10KO小鼠或DSS治疗WT小鼠的结肠炎。所有建议的实验都是为了增加我们对Lyn激酶在IBD发病机制中DC特异性作用的理解，并扩大我们对Lyn激酶信号转导和生物学的全面了解。我们最终希望我们的研究能够产生针对Lyn-Syk-PKCδ-CARD9通路的治疗剂，用于临床治疗IBD。

 DESCRIPTION (provided by applicant): Inflammatory Bowel disease (IBD) is an incurable disease, for which identification of novel therapeutic targets is a high priority. According to the CDC, there are 1-1.3 million cases of IBD in the United States and the prevalence of this disease is expected to rise in the future. Within the IBD patient population, about half of the patients were diagnosed with Crohn's Disease and the other half diagnosed with Ulcerative Colitis. The current treatments for IBD consist of anti-inflammatory drugs which are both expensive and often ineffective. In order to improve upon our current repertoire of treatments for IBD, we must further our understanding of the biology of the disease by elucidating the specific cellular mechanisms and pathways involved. One of the most recent additions to the understanding of the biology of IBD was the connection between Lyn kinase and colitis development. By using a DSS mouse model of colitis, researchers demonstrated that systemic Lyn kinase activity is beneficial to the host during colitis development, but the cell specific involvement was not elucidated. Since we recently published that Lyn kinase-specifically in DCs is responsible for the systemic inflammatory effect in lyn-/- mice, we hypothesize that DCs are specifically responsible for the enhanced susceptibility to the colitis in lyn-/- mice. We propose o elucidate the cell-specific role of Lyn by comparing colitis development and progression in DC-specific lyn-/- versus MΦ-specific lyn-/- versus lyn-/- (systemic) mice in both the IL-10KO and DSS colitis models. We also have evidence showing that Lyn is a regulator of TLR2 signaling via the Syk- PKCδ-Card9 pathway leading us to hypothesize that Lyn is a regulator of other surface TLR signaling and cytokine production in DCs. We propose to 1) elucidate Lyn's role in directing other surface TLR signaling, 2) investigate how Lyn affects other cytokine and chemokine production via the Syk-PKCδ-Card9 pathway in DCs, and 3) study how Lyn affects the immune response to intestinal pathogens in DCs. Finally, we have preliminary data demonstrating that the Lyn-Syk-PKCδ-CARD9 pathway contributes significantly to hyper- production of TNFα in DCs, therefore we hypothesize that genetic or pharmacological manipulation of the Lyn- Syk-PKCδ-CARD9 pathway can be used to ameliorate colitis by lowering TNFα production. We propose to 1) reduce IL-10KO and DSS induced colitis in lyn-/- mice by crossing these animals to pkcδ-/- and card9-/- mice, 2) prevent or treat colitis in IL-10KO mice or DSS treated wt mice by targeting Lyn kinase with MLR-1023 (Lyn activator). All of the proposed experiments are designed to increase our understanding of the DC-specific role of Lyn kinase in IBD pathogenesis and to expand our overall knowledge of Lyn kinase signaling and biology. We ultimately desire to have our research lead to the generation of therapeutic agents targeting the Lyn-Syk- PKCδ-Card9 pathway for IBD treatment in the clinic.