Evaluating NLR Modulation of Canonical and Non-Canonical NF-kB Signaling in IBD

描述（由申请人提供）：克罗恩病（CD）和溃疡性结肠炎（UC）是炎症性肠病（IBD）的常见表现。这两种使人衰弱的疾病折磨着大约140万美国人和全世界400多万人。我们实验室以前的工作已经从模式识别受体的NLR家族中鉴定出一种新的细胞蛋白亚组，其功能是在IBD期间负调节炎症和肿瘤发展。我们先前已经表明，NLR NLRP 12是临床前小鼠模型中实验性结肠炎和炎症驱动的肿瘤发生的有效调节剂。在IBD期间，NLRP 12通过减弱经典或非经典NF-κB信号传导来调节胃肠道炎症。虽然经典NF-κB信号通路在IBD中的作用已得到充分证实，但非经典NF-κB级联反应的作用相对不明确。我们先前的研究结果表明，一对与非经典NF-κB信号相关的趋化因子在NLRP 12缺失的情况下显著上调，并与小鼠IBD病理生物学增加相关。这些相同的趋化因子在人类IBD患者中也失调。例如，我们的初步数据显示，NLRP 12调节的趋化因子CXCL 13在对英夫利西单抗无反应的CD和UC患者中分别上调42倍和23倍。总之，这些数据说明了NLRP 12和非经典NF-κB信号传导在IBD期间的重要性;然而，潜在的机制仍然没有得到解决。一种假设认为NLRP 12在IBD期间减弱经典NF-κB信号传导;而第二种假设得到我们初步数据的支持，表明NLRP 12抑制非经典NF-κB信号传导级联。通过考虑经典NF-κB通路可以受到非经典NF-κB信号的显著影响，可以调和假设机制中的明显差异。同样，这些途径可能通过细胞类型和/或时间特异性机制进行差异调节，这些机制可以显著影响IBD发病机制。在这里，我提出了一个扩展的研究项目（K 01-DK 092355），以更好地评估这两个流行的假设。该提议的总体目标是产生一组在细胞特异性Cre重组酶破坏后缺乏经典和非经典NF-κB信号传导的小鼠，以更好地表征与IBD的NLRP 12调节相关的机制。IBD期间具有负调控功能的NLR（如NLRP 12）和非经典NF-κB信号转导代表了目前研究不足且未明确定义的领域。拟定研究生成的小鼠品系和数据将作为未来R 01提交的初步数据。在IBD背景下对这些独特途径的评估代表了一个新的方向，将有助于未来发现与肠道免疫系统稳态相关的新发现，并导致针对这些疾病的新治疗策略。

DESCRIPTION (provided by applicant): Crohn's disease (CD) and ulcerative colitis (UC) are common manifestations of inflammatory bowel disease (IBD). These two debilitating disorders afflict approximately 1.4 million Americans and over 4 million people worldwide. Previous work from our lab has identified a novel sub-group of cellular proteins from the NLR family of pattern recognition receptors that function to negatively regulate inflammation and tumor development during IBD. We have previously shown that the NLR NLRP12 is a potent modulator of experimental colitis and inflammation driven tumorigenesis in pre-clinical mouse models. During IBD, NLRP12 modulates gastrointestinal inflammation through the attenuation of either canonical or non-canoincal NF-κB signaling. While the role of the canonical NF-κB signaling pathway during IBD is well established, the contribution of the non-canonical NF-κB cascade is relatively uncharacterized. Our previous findings indicate that a pair of chemokines associated with non-canonical NF-κB signaling is significantly up-regulated in the absence of NLRP12 and associated with increased IBD pathobiology in mice. These same chemokines are also dysregulated in human IBD patients. For example, our preliminary data revealed that the NLRP12 regulated chemokine CXCL13 is up-regulated 42- and 23-fold in CD and UC patients that are unresponsive to infliximab, respectively. Together, these data illustrate the importance of NLRP12 and non-canonical NF-κB signaling during IBD; however, the underlying mechanism/s is still unresolved. One hypothesis suggests that NLRP12 attenuates canonical NF-κB signaling during IBD; whereas, a second hypothesis that is supported by our preliminary data, indicates that NLRP12 inhibits the non-canoncial NF-κB signaling cascade. The apparent discrepancies in the hypothesized mechanisms can be reconciled by considering that the canonical NF-κB pathway can be significantly influenced by noncanoncial NF-κB signaling. Likewise, it is possible that these pathways are differentially modulated through cell type and/or temporal specific mechanisms that can significantly impact IBD pathogenesis. Here, I propose an extension to research project (K01-DK092355) to better evaluate these two prevailing hypotheses. The overall goal of this proposal is to generate a panel of mice that are deficient in canonical and non-canonical NF-κB signaling following cell specific Cre-recombinase disruption to better characterize the mechanism associated with NLRP12 modulation of IBD. NLRs with negative regulatory functions, such as NLRP12, and non-canonical NF-κB signaling during IBD represent areas that are currently understudied and not well defined. The mouse lines and data generated by the proposed studies will serve as preliminary data for a future R01 submission. The evaluation of these unique pathways in the context of IBD represent a novel direction that will contribute to future discoveries associated with immune system homeostasis in the gut and lead to new therapeutic strategies targeting these diseases.