Study of Reg Receptor-Ligand Biology in the GI Mucosa

描述（由申请人提供）：炎症性肠病（IBD）是一种 以持续的粘膜损伤和再生为特征的疾病。我们将mRNA 通过基因芯片杂交和高通量文库进行转录谱分析 测序以鉴定胃肠道中的新的或未知的基因 粘膜可能介导保护或再生程序。我们 结果已经确定REG基因家族的成员是最高的 诱导的mRNAs在IBD粘膜，这表明他们可能发挥重要作用， 在粘膜修复中。虽然这个基因家族的生物学功能仍然存在， 尽管我们对此知之甚少，但最近的研究表明，REG蛋白可能作为 组织分裂原。我们已经鉴定并纯化了一种新的REG细胞表面 与Reg I-α结合的受体（REG-R）。重组Reg治疗 I-α导致ERK MAP激酶的快速和剂量依赖性激活 通路REG-R受体是一种跨膜蛋白， 小的胞质结构域，缺乏受体所需的结构特征 与下游信号传导通路偶联。因此，我们还确定了 与REG-R共纯化的第二种蛋白质。我们的三部分假设是：（1） REG基因家族的所有成员结合并激活该细胞表面 受体，（2）活性受体复合物含有REG-R和另外的 具有信号传导所需的细胞质决定簇的亚基 转导，和（3）单个REG蛋白及其同源受体 复合物构成了一个新的受体-配体系统，具有独特的重要性 维持和修复胃肠道粘膜。我们建议使用新的 开发了工具，直接测试这一假设在三个具体目标：（1） 确定单个REG基因之间是否存在差异， 结合并激活受体介导的信号转导。表征 表达REG-R的粘膜群体与表达REG-R的粘膜群体之间的空间关系 REG基因产物在正常和病变胃肠道粘膜中的定位; (2)表征REG-R复合物的其他组分并阐明 配体介导的受体信号传导的结构要求;和（3） 研究REG-R-配体系统在体外和体内作为 这是开发鼠REG-R功能丧失模型的前奏。这包括 实验以检查该受体配体所起的功能作用 系统在体外和体内病理模型下与异位或异位妊娠相关， 增加REG蛋白的表达。这些研究将提供重要的新 了解调节粘膜再生程序的因素，并可能导致 新的方法来治疗影响胃肠道粘膜的疾病， 炎症性肠病

DESCRIPTION (provided by applicant): Inflammatory bowel disease (IBD) is a disease marked by ongoing mucosal injury and regeneration. We have applied mRNA transcript profiling by GeneChip hybridization and high-throughput library sequencing to identify novel or unsuspected genes in the gastrointestinal mucosa that potentially mediate protective or regenerative programs. Our results have identified members of the REG gene family as among the most highly induced mRNAs in IBD mucosa, suggesting that they may serve an important role in mucosal repair. While the biological function for this gene family remains poorly understood, recent work has suggested that REG proteins may serve as tissue mitogens. We have identified and purified a novel REG cell surface receptor (REG-R) that binds to Reg I-alpha. Treatment with recombinant Reg I-alpha resulted in rapid and dose-dependent activation of the ERK MAP kinase pathway. The REG-R receptor is a transmembrane protein that contains only a small cytoplasmic domain and lacks structural features required for receptor coupling to downstream signaling pathways. Accordingly, we have also identified a second protein that co-purifies with REG-R. Our three part hypothesis is: (1) all members of the REG gene family bind and activate this cell surface receptor, (2) the active receptor complex contains the REG-R and an additional subunit possessing the cytoplasmic determinants required for signal transduction, and (3) individual REG proteins and their cognate receptor complex constitute a new receptor-ligand system with unique importance to the maintenance and repair of the gastrointestinal mucosa. We propose to use newly developed tools to directly test this hypothesis in three specific aims: (1) determine if differences exist between individual REG genes in their ability to bind and activate receptor-mediated signal transduction. Characterize the spatial relationship between mucosal populations expressing the REG-R and the location of REG gene products in normal and diseased gastrointestinal mucosa; (2) Characterize additional components of the REG-R complex and elucidate the structural requirements of ligand-mediated receptor signaling; and (3) Investigate the role for the REG-R-ligand system in vitro and in vivo as a prelude to developing a murine REG-R loss-of-function model. This includes experiments to examine the functional role served by this receptor ligand system in vitro and under in vivo pathologic models associated with ectopic or increased expression of REG proteins. These studies will provide important new insights into factors that regulate mucosal regenerative programs and may lead to new ways to treat diseases affecting the gastrointestinal mucosa like inflammatory bowel disease.