Tissue-specific contribution of Selenoprotein P in colitis and oxidative damage

硒蛋白 P 在结肠炎和氧化损伤中的组织特异性作用

基本信息

批准号：
9269673
负责人：
Sarah Palmer Short
金额：
$ 5.3万
依托单位：
VANDERBILT UNIVERSITY MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-07 至 2019-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9269673
关键词：
Affect Antioxidants Area Azoxymethane Bone Marrow Buffers Carcinoma Cell physiology Cells Coculture Techniques Colitis Colon Colon Carcinoma Colorectal Cancer DNA Damage Development Disease Disease Progression Dysplasia Epidemiologic Studies Epithelial Epithelial Cells Epithelium Generations Genomics Gray unit of radiation dose Homeostasis Hyperplasia Immune In Situ Inflammation Inflammatory Inflammatory Bowel Diseases Injury Intestinal Intraepithelial Neoplasia Intestines Knockout Mice Liver Malignant Neoplasms Mediating Mediator of activation protein Modeling Mus Mutation Myelogenous Myeloid Cells Neoplasms Nutritional Oxidation-Reduction Oxidative Stress Patients Phenotype Play Polyps Population Production Proteins Protocols documentation Role Selenium Selenocysteine Severities Severity of illness Sodium Dextran Sulfate Source Stem cells Supplementation Testing Tissues Trace Elements Variant adduct cancer prevention cancer risk carcinogenesis cell behavior cell injury cell type cytokine cytotoxicity defined contribution in vivo in vivo Model inhibitor/antagonist intestinal epithelium intestinal homeostasis macrophage mouse model oxidant stress oxidative damage public health relevance research study response selenocysteine-tRNA selenoprotein stemness tumor tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): Selenium is a necessary trace element that is incorporated as selenocysteine into selenoproteins, such Selenoprotein P (SEPP1). Several epidemiological studies have inversely correlated nutritional selenium status and cancer risk, particularly in colon cancer. Because SEPP1 is the only selenoprotein to contain more than one selenocysteine, SEPP1 is hypothesized to supply various tissues with selenium to allow in situ generation of selenium containing proteins. However, SEPP1 also contains a redox domain and fulfills a generalized antioxidant function. Such activities suggest that SEPP1 could play a significant role in cancer prevention, and indeed SEPP1 message is downregulated in colorectal cancers. Furthermore, we have found that global SEPP1 reduction increases tumorigenesis in mice placed on a colitis associated carcinoma protocol. But how is SEPP1 mediating these changes in tumor formation? As the majority of SEPP1 is thought to be synthesized in the liver, we previously generated a liver- specific Sepp1 knock-out mouse. Surprisingly, loss of SEPP1 in the liver had no effect on colitis score or tumor formation, suggesting a local source of SEPP1 might modify or influence tumorigenesis. Two possible sources for this locally-derived SEPP1 include 1) intestinal epithelial cells and 2) infiltrating immune cells. Both cell types are known o produce SEPP1, but their separate contributions to inflammatory injury and cancer are yet unknown. Therefore, we will delete SEPP1 in both cell populations individually to define tissue-specific contributions of SEPP1 to inflammatory carcinogenesis. To determine how SEPP1 influences tumor formation, we will utilize a combination of in vivo and ex vivo approaches for both epithelial and myeloid cell populations. Using mouse models of colitis and dysplasia, intestinal enteroid and macrophage/enteroid co-culture, and bone marrow macrophage culture we will determine how tissue-specific SEPP1 affects intestinal homeostasis, intestinal injury, oxidative stress, and macrophage function, and how each function contributes to colitis and associated dysplasia. Interestingly, we have found that Sepp1 loss increases oxidative damage in ex vivo intestinal culture models, and colitis- associated carcinoma is characterized by increased oxidant stress. To specifically investigate the role of oxidative damage and its mechanistic contribution to the SEPP1 phenotype, we will utilize the compound salicylamine, an inhibitor of oxidative adducts, as well as redox-deficient SEPP1 variants. Together, these experiments will elucidate the roles of selenium and SEPP1 in colon disease and disease progression.

描述（由申请人提供）：硒是一种必需的微量元素，以硒代半胱氨酸的形式掺入硒蛋白中，例如硒蛋白 P (SEPP1)。多项流行病学研究表明，营养硒状况与癌症风险呈负相关，尤其是在结肠癌中。 SEPP1 是唯一含有多个硒代半胱氨酸的硒蛋白，SEPP1 被重新捕获，为各种组织提供硒，以允许然而，SEPP1 还含有氧化还原结构域并具有通用的抗氧化剂功能，这表明 SEPP1 在癌症预防中发挥着重要作用，而且 SEPP1 信息确实在结直肠癌中下调。发现整体 SEPP1 减少会增加接受结肠炎相关癌症方案的小鼠的肿瘤发生，但是 SEPP1 是如何介导肿瘤形成的这些变化的呢？我们之前培育了一只肝脏特异性的 Sepp1 敲除小鼠，令人惊讶的是，肝脏中 SEPP1 的缺失对结肠炎评分或肿瘤形成没有影响，这表明 SEPP1 的局部来源可能会改变或影响局部肿瘤的发生。衍生的 SEPP1 包括 1) 肠上皮细胞和 2) 浸润性免疫细胞，这两种细胞类型均已知可产生 SEPP1，但它们对炎症损伤和癌症的单独贡献尚不清楚，因此，我们将删除。两个细胞群中的 SEPP1 分别确定 SEPP1 对炎症癌变的组织特异性贡献为了确定 SEPP1 如何影响肿瘤形成，我们将使用小鼠模型对上皮细胞和骨髓细胞群采用体内和离体方法。结肠炎和发育不良、肠道肠样细胞和巨噬细胞/肠样细胞共培养以及骨髓巨噬细胞培养，我们将确定组织特异性 SEPP1 如何影响肠道稳态、肠道损伤、氧化应激和巨噬细胞功能，以及每种功能如何导致结肠炎和相关的发育不良，我们发现在离体肠道培养模型中Sepp1缺失会增加氧化损伤，并且结肠炎相关癌症的特征是氧化应激增加。为了了解氧化损伤的作用及其对 SEPP1 表型的机制贡献，我们将利用化合物水杨胺（氧化加合物的抑制剂）以及氧化还原缺陷的 SEPP1这些实验将共同阐明硒和 SEPP1 在结肠疾病和疾病进展中的作用。