Immunomodulatory effects of arginine supplementation in colitis and colon cancer

补充精氨酸对结肠炎和结肠癌的免疫调节作用

• 批准号: 7895707
• 负责人: Keith T. Wilson
• 金额: $ 37.67万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-15 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7895707
• 关键词: Acute; Address; Adverse effects; Affect; American; Amino Acids; Apoptosis; Arginine; Attenuated; Azoxymethane; Basic Amino Acid Transport Systems; Biological; Body Weight decreased; Carrier Proteins; Cell physiology; Cells; Chronic; Citrobacter rodentium; Clinical; Colitis; Colon; Colon Carcinoma; Colonic Neoplasms; Crohn' s disease; Data; Disease; Effectiveness; Environment; Epithelial; Epithelial Cells; Equilibrium; Frequencies; Generations; Histology; Human; Immune response; Immunity; Immunobiology; Immunology; In Vitro; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Inflammatory disease of the intestine; Lead; Lymphocyte; Malignant Neoplasms; Metabolic Pathway; Metabolism; Microbe; Modeling; Morbidity - disease rate; Mucositis; Mus; Nitric Oxide; Nitric Oxide Synthase; Ornithine; Ornithine Decarboxylase; Outcome; Pathway interactions; Patients; Phagocytosis; Polyamines; Population; Prevention; Process; Protein Family; Proteins; Public Health; Regulation; Regulatory T-Lymphocyte; Reporting; Research Design; Rest; Risk; Role; Route; Serum; Sodium Dextran Sulfate; Source; Stimulus; Stress; Supplementation; System; Testing; Tissues; Translations; Ulcerative Colitis; Weight; Wild Type Mouse; Work; Wound Healing; arginase; arginine treatment; carcinogenesis; chemokine; colitis associated cancer; colon carcinogenesis; cost; cytokine; enzyme substrate; extracellular; human NOS2A protein; immune activation; immunoregulation; improved; in vivo; in vivo Model; insight; macrophage; mouse model; novel strategies; response; semi essential amino acid; therapy development; translational study; tumor; uptake

DESCRIPTION (provided by applicant): Inflammatory bowel disease (IBD), consisting of ulcerative colitis (UC) and Crohn's disease (CD), is a source of extensive morbidity and risk for progression to colon cancer in the US population, with more than one million Americans affected. The semi-essential amino acid L-arginine (L-Arg) has been touted as a supplement with many potential benefits including enhancement of immunity. In response to RFA AT-07-004 we will conduct mechanistic studies in mouse models to address the potential value of L-Arg as a supplement in IBD and determine if it can reduce risk for colitis-associated cancer. During conditions of immune activation, the two major routes for L-Arg utilization are the inducible nitric oxide (NO) synthase (iNOS) and arginase pathways. Arginase generates L-ornithine, the substrate for the enzyme ornithine decarboxylase (ODC) that produces polyamines, which have been shown to enhance wound repair and have been implicated as regulatory factors in immune responses. Our data in two murine models of colitis indicate that supplementation of mice with L-Arg or deletion of iNOS improves colitis, while inhibition of arginase or ODC exacerbates disease. L-Arg uptake into cells is primarily dependent on the cationic amino acid transporter (CAT) proteins, particularly CAT2, which is the predominant transporter in macrophages and CAT1, which is ubiquitously expressed. We will show preliminary data that L-Arg availability is important in cellular functions such as global protein translation, wound repair, and responses to inflammatory stimuli. We will also show that CAT2 expression is upregulated in colitis tissues and colitis-associated tumors, and that mice deficient in CAT2 appear to have exacerbation of colitis. Our hypothesis is that L-Arg availability is an important regulator of mucosal inflammation in IBD such that the amount of L-Arg in the extracellular environment, the transport of L- Arg from outside to inside cells, and the balance of competing metabolic pathways for the utilization of L-Arg are all important in immunomodulation. Our specific aims are to determine the biological effects of L-Arg supplementation and the role of its uptake and metabolism in models in which we will study: 1.) In vitro: A.) epithelial integrity; and B.) macrophage function; 2.) In vivo colitis: A.) clinical parameters; B.) tissue iNOS and polyamine levels, and serum NO and L-Arg levels; C.) biological effects on colonic epithelial cells and macrophages, D.) responses in colonic lymphocytes; 3.) In vivo colitis-associated cancer: A.) clinical parameters; and B.) tumor CAT1, CAT2, iNOS, cytokine, and polyamine levels, and serum NO and L-Arg levels. In these studies, we seek to establish new insights into the role of L-Arg in mucosal immunology and to provide evidence for the potential beneficial effects of L-Arg supplementation in both IBD and IBD-associated cancer while establishing the importance of L-Arg uptake in this process. This work is expected to provide the groundwork for translational studies in patients that could lead to new adjunctive therapies that would be safe, effective, and low in cost and improve the long-term outcome in IBD. PUBLIC HEALTH REVELANCE: Inflammatory bowel disease (IBD) affects more than one million Americans and results in a substantial amount of suffering and the risk for developing cancer of the colon. In this project we will test the hypothesis that supplementation of the amino acid L-arginine (L-Arg) is beneficial in these diseases and that L-Arg uptake into cells has an essential role in the modulation of intestinal inflammation. We will use in vitro and in vivo models of colitis and colitis-associated cancer to conduct mechanistic studies that are designed to generate new insights into the immunobiology of IBD and lay the groundwork for new approaches to attenuate inflammation and associated carcinogenesis.

描述（由申请人提供）：由溃疡性结肠炎（UC）和克罗恩病（CD）组成的炎症性肠病（IBD），是美国人群中广泛发病率和进展为结肠癌的风险的来源，患有超过一百万美国人的影响。半必需的氨基酸L-精氨酸（L-ARG）已被吹捧为具有许多潜在益处，包括增强免疫力。为了响应RFA AT-07-004，我们将在小鼠模型中进行机械研究，以解决L-ARG作为IBD中补充剂的潜在价值，并确定它是否可以降低与结肠炎相关癌症的风险。在免疫激活的条件下，L-ARG利用的两种主要途径是诱导型一氧化氮（NO）合酶（INOS）和精氨酸酶途径。精氨酸酶产生L-雌激酶，这是产生多胺的酶鸟氨酸脱羧酶（ODC）的底物，已显示出可增强伤口修复的多胺，并被视为免疫反应中的调节因子。我们在两个鼠类结肠炎模型中的数据表明，补充L-ARG或iNOS缺失的小鼠可改善结肠炎，而精氨酸酶或ODC恶化疾病的抑制作用。 L-Arg摄取细胞的摄取主要取决于阳离子氨基酸转运蛋白（CAT）蛋白，尤其是CAT2，cat2是巨噬细胞和CAT1中主要的转运蛋白，这是普遍表达的。我们将表明初步数据表明，L-Arg的可用性在细胞功能中很重要，例如全球蛋白质翻译，伤口修复和对炎症刺激的反应。我们还将证明CAT2表达在结肠炎组织和结肠炎相关的肿瘤中被上调，并且缺乏CAT2的小鼠似乎会加剧结肠炎。我们的假设是，L-Arg的可用性是IBD中粘膜炎症的重要调节剂，因此L-ARG在细胞外环境中的数量，L-arg从外部到外部细胞的运输以及L-ARG利用的竞争代谢途径的平衡在于免疫调节。我们的具体目的是确定补充L-ARG的生物学作用及其在我们将研究的模型中的摄取和代谢的作用：1。）体外：A。A.）上皮完整性；和B.）巨噬细胞功能； 2.）体内结肠炎：A。）临床参数； B.）组织iNOS和多胺水平，以及血清NO和L-ARG水平； C.）生物学对结肠上皮细胞和巨噬细胞的作用，D。）结肠淋巴细胞的反应； 3.）体内结肠炎相关的癌症：A。）临床参数；和B.）肿瘤CAT1，CAT2，INOS，细胞因子和多胺水平以及血清NO和L-ARG水平。在这些研究中，我们试图对L-ARG在粘膜免疫学中的作用建立新的见解，并为在IBD和IBD相关的癌症中提供L-ARG补充的潜在有益作用的证据，同时确立L-Arg摄取在此过程中的重要性。预计这项工作将为患者的转化研究提供基础，这可能会导致新的辅助疗法，这些辅助疗法将是安全，有效且成本较低并改善IBD的长期结果。 公共卫生的启示：炎症性肠病（IBD）影响了一百万的美国人，并导致大量的痛苦和患结肠癌癌的风险。在该项目中，我们将测试以下假设：补充氨基酸L-精氨酸（L-ARG）在这些疾病中是有益的，并且L-Arg摄取细胞对细胞具有至关重要的作用在肠道炎症的调节中至关重要。我们将使用体外和体内结肠炎和与结肠炎相关的癌症进行机械研究，旨在为IBD的免疫生物学产生新的见解，并为减轻炎症和相关的癌变的新方法奠定了基础。