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: 8690770
• 负责人: Keith T. Wilson
• 金额: $ 37.83万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8690770
• 关键词: Affect; American; Amino Acids; Animals; Apoptosis; Arginine; Award; Azoxymethane; Bone Marrow; Carcinoma; Cationic Amino Acid Transporter 2; Cell Line; Cell physiology; Chimera organism; Citrulline; Clinical; Colitis; Colon; Colon Carcinoma; Colonic Neoplasms; Complementary and alternative medicine; Crohn' s disease; DNA Damage; Defect; Development; Disease; Disease remission; Down-Regulation; Dysplasia; Enzymes; Epithelial; Epithelial Cells; Exhibits; Funding; Gene Expression; Histology; Human; Immune response; Immunotherapy; In Vitro; Inflammation; Inflammatory Bowel Diseases; Injury; Intervention; Investigation; Lymphocyte; Macronutrients Nutrition; Maintenance; Malignant Neoplasms; Metabolism; Modeling; Morbidity - disease rate; Mus; Myelogenous; NOS2A gene; National Center for Complementary and Alternative Medicine; Natural Immunity; Nitric Oxide; Oral; Ornithine; Ornithine Decarboxylase; Ornithine-oxo-acid aminotransferase; Pathway interactions; Patients; Permeability; Phenotype; Polyamines; Process; Production; Proline; Protein Biosynthesis; Regulatory T-Lymphocyte; Reporting; Risk; Role; Sodium Dextran Sulfate; Source; Splenocyte; Supplementation; Tissues; Tumor Tissue; Ulcerative Colitis; Work; Wound Healing; adaptive immunity; arginase; base; cytokine; disorder prevention; human NOS2A protein; human study; immune function; improved; inhibitor/antagonist; injury and repair; innate immune function; macrophage; migration; prevent; public health relevance; response; semi essential amino acid; treatment strategy; tumor; tumorigenesis; uptake

DESCRIPTION (provided by applicant): Inflammatory bowel disease (IBD), consisting of ulcerative colitis (UC) and Crohn's disease, is a source of substantial morbidity for 1.4 million people affected in the USA, and it can progress to colon cancer. It is difficult to treat, with cosly immunotherapies only inducing remission in less than half of cases. We have been focusing on the role of the semi-essential amino acid, L-arginine (L-Arg) as a complementary and alternative medicine. We have demonstrated mechanisms for beneficial effects of L-Arg in vitro and in colitis. Cationic amino acid transporter 2 (CAT2), the inducible transporter of L-Arg, and uptake of L-Arg are upregulated in murine colitis, and oral L-Arg supplementation is effective as a treatment for epithelial injury and inflammation induced by dextran sulfate sodium (DSS), a model that mimics UC. CAT2 expression, L-Arg uptake, and L-Arg levels are all decreased in UC tissues. CAT2-/- mice exhibit marked exacerbation of DSS colitis, and colon tumorigenesis in the azoxymethane (AOM)-DSS model of colitis-associated carcinoma (CAC). CAT2-/- mice do not respond to L-Arg supplementation in the DSS colitis model, suggesting that L-Arg alone as a therapy for human UC may not be sufficient to overcome its impaired transport into tissues. Colonic epithelial restitution in a wound repair model is dependent on CAT2 and this is due to utilization of L-Arg by arginase that generates L-ornithine (L-Orn), which can be metabolized by either ornithine decarboxylase (ODC) to generate polyamines, or ornithine aminotransferase (OAT) to generate L-proline (L-Pro). While inhibition of arginase or knockdown of arginase 1 (Arg1) prevented restitution, this could be completely restored, in the presence of L- Arg, when either L-Orn or L-Pro was added. Knockdown of OAT, but not ODC, prevented beneficial effects of L-Arg on restitution, implicating OAT in the maintenance of epithelial function. Additionally, ODC+/- mice exhibit improvement in DSS colitis, with increased tissue macrophage NO production, and enhanced regulatory T cell and macrophage responses, indicating a deleterious role for polyamines in this model. We hypothesize that benefits of L-Arg in colitis and colitis-associated tumorigenesis depend on CAT2 and downstream effectors to improve epithelial restitution, innate immune function, and adaptive immunity. In our Specific Aims we will determine if: 1) exacerbation of DSS colitis due to deletion of CAT2 and loss of L-Arg availability that mimics human UC is due to an epithelial or macrophage defect and if this is ameliorated by supplementation of L-Orn or L-Pro in combination with L-Arg; 2.) improvement in DSS colitis in ODC+/- mice is due to an epithelial or macrophage effect and if it results from enhanced L-Arg availability for iNOS and/or OAT; 3.) accelerated tumorigenesis with CAT2 deletion is due to an epithelial or macrophage defect and if this process can be beneficially modulated by downregulation of ODC or supplementation of L-Orn or L-Pro in combination with L- Arg. Through investigation of epithelial and immune function, these studies seek to provide new macronutrient- based strategies for treatment of IBD and prevention of colitis-associated dysplasia and carcinoma.

描述（由申请人提供）：由溃疡性结肠炎（UC）和克罗恩病组成的炎症性肠病（IBD）是美国140万人的大量发病来源，它可以发展为结肠癌。很难治疗，只有不到一半的情况就可以诱导免疫疗法来诱导缓解。我们一直专注于半必需的氨基酸L-精氨酸（L-ARG）作为补充和替代药物的作用。我们已经证明了L-ARG体外和结肠炎的有益作用的机制。阳离子氨基酸转运蛋白2（CAT2），L-ARG的可诱导转运蛋白和L-ARG的摄取在鼠结肠炎中上调，口服L-ARG补充是有效的，可以治疗dextran硫酸盐（DSS）诱导的上皮损伤和炎症（DSS）（DSS），一种模型，该模型是Mimics UC。 UC组织中CAT2表达，L-ARG摄取和L-ARG水平均降低。 CAT2 - / - 小鼠表现出明显的DSS结肠炎和偶氮甲烷（AOM）-DSS模型的结肠肿瘤发生的明显加重。 CAT2 - / - 小鼠对DSS结肠炎模型中的L-ARG补充无反应，这表明单独使用L-Arg作为人类UC的疗法可能不足以克服其运输受损到组织的运输。伤口修复模型中的结肠上皮恢复依赖于CAT2，这是由于精氨酸酶利用L-Arg，生成L-雌激酶（L-orn）（L-orn），可以通过任何一种鸟氨酸脱羧酶（ODC）代谢来代谢，以生成多胺氨基氨酸或鸟氨酸氨基氨基植物（Ornithine aminotrans）（Oatrane（Oat）l-Proine（Oatate）l-Proce l-Proline（l-Prodrane）。虽然抑制精氨酸酶或精氨酸酶1（ARG1）阻止恢复原状，但在添加L-orn或L-Pro时，可以完全恢复这一点。击倒燕麦而不是ODC阻止了L-Arg对恢复原状的有益影响，这意味着燕麦在维持上皮功能方面。此外，ODC +/-小鼠在DSS结肠炎中表现出改善，组织巨噬细胞没有产生，并增强了调节性T细胞和巨噬细胞反应，这表明多胺在该模型中对多胺具有有害作用。我们假设L-ARG在结肠炎和与结肠炎相关的肿瘤发生中的益处取决于CAT2和下游效应子，以改善上皮恢复，先天免疫功能和适应性免疫。在我们的具体目的中，我们将确定是否：1）由于删除Cat2和L-Arg的可用性而导致DSS结肠炎加剧 该模拟人类UC是由于上皮或巨噬细胞缺陷引起的，如果通过补充L-orn或L-Pro与L-Arg的补充来改善； 2.）ODC +/-小鼠中DSS结肠炎的改善是由于上皮或巨噬细胞效应引起的，如果它是由INOS和/或燕麦的L-ARG供应增强而引起的； 3.）用CAT2缺失加速的肿瘤发生是由于上皮或巨噬细胞缺陷引起的，如果可以通过下调ODC或补充L-orn或L-Pro与L-arg结合使用该过程来调节此过程。通过研究上皮和免疫功能，这些研究试图提供新的基于大型营养素的策略来治疗IBD，并预防与结肠炎相关的发育不良和癌。