Vitamin D and the Immune System

描述（由申请人提供）：我们的初步结果显示125 (OH)2D3直接抑制IL-17，以及125 (OH)2D3逆转瘫痪和抑制EAE[多发性硬化症（MS）小鼠模型]的进展，这与抑制IL-17有关。我们建议研究其中的机制。我们假设，了解所涉及的机制将为我们理解维生素D内分泌系统和免疫系统之间的相互作用带来新的概念，这可能为控制MS和其他TH17依赖性炎症性疾病（包括炎症诱导的骨质流失）提供治疗靶点。在Specific Aim 1中，我们将检验1,25(OH)2D3在EAE小鼠体内治疗对IL-17和其他细胞因子产生的影响（将从EAE小鼠中分离出脑和脊髓以及脾细胞和淋巴结），以及1,25(OH)2D3对各种细胞因子产生的影响，包括TH17细胞（IL-17A, IL-17F, IL-21, IL-22）， TH2细胞（IL-4, IL-5），调节性T细胞（IL-10和TGF?）和先天免疫细胞(IL-23, IL-12，评估il - 6和抗炎细胞因子IL-27。在初步结果中，我们首次注意到1,25(OH)2D3对活化的IL-17表达和转录具有直接抑制作用。我们将研究其中的机制（1,25(OH)2D3可能通过抑制NFAT、Runx1和ROR γ转录因子介导的激活来介导这种抑制）。用ChIP-seq方法对EAE小鼠CD4+T细胞DNA中NFAT、Runx1和维生素D受体（VDR）结合位点进行全基因组分析。这些研究将使我们能够识别新的靶基因，并评估参与免疫功能的基因之间的功能关系如何在1,25(OH)2D3治疗后发生改变。这些研究将提供125 (OH)2D3逆转瘫痪的机制。我们确定的机制可能反映了1,25(OH)2D3在控制病理性免疫反应中的治疗作用的更一般的机制。在Specific Aim 2中，由于临床研究正在用高剂量维生素D治疗MS患者，我们也建议研究高剂量膳食维生素D对瘫痪、EAE进展以及IL-17和其他细胞因子产生的影响。这些研究提供了一个独特的机会，将斯坦曼实验室在多发性硬化症和免疫学方面的专业知识与克里斯塔科斯实验室在维生素D方面的专业知识结合起来，增加我们对维生素D内分泌系统和免疫系统之间相互作用的理解。这些研究结果可能为MS和其他TH17依赖性炎症疾病提供新的治疗靶点和治疗策略。该申请适用于R21机制，该机制支持“涉及相当大的风险，但可能导致在特定领域取得突破，可能对生物医学或临床研究领域产生重大影响”的项目。

DESCRIPTION (provided by applicant): Our preliminary results have shown a direct suppression of IL-17 by 1,25(OH)2D3 as well as reversal of paralysis and inhibition of progression of EAE [a murine model of multiple sclerosis (MS)] by 1,25(OH)2D3 which is associated with an inhibition of IL-17. We propose to examine the mechanisms involved. We hypothesize that understanding the mechanisms involved will result in new concepts in our understanding of the interaction between the vitamin D endocrine system and the immune system that may suggest therapeutic targets for the control of MS and other TH17 dependent inflammatory diseases including inflammation induced bone loss. In Specific Aim 1 we will examine the effect of in vivo treatment of EAE mice with 1,25(OH)2D3 on the production of IL-17 and other cytokines (brains and spinal cords as well as splenocytes and lymph nodes will be isolated from EAE mice and the effect of 1,25(OH)2D3 on the production of various cytokines including those produced by TH17 cells (IL-17A, IL-17F, IL-21, IL-22), TH2 cells (IL-4, IL-5), regulatory T cells (IL-10 and TGF?) and innate immune cells (IL-23, IL-12, IL6 and the anti-inflammatory cytokine, IL-27) will be assessed. In preliminary results we noted for the first time that 1,25(OH)2D3 has a direct inhibitory effect on activated IL-17 expression and transcription. The mechanisms involved will be examined (1,25(OH)2D3 may mediate this repression by inhibiting activation mediated by NFAT, Runx1 and ROR gamma transcription factors). Genome-wide analysis of NFAT, Runx1 and vitamin D receptor (VDR) binding sites in CD4+T cell DNA isolated from EAE mice treated with vehicle or 1,25(OH)2D3 using ChIP-seq will also be done. These studies will enable us to identify new target genes and to assess how functional relationship among genes involved in immune function may be altered after 1,25(OH)2D3 treatment. These studies would provide mechanisms for the reversal of paralysis by 1,25(OH)2D3. It is possible that the mechanisms we identify may reflect more general mechanisms involved in a therapeutic role of 1,25(OH)2D3 in the control of pathological immune responses. In Specific Aim 2, since clinical studies are being done treating MS patients with high dose vitamin D, we also propose to examine the effect of high dose dietary vitamin D on paralysis, on the progression of EAE and the production of IL-17 and other cytokines. These studies provide a unique opportunity to combine the expertise of the Steinman lab in multiple sclerosis and immunology and the Christakos lab in vitamin D to increase our understanding of the interaction between the vitamin D endocrine system and the immune system. Findings from these studies may suggest new therapeutic targets and treatment strategies for MS and other TH17 dependent inflammatory diseases. This application is appropriate for the R21 mechanism which supports projects that "involve considerable risk but may lead to a breakthrough in a particular area that could have a major impact on a field of biomedical or clinical research." PUBLIC HEALTH RELEVANCE: An increased understanding of the interaction between the vitamin D endocrine system and the immune system, with a focus on IL-17, a central player in the mammalian immune system, may suggest possible therapeutic targets and treatment strategies for the control of MS and other TH17 dependent inflammatory diseases, including inflammation induced bone loss.