IL-2 Suppression by Endocannabinoid Activation of PPARgamma

描述(申请人提供)：这项五年研究计划的总体目标是阐明与结构相关的内源性大麻素、花生胺(AEA)和2-花生四烯基甘油(2-AG)调节T细胞功能和白介素2(IL-2)调节的分子机制。目前，内源性大麻素系统的目的论作用尚不清楚，但越来越多的证据表明，它可能对维持免疫稳态有重要贡献。大量研究表明，AEA和2-AG对生物系统有深远的影响，免疫系统是其中最广泛的特征之一。目前提出的研究的意义在于，它们将为内源性大麻素调节T细胞功能，特别是IL-2调节的分子机制提供直接的机制洞察。新的初步结果表明，AEA和2-AG对IL-2的抑制依赖于COX-2代谢，导致核受体PPARGamma的激活，而不依赖于CB1和CB2。其他结果表明，特定的机制涉及PPARγ激活破坏激活的T细胞核因子(NFAT)。基于上述观察和提案中提出的其他初步数据，我们目前的研究将检验这一假设：内源性大麻素AEA和2-AG对IL-2的抑制是通过两种不同的大麻素受体非依赖性机制破坏NFAT调节而介导的：(A)改变细胞内钙调节；(B)在COX-2介导的AEA和2-AG转化为PPARGamma激动剂后激活PPARGamma。我们将使用以下特定目标(SA)来验证我们的假设：SA1是表征AEA和2-AG改变细胞内钙调节的作用，AEA和2-AG在解除对NFAT的调控从而抑制IL-2基因表达方面起作用；SA2是表征COX-2在AEA和2-AG解除对NFAT的调控和抑制IL-2的作用中的作用；SA3是表征AEA和2-AG处理对PPARγ的激活在改变NFAT调节和抑制IL-2中的作用；和SA4的目的是鉴定和鉴定AEA和2-AG的生物活性形式，并阐明其在IL-2抑制中的作用。

DESCRIPTION (provided by applicant): The overall goal of this 5 year research plan is to elucidate the molecular mechanism responsible for the modulation of T cell function and interleukin-2 (IL-2) deregulation by the structurally-related endocannabinoids, anandamide (AEA) and 2-arachidonyl glycerol (2-AG). Presently, the teleological role of the endocannabinoid system is unknown but there is a growing body of evidence suggesting that it may significantly contribute to the maintenance of immunologic homeostasis. Numerous studies have demonstrated profound effects on biological systems by AEA and 2-AG, with the immune system representing one of the most extensively characterized. The significance of the current proposed studies is that they will provide direct mechanistic insight into the molecular mechanism by which endocannabinoids modulate T cell function, specifically IL-2 regulation. Novel preliminary results are presented demonstrating that IL-2 suppression by both AEA and 2-AG are dependent on COX-2 metabolism leading to the activation of the nuclear receptor, peroxisome proliferator activated receptor gamma (PPARgamma), independently of CB1 and CB2. Additional results are present suggesting that the specific mechanism involves the disruption of the nuclear factor of activated T cells (NFAT) by PPARgamma activation. Based on the observations described above and other preliminary data presented in the proposal, our present investigation will test the hypothesis: Suppression of IL-2 by the endocannabinoids, AEA and 2-AG, is mediated through disruption of NFAT regulation by two distinct cannabinoid receptor-independent mechanisms: (a) altered intracellular calcium regulation; and (b) activation of PPARgamma following COX-2-mediated conversion of AEA and 2-AG into PPARgamma agonists. We will test our hypothesis using the following specific aims (SA): SA1 is to characterize the role altered intracellular calcium regulation by AEA and 2-AG plays in deregulation of NFAT and, consequently, suppression of IL-2 gene expression; SA2 is to characterize the role of COX-2 on the deregulation of NFAT and suppression of IL-2 by AEA and 2-AG; SA3 is to characterize the role of PPARgamma activation by AEA and 2-AG treatment in altered NFAT regulation and suppression of IL-2; and SA4 is to identify and characterize the bioactive forms of AEA and 2-AG responsible for PPARgamma activation and to elucidate its contribution to IL- 2 suppression.