Role of Opioids Signaling in Immune Suppression

描述（由申请人提供）：生理和心理压力可以改变人类和动物的免疫系统。压力也是一些人类疾病的已知风险因素，如自身免疫性疾病和艾滋病。先前的研究支持这样的假设，即压力源通过应激激素（如内源性阿片样物质）调节免疫功能，而不仅仅是糖皮质激素。然而，压力影响免疫和神经内分泌系统的机制仍有待阐明。在上一个资助期内，我们发现小鼠抑制应激通过抗凋亡磷脂酰肌醇3-激酶（PI3K）和核因子- κ b （NF-kB）途径诱导免疫抑制。我们发现小鼠的抑制应激以p53依赖的促凋亡方式诱导淋巴细胞减少。然而，PI3K/NF-kB和p53参与免疫抑制的确切机制尚不清楚。这个修订后的应用程序的长期目标是确定分子机制的压力调节免疫抑制。有趣的是，我们最近发现了一种新的内源性抑制剂，¿-arrestin 2，一种多功能适配器和信号传感器，它通过激活抗凋亡PI3K和抑制促凋亡p53途径来抑制细胞凋亡。此外，我们发现缺乏¿-阻滞蛋白2的小鼠对抑制应激诱导的淋巴细胞减少的敏感性显著增强。捕集素2调节阿片受体（MOR）的功能。此外，MOR基因敲除小鼠对应激诱导的淋巴细胞减少有显著的抑制作用。我们的研究结果表明，特异性MOR激动剂通过NF-kB和p38丝裂原活化蛋白激酶（MAPK）途径诱导T细胞功能障碍。我们的总体假设是，¿-阻滞蛋白2和MOR信号通路对免疫抑制至关重要。此外，我们假设其机制涉及¿-阻滞蛋白2介导的PI3K和p53通路，以及mor介导的NF-kB和p38 MAPK通路。第一个目的是研究PI3K和p53在抑制蛋白2介导的免疫抑制中的作用。我们将对携带或不携带PI3K/p53抑制剂的¿-阻滞蛋白2敲除小鼠和野生型小鼠进行治疗，然后对它们进行抑制应激。我们将首先研究¿- arretin2对应激诱导的免疫抑制的影响，然后确定¿- arretin2介导的PI3K激活和p53信号抑制在免疫抑制中的作用。第二个目的是确定NF-kB和p38 MAPK在mor介导的免疫抑制中的作用。MOR基因敲除小鼠和野生型小鼠将使用或不使用NF-kB/p38 MAPK抑制剂进行治疗，然后对其进行物理约束。我们将首先定义MOR在应激诱导的免疫抑制中的作用，然后研究MOR介导的NF-kB和p38 MAPK信号在免疫抑制中的作用。这些研究应该描述应激诱导的免疫抑制机制，为开发新的免疫抑制策略和治疗方法提供机会。

DESCRIPTION (provided by applicant): Physical and psychological stress can alter the immune system in both humans and animals. Stress is also a known risk factor for some human diseases, such as autoimmune diseases and AIDS. Previous studies support the hypothesis that stressors modulate immune function through stress hormones such as endogenous opioids, other than exclusively glucocorticoids. However, the mechanisms by which stress affects the immune and neuroendocrine systems remain to be elucidated. During the last grant period, we discovered that restraint stress of mice induces immune suppression through the anti-apoptotic phosphatidylinositol 3-kinase (PI3K) and nuclear factor-kappaB (NF-kB) pathways. We have revealed that restraint stress of mice induces lymphocyte reduction in a pro-apoptotic p53-dependent manner. However, the precise mechanisms by which PI3K/NF-kB and p53 contribute to immune suppression are not known. The long-term goals of this revised application are to define the molecular mechanisms by which stress modulates immune suppression. Interestingly, we have recently identified a new endogenous inhibitor, ¿-arrestin 2, a multifunctional adaptor and a signal transducer, which inhibit cell apoptosis through activation of anti-apoptotic PI3K and inhibition of pro-apoptotic p53 pathways in vitro. Moreover, we have found that mice with a deficiency in ¿-arrestin 2 have dramatically enhanced sensitivity to restraint stress induced lymphocyte reduction. ¿-arrestin 2 regulates the function of ¿ opioid receptor (MOR). In addition, MOR knockout mice have a significant inhibition of stress-induced reduction in lymphocytes. Our results showed that the specific MOR agonist induces T cell dysfunction through NF-kB and p38 mitogen-activated protein kinase (MAPK) pathways. Our overall hypothesis is that ¿-arrestin 2 and MOR signaling pathways are critical to immune suppression. Moreover, we postulate that the mechanisms involve in the ¿-arrestin 2 mediated PI3K and p53 pathways, and MOR-mediated NF-kB and p38 MAPK pathways. The first aim is to investigate the role of PI3K and p53 in ¿ -arrestin 2-mediated immune suppression. We will treat ¿ -arrestin 2 knockout mice and wild type mice with or without PI3K/p53 inhibitors, and then subject them to restraint stress. We will first examine the effects of ¿ -arrestin 2 on stress-induced immune suppression, and next define the role of ¿-arrestin 2 mediated activation of PI3K and inhibition of p53 signaling in immune suppression. The second aim is to determine the contribution of NF-kB and p38 MAPK in MOR-mediated immune suppression. MOR knockout mice and wild type mice will be treated with or without NF-kB/p38 MAPK inhibitors and then subject them to physical restraint. We will first define the role of MOR in stress-induced immune suppression, and then examine the role of MOR-mediated NF-kB and p38 MAPK signaling in immune suppression. These studies should delineate the mechanisms underlying immune suppression induced by stress, providing the opportunity to develop novel strategies and therapeutics for immune suppression. PUBLIC HEALTH RELEVANCE: Stress, both physical and psychological, can have pronounced effects on the immune system. Historically this affect was attributed to the release of stress hormones although other factors appear to play an important role. Using a mouse model of restraint stress, we have determined some of the molecular mediators which may account for the connection between stress and the immune system. This research will examine the mechanisms whereby the immune system is influenced by stress with the hope of leading to the development of specific treatments or drugs which in turn may ameliorate this sometimes deleterious interaction.