ROLE OF OPIOIDS SIGNALING IN IMMUNE SUPPRESSION

描述(申请人提供)：这些研究的总体目标是确定阿片介导的免疫抑制信号的潜在机制(S)。生理和心理应激对人和动物的免疫系统都有深远的影响。压力也是许多人类疾病的已知风险因素，如传染病和自身免疫性疾病。我们实验室和其他机构的研究支持这一假设，即应激源通过应激激素(如内源性阿片类药物)调节免疫功能，而不是仅通过糖皮质激素。我们已经报道，物理应激以内源性阿片类药物依赖的方式诱导淋巴细胞凋亡。然而，应激影响免疫系统的机制仍有待阐明。在上一次授予期间，我们报道了磷脂酰肌醇3-激酶(PI3K)/Akt信号转导通路参与了应激后的免疫反应。我们的体外研究表明，阿片类药物通过PI3K启动淋巴细胞凋亡。我们的初步结果表明，慢性应激抑制T细胞介导的免疫反应。此外，我们发现5阿片受体(5阿片受体，MOR)是一种新的应激诱导淋巴细胞凋亡的受体。我们的体外研究表明，糖原合成酶激酶32(GSK32)是MOR介导的细胞凋亡所必需的。我们和其他人发现，MOR的功能受2-arrestin 2的调节，2-arrestin 2是一个多功能的适配器和信号转导。我们的体外实验结果表明，2-arrestin 2通过p38丝裂原活化蛋白激酶(MAPK)抑制淋巴细胞的凋亡。此外，我们还发现2-arrestin 2在应激诱导的淋巴细胞减少中起作用。然而，MOR和2-arrestin 2对应激诱导的免疫抑制的作用机制尚不清楚。我们的假设是，MOR和2-arrestin 2介导的通路在免疫抑制中起关键作用。此外，我们推测其机制涉及MOR介导的PI3K和GSK32通路，以及2-arrestin 2介导的p38MAPK信号转导。为了验证这一假设，我们将追求两个目标。目的1研究PI3K和GSK32在MOR介导的免疫抑制中的作用。我们将用或不用PI3K/GSK3抑制剂治疗MOR基因敲除小鼠和野生型小鼠，然后让它们在不同的时间段接受物理应激。我们将首先确定MOR介导的PI3K信号通路在应激诱导的免疫抑制中的作用，然后研究MOR介导的GSK32信号在应激诱导的淋巴细胞凋亡中的作用。目的2确定p38MAPK在2-arrestin 2介导的免疫抑制中的作用。2-arrestin 2基因敲除小鼠和野生型小鼠分别给予p38 MAPK抑制剂，然后接受物理应激，以探讨2-arrestin 2介导的p38 MAPK信号在应激免疫抑制中的作用。此外，2-arrestin 2对正在形成的和已建立的免疫反应的影响将被检测。这些研究将使我们了解阿片介导的信号对免疫系统的影响，为开发新的免疫抑制策略和治疗方法提供机会。 公共卫生相关性：心理和身体压力会对免疫系统产生显著影响。从历史上看，这种影响归因于压力荷尔蒙的释放，尽管其他因素似乎起到了重要作用。利用物理束缚应激的小鼠模型，我们研究了一些可能解释应激和免疫系统之间联系的分子介体。这项研究将研究应激影响免疫系统的机制，希望能导致特定治疗方法或药物的开发，进而可能改善这种有时有害的相互作用。

DESCRIPTION (provided by applicant): The overall goal of these studies is to determine the mechanism(s) underlying opioid-mediated signaling in immune suppression. Physical and psychological stress has profound effects on the immune system of humans and animals. Stress is also a known risk factor for many human diseases, such as infectious and autoimmune diseases. Studies from our laboratory and others support the hypothesis that stressors modulate immune function through stress hormones such as endogenous opioids, other than exclusively glucocorticoids. We have reported that physical stress induces lymphocyte apoptosis in an endogenous opioid-dependent manner. However, the mechanisms by which stress affects the immune system remain to be elucidated. During the last grant period, we reported that phosphatidylinositol 3-kinase (PI3K)/Akt signaling is involved in immune responses following stress. Our in vitro studies have shown that opioids prime lymphocyte apoptosis via PI3K. Our preliminary results showed that chronic stress inhibits T cell mediated immune responses. Moreover, we found that 5 opioid receptor (MOR) is a novel receptor in stress-induced lymphocyte apoptosis. Our in vitro studies showed that glycogen synthase kinase 32 (GSK32) is required for MOR-mediated apoptosis. We and others revealed that the function of MOR is regulated by 2-arrestin 2, a multifunctional adaptor and signal transducer. Our in vitro results showed that 2-arrestin 2 inhibits lymphocyte apoptosis through p38 mitogen-activated protein kinase (MAPK). In addition, we also found that 2-arrestin 2 plays a role in stress-induced lymphocyte reduction. However, the mechanisms by which MOR and 2-arrestin 2 contribute to stress-induced immune suppression are unclear. Our hypothesis is that MOR and 2-arrestin 2 mediated pathways are critical to immune suppression. Moreover, we postulate that the mechanisms involve the MOR-mediated PI3K and GSK32 pathways, and 2-arrestin 2 mediated p38 MAPK signaling. To test this hypothesis, we will pursue two aims. Aim 1 will examine the role of PI3K and GSK32 in MOR- mediated immune suppression. We will treat MOR knockout mice and wild type mice with or without PI3K/GSK3 inhibitors, and then subject them to physical stress for different time periods. We will first define the role of MOR-mediated PI3K signaling pathway in immune suppression induced by stress, and next examine the effects of MOR-mediated GSK32 signaling on stress-induced lymphocyte apoptosis. Aim 2 will define the contribution of p38 MAPK in 2-arrestin 2-mediated immune suppression. 2-arrestin 2 knockout mice and wild type mice will be administrated p38 MAPK inhibitor, and then subjected to physical stress to investigate role of 2-arrestin 2 mediated p38 MAPK signaling in immune suppression following stress. In addition, the effects of 2-arrestin 2 on a developing and an established immune response will be examined. These studies should lead to our understanding of the effects of opioid-mediated signaling on the immune system, providing the opportunity to develop novel strategies and therapeutics for immune suppression. PUBLIC HEALTH RELEVANCE: Psychological and Physical stress 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 physical restraint stress we have investigated 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.