Mechanistic studies of 2-AG inactivation inhibitors as antidepressants

描述（由申请人提供）：抑郁症是一种使人衰弱并危及生命的疾病，影响着全世界数百万人。临床可用的抗抑郁药具有相同的核心机制，即增强单胺在大脑中的传递。这种疾病的高患病率和现有治疗方法的有限有效性表明，寻找新的治疗靶点治疗抑郁症的重要性和紧迫性。过去十年的临床和实验室观察表明，内源性大麻素（eCB）系统代表了抑郁症药物治疗的一个有希望的目标。在治疗肥胖的临床试验中，CB1大麻素受体拮抗剂利莫那班增加了焦虑和抑郁的发生率，而大麻改善人类情绪，CB1激动剂在抑郁症动物模型中产生抗抑郁样作用。eCB灭活抑制剂以时间和空间特异性的方式增强内源性eCB活性，作为治疗剂应优于直接CB1受体激动剂。eCB配体2-花生四烯醇甘油（2- ag）被单酰基甘油脂肪酶（MAGL）和丝氨酸水解酶α - β -水解酶结构域6和12 （ABHD6/12）灭活。然而，在抑郁症动物模型中，抑制MAGL或ABHD6/12是否产生抗抑郁作用尚不清楚。随着选择性和有效的MAGL抑制剂JZL184和ABHD6抑制剂WWL123的合成，解决这一重要问题成为可能。使用慢性轻度不可预测应激（CUS）作为抑郁症的动物模型，我们验证了2-AG信号在抑郁症中受损的假设，以及用MAGL或ABHD6抑制剂阻断2-AG失活通过挽救2-AG信号缺失产生抗抑郁样作用。我们将通过两个具体目的来验证这一假设：(1)验证2-AG信号在抑郁症CUS模型中受损的假设；(2)验证MAGL或ABHD6阻断通过挽救cu诱导的2- ag信号损伤而产生抗抑郁样作用的假设。在第一个目标下，我们将记录2-AG介导的电生理反应，以询问抑郁症CUS模型中海马中2-AG信号的持续状态。在第二个目标下，我们将研究体内慢性或亚慢性给药JZL184或WWL123是否通过挽救CUS诱导的eCB信号缺陷而产生抗抑郁样作用。我们还将研究MAGL敲除小鼠是否表现出抗抑郁样表型。这项研究的完成将导致抑郁症药物治疗的新靶点的确定和验证，并将提供一个更好的理解情绪调节机制和抑郁症的病因。

DESCRIPTION (provided by applicant): Depression is a debilitating and life-threatening disease that affects millions of people worldwide. The clinically available antidepressants share the same core mechanisms of enhancing monoamine transmission in the brain. The high prevalence of the disease and limited effectiveness of current treatments indicate the importance and urgency to find novel therapeutic targets for the treatment of depression. Clinical and laboratory observations over the last decade indicate that the endocannabinoid (eCB) system represents a promising target for the pharmacotherapy of depression. The CB1 cannabinoid receptor antagonist rimonabant increases the incidence of anxiety and depression in clinical trials for the treatment of obesity, whereas cannabis improves mood in humans and CB1 agonists produce antidepressant-like effects in animal models of depression. Inhibitors of eCB inactivation amplify endogenous eCB activity in a temporal- and spatial-specific manner and should be superior to direct CB1 receptor agonists as therapeutic agents. The eCB ligand 2- arachidonoylglycerol (2-AG) is inactivated by monoacylglycerol lipase (MAGL) and serine hydrolase alpha- beta-hydrolase domain 6 and 12 (ABHD6/12). However, it remains unknown whether inhibition of MAGL or ABHD6/12 produces antidepressant effects in animal models of depression. Addressing this important question became possible now with the recent synthesis of selective and potent MAGL inhibitor JZL184 and ABHD6 inhibitor WWL123. Using chronic mild unpredictable stress (CUS) as an animal model for depression, we test the hypothesis that the 2-AG signaling is impaired in depression and the blockade of 2-AG inactivation with MAGL or ABHD6 inhibitors produces antidepressant-like effects by rescuing the deficiency in 2-AG signaling. We will test this hypothesis through two specific aims: (1) Test the hypothesis that 2-AG signaling is impaired in CUS model of depression; and (2) Test the hypothesis that MAGL or ABHD6 blockade produces antidepressant-like effects by rescuing CUS-induced impairment of 2-AG signaling. Under the first Aim, we will record 2-AG-mediated electrophysiological responses to interrogate ongoing status of 2-AG signaling in the hippocampus in a CUS model of depression. Under the second aim, we will examine whether in vivo chronic or subchronic administration of JZL184 or WWL123 produces antidepressant-like effects by rescuing CUS- induced deficiency in eCB signaling. We will also examine whether MAGL knockout mice exhibit antidepressant-like phenotypes. Completion of this investigation will lead to the identification and validation of new therapeutic targets for pharmacotherapy of depression and will provide an improved understanding of the mechanisms of mood regulation and the etiology of depression. PUBLIC HEALTH RELEVANCE: The proposed research investigates the antidepressant effects of inhibitors of endocannabinoid inactivation in an animal model of depression. Completion of this project will contribute knowledge at both mechanistic and practical levels for the development and testing of therapeutic strategies for pharmacological intervention of depression.