Mast cells, antidepressants and chronic fatigue syndrome

描述(申请人提供)：慢性疲劳综合症(CFS)的特征是疲劳、不适、睡眠和自主神经障碍；它被认为是一种神经免疫紊乱，下丘脑-垂体-肾上腺(HPA)轴调节失调，由应激诱发，并与高度残疾有关。CFS通常与纤维肌痛、肠易激综合征(IBS)、间质性膀胱炎(IC)和偏头痛等并存疾病一起发生，所有这些疾病都会因应激而恶化。目前尚无可靠的CFS动物模型。肥大细胞已成为受应激影响的神经免疫内分泌过程的主要调节细胞，并与所有与慢性疲劳综合征相关的并存疾病有关。我们已经证明：(A)肥大细胞与神经末梢有功能联系；(B)急性应激激活肥大细胞，这一作用可被促肾上腺皮质激素释放激素(CRH)中和抗血清所阻断；(C)应激增加血脑屏障(BBB)通透性，这可被CRH受体-1(CRH-R1)拮抗剂Antalarmin抑制，在肥大细胞缺陷W/W小鼠中不发生；(D)人肥大细胞表达CRH受体，其激活导致血管内皮生长因子(VEGF)选择性释放；(E)CRH对肥大细胞的部分刺激作用是通过神经降压素(NT)介导的，已被证明调节HPA轴。三环类抗抑郁药对慢性疲劳综合征和其他并存疾病有帮助，但其作用机制尚不清楚。我们的初步结果表明，三环类抗抑郁药阿米替林可以抑制大鼠肥大细胞的分泌和细胞内钙离子水平。假设：应激分泌的CRH或结构相关的尿皮质激素(UCN)单独或与其他神经肽(如NT)一起激活间脑肥大细胞，导致参与CFS中枢发病机制的分子释放，其分泌可被三环类抗抑郁药抑制。我们将研究：1.三种不同类型的抗抑郁药(A)三环类(阿米替林，丙咪嗪)，(B)选择性5-羟色胺摄取抑制剂(氟西汀，舍曲林)和(C)安非他酮对正常人脐带来源的肥大细胞(HCBMC)分泌组胺、IL-1、IL-6、IL-8、IL-13、肿瘤坏死因子、类胰蛋白酶和血管内皮生长因子的影响。目的2.这些抗抑郁药物在目标1中被证明是有效的，因为它们能够抑制通过在10 nM IL-4和神经生长因子(NGF)的刺激下培养的CD34-人脐带基质干细胞(HCMSC)而形成的“脑肥大细胞”，如在目标1/-NT(0.1-100 mM)中所刺激的。这些研究的结果将进一步加深我们对应激激素释放的分子的理解，以及哪些抗抑郁药可能有助于抑制这些影响。未来的研究将以这些发现为基础，开发CFS的体外和体内模型，并导致对选定的抗抑郁药物或其他抑制脑肥大细胞的分子进行临床试验。

DESCRIPTION (provided by applicant): Chronic fatigue syndrome (CFS) is characterized by fatigue, malaise, sleep and autonomic disturbances; it is considered a neuroimmune disorder with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, precipitated by stress and associated with high disability. CFS often occurs with comorbid diseases such as fibromyalgia, irritable bowel syndrome (IBS), interstitial cystitis (IC) and migraines, all of which also worsen by stress. There are no reliable animal models for CFS. Mast cells have emerged as a major regulator of neuroimmune endocrine processes affected by stress and have been implicated in all comorbid diseases associated with CFS. We have shown that: (a) mast cells have functional associations with nerve endings; (b) acute stress activates mast cells, an action blocked by pretreatment with corticotropin-releasing hormone (CRH) neutralizing antiserum, (c) stress increases blood-brain-barrier (BBB) permeability, which is inhibited by the CRH-receptor-1 (CRH-R1) antagonist Antalarmin and does not develop in mast cell deficient W/W mice, (d) human mast cells express CRH receptors, activation of which leads to selective release of vascular endothelial growth factor (VEGF), (e) some of the stimulatory effects of CRH on mast cells are mediated by neurotensin (NT), which has been shown to regulate the HPA axis. Tricyclic antidepressants are helpful in CFS and in the other comorbid diseases, but this mechanism of action is unknown. Our preliminary results show that the tricyclic antidepressant amitriptyline can inhibit rat mast cell secretion and intracellular calcium ion levels. Hypothesis: CRH, or the structurally related urocortin (Ucn), secreted by stress activates diencephalic mast cells, either alone or together with other neuropeptides such as NT leading to release of molecules that contribute to the central pathogenesis of CFS, and secretion of which can be inhibited by tricyclic antidepressants. We will investigate: Aim 1. The dose-response (0.1-100 uM) and time-course (0.5,1,6, 24 h) effects of three different classes of antidepressants, (a) the tricyclic (amitriptyline, imipramine), (b) the selective serotonin uptake inhibitors (fluoxetine, sertraline) and (c) bupropion on secretion of histamine, IL-1, IL-6, IL-8, IL-13, TNF, tryptase and VEGF from normal human umbilical cord-derived cultured mast cells (hCBMCs) derived from CD34+ progenitors triggered by IL-1, CRH or Ucn (100 nM). Aim 2. The effect of those antidepressants shown to be effective in Aim 1 for their ability to inhibit "brain mast cells" developed by culturing human umbilical cord matrix stem cells (hCMSCs) that are CD34- in the presence of 10 nM IL-4 and nerve growth factor (NGF), stimulated as in Aim 1 +/- NT (0.1-100 mM). Results from these studies will further our understanding of molecules released in response to stress hormones and which antidepressants may be useful in inhibiting these effects. Future studies will build on these findings to develop in vitro and in vivo models of CFS and lead to clinical trials with select antidepressants or other molecules that inhibit brain mast cells.