Neuroendocrine Stress Response in Inflammatory & Behavio

神经内分泌免疫和行为(SNIB)部分的研究集中在(项目1)近交系大鼠下丘脑-垂体-肾上腺(HPA)轴差异性调控的分子基础及其与炎症性疾病易感性的关系，(项目2)炭疽芽孢杆菌致死毒素(LeTx)对糖皮质激素受体和其他核激素受体的抑制及其在炎症性休克中的作用。 在项目1中，我们已经开始探索暴露于细菌细胞壁产品的啮齿动物大脑中免疫分子(细胞因子和趋化因子)的表达。初步结果表明，在这些条件下，某些免疫分子(趋化因子)在大脑内表达。 项目2侧重于验证和阐明我们发现的炭疽芽孢杆菌致命毒素(LeTx)是包括糖皮质激素受体(GR)和孕激素受体(PR)在内的核激素受体的有效和选择性抑制物的分子机制和治疗意义。这些发现对炭疽、LeTx和其他细菌毒素的治疗和预防具有重要意义。毒性和致命性。我们跟进了最初的研究，发现纳摩尔浓度的LeTx选择性地抑制核激素受体的活性，包括糖皮质激素受体(GR)、孕激素受体(PR)和雌激素受体(ER)α，但不抑制盐皮质激素受体(MR)或ERβ。由于GR拮抗剂或阻断下丘脑-垂体-肾上腺(HPA)轴使其他抗休克动物对许多细菌产物的致死作用高度敏感，我们推测LeTx抑制GR和其他核激素受体可能参与了炭疽的毒性和致死性。在随后的研究中，我们已经证明，肾上腺切除阻断HPA轴与增加其他LeTx抗性小鼠的LeTx死亡率有关。此外，用糖皮质激素治疗小鼠与增加死亡率有关。后续的分子研究表明，核激素受体的选择性抑制部分依赖于受体，部分依赖于启动子。染色质免疫沉淀(ChIP)实验表明，LeTx抑制GR与启动子的结合，导致靶基因中聚合酶II结合和组蛋白H3乙酰化的丧失。电泳迁移率改变分析(EMSA)表明，这种抑制不是由于Lf？PA与GR-GRE复合体。综上所述，这些发现表明，LeTx通过影响辅因子(S)或受体的修饰来抑制GR活性。这些发现和体内研究表明，抵抗炭疽致命毒素需要完整的HPA轴(神经内分泌反应)，简单的糖皮质激素替代可能是不够的，可能对炭疽LeTx休克的治疗不利。

The research of the Section on Neuroendocrine Immunology and Behavior (SNIB) focuses on (Project 1) molecular basis of differential hypothalamic pituitary adrenal (HPA) axis regulation in inbred rat strains and its relationship to inflammatory disease susceptibility and (Project 2) repression of the glucocorticoid receptor and other nuclear hormone receptors by Bacillus anthracis (anthrax) lethal toxin (LeTx) and its role in inflammatory shock. In Project 1, we have begun to explore the expression within the brain of immune molecules (cytokines and chemokines) in rodents exposed to bacterial cell wall products. Preliminary results indicate that certain immune molecules (chemokines) are expressed within the brain under these conditions. Project 2 focuses on validation and elucidation of the molecular mechanisms and therapeutic implications of our finding that Bacillus anthracis lethal toxin (LeTx) is a potent and selective repressor of nuclear hormone receptors, including the glucocorticoid receptor (GR) and progesterone receptor (PR). These findings have important implications for treatment and prevention of anthrax LeTx and other bacterial toxins? toxicity and lethality. We followed up on initial studies showing that nanomolar concentrations of LeTx selectively repress nuclear hormone receptor activity, including the glucocorticoid receptor (GR), the progesterone receptor (PR) and the estrogen receptor (ER) alpha but not the mineralocorticoid receptor (MR) or ER beta. Since GR antagonists or interruptions of the hypothalamic-pituitary-adrenal (HPA) axis render otherwise shock-resistant animals highly susceptible to the lethal effects of many bacterial products, we postulated that LeTx repression of GR and other nuclear hormone receptors might contribute to anthrax toxicity and lethality. In subsequent studies we have shown that interruption of the HPA axis by adrenalectomy is associated with enhanced LeTx mortality in otherwise LeTx resistant mouse strains. Furthermore, treatment of mice with glucorticoids was associated with enhanced mortality. Follow-up molecular studies show selective repression of nuclear hormone receptors that is partially receptor and partially promoter dependent. Chromatin immunoprecipitation (ChIP) experiments indicate that LeTx inhibits GR binding to the promoter, resulting in loss of both polymerase II binding and acetylation of histone H3 in target genes. Electrophoretic mobility shift assays (EMSA) indicate that this inhibition is not due to direct interaction of LF ? PA with the GR-GRE complex. Taken together, these findings indicate that LeTx represses GR activity through its effects on co-factor(s), or modification of the receptor. These findings together with the in vivo studies indicate that an intact HPA axis (neuroendocrine response) is required for resistance to anthrax lethal toxin, and that simple glucocorticoid replacement may not be sufficient and might be detrimental as a therapy for anthrax LeTx shock.