Role Of Neuroendocrine Stress Response In Inflammatory A

神经内分泌免疫学和行为科（SNIB）的研究主要集中在(1)大鼠自交系下丘脑垂体肾上腺（HPA）轴差异调节的分子基础及其与炎性疾病易感性的关系；(2)糖皮质激素受体（GR）在自身免疫性/炎性疾病中的作用，包括炭疽芽孢杆菌（炭疽）致死毒素（LeTx）对糖皮质激素和其他核激素受体的抑制。在Project 1中，我们之前的遗传连锁和分离研究发现了10号染色体上一个包含CRH受体1型（CRH- r1）基因的区域，该区域与相对HPA轴低反应和高反应的近亲LEW/N和F344/N大鼠的炎症易感性和抵抗有关。CRH-R1编码区的测序显示，这些菌株之间没有差异，下丘脑CRH-R1 mRNA也没有差异调节，表明CRH-R1基因不太可能是这些菌株差异表型的来源。下丘脑组织细菌前和细菌后脂多糖（LPS）处理的表达微阵列研究和实时RT-PCR显示甲状腺转甲素（TTR）和胆囊收缩素（CCK） mRNA表达差异，提示可能与甲状腺激素失调有关，因为TTR是甲状腺激素的主要转运体。大鼠胎儿下丘脑组织免疫亲和毛细管电泳蛋白定量和实时RT-PCR mRNA均显示LEW/N胎儿下丘脑组织中CRH、AVP分泌和促炎因子上调。在GR研究中，我们发现了与类风湿关节炎患者GRb稳定性增强相关的多态性，这可能导致这些患者相对的糖皮质激素耐药。最近我们发现，纳米摩尔浓度的炭疽芽孢杆菌LeTx（致死因子+保护性抗原）选择性地抑制核激素受体的活性，包括GR、孕激素受体（PR）和雌激素受体（ER）a，而不是矿化皮质激素受体（MR）或ERb。这种抑制是非竞争性的，不通过受体发生。并且很可能是LeTx与核激素受体辅助因子相互作用的结果。这种抑制在体外瞬时转染系统和糖皮质激素调节酶(肝细胞酪氨酸氨基转移酶？TAT)和体内（抑制肝脏TAT激活）。这种抑制在炭疽毒性中的作用仍有待确定。

The research of the Section on Neuroendocrine Immunology and Behavior (SNIB) focuses on (1) molecular basis of differential hypothalamic pituitary adrenal (HPA) axis regulation in inbred rat strains and its relationship to inflammatory disease susceptibility and (2) role of the glucocorticoid receptor (GR) in autoimmune/inflammatory disease, including Bacillus anthracis (anthrax) lethal toxin (LeTx) repression of the glucocorticoid and other nuclear hormone receptors. In Project 1, our prior genetic linkage and segregation studies identified a region on chromosome 10, containing the CRH receptor type 1 (CRH-R1) gene, that linked to inflammatory susceptibility and resistance in relatively HPA axis hypo- and hyper-responsive inbred LEW/N and F344/N rats. Sequencing of the CRH-R1coding region showed no differences in these strains and hypothalamic CRH-R1 mRNA was not differentially regulated, indicating that the CRH-R1 gene is unlikely to be the source of the differential phenotypes in these strains. Expression microarray studies and real-time RT-PCR of hypothalamic tissue pre- and post-bacterial lipopolysaccharide (LPS) treatment indicated differential transthyretin (TTR) and cholecystokinin (CCK) mRNA expression, suggesting a possible role for thyroid hormone dysregulation, since TTR is a major thyroid hormone transporter. Both immunoaffinity capillary electrophoresis protein quantitation and real-time RT-PCR mRNA in rat fetal hypothalamic tissue indicated that CRH and AVP secretion and pro-inflammatory cytokines are up-regulated in LEW/N fetal hypothalamic tissue. In GR studies, we found a polymorphism associated with enhanced stability of the GRb in human rheumatoid arthritis patients that could lead to relative glucocorticoid resistance in these patients. Most recently we found that nanomolar concentrations of Bacillus anthracis LeTx (lethal factor + protective antigen) selectively repress nuclear hormone receptor activity, including GR, the progesterone receptor (PR) and the estrogen receptor (ER)a but not the mineralocorticoid receptor (MR) or ERb. This repression is non-competitive, and does not occur through the receptor?s ligand binding or DNA binding domains, and most likely results from LeTx interaction with nuclear hormone receptor co-factors. The repression is seen in vitro both in a transient transfection system and at the level of activity of a glucocorticoid regulated enzyme (hepatocyte tyrosine amino transferase ? TAT), and in vivo (repression of hepatic TAT activation). The role of this repression in anthrax toxicity remains to be determined.