Microarray Studies Identify the Anti-Apoptotic, GR Chap.

情绪稳定剂锂和丙戊酸盐在治疗双相情感障碍方面都很有效；然而，它们的治疗机制尚不清楚。由于临床疗效的延迟起效(几天到几周)，有人认为可能是基因表达的适应性变化，而不是最初的药物作用，可能是直接原因。以基因芯片为初步筛选方法，我们发现两种药物在治疗剂量下的慢性给药均增加了BAG-1(bcl2相关基因)在大鼠海马区的表达。此外，这些发现在海马区的蛋白质水平上得到了验证，其效果与治疗效果一致，并且是情绪稳定剂所特有的。BAG-1是BCL-2(B细胞CLL/淋巴瘤2)的重要伴侣，增强了BCL-2、S的抗凋亡功能，并通过与RAF(v-RAF-1小鼠白血病病毒癌基因同源1)相互作用，激活细胞外信号调节蛋白激酶(ERK)MAP(丝裂原活化蛋白)。与此相一致，我们先前发现锂和丙戊酸激活ERK映射激酶。BAG-1还抑制糖皮质激素受体(GR)的激活，这可能抵消双相情感障碍中出现的高皮质醇血症的有害影响。抗GR抗体免疫染色和DAPI(4‘，6-二氨基苯基吲哚)双重染色显示锂或VPA在治疗相关水平上可抑制地塞米松诱导的GR核移位。此外，糖皮质激素反应元件(GRE)转染实验表明，锂在治疗相关水平上抑制了培养的人细胞中GR的活性。通过siRNA(短干扰RNA)沉默BAG-1进行评估，情绪稳定剂对GR核转位和GR活性的抑制至少部分是通过BAG-1介导的。BAG-1抑制糖皮质激素激活的效果表明，情绪稳定剂可能通过上调BAG-1来抵消双相情感障碍中的高皮质醇血症的有害影响。在野生型和BAG-1转基因小鼠中，通过一系列行为测试，进一步研究了BAG-1在与情绪障碍相关的行为可塑性中的作用。初步研究结果表明，BAG-1转基因小鼠表现出行为韧性表型。在高架加迷宫测试中，小鼠表现出较少的焦虑相关和更多的探索性活动。对抑郁样行为进行了三项测试。转基因小鼠在强迫游泳试验和尾部悬挂试验中的表现与野生型小鼠相似。然而，在一项更有压力的测试中，转基因小鼠很快从无助中恢复过来，这是一种习得无助范式。还进行了两项与躁狂相关的测试。小鼠在苯丙胺激发试验中表现出更高的运动稳定性，在可卡因诱导的行为敏化试验中表现出更强的抵抗力。BAG1转基因小鼠的行为表型还与海马区Hsp70、GR和FKBP51等应激相关蛋白的变化有关。综上所述，这些数据表明，BAG-1可能代表着一种新的、高度治疗相关的靶点，用于双相情感障碍的长期治疗，并在情绪稳定方面发挥作用。

The mood stabilizers lithium and valproate are both effective in the treatment of bipolar disorder; however, their therapeutic mechanisms remain unclear. Because of the delayed onset of clinical efficacy (days to weeks), it has been proposed that adaptive changes in gene expression, rather than initial pharmacological actions, may be directly responsible. Using cDNA microarray as the initial screening method, we discovered that chronic administration of both agents at therapeutic doses increased the expression of BAG-1 (bcl-2 associated athanogene) in rat hippocampus. Furthermore, these findings were validated in the hippocampus at the protein level, the effects were seen in a time frame consistent with therapeutic effects, and were specific for mood stabilizers. BAG -1 is an important chaperone of bcl-2 (B-cell CLL/lymphoma 2), and enhances bcl-2?s anti-apoptotic functions; furthermore, through interaction with raf (v-raf-1 murine leukemia viral oncogene homolog 1), BAG-1 is able to activate ERK (extracellular signal-regulated protein kinase) MAP (mitogen-activated protein) kinases. Consistent with this, we previously found that lithium and valproate activate ERK MAP kinases. Bag-1 also inhibits GR (glucocorticoid receptor) activation, which may counteract the deleterious effects of hypercortisolemia seen in bipolar disorder. Anti-GR antibody immunostaining plus double staining with DAPI (4',6-Diamidino-2-phenylindole) showed either lithium or VPA, at therapeutically relevant levels, inhibited dexamethasone induced GR nuclear translocation. In addition, glucocorticoid response element (GRE) transfection assay showed lithium, at therapeutically relevant levels, inhibited GR activity in cultured human cells. Evaluated through siRNA (short interference RNA) silencing of BAG-1, the inhibition of mood stabilizers to GR nuclear translocation and to GR activity is mediated, at least in part, by BAG-1. The effect that BAG-1 inhibits glucocorticoid activation suggests mood stabilizers may counteract the deleterious effects of hypercortisolemia seen in bipolar disorder by up-regulating BAG-1. The role of BAG-1 in behavioral plasticity relevant to mood disorders was further investigated in wild-type and BAG-1 transgenic mice using a battery of behavioral tests. Initial findings suggest BAG-1 transgenic mice display a behavioral resilience phenotype. The mice showed less anxiety-related and more exploration-type activities in the elevated plus maze test. Three tests for depression-like behavior were conducted. The transgenic mice performed similarly to wild type mice on the forced swim test and the tail suspension test. However, transgenic mice were rapidly recovered from helplessness on a more stressful test, the learned helplessness paradigm. Two mania-related tests were also performed. The mice showed more locomotion stability in the amphetamine challenge test and more resistant in cocaine induced behavioral sensitization test. The behavioral phenotype of BAG1 transgenice mice is also associated with hippocampal alterations of stress-related proteins including Hsp70, GR and FKBP51. Together, the data suggests that BAG-1 may represent a novel, highly therapeutically relevant target in the long-term treatment of bipolar disorder and play role in mood stability.