Microarray Studies Identify the Anti-Apoptotic, GR Chap.

心境稳定剂锂和丙戊酸盐对双相情感障碍的治疗均有效；然而，它们的治疗机制尚不清楚。由于临床疗效的延迟发作（几天到几周），有人提出基因表达的适应性变化，而不是最初的药物作用，可能直接负责。利用cDNA微阵列作为初始筛选方法，我们发现两种药物在治疗剂量下的慢性给药增加了大鼠海马中BAG-1 （bcl-2相关的thanogene）的表达。此外，这些发现在蛋白质水平上在海马体中得到了验证，其效果在与治疗效果一致的时间框架内被观察到，并且是特定于情绪稳定剂的。BAG -1是bcl-2 （b细胞CLL/淋巴瘤2）的重要伴侣，可增强bcl-2？S抗凋亡功能；此外，通过与raf （v-raf-1小鼠白血病病毒癌基因同源物1）的相互作用，BAG-1能够激活ERK（细胞外信号调节蛋白激酶）MAP（丝裂原活化蛋白）激酶。与此一致，我们之前发现锂和丙戊酸激活ERK MAP激酶。Bag-1还抑制GR（糖皮质激素受体）的激活，这可能抵消双相情感障碍中高皮质血症的有害影响。抗GR抗体免疫染色和DAPI（4′，6-二氨基-2-苯基吲哚）双染色显示，在治疗相关水平上，锂或VPA均能抑制地塞米松诱导的GR核易位。此外，糖皮质激素反应元件（GRE）转染试验显示，在治疗相关水平下，锂可以抑制培养的人细胞中的GR活性。通过对BAG-1的siRNA（短干扰RNA）沉默来评估，情绪稳定剂对GR核易位和GR活性的抑制作用至少部分是由BAG-1介导的。BAG-1抑制糖皮质激素激活的作用表明，情绪稳定剂可能通过上调BAG-1来抵消双相情感障碍中出现的高皮质血症的有害影响。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BAG-1在与情绪障碍相关的行为可塑性中的作用。初步发现BAG-1转基因小鼠表现出行为弹性表型。在升高加迷宫测试中，小鼠表现出较少的焦虑相关活动和更多的探索型活动。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悬尾试验中的表现与野生型小鼠相似。然而，转基因小鼠在压力更大的习得性无助范式测试中迅速从无助中恢复过来。还进行了两项躁狂相关的测试。小鼠在安非他命激发试验中表现出更强的运动稳定性，在可卡因诱导的行为致敏试验中表现出更强的抵抗性。BAG1转基因小鼠的行为表型也与海马应激相关蛋白（包括Hsp70、GR和FKBP51）的改变有关。总之，这些数据表明BAG-1可能在双相情感障碍的长期治疗中代表了一种新的、高度治疗相关的靶点，并在情绪稳定中发挥作用。

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.