Microarray Studies Identify the Anti-Apoptotic, GR Chap.

情绪稳定剂锂和丙戊酸盐在双相情感障碍的治疗中均有效;然而，其治疗机制尚不清楚。由于临床疗效的延迟起效（数天至数周），有人提出基因表达的适应性变化，而不是最初的药理作用，可能是直接原因。利用基因芯片作为初步筛选方法，我们发现，慢性给药的两种药物在治疗剂量增加BAG-1（bcl-2相关的athanogene）在大鼠海马的表达。此外，这些发现在海马体中在蛋白质水平上得到了验证，在与治疗效果一致的时间范围内观察到了效果，并且对情绪稳定剂具有特异性。BAG-1是bcl-2（B-cell CLL/lymphoma 2）的重要分子伴侣，并增强bcl-2？抗凋亡功能;此外，通过与raf（v-raf-1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（促分裂原活化蛋白）激酶。与此一致，我们先前发现锂和丙戊酸盐激活ERK MAP激酶。Bag-1还抑制GR（糖皮质激素受体）激活，这可能会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抗体免疫染色加上DAPI（4 '，6-二脒基-2-苯基吲哚）双重染色显示，治疗相关水平的锂或VPA抑制地塞米松诱导的GR核转位。此外，糖皮质激素反应元件（GRE）转染试验表明，锂，在治疗相关水平，抑制GR活性在培养的人细胞。通过BAG-1的siRNA（短干扰RNA）沉默评估，情绪稳定剂对GR核易位和GR活性的抑制至少部分地由BAG-1介导。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抵消双相情感障碍中观察到的高皮质醇血症的有害作用。在野生型和BAG-1转基因小鼠中使用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弹性表型。在高架十字迷宫测试中，小鼠表现出较少的焦虑相关行为和更多的探索型活动。对抑郁样行为进行了三次测试。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，转基因小鼠在一个压力更大的测试中，即习得性无助范例中，迅速从无助中恢复过来。还进行了两项与躁狂症相关的测试。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。BAG 1转基因小鼠的行为表型也与应激相关蛋白包括Hsp 70、GR和FKBP 51的海马改变相关。总之，这些数据表明，BAG-1可能代表了双相情感障碍长期治疗中的一种新的、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.