Microarray Studies of Anti-Apoptotic, BAG-1 in BPD

BPD 中抗凋亡 BAG-1 的微阵列研究

• 批准号: 6982750
• 负责人: HUSSEINI K MANJI
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF MENTAL HEALTH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6982750
• 关键词: BCL2 gene /protein; RNA interference; apoptosis; biotechnology; bipolar depression; brain mapping; cell growth regulation; cell proliferation; corticosteroid receptors; drug administration rate /duration; drug interactions; glucocorticoids; hippocampus; hormone regulation /control mechanism; human tissue; laboratory rat; lithium; mental disorder chemotherapy; microarray technology; mitogen activated protein kinase; protein quantitation /detection; psychopharmacology; receptor expression; small interfering RNA; stimulant /agonist; transfection; valproate

The mood stabilizers lithium and valproate are both effective in the treatment of bipolar disorder(BD); 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 their initial pharmacological actions, may be directly responsible. To investigate the strategic regulation of signaling pathways and gene expression in critical neuronal circuits likely involved in the long term treatment of bipolar disorder, we used microarray methodologies to identify novel targets of therapeutic relevance with validating criteria including the following: (1) dose and time frame consistent with clinical therapeutic effects; (2) observed with structurally highly dissimilar but clinically efficacious agents; (3) specific to brain regions implicated in the disorder (4) specific for mood stabilizers (5) validated at a protein level. Using these stringent criteria, our recent microarray studies have revealed a novel target for the long-term actions of the mood stabilizers lithium and valproate. 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 found that lithium and valproate activate ERK MAP kinases and exert anti-apoptotic effects. Bag-1 also inhibits GR(glucocorticoid receptor) activation, which may counteract the deleterious effects of hypercortisolemia seen in BD. 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 SH-SY5Y 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 BD by up-regulating BAG-1. Together, the data suggests that BAG-1 may represent a novel, highly therapeutically relevant target in the long-term treatment of bipolar disorder. Complementary human studies have shown that chronic lithium significantly increases gray matter content in a regionally selective manner, suggesting a reversal of illness-related atrophy and an increase in the volume of the neuropil. Interestingly, the gray matter changes are seen in a regionally-specific manner, and are only observed in treatment-responders. The growing body of preclinical/clinical data suggests that for many refractory patients, optimal treatment may only be attained by providing both trophic and neurochemical support; the trophic support would be envisioned as enhancing and maintaining normal synaptic connectivity, thereby allowing the chemical signal to reinstate the optimal functioning of critical circuits necessary for normal affective functioning.

情绪稳定剂锂和丙戊酸盐均能有效治疗双相情感障碍（BD）；然而，它们的治疗机制仍不清楚。由于临床疗效的起效延迟（数天至数周），有人提出，基因表达的适应性变化，而不是其最初的药理作用，可能是直接原因。为了研究可能参与双相情感障碍长期治疗的关键神经元回路中信号通路和基因表达的策略性调节，我们使用微阵列方法来确定具有治疗相关性的新靶点，并验证标准包括以下内容：（1）剂量和时间框架与临床治疗效果一致； (2) 用结构高度不同但临床有效的药物进行观察； (3) 特定于与疾病有关的大脑区域 (4) 特定于情绪稳定剂 (5) 在蛋白质水平上进行验证。利用这些严格的标准，我们最近的微阵列研究揭示了情绪稳定剂锂和丙戊酸的长期作用的新靶点。长期服用治疗剂量的两种药物可增加大鼠海马中 BAG-1（bcl-2 相关的 athanogene）的表达。此外，这些发现在海马体的蛋白质水平上得到了验证，其效果是在与治疗效果一致的时间范围内看到的，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bcl-2的抗凋亡功能；此外，通过与raf（v-raf-1鼠白血病病毒癌基因同源物1）相互作用，BAG-1能够激活ERK（细胞外信号调节蛋白激酶）MAP（丝裂原激活蛋白）激酶。与此一致，我们发现锂和丙戊酸盐激活 ERK MAP 激酶并发挥抗凋亡作用。 Bag-1 还抑制 GR（糖皮质激素受体）激活，这可能抵消 BD 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，锂或 VPA 在治疗相关水平下可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) 转染测定显示，治疗相关水平的锂可抑制 SH-SY5Y 细胞中的 GR 活性。通过 siRNA（短干扰 RNA）沉默 BAG-1 进行评估，情绪稳定剂对 GR 核易位和 GR 活性的抑制至少部分是由 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 BD 中出现的高皮质醇血症的有害影响。总之，数据表明 BAG-1 可能代表双相情感障碍长期治疗中的一个新颖的、高度治疗相关的靶点。补充人体研究表明，长期服用锂盐会以区域选择性的方式显着增加灰质含量，这表明与疾病相关的萎缩得到逆转，神经纤维体积增加。有趣的是，灰质变化以区域特定的方式出现，并且仅在治疗反应者中观察到。越来越多的临床前/临床数据表明，对于许多难治性患者来说，只有同时提供营养和神经化学支持才能获得最佳治疗；营养支持将被设想为增强和维持正常的突触连接，从而允许化学信号恢复正常情感功能所需的关键回路的最佳功能。