Remodeling Neuronal Chromatin in Mouse Models for Depression

重塑抑郁症小鼠模型中的神经元染色质

• 批准号: 8249508
• 负责人: Schahram Akbarian
• 金额: $ 33.88万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8249508
• 关键词: Acetylation; Address; Adult; Antidepressive Agents; Anxiety; Area; Behavioral; Behavioral Assay; Biological Assay; Biophysics; Brain region; Chromatin; Chromatin Structure; Clinical; Clinical Trials; Communication; Complex; DNA; Data; Deacetylase; Depressed mood; Depressive disorder; Diagnosis; Down-Regulation; Electrophysiology (science); Enzymes; Exhibits; Fluoxetine; Foundations; Gene Expression; Gene Targeting; Genes; Genetic; Genetically Engineered Mouse; Genome; Genomics; Genotype; Glutamate Receptor; Health; Hippocampus (Brain); Histone Acetylation; Histone H3; Histones; Hypermethylation; Ketamine; Laboratories; Learned Helplessness; Learning; Link; Lysine; Major Depressive Disorder; Measures; Mediating; Memory; Mental Depression; Mental disorders; Methylation; Molecular; Mood Disorders; Mus; N-Methyl-D-Aspartate Receptors; N-Methylaspartate; NMDA receptor antagonist; Neurobiology; Neurologic; Neurons; NuRD complex; Patients; Pattern; Performance; Pharmaceutical Preparations; Phenotype; Phosphotransferases; Play; Pre-Clinical Model; Prefrontal Cortex; Procedures; Prosencephalon; Proteins; Receptor Gene; Regulation; Research Proposals; Role; Saline; Seizures; Sodium Butyrate; System; Testing; Therapeutic Effect; Transcription Repressor/Corepressor; Transcriptional Activation; Transcriptional Regulation; Transgenes; Transgenic Mice; Tranylcypromine; Vertebral column; Whole-Cell Recordings; World Health Organization; base; behavior test; brain tissue; chromatin immunoprecipitation; chromatin remodeling; conditioned fear; conventional therapy; disability; genome-wide; hippocampal pyramidal neuron; histone methyltransferase; histone modification; improved; in vivo; interest; mature animal; morris water maze; mouse model; neurotransmission; noradrenergic; novel; object recognition; postnatal; pre-clinical; preclinical study; promoter; receptor; receptor-mediated signaling; research study; response; tau Proteins; treatment strategy; treatment trial

DESCRIPTION (provided by applicant): Currently available antidepressant drugs typically modulate serotonergic, noradrenergic or dopaminergic neurotransmission and take 6-8 weeks to exert their effects. In addition, for each drug, up to 50-60% of patients show inadequate responses in treatment trials. Therefore, it will be important to explore novel antidepressant treatment strategies in pre-clinical studies. It has been suggested that chromatin remodeling mechanisms, including histone modification changes, play an important role for the neurobiology of depressive disorders. The foundations of this hypothesis are built on two observations in the pre-clinical model, (i) commonly used treatments, including antidepressant drugs and electroconvulsive seizures, induce dynamic changes in histone acetylation, and (ii) drugs that inhibit histone deacetylases (HDACs) exhibit antidepressant-like effects, or enhance the therapeutic effect of a conventional antidepressant such as fluoxetine. Based on these findings, it is assumed that drug induced hyperacetylation of histones and the resulting antidepressant effect is linked to "a loosening of chromatin structures and transcriptional activation". However, little is known about the neurological and behavioral phenotypes resulting from experimental manipulation of other histone modifications and histone modifying enzymes, particularly those defined by a genome-wide enrichment pattern that is highly divergent as compared to acetylation. To address these issues, we generated mice with a sustained increase in neuronal expression of Setdb1, encoding a developmentally regulated histone H3-lysine 9 specific histone methyltransferase associated with Sin3a-deacetylase, KAP-1 and NuRD transcriptional repressor complexes. Contrary to our original hypothesis, our preliminary data show that a sustained increase in Setdb1 levels in the forebrain is associated with antidepressant-like changes in behavioral despair and learned helplessness paradigms. Unexpectedly, Setdb1 occupancies in the genome were highly restricted overall, while enriched at several loci encoding glutamate receptor genes. This resulted in decreased levels of the NMDA receptor subunit Grin2b (NR2B) in prefrontal cortex and hippocampus. This finding is interesting because the non-specific NMDA receptor antagonist, ketamine, and the NR2B selective antagonist, CP101,606 elicit rapid antidepressant action in depressed subjects, including a subset of cases who had failed to respond to conventional treatments . The focus of this preclinical proposal is to explore the link between antidepressant-like phenotypes of Setdb1 transgenic mice, and the transcriptional regulation of NMDA receptor subunit Grin2b, and other gene expression changes, and to uncover novel treatment strategies for affective disorders. Our experiments utilize a comprehensive toolbox of in vivo and ex vivo approaches, including (a) multiple lines of genetically engineered mice to target the regulation of histone (H3-lysine 9) methylation in neuronal chromatin, (b) procedures to isolate neuronal chromatin from brain tissue, (c) chromatin immunoprecipitation followed by genome-wide profiling, (d) behavioral assays measuring despair and learned helplessness, anxiety, and learning and memory and (e) functional characterization of NMDA receptors in hippocampus and other brain regions implicated in the neurobiology of depression. This proposal will explore the antidepressant potential of Setdb1-regulated histone methylation, including the potential link to NMDA receptor-mediated signaling, thus offering the perspective of introducing a radically new treatment principle for a major psychiatric disorder. PUBLIC HEALTH RELEVANCE: According to estimates of the World Health Organization, depression could become the second most frequent cause of illness-induced disability by 2020. Currently available antidepressant drugs typically take up to 6-8 weeks to become effective. In addition, for each drug, up to 50-60% of patients show an unsatisfactory antidepressant response to the first drug, requiring switch of medication and other measures. Therefore, it will be very important to explore novel and hitherto unexplored antidepressant treatment strategies in the laboratory. Our research proposal will test the antidepressant potential of enzymes (proteins) that chemically modify histones (which function as the protein "backbone" of chromosomal material). To achieve this, we will change the activity and expression of one of these enzymes, known as "Setdb1" , in genetically engineered mice. Our preliminary data suggest that this approach will explore in this preclinical model a radically new treatment avenue for a major psychiatric disorder, by which a chromatin modifying enzyme (Setdb1) preferentially targets genes that encode certain type of nerve cell receptors (also known as "NMDA receptor"). Then, indirectly, the chromatin changes brought about by Setdb1 result in certain adaptations in the communication between nerve cells, ultimately resulting in an antidepressant-like effect.

描述（由申请人提供）：目前可用的抗抑郁药通常调节血清素能，去甲肾上腺素能或多巴胺能神经传递，并需要6-8周才能发挥作用。此外，对于每种药物，多达50-60％的患者在治疗试验中的反应不足。因此，在临床前研究中探索新颖的抗抑郁药治疗策略将很重要。有人提出，包括组蛋白修饰的变化在内的染色质重塑机制对于抑郁症的神经生物学起着重要作用。该假设的基础建立在临床前模型中的两个观察基础上，（i）常用的治疗方法，包括抗抑郁药和电驱动性癫痫发作，诱导组蛋白乙酰化的动态变化，以及（ii）抑制了这种抗性的抗态度，或者是抗抗性的，或者抑制了抗抗性的效应，或者是抑制了抗抗抑素的效应，或者是一种效果的效果，效果效应效果效应效果效果，效应效果效应效果效果，效果效应效果效应效果效应，效果效果效果效果效应效果效应效果效应效果效果，效果效果效应效果效应效果效果，呈现效果效应的效果效果效果。作为氟西汀。基于这些发现，假定药物诱导的组蛋白的高乙酰化和所得的抗抑郁作用与“染色质结构的松动和转录激活”有关。然而，关于其他组蛋白修饰和修饰酶的组蛋白的实验操纵引起的神经和行为表型知之甚少，尤其是由基因组富集模式定义的酶，与乙酰化相比，这种酶高度分歧。为了解决这些问题，我们生成了SETDB1神经元表达的持续增加的小鼠，编码了发育调节的组蛋白H3-赖氨酸9特异性组蛋白甲基转移酶与SIN3A-二乙酰基酶，KAP-1和NURD转录抑制剂复合物相关的组蛋白甲基转移酶。与我们最初的假设相反，我们的初步数据表明，前脑中的setDB1水平持续增加与行为绝望的抗抑郁样变化和学习的无助性范式有关。出乎意料的是，基因组中的SETDB1占用总体高度限制，同时在编码谷氨酸受体基因的几个基因座富集。这导致前额叶皮层和海马中NMDA受体亚基Grin2b（NR2B）的水平降低。这一发现很有趣，因为非特异性NMDA受体拮抗剂氯胺酮和NR2B选择性拮抗剂CP101,606引起对抑郁受试者的快速抗抑郁作用，包括未能对常规治疗反应的病例的一部分。该临床前建议的重点是探索setDB1转基因小鼠的抗抑郁样表型与NMDA受体亚基Grin2b的转录调控与其他基因表达变化之间的联系，并揭示了情感障碍的新型治疗策略。我们的实验利用体内和体内方法的全面工具箱，包括（a）多种遗传工程小鼠的靶向组蛋白（H3-赖氨酸9）在神经元染色质素中的调节（H3-赖氨酸9）甲基化，（b）在脑组织中脱离神经元的Chromativition（c）Chromecipition（c）Chromepition（c）Chromepition（c）Chromepition（c）Chromepition（c）Chromepition（C）绝望和学习的无助，焦虑，学习和记忆以及（e）与抑郁症神经生物学有关的海马和其他大脑区域中NMDA受体的功能表征。该提案将探索SETDB1调节的组蛋白甲基化的抗抑郁药潜力，包括与NMDA受体介导的信号传导的潜在联系，从而提供了引入大型精神病障碍的彻底新治疗原理的观点。 公共卫生相关性：根据世界卫生组织的估计，到2020年，抑郁症可能成为疾病引起的残疾的第二常见原因。目前可用的抗抑郁药通常需要长达6-8周才能有效。此外，对于每种药物，高达50-60％的患者对第一种药物的抗抑郁反应不令人满意，需要改用药物和其他措施。因此，探索实验室中的新颖和迄今未开发的抗抑郁治疗策略将非常重要。我们的研究建议将测试化学修饰组蛋白（蛋白质的蛋白质）（蛋白质）的抗抑郁潜力（蛋白质起作用（染色体材料的蛋白质“骨架”）。为此，我们将在基因工程小鼠中更改这些酶之一，称为“ setDB1”的活性和表达。我们的初步数据表明，这种方法将在这种临床前模型中探索一种针对主要的精神疾病的根本新的治疗途径，通过该疾病，染色质修饰酶（SETDB1）优先针对编码某些类型的神经细胞受体（也称为“ NMDA受体”）的基因。然后，间接地，由setDB1带来的染色质变化会导致神经细胞之间的通信某些适应，最终导致抗抑郁药样效应。