Epigenetic Markings in Developing and Diseased Prefrontal Neurons

描述（由申请人提供）：精神分裂症的定义是对绝大多数受影响的个体缺乏直接的遗传原因。前额叶皮层（PFC）和其他大脑区域被认为经常出现在精神分裂症患者身上，这反映在它的功能低下和多种基因表达失调上。潜在的分子机制尚不清楚，但有证据表明，PFC的长期成熟，延伸到甚至超过生命的第二个十年，对正常的人类发育和精神分裂症的神经生物学起着至关重要的作用。最近，我们首次提出证据表明，在整个产前和产后发育过程中，表观遗传标记的一个子集，包括基因启动子位点的三甲基化组蛋白h3 -赖氨酸4，参与了PFC染色质的动态调节，并且可能在一些精神分裂症患者中发生改变。这项挑战拨款提案已经“准备就绪”，既可以创造新的就业机会，也可以保留现有的就业机会。具体来说，我们将结合神经科学领域两种最具创新性的方法，因为它与表观遗传学有关，通过选择性地对神经元染色质进行分类，然后对免疫沉淀进行大规模平行测序（ChIP-seq），以深入了解前额叶神经元的表观基因组景观。我们将分析PFC神经元中与活性启动子（三甲基- h3k4）或转录（三甲基- h3k36）相关的组蛋白甲基化标记的发育和疾病相关变化。此外，我们将在条件突变小鼠中研究候选组蛋白赖氨酸甲基转移酶Mll1（混合谱系白血病1）在正常和病变前额叶发育中的作用，通过在断奶PFC中选择性表达Cre重组酶，然后监测成年动物的行为和分子变化。这里提出的实验将在挑战基金的24个月奖励期内完成，将首次阐明人类PFC神经元的染色质是否在疾病中受到发育调节和改变。这个问题在全基因组水平上的答案将是至关重要的，以便找出染色质为基础的机制是否最终共同病理生理学的一部分，潜在的前额叶功能障碍在大部分被诊断为精神分裂症的受试者中。

DESCRIPTION (provided by applicant): Schizophrenia is defined by a lack of a straightforward genetic cause for a very large majority of affected individuals. The prefrontal cortex (PFC), among other brain regions, is thought to be frequently in subjects in schizophrenia, as reflected by its functional hypoactivity and dysregulated expression for a diverse set of genes. The underlying molecular mechanisms remain unknown but there is evidence that the prolonged maturation of the PFC, extending into or even beyond the second decade of life, plays a crucial role for normal human development and the neurobiology of schizophrenia. Recently, we presented the first evidence that a subset of epigenetic markings, including trimethylated histone H3-lysine 4 at sites of gene promoters, is involved in the dynamic regulation of PFC chromatin during throughout pre- and postnatal development, and may be altered in some cases with schizophrenia. This challenge grant proposal is "shovel ready" and create new jobs as well as retain existing ones. Specifically, we will combine two of the most innovative approaches in the field of neurosciences as it pertains to epigenetics, by selectively sorting neuronal chromatin followed by massively parallel sequencing of immunprecipitates (ChIP-seq) to obtain insight into the epigenomic landscape of prefrontal neurons. We will profile developmental and disease-related changes in histone methylation markings associated with active promoters (trimethyl-H3K4) or transcription (trimethyl-H3K36) selectively in PFC neurons. Furthermore, we will study in conditional mutant mice the role of a candidate histone lysine methyltransferase, Mll1 (mixed-lineage leukemia 1) for normal and diseased prefrontal development, by expressing Cre recombinase selectively in weanling PFC and then monitor behavioral and molecular alterations in the adult animal. The experiments proposed here, which are designed to be accomplished within the challenge grant's award period of 24 months, will clarify, for the first time, whether or not chromatin of human PFC neurons is developmentally regulated and altered in disease. The answer to this question on a genome-wide level will be critical in order to find out whether or not chromatin-based mechanisms are part of a final common pathophysiology underlying prefrontal dysfunction in the substantial portion of subjects diagnosed with schizophrenia. PUBLICH HEALTH RELEVANCE: For the majority of patients diagnosed with schizophrenia, no straightforward genetic cause has been identified. One of the important theories about schizophrenia implies that in some brain regions, such as the "prefrontal cortex", a number of genes are not switched on properly during normal development, as they are in healthy subjects. However, until now the molecular techniques to study these phenomena have been lacking. This challenge grant proposal is "shovel ready", will create new jobs and retain existing ones. It is also based on extremely innovative techniques that were recently developed in our laboratories. We were able, for the first time, to selectively isolate chromosomal materials and chromatin from the nerve cells of the human brain obtained postmortem, and study "epigenetic markings" (basically, chemical modifications that regulate gene expression and function without altering the genetic code) on a genome-wide level. In this proposal, we plan to examine epigenetic gene activation patterns during normal prefrontal cortex development and search for potential alterations in schizophrenia and in mutant mice designed to model the disease on a molecular level. This research should clarify whether or not epigenetic markings are dynamically regulated in human neuronal chromatin , and if major psychiatric diseases such as schizophrenia are associated with changes in the neuronal epigenome.