Brain Aromatase in Neurological Function and Disease

 描述(申请人提供)：最近的研究表明，前脑，特别是海马体，在男性和女性中都表现出高表达芳香酶(17？雌二醇(E2)合成酶)，并具有显著的雌二醇合成能力。在基础状态下，芳香酶在神经元中高表达，而在脑损伤后，芳香酶在反应性星形胶质细胞中高表达。目前，局部来源的E2在前脑中的作用和功能还知之甚少。这项建议的目的是阐明脑源性E2在生理和病理情况下的作用。我们的中心假设是，局部E2作为神经调节剂，调节大脑的可塑性和功能，并帮助保护和修复损伤后的大脑。我们将利用选择性敲除前脑神经元(FBN-Arko-/-)或星形胶质细胞(AS-Arko-/-)芳香酶表达的新型小鼠模型以及双重神经元/星形胶质细胞芳香酶基因敲除(DB-Arko-/-)小鼠模型来验证这一假设。目的1确定局部E2在非损伤脑内调节突触可塑性、神经元通讯和行为方面的作用。我们将确定前脑神经元和/或星形胶质细胞特异性E2的缺失是否会影响海马区突触的可塑性、神经反射、运动功能活动、感觉运动门控、焦虑、抑郁行为、背景恐惧和认知功能。目标2将确定局部E2在调节受损大脑中的神经炎症、神经保护和修复中的作用。我们将确定前脑神经元和/或星形胶质细胞特异性芳香酶的缺失是否会影响缺血诱导的神经元丢失、神经发生、神经胶质增生、神经炎症、可塑性和功能结果。目的3将阐明调节局部E2在大脑中的作用和控制的分子机制。我们将确定丢失前脑神经元和/或星形胶质细胞特异性的E2是否会影响膜启动的信号通路的激活，这些信号通路促进神经营养和生存效应(ERK、AKT、CREB)或促死亡和促炎效应(JNK/p38MAPK)-已知受核外雌激素受体(ER)调节的关键信号通路。在基因组水平上，RNA-Seq将被用来描述WT和KO小鼠前脑的基因表达差异。此外，还将研究局部E2在控制主要神经营养因子BDNF中的潜在关键作用。我们还将确定核外ER激活剂“拯救”在ARKO-/-小鼠中观察到的分子和功能表型的能力。最后，还将研究促炎细胞因子和转录因子C/EBP？在控制GCI后局部E2诱导中的作用。这项拟议的研究是创新的，因为利用了新的小鼠模型，该模型将定义脑源性E2在大脑中的作用。这些研究将对该领域产生重大影响，阐明脑源性E2的作用、机制和控制，可能为该领域带来新的想法和新的方向，并产生潜在的神经疾病新疗法。

 DESCRIPTION (provided by applicant): Recent work has shown that the forebrain, in particular the hippocampus, exhibits high expression of aromatase (the 17ß-estradiol (E2) synthesis enzyme) in both males and females, and has significant E2- generating capacity. Under basal conditions, aromatase is highly expressed in neurons, whereas after brain injury, aromatase becomes highly expressed in reactive astrocytes. Currently, the roles and functions of local-derived E2 in the forebrain are poorly understood. The objective of this proposal is to elucidate the role of brain-derived E2 in both physiological and pathological situations. Our central hypothesis is that local E2 acts as a neuromodulator to regulate brain plasticity and function, and to help protect and repair the brain following injury. We will test the hypothesis utilizing novel mouse models with selective knockout of aromatase expression in forebrain neurons (FBN-ARKO-/-) or in astrocytes (AS-ARKO-/-) and by using a double neuron/astrocyte aromatase knockout (DB-ARKO-/-) mouse model. Aim 1 will determine the role of local E2 in regulating synaptic plasticity, neuronal communication, and behavior in the non-injured brain. We will determine whether loss of forebrain neuronal and/or astrocyte-specific E2 affects hippocampal synaptic plasticity, neurological reflexes, motor function activity, sensorimotor gating, anxiety, depressive- behavior, contextual fear, and cognitive function. Aim 2 will define the role of local E2 in modulating neuroinflammation, neuroprotection and repair in the injured brain. We will determine whether loss of forebrain neuronal and/or astrocyte-specific aromatase affects ischemia-induced neuronal loss, neurogenesis, gliosis, neuroinflammation, plasticity, and functional outcome. Aim 3 will elucidate the molecular mechanisms that mediate the actions and control of local E2 in the brain. We will determine whether loss of forebrain neuronal and/or astrocyte-specific E2 affects activation of membrane-initiated signaling pathways that promote neurotrophic and prosurvival effects (ERK, AKT, CREB), or prodeath and proinflammatory effects (JNK/P38MAPK) - key signaling pathways that are known to be regulated by extranuclear estrogen receptors (ER). At the genomic level, RNA-Seq will be used to profile gene expression differences in WT vs. KO mouse forebrains. Additionally, a potential key role of local E2 in control of the major neurotrophic factor, BDNF will also be examined. We will also determine the ability of extranuclear ER activators to "rescue" molecular and functional phenotypes observed in the ARKO-/- mice. Finally, the role of pro-inflammatory cytokines and the transcription factor C/EBPß in the control of local E2 induction after GCI will also be examined. The proposed research is innovative due to utilization of novel mouse models that will define the role of brain-derived E2 in the brain. The studies will have a significant impact upon the field by elucidating the roles, mechanisms and control of brain-derived E2, which could lead to new ideas and new directions for the field, and to generation of potential new therapies for neurological disorders.