Endogenous neurosteroids constrain network activity and limit seizure susceptibility

内源性神经类固醇限制网络活动并限制癫痫发作的易感性

基本信息

批准号：
10170601
负责人：
Jamie Lynn Maguire
金额：
$ 45.38万
依托单位：
TUFTS UNIVERSITY BOSTON
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-04-15 至 2023-09-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10170601
关键词：
5 Alpha-Reductase Inhibitor Acute Allopregnanolone Anticonvulsants Brain Brain region Cholesterol Chronic Development Electroencephalography Enzymes Epilepsy Epileptogenesis Finasteride Frequencies Glial Fibrillary Acidic Protein Hippocampus (Brain)Internal Ribosome Entry Site Interneurons Kainic Acid Knock-out Knowledge LoxP-flanked allele Measurement Measures Mediating Mus Neuroglia Neurons Output Oxidoreductase Patients Pattern Perforant Pathway Pharmacology Predisposition Process Recurrence Rodent Role Seizures Slice Status Epilepticus Temporal Lobe Epilepsy Testing Visualization calmodulin-dependent protein kinase II cell type extracellular knock-down mouse model neuronal excitability neurosteroids novel positive allosteric modulator pre-clinical receptor response steroid hormone metabolism tetrahydrodeoxycorticosterone tool

项目摘要

Project Summary There is extensive preclinical evidence for anticonvulsant effects of neuroactive steroids, which are thought to be mediated through their actions as positive allosteric modulators (PAMs) on GABAA receptors (GABAARs). These studies have relied on the administration of exogenous neuroactive steroids, although, neurosteroids can also be synthesized in the brain. However, we know very little about the function of endogenous neurosteroids due to the lack of tools necessary to investigate their function. The rate-limiting enzymes involved in neurosteroid synthesis, 5α-reductase 1 or 2, are expressed in the hippocampus and given their actions as PAMs at GABAARs, they are well-suited to constrain network excitability in this region. To investigate the function of endogenous neurosteroids, we generated novel mouse models (floxed Srd5a1- IRES-GFP and floxed Srd5a2-IRES-tdTomato) enabling visualization and quantification of changes in the expression of these enzymes associated as well as the ability to knockout these enzymes in a cell type- and brain region-specific manner. Here we propose to utilize these novel tools to test the hypothesis that endogenous neurosteroids constrain neuronal excitability and that deficits in 5α-reductase 1 and 2 expression in the hippocampus contributes to seizure susceptibility. We will determine whether 5α-reductase 1 and/or 2 expression is altered in chronically epileptic mice (Specific Aim 1) and if loss of 5α-reductase 1 and/or 2 expression in the hippocampus increases network excitability and acute seizure susceptibility (Specific Aim 2) or increases seizure frequency in chronically epileptic mice (Specific Aim 3).

项目摘要有广泛的临床前证明神经活性类固醇的抗惊厥作用，这是可以认为的通过他们作为GABAA接收器的阳性变构调节剂（PAM）的动作进行调解（加巴人）。这些研究对外源性神经活性类固醇的给药放松，尽管神经类固醇也可以在大脑中合成。但是，我们对由于缺乏研究其功能所需的工具，内源性神经素。限制速率在海马中表达参与神经蛋白酶合成的5α-还原酶1或2的酶，并给定他们在Gabaars作为PAM的行动非常适合限制该地区的网络兴奋性。到研究内源性神经素的功能，我们产生了新型的小鼠模型（Floxed Srd5a1-- IRES-GFP和Floxed Srd5A2-IRES-TDOMATO）可视化和量化变化这些酶的表达以及在细胞类型中敲除这些酶的能力大脑区域特异性的方式。在这里，我们建议利用这些新颖的工具来检验以下假设内源性神经类固醇限制了神经元的刺激性，并在5α-还原酶1和2表达中定义在海马中，有助于癫痫发作。我们将确定5α-还原酶1和/或2是否在慢性癫痫小鼠中的表达改变（特定的目标1），如果5α-还原酶1和/或2的丧失海马中的表达增加了网络兴奋性和急性癫痫敏感性（特定目标2）或增加慢性癫痫小鼠的癫痫发作频率（特定目标3）。