Progesterone Receptors and Seizure Susceptibility

黄体酮受体和癫痫易感性

• 批准号: 7671859
• 负责人: Doodipala Samba Reddy
• 金额: $ 30.88万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7671859
• 关键词: Address; Affect; Allopregnanolone; Anabolism; Animal Model; Anticonvulsants; Antisense Oligonucleotides; Binding; Biological Models; Brain region; Chemosensitization; Condition; DNA; Data; Development; Disease; Electrophysiology (science); Elevation; Endocrine; Epilepsy; Epileptogenesis; Equilibrium; Event; Exhibits; Finasteride; Functional disorder; GABA Receptor; Gene Expression; Gene Targeting; Genes; Genetic Models; Genomics; Goals; Hippocampus (Brain); Hormones; Intervention; Kindling (Neurology); Knock-out; Knockout Mice; Lead; Link; Mediating; Menarche; Menopause; Messenger RNA; Methodology; Modeling; Molecular; Molecular Genetics; Molecular Mechanisms of Action; Mus; Neurons; Nuclear; Outcome; Oxidoreductase; Pathway interactions; Physiological; Play; Polymerase Chain Reaction; Predisposition; Pregnancy; Principal Investigator; Progesterone; Progesterone Receptors; Property; Proteins; RU-486; Rate; Receptor Inhibition; Regulation; Research Personnel; Resistance; Reverse Transcriptase Polymerase Chain Reaction; Role; Seizures; Study Section; Techniques; Testing; Time; Transgenic Organisms; United States; Western Blotting; Wild Type Mouse; Withdrawal; Woman; dentate gyrus; granule cell; improved; innovation; knock-down; mouse model; non-genomic; novel; patch clamp; perimenstrual; postsynaptic; programs; promoter; protein expression; receptor; receptor binding; receptor expression; receptor function; relating to nervous system; research study; response; transcription factor; transmission process

DESCRIPTION (provided by applicant): Progesterone (P) plays a key role in the pathophysiology of "catamenial epilepsy", a menstrual cyclerelated seizure disorder that affects many women with epilepsy. While P's endocrine actions are mediated by the progesterone receptor (PR), P's molecular mechanism of action in seizure activity is not clearly understood. P modulates seizure activity partly through conversion to allopregnanolone, which enhances GABAA receptor function. Recently, we have made the novel discovery that PRs play a key role in seizure susceptibility. Our preliminary results underscore that PR knockout (PRKO) mice exhibit elevated seizure threshold and resistance to kindling epileptogenesis, suggesting that PRs mediate seizure susceptibility. In this application, we propose to elucidate the molecular mechanisms whereby PRs increase seizure susceptibility in the hippocampus, utilizing genetic, molecular and electrophysiological approaches. We hypothesize that progesterone's actions on seizure activity are due in part to PR regulation of hippocampal GABA^ receptor subunit expression and function that results in reduced inhibition and thereby seizure susceptibility. PR-mediated "subunit switching" leading to alterations of GABAA receptor subunit composition and functional properties are the molecular mechanism by which P controls seizure susceptibility. We propose to test this hypothesis critically utilizing 3 model systems that are well established in our lab: 1) PRKO transgenic mouse model; 2) Antisense PR inhibition in wild-type mice; and 3) RU-486 blockade of PR function in wild-type mice. The Specific Aims of this proposal are: 1) to determine whether PRs increase seizure susceptibility using the kindling model of epilepsy; and 2) to determine whether PRs are involved in P induced alterations in GABAA receptor subunit expression and channel function. Aim 1 will examine the rate of hippocampus kindling in WT and PRKO mice, with and without P and/or finasteride treatment, as an indicator of epileptogenesis. Aim 2 will assess mRNA (real-time PCR) and protein levels (Westerns blots) of GABAA receptor subunits in hippocampal subfields in WT and PRKO mice treated with P, P+finasteride, and 24 hrs after neurosteroid withdrawal. We will verify the functional importance of P induced changes in GABAA receptor subunit expression by recording GABA-gated CI" currents in acutely isolated hippocampal neurons using patch-clamp electrophysiology. Significance. The proposed study will provide novel information on the P mechanisms governing regulation of seizure susceptibility, which could lead to improved understanding of catamenial epilepsy. Relevance. Women with catamenial epilepsy have seizures clustered around their monthly cycle. However, currently the pathophysiology of this condition is not fully understood. The studies proposed in this application will help better understand the disease mechanism and thereby allow development of specific therapies for catamenial epilepsy and other conditions associated with fluctuations in progesterone levels.

描述（由申请人提供）：黄体酮 (P) 在“经期癫痫”的病理生理学中发挥着关键作用，“经期癫痫”是一种与月经周期相关的癫痫疾病，影响许多患有癫痫的女性。虽然 P 的内分泌作用是由孕激素受体 (PR) 介导的，但 P 在癫痫发作活动中的分子作用机制尚不清楚。 P 部分通过转化为四氢孕酮来调节癫痫发作活动，从而增强 GABAA 受体功能。最近，我们有了新的发现，即 PR 在癫痫易感性中起着关键作用。我们的初步结果强调，PR 敲除 (PRKO) 小鼠表现出较高的癫痫阈值和对引发癫痫发生的抵抗力，表明 PR 介导癫痫易感性。在此应用中，我们建议利用遗传、分子和电生理学方法阐明 PR 增加海马癫痫易感性的分子机制。我们假设黄体酮对癫痫发作活动的作用部分是由于PR对海马GABA 受体亚基表达和功能的调节，导致抑制减少，从而癫痫易感性降低。 PR 介导的“亚基转换”导致 GABAA 受体亚基组成和功能特性的改变，是 P 控制癫痫易感性的分子机制。我们建议利用我们实验室成熟的 3 个模型系统来批判性地检验这一假设：1）PRKO 转基因小鼠模型； 2) 野生型小鼠中的反义PR抑制； 3) RU-486 阻断野生型小鼠的 PR 功能。该提案的具体目标是： 1) 使用癫痫点燃模型确定 PR 是否会增加癫痫发作的易感性； 2) 确定 PR 是否参与 P 诱导的 GABAA 受体亚基表达和通道功能的改变。目标 1 将检查 WT 和 PRKO 小鼠中海马点燃率，无论是否接受 P 和/或非那雄胺治疗，作为癫痫发生的指标。目标 2 将评估接受 P、P+非那雄胺治疗以及神经类固醇停药后 24 小时的 WT 和 PRKO 小鼠海马亚区 GABAA 受体亚基的 mRNA（实时 PCR）和蛋白质水平（蛋白质印迹）。我们将通过使用膜片钳电生理学记录急性分离的海马神经元中的 GABA 门控 CI 电流，验证 P 诱导 GABAA 受体亚基表达变化的功能重要性。意义。本研究将为控制 GABAA 受体亚基表达的 P 机制提供新的信息。癫痫易感性，这可能会提高对经期癫痫的了解。然而，目前，经期癫痫的病理生理学仍集中在女性的月经周期上。本申请中提出的研究将有助于更好地了解这种疾病的机制，从而开发针对月经期癫痫和与孕酮水平波动相关的其他疾病的特定疗法。