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Epilepsy and dendritic excitability

癫痫和树突状兴奋性

基本信息

批准号：
9890005
负责人：
NICHOLAS P POOLOS
金额：
$ 33.8万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-07-01 至 2023-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9890005
关键词：
Acute Address Affect Animal Model Antiepileptic Agents Brain Brain region Child Chronic Chronic Phase Collaborations Data Data Set Dendrites Development Developmental Delay Disorders Doctor of Philosophy Dominant-Negative Mutation Down-Regulation Electrophysiology (science)Epilepsy Epileptogenesis Event Fever Functional disorder Gene Mutation Genes Genetic Genetic Transcription Goals HCN1 channel HCN1 gene Hippocampus (Brain)Hour Human Human Genetics In Vitro Inherited Intellectual functioning disability Ion Channel Ion Channel Gating Laboratories Life Light Link Mass Spectrum Analysis Measures Mediating Membrane Modeling Molecular Mutation Neocortex Neuroglia Neurons Pathogenesis Patients Pharmaceutical Preparations Phosphorylation Population Process Protein Kinase C Rest Seizures Signal Transduction Status Epilepticus Surface Syndrome Techniques Testing Thalamic structure Time Tissues Transfection Universities Viral Washington Work biophysical properties cohort cyclic-nucleotide gated ion channels disability dravet syndrome epileptic encephalopathies experimental study gain of function hippocampal pyramidal neuron in vivo lamotrigine mRNA Expression mutant nervous system disorder novel protocadherin 19 public health relevance screening targeted treatment trafficking voltage gated channel

项目摘要

DESCRIPTION (provided by applicant): Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are voltage-gated ion channels that modulate excitability in several brain regions involved in the pathogenesis of epilepsy, including the hippocampus, neocortex, and thalamus. Accumulated evidence shows that downregulation of Ih, the current generated by HCN channels, causes neuronal hyperexcitability, and that genetic deletion of HCN1 channels, the main cortical and hippocampal subtype, accelerates the rate of epileptogenesis in acquired epilepsy models. More recent evidence shows that mutations in HCN1 underlie early life epileptic encephalopathy in some children with severe epilepsy and developmental delay. Thus HCN1 channelopathy occurs in both human genetic epilepsy and animal models of acquired epilepsy. In recent work from our laboratory, epilepsy induced by chemoconvulsant-induced status epilepticus (SE) was associated with loss of HCN1 channel expression that began within 1 hour post-SE, and persisted into chronic epilepsy. HCN1 channels were acutely internalized from the surface membrane of hippocampal pyramidal dendrites within the first hour following SE, well before the onset several days later of transcriptional downregulation of HCN1 mRNA expression. We now show for the first time that HCN1 channel surface expression is governed in a bidirectional fashion by protein kinase C (PKC) activity, with increased phosphorylation of HCN1 by PKC leading to decreased HCN1 surface expression. New preliminary data using mass spectrometry techniques show that HCN1 channels are minimally phosphorylated at rest, but undergo increased phosphorylation at S867 and S868 residues, which are also phosphorylated in naive tissue under conditions of PKC activation. These data suggest that the earliest manifestation of HCN1 channels dysfunction during epileptogenesis is PKC-mediated loss of surface expression and concomitant loss of HCN1-mediated current (Ih). Our goal in this R01 renewal application is to further understand the mechanisms of HCN1 channel dysfunction during the development of epilepsy. We propose to further study the phosphorylation signaling mechanisms underlying acute changes in HCN1 membrane trafficking after SE; determine whether these early events contribute to or initiate chronic HCN1 channelopathy; and characterize the effects of human HCN1 mutations on HCN1 channel biophysical properties. To do so, we will use state-of-the-art techniques including: mass spectrometry; viral transduction of mutant HCN1 channel expression in vivo; cellular electrophysiology in the dendrites of CA1 hippocampal pyramidal neurons; and analysis of a novel dataset of HCN1 mutations in a cohort of 800 children affected with epileptic encephalopathy of unknown cause.

描述（由申请人提供）：超极化激活的环核苷酸门控（HCN）通道是电压门控离子通道，可调节参与癫痫发病机制的多个大脑区域的兴奋性，包括海马体、新皮质和丘脑。积累的证据表明，HCN 通道产生的电流 Ih 的下调会导致神经元过度兴奋，而 HCN1 通道（主要皮质和海马亚型）的基因缺失会加速获得性癫痫模型中的癫痫发生率。最近的证据表明，HCN1 突变是一些患有严重癫痫和发育迟缓的儿童早期癫痫性脑病的基础。因此，HCN1 通道病发生在人类遗传性癫痫和获得性癫痫的动物模型中。在我们实验室最近的研究中，化学惊厥诱发的癫痫持续状态 (SE) 引起的癫痫与 SE 后 1 小时内开始的 HCN1 通道表达丧失相关，并持续发展为慢性癫痫。在 SE 后的第一个小时内，HCN1 通道从海马锥体树突的表面膜急剧内化，远早于几天后 HCN1 mRNA 表达转录下调的开始。我们现在首次表明，HCN1 通道表面表达受到蛋白激酶 C (PKC) 活性的双向控制，PKC 对 HCN1 的磷酸化增加导致 HCN1 表面表达减少。使用质谱技术的新初步数据表明，HCN1 通道在静止时磷酸化程度最低，但在 S867 和 S868 残基处磷酸化增加，在 PKC 激活条件下，这些残基在初始组织中也会磷酸化。这些数据表明，癫痫发生过程中 HCN1 通道功能障碍的最早表现是 PKC 介导的表面表达丧失以及伴随的 HCN1 介导的电流 (Ih) 丧失。我们在 R01 更新应用中的目标是进一步了解癫痫发展过程中 HCN1 通道功能障碍的机制。我们建议进一步研究 SE 后 HCN1 膜运输急性变化背后的磷酸化信号机制；确定这些早期事件是否导致或引发慢性 HCN1 通道病变；并表征人类 HCN1 突变对 HCN1 通道生物物理特性的影响。为此，我们将使用最先进的技术，包括：质谱分析；体内突变HCN1通道表达的病毒转导； CA1 海马锥体神经元树突的细胞电生理学；对 800 名不明原因癫痫性脑病儿童的 HCN1 突变新数据集进行分析。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Dephosphorylation proves detrimental to GABAergic inhibition.

去磷酸化被证明对 GABA 能抑制有害。

DOI：
10.5698/1535-7511-12.1.22
发表时间：
2012
期刊：
Epilepsy currents
影响因子：
3.6
作者：
Poolos,NicholasP
通讯作者：
Poolos,NicholasP

HCN Channel Phosphorylation Sites Mapped by Mass Spectrometry in Human Epilepsy Patients and in an Animal Model of Temporal Lobe Epilepsy.

DOI：
10.1016/j.neuroscience.2021.01.038
发表时间：
2021-04-15
期刊：
Neuroscience
影响因子：
3.3
作者：
Concepcion FA;Khan MN;Ju Wang JD;Wei AD;Ojemann JG;Ko AL;Shi Y;Eng JK;Ramirez JM;Poolos NP
通讯作者：
Poolos NP

Antiepileptic action of c-Jun N-terminal kinase (JNK) inhibition in an animal model of temporal lobe epilepsy.

DOI：
10.1016/j.neuroscience.2017.02.024
发表时间：
2017-05-04
期刊：
Neuroscience
影响因子：
3.3
作者：
Tai TY;Warner LN;Jones TD;Jung S;Concepcion FA;Skyrud DW;Fender J;Liu Y;Williams AD;Neumaier JF;D'Ambrosio R;Poolos NP
通讯作者：
Poolos NP

Genetic loss of HCN1 channels is exciting, but is it epileptic?

HCN1 通道的遗传缺失令人兴奋，但它会导致癫痫吗？

DOI：
10.1111/j.1535-7511.2009.01352.x
发表时间：
2010
期刊：
Epilepsy currents
影响因子：
3.6
作者：
Poolos,NicholasP
通讯作者：
Poolos,NicholasP

Rapid loss of dendritic HCN channel expression in hippocampal pyramidal neurons following status epilepticus.

DOI：
10.1523/jneurosci.1148-11.2011
发表时间：
2011-10-05
期刊：
The Journal of neuroscience : the official journal of the Society for Neuroscience
影响因子：
0
作者：
Jung S;Warner LN;Pitsch J;Becker AJ;Poolos NP
通讯作者：
Poolos NP