Shaw Potassium Channels

Shaw 钾通道
  • 文章类型: Journal Article
    背景:由于阿尔茨海默病(AD)的异质性,其致病机制尚未完全阐明。证据表明代谢在AD的病理生理学中起重要作用。在这里,我们确定了代谢相关的AD亚型和特征基因.
    方法:AD数据集从基因表达综合数据库获得,代谢相关基因从先前发表的汇编中下载。进行共有聚类以鉴定AD子类。临床特点,与代谢特征的相关性,评估AD亚类的免疫浸润。使用加权相关网络分析(WGCNA)筛选特征基因,并通过基因本体论和京都基因和基因组途径分析进行处理。此外,使用三种机器学习算法来缩小特征基因的选择范围。最后,我们使用AD数据集和定量逆转录聚合酶链反应(qRT-PCR)分析鉴定了特征基因的诊断价值和表达.
    结果:确定了三个AD亚类,即代谢相关(MC)A(MCA),MCB,和MCC子类。MCA包含与高AD进展相关的特征,并且与其他两个亚类相比可能代表高风险亚类。MCA表现出与糖酵解相关的基因的高表达,果糖,和半乳糖代谢,而与柠檬酸盐循环和丙酮酸代谢相关的基因下调,并与高免疫浸润相关。相反,MCB与柠檬酸盐周期基因相关,并表现出免疫检查点基因的表达升高。使用WGCNA,101个代谢基因被鉴定为表现出与不良AD进展的最强关联。最后,机器学习算法的应用使我们能够成功识别八个特征基因,用于开发可以为AD患者带来明显临床益处的列线图模型。如AD数据集和qRT-PCR分析所示,这些基因与AD进展密切相关。
    结论:代谢功能障碍与AD相关。基于代谢基因的AD假设分子亚类可能为开发AD的个体化治疗提供新的见解。与AD进展高度相关的特征基因包括GFAP,CYB5R3,DARS,KIAA0513,EZR,KCNC1、COLEC12和TST。
    Owing to the heterogeneity of Alzheimer\'s disease (AD), its pathogenic mechanisms are yet to be fully elucidated. Evidence suggests an important role of metabolism in the pathophysiology of AD. Herein, we identified the metabolism-related AD subtypes and feature genes.
    The AD datasets were obtained from the Gene Expression Omnibus database and the metabolism-relevant genes were downloaded from a previously published compilation. Consensus clustering was performed to identify the AD subclasses. The clinical characteristics, correlations with metabolic signatures, and immune infiltration of the AD subclasses were evaluated. Feature genes were screened using weighted correlation network analysis (WGCNA) and processed via Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses. Furthermore, three machine-learning algorithms were used to narrow down the selection of the feature genes. Finally, we identified the diagnostic value and expression of the feature genes using the AD dataset and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis.
    Three AD subclasses were identified, namely Metabolism Correlated (MC) A (MCA), MCB, and MCC subclasses. MCA contained signatures associated with high AD progression and may represent a high-risk subclass compared with the other two subclasses. MCA exhibited a high expression of genes related to glycolysis, fructose, and galactose metabolism, whereas genes associated with the citrate cycle and pyruvate metabolism were downregulated and associated with high immune infiltration. Conversely, MCB was associated with citrate cycle genes and exhibited elevated expression of immune checkpoint genes. Using WGCNA, 101 metabolic genes were identified to exhibit the strongest association with poor AD progression. Finally, the application of machine-learning algorithms enabled us to successfully identify eight feature genes, which were employed to develop a nomogram model that could bring distinct clinical benefits for patients with AD. As indicated by the AD datasets and qRT-PCR analysis, these genes were intimately associated with AD progression.
    Metabolic dysfunction is associated with AD. Hypothetical molecular subclasses of AD based on metabolic genes may provide new insights for developing individualized therapy for AD. The feature genes highly correlated with AD progression included GFAP, CYB5R3, DARS, KIAA0513, EZR, KCNC1, COLEC12, and TST.
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  • 文章类型: Journal Article
    KCNC2基因编码Kv3.2,它是电压门控钾通道亚家族的成员。对于皮质GABA能中间神经元中快速尖峰特性的产生至关重要。最近,发现KCNC2变异与无关个体的癫痫性脑病有关。这里,我们报道了一名患有发育性和癫痫性脑病(DEE)和运动发育迟缓的中国患者。全外显子组测序(WES)揭示了KCNC2基因NM_139137.4:c.1163T>C(p。Phe388Ser),随后的Sanger测序显示这是一个从头突变。通过重新分析一个中国家庭的WES数据,我们确定了一名DEE患者的KCNC2可能致病变异。我们的研究丰富了KCNC2基因的变异谱,促进了WES技术和数据再分析在癫痫诊断中的应用。
    The KCNC2 gene encodes Kv3.2, which is a member of the voltage-gated potassium channel subfamily. It is crucial for the generation of fast-spiking properties in cortical GABAergic interneurons. Recently, KCNC2 variations were found to be associated with epileptic encephalopathy in unrelated individuals. Here, we report a Chinese patient with developmental and epileptic encephalopathy (DEE) and motor development delay. Whole-exome sequencing (WES) revealed a novel heterozygous variant in the KCNC2 gene NM_139137.4:c.1163T>C (p.Phe388Ser), and subsequent Sanger sequencing showed that it was a de novo mutation. We identified the KCNC2 likely pathogenic variant in a DEE patient by reanalysis of WES data in a Chinese family. Our study enriched the variation spectrum of the KCNC2 gene and promoted the application of WES technology and data reanalysis in the diagnosis of epilepsy.
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  • 文章类型: Journal Article
    本研究的目的是通过网络药理学分析二甲双胍抗卵巢癌(OC)的潜在靶点。使用中药分子机制的生物信息学分析工具(BATMAN)预测二甲双胍的药效学目标,药店,PharmMapper,SwissTargetPrediction,和TargetNet数据库。R用于分析OC组织的基因表达,正常/邻近非癌组织,并在基因表达综合(GEO)和癌症基因组图谱(TCGA)+基因型-组织表达(GTEx)数据集中筛选差异表达基因(DEGs)。STRING11.0用于探索在OC中差异表达的二甲双胍靶基因的蛋白质-蛋白质相互作用(PPI)。使用Cytoscape3.8.0构建网络并筛选核心目标。此外,通过DAVID6.8数据库对二甲双胍和OC的常见靶标进行基因本体论(GO)注释和富集以及京都基因和基因组百科全书(KEGG)途径富集分析。从255个潜在的二甲双胍药效学靶标和10,463个与OC相关的基因的交集中,共鉴定出95个潜在的二甲双胍和OC的共同靶标。此外,从PPI网络中筛选出10个核心目标[例如,白细胞介素(IL)1B,KCNC1,ESR1,HTR2C,MAOB,GRIN2A,F2,GRIA2,APOE,PTPRC]。此外,GO富集分析显示,常见靶标主要与生物过程相关(即,对刺激或化学物质的反应,细胞过程,和跨膜运输),细胞成分(即,质膜,细胞连接,和细胞投影),和分子功能(即,绑定,渠道活动,跨膜转运蛋白活性,和信号受体活性)。此外,KEGG途径分析表明,常见靶标富集在代谢途径中.通过基于生物信息学的网络药理学分析,初步确定了二甲双胍抗OC的关键分子靶点和分子通路,提供基础,并为进一步的实验研究提供参考。
    The objective of this study was to analyze potential targets of metformin against ovarian cancer (OC) through network pharmacology. Pharmacodynamic targets of metformin were predicted using the Bioinformatics Analysis Tool for the molecular mechanism of traditional Chinese medicine (BATMAN), Drugbank, PharmMapper, SwissTargetPrediction, and TargetNet databases. R was utilized to analyze the gene expression of OC tissues, normal/adjacent noncancerous tissues, and screen differentially expressed genes (DEGs) in the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) + Genotype-Tissue Expression (GTEx) datasets. STRING 11.0 was utilized to explore the protein-protein interaction (PPI) of metformin target genes differentially expressed in OC. Cytoscape 3.8.0 was used to construct the network and screen the core targets. Additionally, gene ontology (GO) annotation and enrichment and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed for the common targets of metformin and OC through the DAVID 6.8 database. A total of 95 potential common targets of metformin and OC were identified from the intersection of 255 potential pharmacodynamic targets of metformin and 10,463 genes associated with OC. Furthermore, 10 core targets were screened from the PPI network [e.g., interleukin (IL) 1B, KCNC1, ESR1, HTR2C, MAOB, GRIN2A, F2, GRIA2, APOE, PTPRC]. In addition, it was shown in GO enrichment analysis that the common targets were mainly associated with biological processes (i.e., response to stimuli or chemical, cellular processes, and transmembrane transport), cellular components (i.e., plasma membrane, cell junction, and cell projection), and molecular functions (i.e., binding, channel activities, transmembrane transporter activity, and signaling receptor activities). Furthermore, it was indicated by KEGG pathway analysis that the common targets were enriched in metabolic pathways. The critical molecular targets and molecular pathways of metformin against OC were preliminarily determined by bioinformatics-based network pharmacology analysis, providing a basis, and reference for further experimental studies.
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  • 文章类型: Journal Article
    随着新一代测序技术的发展和应用,遗传性癫痫的病因诊断正在迅速变得更容易和更便宜。此外,基于基因诊断的精准治疗研究越来越多。钾离子通道家族中的众多基因构成了最大的离子通道家族:该家族分为不同的亚型。钾离子通道在神经元的电活动中起着至关重要的作用,并直接参与癫痫发作的机制。在中国,基因诊断的科学研究和遗传性癫痫精准治疗的研究进展迅速。已经确定了许多由钾通道基因突变引起的癫痫病例,已经发现了几种钾通道基因靶标和候选药物。本文就钾离子通道相关性遗传性癫痫的精准诊断和治疗研究进展作一简要综述,尤其是在中国进行的研究。在这里,我们回顾了近年来国内关于癫痫基因诊断的几个大型队列研究,总结了钾通道基因的比例。我们重点关注一些热点癫痫相关钾通道基因:KCNA1,KCNA2,KCNB1,KCNC1,KCND2,KCNQ2,KCNQ3,KCNMA1和KCNT1的治疗进展。
    With the development and application of next-generation sequencing technology, the aetiological diagnosis of genetic epilepsy is rapidly becoming easier and less expensive. Additionally, there is a growing body of research into precision therapy based on genetic diagnosis. The numerous genes in the potassium ion channel family constitute the largest family of ion channels: this family is divided into different subtypes. Potassium ion channels play a crucial role in the electrical activity of neurons and are directly involved in the mechanism of epileptic seizures. In China, scientific research on genetic diagnosis and studies of precision therapy for genetic epilepsy are progressing rapidly. Many cases of epilepsy caused by mutation of potassium channel genes have been identified, and several potassium channel gene targets and drug candidates have been discovered. The purpose of this review is to briefly summarize the progress of research on the precise diagnosis and treatment of potassium ion channel-related genetic epilepsy, especially the research conducted in China. Here in, we review several large cohort studies on the genetic diagnosis of epilepsy in China in recent years, summarized the proportion of potassium channel genes. We focus on the progress of precison therapy on some hot epilepsy related potassium channel genes: KCNA1, KCNA2, KCNB1, KCNC1, KCND2, KCNQ2, KCNQ3, KCNMA1, and KCNT1.
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  • 文章类型: Journal Article
    在慢性心力衰竭(CHF)状态下,过度的运动压迫反射(EPR)会导致过度的交感神经兴奋和运动不耐受。肌肉传入敏化有助于CHF中过度EPR的发生。然而,CHF中肌肉传入致敏的细胞机制尚不清楚.考虑到电压门控钾(Kv)通道关键调节传入神经元兴奋性,我们研究了Kv通道在介导CHF雄性大鼠致敏EPR中的潜在作用。实时逆转录聚合酶链反应(RT-PCR)和Western印迹实验表明,腰背根神经节(DRGs)中多个Kv通道亚型(Kv1.4,Kv3.4,Kv4.2和Kv4.3)的mRNA和蛋白表达均下调。与假模型大鼠相比,CHF大鼠。免疫荧光数据表明,与假手术大鼠相比,CHF大鼠中NF200阳性和IB4阳性腰椎DRG神经元的Kv通道染色显着降低。来自膜片钳实验的数据表明,总Kv电流,尤其是IA,与假手术大鼠相比,CHF大鼠的中型IB4阴性肌肉传入神经元(主要包含Aδ神经元的亚群)显着减少,表明肌肉传入Aδ神经元中Kv通道的潜在功能丧失。在体内实验中,腰椎DRG中Kv4.3的腺病毒过表达1周可减弱由肌肉静态收缩和被动拉伸引起的机械反射引起的过度EPR,而不会影响CHF大鼠对后肢动脉注射辣椒素的心血管反应。这些数据表明,DRG中的Kv通道功能障碍在介导CHF中过度的EPR和肌肉传入敏化中起关键作用。新的和注意本手稿的主要发现是DRGs中的电压门控钾(Kv)通道功能障碍在介导慢性心力衰竭(CHF)中过度的EPR和肌肉传入敏化中起关键作用。我们建议在DRG神经元中操纵Kv通道可以被认为是减少过度的交感神经兴奋和改善CHF中运动不耐受的潜在新方法。这最终可以促进生活质量的提高并降低死亡率。
    An exaggerated exercise pressor reflex (EPR) causes excessive sympathoexcitation and exercise intolerance during physical activity in the chronic heart failure (CHF) state. Muscle afferent sensitization contributes to the genesis of the exaggerated EPR in CHF. However, the cellular mechanisms underlying muscle afferent sensitization in CHF remain unclear. Considering that voltage-gated potassium (Kv) channels critically regulate afferent neuronal excitability, we examined the potential role of Kv channels in mediating the sensitized EPR in male rats with CHF. Real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting experiments demonstrate that both mRNA and protein expressions of multiple Kv channel isoforms (Kv1.4, Kv3.4, Kv4.2, and Kv4.3) were downregulated in lumbar dorsal root ganglions (DRGs) of CHF rats compared with sham rats. Immunofluorescence data demonstrate significant decreased Kv channel staining in both NF200-positive and IB4-positive lumbar DRG neurons in CHF rats compared with sham rats. Data from patch-clamp experiments demonstrate that the total Kv current, especially IA, was dramatically decreased in medium-sized IB4-negative muscle afferent neurons (a subpopulation containing mostly Aδ neurons) from CHF rats compared with sham rats, indicating a potential functional loss of Kv channels in muscle afferent Aδ neurons. In in vivo experiments, adenoviral overexpression of Kv4.3 in lumbar DRGs for 1 wk attenuated the exaggerated EPR induced by muscle static contraction and the mechanoreflex by passive stretch without affecting the blunted cardiovascular response to hindlimb arterial injection of capsaicin in CHF rats. These data suggest that Kv channel dysfunction in DRGs plays a critical role in mediating the exaggerated EPR and muscle afferent sensitization in CHF.NEW & NOTEWORTHY The primary finding of this manuscript is that voltage-gated potassium (Kv) channel dysfunction in DRGs plays a critical role in mediating the exaggerated EPR and muscle afferent sensitization in chronic heart failure (CHF). We propose that manipulation of Kv channels in DRG neurons could be considered as a potential new approach to reduce the exaggerated sympathoexcitation and to improve exercise intolerance in CHF, which can ultimately facilitate an improved quality of life and reduce mortality.
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  • 文章类型: Journal Article
    本研究的目的是探索和验证精原细胞瘤进展的潜在机制。从癌症基因组图谱数据库下载来自II/III期和I期精原细胞瘤标本的132个RNA-seq和156个甲基化位点的数据。使用|倍数变化|>2和错误发现率<0.05的初始过滤器来鉴定与差异甲基化位点基因相关的差异表达基因(DEG);通过生存分析,这些基因被认为是进一步研究的潜在候选基因。在精原细胞瘤人组织和三种精原细胞瘤细胞系中证实了钾电压门控通道亚家族C成员1(KCNC1)的表达。侵入性的,人睾丸肿瘤Ntera-2和正常人睾丸Hs1的增殖和凋亡能力。在异常KCNC1表达后评估Tes细胞系。KCNC1被鉴定为DEG,其中高甲基化抑制了其表达,并且与精原细胞瘤患者的总体生存率低相关。目前的结果表明,KCNC1与甲基化呈负相关。由于KCNC1在精原细胞瘤细胞中的异常表达,提示KCNC1可作为精原细胞瘤进展的诊断指标和治疗靶点.
    The aim of the present study was to explore and verify the potential mechanism of seminoma progression. Data on 132 RNA‑seq and 156 methylation sites from stage II/III and I seminoma specimens were downloaded from The Cancer Genome Atlas database. An initial filter of |fold‑change| >2 and false discovery rate <0.05 were used to identify differentially expressed genes (DEGs) which were associated with differential methylation site genes; these genes were considered potential candidates for further investigation by survival analysis. Potassium voltage‑gated channel subfamily C member 1 (KCNC1) expression was verified in seminoma human tissues and three seminoma cell lines. The invasive, proliferative and apoptotic abilities of the human testicular tumor Ntera‑2 and normal human testis Hs1.Tes cell lines were assessed following aberrant KCNC1 expression. KCNC1 was identified as a DEG, in which hypermethylation inhibited its expression and it was associated with poor overall survival in patients with seminoma. The present results demonstrated that KCNC1 is negatively correlated with methylation. Due to the abnormal expression of KCNC1 in seminoma cells, it was suggested that KCNC1 could be used as a diagnostic indicator and therapeutic target for the progression of seminoma.
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    文章类型: Journal Article
    This study aims to explore the regulatory mechanism of hypoxia-inducible factor HIF-1α on Kv3.4. Oral squamous cell carcinoma (OSCC) cell lines SCC3 and CAL27 were used in this study. Western blotting and qRT-PCR methods were used to detect Kv3.4 expression levels in OSCC and their adjacent tissues. The expression changes of Kv3.4 and HIF-1α in a hypoxic environment were detected in cell lines. The stable OSCC cell lines with knockouts of HIF-1α and Kv3.4 were constructed. Transwell and CCK-8 assays were used to detect changes in the invasion, migration and proliferation ability after transfection. Chromatin immunoprecipitation and luciferase reporter gene assays were used to determine the regulatory and binding sites of HIF-1α on Kv3.4. The expression level of Kv3.4 in oral cancer tissue was higher than normal oral epithelium\'s regular value. The expression level of HIF-1α and Kv3.4 increased under hypoxia. Knocking out HIF-1α and Kv3.4 could reduce the invasion, migration and proliferation of cells. A down regulation of HIF-1α will reduce the Kv3.4 expression level. Overexpressing Kv3.4 after knocking down HIF-1α partially restored the proliferation and invasion of cell lines. Therefore, HIF-1α regulates the invasion, migration and proliferation of oral cancer cells by regulating Kv3.4 expression.
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  • 文章类型: Journal Article
    Objective: To identify the pathogenic gene variants and clinical phenotype features of 26 children with progressive myoclonic epilepsy (PME). Methods: In this cross-sectional study, 26 PME children (11 boys and 15 girls) sent to neurological outpatient clinics and admitted to wards of the Department of Pediatrics, Peking University First Hospital were enrolled prospectively from January 2014 to October 2018. The pathogenic gene variants of PME children and their parents were identified by Sanger sequencing, next generation sequencing panels of epilepsy or trio-based whole exome sequencing and so on. The genotypes and phenotypes of the PME children were anaylzed. Results: The clinical features of 26 children include myoclonus, multiple types of seizures and progressive neurological regression. Their onset ages ranged from 3 months to 15 years. Several pathogenic gene variants were identified in the 15 patients, including TPP1 gene variantions in 3 patients; NEU1, GBA, TBC1D24 and KCNC1 gene variantions in 2 patients respectively; CLN6, MFSD8, ASAH1 and ATN1 gene variantions in 1 patient respectively. Several variants of uncertain significance were identified in 4 patients, including GOSR2 gene compound heterozygous variants in 2 patients, KCTD7 gene compound heterozygous variants in 1 patient, and compound heterozygous variants of an unreported TARS gene in 1 patient. No pathogenic gene variant was identified in 7 patients. In 15 children with the identified pathogenic gene variants, 5 patients were diagnosed with neuronal ceroid lipofuscinoses (NCL), 2 patients with sialidosis, 2 patients with neuronopathic Gaucher disease, 1 patient with dentatorubral-pallidoluysian atrophy (DRPLA), and 1 patient with spinal muscular atrophy-progressive myoclonic epilepsy (SMA-PME). Conclusions: PME include a group of diseases with genetic heterogeneity. Identification of the pathogenic gene variants of PME could help to predict the prognosis and guide the genetic counseling.
    目的: 总结进行性肌阵挛癫痫(PME)患儿的致病基因和临床表型特点。 方法: 采用横断面设计的方法,2014年1月至2018年10月前瞻性收集在北京大学第一医院儿科神经门诊及病房临床诊断为PME的患儿,共收集PME患儿26例,男11例、女15例。通过目的基因一代测序、靶向捕获二代测序癫痫基因检测包或家系全外显子组等方法,对患儿及其父母进行致病基因检测,并对患儿的基因型与表型特点进行分析。 结果: 26例PME患儿起病年龄为3月龄至15岁,临床特点包括肌阵挛、多种类型的癫痫发作和进行性神经功能倒退。明确致病基因的患儿15例,包括TPP1基因3例,NEU1、GBA、TBC1D24、KCNC1基因各2例,CLN6、MFSD8、ASAH1和ATN1基因各1例。4例患儿发现可能的致病基因,其中2例GOSR2基因复合杂合变异,1例KCTD7基因复合杂合变异,1例国际未报道的TARS基因复合杂合变异。7例患儿尚未明确致病基因。15例致病基因明确的患儿中,符合神经元蜡样质脂褐质沉积症(NCL)者5例,唾液酸沉积症、神经型戈谢病各2例,齿状核红核苍白球路易体萎缩症、脊肌萎缩症-进行性肌阵挛癫痫各1例。 结论: PME包括一组具有遗传异质性的神经遗传病,明确PME的致病基因对判断预后及遗传咨询具有重要意义。.
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  • 文章类型: Journal Article
    脆性X综合征(FXS)的特征是对感觉刺激过敏,包括环境的声音。我们比较了缺乏脆性X智力低下蛋白(FMRP)基因(Fmr1-/y)的小鼠体内记录的听觉脑干反应(ABR)与野生型动物。我们发现ABR波I,代表来自听觉神经的输入,在Fmr1-/y动物中减少,但只有在高声音水平。相比之下,波IV,这代表听觉脑干核的活动在所有声音水平上都得到增强,这表明FMRP的丢失改变了听觉信号的中央处理。听觉脑干梯形体内侧核中神经元的电流钳记录显示,与野生型动物的神经元相反,持续的去极化触发重复放电,而不是单一的动作电位。在电压钳记录中,在正电位下激活的K+电流(“高阈值”K+电流),这是高频点火所需的,主要由Kv3.1通道承载,在Fmr1-/y小鼠中升高,而在静息电位附近激活并抑制重复放电的K电流减少。因此,我们测试了AUT2[(4-({5-[(4R)-4-乙基-2,5-二氧代-1-咪唑烷基]-2-吡啶基}氧基)-2-(1-甲基乙基)苄腈]的作用,一种调节Kv3.1通道的化合物。通过将高阈值电流的激活转移到更多的负电位,AUT2降低了Fmr1-/y动物的神经元中的高阈值K电流,并增加了低阈值K电流。这降低了燃烧率,在体内,恢复了ABR的IV波。我们来自男女动物的结果表明,Kv3.1通道的调节可能具有治疗FXS患者感觉过敏的潜力。编码Kv3.1钾通道的mRNA是脆性X智力低下蛋白(FMRP)的第一个描述靶标之一。脆性X综合征是由FMRP丢失引起的,在人类和老鼠身上,导致对听觉刺激过敏。我们发现,在缺乏FMRP的小鼠中,与听觉脑干活动相对应的听觉脑反应(ABR)成分得到增强。这伴随着听觉脑干神经元的过度兴奋和钾电流的改变。用改变Kv3.1通道的电压依赖性的药物治疗使钾电流的不平衡正常化,以及体内ABR反应,这表明这些化合物可能有效治疗脆性X综合征的一些症状。
    Fragile X syndrome (FXS) is characterized by hypersensitivity to sensory stimuli, including environmental sounds. We compared the auditory brainstem response (ABR) recorded in vivo in mice lacking the gene (Fmr1 -/y ) for fragile X mental retardation protein (FMRP) with that in wild-type animals. We found that ABR wave I, which represents input from the auditory nerve, is reduced in Fmr1 -/y animals, but only at high sound levels. In contrast, wave IV, which represents the activity of auditory brainstem nuclei is enhanced at all sound levels, suggesting that loss of FMRP alters the central processing of auditory signals. Current-clamp recordings of neurons in the medial nucleus of the trapezoid body in the auditory brainstem revealed that, in contrast to neurons from wild-type animals, sustained depolarization triggers repetitive firing rather than a single action potential. In voltage-clamp recordings, K+ currents that activate at positive potentials (\"high-threshold\" K+ currents), which are required for high-frequency firing and are carried primarily by Kv3.1 channels, are elevated in Fmr1 -/y mice, while K+ currents that activate near the resting potential and inhibit repetitive firing are reduced. We therefore tested the effects of AUT2 [((4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-(1-methylethyl) benzonitrile], a compound that modulates Kv3.1 channels. AUT2 reduced the high-threshold K+ current and increased the low-threshold K+ currents in neurons from Fmr1 -/y animals by shifting the activation of the high-threshold current to more negative potentials. This reduced the firing rate and, in vivo, restored wave IV of the ABR. Our results from animals of both sexes suggest that the modulation of the Kv3.1 channel may have potential for the treatment of sensory hypersensitivity in patients with FXS.SIGNIFICANCE STATEMENT mRNA encoding the Kv3.1 potassium channel was one of the first described targets of the fragile X mental retardation protein (FMRP). Fragile X syndrome is caused by loss of FMRP and, in humans and mice, causes hypersensitivity to auditory stimuli. We found that components of the auditory brain response (ABR) corresponding to auditory brainstem activity are enhanced in mice lacking FMRP. This is accompanied by hyperexcitability and altered potassium currents in auditory brainstem neurons. Treatment with a drug that alters the voltage dependence of Kv3.1 channels normalizes the imbalance of potassium currents, as well as ABR responses in vivo, suggesting that such compounds may be effective in treating some symptoms of fragile X syndrome.
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  • 文章类型: Journal Article
    比索洛尔(BIS)是β1肾上腺素能受体的选择性拮抗剂。我们检查了BIS对垂体GH3,R1220细胞中M型K+电流(IK(M))或erg介导的K+电流(IK(erg))的影响,和海马mHippoE-14细胞。当GH细胞暴露于BIS时,IK(M)的振幅被抑制,IC50值为1.21μM。BIS诱导的IK(M)振幅抑制不受异丙肾上腺素或莱克多巴胺添加的影响,但被氟吡汀或伊伐布雷定减毒。在细胞附着电流中,BIS降低了M型K④(KM)通道的开放概率,随着通道平均开放时间的减少。BIS降低IK(erg)振幅,IC50值为6.42μM。进一步添加PD-118057减弱了BIS介导的IK抑制(erg)。在电流钳位条件下,BIS去极化增加了GH3细胞中自发动作电位的激发;添加氟吡汀,但不是莱克多巴胺,反向BIS诱导的点火速率。在R1220细胞中,BIS抑制IK(M);随后应用ML-213(Kv7.2通道激活剂)逆转了BIS诱导的电流抑制。在海马mHippoE-14神经元中,与BIS对IK(erg)的抑制作用相比,BIS对IK(M)的抑制作用更大。这表明在垂体细胞和海马神经元中,BIS的存在能够直接和差异地抑制IK(M)和IK(erg),尽管它拮抗β1-肾上腺素能受体。
    Bisoprolol (BIS) is a selective antagonist of β₁ adrenergic receptors. We examined the effects of BIS on M-type K⁺ currents (IK(M)) or erg-mediated K⁺ currents (IK(erg)) in pituitary GH3, R1220 cells, and hippocampal mHippoE-14 cells. As GH₃ cells were exposed to BIS, amplitude of IK(M) was suppressed with an IC50 value of 1.21 μM. The BIS-induced suppression of IK(M) amplitude was not affected by addition of isoproterenol or ractopamine, but attenuated by flupirtine or ivabradine. In cell-attached current, BIS decreased the open probability of M-type K⁺ (KM) channels, along with decreased mean opening time of the channel. BIS decreased IK(erg) amplitude with an IC50 value of 6.42 μM. Further addition of PD-118057 attenuated BIS-mediated inhibition of IK(erg). Under current-clamp conditions, BIS depolarization increased the firing of spontaneous action potentials in GH₃ cells; addition of flupirtine, but not ractopamine, reversed BIS-induced firing rate. In R1220 cells, BIS suppressed IK(M); subsequent application of ML-213(Kv7.2 channel activator) reversed BIS-induced suppression of the current. In hippocampal mHippoE-14 neurons, BIS inhibited IK(M) to a greater extent compared to its depressant effect on IK(erg). This demonstrated that in pituitary cells and hippocampal neurons the presence of BIS is capable of directly and differentially suppressing IK(M) and IK(erg), despite its antagonism of β₁-adrenergic receptors.
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