Cellular and clinical phenotypes of novel SCN5a mutations

新 SCN5a 突变的细胞和临床表型

• 批准号: 8081018
• 负责人: JONATHAN C MAKIELSKI
• 金额: $ 40.54万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-15 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8081018
• 关键词: Accounting; Action Potentials; Address; Adrenergic Agents; Affect; Alleles; Applications Grants; Arrhythmia; Biochemical; Calcium; Cardiac; Caveolins; Cell model; Cells; Cessation of life; Clinical; Complex; Data; Diagnosis; Disadvantaged; Disease; Dominant-Negative Mutation; Environment; Event; Functional disorder; Genes; Genetic Polymorphism; Genetic Variation; Genotype; Goals; Health; Heart Diseases; Heart failure; Human; Inherited; Injury; Ion Channel Protein; Ions; Ischemia; Kinetics; Link; Long QT Syndrome; Macromolecular Complexes; Mediating; Membrane; Modeling; Molecular; Muscle Cells; Mutation; Myocardial; Organ; Other Genetics; Oxidoreductase; Patients; Pharmaceutical Preparations; Phenotype; Phosphorylation; Process; Proteins; RNA Splicing; Signal Transduction; Sudden infant death syndrome; Syndrome; System; Tissues; Transgenic Mice; Variant; adrenergic; clinical phenotype; clinically relevant; cohort; developmental genetics; follow-up; human disease; improved; inorganic phosphate; insight; molecular phenotype; novel; prevent; syntrophin; syntrophin alpha1; trafficking; voltage clamp

DESCRIPTION (provided by applicant): Dysfunction of the Na current (INa) flowing through the a subunit of the cardiac Na channel encoded by SCN5A participates in pathogenic mechanisms for arrhythmia, heart failure, and ischemia. The mechanism for the clinical phenotype of a particular genotype comes from the underlying molecular phenotype (e.g., INa amplitude and kinetics) and cellular phenotype (e.g., action potentials) caused by the mutation. In the previous period we focused on the molecular phenotype in heterologous expression systems associated with mutations of SCN5A. We discovered a ubiquitous human splice variant (Q1077del) that affects function of other mutations, clinically relevant functional effects of 8 common polymorphisms (e.g. H558R), and drug rescue of trafficking defective mutations. We also showed a novel dominant negative effect of one Brugada syndrome SCN5A allele on another. Two aims (1 and 3) of this proposal follow up on these pathogenic mechanisms of genetic variation in SCN5A. Two additional aims (2 and 4) take the project in a new direction. It is increasingly clear that INa is a function of the SCN5A macromolecular complex where more than one a subunit combines with ¿ subunits and other channel interacting proteins (ChIPs) such as caveolin and syntrophins. Pathogenic genotypes have yet to be discovered in many patients from cohorts with suspected inherited arrhythmia syndromes (LQTS, SIDS, SUDS). From patients in these cohorts we have recently discovered mutations in putative ChIPs (CAV3, SNTA1, GPD1L, SCN4B) and shown that they affect INa in a way that may be pathogenic. In the next period we will continue a recently implemented more integrative approach to the study by expressing mutations in myocardial cells. This more complete cardiac environment allows for characterization of both the cellular phenotype and the molecular phenotype under relevant conditions such as adrenergic state in the presence of the intact macromolecular complex. In Aim 1 we will discover pathogenic mechanisms involving an SCN5A variant by characterizing the molecular and cellular phenotypes. In Aim 2 we will discover mutations in novel genes encoding putative SCN5A ChIPs from patients with suspected inherited arrhythmia and no known pathogenic genotype, and define molecular and cellular phenotypes to establish an INa mediated mechanism. In Aim 3 we will investigate SCN5A a-a subunit interactions (such as dominant negative and rescue effects). In Aim 4 we will address molecular mechanisms accounting for the molecular phenotype of altered INa for two novel arrhythmia genes (SNTA1 and GPD1L). The integrated approach of this proposal takes into account the SCN5A macromolecular complex in more native systems to determine both molecular and cellular phenotypes, and molecular mechanisms underlying the molecular phenotype. In addition to better understanding of the SCN5A macromolecular complex, the expected results should yield insight into pathogenetic mechanisms of the genotype-phenotype link for inherited and acquired arrhythmia and other cardiac disease. PUBLIC HEALTH RELEVANCE: Inherited mutations in the gene that encodes a membrane ion channel protein called SCN5A cause injury and death from arrhythmia in syndromes such as Sudden Infant Death Syndrome (SIDS), Sudden Unexpected Death Syndrome (SUDS), and long QT syndrome (LQTS). This project will discover mutations in novel genes (not SCN5A but related) discovered in patients with these syndromes and how they interact with SCN5A to alter function and cause arrhythmia. The results are expected to improve diagnosis of these inherited syndromes and suggest ways to treat and prevent them.

描述（由申请人提供）：流经由SCN 5A编码的心脏Na通道α亚基的Na电流（INa）功能障碍参与心律失常、心力衰竭和缺血的致病机制。特定基因型的临床表型的机制来自潜在的分子表型（例如，INa幅度和动力学）和细胞表型（例如，动作电位）引起的突变。在前一阶段，我们集中在与SCN 5A突变相关的异源表达系统中的分子表型。我们发现了一种普遍存在的人类剪接变异体（Q1077 del），它影响其他突变的功能，8种常见多态性（例如H558 R）的临床相关功能效应，以及运输缺陷突变的药物拯救。我们还发现了一个Brugada综合征SCN 5A等位基因对另一个等位基因的新的显性负效应。本提案的两个目的（1和3）是跟进SCN 5A遗传变异的这些致病机制。另外两个目标（2和4）将该项目引向新的方向。越来越清楚的是，INa是SCN 5A大分子复合物的功能，在SCN 5A大分子复合物中，多于一个a亚基与a亚基和其他通道相互作用蛋白（ChIP）如小窝蛋白和突触营养蛋白结合。致病基因型尚未在许多疑似遗传性心律失常综合征（LQTS，SIDS，SUDS）患者中发现。从这些队列中的患者中，我们最近发现了推定的ChIP（CAV 3，SNTA 1，GPD 1 L，SCN 4 B）突变，并表明它们以可能致病的方式影响INa。在下一个阶段，我们将继续最近实施的更综合的方法来表达心肌细胞中的突变的研究。这种更完整的心脏环境允许在相关条件下表征细胞表型和分子表型，例如在完整大分子复合物存在下的肾上腺素能状态。在目标1中，我们将通过表征分子和细胞表型来发现涉及SCN 5A变体的致病机制。在目标2中，我们将发现来自疑似遗传性心律失常且无已知致病基因型的患者的编码推定SCN 5A ChIP的新基因中的突变，并定义分子和细胞表型以建立INa介导的机制。在目标3中，我们将研究SCN 5A a-a亚基相互作用（如显性负效应和拯救效应）。在目标4中，我们将解决两个新的心律失常基因（SNTA 1和GPD 1 L）的分子表型改变INa的分子机制。该建议的综合方法考虑了更天然系统中的SCN 5A大分子复合物，以确定分子和细胞表型以及分子表型背后的分子机制。除了更好地了解SCN 5A大分子复合物，预期的结果应该产生深入了解遗传性和获得性心律失常和其他心脏病的基因型-表型联系的发病机制。公共卫生相关性：编码称为SCN 5A的膜离子通道蛋白的基因中的遗传突变导致心律失常综合征的损伤和死亡，如婴儿猝死综合征（SIDS），意外猝死综合征（SUDS）和长QT综合征（LQTS）。该项目将发现在这些综合征患者中发现的新基因（不是SCN 5A，而是相关基因）的突变，以及它们如何与SCN 5A相互作用以改变功能并导致心律失常。这些结果有望改善这些遗传综合征的诊断，并提出治疗和预防的方法。

项目成果

Differential modulation of late sodium current by protein kinase A in R1623Q mutant of LQT3.

LQT3 R1623Q 突变体中蛋白激酶 A 对晚钠电流的差异调节。

• DOI: 10.1016/j.lfs.2009.01.001
• 发表时间: 2009
• 期刊: Life sciences
• 影响因子: 6.1
• 作者: Tsurugi,Takuo;Nagatomo,Toshihisa;Abe,Haruhiko;Oginosawa,Yasushi;Takemasa,Hiroko;Kohno,Ritsuko;Makita,Naomasa;Makielski,JonathanC;Otsuji,Yutaka
• 通讯作者: Otsuji,Yutaka

A novel mechanism for the treatment of angina, arrhythmias, and diastolic dysfunction: inhibition of late I(Na) using ranolazine.

• DOI: 10.1097/fjc.0b013e3181a1b9e7
• 发表时间: 2009-10
• 期刊: Journal of cardiovascular pharmacology
• 影响因子: 3
• 作者: Maier LS

Sudden unexplained nocturnal death syndrome in Southern China: an epidemiological survey and SCN5A gene screening.

• DOI: 10.1097/paf.0b013e3181d03d02
• 发表时间: 2011-12
• 期刊: The American journal of forensic medicine and pathology
• 作者: Cheng J;Makielski JC;Yuan P;Shi N;Zhou F;Ye B;Tan BH;Kroboth S
• 通讯作者: Kroboth S

Arrhythmogenic Biophysical Phenotype for SCN5A Mutation S1787N Depends upon Splice Variant Background and Intracellular Acidosis.

• DOI: 10.1371/journal.pone.0124921
• 发表时间: 2015
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Hu RM;Tan BH;Tester DJ;Song C;He Y;Dovat S;Peterson BZ;Ackerman MJ;Makielski JC
• 通讯作者: Makielski JC

Na(+) current in human ventricle: implications for sodium loading and homeostasis.

• DOI: 10.1111/j.1540-8167.2006.00380.x
• 发表时间: 2006-05-01
• 期刊: Journal of cardiovascular electrophysiology
• 影响因子: 2.7
• 作者: Makielski, Jonathan C;Farley, Amanda L
• 通讯作者: Farley, Amanda L