Unmasking Conduction Deficits in the Scn5a+/- Mouse Model of Brugada Syndrome

揭示 Scn5a/Brugada 综合征小鼠模型中的传导缺陷

• 批准号: 10315616
• 负责人: Grace Anna Bonson
• 金额: $ 4.29万
• 依托单位: VIRGINIA POLYTECHNIC INST AND ST UNIV
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-10 至 2023-08-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10315616
• 关键词: Action Potentials; Adhesions; Animals; Arrhythmia; Attenuated; Biomedical Research; Brugada syndrome; Calcium; Cardiac Electrophysiologic Techniques; Case Study; Cell membrane; Cells; Child; Clinical; Conflict (Psychology); Connexin 43; Connexins; Coupling; Development; Diagnosis; Diagnostic; Disease; Edema; Electrocardiogram; Electrolytes; Electrophysiology (science); Equilibrium; Event; Experimental Designs; Fluorescence; Genes; Genetic; Goals; Heart; Heart Abnormalities; Hyponatremia; Image; Intercalated disc; Investigation; Lead; Learning; Mannitol; Maps; Measures; Mediating; Membrane Potentials; Mentors; Mentorship; Microelectrodes; Modeling; Monitor; Mus; Mutation; Nature; Optics; Pathologic; Pathology; Patients; Pattern; Peptides; Perfusion; Pharmaceutical Preparations; Physiological; Plasma; Population; Predictive Value; Reporting; Research; Research Institute; Research Personnel; Resolution; Rest; Risk; Route; Side; Sodium; Sodium Channel; Structure; Symptoms; Syndrome; Techniques; Testing; Training; Transmission Electron Microscopy; Universities; Variant; Ventricular; Ventricular Arrhythmia; Virginia; Washington; Width; Wild Type Mouse; Work; career; clinically relevant; driving force; experience; experimental study; extracellular; high risk; in vivo; interstitial; loss of function mutation; mouse model; novel; novel diagnostics; prevent; response; skills; spatiotemporal; structural heart disease; sudden cardiac death; theories; therapy development; tool; voltage; voltage sensitive dye; young adult

Project Summary Brugada Syndrome (BrS) is a rare but severe disease that can lead to arrhythmias and sudden cardiac death in children and young adults with no structural heart disease. The most prominent genetic contributor to this disease is loss of function mutations in scn5a, the gene encoding the voltage gated sodium channel, Nav1.5. However, many BrS patients with these mutations are asymptomatic until experiencing a major arrhythmic event, making this syndrome “concealed” in nature. While diagnostic drug challenges exist for those at high risk of becoming symptomatic, they have low positive predictive value. The relationship between loss of Nav1.5, conduction slowing, and arrhythmias is well established, and it is possible that concealed conduction slowing is the underlying driver of BrS pathology. This proposal aims to utilize a scn5a heterozygous mouse model of BrS to determine whether modulation of ephaptic coupling within the intact heart can unmask BrS-associated conduction slowing. In Aim 1, ephaptic coupling will be manipulated by altering the width of the perinexus, a nanodomain of the intercalated disk, in the isolated, Langendorff-perfused Scn5a+/- and WT mouse heart. Conduction velocity will be assessed using optical mapping, wherein the intact heart is perfused with a voltage sensitive dye and imaged with high spatio-temporal resolution. Dr. Rob Gourdie at Virginia Tech will provide technical mentorship while the fellow learns the technique of transmission electron microscopy. She will then employ this technique to confirm changes in perinexal width. The long-term goal for this component is to develop a novel diagnostic for BrS. Aim 2 of this proposal will investigate whether hyponatremia can unmask greater conduction slowing in the Sn5a+/- mouse heart relative to its WT counterpart. Again, the fellow will utilize optical mapping to assess conduction in response to this change. She has recently collaborated with the lab of Dr. Matt Kay at George Washington University to learn how to build and implement floating microelectrodes, and will continue to work with this group in order establish this technique in Dr. Poelzing's lab at the Fralin Biomedical Research Institute at Virginia Tech Carilion (FBRI). The floating microelectrode technique will provide stable and direct electrophysiological measures from intact, beating mouse hearts in response to hyponatremia. The long- term goal for this component is to assess whether monitoring plasma sodium and calcium levels in BrS patients may be an effective approach to prevent clinical manifestations of BrS. Together, the results of this proposal may suggest new avenues of investigation for novel diagnostics and treatments for BrS. All of the proposed experiments will be conducted at FBRI, the collaborative biomedical research campus of Virginia Tech. With the support of her sponsor and mentoring team, this project will also be the basis to expand and strengthen the fellow's technical and professional skill sets in order to prepare her for the next step in her career plan as a postdoctoral associate en route to becoming an independent researcher in the field of cardiac electrophysiology.

项目摘要 Brugada综合征（BRS）是一种罕见但严重的疾病，可能导致心律不齐和心脏猝死 没有结构性心脏病的儿童和年轻人。对这种疾病的最突出的遗传因素 IS是SCN5A中功能突变的丧失，编码电压门控钠通道的基因NAV1.5。然而， 许多患有这些突变的BRS患者是无症状的，直到发生重大心律不齐事件，使 这种综合症本质上“隐藏”。虽然有诊断药物挑战的人有高风险 有症状的，它们的正预测价值低。 NAV1.5的损失，传导之间的关系 放缓，心律不齐得到很好的建立，隐藏传导放缓可能是 BRS病理学的基础驱动因素。该建议旨在利用BRS的SCN5A杂合小鼠模型 确定在完整心脏内部的字段耦合的调制是否可以揭示与BR相关的 传导放慢。在AIM 1中，将通过更改Perinexus的宽度来操纵字母耦合 插入式磁盘的纳米域，在孤立的，langendorff perded的SCN5A +/-和WT小鼠心脏中。 将使用光学映射评估传导速度，其中完整的心脏被灌注电压 敏感的染料并以高时空分辨率成像。弗吉尼亚理工大学的Rob Gourdie博士将提供 当研究员学习传输电子显微镜技术时，技术心态。然后她会 员工这项技术确认周围宽度的变化。该组成部分的长期目标是发展 BRS的新型诊断。该提案的目标2将调查低钠血症是否可以更大 相对于其WT对应物，SN5A +/-小鼠心脏的传导减慢。同样，同伴将利用光学 映射到评估传导以应对这一变化。她最近与马特博士的实验室合作 乔治华盛顿大学的凯（Kay）学习如何建造和实施浮动微电极，并将 继续与该小组合作，以便在弗拉林生物医学博士的实验室中建立此技术 弗吉尼亚理工大学（FBRI）的研究所。浮动微电极技术将提供稳定和 完整的直接电生理测度对低钠血症响应小鼠心脏。长期 该组件的术语目标是评估BRS患者的血浆钠和钙水平是否监测 可能是防止BR临床表现的有效方法。一起，该提案的结果 可能会暗示新的BRS诊断和治疗方法调查的新途径。所有提议的 实验将在弗吉尼亚理工学院的合作生物医学研究园区FBRI进行。与 支持她的赞助商和心理团队，该项目也将成为扩展和加强的基础 同伴的技术和专业技能，以便为她准备职业生涯计划的下一步做好准备 在成为心脏电生理领域的独立研究人员的途径。