Project 1 - Genes to Function: Causal Genes and their Roles in Cardiomyocyte and Atrial Physiology

项目 1 - 发挥功能的基因：因果基因及其在心肌细胞和心房生理学中的作用

• 批准号: 10410648
• 负责人: Jonathan D Smith
• 金额: $ 50.72万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10410648
• 关键词: 10q22; Actins; Action Potentials; Address; Adult; Affect; Age; Atrial Fibrillation; Binding; Breeding; Calcium; Cardiac Myocytes; Cell Nucleus; Cessation of life; Chromosomes; Clinical; Collaborations; Complex; Cytoplasm; Cytoskeleton; Data; Development; Doctor of Philosophy; Dominant-Negative Mutation; Electrophysiology (science); Engineering; FDA approved; Gene Expression; Gene Expression Regulation; Genes; Goals; Heart Atrium; Heart failure; Heritability; Human; Human Genome; Incidence; Individual; Ion Transport; Knockout Mice; Knowledge; Left; Left atrial structure; Linkage Disequilibrium; Metabolism; Molecular; Morphology; Nuclear; Nuclear Envelope; Obesity; Pathway interactions; Pharmaceutical Preparations; Physiology; Predisposition; Program Description; Protein Isoforms; Proteins; Quantitative Trait Loci; Research; Risk; Role; Sarcoplasmic Reticulum; Single Nucleotide Polymorphism; Sinus; Stroke; Structure; Tamoxifen; Testing; Therapeutic; Tissues; Transcript; Transcription Initiation Site; Transgenic Mice; Variant; Ventricular; Work; analysis pipeline; auricular appendage; biracial; causal variant; cohort; design; drug candidate; functional genomics; gain of function; genetic association; genetic variant; genome wide association study; genomic locus; heart function; human stem cells; improved; in vivo; insight; knock-down; mouse model; novel; novel therapeutic intervention; overexpression; programs; response; risk variant; stem cell differentiation; therapeutic evaluation; transcriptome; transcriptome sequencing; transcriptomics

Project 1 Summary: Atrial fibrillation (AF) increases risk of heart failure, stroke and death, and its incidence increases with age and obesity. Human genome wide association studies (GWAS) have identified ~140 genetic loci associated with AF susceptibility, but it still takes dedicated functional and molecular studies to identify the causal gene, the causal genetic variant, and the mechanisms for AF association. We are very excited to pursue two AF risk loci on chromosomes 10q22 (SYNPO2L and MYOZ1 genes) and 14q23 (SYNE2 gene). We are poised to discover the mechanism by which these two loci increase AF susceptibility, and identify gene centric repurposable drugs, which may be targeted to individuals carrying these risk alleles. We chose both loci for study as the GWAS single nucleotide polymorphism (SNP) was associated with expression of a nearby gene; thus, the causal SNP, which can be in linkage disequilibrium with the GWAS SNP, may work by regulating gene expression. These associations with gene expression were for specific transcript isoforms of SYNPO2L and SYNE2 due to alternative transcription start sites. In Aim 1, we will study the complex AF locus on chromosome 10q22, where the AF risk allele is associated with decreased expression of MYOZ1, but increased expression of the shorter isoforms of SYNPO2L. Both of these genes encode Z disk proteins, which may directly affect contractility and secondarily alter Ca2+ handling that may impact cellular electrophysiology. We will study how changes in the expression of MYOZ1 and the SYPO2L isoforms alter contractility and electrophysiology in human stem cells differentiated into atrial-like cardiomyocytes (a-iCMs) and engineered heat tissue (EHT). In Aim 2, we will build on our preliminary human iCM studies, where we found that the chromosome 14q23 AF risk allele is associated with less expression of a SYNE2 short isoform. SYNE2 encodes a protein that connects the nucleus to the cytoplasm, but the short isoform does not bind to the cytoskeleton, and acts as a dominant negative to disrupt the nuclear-cytoplasm connection. RNAseq from SYNE2 short isoform overexpression in a-iCMs showed a large effect on Ca2+ handling proteins. We looked at Ca2+ handling and action potentials; knockdown of all SYNE2 isoforms led to increased early afterdepolarizations, which was rescued by over expression of the short isoform. Short isoform over expression also decreased peak Ca2+ content. We discovered that the SYNE2 short isoform also binds to the sarcoplasmic reticulum. In this aim we are poised to determine if over expression of the SYNE2 short isoform can protect against AF in a mouse model of spontaneous AF. In collaboration with SC3 and P3, Aim 3 will use the RNAseq data from Aims 1 and 2 to identify “gene effect modules”, for which we will identify module altering repurposalbe drugs, which will be tested for beneficial effects in a-iCMs and EHTs. Successful completion of our aims will make significant contributions to AF functional genomics and therapeutics.

项目1摘要： 心房颤动（AF）增加心力衰竭、中风和死亡的风险，其发病率随着年龄的增长而增加， 肥胖人类全基因组关联研究（GWAS）已经确定了约140个遗传基因座， 房颤的易感性，但它仍然需要专门的功能和分子研究，以确定致病基因， 致病性遗传变异和AF相关机制。我们很高兴能够追踪两个房颤风险位点， 位于染色体10 q22（SYNPO 2L和MYOZ 1基因）和14 q23（SYNE 2基因）上。我们准备去发现 这两个基因座增加房颤易感性的机制，并确定基因中心可重复利用 这些药物可能针对携带这些风险等位基因的个体。我们选择这两个位点进行研究， GWAS单核苷酸多态性（SNP）与附近基因的表达相关;因此， 与GWAS SNP连锁不平衡的致病SNP可能通过调节基因表达而起作用， 表情这些与基因表达的相关性是针对SYNPO 2L的特异性转录异构体， SYNE 2由于替代转录起始位点。在目标1中，我们将研究复杂的AF轨迹， 染色体10 q22，其中AF风险等位基因与MYOZ 1表达降低相关，但 SYNPO 2L的较短同种型的表达增加。这两个基因都编码Z盘蛋白， 可能直接影响收缩性，并其次改变可能影响细胞电生理学的Ca 2+处理。 我们将研究MYOZ 1和SYPO 2L亚型表达的变化如何改变收缩性， 在分化成心房样心肌细胞（a-iCM）和工程化的人干细胞中的电生理学 加热组织（EHT）。在目标2中，我们将建立在我们初步的人类iCM研究的基础上，我们发现， 染色体14 q23 AF风险等位基因与SYNE 2短同种型的较少表达相关。SYNE2 编码一种连接细胞核和细胞质的蛋白质，但短的同种型不结合细胞质。 细胞骨架，并作为一个显性负破坏核质连接。RNAseq来自 α-iCM中的SYNE 2短同种型过表达显示出对Ca 2+处理蛋白的大的影响。我们看了 Ca 2+处理和动作电位;所有SYNE 2亚型的敲低导致早期 后去极化，这是拯救了短亚型的过度表达。短亚型过表达 降低Ca 2+峰值含量。我们发现，SYNE 2短同种型也结合到 肌浆网在这个目标中，我们准备确定是否过表达SYNE 2短亚型 在自发性房颤小鼠模型中，Aim 3可以预防房颤。与SC 3和P3合作，Aim 3将使用 来自目标1和2的RNAseq数据，以鉴定“基因效应模块”，我们将鉴定模块改变 这些药物将在a-iCM和EHT中测试有益效果。成功完成 我们的目标将为AF功能基因组学和治疗学做出重大贡献。