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: 10646358
• 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/10646358
• 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; Dedications; 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概要： 心房颤动（AF）会增加心力衰竭、中风和死亡的风险，其发病率随着年龄的增长而增加 人类全基因组关联研究 (GWAS) 已确定约 140 个与肥胖相关的基因位点。 AF 易感性，但仍需要专门的功能和分子研究来识别致病基因，即 因果遗传变异以及 AF 关联机制 我们非常高兴能够探索两个 AF 风险位点。 我们准备在染色体 10q22（SYNPO2L 和 MYOZ1 基因）和 14q23（SYNE2 基因）上发现。 这两个基因座增加 AF 易感性的机制，并确定以基因为中心的可重新利用 我们选择两个基因座作为研究对象 GWAS 单核苷酸多态性 (SNP) 与附近基因的表达相关； 因果SNP可能与GWAS SNP连锁不平衡，可能通过调节基因发挥作用 这些与基因表达的关联针对 SYNPO2L 和 SYNPO2L 的特定转录亚型。 SYNE2 由于替代转录起始位点而产生。 在目标 1 中，我们将研究复杂的 AF 基因座。 染色体 10q22，其中 AF 风险等位基因与 MYOZ1 表达降低相关，但 SYNPO2L 较短亚型的表达增加，这两个基因都编码 Z 盘蛋白。 可能直接影响收缩性，其次改变可能影响细胞电生理学的 Ca2+ 处理。 我们将研究 MYOZ1 和 SYPO2L 亚型的表达变化如何改变收缩性和 人类干细胞分化为心房样心肌细胞（a-iCM）并经过改造的电生理学 在目标 2 中，我们将建立在我们的初步人体 iCM 研究的基础上，我们发现 染色体 14q23 AF 风险等位基因与 SYNE2 短亚型的表达较少有关。 编码一种连接细胞核和细胞质的蛋白质，但短亚型不与 细胞骨架，并作为显性失活破坏核-细胞质连接。 我们研究了 a-iCM 中 SYNE2 短亚型的过度表达对 Ca2+ 处理蛋白的巨大影响。 Ca2+ 处理和动作电位；所有 SYNE2 同种型的敲低导致早期增加 后去极化，这是通过短亚型的过度表达来挽救的。 还降低了峰值 Ca2+ 含量。我们发现 SYNE2 短异构体也与 SYNE2 结合。 为此，我们准备确定 SYNE2 短亚型是否过度表达。 Aim 3 将与 SC3 和 P3 合作，在自发性 AF 小鼠模型中预防 AF。 来自目标 1 和 2 的 RNAseq 数据来识别“基因效应模块”，为此我们将识别模块改变 重新用途药物，将在 a-iCM 和 EHT 中测试其有益效果。 我们的目标将为房颤功能基因组学和治疗学做出重大贡献。