Atrial Fibrillation Post-GWAS: Mechanisms to Treatment

OVERALL COMPONENT PROJECT/SUMMARY ABSTRACT Atrial fibrillation (AF), the most common cardiac arrhythmia, afflicts the U.S. and world with increasing prevalence. AF incidence, progression to persistent AF, and AF complications, including stroke, are fed by increasing obesity and age. Current therapies are limited by risks and limited efficacy, worse as AF progresses, but no new pharmacologic agents have been approved for AF in >10 years. With identification of >100 genetic loci that predispose to AF risk in genome-wide association studies (GWAS), the hope has been that genetics would yield novel therapeutic targets. However, even for the top locus on chr. 4q25 near PITX2, a gene involved in formation of pulmonary veins, the target of AF ablation, mechanisms linking variants to AF remain elusive. Genetic findings have so far failed to yield clinically actionable results. To fill these gaps, we seek to go beyond GWAS findings to identify direct genomic mechanisms underlying AF and better understand their interactions with environment, comorbidities or cell stressors. Our long-term goal is to use genomic findings to personalize preventive and therapeutic strategies for AF. Our overall P01 theme is to translate AF genetic discoveries towards the bedside, focusing on genes to mechanisms, genes to drugs, and interactions of genes with metabolism and environment. We build on strong preliminary data and coalesce unique human atrial tissue biorepository and genomic data resources, novel cell and animal models, and complementary expertise from our multidisciplinary team with a strong collaboration history. Our Central Hypothesis is that genomic mechanistic discoveries in AF cellular and animal models will translate to human therapies. Our thematic aims include: 1) Identify causal genes and functional mechanisms with a goal towards identification of new therapeutic approaches for AF; 2) Investigate metabolic and inflammatory mechanisms, implicated by genomics studies to be important in AF pathophysiology, to identify new therapeutic targets for AF prevention and treatment; and 3) Identify candidate novel drugs for AF and develop a pipeline for in vitro and in vivo functional testing of candidate therapies. Project 1 Genes to Function will determine causal genes, variants and mechanisms underlying two AF GWAS loci. Project 2 Genes and Metabolism will study the contribution of mitochondrial dysfunction to AF onset and progression. Early Stage Investigator Project Genes and Nutrition builds on novel associations of AF with trimethylamine N-oxide (TMAO), produced by gut microbiota from precursors such as choline found in eggs, meats and cheeses. Project 4 Genes to Omics-Informed Drugs will identify mechanisms and repurposable drugs to prevent AF progression. Projects are supported by 4 Cores providing administration, engineered heart tissue and atrial phenotyping, electrophysiology, and network and systems biology analytics support that synergize discovery and translation in AF and increase the scope and impact of each project. All P01 components aim to bridge basic research in AF towards clinical utility, thereby advancing genomic data and research towards the bedside to help our patients suffering from atrial fibrillation.