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Principal Investigator: MARK MERCOLA
Organization: STANFORD UNIVERSITY
Fiscal Year: 2024
Award: $569,291
Funding agency: National Heart Lung and Blood Institute
Ventricular arrhythmia and sudden cardiac death (SCD) is a prevalent complication of hypertrophic
cardiomyopathy (HCM) especially in young adults. Pathogenic variants of sarcomeric protein genes
cause about half of inherited HCM and about a third of sporadic HCM. Little is known, however, about
how sarcomeric protein variants lead to arrhythmia and sudden cardiac death. There is a major unmet
need for a better understanding of disease mechanisms in order to predict patients at risk for SCD and
design mechanism-based therapeutics.
To address this gap, we will apply high throughput functional genomics to identify individual protein
components of arrhythmogenic signaling, and establish their function using in vitro studies in iPSC-
derived cardiomyocytes (iPSC-CMs) and in vivo studies in HCM mutant mice. We will begin by
generating functional genomics probes of the intracellular arrhythmogenic signaling in iPSC-derived
cardiomyocytes carrying HCM causative variants in MYBPC3, MYH7 and TNNT2. The probes will be
identified based on screening synthetic miRNAs (syn-miRs) which collectively suppress nearly all
proteins in the cell and therefore make ideal probes of complex biology. Analysis of probe selectivity
for gene variants will indicate the existence of common and/or distinct signaling mechanisms. In parallel,
we will identify and characterize candidate pathways indicated from analysis of myectomy samples
from MYBPC3 mutant HCM patients. Once we have obtained pathway information and probes from
these two approaches, we will comprehensively determine the protein mediators by high throughput
functional evaluation in the MYBPC3 mutant iPSC-CMs. Based on the effect in the iPSC-CMs,
selectivity for MYBPC3 and potential as a drug target, we will prioritize the most promising candidate
targets for in vivo evaluation by AAV9 knockdown in HCM transgenic mice carrying a Mybpc3 mutation
homologous to that in the iPSC-CMs. We expect that modulating the function of the candidate
mediators will suppress arrhythmia and tachycardia in the Mybpc3 mutant mice.
In summary, these studies will increase our understanding of the arrhythmogenic signaling caused by
HCM mutations and promote the development of improved prognostic and mechanism-based
therapeutics for familial HCM patients. It will also increase our understanding of fundamental
cardiomyocyte biology that might underlie other cardiac diseases. The Specific Aims are: 1) Determine
if discrete signaling mechanisms cause arrhythmic susceptibility across “high” propensity HCM gene
variants, and 2) Comprehensively define the proteins that dictate electrical remodeling by functional
screening in MYBPC3 mutant iPSC-CMs and test their efficacy as therapeutic targets in an Mybpc3
mutant mouse model of HCM.
Terms: <Address><Affect><Arrhythmia><Asymmetric Septal Hypertrophy><Biological Function><Biological Process><Biology><Body Tissues><CaM KII><CaM PK II><CaM kinase II><CaMKII><Cardiac Arrhythmia><Cardiac Diseases><Cardiac Disorders><Cardiac Muscle Cells><Cardiac Myocytes><Cardiocyte><Cell Body><Cell Communication and Signaling><Cell Line><Cell Signaling><CellLine><Cells><Classification><Clinical><Complex><Complication><Consensus><Data><Development><Devices><Disease><Disease Progression><Disorder><Drug Targeting><Evaluation><Familial Asymmetric Septal Hypertrophy><Familial Hypertrophic Cardiomyopathy><Familial Ventricular Hypertrophy><Fingerprint><Gene Alteration><Gene Mutation><Gene Proteins><Gene variant><Genetic><Genetic Alteration><Genetic Change><Genetic defect><Genomic approach><Genotype><Goals><Heart Arrhythmias><Heart Diseases><Heart Muscle Cells><Heart myocyte><Hereditary ventricular hypertrophy><Hypertrophic Cardiomyopathy><Hypertrophic Obstructive Cardiomyopathy><Idiopathic Hypertrophic Subvalvular Stenosis><Idiopathic hypertrophic subaortic stenosis><Implantable Cardioverter-Defibrillators><Implantable Defibrillators><In Vitro><In vivo analysis><Individual><Intracellular Communication and Signaling><KO mice><Knock-out Mice><Knockout Mice><Knowledge><Lead><Life Style><Lifestyle><Link><Mediator><Mice><Mice Mammals><Micro RNA><MicroRNAs><Modeling><Molecular><Murine><Mus><Muscle Cell Contraction><Muscle Cells><Muscle Contraction><Muscle Relaxation><Muscle relaxation phase><Muscular Contraction><Mutant Strains Mice><Mutate><Mutation><Myocytes><Null Mouse><Occupational><Pathogenicity><Pathway interactions><Patients><Pb element><Phenotype><Predisposition><Process><Prognostic Marker><Protein Gene Products><Proteins><Publishing><QOL><Quality of life><Research><Risk><Sampling><Signal Pathway><Signal Transduction><Signal Transduction Systems><Signaling><Strains Cell Lines><Susceptibility><Systematics><Tachycardia><Testing><Therapeutic><Therapeutic Intervention><Thick Filament><Thin Filament><Tissues><Transgenic Mice><Validation><Variant><Variation><Ventricular Arrhythmia><Ventricular Tachycardia><adult youth><allele variant><allelic variant><biological signal transduction><calcium-dependent CaM kinase II><calmodulin-dependent protein kinase II><cardiomyocyte><causal allele><causal gene><causal mutation><causal variant><causative mutation><causative variant><congenital hypertrophic cardiomyopathy><cultured cell line><death risk><design><designing><developmental><functional genomics><genetic variant><genome mutation><genomic effort><genomic strategy><genomic variant><heart disorder><heavy metal Pb><heavy metal lead><hypertrophic myocardiopathy><iPS><iPS cell derived cardiomyocytes><iPSC><iPSC derived cardiomyocytes><iPSCs><implantation><improved><in vivo><in vivo evaluation><in vivo testing><induced pluripotent cell><induced pluripotent stem cell><induced pluripotent stem cell derived cardiomyocytes><inducible pluripotent stem cell><inherited hypertrophic cardiomyopathy><insight><intervention therapy><knock-down><knockdown><miRNA><miRNAs><mortality risk><mouse model><mouse mutant><murine model><mutant><mutant mouse model><network models><new therapeutic approach><new therapeutic intervention><new therapeutic strategies><new therapy approaches><new treatment approach><new treatment strategy><novel><novel therapeutic approach><novel therapeutic intervention><novel therapeutic strategies><novel therapy approach><pathway><prevent><preventing><prognostic><prognostic biomarker><prognostic tool><protein protein interaction><screening><screenings><sudden cardiac death><therapeutic target><tool><validations><young adult><young adulthood>