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Principal Investigator: Jason Becker
Organization: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
Fiscal Year: 2024
Award: $744,195
Funding agency: National Heart Lung and Blood Institute
Project Summary:
Multiple acquired and genetic conditions can lead to pathological left ventricular hypertrophy (LVH). It has been
recognized for over 50 years that pathological LVH is associated with increased mortality in the human
population, and it is strongly associated with both heart failure with preserved systolic function (HFpEF) and
heart failure with reduced systolic function (HFrEF). At the tissue level, the primary cause of LVH is
cardiomyocyte hypertrophy, and there are a multitude of intracellular signaling pathways involved in
hypertrophic cardiomyocyte growth. However, non-cardiomyocyte cell populations also contribute to
pathological ventricular remodeling in LVH and the downstream sequelae of this disease. Therefore, it is
critical to understand not only the primary causes of pathological cardiomyocyte growth but also how the
myocardial microenvironment responds to these changes. To uncover mechanisms regulating pathological LV
remodeling, we utilize multiple murine models that harbor sarcomere gene mutations which are common
genetic causes of LVH in humans. Previously, we discovered that loss of the sarcomere protein MYBPC3
causes rapid changes in early post-natal cardiomyocyte growth through dysregulated cell cycle pathways
causing cardiomyocyte endoreplication (DNA replication without cell division). Next, we found that
dysregulated cardiomyocyte cell cycle activity leads to replication stress induced DNA damage and activation
of DNA damage response (DDR) pathways in cardiomyocytes. We have now discovered that the DDR effector
protein, murine double mutant 2 (MDM2), plays an important role in regulating pathological LV remodeling in
both genetic and pressure overload LVH models. We hypothesize that the MDM2-HIF signaling axis is a key
regulator of pathological ventricular remodeling in genetic and acquired forms of myocardial hypertrophy. To
test this hypothesis, we will pursue the following aims: Aim 1: Define how MDM2-HIF signaling regulates
microvasculature dysfunction and LV remodeling in genetic models of LVH. Aim 2: Determine how MDM2-HIF
signaling regulates myocardial metabolism in genetic models of LVH. Aim 3: Define how cardiomyocyte
MDM2-HIF signaling regulates pathological LV remodeling secondary to pressure overload in the adult heart.
At the conclusion of these innovative and high impact studies, we will have defined a novel role for MDM2-HIF
signaling during key stages of pathological left ventricular remodeling in both genetic and acquired causes.
Through selective modulation of key components of this pathway our goal is to disrupt maladaptive myocardial
remodeling responses and uncover novel therapeutic opportunities for both genetic and non-genetic forms of
human cardiomyopathy.
Terms: <21+ years old><Adult><Adult Human><Asymmetric Septal Hypertrophy><Blood capillaries><Body Tissues><Cardiac Muscle Cells><Cardiac Myocytes><Cardiocyte><Cardiomyopathies><Cause of Death><Cell Body><Cell Communication and Signaling><Cell Cycle><Cell Division Cycle><Cell Signaling><Cell division><Cells><Chemicals><DNA Damage><DNA Injury><DNA Replication><DNA Synthesis><DNA biosynthesis><Diastolic heart failure><Disease><Disorder><Dysfunction><Functional disorder><Gene Alteration><Gene Mutation><Generalized Growth><Genetic><Genetic Diseases><Genetic Models><Glycolysis><Goals><Growth><HIF 1 alpha><HIF-1alpha><HIF1-Alpha><HIF1A><HIF1A gene><HIF1α><Heart><Heart Muscle Cells><Heart failure><Heart myocyte><Hereditary ventricular hypertrophy><Human><Hypertrophic Cardiomyopathy><Hypertrophic Obstructive Cardiomyopathy><Hypertrophy><Idiopathic Hypertrophic Subvalvular Stenosis><Idiopathic hypertrophic subaortic stenosis><Intermediary Metabolism><Intracellular Communication and Signaling><LV remodeling><Left Ventricular Hypertrophy><Left Ventricular Remodeling><MOP1><Metabolic><Metabolic Processes><Metabolism><Mice><Mice Mammals><Modeling><Modern Man><Molecular><Murine><Mus><Myocardial><Myocardial Diseases><Myocardial Disorder><Myocardial depression><Myocardial dysfunction><Myocardiopathies><Pathologic><Pathologic Processes><Pathological Processes><Pathway interactions><Patients><Physiopathology><Play><Population><Proteins><Role><Sarcomeres><Secondary to><Signal Pathway><Signal Transduction><Signal Transduction Systems><Signaling><Testing><Tissue Growth><Tissues><Ventricle Remodeling><Ventricular Cardiac Remodeling><Ventricular Myocardial Remodeling><Ventricular Remodeling><adulthood><biological signal transduction><capillary><cardiac dysfunction><cardiac failure><cardiomyocyte><density><disease model><disorder model><experiment><experimental research><experimental study><experiments><gain of function><genetic condition><genetic disorder><heart dysfunction><heart failure with preserved systolic function><hypertrophic myocardiopathy><improved><innovate><innovation><innovative><left ventricle remodeling><loss of function><mortality><mouse model><murine model><mutant><myocardial remodeling><myocardium disease><myocardium disorder><new drug treatments><new drugs><new pharmacological therapeutic><new therapeutics><new therapy><next generation therapeutics><non-genetic><nongenetic><novel><novel drug treatments><novel drugs><novel pharmaco-therapeutic><novel pharmacological therapeutic><novel therapeutics><novel therapy><ontogeny><pathophysiology><pathway><postnatal><pressure><prevent><preventing><replication stress><response><social role>