Post-translational modification of the thin filament leads to progressive pump dysfunction

细丝的翻译后修饰导致进行性泵功能障碍

• 批准号: 10386787
• 负责人: Margaret V Westfall
• 金额: $ 39万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-05 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10386787
• 关键词: Acute; Adult; Aging; Animal Model; Attenuated; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cause of Death; Cessation of life; Chronic; Communication; Contractile Proteins; Cyclic AMP-Dependent Protein Kinases; Data; Detection; Deterioration; Dose; Energy-Generating Resources; Foundations; Functional disorder; Gene Transfer; Generations; Goals; Health; Heart; Heart Diseases; Heart failure; Human; Impairment; Lead; Link; Microfilaments; Mitochondria; Modification; Molecular; Mus; Muscle Cells; Mutation; Myocardial; Myocardial dysfunction; Oxidative Stress; Pathway interactions; Patients; Performance; Phenotype; Phosphorylation; Physiological; Play; Post-Translational Protein Processing; Production; Protein Kinase C; Proteins; Pump; Rattus; Reactive Oxygen Species; Relaxation; Rodent; Role; Route; Sarcomeres; Signal Transduction; Stimulus; Stress; Structure; Testing; Therapeutic; Thin Filament; Transgenic Mice; Troponin I; United States; Work; age group; base; beta-adrenergic receptor; blood pump; experimental study; heart function; improved; in vivo; innovation; insight; mimetics; novel; pressure; prevent; response; stressor; therapeutic evaluation; young adult

ABSTRACT Heart disease remains the leading cause of death in the United States. Patients and animal models of heart failure consistently develop elevated protein kinase C activity and downstream phosphorylation of the myofilament molecular switch protein, cardiac troponin I (cTnI) at Ser43/45 (S43/45). Previously, we showed contractile dysfunction is linked to chronic phosphorylation of this cTnI cluster and it impairs both contraction and relaxation in isolated myocytes. The working hypothesis guiding this application is that cTnI p-S43/45 is a master brake for short-term modulation of steady state function, but chronically it causes cardiac dysfunction, and serves a non-traditional role as a sarcomere stress signal. This type of sarcomere stress communicates with mitochondria to activate reactive oxygen species production and initiate mitochondrial remodeling prior to significant contractile dysfunction. This communication lays the foundation for the progressive downward spiral of cardiac dysfunction and remodeling that leads to heart failure The objectives are to demonstrate cTnIS43/45 acts as a rapid in vivo master brake, causes dose-dependent contractile dysfunction under chronic conditions and also communicates sarcomere stress by causing early mitochondrial ROS production, altered energetics and remodeling. For the approach, transgenic mice with a range of phospho-mimetic cTnIS43/45D or a novel phospho-null cTnIS43/45N were generated to achieve dose-dependent replacement of endogenous cTnI. In Aim 1, in vivo and cellular cardiac structure and contractile function are integrated with analysis of myofilament and Ca2+ signaling to gain insight into the role played by this cluster. This approach will show that dose-dependent cTnIS43/45D replacement produces in vivo cardiac and myocyte dysfunction that leads to later remodeling, progressively impaired function and heart failure. Studies in this aim also will prove that prior the significant remodeling, this cluster acts as a brake on the positive inotropic and lusitropic response to β-adrenergic receptor stimulation, and in vivo replacement with cTnIS43/45N is a functionally conservative substitution. Preliminary studies show oxidative stress and downstream mitochondrial alterations develop in adult cTnIS43/45D mice prior to detection of significant dysfunction. Thus, Aim 2 examines the novel idea that cTnIS43/45D plays a non-canonical role to stimulate downstream mitochondrial reactive oxygen species (ROS) production, followed by altered energetics and remodeling as an early route for triggering progressively impaired cardiac performance. Studies in each aim also include proof-of-concept experiments to show that early targeting of cTnI and/or downstream mitochondria prevents and/or attenuates the downward spiral of dysfunction and remodeling to heart failure.

ABSTRACT Heart disease remains the leading cause of death in the United States. Patients and animal models of heart failure consistently develop elevated protein kinase C activity and downstream phosphorylation of the myofilament molecular switch protein, cardiac troponin I (cTnI) at Ser43/45 (S43/45). Previously, we showed contractile dysfunction is linked to chronic phosphorylation of this cTnI cluster and it impairs both contraction and relaxation in isolated myocytes. The working hypothesis guiding this application is that cTnI p-S43/45 is a master brake for short-term modulation of steady state function, but chronically it causes cardiac dysfunction, and serves a non-traditional role as a sarcomere stress signal. This type of sarcomere stress communicates with mitochondria to activate reactive oxygen species production and initiate mitochondrial remodeling prior to significant contractile dysfunction. This communication lays the foundation for the progressive downward spiral of cardiac dysfunction and remodeling that leads to heart failure The objectives are to demonstrate cTnIS43/45 acts as a rapid in vivo master brake, causes dose-dependent contractile dysfunction under chronic conditions and also communicates sarcomere stress by causing early mitochondrial ROS production, altered energetics and remodeling. For the approach, transgenic mice with a range of phospho-mimetic cTnIS43/45D or a novel phospho-null cTnIS43/45N were generated to achieve dose-dependent replacement of endogenous cTnI. In Aim 1, in vivo and cellular cardiac structure and contractile function are integrated with analysis of myofilament and Ca2+ signaling to gain insight into the role played by this cluster. This approach will show that dose-dependent cTnIS43/45D replacement produces in vivo cardiac and myocyte dysfunction that leads to later remodeling, progressively impaired function and heart failure. Studies in this aim also will prove that prior the significant remodeling, this cluster acts as a brake on the positive inotropic and lusitropic response to β-adrenergic receptor stimulation, and in vivo replacement with cTnIS43/45N is a functionally conservative substitution. Preliminary studies show oxidative stress and downstream mitochondrial alterations develop in adult cTnIS43/45D mice prior to detection of significant dysfunction. Thus, Aim 2 examines the novel idea that cTnIS43/45D plays a non-canonical role to stimulate downstream mitochondrial reactive oxygen species (ROS) production, followed by altered energetics and remodeling as an early route for triggering progressively impaired cardiac performance. Studies in each aim also include proof-of-concept experiments to show that early targeting of cTnI and/or downstream mitochondria prevents and/or attenuates the downward spiral of dysfunction and remodeling to heart failure.