Role of Cardiac Myocyte-Specific Deletion of Ataxia Telangiectasia-Mutated Kinase in Heart Function
Faculty Mentor
Suman Dalal
Mentor Home Department
Department of Health Sciences
Short Abstract
Role of Cardiac Myocyte-Specific Deletion of Ataxia Telangiectasia-Mutated Kinase in Heart Function Abbey Laughlin1, Krishna Singh2,3,4, Suman Dalal1,2,3 1Department of Health Sciences, College of Public Health, 2Department of Biomedical Sciences, James H Quillen College of Medicine, 3Center of Excellence for Inflammation, Infectious Disease and Immunity, East Tennessee State University Johnson City, TN 37614, 4James H Quillen Veterans Affairs Medical Center, Mountain Home, TN 37684 Background: Ataxia Telangiectasia-Mutated Kinase (ATM) is a serine/threonine kinase crucial in DNA repair. Individuals with mutations in the ATM gene develop a rare autosomal disease known as Ataxia-telangiectasia (A-T). A-T is characterized by multiorgan system dysfunction which may include cardiovascular, immune, endocrine, and neurological abnormalities. Previous work has shown that whole-body ATM knockout (KO) mice die between 2 to 4 months of age due to thymic lymphoma. M-mode echocardiography showed that 2-month-old ATM KO mice exhibit reduced left ventricular (LV) dilation with no significant change in percent fractional shortening (%FS) and ejection fraction (%EF) versus their wild-type counterparts. Objective: This study aims to examine if cardiac myocyte-specific deletion of ATM induces LV dilation and cardiac dysfunction. Methods: ATM flox/flox (129-Atmtm2.1Fwa/J, strain# 021444) and αMyHC-cre (Myh6-cre, strain# 011038) mice, obtained from Jackson Laboratory, were crossbred to generate cardiac myocyte-specific ATM knockout mice. All mice were genotyped by PCR using primers suggested by the Jackson Laboratory. ATM flox/flox+αMyHC-cre (fl/fl/cre) served as an experimental group with cardiac myocyte-specific deletion of ATM, while ATM flox/flox (fl/fl) and αMyHC-cre (MHC) mice served as control groups. LV diameters and heart function were measured in all groups at 1- and 4-month of age using echocardiography. Results: Analysis of M-mode echocardiographic images showed significant increase in LV end diastolic diameter in fl/fl/cre versus fl/fl in mice aged 4 months. However, %FS and %EF remained unchanged at both time points among the groups. Conclusion: Cardiac myocyte-specific deletion of ATM affects LV dilation with no effect on systolic function in mice. Future studies are forthcoming to investigate if cardiac myocyte-specific deletion of ATM affects structural and functional parameters of the heart in older (>4 months of age) cohorts of mice. This research was supported by the Department of Health Sciences and the Department of Biomedical Sciences.
Category
Science, Technology, and Engineering
Start Date
5-4-2024 8:00 AM
End Date
5-4-2024 9:00 AM
Location
D.P. Culp Center Room 272 (East Tennessee Room)
Role of Cardiac Myocyte-Specific Deletion of Ataxia Telangiectasia-Mutated Kinase in Heart Function
D.P. Culp Center Room 272 (East Tennessee Room)
Role of Cardiac Myocyte-Specific Deletion of Ataxia Telangiectasia-Mutated Kinase in Heart Function Abbey Laughlin1, Krishna Singh2,3,4, Suman Dalal1,2,3 1Department of Health Sciences, College of Public Health, 2Department of Biomedical Sciences, James H Quillen College of Medicine, 3Center of Excellence for Inflammation, Infectious Disease and Immunity, East Tennessee State University Johnson City, TN 37614, 4James H Quillen Veterans Affairs Medical Center, Mountain Home, TN 37684 Background: Ataxia Telangiectasia-Mutated Kinase (ATM) is a serine/threonine kinase crucial in DNA repair. Individuals with mutations in the ATM gene develop a rare autosomal disease known as Ataxia-telangiectasia (A-T). A-T is characterized by multiorgan system dysfunction which may include cardiovascular, immune, endocrine, and neurological abnormalities. Previous work has shown that whole-body ATM knockout (KO) mice die between 2 to 4 months of age due to thymic lymphoma. M-mode echocardiography showed that 2-month-old ATM KO mice exhibit reduced left ventricular (LV) dilation with no significant change in percent fractional shortening (%FS) and ejection fraction (%EF) versus their wild-type counterparts. Objective: This study aims to examine if cardiac myocyte-specific deletion of ATM induces LV dilation and cardiac dysfunction. Methods: ATM flox/flox (129-Atmtm2.1Fwa/J, strain# 021444) and αMyHC-cre (Myh6-cre, strain# 011038) mice, obtained from Jackson Laboratory, were crossbred to generate cardiac myocyte-specific ATM knockout mice. All mice were genotyped by PCR using primers suggested by the Jackson Laboratory. ATM flox/flox+αMyHC-cre (fl/fl/cre) served as an experimental group with cardiac myocyte-specific deletion of ATM, while ATM flox/flox (fl/fl) and αMyHC-cre (MHC) mice served as control groups. LV diameters and heart function were measured in all groups at 1- and 4-month of age using echocardiography. Results: Analysis of M-mode echocardiographic images showed significant increase in LV end diastolic diameter in fl/fl/cre versus fl/fl in mice aged 4 months. However, %FS and %EF remained unchanged at both time points among the groups. Conclusion: Cardiac myocyte-specific deletion of ATM affects LV dilation with no effect on systolic function in mice. Future studies are forthcoming to investigate if cardiac myocyte-specific deletion of ATM affects structural and functional parameters of the heart in older (>4 months of age) cohorts of mice. This research was supported by the Department of Health Sciences and the Department of Biomedical Sciences.