Sex/gender differences exist in human cardiac disease resulting from many disease etoilogies including hypertension, myocardial infarction, and hypertrophic cardiomyopathy (HCM). The hearts of women with these disorders maintain, at least, adequate cardiac function whereas men typically demonstrate increased chamber dilation and wall thinning, all signs of progressively deteriorating cardiac disease. Humans with HCM caused by an autosomal dominant mutation (R403Q) in the predominant motor protein in the heart (1-myosin heavy chain) show a similar sex difference in cardiac disease progression. Like their human counterparts, male mice expressing the R403Q mutation in the heart develop HCM characterized by progressive left-ventricular dilation and cardiac dysfunction whereas females show hypertrophy without dilation or dysfunction. However, the mechanisms that underlie these differences remain unknown. Because the R403Q mutation resides in the motor protein of the cellular contractile apparatus, hearts expressing the R403Q mutation are energy deprived and that this may be due to the increased energetic cost of contraction when expressing the R403Q mutation. Therefore, the prediction is that the observed sex difference may result from the inability of male hearts to match this increased energetic demand compared to females. In support of this idea, male R403Q hearts show metabolic abnormalities consistent with an energy-deprived state. Adenosine monophosphate-activated kinase (AMPK) may be a central regulator of this sex difference because of its established role in (1) sensing changes in cellular energy state, (2) regulating mediators of energy producing pathways, and, (3) directly modifying contractile proteins by phosphorylation. Yet, no studies have systematically addressed AMPK sex dimorphisms in mice with the R403Q mutation. Therefore, the outlined experimental plan is designed to concisely test the hypothesis that male hearts do not adapt appropriately to the increase in energetic demand caused by the R403Q HCM mutation, which leads to progressively worsening cardiac dysfunction. The hypothesis to be tested is that the key mechanism that underlies this sexual dimorphism is an altered AMPK signaling axis in males compared to females. Moreover, these studies will provide a critical foundation upon which to guide future research into defining fundamental differences in metabolic and oxidative capacities of male and female hearts in order to more completely elucidate sex differences in cardiovascular disease etiology and treatment in the human population.

Public Health Relevance

Males and females respond differently to cardiac disease such that males typically show signs of worsening cardiac function and females do not. The way males and females uniquely handle the energetic deficiencies associated with cardiac disease underlies these differences. Therefore, it is of major clinical significance that the mechanistic link be determined between cardiac disease, sex/gender differences and energetic regulators in the heart. )

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL098256-05
Application #
8582068
Study Section
Special Emphasis Panel (ZRG1-CVRS-F (03))
Program Officer
Wang, Lan-Hsiang
Project Start
2010-01-01
Project End
2014-11-30
Budget Start
2013-12-01
Budget End
2014-11-30
Support Year
5
Fiscal Year
2014
Total Cost
$386,286
Indirect Cost
$125,435
Name
University of Arizona
Department
Physiology
Type
Schools of Medicine
DUNS #
806345617
City
Tucson
State
AZ
Country
United States
Zip Code
85721
Danilo, C A; Constantopoulos, E; McKee, L A et al. (2017) Bifidobacterium animalis subsp. lactis 420 mitigates the pathological impact of myocardial infarction in the mouse. Benef Microbes 8:257-269
Behunin, Samantha M; Lopez-Pier, Marissa A; Mayfield, Rachel M et al. (2016) Liver Kinase B1 complex acts as a novel modifier of myofilament function and localizes to the Z-disk in cardiac myocytes. Arch Biochem Biophys 601:32-41
Lipovka, Yulia; Konhilas, John P (2016) The complex nature of oestrogen signalling in breast cancer: enemy or ally? Biosci Rep 36:
Birch, Camille L; Behunin, Samantha M; Lopez-Pier, Marissa A et al. (2016) Sex dimorphisms of crossbridge cycling kinetics in transgenic hypertrophic cardiomyopathy mice. Am J Physiol Heart Circ Physiol 311:H125-36
Konhilas, John P; Chen, Hao; Luczak, Elizabeth et al. (2015) Diet and sex modify exercise and cardiac adaptation in the mouse. Am J Physiol Heart Circ Physiol 308:H135-45
Behunin, Samantha M; Lopez-Pier, Marissa A; Birch, Camille L et al. (2015) LKB1/Mo25/STRAD uniquely impacts sarcomeric contractile function and posttranslational modification. Biophys J 108:1484-94
Lipovka, Yulia; Konhilas, John P (2015) AMP-Activated Protein Kinase Signalling in Cancer and Cardiac Hypertrophy. Cardiovasc Pharm Open Access 4:
Lipovka, Yulia; Chen, Hao; Vagner, Josef et al. (2015) Oestrogen receptors interact with the ?-catalytic subunit of AMP-activated protein kinase. Biosci Rep 35:
Khalpey, Zain; Janardhanan, Rajesh; Konhilas, John et al. (2014) First in man: adipose-derived stromal vascular fraction cells may promote restorative cardiac function. Am J Med 127:e11-2
Chen, Hao; Perez, Jessica N; Constantopoulos, Eleni et al. (2014) A method to study the impact of chemically-induced ovarian failure on exercise capacity and cardiac adaptation in mice. J Vis Exp :

Showing the most recent 10 out of 18 publications