1
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Sun B, Rouzbehani OM, Kramer RJ, Ghosh R, Perelli RM, Atkins S, Fatahian AN, Davis K, Szulik MW, Goodman MA, Hathaway MA, Chi E, Word TA, Tunuguntla H, Denfield SW, Wehrens XHT, Whitehead KJ, Abdelnasser HY, Warren JS, Wu M, Franklin S, Boudina S, Landstrom AP. Nonsense Variant PRDM16-Q187X Causes Impaired Myocardial Development and TGF-β Signaling Resulting in Noncompaction Cardiomyopathy in Humans and Mice. Circ Heart Fail 2023; 16:e010351. [PMID: 38113297 PMCID: PMC10752244 DOI: 10.1161/circheartfailure.122.010351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 09/29/2023] [Indexed: 12/21/2023]
Abstract
BACKGROUND PRDM16 plays a role in myocardial development through TGF-β (transforming growth factor-beta) signaling. Recent evidence suggests that loss of PRDM16 expression is associated with cardiomyopathy development in mice, although its role in human cardiomyopathy development is unclear. This study aims to determine the impact of PRDM16 loss-of-function variants on cardiomyopathy in humans. METHODS Individuals with PRDM16 variants were identified and consented. Induced pluripotent stem cell-derived cardiomyocytes were generated from a proband hosting a Q187X nonsense variant as an in vitro model and underwent proliferative and transcriptional analyses. CRISPR (clustered regularly interspaced short palindromic repeats)-mediated knock-in mouse model hosting the Prdm16Q187X allele was generated and subjected to ECG, histological, and transcriptional analysis. RESULTS We report 2 probands with loss-of-function PRDM16 variants and pediatric left ventricular noncompaction cardiomyopathy. One proband hosts a PRDM16-Q187X variant with left ventricular noncompaction cardiomyopathy and demonstrated infant-onset heart failure, which was selected for further study. Induced pluripotent stem cell-derived cardiomyocytes prepared from the PRDM16-Q187X proband demonstrated a statistically significant impairment in myocyte proliferation and increased apoptosis associated with transcriptional dysregulation of genes implicated in cardiac maturation, including TGF-β-associated transcripts. Homozygous Prdm16Q187X/Q187X mice demonstrated an underdeveloped compact myocardium and were embryonically lethal. Heterozygous Prdm16Q187X/WT mice demonstrated significantly smaller ventricular dimensions, heightened fibrosis, and age-dependent loss of TGF-β expression. Mechanistic studies were undertaken in H9c2 cardiomyoblasts to show that PRDM16 binds TGFB3 promoter and represses its transcription. CONCLUSIONS Novel loss-of-function PRDM16 variant impairs myocardial development resulting in noncompaction cardiomyopathy in humans and mice associated with altered TGF-β signaling.
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Affiliation(s)
- Bo Sun
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, United States
| | - Omid M.T. Rouzbehani
- Department of Nutrition and Integrative Physiology, Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Ryan J. Kramer
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, United States
| | - Rajeshwary Ghosh
- Department of Nutrition and Integrative Physiology, Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Robin M. Perelli
- Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, United States
| | - Sage Atkins
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, United States
| | - Amir Nima Fatahian
- Department of Nutrition and Integrative Physiology, Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Kathryn Davis
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Marta W. Szulik
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Michael A. Goodman
- Department of Nutrition and Integrative Physiology, Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Marissa A. Hathaway
- Department of Nutrition and Integrative Physiology, Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Ellenor Chi
- Department of Nutrition and Integrative Physiology, Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Tarah A. Word
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, Texas, United States
| | - Hari Tunuguntla
- Departments of Medicine and Pediatrics, Section of Cardiology, Baylor College of Medicine, Houston, Texas, United States
| | - Susan W. Denfield
- Departments of Medicine and Pediatrics, Section of Cardiology, Baylor College of Medicine, Houston, Texas, United States
| | - Xander H. T. Wehrens
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, Texas, United States
- Departments of Medicine and Pediatrics, Section of Cardiology, Baylor College of Medicine, Houston, Texas, United States
- Departments of Neuroscience, Cardiovascular Research Institute, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States
| | - Kevin J. Whitehead
- Division Cardiovascular Medicine, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah, United States
| | - Hala Y. Abdelnasser
- Department of Pharmacological and Pharmaceutical Sciences, The University of Houston College of Pharmacy, Houston, Texas, United States
| | - Junco S. Warren
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
- Division of Cardiovascular Medicine, University of Utah School of Medicine, Salt Lake City, Utah, United States
| | - Mingfu Wu
- Department of Pharmacological and Pharmaceutical Sciences, The University of Houston College of Pharmacy, Houston, Texas, United States
| | - Sarah Franklin
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah
| | - Sihem Boudina
- Department of Nutrition and Integrative Physiology, Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Andrew P. Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, United States
- Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, United States
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2
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Holmes JB, Lemieux ME, Stelzer JE. Torsional and strain dysfunction precede overt heart failure in a mouse model of dilated cardiomyopathy pathogenesis. Am J Physiol Heart Circ Physiol 2023; 325:H449-H467. [PMID: 37417875 PMCID: PMC10538988 DOI: 10.1152/ajpheart.00130.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 05/24/2023] [Accepted: 06/28/2023] [Indexed: 07/08/2023]
Abstract
Detailed assessments of whole heart mechanics are crucial for understanding the consequences of sarcomere perturbations that lead to cardiomyopathy in mice. Echocardiography offers an accessible and cost-effective method of obtaining metrics of cardiac function, but the most routine imaging and analysis protocols might not identify subtle mechanical deficiencies. This study aims to use advanced echocardiography imaging and analysis techniques to identify previously unappreciated mechanical deficiencies in a mouse model of dilated cardiomyopathy (DCM) before the onset of overt systolic heart failure (HF). Mice lacking muscle LIM protein expression (MLP-/-) were used to model DCM-linked HF pathogenesis. Left ventricular (LV) function of MLP-/- and wild-type (WT) controls were studied at 3, 6, and 10 wk of age using conventional and four-dimensional (4-D) echocardiography, followed by speckle-tracking analysis to assess torsional and strain mechanics. Mice were also studied with RNA-seq. Although 3-wk-old MLP-/- mice showed normal LV ejection fraction (LVEF), these mice displayed abnormal torsional and strain mechanics alongside reduced β-adrenergic reserve. Transcriptome analysis showed that these defects preceded most molecular markers of HF. However, these markers became upregulated as MLP-/- mice aged and developed overt systolic dysfunction. These findings indicate that subtle deficiencies in LV mechanics, undetected by LVEF and conventional molecular markers, may act as pathogenic stimuli in DCM-linked HF. Using these analyses in future studies will further help connect in vitro measurements of the sarcomere function to whole heart function.NEW & NOTEWORTHY A detailed study of how perturbations to sarcomere proteins impact whole heart mechanics in mouse models is a major yet challenging step in furthering our understanding of cardiovascular pathophysiology. This study uses advanced echocardiographic imaging and analysis techniques to reveal previously unappreciated subclinical whole heart mechanical defects in a mouse model of cardiomyopathy. In doing so, it offers an accessible set of measurements for future studies to use when connecting sarcomere and whole heart function.
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Affiliation(s)
- Joshua B Holmes
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, United States
| | | | - Julian E Stelzer
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, United States
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3
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de Castro Nobre AC, Pimentel CF, do Rêgo GMS, Paludo GR, Pereira Neto GB, de Castro MB, Nitz N, Hecht M, Dallago B, Hagström L. Insights from the use of erythropoietin in experimental Chagas disease. Int J Parasitol Drugs Drug Resist 2022; 19:65-80. [PMID: 35772309 PMCID: PMC9253553 DOI: 10.1016/j.ijpddr.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 05/26/2022] [Accepted: 05/31/2022] [Indexed: 11/23/2022]
Abstract
In addition to the long-established role in erythropoiesis, erythropoietin (Epo) has protective functions in a variety of tissues, including the heart. This is the most affected organ in chronic Chagas disease, caused by the protozoan Trypanosoma cruzi. Despite seven million people being infected with T. cruzi worldwide, there is no effective treatment preventing the disease progression to the chronic phase when the pathological involvement of the heart is often observed. Chronic chagasic cardiomyopathy has a wide variety of manifestations, like left ventricular systolic dysfunction, dilated cardiomyopathy, and heart failure. Since Epo may help maintain cardiac function by reducing myocardial necrosis, inflammation, and fibrosis, this study aimed to evaluate whether the Epo has positive effects on experimental Chagas disease. For that, we assessed the earlier (acute phase) and also the later (chronic phase) use of Epo in infected C57BL/6 mice. Blood cell count, biochemical parameters, parasitic load, and echocardiography data were evaluated. In addition, histopathological analysis was carried out. Our data showed that Epo had no trypanocide effect nor did it modify the production of anti-T. cruzi antibodies. Epo-treated groups exhibited parasitic burden much lower in the heart compared to blood. No pattern of hematological changes was observed combining infection with treatment with Epo. Chronic Epo administration reduced CK-MB serum activity from d0 to d180, irrespectively of T. cruzi infection. Likewise, echocardiography and histological results indicate that Epo treatment is more effective in the chronic phase of experimental Chagas disease. Since treatment is one of the greatest challenges of Chagas disease, alternative therapies should be investigated, including Epo combined with benznidazole.
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Affiliation(s)
| | - Carlos Fernando Pimentel
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasília, Brazil
| | - George Magno Sousa do Rêgo
- Laboratory of Veterinary Clinical Pathology, Faculty of Agronomy and Veterinary Medicine, University of Brasília, Brasília, Brazil
| | - Giane Regina Paludo
- Laboratory of Veterinary Clinical Pathology, Faculty of Agronomy and Veterinary Medicine, University of Brasília, Brasília, Brazil
| | - Glaucia Bueno Pereira Neto
- Veterinary Hospital, Faculty of Agronomy and Veterinary Medicine, University of Brasília, Brasília, Brazil
| | - Márcio Botelho de Castro
- Laboratory of Veterinary Pathology, Faculty of Agronomy and Veterinary Medicine, University of Brasília, Brasília, Brazil
| | - Nadjar Nitz
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasília, Brazil
| | - Mariana Hecht
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasília, Brazil
| | - Bruno Dallago
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasília, Brazil; Veterinary Hospital, Faculty of Agronomy and Veterinary Medicine, University of Brasília, Brasília, Brazil
| | - Luciana Hagström
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasília, Brazil; Faculty of Physical Education, University of Brasília, Brasília, Brazil.
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4
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Bang ML, Bogomolovas J, Chen J. Understanding the molecular basis of cardiomyopathy. Am J Physiol Heart Circ Physiol 2022; 322:H181-H233. [PMID: 34797172 PMCID: PMC8759964 DOI: 10.1152/ajpheart.00562.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/03/2023]
Abstract
Inherited cardiomyopathies are a major cause of mortality and morbidity worldwide and can be caused by mutations in a wide range of proteins located in different cellular compartments. The present review is based on Dr. Ju Chen's 2021 Robert M. Berne Distinguished Lectureship of the American Physiological Society Cardiovascular Section, in which he provided an overview of the current knowledge on the cardiomyopathy-associated proteins that have been studied in his laboratory. The review provides a general summary of the proteins in different compartments of cardiomyocytes associated with cardiomyopathies, with specific focus on the proteins that have been studied in Dr. Chen's laboratory.
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Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research (IRGB), National Research Council (CNR), Milan Unit, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano (Milan), Italy
| | - Julius Bogomolovas
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
| | - Ju Chen
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
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5
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The p.(Cys150Tyr) variant in CSRP3 is associated with late-onset hypertrophic cardiomyopathy in heterozygous individuals. Eur J Med Genet 2020; 63:104079. [PMID: 33035702 DOI: 10.1016/j.ejmg.2020.104079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 09/06/2020] [Accepted: 09/29/2020] [Indexed: 01/25/2023]
Abstract
INTRODUCTION AND OBJECTIVES Up to 50% of patients with hypertrophic cardiomyopathy (HCM) show no disease-causing variants in genetic studies. Mutations in CSRP3 have been associated with HCM, but evidence supporting pathogenicity is inconclusive. In this study, we describe an HCM cohort with a missense variant in CSRP3 (p.Cys150Tyr) with supporting evidence for pathogenicity and a description of the associated phenotype. METHODS CSRP3 was sequenced in 6456 index cases with a diagnosis of HCM and in 5012 probands with other cardiomyopathies. In addition, 3372 index cases with hereditary cardiovascular disorders other than cardiomyopathies (mainly channelopathies and aortopathies) were used as controls. RESULTS The p.(Cys150Tyr) variant was identified in 11 unrelated individuals of the 6456 HCM probands, and it was not identified in patients with other cardiomyopathies (p < 0.0001) or in our control population (p < 0.0001). Ten of the index cases were heterozygous and one was homozygous. Homozygous had a more severe phenotype. Family screening identified 17 other carriers. Wild-type individuals showed no signs of disease. The mean age at diagnosis of affected individuals was 55 ± 13 years, and the mean left ventricular wall thickness was 18 ± 3 mm. The variant showed highly age-dependent penetrance. After a mean follow-up of 11 (±8) years, no adverse events were reported in any of the HCM patients. CONCLUSIONS The p.(Cys150Tyr) variant in CSRP3 causes late-onset and low risk form of hypertrophic cardiomyopathy in heterozygous carriers.
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6
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Zhai C, Djimsa BA, Prenni JE, Woerner DR, Belk KE, Nair MN. Tandem mass tag labeling to characterize muscle-specific proteome changes in beef during early postmortem period. J Proteomics 2020; 222:103794. [DOI: 10.1016/j.jprot.2020.103794] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 04/15/2020] [Accepted: 04/20/2020] [Indexed: 02/06/2023]
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7
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Nielsen NR, Rangarajan KV, Mao L, Rockman HA, Caron KM. A murine model of increased coronary sinus pressure induces myocardial edema with cardiac lymphatic dilation and fibrosis. Am J Physiol Heart Circ Physiol 2020; 318:H895-H907. [PMID: 32142379 DOI: 10.1152/ajpheart.00436.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Myocardial edema is a consequence of many cardiovascular stressors, including myocardial infarction, cardiac bypass surgery, and hypertension. The aim of this study was to establish a murine model of myocardial edema and elucidate the response of cardiac lymphatics and the myocardium. Myocardial edema without infarction was induced in mice by cauterizing the coronary sinus, increasing pressure in the coronary venous system, and inducing myocardial edema. In male mice, there was rapid development of edema 3 h following coronary sinus cauterization (CSC), with associated dilation of cardiac lymphatics. By 24 h, males displayed significant cardiovascular contractile dysfunction. In contrast, female mice exhibited a temporal delay in the formation of myocardial edema, with onset of cardiovascular dysfunction by 24 h. Furthermore, myocardial edema induced a ring of fibrosis around the epicardial surface of the left ventricle in both sexes that included fibroblasts, immune cells, and increased lymphatics. Interestingly, the pattern of fibrosis and the cells that make up the fibrotic epicardial ring differ between sexes. We conclude that a novel surgical model of myocardial edema without infarct was established in mice. Cardiac lymphatics compensated by exhibiting both an acute dilatory and chronic growth response. Transient myocardial edema was sufficient to induce a robust epicardial fibrotic and inflammatory response, with distinct sex differences, which underscores the sex-dependent differences that exist in cardiac vascular physiology.NEW & NOTEWORTHY Myocardial edema is a consequence of many cardiovascular stressors, including myocardial infarction, cardiac bypass surgery, and high blood pressure. Cardiac lymphatics regulate interstitial fluid balance and, in a myocardial infarction model, have been shown to be therapeutically targetable by increasing heart function. Cardiac lymphatics have only rarely been studied in a noninfarct setting in the heart, and so we characterized the first murine model of increased coronary sinus pressure to induce myocardial edema, demonstrating distinct sex differences in the response to myocardial edema. The temporal pattern of myocardial edema induction and resolution is different between males and females, underscoring sex-dependent differences in the response to myocardial edema. This model provides an important platform for future research in cardiovascular and lymphatic fields with the potential to develop therapeutic interventions for many common cardiovascular diseases.
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Affiliation(s)
- Natalie R Nielsen
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill Chapel Hill, North Carolina
| | - Krsna V Rangarajan
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill Chapel Hill, North Carolina
| | - Lan Mao
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Howard A Rockman
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Kathleen M Caron
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill Chapel Hill, North Carolina
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8
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Li J, Gresham KS, Mamidi R, Doh CY, Wan X, Deschenes I, Stelzer JE. Sarcomere-based genetic enhancement of systolic cardiac function in a murine model of dilated cardiomyopathy. Int J Cardiol 2018; 273:168-176. [PMID: 30279005 DOI: 10.1016/j.ijcard.2018.09.073] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/27/2018] [Accepted: 09/20/2018] [Indexed: 01/28/2023]
Abstract
Diminished cardiac contractile function is a characteristic feature of dilated cardiomyopathy (DCM) and many other heart failure (HF) causing etiologies. We tested the hypothesis that targeting the sarcomere to increase cardiac contractility can effectively prevent the DCM phenotype in muscle-LIM protein knockout (MLP-/-) mice. The ablation of cardiac myosin binding protein C (MYBPC3-/-) protected the MLP-/- mice from developing the DCM phenotype. We examined the in vivo cardiac function and morphology of the resultant mouse model lacking both MLP and MYBPC3 (DKO) by echocardiography and pressure-volume catheterization and found a significant reduction in hypertrophy, as evidenced by normalized wall thickness and chamber dimensions, and improved systolic function, as evidenced by enhanced ejection fraction (~26% increase compared MLP-/- mice) and rate of pressure development (DKO 7851.0 ± 504.8 vs. MLP-/- 4496.4 ± 196.8 mmHg/s). To investigate the molecular basis for the improved DKO phenotype we performed mechanical experiments in skinned myocardium isolated from WT and the individual KO mice. Skinned myocardium isolated from DKO mice displayed increased Ca2+ sensitivity of force generation, and significantly accelerated rate of cross-bridge detachment (+63% compared to MLP-/-) and rate of XB recruitment (+58% compared to MLP-/-) at submaximal Ca2+ activations. The in vivo and in vitro functional enhancement of DKO mice demonstrates that enhancing the sarcomeric contractility can be cardioprotective in HF characterized by reduced cardiac output, such as in cases of DCM.
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Affiliation(s)
- Jiayang Li
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Kenneth S Gresham
- Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States of America
| | - Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Chang Yoon Doh
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Xiaoping Wan
- The Heart and Vascular Research Center, Metro Health, Cleveland, OH, United States of America
| | - Isabelle Deschenes
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America; The Heart and Vascular Research Center, Metro Health, Cleveland, OH, United States of America
| | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America.
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9
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Ehsan M, Jiang H, L Thomson K, Gehmlich K. When signalling goes wrong: pathogenic variants in structural and signalling proteins causing cardiomyopathies. J Muscle Res Cell Motil 2017; 38:303-316. [PMID: 29119312 PMCID: PMC5742121 DOI: 10.1007/s10974-017-9487-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/28/2017] [Indexed: 12/20/2022]
Abstract
Cardiomyopathies are a diverse group of cardiac disorders with distinct phenotypes, depending on the proteins and pathways affected. A substantial proportion of cardiomyopathies are inherited and those will be the focus of this review article. With the wide application of high-throughput sequencing in the practice of clinical genetics, the roles of novel genes in cardiomyopathies are recognised. Here, we focus on a subgroup of cardiomyopathy genes [TTN, FHL1, CSRP3, FLNC and PLN, coding for Titin, Four and a Half LIM domain 1, Muscle LIM Protein, Filamin C and Phospholamban, respectively], which, despite their diverse biological functions, all have important signalling functions in the heart, suggesting that disturbances in signalling networks can contribute to cardiomyopathies.
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Affiliation(s)
- Mehroz Ehsan
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - He Jiang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Kate L Thomson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK.
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10
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Bang ML. Animal Models of Congenital Cardiomyopathies Associated With Mutations in Z-Line Proteins. J Cell Physiol 2016; 232:38-52. [PMID: 27171814 DOI: 10.1002/jcp.25424] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/10/2016] [Indexed: 01/15/2023]
Abstract
The cardiac Z-line at the boundary between sarcomeres is a multiprotein complex connecting the contractile apparatus with the cytoskeleton and the extracellular matrix. The Z-line is important for efficient force generation and transmission as well as the maintenance of structural stability and integrity. Furthermore, it is a nodal point for intracellular signaling, in particular mechanosensing and mechanotransduction. Mutations in various genes encoding Z-line proteins have been associated with different cardiomyopathies, including dilated cardiomyopathy, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, restrictive cardiomyopathy, and left ventricular noncompaction, and mutations even within the same gene can cause widely different pathologies. Animal models have contributed to a great advancement in the understanding of the physiological function of Z-line proteins and the pathways leading from mutations in Z-line proteins to cardiomyopathy, although genotype-phenotype prediction remains a great challenge. This review presents an overview of the currently available animal models for Z-line and Z-line associated proteins involved in human cardiomyopathies with special emphasis on knock-in and transgenic mouse models recapitulating the clinical phenotypes of human cardiomyopathy patients carrying mutations in Z-line proteins. Pros and cons of mouse models will be discussed and a future outlook will be given. J. Cell. Physiol. 232: 38-52, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research, UOS Milan, National Research Council and Humanitas Clinical and Research Center, Rozzano, Milan, Italy.
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11
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Xu W, Barrientos T, Mao L, Rockman HA, Sauve AA, Andrews NC. Lethal Cardiomyopathy in Mice Lacking Transferrin Receptor in the Heart. Cell Rep 2015; 13:533-545. [PMID: 26456827 DOI: 10.1016/j.celrep.2015.09.023] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 08/21/2015] [Accepted: 09/04/2015] [Indexed: 01/26/2023] Open
Abstract
Both iron overload and iron deficiency have been associated with cardiomyopathy and heart failure, but cardiac iron utilization is incompletely understood. We hypothesized that the transferrin receptor (Tfr1) might play a role in cardiac iron uptake and used gene targeting to examine the role of Tfr1 in vivo. Surprisingly, we found that decreased iron, due to inactivation of Tfr1, was associated with severe cardiac consequences. Mice lacking Tfr1 in the heart died in the second week of life and had cardiomegaly, poor cardiac function, failure of mitochondrial respiration, and ineffective mitophagy. The phenotype could only be rescued by aggressive iron therapy, but it was ameliorated by administration of nicotinamide riboside, an NAD precursor. Our findings underscore the importance of both Tfr1 and iron in the heart, and may inform therapy for patients with heart failure.
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Affiliation(s)
- Wenjing Xu
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Duke University, Durham, NC 27705, USA
| | - Tomasa Barrientos
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Duke University, Durham, NC 27705, USA
| | - Lan Mao
- Department of Medicine, Duke University School of Medicine, Duke University, Durham, NC 27705, USA
| | - Howard A Rockman
- Department of Medicine, Duke University School of Medicine, Duke University, Durham, NC 27705, USA
| | - Anthony A Sauve
- Department of Pharmacology, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
| | - Nancy C Andrews
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Duke University, Durham, NC 27705, USA; Department of Pediatrics, Duke University School of Medicine, Duke University, Durham, NC 27705, USA.
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12
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Vafiadaki E, Arvanitis DA, Sanoudou D. Muscle LIM Protein: Master regulator of cardiac and skeletal muscle functions. Gene 2015; 566:1-7. [PMID: 25936993 PMCID: PMC6660132 DOI: 10.1016/j.gene.2015.04.077] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/21/2015] [Accepted: 04/27/2015] [Indexed: 12/17/2022]
Abstract
Muscle LIM Protein (MLP) has emerged as a key regulator of striated muscle physiology and pathophysiology. Mutations in cysteine and glycine-rich protein 3 (CSRP3), the gene encoding MLP, are causative of human cardiomyopathies, whereas altered expression patterns are observed in human failing heart and skeletal myopathies. In vitro and in vivo evidences reveal a complex and diverse functional role of MLP in striated muscle, which is determined by its multiple interacting partners and subcellular distribution. Experimental evidence suggests that MLP is implicated in both myogenic differentiation and myocyte cytoarchitecture, although the full spectrum of its intracellular roles still unfolds.
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Affiliation(s)
- Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Greece
| | - Demetrios A Arvanitis
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Greece
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Greece; 4th Department of Internal Medicine, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Greece.
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13
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Michaelides M, Georgiadou S, Constantinides C. In vivo epicardial force and strain characterisation in normal and MLP-knockout murine hearts. Physiol Meas 2015; 36:1573-90. [PMID: 26057415 DOI: 10.1088/0967-3334/36/7/1573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The study's objective is to quantify in vivo epicardial force and strain in the normal and transgenic myocardium using microsensors.Male mice (n = 39), including C57BL/6 (n = 26), 129/Sv (n = 5), wild-type (WT) C57 × 129Sv (n = 5), and muscle LIM protein (MLP) knock-out (n = 3), were studied under 1.5% isoflurane anaesthesia. Microsurgery allowed the placement of two piezoelectric crystals at longitudinal epicardial loci at the basal, middle, and apical LV regions, and the independent (and/or concurrent) placement of a cantilever force sensor. The findings demonstrate longitudinal contractile and relaxation strains that ranged between 4.8-9.3% in the basal, middle, and apical regions of C57BL/6 mice, and in the mid-ventricular regions of 129/Sv, WT, and MLP mice. Measured forces ranged between 3.1-8.9 mN. The technique's feasibility is also demonstrated in normal mice following afterload, occlusion-reperfusion challenges.Furthermore, the total mid-ventricular forces developed in MLP mice were significantly reduced compared to the WT controls (5.9 ± 0.4 versus 8.9 ± 0.2 mN, p < 0.0001), possibly owing to the fibrotic and stiffer myocardium. No significant strain differences were noted between WT and MLP mice.The possibility of quantifying in vivo force and strain from the normal murine heart is demonstrated with a potential usefulness in the characterisation of transgenic and diseased mice, where regional myocardial function may be significantly altered.
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Affiliation(s)
- M Michaelides
- Department of Mechanical and Manufacturing Engineering, School of Engineering, University of Cyprus, Nicosia, Cyprus. Lecturer, Department of Sport and Exercise Science, UCLan Cyprus, University Avenue 12-14, Pyla 7080, Cyprus
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14
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High-throughput phenotypic assessment of cardiac physiology in four commonly used inbred mouse strains. J Comp Physiol B 2014; 184:763-75. [PMID: 24788387 DOI: 10.1007/s00360-014-0830-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 03/25/2014] [Accepted: 04/01/2014] [Indexed: 01/19/2023]
Abstract
Mice with genetic alterations are used in heart research as model systems of human diseases. In the last decade there was a marked increase in the recognition of genetic diversity within inbred mouse strains. Increasing numbers of inbred mouse strains and substrains and analytical variation of cardiac phenotyping methods require reproducible, high-throughput methods to standardize murine cardiovascular physiology. We describe methods for non-invasive, reliable, easy and fast to perform echocardiography and electrocardiography on awake mice. This method can be used for primary screening of the murine cardiovascular system in large-scale analysis. We provide insights into the physiological divergence of C57BL/6N, C57BL/6J, C3HeB/FeJ and 129P2/OlaHsd mouse hearts and define the expected normal values. Our report highlights that compared to the other three strains tested C57BL/6N hearts reveal features of heart failure such as hypertrophy and reduced contractile function. We found several features of the mouse ECG to be under genetic control and obtained several strain-specific differences in cardiac structure and function.
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Fayssoil A, Renault G, Guerchet N, Marchiol-Fournigault C, Fougerousse F, Richard I. Cardiac Characterization of sgca-Null Mice Using High Resolution Echocardiography. Neurol Int 2013; 5:e22. [PMID: 24416486 PMCID: PMC3883067 DOI: 10.4081/ni.2013.e22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 08/26/2013] [Indexed: 11/23/2022] Open
Abstract
Limb-girdle muscular dystrophy 2D (LGMD2D) is an inherited myogenic disorder belonging to the group of muscular dystrophies. Sgca-null mouse is a knock-out model of LGMD2D. Little is known about cardiac phenotype characterization in this model at different ages. We conducted a prospective study to characterize cardiac sgca-null mice phenotype using high resolution Doppler echocardiography at different ages. Conventional echocardiography was performed on anesthetised mice using a Vevo 770 (Visualsonics) with 30 MHz cardiac probe. Wild Type (WT) and sgca-null mice were scanned at 13, 15 and 17 months. From M-mode, we measured interventricular septal (IVS) wall thickness, posterior wall (PW) thickness, and end-left ventricular diameter in systolic and diastolic. From the above parameters, we calculated left ventricular (LV) shortening fraction (SF), LV ejection fraction (EF) and LV mass. At age 13 months, PW diastolic thickness was increased in sgca-null mice (0.89±0.14 mm vs 0.73±0.2 mm; P=0.020) and LV mass was higher in sgca-null mice (LV mass 205.2 mg vs 143 mg; P=0.001). We found also dilation of the LV (LVEDD: 4.84 mm vs 4.29 mm; P=0.019) in sgca-null mice. At age 15 months, dilation of the LV (LVEDD: 4.86 mm vs 4 mm; P=0.05) with an increase of the LV mass (165.7 mg vs 127.12; P=0.03) are found in sgca-null mice. At age 17 months, we found a decrease of the PW thickening (17% vs 30%; P=0.036). This work provides echocardiographic insights for the assessment of pharmaceutical therapies in sgca-null mice.
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Affiliation(s)
- Abdallah Fayssoil
- Raymond Poincare Hospital, University of Versailles Saint-Quentin-en-Yvelines , Garches
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16
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Abstract
Control and modulation of electrical signaling is vital to normal physiology, particularly in neurons, cardiac myocytes, and skeletal muscle. The orchestrated activities of variable sets of ion channels and transporters, including voltage-gated ion channels (VGICs), are responsible for initiation, conduction, and termination of the action potential (AP) in excitable cells. Slight changes in VGIC activity can lead to severe pathologies including arrhythmias, epilepsies, and paralyses, while normal excitability depends on the precise tuning of the AP waveform. VGICs are heavily posttranslationally modified, with upward of 30% of the mature channel mass consisting of N- and O-glycans. These glycans are terminated typically by negatively charged sialic acid residues that modulate voltage-dependent channel gating directly. The data indicate that sialic acids alter VGIC activity in isoform-specific manners, dependent in part, on the number/location of channel sialic acids attached to the pore-forming alpha and/or auxiliary subunits that often act through saturating electrostatic mechanisms. Additionally, cell-specific regulation of sialylation can affect VGIC gating distinctly. Thus, channel sialylation is likely regulated through two mechanisms that together contribute to a dynamic spectrum of possible gating motifs: a subunit-specific mechanism and regulated (aberrant) changes in the ability of the cell to glycosylate. Recent studies showed that neuronal and cardiac excitability is modulated through regulated changes in voltage-gated Na(+) channel sialylation, suggesting that both mechanisms of differential VGIC sialylation contribute to electrical signaling in the brain and heart. Together, the data provide insight into an important and novel paradigm involved in the control and modulation of electrical signaling.
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Affiliation(s)
- Andrew R Ednie
- Programs in Cardiovascular Research and Neuroscience, Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
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17
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Tang H, Xiao K, Mao L, Rockman HA, Marchuk DA. Overexpression of TNNI3K, a cardiac-specific MAPKKK, promotes cardiac dysfunction. J Mol Cell Cardiol 2013; 54:101-11. [PMID: 23085512 PMCID: PMC3535516 DOI: 10.1016/j.yjmcc.2012.10.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/01/2012] [Accepted: 10/04/2012] [Indexed: 12/21/2022]
Abstract
Cardiac troponin I-interacting kinase (TNNI3K) is a cardiac-specific kinase whose biological function remains largely unknown. We have recently shown that TNNI3K expression greatly accelerates cardiac dysfunction in mouse models of cardiomyopathy, indicating an important role in modulating disease progression. To further investigate TNNI3K kinase activity in vivo, we have generated transgenic mice expressing both wild-type and kinase-dead versions of the human TNNI3K protein. Importantly, we show that the increased TNNI3K kinase activity induces mouse cardiac remodeling, and its kinase activity promotes accelerated disease progression in a left-ventricular pressure overload model of mouse cardiomyopathy. Using an in vitro kinase assay and proteomics analysis, we show that TNNI3K is a dual-function kinase with Tyr and Ser/Thr kinase activity. TNNI3K expression induces a series of cellular and molecular changes, including a reduction of sarcomere length and changes in titin isoform composition, which are indicative of cardiac remodeling. Using antisera to TNNI3K, we show that TNNI3K protein is located at the sarcomere Z disc. These combined data suggest that TNNI3K mediates cell signaling to modulate cardiac response to stress.
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Affiliation(s)
- Hao Tang
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710
| | - Kunhong Xiao
- Department of Medicine, Duke University, Durham, NC 27710
| | - Lan Mao
- Department of Medicine, Duke University, Durham, NC 27710
| | | | - Douglas A. Marchuk
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710
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Houser SR, Margulies KB, Murphy AM, Spinale FG, Francis GS, Prabhu SD, Rockman HA, Kass DA, Molkentin JD, Sussman MA, Koch WJ. Animal models of heart failure: a scientific statement from the American Heart Association. Circ Res 2012; 111:131-50. [PMID: 22595296 DOI: 10.1161/res.0b013e3182582523] [Citation(s) in RCA: 331] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Chang JH, Paik SY, Mao L, Eisner W, Flannery PJ, Wang L, Tang Y, Mattocks N, Hadjadj S, Goujon JM, Ruiz P, Gurley SB, Spurney RF. Diabetic kidney disease in FVB/NJ Akita mice: temporal pattern of kidney injury and urinary nephrin excretion. PLoS One 2012; 7:e33942. [PMID: 22496773 PMCID: PMC3319540 DOI: 10.1371/journal.pone.0033942] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 02/23/2012] [Indexed: 11/24/2022] Open
Abstract
Akita mice are a genetic model of type 1 diabetes. In the present studies, we investigated the phenotype of Akita mice on the FVB/NJ background and examined urinary nephrin excretion as a marker of kidney injury. Male Akita mice were compared with non-diabetic controls for functional and structural characteristics of renal and cardiac disease. Podocyte number and apoptosis as well as urinary nephrin excretion were determined in both groups. Male FVB/NJ Akita mice developed sustained hyperglycemia and albuminuria by 4 and 8 weeks of age, respectively. These abnormalities were accompanied by a significant increase in systolic blood pressure in 10-week old Akita mice, which was associated with functional, structural and molecular characteristics of cardiac hypertrophy. By 20 weeks of age, Akita mice developed a 10-fold increase in albuminuria, renal and glomerular hypertrophy and a decrease in the number of podocytes. Mild-to-moderate glomerular mesangial expansion was observed in Akita mice at 30 weeks of age. In 4-week old Akita mice, the onset of hyperglycemia was accompanied by increased podocyte apoptosis and enhanced excretion of nephrin in urine before the development of albuminuria. Urinary nephrin excretion was also significantly increased in albuminuric Akita mice at 16 and 20 weeks of age and correlated with the albumin excretion rate. These data suggest that: 1. FVB/NJ Akita mice have phenotypic characteristics that may be useful for studying the mechanisms of kidney and cardiac injury in diabetes, and 2. Enhanced urinary nephrin excretion is associated with kidney injury in FVB/NJ Akita mice and is detectable early in the disease process.
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Affiliation(s)
- Jae-Hyung Chang
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, United States of America
| | - Seung-Yeol Paik
- Chung-ang University Medical School, Seoul, Republic of Korea
| | - Lan Mao
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - William Eisner
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, United States of America
| | - Patrick J. Flannery
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, United States of America
| | - Liming Wang
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, United States of America
| | - Yuping Tang
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, United States of America
| | - Natalie Mattocks
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, United States of America
| | - Samy Hadjadj
- INSERM U927, Poitiers, France and INSERM CIC 0802, Poitiers, France and CHU Poitiers, Endocrinologie, Poitiers, France
| | - Jean-Michel Goujon
- CHU Poitiers, Pathology Unit, Poitiers, France
- INSERM U927, Poitiers, France and INSERM CIC 0802, Poitiers, France and CHU Poitiers, Endocrinologie, Poitiers, France
| | - Phillip Ruiz
- Department of Surgery and Pathology, University of Miami, Miami, Florida, United States of America
| | - Susan B. Gurley
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, United States of America
| | - Robert F. Spurney
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, United States of America
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Unsöld B, Schotola H, Jacobshagen C, Seidler T, Sossalla S, Emons J, Klede S, Knöll R, Guan K, El-Armouche A, Linke WA, Kögler H, Hasenfuss G. Age-dependent changes in contractile function and passive elastic properties of myocardium from mice lacking muscle LIM protein (MLP). Eur J Heart Fail 2012; 14:430-7. [PMID: 22371524 DOI: 10.1093/eurjhf/hfs020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Muscle LIM protein (MLP) null mice are often used as a model for human dilated cardiomyopathy. So far, little is known about the time course and pathomechanisms leading to the development of the adult phenotype. METHODS AND RESULTS We systematically analysed the contractile phenotype, myofilament calcium (Ca(2)(+)) responsiveness, passive myocardial mechanics, histology, and mRNA expression in mice aged 4 and 12 weeks. In 4-week-old animals, there was no significant difference in the force-frequency relationship (FFR) and catecholamine response of intact isolated papillary muscles between wild-type (WT) and MLP null myocardium. In 12-week-old animals, WT myocardium exhibited a significantly positive FFR, while that of MLP null mice was significantly negative, and the inotropic response to catecholamines was significantly reduced in MLP null mice. This time course of decline in contractile function was confirmed in vivo by echocardiography. Whereas at 4 weeks of age MLP null mice and WT littermates showed similar levels of SERCA2a (sarcoplasmic reticulum Ca(2+) ATPase) expression, the expression was significantly lower in 12-week-old MLP null mice compared with littermate controls. Myofilament Ca(2)(+) responsiveness was not affected by the lack of MLP, irrespective of age. Whereas in 4-week-old animals MLP null myocardium showed a trend to an increased compliance compared with the WT, myocardium of 12-week-old MLP null mice was significantly less compliant than WT myocardium. Parallel to the decrease in compliance there was an increase in fibrosis in the MLP null animals. CONCLUSION Our data suggest that MLP deficiency does not primarily influence myocardial contractility. A lack of MLP leads to an age-dependent impairment of excitation-contraction coupling with resulting contractile dysfunction and secondary fibrosis.
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Affiliation(s)
- Bernhard Unsöld
- Department of Cardiology and Pneumology, Georg-August University of Göttingen, Germany
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21
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Predictive importance of left ventricular myocardial stiffness for the prognosis of patients with congestive heart failure. J Cardiol 2011; 58:245-52. [DOI: 10.1016/j.jjcc.2011.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 06/17/2011] [Accepted: 07/07/2011] [Indexed: 11/24/2022]
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Raghavan K, Feldman MD, Porterfield JE, Larson ER, Jenkins JT, Escobedo D, Pearce JA, Valvano JW. A bio-telemetric device for measurement of left ventricular pressure-volume loops using the admittance technique in conscious, ambulatory rats. Physiol Meas 2011; 32:701-15. [PMID: 21606560 DOI: 10.1088/0967-3334/32/6/007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This paper presents the design, construction and testing of a device to measure pressure-volume loops in the left ventricle of conscious, ambulatory rats. Pressure is measured with a standard sensor, but volume is derived from data collected from a tetrapolar electrode catheter using a novel admittance technique. There are two main advantages of the admittance technique to measure volume. First, the contribution from the adjacent muscle can be instantaneously removed. Second, the admittance technique incorporates the nonlinear relationship between the electric field generated by the catheter and the blood volume. A low power instrument weighing 27 g was designed, which takes pressure-volume loops every 2 min and runs for 24 h. Pressure-volume data are transmitted wirelessly to a base station. The device was first validated on 13 rats with an acute preparation with 2D echocardiography used to measure true volume. From an accuracy standpoint, the admittance technique is superior to both the conductance technique calibrated with hypertonic saline injections, and calibrated with cuvettes. The device was then tested on six rats with 24 h chronic preparation. Stability of animal preparation and careful calibration are important factors affecting the success of the device.
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Briston SJ, Caldwell JL, Horn MA, Clarke JD, Richards MA, Greensmith DJ, Graham HK, Hall MCS, Eisner DA, Dibb KM, Trafford AW. Impaired β-adrenergic responsiveness accentuates dysfunctional excitation-contraction coupling in an ovine model of tachypacing-induced heart failure. J Physiol 2011; 589:1367-82. [PMID: 21242250 PMCID: PMC3082097 DOI: 10.1113/jphysiol.2010.203984] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 01/10/2011] [Indexed: 01/08/2023] Open
Abstract
Reduced inotropic responsiveness is characteristic of heart failure (HF). This study determined the cellular Ca2+ homeostatic and molecular mechanisms causing the blunted β-adrenergic (β-AR) response in HF.We induced HF by tachypacing in sheep; intracellular Ca2+ concentration was measured in voltage-clamped ventricular myocytes. In HF, Ca2+ transient amplitude and peak L-type Ca2+ current (ICa-L) were reduced (to 70 ± 11% and 50 ± 3.7% of control, respectively, P <0.05) whereas sarcoplasmic reticulum (SR) Ca2+ content was unchanged. β-AR stimulation with isoprenaline (ISO) increased Ca2+ transient amplitude, ICa-L and SRCa2+ content in both cell types; however, the response of HF cells was markedly diminished (P <0.05).Western blotting revealed an increase in protein phosphatase levels (PP1, 158 ± 17% and PP2A, 188 ± 34% of control, P <0.05) and reduced phosphorylation of phospholamban in HF (Ser16, 30 ± 10% and Thr17, 41 ± 15% of control, P <0.05). The β-AR receptor kinase GRK-2 was also increased in HF (173 ± 38% of control, P <0.05). In HF, activation of adenylyl cyclase with forskolin rescued the Ca2+ transient, SR Ca2+ content and SR Ca2+ uptake rate to the same levels as control cells in ISO. In conclusion, the reduced responsiveness of the myocardium to β-AR agonists in HF probably arises as a consequence of impaired phosphorylation of key intracellular proteins responsible for regulating the SR Ca2+ content and therefore failure of the systolic Ca2+ transient to increase appropriately during β-AR stimulation.
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Affiliation(s)
- Sarah J Briston
- Unit of Cardiac Physiology, Manchester Academic Health Sciences Centre, University of Manchester, Manchester M13 9NT, UK
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Hearts of surviving MLP-KO mice show transient changes of intracellular calcium handling. Mol Cell Biochem 2010; 342:251-60. [PMID: 20490897 DOI: 10.1007/s11010-010-0492-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 05/04/2010] [Indexed: 10/19/2022]
Abstract
The muscle Lim protein knock-out (MLP-KO) mouse model is extensively used for studying the pathophysiology of dilated cardiomyopathy. However, explanation is lacking for the observed long survival of the diseased mice which develop until adulthood despite the gene defect, which theoretically predestines them to early death due to heart failure. We hypothesized that adaptive changes of cardiac intracellular calcium (Ca(i)(2+)) handling might explain the phenomenon. In order to study the progression of changes in cardiac function and Ca(i)(2+) cycling, myocardial Ca(i)(2+)-transients recorded by Indo-1 surface fluorometry were assessed with concomitant measurement of hemodynamic performance in isolated Langendorff-perfused hearts of 3- and 9-month old MLP-KO animals. Hearts were challenged with beta-agonist isoproterenol and the sarcoplasmic reticular Ca(2+)-ATPase (SERCA2a) inhibitor cyclopiazonic acid (CPA). Cardiac mRNA content and levels of key Ca(2+) handling proteins were also measured. A decline in lusitropic function was observed in 3-month old, but not in 9-month old MLP-KO mice under unchallenged conditions. beta-adrenergic responses to isoproterenol were similar in all the studied groups. The CPA induced an increase in end-diastolic Ca(i)(2+)-level and a decrease in Ca(2+)-sequestration capacity in 3-month old MLP-KO mice compared to age-matched controls. This unfavorable condition was absent at 9 months of age. SERCA2a expression was lower in 3-month old MLP-KO than in the corresponding controls and in 9-month old MLP-KO hearts. Our results show time-related recovery of hemodynamic function and an age-dependent compensatory upregulation of Ca(i)(2+) handling in hearts of MLP-KO mice, which most likely involve the normalization of the expression of SERCA2a in the affected hearts.
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25
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Kim BE, Turski ML, Nose Y, Casad M, Rockman HA, Thiele DJ. Cardiac copper deficiency activates a systemic signaling mechanism that communicates with the copper acquisition and storage organs. Cell Metab 2010; 11:353-63. [PMID: 20444417 PMCID: PMC2901851 DOI: 10.1016/j.cmet.2010.04.003] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2009] [Revised: 02/05/2010] [Accepted: 04/05/2010] [Indexed: 12/15/2022]
Abstract
Copper (Cu) is an essential cofactor for a variety of metabolic functions, and the regulation of systemic Cu metabolism is critical to human health. Dietary Cu is absorbed through the intestine, stored in the liver, and mobilized into the circulation; however, systemic Cu homeostasis is poorly understood. We generated mice with a cardiac-specific knockout of the Ctr1 Cu transporter (Ctr1(hrt/hrt)), resulting in cardiac Cu deficiency and severe cardiomyopathy. Unexpectedly, Ctr1(hrt/hrt) mice exhibited increased serum Cu levels and a concomitant decrease in hepatic Cu stores. Expression of the ATP7A Cu exporter, thought to function predominantly in intestinal Cu acquisition, was strongly increased in liver and intestine of Ctr1(hrt/hrt) mice. These studies identify ATP7A as a candidate for hepatic Cu mobilization in response to peripheral tissue demand, and illuminate a systemic regulation in which the Cu status of the heart is signaled to organs that take up and store Cu.
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Affiliation(s)
- Byung-Eun Kim
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Michelle L. Turski
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Yasuhiro Nose
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Michelle Casad
- Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710
- Cell Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Howard A. Rockman
- Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710
- Cell Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Dennis J. Thiele
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
- correspondence should be addressed to D.J. Thiele ()
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Lehnart SE, Maier LS, Hasenfuss G. Abnormalities of calcium metabolism and myocardial contractility depression in the failing heart. Heart Fail Rev 2010; 14:213-24. [PMID: 19434491 PMCID: PMC2772965 DOI: 10.1007/s10741-009-9146-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Heart failure (HF) is characterized by molecular and cellular defects which jointly contribute to decreased cardiac pump function. During the development of the initial cardiac damage which leads to HF, adaptive responses activate physiological countermeasures to overcome depressed cardiac function and to maintain blood supply to vital organs in demand of nutrients. However, during the chronic course of most HF syndromes, these compensatory mechanisms are sustained beyond months and contribute to progressive maladaptive remodeling of the heart which is associated with a worse outcome. Of pathophysiological significance are mechanisms which directly control cardiac contractile function including ion- and receptor-mediated intracellular signaling pathways. Importantly, signaling cascades of stress adaptation such as intracellular calcium (Ca(2+)) and 3'-5'-cyclic adenosine monophosphate (cAMP) become dysregulated in HF directly contributing to adverse cardiac remodeling and depression of systolic and diastolic function. Here, we provide an update about Ca(2+) and cAMP dependent signaling changes in HF, how these changes affect cardiac function, and novel therapeutic strategies which directly address the signaling defects.
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Affiliation(s)
- Stephan E Lehnart
- Department of Cardiology & Pulmonology, Center of Molecular Cardiology, UMG Heart Center, Georg August University Medical School, Goettingen, Germany.
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27
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Rodgers BD, Interlichia JP, Garikipati DK, Mamidi R, Chandra M, Nelson OL, Murry CE, Santana LF. Myostatin represses physiological hypertrophy of the heart and excitation-contraction coupling. J Physiol 2009; 587:4873-86. [PMID: 19736304 DOI: 10.1113/jphysiol.2009.172544] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Although myostatin negatively regulates skeletal muscle growth, its function in heart is virtually unknown. Herein we demonstrate that it inhibits basal and IGF-stimulated proliferation and differentiation and also modulates cardiac excitation-contraction (EC) coupling. Loss of myostatin induced eccentric hypertrophy and enhanced cardiac responsiveness to beta-adrenergic stimulation in vivo. This was due to myostatin null ventricular myocytes having larger [Ca(2+)](i) transients and contractions and responding more strongly to beta-adrenergic stimulation than wild-type cells. Enhanced cardiac output and beta-adrenergic responsiveness of myostatin null mice was therefore due to increased SR Ca(2+) release during EC coupling and to physiological hypertrophy, but not to enhanced myofilament function as determined by simultaneous measurement of force and ATPase activity. Our studies support the novel concept that myostatin is a repressor of physiological cardiac muscle growth and function. Thus, the controlled inhibition of myostatin action could potentially help repair damaged cardiac muscle by inducing physiological hypertrophy.
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Affiliation(s)
- Buel D Rodgers
- Department of Animal Sciences and School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA.
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Yoo B, Lemaire A, Mangmool S, Wolf MJ, Curcio A, Mao L, Rockman HA. Beta1-adrenergic receptors stimulate cardiac contractility and CaMKII activation in vivo and enhance cardiac dysfunction following myocardial infarction. Am J Physiol Heart Circ Physiol 2009; 297:H1377-86. [PMID: 19633206 DOI: 10.1152/ajpheart.00504.2009] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The beta-adrenergic receptor (betaAR) signaling system is one of the most powerful regulators of cardiac function and a key regulator of Ca(2+) homeostasis. We investigated the role of betaAR stimulation in augmenting cardiac function and its role in the activation of Ca(2+)/calmodulin-dependent kinase II (CaMKII) using various betaAR knockouts (KO) including beta(1)ARKO, beta(2)ARKO, and beta(1)/beta(2)AR double-KO (DKO) mice. We employed a murine model of left anterior descending coronary artery ligation to examine the differential contributions of specific betaAR subtypes in the activation of CaMKII in vivo in failing myocardium. Cardiac inotropy, chronotropy, and CaMKII activity following short-term isoproterenol stimulation were significantly attenuated in beta(1)ARKO and DKO compared with either the beta(2)ARKO or wild-type (WT) mice, indicating that beta(1)ARs are required for catecholamine-induced increases in contractility and CaMKII activity. Eight weeks after myocardial infarction (MI), beta(1)ARKO and DKO mice showed a significant attenuation in fractional shortening compared with either the beta(2)ARKO or WT mice. CaMKII activity after MI was significantly increased only in the beta(2)ARKO and WT hearts and not in the beta(1)ARKO and DKO hearts. The border zone of the infarct in the beta(2)ARKO and WT hearts demonstrated significantly increased apoptosis by TUNEL staining compared with the beta(1)ARKO and DKO hearts. Taken together, these data show that cardiac function and CaMKII activity are mediated almost exclusively by the beta(1)AR. Moreover, it appears that beta(1)AR signaling is detrimental to cardiac function following MI, possibly through activation of CaMKII.
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Affiliation(s)
- ByungSu Yoo
- Departments of Medicine, Cell Biology and Molecular Genetics, Duke University Medical Center, Durham, North Carolina 27710, USA
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Fernandez L, Marchuk DA, Moran JL, Beier DR, Rockman HA. An N-ethyl-N-nitrosourea mutagenesis recessive screen identifies two candidate regions for murine cardiomyopathy that map to chromosomes 1 and 15. Mamm Genome 2009; 20:296-304. [PMID: 19387734 PMCID: PMC2743897 DOI: 10.1007/s00335-009-9184-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Accepted: 03/18/2009] [Indexed: 10/20/2022]
Abstract
N-ethyl-N-nitrosourea (ENU) mutagenesis screens have been successful for identifying genes that affect important biological processes and diseases. However, for heart-related phenotypes, these screens have been employed exclusively for developmental phenotypes, and to date no adult cardiomyopathy-causing genes have been discovered through a mutagenesis screen. To identify novel disease-causing and disease-modifying genes for cardiomyopathy, we performed an ENU recessive mutagenesis screen in adult mice. Using noninvasive echocardiography to screen for abnormalities in cardiac function, we identified a heritable cardiomyopathic phenotype in two families. To identify the chromosomal regions where the mutations are localized, we used a single nucleotide polymorphism (SNP) panel for genetic mapping of mouse mutations. This panel provided whole-genome linkage information and identified the mutagenized candidate regions at the proximal end of chromosome 1 (family EN1), and at the distal end of chromosome 15 (family EN25). We have identified 94 affected mice in family EN1 and have narrowed the candidate interval to 1 Mb. We have identified 20 affected mice in family EN25 and have narrowed the candidate interval to 12 Mb. The identification of the genes responsible for the observed phenotype in these families will be strong candidates for disease-causing or disease-modifying genes in patients with heart failure.
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Affiliation(s)
- Liliana Fernandez
- Department of Medicine, Duke University Medical Center, DUMC 3104, 226 CARL Building, Research Drive, Durham, NC 27710, USA
| | - Douglas A. Marchuk
- Department Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Jennifer L. Moran
- Genetic Analysis Platform, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - David R. Beier
- Division of Genetics, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Howard A. Rockman
- Department of Medicine, Duke University Medical Center, DUMC 3104, 226 CARL Building, Research Drive, Durham, NC 27710, USA
- Department Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
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Stypmann J, Engelen MA, Troatz C, Rothenburger M, Eckardt L, Tiemann K. Echocardiographic assessment of global left ventricular function in mice. Lab Anim 2009; 43:127-37. [DOI: 10.1258/la.2007.06001e] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Doppler-echocardiographic assessment of cardiovascular structure and function in murine models has developed into one of the most commonly used non-invasive techniques during the last decades. Recent technical improvements even expanded the possibilities. In this review, we summarize the current options to assess global left ventricular (LV) function in mice using echocardiographic techniques. In detail, standard techniques as structural and functional assessment of the cardiovascular phenotype using one-dimensional M-mode echocardiography, two-dimensional B-mode echocardiography and spectral Doppler signals from mitral inflow respective aortal outflow are presented. Further pros and contras of recently implemented techniques as three-dimensional echocardiography and strain and strain rate measurements are discussed. Deduced measures of LV function as the myocardial performance index according to Tei, estimation of the mean velocity of circumferential fibre shortening, LV wall stress and different algorithms to estimate the LV mass are described in detail. Last but not least, specific features and limitations of murine echocardiography are presented. Future perspectives in respect to new examination techniques like targeted molecular imaging with advanced ultrasound contrast bubbles or improvement of equipment like new generation matrix transducers for murine echocardiography are discussed.
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Affiliation(s)
- Jörg Stypmann
- Department of Cardiology and Angiology, Hospital of the University of Münster, Albert-Schweitzer-Str. 33, D-48149 Münster, Germany
- Interdisciplinary Centre for Clinical Research, Central Project Group (ZPG 4a), Westfälische Wilhelms Universität, Münster, Germany
- Collaborative Research Centre (SFB) 656, Project C3, Münster, Germany
| | - Markus A Engelen
- Department of Cardiology and Angiology, Hospital of the University of Münster, Albert-Schweitzer-Str. 33, D-48149 Münster, Germany
- University Medical Center Utrecht, Department of Medical Physiology, Utrecht, The Netherlands
| | - Clemens Troatz
- Collaborative Research Centre (SFB) 656, Project C3, Münster, Germany
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, University of Bonn, Bonn, Germany
| | - Markus Rothenburger
- Department of Thoracic and Cardiovascular Surgery, University Hospital, Münster, Münster, Germany
| | - Lars Eckardt
- Department of Cardiology and Angiology, Hospital of the University of Münster, Albert-Schweitzer-Str. 33, D-48149 Münster, Germany
| | - Klaus Tiemann
- Collaborative Research Centre (SFB) 656, Project C3, Münster, Germany
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, University of Bonn, Bonn, Germany
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Chronic treatment with clenbuterol modulates endothelial progenitor cells and circulating factors in a murine model of cardiomyopathy. J Cardiovasc Transl Res 2009; 2:182-90. [PMID: 20559986 DOI: 10.1007/s12265-009-9089-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Accepted: 01/27/2009] [Indexed: 10/21/2022]
Abstract
The purpose of this study was to determine the effects of chronic treatment with the beta 2 adrenergic receptor agonist clenbuterol on endothelial progenitor cells (EPC) in a well-characterized model of heart failure, the muscle LIM protein knockout (MLP(-/-)) mouse. MLP(-/-) mice were treated daily with clenbuterol (2 mg/kg) or saline subcutaneously for 6 weeks. Clenbuterol led to a 30% increase in CD31(+) cells in the bone marrow of MLP(-/-) heart failure mice (p < 0.004). Clenbuterol did not improve ejection fraction. Clenbuterol treatment in MLP(-/-) mice was associated with significant changes in the following circulating factors: tissue inhibitor of metalloproteinase-type 1, leukemia inhibitory factor 1, C-reactive protein, apolipoprotein A1, fibroblast growth factor 2, serum glutamic oxaloacetic transaminase, macrophage-derived chemokine, and monocyte chemoattractant protein-3. Clenbuterol treatment in the MLP(-/-) model of heart failure did not rescue heart function, yet did increase CD31(+) cells in the bone marrow. This is the first evidence that a beta 2 agonist increases EPC proliferation in the bone marrow in a preclinical model of heart failure.
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Chin BB, Metzler SD, Lemaire A, Curcio A, Vemulapalli S, Greer KL, Petry NA, Turkington TG, Coleman RE, Rockman H, Jaszczak RJ. Left ventricular functional assessment in mice: feasibility of high spatial and temporal resolution ECG-gated blood pool SPECT. Radiology 2007; 245:440-8. [PMID: 17940303 DOI: 10.1148/radiol.2452061973] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
PURPOSE To prospectively determine feasibility of evaluating murine left ventricular (LV) function with electrocardiographically (ECG)-gated blood pool single photon emission computed tomography (SPECT). MATERIALS AND METHODS All animal studies had institutional animal care and use committee approval. SPECT was performed with conventional time-binned acquisition (eight frames per ECG cycle) in normal mice (normal group A, n = 6) and mice with myocardial infarction (MI) (n = 8). To determine feasibility of high temporal resolution and rapid data acquisition, another group of normal mice (normal group B, n = 4) underwent imaging with conventional (eight-frame) time-binned and list-mode (LM) acquisitions. LM acquisitions were reconstructed with eight and 16 frames per ECG cycle and 10 minutes of data (short LM). SPECT images were assessed visually, and LV-to-lung background activity ratios were calculated. LV end-systolic and end-diastolic volumes were defined with a phase analysis and threshold method. LV ejection fraction (LVEF) was calculated from LV volumes and count-based methods (n = 18 mice). Fractional shortening (FS) at echocardiography defined MI dysfunction (mild MI: FS > or = 50%; severe MI: FS < 50%). Group means were compared for significant differences with analysis of variance. RESULTS ECG-gated blood pool SPECT demonstrated normal, concentric LV contraction in all normal mice (n = 10). LV-to-lung background ratio was more than 10:1 (range, 10.3-29.4; n = 18). Focal wall motion abnormalities were detected at SPECT both visually and with phase analysis in all mice with severe MI (n = 5). Mice with severe MI had significantly lower LVEF than normal group A mice (32% +/- 14 [standard deviation] vs 64% +/- 8%; P < .001). All mice with mild MI (n = 3) had normal contraction and LVEF. In paired acquisitions in normal group B mice, all reconstructions (n = 16) showed normal LV contraction. LVEF was not significantly different (P = .88) between time-binned (71% +/- 12), eight-frame LM (71% +/- 12), 16-frame LM (77% +/- 10), and short LM (73% +/- 14) reconstructions. CONCLUSION Murine LV functional assessment is feasible with high spatial and temporal resolution ECG-gated blood pool SPECT. LV dysfunction can be quantified and focal wall motion abnormalities detected in the MI model of heart failure.
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Affiliation(s)
- Bennett B Chin
- Department of Radiology, Duke University School of Medicine, Durham, NC 27710, USA.
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Esposito G, Perrino C, Ozaki T, Takaoka H, Defer N, Petretta MP, De Angelis MC, Mao L, Hanoune J, Rockman HA, Chiariello M. Increased myocardial contractility and enhanced exercise function in transgenic mice overexpressing either adenylyl cyclase 5 or 8. Basic Res Cardiol 2007; 103:22-30. [PMID: 18034275 DOI: 10.1007/s00395-007-0688-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Accepted: 10/22/2007] [Indexed: 01/08/2023]
Abstract
OBJECTIVE ss-adrenergic receptors (ssARs) are powerful regulators of cardiac function in vivo, activating heterotrimeric G proteins and the effector molecule adenylyl cyclase (AC). Interestingly, cardiac-specific overexpression of different AC isoforms leads to variable changes in cardiac function. Whether AC overexpression affects intrinsic cardiac contractility in an isoform-specific fashion determining a change in exercise capacity is currently unknown. METHODS To address this issue, we performed load-independent measurements of cardiac systolic and diastolic function by pressure-volume (PV) loop analysis in intact wild-type mice (WT) and transgenic mice overexpressing the AC isoforms 5 or 8. RESULTS Here we show that cardiac overexpression of either AC5 or AC8 transgenic mice determined an increase in intrinsic cardiac contractility. Interestingly, AC8 transgenic mice displayed a significantly greater increase in cardiac contractility and improved active phase of relaxation. Despite these differences detected by PV loop analysis, both AC5 and AC8 mice showed a marked increase in exercise capacity on treadmill testing. CONCLUSIONS Our results demonstrate that load-independent measurements of cardiac function are needed to compare different groups of genetically-modified mouse models and to detect subtle AC isoform-specific changes in cardiac performance.
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Affiliation(s)
- Giovanni Esposito
- Division of Cardiology, University Federico II of Naples, Via Pansini 5, 80131 Naples, Italy.
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Mohler PJ, Healy JA, Xue H, Puca AA, Kline CF, Rand Allingham R, Kranias EG, Rockman HA, Bennett V. Ankyrin-B syndrome: enhanced cardiac function balanced by risk of cardiac death and premature senescence. PLoS One 2007; 2:e1051. [PMID: 17940615 PMCID: PMC2013943 DOI: 10.1371/journal.pone.0001051] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 09/20/2007] [Indexed: 12/21/2022] Open
Abstract
Here we report the unexpected finding that specific human ANK2 variants represent a new example of balanced human variants. The prevalence of certain ANK2 (encodes ankyrin-B) variants range from 2 percent of European individuals to 8 percent in individuals from West Africa. Ankyrin-B variants associated with severe human arrhythmia phenotypes (eg E1425G, V1516D, R1788W) were rare in the general population. Variants associated with less severe clinical and in vitro phenotypes were unexpectedly common. Studies with the ankyrin-B+/− mouse reveal both benefits of enhanced cardiac contractility, as well as costs in earlier senescence and reduced lifespan. Together these findings suggest a constellation of traits that we term “ankyrin-B syndrome”, which may contribute to both aging-related disorders and enhanced cardiac function.
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Affiliation(s)
- Peter J. Mohler
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- * To whom correspondence should be addressed. E-mail: (PM); (VB)
| | - Jane A. Healy
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Hui Xue
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Annibale A. Puca
- Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico MultiMedica, Milan, Italy
| | - Crystal F. Kline
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - R. Rand Allingham
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Evangelia G. Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Howard A. Rockman
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Vann Bennett
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, United States of America
- * To whom correspondence should be addressed. E-mail: (PM); (VB)
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Guo T, Ai X, Shannon TR, Pogwizd SM, Bers DM. Intra-sarcoplasmic reticulum free [Ca2+] and buffering in arrhythmogenic failing rabbit heart. Circ Res 2007; 101:802-10. [PMID: 17704210 DOI: 10.1161/circresaha.107.152140] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Smaller Ca2+ transients and systolic dysfunction in heart failure (HF) can be largely explained by reduced total sarcoplasmic reticulum (SR) Ca2+ content ([Ca]SRT). However, it is unknown whether low [Ca]SRT is manifest as reduced: (1) intra-SR free [Ca2+] ([Ca2+]SR), (2) intra-SR Ca2+ buffering, or (3) SR volume (as percentage of cell volume). Here we assess these possibilities in a well-characterized rabbit model of nonischemic HF. In HF versus control myocytes, diastolic [Ca2+]SR is similar at 0.1-Hz stimulation, but the increase in both [Ca2+]SR and [Ca]SRT as frequency increases to 1 Hz is blunted in HF. Direct measurement of intra-SR Ca2+ buffering (by simultaneous [Ca2+]SR and [Ca]SRT measurement) showed no change in HF. Diastolic [Ca]SRT changes paralleled [Ca2+]SR, suggesting that SR volume is not appreciably altered in HF. Thus, reduced [Ca]SRT in HF is associated with comparably reduced [Ca2+]SR. Fractional [Ca2+]SR depletion increased progressively with stimulation frequency in control but was blunted in HF (consistent with the blunted force-frequency relationship in HF). By studying a range of [Ca2+]SR, analysis showed that for a given [Ca]SR, fractional SR Ca2+ release was actually higher in HF. For both control and HF myocytes, SR Ca2+ release terminated when [Ca2+]SR dropped to 0.3 to 0.5 mmol/L during systole, consistent with a role for declining [Ca2+]SR in the dynamic shutoff of SR Ca2+ release. We conclude that low total SR Ca2+ content in HF, and reduced SR Ca2+ release, is attributable to reduced [Ca2+]SR, not to alterations in SR volume or Ca2+ buffering capacity.
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Affiliation(s)
- Tao Guo
- Department of Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
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Stypmann J, Engelen MA, Orwat S, Bilbilis K, Rothenburger M, Eckardt L, Haverkamp W, Horst J, Dworniczak B, Pennekamp P. Cardiovascular characterization of Pkd2+/LacZ mice, an animal model for the autosomal dominant polycystic kidney disease type 2 (ADPKD2). Int J Cardiol 2007; 120:158-66. [PMID: 17182135 DOI: 10.1016/j.ijcard.2006.09.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 08/27/2006] [Accepted: 09/20/2006] [Indexed: 01/15/2023]
Abstract
BACKGROUND Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in PKD1 or PKD2. Patients with ADPKD have an increased incidence of cardiac valve abnormalities and left ventricular hypertrophy. Systematic analyses of cardiovascular involvement have so far been performed only on genetically unclassified patients or on ADPKD1 patients, but not on genetically defined ADPKD2 patients. Even existing Pkd1 or Pkd2 mouse models were not thoroughly analyzed in this respect. Therefore, the aim of this project was the noninvasive functional cardiovascular characterization of a mouse model for ADPKD2. METHODS Pkd2(+/LacZ) mice and wildtype controls were classified into 8 groups with respect to gender, age and genotype. In addition, two subgroups of female mice were analyzed for cardiac function before and during advanced pregnancy. Doppler-echocardiographic as well as histological studies were performed. RESULTS Doppler-echocardiography did not reveal significant cardiovascular changes. Heart rate and left ventricular (LV) length, LV mass, LV enddiastolic and LV endsystolic diameters did not differ significantly among the various groups when comparing wildtype and knockout mice. There were no significant differences except for a tendency towards higher maximal early and late flow velocities over the mitral valve in old wildtype mice. CONCLUSIONS Non-invasive phenotyping using ultrasound did not reveal significant cardiovascular difference between adult Pkd2(+/LacZ) and WT mice. Due to the lack of an obvious renal phenotype in heterozygous mice, it is likely that in conventional ADPKD knock out mouse models severe cardiac problems appear too late to be identified during the reduced lifespan of the animals.
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Affiliation(s)
- Jörg Stypmann
- Department of Cardiology and Angiology, Hospital of the University of Münster, Germany
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Lauton-Santos S, Guatimosim S, Castro CH, Oliveira FA, Almeida AP, Dias-Peixoto MF, Gomes MA, Pessoa P, Pesquero JL, Pesquero JB, Bader M, Cruz JS. Kinin B1 receptor participates in the control of cardiac function in mice. Life Sci 2007; 81:814-22. [PMID: 17714737 DOI: 10.1016/j.lfs.2007.06.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2007] [Revised: 06/22/2007] [Accepted: 06/29/2007] [Indexed: 10/23/2022]
Abstract
The kinins have an important role in control of the cardiovascular system. They have been associated with protective effects in the heart tissue. Kinins act through stimulation of two 7-transmembrane G protein-coupled receptors, denoted B(1) and B(2) receptors. However, the physiological relevance of B(1) receptor in the heart has not been clearly established. Using B(1) kinin receptor gene knock-out mice we tested the hypothesis that the B(1) receptor plays an important role in the control of baseline cardiac function. We examined the functional aspects of the intact heart and also in the isolated cardiomyocytes to study intracellular Ca(2+) cycling by using confocal microscopy and whole-cell voltage clamp techniques. We measured heart rate, diastolic and systolic tension, contraction and relaxation rates and, coronary perfusion pressure. Whole-cell voltage clamp was performed to measure L-type Ca(2+) current (I(Ca,L)). The hearts from B(1)(-/-) mice showed smaller systolic tension. The average values for WT and B(1)(-/-) mice were 2.6+/-0.04 g vs. 1.6+/-0.08 g, respectively. This result can be explained, at least in part, by the decrease in the Ca(2+) transient (3.1+/-0.06 vs. 3.4+/-0.09 for B(1)(-/-) and WT, respectively). There was an increase in I(Ca,L) at depolarized membrane potentials. Interestingly, the inactivation kinetics of I(Ca,L) was statistically different between the groups. The coronary perfusion pressure was higher in the hearts from B(1)(-/-) mice indicating an increase in coronary resistance. This result can be explained by the significant reduction of eNOS (NOS-3) expression in the aorta of B(1)(-/-) mice. Collectively, our results demonstrate that B(1) receptor exerts a fundamental role in the mammalian cardiac function.
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Affiliation(s)
- Sandra Lauton-Santos
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Badea CT, Hedlund LW, Mackel JFB, Mao L, Rockman HA, Johnson GA. Cardiac Micro–Computed Tomography for Morphological and Functional Phenotyping of Muscle LIM Protein Null Mice. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The purpose of this study was to investigate the use of micro–computed tomography (micro-CT) for morphological and functional phenotyping of muscle LIM protein (MLP) null mice and to compare micro-CT with M-mode echocardiography. MLP null mice and controls were imaged using both micro-CT and M-mode echocardiography. For micro-CT, we used a custom-built scanner. Following a single intravenous injection of a blood pool contrast agent (Fenestra VC, ART Advanced Research Technologies, Saint-Laurent, QC) and using a cardiorespiratory gating, we acquired eight phases of the cardiac cycle (every 15 ms) and reconstructed three-dimensional data sets with 94-micron isotropic resolution. Wall thickness and volumetric measurements of the left ventricle were performed, and cardiac function was estimated. Micro-CT and M-mode echocardiography showed both morphological and functional aspects that separate MLP null mice from controls. End-diastolic and -systolic volumes were increased significantly three- and fivefold, respectively, in the MLP null mice versus controls. Ejection fraction was reduced by an average of 32% in MLP null mice. The data analysis shows that two imaging modalities provided different results partly owing to the difference in anesthesia regimens. Other sources of errors for micro-CT are also analyzed. Micro-CT can provide the four-dimensional data (three-dimensional isotropic volumes over time) required for morphological and functional phenotyping in mice.
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Affiliation(s)
- Cristian T. Badea
- From the Center for In Vivo Microscopy, Department of Radiology, and Department of Medicine, Duke University Medical Center, Durham, NC
| | - Laurence W. Hedlund
- From the Center for In Vivo Microscopy, Department of Radiology, and Department of Medicine, Duke University Medical Center, Durham, NC
| | - Julie F. Boslego Mackel
- From the Center for In Vivo Microscopy, Department of Radiology, and Department of Medicine, Duke University Medical Center, Durham, NC
| | - Lan Mao
- From the Center for In Vivo Microscopy, Department of Radiology, and Department of Medicine, Duke University Medical Center, Durham, NC
| | - Howard A. Rockman
- From the Center for In Vivo Microscopy, Department of Radiology, and Department of Medicine, Duke University Medical Center, Durham, NC
| | - G. Allan Johnson
- From the Center for In Vivo Microscopy, Department of Radiology, and Department of Medicine, Duke University Medical Center, Durham, NC
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Costandi PN, McCulloch AD, Omens JH, Frank LR. High-resolution longitudinal MRI of the transition to heart failure. Magn Reson Med 2007; 57:714-20. [PMID: 17390366 PMCID: PMC4482467 DOI: 10.1002/mrm.21182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The development of heart failure (HF) is an evolving process that entails both structural and functional changes through time. While the physiological state of cardiac pathologies has been well characterized, less is known about the transition from a normal to a maladaptive state. Magnetic resonance imaging (MRI) is a noninvasive technique that facilitates longitudinal experiments to follow the progression of cardiac structural and physiological disorders over time. Transgenic murine models of cardiac disease, such as the muscle LIM protein-deficient strain used in this study, offer populations of a reproducible phenotype that readily lend themselves to serial studies. In this longitudinal study, high spatial and temporal resolution time-course MR images revealed an abrupt and brief phase of major anatomical restructuring during which the ventricular chamber dilated and the wall thinned. The ability of MRI to acquire spatially and temporally resolved images enabled the 3D estimation of cavity volume and wall mass changes with time. It was concluded that, using an imaging protocol of high temporal resolution, MRI has the adequate spatial and temporal imaging resolution to allow for the detection and quantification of rapidly occurring transitional phases in a single mouse heart as it progresses toward failure.
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Affiliation(s)
- Peter N Costandi
- Department of Bioengineering, University of California-San Diego, La Jolla, California 92093-0613, USA.
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Hoshijima M, Knöll R, Pashmforoush M, Chien KR. Reversal of calcium cycling defects in advanced heart failure toward molecular therapy. J Am Coll Cardiol 2007; 48:A15-23. [PMID: 17084280 DOI: 10.1016/j.jacc.2006.06.070] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 05/22/2006] [Accepted: 06/22/2006] [Indexed: 02/04/2023]
Abstract
Heart failure is a growing major cause of human morbidity and mortality worldwide. A wave of new insights from diverse laboratories has begun to uncover new therapeutic strategies that affect the molecular pathways within cardiomyocytes that drive heart failure progression. Using an integrative approach that employs insights from genetic-based studies in mouse and humans and in vivo somatic gene transfer studies, we have uncovered a new link between stress signals mediated by mechanical stretch and defects in sarcoplasmic reticulum (SR) calcium cycling. An intrinsic mechanical stress sensing system is embedded in the Z disc of cardiomyocytes, and defects in stretch responses can lead to heart failure progression and associated increases in wall stress. Reversal of the chronic increases in wall stress by promoting SR calcium cycling can prevent and partially reverse heart failure progression in multiple genetic and acquired model systems of heart failure in both small and large animals. We propose that reversal of advanced heart failure is possible by targeting the defects in SR calcium cycling, which may be a final common pathway for the progression of many forms of heart failure.
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Affiliation(s)
- Masahiko Hoshijima
- Institute of Molecular Medicine, University of California San Diego, La Jolla, California, USA
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Reyes M, Steinhelper ME, Alvarez JA, Escobedo D, Pearce J, Valvano JW, Pollock BH, Wei CL, Kottam A, Altman D, Bailey S, Thomsen S, Lee S, Colston JT, Oh JH, Freeman GL, Feldman MD. Impact of physiological variables and genetic background on myocardial frequency-resistivity relations in the intact beating murine heart. Am J Physiol Heart Circ Physiol 2006; 291:H1659-69. [PMID: 16699072 DOI: 10.1152/ajpheart.00609.2005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Conductance measurements for generation of an instantaneous left ventricular (LV) volume signal in the mouse are limited, because the volume signal is a combination of blood and LV muscle, and only the blood signal is desired. We have developed a conductance system that operates at two simultaneous frequencies to identify and remove the myocardial contribution to the instantaneous volume signal. This system is based on the observation that myocardial resistivity varies with frequency, whereas blood resistivity does not. For calculation of LV blood volume with the dual-frequency conductance system in mice, in vivo murine myocardial resistivity was measured and combined with an analytic approach. The goals of the present study were to identify and minimize the sources of error in the measurement of myocardial resistivity to enhance the accuracy of the dual-frequency conductance system. We extended these findings to a gene-altered mouse model to determine the impact of measured myocardial resistivity on the calculation of LV pressure-volume relations. We examined the impact of temperature, timing of the measurement during the cardiac cycle, breeding strain, anisotropy, and intrameasurement and interanimal variability on the measurement of intact murine myocardial resistivity. Applying this knowledge to diabetic and nondiabetic 11- and 20- to 24-wk-old mice, we demonstrated differences in myocardial resistivity at low frequencies, enhancement of LV systolic function at 11 wk and LV dilation at 20–24 wk, and histological and electron-microscopic studies demonstrating greater glycogen deposition in the diabetic mice. This study demonstrated the accurate technique of measuring myocardial resistivity and its impact on the determination of LV pressure-volume relations in gene-altered mice.
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Affiliation(s)
- Maricela Reyes
- Univ. of Texas Health Science Center, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA
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Lorenzen-Schmidt I, Stuyvers BD, ter Keurs HE, Date MO, Hoshijima M, Chien KR, McCulloch AD, Omens JH. Young MLP deficient mice show diastolic dysfunction before the onset of dilated cardiomyopathy. J Mol Cell Cardiol 2006; 39:241-50. [PMID: 15978612 PMCID: PMC4484861 DOI: 10.1016/j.yjmcc.2005.05.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 04/29/2005] [Accepted: 05/11/2005] [Indexed: 11/30/2022]
Abstract
Targeted deletion of cytoskeletal muscle LIM protein (MLP) in mice consistently leads to dilated cardiomyopathy (DCM) after one or more months. However, next to nothing is known at present about the mechanisms of this process. We investigated whether diastolic performance including passive mechanics and systolic behavior are altered in 2-week-old MLP knockout (MLPKO) mice, in which heart size, fractional shortening and ejection fraction are still normal. Right ventricular trabeculae were isolated from 2-week-old MLPKO and wildtype mice and placed in an apparatus that allowed force measurements and sarcomere length measurements using laser diffraction. During a twitch from the unloaded state at 1 Hz, MLPKO muscles relengthened to slack length more slowly than controls, although the corresponding force relaxation time was unchanged. Active developed stress at a diastolic sarcomere length of 2.00 microm was preserved in MLPKO trabeculae over a wide range of pacing frequencies. Force relaxation under the same conditions was consistently prolonged compared with wildtype controls, whereas time to peak and maximum rate of force generation were not significantly altered. Ca2+ content of the sarcoplasmic reticulum (SR) and the quantities of Ca2+ handling proteins were similar in both genotypes. In summary, young MLPKO mice revealed substantial alterations in passive myocardial properties and relaxation time, but not in most systolic characteristics. These results indicate that the progression to heart failure in the MLPKO model may be driven by diastolic myocardial dysfunction and abnormal passive properties rather than systolic dysfunction.
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Affiliation(s)
- Ilka Lorenzen-Schmidt
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093-0412, USA
| | - Bruno D. Stuyvers
- Department of Biophysics and Physiology, University of Calgary, Calgary, Alta., Canada T2N 1N4
| | - Henk E.D.J. ter Keurs
- Department of Biophysics and Physiology, University of Calgary, Calgary, Alta., Canada T2N 1N4
| | - Moto-o Date
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613, USA
| | - Masahiko Hoshijima
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613, USA
| | - Kenneth R. Chien
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613, USA
| | - Andrew D. McCulloch
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093-0412, USA
| | - Jeffrey H. Omens
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093-0412, USA
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613, USA
- Corresponding author. Tel.: +1 858 534 8102; fax: +1 858 534 0522.
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Gurley SB, Allred A, Le TH, Griffiths R, Mao L, Philip N, Haystead TA, Donoghue M, Breitbart RE, Acton SL, Rockman HA, Coffman TM. Altered blood pressure responses and normal cardiac phenotype in ACE2-null mice. J Clin Invest 2006; 116:2218-25. [PMID: 16878172 PMCID: PMC1518789 DOI: 10.1172/jci16980] [Citation(s) in RCA: 259] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2002] [Accepted: 06/06/2006] [Indexed: 12/27/2022] Open
Abstract
The carboxypeptidase ACE2 is a homologue of angiotensin-converting enzyme (ACE). To clarify the physiological roles of ACE2, we generated mice with targeted disruption of the Ace2 gene. ACE2-deficient mice were viable, fertile, and lacked any gross structural abnormalities. We found normal cardiac dimensions and function in ACE2-deficient animals with mixed or inbred genetic backgrounds. On the C57BL/6 background, ACE2 deficiency was associated with a modest increase in blood pressure, whereas the absence of ACE2 had no effect on baseline blood pressures in 129/SvEv mice. After acute Ang II infusion, plasma concentrations of Ang II increased almost 3-fold higher in ACE2-deficient mice than in controls. In a model of Ang II-dependent hypertension, blood pressures were substantially higher in the ACE2-deficient mice than in WT. Severe hypertension in ACE2-deficient mice was associated with exaggerated accumulation of Ang II in the kidney, as determined by MALDI-TOF mass spectrometry. Although the absence of functional ACE2 causes enhanced susceptibility to Ang II-induced hypertension, we found no evidence for a role of ACE2 in the regulation of cardiac structure or function. Our data suggest that ACE2 is a functional component of the renin-angiotensin system, metabolizing Ang II and thereby contributing to regulation of blood pressure.
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Affiliation(s)
- Susan B. Gurley
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Alicia Allred
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Thu H. Le
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Robert Griffiths
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Lan Mao
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Nisha Philip
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Timothy A. Haystead
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Mary Donoghue
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Roger E. Breitbart
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Susan L. Acton
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Howard A. Rockman
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
| | - Thomas M. Coffman
- Division of Nephrology and
Division of Cardiology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA.
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA.
Department of Cardiovascular Biology, Millennium Pharmaceuticals Inc., Cambridge, Massachusetts, USA
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Costandi PN, Frank LR, McCulloch AD, Omens JH. Role of diastolic properties in the transition to failure in a mouse model of the cardiac dilatation. Am J Physiol Heart Circ Physiol 2006; 291:H2971-9. [PMID: 16861693 PMCID: PMC3334322 DOI: 10.1152/ajpheart.00571.2006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although the physiological states of hypertrophic remodeling and congestive heart failure have been intensively studied, less is known about the transition from one to the other. The use of genetically engineered murine models of heart failure has proven valuable in characterizing the progression of remodeling and its ultimate decompensation to failure. Mice deficient in the cytoskeletal muscle LIM-only protein (MLP) are known to present with a clinical picture of dilated cardiomyopathy and transition to failure as adults. Longitudinal high-field magnetic resonance (MR) cardiac imaging provided a time course of remodeling where an improvement in ejection fraction and stroke volume (15- vs. 31-wk MLP(-/-) mice; P < 0.0001) was temporally concurrent with an abrupt phase of end-diastolic chamber dilatation. Hemodynamic analysis conducted throughout that dilatation phase showed improved ratio of maximum first derivative of pressure to end-diastolic pressure (dP/dt(max)/EDP; 15- vs. 31-wk MLP(-/-) mice; P < 0.0005), ratio of minimum first derivative of pressure to EDP (dP/dt(min)/EDP; 15- vs. 31-wk MLP(-/-) mice; P < 0.003), and developed pressure (15- vs. 31-wk MLP(-/-) mice; P < 0.0001) levels in the MLP(-/-) mice. Computational modeling techniques were used to estimate the EDP volume relationship, revealing that although MLP hearts possess a stiffer stress-strain relation, chamber compliance increased as a function of dilatation. This detailed physiological characterization during a phase of rapid anatomical remodeling suggests that systolic function in the MLP(-/-) mice may temporarily improve as a result of alterations in chamber compliance, which are mediated by dilatation. In turn, a balance may exist between exploiting the Frank-Starling mechanism and altering chamber compliance that maintains function in the absence of hypertrophic growth. Though initially compensatory, this process may exhaust itself and consequently transition to a maladaptive course.
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Affiliation(s)
- Peter N Costandi
- Dept. of Bioengineering, University of California, San Diego, La Jolla, CA 92093-0613, USA.
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Wilding JR, Joubert F, de Araujo C, Fortin D, Novotova M, Veksler V, Ventura-Clapier R. Altered energy transfer from mitochondria to sarcoplasmic reticulum after cytoarchitectural perturbations in mice hearts. J Physiol 2006; 575:191-200. [PMID: 16740607 PMCID: PMC1819422 DOI: 10.1113/jphysiol.2006.114116] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Sarcoplasmic reticulum (SR) calcium pump function requires a high local ATP/ADP ratio, which can be maintained by direct nucleotide channelling from mitochondria, and by SR-bound creatine kinase (CK)-catalysed phosphate-transfer from phosphocreatine. We hypothesized that SR calcium uptake supported by mitochondrial direct nucleotide channelling, but not bound CK, depends on the juxtaposition of these organelles. To test this, we studied a well-described model of cytoarchitectural disorganization, the muscle LIM protein (MLP)-null mouse heart. Subcellular organization was characterized using electron microscopy, and mitochondrial, SR and myofibrillar function were assessed in saponin-permeabilized fibres by measuring respiration rates and caffeine-induced tension transients. MLP-null hearts had fewer, less-tightly packed intermyofibrillar mitochondria, and more subsarcolemmal mitochondria. The apparent mitochondrial Km for ADP was significantly lower in the MLP-null heart than in control (175 +/- 15 and 270 +/- 33 microM, respectively), indicating greater ADP accessibility, although maximal respiration rate, mitochondrial content and total CK activity were unaltered. Active tension in the myofibres of MLP-null mice was 54% lower than in controls (39 +/- 3 and 18 +/- 1 mN mm(-2), respectively), consistent with cytoarchitectural disorganization. SR calcium loading in the myofibres of MLP-null mice was similar to that in control myofibres when energy support was provided via Bound CK, but approximately 36% lower than controls when energy support was provided by mitochondrial (P < 0.05). Mitochondrial support for SR calcium uptake was also specifically decreased in the desmin-null heart, which is another model of cytoarchitectural perturbation. Thus, despite normal oxidative capacity, direct nucleotide channelling to the SR was impaired in MLP deficiency, concomitant with looser mitochondrial packing and increased nucleotide accessibility to this organelle. Changes in cytoarchitecture may therefore impair subcellular energy transfer and contribute to energetic and contractile dysfunction.
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