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Mirna M, Paar V, Kraus T, Sotlar K, Wernly B, Pistulli R, Hoppe UC, Lichtenauer M. Autoimmune myocarditis is not associated with left ventricular systolic dysfunction. Eur J Clin Invest 2019; 49:e13132. [PMID: 31125424 PMCID: PMC6771695 DOI: 10.1111/eci.13132] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/26/2019] [Accepted: 05/21/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Experimental autoimmune myocarditis (EAM) is a common animal model for the investigation of the pathophysiology of myocarditis. Because of diverging findings from previous studies, we performed serial echocardiographic examinations throughout the course of the disease and investigated the dimensions of the murine heart and left ventricular (LV) systolic function. MATERIALS AND METHODS Experimental autoimmune myocarditis was induced in male Balb/c mice by subcutaneous injection of a fragment of the α-myosin heavy chain (MyHC-α 614-629: Ac-SLKLMATLFSTYASAD). Transthoracic echocardiography was performed on days 0, 7 and 21 in healthy animals and mice with EAM. RESULTS Experimental autoimmune myocarditis was associated with a reduction in LV systolic function and an increase in LV internal diameter in diastole (LVIDd) and systole (LVIDs) 7 days postimmunization. After 21 days, EAM led to a significant increase in LV-thickness (1.3-fold increase in LV anterior wall diameter in diastole [LVAWDd]), but there was no difference in LV systolic function between immunized animals and healthy controls. LV-thickness correlated well with the severity of myocarditis in the histopathological examination (LVAWDd: rs = 0.603, P = 0.003, LV anterior wall diameter in systole (LVAWDs): rs = 0.718, P < 0.0001). CONCLUSION Our results indicate that EAM leads to an initial dilatation of the LV that is followed by ventricular "hypertrophy." On day 21, there was no significant difference in LV systolic function between immunized animals and controls. Furthermore, the ageing of the animals had a major impact on the echocardiographic parameters; therefore, the use of healthy age-matched controls seems warranted when echocardiography is performed in rodents.
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Affiliation(s)
- Moritz Mirna
- Department of Cardiology, Clinic of Internal Medicine II, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Vera Paar
- Department of Cardiology, Clinic of Internal Medicine II, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Theo Kraus
- Institute of Pathology, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Karl Sotlar
- Institute of Pathology, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Bernhard Wernly
- Department of Cardiology, Clinic of Internal Medicine II, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Rudin Pistulli
- Department of Cardiology I, Coronary and Peripheral Vascular Diseases, Heart Failure, University Hospital Münster, Münster, Germany
| | - Uta C Hoppe
- Department of Cardiology, Clinic of Internal Medicine II, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | - Michael Lichtenauer
- Department of Cardiology, Clinic of Internal Medicine II, Paracelsus Medical University of Salzburg, Salzburg, Austria
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Krishnan B, Massilamany C, Basavalingappa RH, Gangaplara A, Rajasekaran RA, Afzal MZ, Khalilzad-Sharghi V, Zhou Y, Riethoven JJ, Nandi SS, Mishra PK, Sobel RA, Strande JL, Steffen D, Reddy J. Epitope Mapping of SERCA2a Identifies an Antigenic Determinant That Induces Mainly Atrial Myocarditis in A/J Mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 200:523-537. [PMID: 29229678 PMCID: PMC5760440 DOI: 10.4049/jimmunol.1701090] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/05/2017] [Indexed: 12/20/2022]
Abstract
Sarcoplasmic/endoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA)2a, a critical regulator of calcium homeostasis, is known to be decreased in heart failure. Patients with myocarditis or dilated cardiomyopathy develop autoantibodies to SERCA2a suggesting that they may have pathogenetic significance. In this report, we describe epitope mapping analysis of SERCA2a in A/J mice that leads us to make five observations: 1) SERCA2a contains multiple T cell epitopes that induce varying degrees of myocarditis. One epitope, SERCA2a 971-990, induces widespread atrial inflammation without affecting noncardiac tissues; the cardiac abnormalities could be noninvasively captured by echocardiography, electrocardiography, and magnetic resonance microscopy imaging. 2) SERCA2a 971-990-induced disease was associated with the induction of CD4 T cell responses and the epitope preferentially binds MHC class II/IAk rather than IEk By creating IAk/and IEk/SERCA2a 971-990 dextramers, the T cell responses were determined by flow cytometry to be Ag specific. 3) SERCA2a 971-990-sensitized T cells produce both Th1 and Th17 cytokines. 4) Animals immunized with SERCA2a 971-990 showed Ag-specific Abs with enhanced production of IgG2a and IgG2b isotypes, suggesting that SERCA2a 971-990 can potentially act as a common epitope for both T cells and B cells. 5) Finally, SERCA2a 971-990-sensitized T cells were able to transfer disease to naive recipients. Together, these data indicate that SERCA2a is a critical autoantigen in the mediation of atrial inflammation in mice and that our model may be helpful to study the inflammatory events that underlie the development of conditions such as atrial fibrillation in humans.
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Affiliation(s)
- Bharathi Krishnan
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583
| | - Chandirasegaran Massilamany
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583
- Vaccine Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892
| | - Rakesh H Basavalingappa
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583
| | - Arunakumar Gangaplara
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Rajkumar A Rajasekaran
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583
| | | | - Vahid Khalilzad-Sharghi
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583
| | - You Zhou
- Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68588
| | | | - Shyam S Nandi
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198; and
| | - Paras K Mishra
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198; and
| | - Raymond A Sobel
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94304
| | | | - David Steffen
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583
| | - Jay Reddy
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583;
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Basavalingappa RH, Massilamany C, Krishnan B, Gangaplara A, Kang G, Khalilzad-Sharghi V, Han Z, Othman S, Li Q, Riethoven JJ, Sobel RA, Steffen D, Reddy J. Identification of an Epitope from Adenine Nucleotide Translocator 1 That Induces Inflammation in Heart in A/J Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 186:3160-3175. [PMID: 27876151 DOI: 10.1016/j.ajpath.2016.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 06/27/2016] [Accepted: 08/03/2016] [Indexed: 01/21/2023]
Abstract
Heart failure, a leading cause of death in humans, can emanate from myocarditis. Although most individuals with myocarditis recover spontaneously, some develop chronic dilated cardiomyopathy. Myocarditis may result from both infectious and noninfectious causes, including autoimmune responses to cardiac antigens. In support of this notion, intracellular cardiac antigens, like cardiac myosin heavy chain-α, cardiac troponin-I, and adenine nucleotide translocator 1 (ANT1), have been identified as autoantigens in cardiac autoimmunity. Herein, we demonstrate that ANT1 can induce autoimmune myocarditis in A/J mice by generating autoreactive T cells. We show that ANT1 encompasses multiple immunodominant epitopes (namely, ANT1 21-40, ANT1 31-50, ANT1 171-190, and ANT1 181-200). Although all four peptides induce comparable T-cell responses, only ANT1 21-40 was found to be a major myocarditogenic epitope in immunized animals. The myocarditis-inducing ability of ANT1 21-40 was associated with the generation of T cells producing predominantly IL-17A, and the antigen-sensitized T cells could transfer the disease to naïve recipients. These data indicate that cardiac mitochondrial proteins can be target autoantigens in myocarditis, supporting the notion that the antigens released as a result of primary damage may contribute to the persistence of chronic inflammation through autoimmunity.
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Affiliation(s)
- Rakesh H Basavalingappa
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | | | - Bharathi Krishnan
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Arunakumar Gangaplara
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Guobin Kang
- Nebraska Center for Virology and School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Vahid Khalilzad-Sharghi
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Zhongji Han
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Shadi Othman
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Qingsheng Li
- Nebraska Center for Virology and School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | | | - Raymond A Sobel
- Department of Pathology, Stanford University School of Medicine, Stanford, California
| | - David Steffen
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Jay Reddy
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska.
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Massilamany C, Gangaplara A, Basavalingappa RH, Rajasekaran RA, Khalilzad-Sharghi V, Han Z, Othman S, Steffen D, Reddy J. Localization of CD8 T cell epitope within cardiac myosin heavy chain-α334-352 that induces autoimmune myocarditis in A/J mice. Int J Cardiol 2015; 202:311-21. [PMID: 26422020 DOI: 10.1016/j.ijcard.2015.09.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/02/2015] [Accepted: 09/15/2015] [Indexed: 12/25/2022]
Abstract
BACKGROUND Cardiac myosin heavy chain-α (Myhc), an intracellular protein expressed in the cardiomyocytes, has been identified as a major autoantigen in cardiac autoimmunity. In our studies with Myhc334-352-induced experimental autoimmune myocarditis in A/J mice (H-2a), we discovered that Myhc334-352, supposedly a CD4 T cell epitope, also induced antigen-specific CD8 T cells that transfer disease to naive animals. METHODS AND RESULTS In our efforts to identify the CD8 T cell determinants, we localized Myhc338-348 within the full length-Myhc334-352, leading to four key findings. (1) By acting as a dual epitope, Myhc338-348 induces both CD4 and CD8 T cell responses. (2) In a major histocompatibility complex (MHC) class I-stabilization assay, Myhc338-348 was found to bind H-2Dd-but not H-2Kk or H-2Ld-alleles. (3) The CD8 T cell response induced by Myhc338-348 was antigen-specific, as evaluated by MHC class I/H-2Dd dextramer staining. The antigen-sensitized T cells predominantly produced interferon-γ, the critical cytokine of effector cytotoxic T lymphocytes. (4) Myhc338-348 was found to induce myocarditis in immunized animals as determined by histology and magnetic resonance microscopy imaging. CONCLUSIONS Our data provide new insights as to how different immune cells can recognize the same antigen and inflict damage through different mechanisms.
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Affiliation(s)
- Chandirasegaran Massilamany
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Arunakumar Gangaplara
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Rakesh H Basavalingappa
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Rajkumar A Rajasekaran
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Vahid Khalilzad-Sharghi
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Zhongji Han
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Shadi Othman
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - David Steffen
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
| | - Jay Reddy
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, United States.
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Massilamany C, Gangaplara A, Jia T, Elowsky C, Li Q, Zhou Y, Reddy J. In situ detection of autoreactive CD4 T cells in brain and heart using major histocompatibility complex class II dextramers. J Vis Exp 2014:e51679. [PMID: 25145797 PMCID: PMC4389722 DOI: 10.3791/51679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
This report demonstrates the use of major histocompatibility complex (MHC) class II dextramers for detection of autoreactive CD4 T cells in situ in myelin proteolipid protein (PLP) 139-151-induced experimental autoimmune encephalomyelitis (EAE) in SJL mice and cardiac myosin heavy chain-α (Myhc) 334-352-induced experimental autoimmune myocarditis (EAM) in A/J mice. Two sets of cocktails of dextramer reagents were used, where dextramers(+) cells were analyzed by laser scanning confocal microscope (LSCM): EAE, IA(s)/PLP 139-151 dextramers (specific)/anti-CD4 and IA(s)/Theiler's murine encephalomyelitis virus (TMEV) 70-86 dextramers (control)/anti-CD4; and EAM, IA(k)/Myhc 334-352 dextramers/anti-CD4 and IA(k)/bovine ribonuclease (RNase) 43-56 dextramers (control)/anti-CD4. LSCM analysis of brain sections obtained from EAE mice showed the presence of cells positive for CD4 and PLP 139-151 dextramers, but not TMEV 70-86 dextramers suggesting that the staining obtained with PLP 139-151 dextramers was specific. Likewise, heart sections prepared from EAM mice also revealed the presence of Myhc 334-352, but not RNase 43-56-dextramer(+) cells as expected. Further, a comprehensive method has also been devised to quantitatively analyze the frequencies of antigen-specific CD4 T cells in the 'Z' serial images.
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Affiliation(s)
| | - Arunakumar Gangaplara
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln
| | - Ting Jia
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln
| | | | - Qingsheng Li
- Nebraska Center for Virology and School of Biological Sciences, University of Nebraska, Lincoln
| | - You Zhou
- Center for Biotechnology, University of Nebraska, Lincoln
| | - Jay Reddy
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln;
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