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Deng J, Guo Y, Zhang G, Zhang L, Kem D, Yu X, Jiang H, Li H. M 2 muscarinic autoantibodies and thyroid hormone promote susceptibility to atrial fibrillation and sinus tachycardia in an autoimmune rabbit model. Exp Physiol 2021; 106:882-890. [PMID: 33550676 DOI: 10.1113/ep089284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 02/04/2021] [Indexed: 02/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? Do autoantibodies to the M2 muscarinic receptor (M2R-AAbs) have the potential to facilitate specific sustained tachyarrhythmias in the presence of thyroxine (T4 ) in rabbits? What is the main finding and its importance? The M2R-AAb and T4 jointly destabilized the electrophysiological properties, thus promoting the occurrence of atrial and sinus tachyarrhythmias in rabbits. These findings provide a practical basis for understanding the pathophysiological role of M2R-AAb alone and with T4 in arrhythmia induction and might provide an innovative option for treatment of Graves' disease with rhythm disturbance. ABSTRACT Activating autoantibodies toward the β1/2 -adrenergic receptors (β1/2AR-AAbs) and M2 muscarinic receptor (M2R-AAbs) are present in a high proportion of patients with Graves' disease. We previously demonstrated that β1/2AR-AAbs with or without the presence of M2R-AAbs in combination with excessive thyroxine (T4 ) increased the induction of sustained tachyarrhythmias in an autoimmune rabbit model. However, the separate role of M2R-AAbs and their interaction with T4 are not clear. The aim of this study was to investigate the impact of M2R-AAbs and T4 on the induction of cardiac arrhythmias in a similar rabbit model. Ten New Zealand White rabbits were randomly divided into two groups. In group A (n = 6), the rabbits were immunized with the second extracellular loop peptide of M2R and subjected to 2 weeks of T4 treatment. In group B (n = 4), the rabbits were treated only with T4 for 2 weeks. After induction of general anaesthesia, rabbits were subjected to an electrophysiological study at 0 (pre-immune), 6 (post-immune) and 8 weeks (post-immune+T4 treatment) in group A and at 0 (baseline) and 8 weeks (T4 treatment) in group B. Each rabbit served as its own control. In group A, high levels and activity of M2R-AAbs were detected in all immunized animals. Thyroxine in combination with immunization significantly increased induction of sustained sinus tachycardia and atrial fibrillation in comparison to the pre-immune state. In group B, T4 predominantly induced sustained sinus tachycardia. This study demonstrated that M2R-AAbs and T4 jointly increased the susceptibility to both sinus and atrial tachyarrhythmias. The data supported the pathophysiological role of M2R-AAbs in hyperthyroidism-associated supraventricular tachyarrhythmias.
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Affiliation(s)
- Jielin Deng
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
- Department of Medicine, Endocrinology Section and the Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Yankai Guo
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Gege Zhang
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Ling Zhang
- Cardiac Pacing and Electrophysiology Department, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - David Kem
- Department of Medicine, Endocrinology Section and the Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Xichun Yu
- Department of Medicine, Endocrinology Section and the Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Hong Jiang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
- Cardiovascular Research Institute, Wuhan University, Wuhan, 430060, China
- Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Hongliang Li
- Department of Medicine, Endocrinology Section and the Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
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Yoshizawa A, Nagai S, Baba Y, Yamada T, Matsui M, Tanaka H, Miyoshi SI, Amagai M, Yoshikawa T, Fukuda K, Ogawa S, Koyasu S. Autoimmunity against M2muscarinic acetylcholine receptor induces myocarditis and leads to a dilated cardiomyopathy-like phenotype. Eur J Immunol 2012; 42:1152-63. [DOI: 10.1002/eji.201142104] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Akihiro Yoshizawa
- Department of Microbiology and Immunology, Keio University School of Medicine; Tokyo Japan
- Department of Cardiology; Keio University School of Medicine; Tokyo Japan
- Tokyo Dental College Ichikawa Hospital; Ichikawa Japan
| | - Shigenori Nagai
- Department of Microbiology and Immunology, Keio University School of Medicine; Tokyo Japan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency; Tokyo Japan
| | - Yukiko Baba
- Department of Microbiology and Immunology, Keio University School of Medicine; Tokyo Japan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency; Tokyo Japan
| | - Taketo Yamada
- Department of Pathology; Keio University School of Medicine; Tokyo Japan
| | - Minoru Matsui
- Department of Pharmacy; Chiba Institute of Science; Chiba Japan
| | - Hikaru Tanaka
- Department of Pharmacology; Toho University Faculty of Pharmaceutical Sciences; Chiba Japan
| | | | - Masayuki Amagai
- Department of Dermatology; Keio University School of Medicine; Tokyo Japan
| | - Tsutomu Yoshikawa
- Department of Cardiology; Keio University School of Medicine; Tokyo Japan
| | - Keiichi Fukuda
- Department of Cardiology; Keio University School of Medicine; Tokyo Japan
| | - Satoshi Ogawa
- Department of Cardiology; Keio University School of Medicine; Tokyo Japan
| | - Shigeo Koyasu
- Department of Microbiology and Immunology, Keio University School of Medicine; Tokyo Japan
- Research Center for Science Systems, Japan Society for the Promotion of Science; Tokyo Japan
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Brette F, Leroy J, Le Guennec JY, Sallé L. Ca2+ currents in cardiac myocytes: Old story, new insights. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2005; 91:1-82. [PMID: 16503439 DOI: 10.1016/j.pbiomolbio.2005.01.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Calcium is a ubiquitous second messenger which plays key roles in numerous physiological functions. In cardiac myocytes, Ca2+ crosses the plasma membrane via specialized voltage-gated Ca2+ channels which have two main functions: (i) carrying depolarizing current by allowing positively charged Ca2+ ions to move into the cell; (ii) triggering Ca2+ release from the sarcoplasmic reticulum. Recently, it has been suggested than Ca2+ channels also participate in excitation-transcription coupling. The purpose of this review is to discuss the physiological roles of Ca2+ currents in cardiac myocytes. Next, we describe local regulation of Ca2+ channels by cyclic nucleotides. We also provide an overview of recent studies investigating the structure-function relationship of Ca2+ channels in cardiac myocytes using heterologous system expression and transgenic mice, with descriptions of the recently discovered Ca2+ channels alpha(1D) and alpha(1E). We finally discuss the potential involvement of Ca2+ currents in cardiac pathologies, such as diseases with autoimmune components, and cardiac remodeling.
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Affiliation(s)
- Fabien Brette
- School of Biomedical Sciences, University of Leeds, Worsley Building Leeds, LS2 9NQ, UK.
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Lomize AL, Pogozheva ID, Mosberg HI. Structural organization of G-protein-coupled receptors. J Comput Aided Mol Des 1999; 13:325-53. [PMID: 10425600 DOI: 10.1023/a:1008050821744] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Atomic-resolution structures of the transmembrane 7-alpha-helical domains of 26 G-protein-coupled receptors (GPCRs) (including opsins, cationic amine, melatonin, purine, chemokine, opioid, and glycoprotein hormone receptors and two related proteins, retinochrome and Duffy erythrocyte antigen) were calculated by distance geometry using interhelical hydrogen bonds formed by various proteins from the family and collectively applied as distance constraints, as described previously [Pogozheva et al., Biophys. J., 70 (1997) 1963]. The main structural features of the calculated GPCR models are described and illustrated by examples. Some of the features reflect physical interactions that are responsible for the structural stability of the transmembrane alpha-bundle: the formation of extensive networks of interhelical H-bonds and sulfur-aromatic clusters that are spatially organized as 'polarity gradients'; the close packing of side-chains throughout the transmembrane domain; and the formation of interhelical disulfide bonds in some receptors and a plausible Zn2+ binding center in retinochrome. Other features of the models are related to biological function and evolution of GPCRs: the formation of a common 'minicore' of 43 evolutionarily conserved residues; a multitude of correlated replacements throughout the transmembrane domain; an Na(+)-binding site in some receptors, and excellent complementarity of receptor binding pockets to many structurally dissimilar, conformationally constrained ligands, such as retinal, cyclic opioid peptides, and cationic amine ligands. The calculated models are in good agreement with numerous experimental data.
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Affiliation(s)
- A L Lomize
- College of Pharmacy, University of Michigan, Ann Arbor 48109-1065, USA
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Liu HR, Zhao RR, Zhi JM, Wu BW, Fu ML. Screening of serum autoantibodies to cardiac beta1-adrenoceptors and M2-muscarinic acetylcholine receptors in 408 healthy subjects of varying ages. Autoimmunity 1999; 29:43-51. [PMID: 10052684 DOI: 10.3109/08916939908995971] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Autoantibodies to cardiac beta1-adrenoceptors and M2-muscarinic receptors have mainly been found in the sera of patients with idiopathic dilated cardiomyopathy (DCM). In order to elucidate the pathological significance of these autoantibodies in DCM, it is necessary to understand their characteristic distribution in a healthy population of different genders and ages. The peptides corresponding to the sequences of the second extracellular loops of the human beta1-adrenoceptor and M2-muscarinic receptors were therefore used as antigens to screen the sera of 408 healthy subjects of different ages (ranging from 0.5 to 85 years). Of 408 sera, 41 (10.0%) and 46 (11.3%) recognized the beta1-adrenoceptor and M2-muscarinic receptor peptides respectively. Of the positive sera for beta1-adrenoceptors and M2-muscarinic receptors, up to 63.4% and 56.5% had both anti-beta1-adrenoceptor and anti-M2-muscarinic receptor autoantibodies respectively. The antibody titres of the positive sera of healthy subjects were all of a low level, with a geometric mean titre of 1:42+/-1.9 for anti-beta1-adrenoceptor antibodies and 1:51+/-1.7 for anti-M2-muscarinic receptor antibodies. The frequency of occurrence of autoantibodies to both receptors in the sera of healthy subjects increased significantly with age. In conclusion, the autoantibodies to beta1-adrenoceptors and M2-muscarinic receptors in the sera of healthy subjects are characterized by a low frequency of occurrence and low titre, with the frequency of occurrence increasing with age.
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Affiliation(s)
- H R Liu
- Laboratory of Cardiovascular Physiology, Shanxi Medical University, Taiyuan, China
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Fu ML. Characterization of anti-heart M2 muscarinic receptor antibodies--a combined clinical and experimental study. Mol Cell Biochem 1996; 163-164:343-7. [PMID: 8974074 DOI: 10.1007/bf00408675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To elucidate the relationship between autoimmunity and idiopathic dilated cardiomyopathy has been one of today's heated topics in the field of heart research. So far it has been identified that there are a variety of autoantibodies including antireceptor autoantibodies. However, the role of these autoantibodies in the development of dilated cardiomyopathy has not been defined. An increasing number of in vitro studies showed that these autoantibodies had different functions, suggesting that they may play different roles in the pathogenesis of cardiomyopathy. The main purpose of this article is to briefly go through the results obtained from both clinical and experimental in vitro studies on anti-M2 muscarinic receptor antibodies to see where we stand in the understanding of the role of these autoantibodies in the pathogenesis of idiopathic dilated cardiomyopathy.
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Affiliation(s)
- M L Fu
- Wallenberg Laboratory, Sahlgren's Hospital, University of Göteborg, Sweden
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