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Cunha DM, Tzirulnik PC, Costa PCDS, Cunha DM, Cunha ABD. Association of Anti-β1 and Anti-M2 Antibodies with Autonomic Nervous System Modulation in Patients with Chronic Chagas Cardiomyopathy. INTERNATIONAL JOURNAL OF CARDIOVASCULAR SCIENCES 2022. [DOI: 10.36660/ijcs.20200182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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2
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Skiba MA, Kruse AC. Autoantibodies as Endogenous Modulators of GPCR Signaling. Trends Pharmacol Sci 2020; 42:135-150. [PMID: 33358695 DOI: 10.1016/j.tips.2020.11.013] [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: 08/17/2020] [Revised: 11/24/2020] [Accepted: 11/28/2020] [Indexed: 02/06/2023]
Abstract
Endogenous self-reactive autoantibodies (AAs) recognize a range of G-protein-coupled receptors (GPCRs). They are frequently associated with cardiovascular, neurological, and autoimmune disorders, and in some cases directly impact disease progression. Many GPCR AAs modulate receptor signaling, but molecular details of their modulatory activity are not well understood. Technological advances have provided insight into GPCR biology, which now facilitates deeper understanding of GPCR AA function at the molecular level. Most GPCR AAs are allosteric modulators and exhibit a broad range of pharmacological properties, altering both receptor signaling and trafficking. Understanding GPCR AAs is not only important for defining how these unusual GPCR modulators function in disease, but also provides insight into the potential use and limitations of using therapeutic antibodies to modulate GPCR signaling.
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Affiliation(s)
- Meredith A Skiba
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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3
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Abstract
PURPOSE OF REVIEW The role of autoantibodies in arrhythmogenesis has been the subject of research in recent times. This review focuses on the rapidly expanding field of autoantibody-mediated cardiac arrhythmias. RECENT FINDINGS Since the discovery of cardiac autoantibodies more than three decades ago, a great deal of effort has been devoted to understanding their contribution to arrhythmias. Different cardiac receptors and ion channels were identified as targets for autoantibodies, the binding of which either initiates a signaling cascade or serves as a biomarker of underlying remodeling process. Consequently, the wide spectrum of heart rhythm disturbances may emerge, ranging from atrial to ventricular arrhythmias as well as conduction diseases, irrespective of concomitant structural heart disease or manifest autoimmune disorder. The time has come to acknowledge autoimmune cardiac arrhythmias as a distinct disease entity. Establishing the autoantibody profile of patients will help to develop novel treatment approaches for patients.
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Affiliation(s)
- Jin Li
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland. .,Department of Cardiology, Lausanne University Hospital, rue du Bugnon 46, 1011, Lausanne, Switzerland.
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4
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Beltrame SP, Carrera Páez LC, Auger SR, Sabra AH, Bilder CR, Waldner CI, Goin JC. Impairment of agonist-induced M 2 muscarinic receptor activation by autoantibodies from chagasic patients with cardiovascular dysautonomia. Clin Immunol 2020; 212:108346. [PMID: 31954803 DOI: 10.1016/j.clim.2020.108346] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 01/13/2020] [Accepted: 01/14/2020] [Indexed: 10/25/2022]
Abstract
Previous studies showed that circulating autoantibodies against M2 muscarinic receptors (anti-M2R Ab) are associated with decreased cardiac parasympathetic modulation in patients with chronic Chagas disease (CD). Here we investigated whether the exposure of M2R to such antibodies could impair agonist-induced receptor activation, leading to the inhibition of associated signaling pathways. Preincubation of M2R-expressing HEK 293T cells with serum IgG fractions from chagasic patients with cardiovascular dysautonomia, followed by the addition of carbachol, resulted in the attenuation of agonist-induced Gi protein activation and arrestin-2 recruitment. These effects were not mimicked by the corresponding Fab fractions, suggesting that they occur through receptor crosslinking. IgG autoantibodies did not enhance M2R/arrestin interaction or promote M2R internalization, suggesting that their inhibitory effects are not likely a result of short-term receptor regulation. Rather, these immunoglobulins could function as negative allosteric modulators of acetylcholine-mediated responses, thereby contributing to the development of parasympathetic dysfunction in patients with CD.
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Affiliation(s)
- Sabrina P Beltrame
- Laboratorio de Farmacología Molecular, Centro de Estudios Farmacológicos y Botánicos (CEFYBO-CONICET-UBA) and II Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 16, C1121ABG Buenos Aires, Argentina.
| | - Laura C Carrera Páez
- Laboratorio de Farmacología Molecular, Centro de Estudios Farmacológicos y Botánicos (CEFYBO-CONICET-UBA) and II Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 16, C1121ABG Buenos Aires, Argentina.
| | - Sergio R Auger
- Hospital D.F. Santojanni, Pilar 950, PB, C1408INH Buenos Aires, Argentina.
| | - Ahmad H Sabra
- Hospital D.F. Santojanni, Pilar 950, PB, C1408INH Buenos Aires, Argentina.
| | - Claudio R Bilder
- Laboratorio de Neurogastroenterología, Fundación Favaloro-Hospital Universitario, Av. Belgrano 1746, 1er Piso, C1093AAS Buenos Aires, Argentina.
| | - Claudia I Waldner
- Laboratorio de Inmunidad Celular y Molecular, Centro de Estudios Farmacológicos y Botánicos (CEFYBO-CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 16, C1121ABG Buenos Aires, Argentina.
| | - Juan C Goin
- Laboratorio de Farmacología Molecular, Centro de Estudios Farmacológicos y Botánicos (CEFYBO-CONICET-UBA) and II Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 16, C1121ABG Buenos Aires, Argentina.
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5
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Ribeiro KC, Campelo RP, Rodrigues DDRF, Mattos EC, Brandão IT, da Silva CL, Bouskela E, Martinez CG, Kurtenbach E. Immunization with plasmids encoding M2 acetylcholine muscarinic receptor epitopes impairs cardiac function in mice and induces autophagy in the myocardium. Autoimmunity 2018; 51:245-257. [PMID: 30424681 DOI: 10.1080/08916934.2018.1514389] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Autoantibodies against the M2 subtype of muscarinic acetylcholine receptors with functional activities have been found in the sera of patients with dilated cardiomyopathy (DCM), and the second extracellular loop has been established as the predominant epitope. However, it has been shown that the third intracellular loop is recognized by Chagas disease patients with severe cardiac dysfunction. In this work, BALB/c mice were immunized with plasmids encoding these two epitopes, and a control group received the empty plasmid (pcDNA3 vector). Serum from these DNA-immunized animals had elevated and persistent titres of antibodies against respective antigens. Heart echocardiography indicated diminished left ventricular wall thickness and reduced ejection fraction for both epitope-immunized groups, and ergospirometry tests showed a significant decrease in the exercise time and oxygen consumption. Transfer of serum from these immunized mice into naïve recipients induced the same alterations in cardiac structure and function. Furthermore, electron microscopy analysis of donor-immunized animals revealed several ultrastructural alterations suggestive of autophagy and mitophagy, suggesting novel roles for these autoantibodies. Overall, greater functional and structural impairment was observed in the donor and recipient epitope groups, implicating the third intracellular loop epitope in the pathological effects for the first-time. Therefore, the corresponding peptides could be useful for autoimmune DCM diagnosis and targeted therapy.
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Affiliation(s)
- Karla Consort Ribeiro
- a Programa de Biologia Molecular e Estrutural, Instituto de Biofísica Carlos Chagas Filho , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil.,b Instituto Nacional de Propriedade Industrial , Rio de Janeiro , Brazil
| | - Roberto Perez Campelo
- a Programa de Biologia Molecular e Estrutural, Instituto de Biofísica Carlos Chagas Filho , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil.,c Programa de Biologia Molecular e Biotecnologia, Instituto de Bioquímica Médica , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil
| | - Daniela Del Rosário Flores Rodrigues
- a Programa de Biologia Molecular e Estrutural, Instituto de Biofísica Carlos Chagas Filho , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil.,c Programa de Biologia Molecular e Biotecnologia, Instituto de Bioquímica Médica , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil
| | | | - Izaira Trincani Brandão
- e Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Célio Lopes da Silva
- e Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto , Universidade de São Paulo , Ribeirão Preto , Brazil
| | - Eliete Bouskela
- f Lab. Pesq. Clínicas e Experimentais em Biologia Vascular - BioVasc Inst. De Biologia Roberto Alcântara Gomes e Fac. de Ciências Médicas , Universidade do Estado do Rio de Janeiro , Rio de Janeiro , Brazil
| | - Camila Guerra Martinez
- a Programa de Biologia Molecular e Estrutural, Instituto de Biofísica Carlos Chagas Filho , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil.,g Instituto Nacional para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica , Conselho Nacional de Desenvolvimento Científico e Tecnológico/MCT , Rio de Janeiro , Brazil
| | - Eleonora Kurtenbach
- a Programa de Biologia Molecular e Estrutural, Instituto de Biofísica Carlos Chagas Filho , Universidade Federal do Rio de Janeiro , Rio de Janeiro , Brazil.,g Instituto Nacional para Pesquisa Translacional em Saúde e Ambiente na Região Amazônica , Conselho Nacional de Desenvolvimento Científico e Tecnológico/MCT , Rio de Janeiro , Brazil
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6
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Daliry A, Pereira IR, Pereira-Junior PP, Ramos IP, Vilar-Pereira G, Silvares RR, Lannes-Vieira J, Campos De Carvalho AC. Levels of circulating anti-muscarinic and anti-adrenergic antibodies and their effect on cardiac arrhythmias and dysautonomia in murine models of Chagas disease. Parasitology 2014; 141:1769-78. [PMID: 25093253 DOI: 10.1017/s0031182014001097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
SUMMARY Antibodies (Ab) recognizing G-protein coupled receptors, such as β 1 and β 2 adrenergic (anti-β 1-AR and anti-β 2-AR, respectively) and muscarinic cholinergic receptors (anti-M2-CR) may contribute to cardiac damage, however their role in chronic chagasic cardiomyopathy is still controversial. We describe that Trypanosoma cruzi-infected C3H/He mice show increased P and QRS wave duration, and PR and QTc intervals, while the most significant ECG alterations in C57BL/6 are prolonged P wave and PR interval. Echocardiogram analyses show right ventricle dilation in infected animals of both mouse lineages. Analyses of heart rate variability (HRV) in chronically infected C3H/He mice show no alteration of the evaluated parameters, while C57BL/6 infected mice display significantly lower values of HRV components, suggesting autonomic dysfunction. The time-course analysis of anti-β 1-AR, anti-β 2-AR and anti-M2-CR Ab titres in C3H/He infected mice indicate that anti-β 1-AR Ab are detected only in the chronic phase, while anti-β 2-AR and anti-M2-CR are observed in the acute phase, diminish at 60 dpi and increase again in the chronic phase. Chronically infected C57BL/6 mice presented a significant increase in only anti-M2-CR Ab titres. Furthermore, anti-β 1-AR, anti-β 2-AR and anti-M2-CR, exhibit significantly higher prevalence in chronically T. cruzi-infected C3H/He mice when compared with C57BL/6. These observations suggest that T. cruzi infection leads to host-specific cardiac electric alterations.
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Affiliation(s)
- Anissa Daliry
- Laboratório de Investigação Cardiovascular,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Isabela Resende Pereira
- Laboratório de Biologia das Interações,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Pedro Paulo Pereira-Junior
- Laboratório de Eletrofisiologia Cardíaca,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, UFRJ,Rio de Janeiro,Brazil
| | - Isalira Peroba Ramos
- Laboratório de Cardiologia Celular e Molecular,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, UFRJ,Rio de Janeiro,Brazil
| | - Glaucia Vilar-Pereira
- Laboratório de Biologia das Interações,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Raquel Rangel Silvares
- Laboratório de Investigação Cardiovascular,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Joseli Lannes-Vieira
- Laboratório de Biologia das Interações,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Antônio Carlos Campos De Carvalho
- Laboratório de Cardiologia Celular e Molecular,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, UFRJ,Rio de Janeiro,Brazil
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7
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Gimenez LE, Vishnivetskiy SA, Gurevich VV. Targeting individual GPCRs with redesigned nonvisual arrestins. Handb Exp Pharmacol 2014; 219:153-70. [PMID: 24292829 DOI: 10.1007/978-3-642-41199-1_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Numerous human diseases are caused by excessive signaling of mutant G protein-coupled receptors (GPCRs) or receptors that are overstimulated due to upstream signaling imbalances. The feasibility of functional compensation by arrestins with enhanced ability to quench receptor signaling was recently tested in the visual system. The results showed that even in this extremely demanding situation of rods that have no ability to phosphorylate rhodopsin, enhanced arrestin improved rod morphology, light sensitivity, survival, and accelerated photoresponse recovery. Structurally distinct enhanced mutants of arrestins that bind phosphorylated and non-phosphorylated active GPCRs with much higher affinity than parental wild-type (WT) proteins have been constructed. These "super-arrestins" are likely to have the power to dampen the signaling by hyperactive GPCRs. However, most cells express 5-20 GPCR subtypes, only one of which would be overactive, while nonvisual arrestins are remarkably promiscuous, binding hundreds of different GPCRs. Thus, to be therapeutically useful, enhanced versions of nonvisual arrestins must be made fairly specific for particular receptors. Recent identification of very few arrestin residues as key receptor discriminators paves the way to the construction of receptor subtype-specific nonvisual arrestins.
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Affiliation(s)
- Luis E Gimenez
- Department of Pharmacology, Vanderbilt University, 2200 Pierce Avenue, Nashville, TN, 37232, USA,
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8
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Neves BCD, Bacilio ML, Berrueta L, Salmen S, Peterson DL, Donis JH, Nuñez TJ, Davila DF. Muscarinic antibodies and heart rate responses to dynamic exercise and to the Valsalva maneuver in chronic chagasic patients. Rev Inst Med Trop Sao Paulo 2013; 55:31-7. [PMID: 23328723 DOI: 10.1590/s0036-46652013000100006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Accepted: 08/14/2012] [Indexed: 11/22/2022] Open
Abstract
We have studied the cardiac chronotropic responses to the Valsalva maneuver and to dynamic exercise of twenty chronic chagasic patients with normal left ventricular function and no segmental wall abnormalities by two-dimensional echocardiogram. The absolute increase in heart rate of the patients (Δ = 21.5 ± 10 bpm, M±SD) during the maneuver was significantly diminished when compared to controls (Δ = 31.30 ± 70, M±SD, p = 0.03). The minimum heart rate (58.24 ± 8.90 vs. 62.80 ± 10, p = 0.68) and the absolute decrease in heart rate at the end of the maneuver (Δ = 38.30 ± 13 vs. Δ = 31.47 ± 17, p = 0.10) were not different from controls. The initial heart rate acceleration during dynamic exercise (Δ = 12 ± 7.55 vs. Δ = 19 ± 7.27, M±SD, p = 0.01) was also diminished, but the heart rate recovery during the first ten seconds was more prominent in the sero-positive patients (Median: 14, Interquartile range: (9.75-17.50 vs. 5(0-8.75, p = 0.001). The serum levels of muscarinic cardiac auto-antibodies were significantly higher in the chagasic patients (Median: 34.58, Interquartile Range: 17-46.5, Optical Density) than in controls (Median: 0, Interquartile Range: 0-22.25, p = 0.001) and correlated significantly and directly (r = 0.68, p = 0.002) with early heart rate recovery during dynamic exercise. The results of this investigation indirectly suggest that, the cardiac muscarinic auto-antibodies may have positive agonist effects on parasympathetic heart rate control of chagasic patients.
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Affiliation(s)
- Barbara C das Neves
- Instituto de Investigaciones Cardiovasculares, Universidad de Los Andes, Mérida, Venezuela
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9
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Dávila DF, Donis JH, Arata de Bellabarba G, Villarroel V, Sanchez F, Berrueta L, Salmen S, Das Neves B. Cardiac autonomic control mechanisms in the pathogenesis of chagas' heart disease. Interdiscip Perspect Infect Dis 2012; 2012:980739. [PMID: 23091486 PMCID: PMC3467757 DOI: 10.1155/2012/980739] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/27/2012] [Indexed: 11/17/2022] Open
Abstract
Primary abnormalities of the autonomic nervous system had been postulated as the pathogenic mechanisms of myocardial damage, in patients with Chagas disease. However, recent investigations indicate that these abnormalities are secondary and amenable to treatment with beta-adrenergic blockers. Moreover, muscarinic cardiac autoantibodies appear to enhance parasympathetic activity on the sinus node. Therefore, the purpose of this paper is to analyze how knowledge on Chagas' disease evolved from being initially considered as a primary cardioneuromyopathy to the current status of a congestive cardiomyopathy of parasitic origin.
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Affiliation(s)
- Diego F. Dávila
- Instituto de Investigaciones Cardiovasculares, Departamento de Fisiopatología, Instituto de Inmunologìa Clinica, Facultad de Medicina, Hospital Universitario de Los Andes, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Jose H. Donis
- Instituto de Investigaciones Cardiovasculares, Departamento de Fisiopatología, Instituto de Inmunologìa Clinica, Facultad de Medicina, Hospital Universitario de Los Andes, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Gabriela Arata de Bellabarba
- Instituto de Investigaciones Cardiovasculares, Departamento de Fisiopatología, Instituto de Inmunologìa Clinica, Facultad de Medicina, Hospital Universitario de Los Andes, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Vanesa Villarroel
- Instituto de Investigaciones Cardiovasculares, Departamento de Fisiopatología, Instituto de Inmunologìa Clinica, Facultad de Medicina, Hospital Universitario de Los Andes, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Francisco Sanchez
- Instituto de Investigaciones Cardiovasculares, Departamento de Fisiopatología, Instituto de Inmunologìa Clinica, Facultad de Medicina, Hospital Universitario de Los Andes, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Lisbeth Berrueta
- Instituto de Investigaciones Cardiovasculares, Departamento de Fisiopatología, Instituto de Inmunologìa Clinica, Facultad de Medicina, Hospital Universitario de Los Andes, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Siham Salmen
- Instituto de Investigaciones Cardiovasculares, Departamento de Fisiopatología, Instituto de Inmunologìa Clinica, Facultad de Medicina, Hospital Universitario de Los Andes, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Barbara Das Neves
- Instituto de Investigaciones Cardiovasculares, Departamento de Fisiopatología, Instituto de Inmunologìa Clinica, Facultad de Medicina, Hospital Universitario de Los Andes, Universidad de Los Andes, Mérida 5101, Venezuela
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10
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Niu L, Guo C, Hao Z, Yuan J, Li Z. Potential roles of recombinant acetylcholine receptor α subunit 1–211 in immunoadsorbent and DNA immunization. J Immunol Methods 2011; 372:14-21. [DOI: 10.1016/j.jim.2011.04.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2011] [Accepted: 04/05/2011] [Indexed: 10/17/2022]
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11
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Lee HC, Huang KTL, Wang XL, Shen WK. Autoantibodies and cardiac arrhythmias. Heart Rhythm 2011; 8:1788-95. [PMID: 21740882 DOI: 10.1016/j.hrthm.2011.06.032] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 06/21/2011] [Indexed: 11/19/2022]
Abstract
Autoimmune diseases are associated with significant morbidity and mortality, afflicting about 5% of the US population. They encompass a wide range of disorders that affect all organs of the human body and have a predilection for women. In the past, autoimmune pathogenesis was not thought to be a major mechanism for cardiovascular disorders, and potential relationships remain understudied. However, accumulating evidence suggests that a number of vascular and cardiac conditions are autoimmune mediated. Recent studies indicate that autoantibodies play an important role in the development of cardiac arrhythmias, including atrial fibrillation, modulation of autonomic influences on heart rate and rhythm, conduction system abnormalities, and ventricular arrhythmias. This article will review the current evidence for the role of autoantibodies in the development of cardiac arrhythmias.
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Affiliation(s)
- Hon-Chi Lee
- Department of Internal Medicine, Division of Cardiovascular Diseases, Mayo Clinic Rochester, Rochester, Minnesota 55905, USA.
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12
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Antibodies against the Trypanosoma cruzi ribosomal P proteins induce apoptosis in HL-1 cardiac cells. Int J Parasitol 2011; 41:635-44. [DOI: 10.1016/j.ijpara.2010.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 12/21/2010] [Accepted: 12/22/2010] [Indexed: 11/30/2022]
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13
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Beltrame SP, Auger SR, Bilder CR, Waldner CI, Goin JC. Modulation of M(2) muscarinic receptor-receptor interaction by immunoglobulin G antibodies from Chagas' disease patients. Clin Exp Immunol 2011; 164:170-9. [PMID: 21391990 DOI: 10.1111/j.1365-2249.2011.04370.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Circulating immunoglobulin (Ig)G antibodies against M(2) muscarinic acetylcholine receptors (M(2) mAChR) have been implicated in Chagas' disease (ChD) pathophysiology. These antibodies bind to and activate their target receptor, displaying agonist-like activity through an unclear mechanism. This study tested the ability of serum anti-M(2) mAChR antibodies from chronic ChD patients to modulate M(2) muscarinic receptor-receptor interaction by bioluminescence resonance energy transfer (BRET). Human embryonic kidney (HEK) 293 cells co-expressing fusion proteins M(2) mAChR-Renilla luciferase (RLuc) and M(2) mAChR-yellow fluorescent protein (YFP) were exposed to the serum IgG fraction from ChD patients, and BRET between RLuc and YFP was assessed by luminometry. Unlike serum IgG from healthy subjects and conventional muscarinic ligands, ChD IgG promoted a time- and concentration-dependent increase in the BRET signal. This effect neither required cellular integrity nor occurred as a consequence of receptor activation. Enhancement of M(2) receptor-receptor interaction by ChD IgG was receptor subtype-specific and mediated by the recognition of the second extracellular loop of the M(2) mAChR. The monovalent Fab fragment derived from ChD IgG was unable to reproduce the effect of the native immunoglobulin. However, addition of ChD Fab in the presence of anti-human Fab IgG restored BRET-enhancing activity. These data suggest that the modulatory effect of ChD IgG on M(2) receptor-receptor interaction results from receptor cross-linking by bivalent antibodies.
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Affiliation(s)
- S P Beltrame
- Laboratorio de Farmacología Molecular, Centro de Estudios Farmacológicos y Botánicos (CEFYBO-CONICET-UBA)
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14
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De Amici M, Dallanoce C, Holzgrabe U, Tränkle C, Mohr K. Allosteric ligands for G protein-coupled receptors: a novel strategy with attractive therapeutic opportunities. Med Res Rev 2010; 30:463-549. [PMID: 19557759 DOI: 10.1002/med.20166] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Allosteric receptor ligands bind to a recognition site that is distinct from the binding site of the endogenous messenger molecule. As a consequence, allosteric agents may attach to receptors that are already transmitter-bound. Ternary complex formation opens an avenue to qualitatively new drug actions at G protein-coupled receptors (GPCRs), in particular receptor subtype selective potentiation of endogenous transmitter action. Consequently, suitable exploitation of allosteric recognition sites as alternative molecular targets could pave the way to a drug discovery paradigm different from those aimed at mimicking or blocking the effects of endogenous (orthosteric) receptor activators. The number of allosteric ligands reported to modulate GPCR function is steadily increasing and some have already reached routine clinical use. This review aims at introducing into this fascinating field of drug discovery and at providing an overview about the achievements that have already been made. Various case examples will be discussed in the framework of GPCR classification (family A, B, and C receptors). In addition, the behavior at muscarinic receptors of hybrid derivatives incorporating both an allosteric and an orthosteric fragment in a common molecular skeleton will be illustrated.
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Affiliation(s)
- Marco De Amici
- Department of Pharmaceutical Sciences Pietro Pratesi, University of Milan, via Mangiagalli 25, 20133 Milano, Italy.
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15
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Negroni MP, Fiszman GL, Azar ME, Morgado CC, Español AJ, Pelegrina LT, de la Torre E, Sales ME. Immunoglobulin G from breast cancer patients in stage I stimulates muscarinic acetylcholine receptors in MCF7 cells and induces proliferation. Participation of nitric oxide synthase-derived nitric oxide. J Clin Immunol 2010; 30:474-84. [PMID: 20157846 DOI: 10.1007/s10875-010-9370-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Accepted: 01/07/2010] [Indexed: 01/25/2023]
Abstract
INTRODUCTION Muscarinic acetylcholine receptors (mAChR) belong to the G-protein-coupled receptor family and are extensively expressed in most cells in mammals. We had reported the expression of mAChR in murine and human breast tumors. METHODS The presence of antibodies in the sera of patients with different tumors directed against self-proteins has been recently described. In this work, we investigated the presence of autoantibodies against mAChR in the sera of breast cancer patients in stage I (T1N0Mx-IgG). IgG purification was performed by affinity chromatography in protein G-agarose. We also studied the ability of these antibodies to modulate the proliferation of MCF-7 breast tumor cells by the MTS colorimetric assay. The ability of T1N0Mx-IgG to stimulate muscarinic signaling pathway via nitric oxide synthase was tested by Griess reaction. RESULTS We demonstrated M(3) and M(4) receptors expression in MCF-7 cells. T1N0Mx-IgG promotes cell proliferation, mimicking the action of the muscarinic agonist carbachol. This effect was preferentially due to M(3) receptor activation in tumor cells via phospholipase C-induced nitric oxide liberation by calcium-dependent nitric oxide synthases. IgG from control patients was unable to produce this effect. DISCUSSION IgG from patients with breast cancer in early stages could be promoting tumor progression by muscarinic activation, and its presence could be determining the prognosis of this illness.
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Affiliation(s)
- María Pía Negroni
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155 piso 16, CP 1121 Ciudad Autónoma de Buenos Aires, Argentina
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Mohr K, Tränkle C, Kostenis E, Barocelli E, De Amici M, Holzgrabe U. Rational design of dualsteric GPCR ligands: quests and promise. Br J Pharmacol 2010; 159:997-1008. [PMID: 20136835 DOI: 10.1111/j.1476-5381.2009.00601.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Dualsteric ligands represent a novel mode of targeting G protein-coupled receptors (GPCRs). These compounds attach simultaneously to both, the orthosteric transmitter binding site and an additional allosteric binding area of a receptor protein. This approach allows the exploitation of favourable characteristics of the orthosteric and the allosteric site by a single ligand molecule. The orthosteric interaction provides high affinity binding and activation of receptors. The allosteric interaction yields receptor subtype-selectivity and, in addition, may modulate both, efficacy and intracellular signalling pathway activation. Insight into the spatial arrangement of the orthosteric and the allosteric site is far advanced in the muscarinic acetylcholine receptor, and the design of dualsteric muscarinic agonists has now been accomplished. Using the muscarinic receptor as a paradigm, this review summarizes the way from suggestive evidence for an orthosteric/allosteric overlap binding to the rational design and experimental validation of dualsteric ligands. As allosteric interactions are increasingly described for GPCRs and as insight into the spatial geometry of ligand/GPCR-complexes is growing impressively, the rational design of dualsteric drugs is a promising new approach to achieve fine-tuned GPCR-modulation.
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Affiliation(s)
- Klaus Mohr
- Institute of Pharmacy, Rheinische Friedrich-Wilhelms-University, Bonn, Germany.
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Borrás SG, Racca L, Cotorruelo C, Biondi C, Beloscar J, Racca A. Distribution ofHLA-DRB1Alleles in Argentinean Patients with Chagas' Disease Cardiomyopathy. Immunol Invest 2009; 38:268-75. [DOI: 10.1080/08820130902766589] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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