Cardiac effects of long-term active immunization with the second extracellular loop of human β1- and/or β3-adrenoceptors in Lewis rats.
β1- and β3-adrenoceptor (AR) auto-antibodies were detected in patients with dilated cardiomyopathy. Many studies have shown that β1-AR auto-antibodies with partial agonist-like effect play an important role in the pathogenesis of this disease. Moreover, a recent study carried out in our laboratory has shown that β3-AR antibodies (β3-ABs), produced in rats, were able to reduce cardiomyocyte contractility via β3-AR activation. The aims of this study were (1) to investigate, in isolated cardiomyocytes from rabbit, the role of Gi proteins in the β3-ABs-induced cardiac negative inotropy, (2) to determine whether β3-ABs may exhibit β3-AR antagonistic property which is characteristic of partial agonists, and (3) to determine whether long-term active immunization producing both β1-ABs and/or β3-ABs leads to the development of cardiac dysfunction in Lewis rats. Lewis rats were immunized for 6 months with peptidic sequences corresponding to the second extracellular loop of human β3-AR and/or β1-AR. Agonistic effect of β3-ABs was evaluated on electrically field-stimulated isolated cardiomyocytes from adult rabbit by measuring the cell shortening. Echocardiography and ex vivo isolated perfused heart studies were conducted on immunized rats. Finally, β-AR expression was quantified by immunofluorescence and RT-qPCR. SR58611A (10 nM), a preferential β3-AR agonist, and purified β3-ABs (25 μg/ml) induced a decrease in cell shortening (-39.71±4.9% (n=10) and -17.06±3.9% (n=10) respectively). This effect was significantly inhibited when the cardiomyocytes were preincubated with pertussis toxin (0.3 μg/ml), a Gi protein inhibitor (p<0.05). In addition, SR58611A-mediated negative inotropic effect was decreased when cardiomyocytes were preincubated with β3-ABs (p<0.0001). Echocardiography revealed a decrease in the fractional shortening and ejection fraction in rats immunized against β1-AR and both β1- and β3-AR. However, the study on isolated heart showed a decrease of the isoproterenol-induced lusitropic and inotropic effects in the 3 groups of immunized rats. These systolic and diastolic dysfunctions are correlated with a decrease in the expression of β1-ARs and an increase of β3-ARs in rats immunized against the β1-AR and an increase of both β3-AR and β1-AR in rats immunized against the β3-AR. For the first time, these results showed that β3-ABs had a β3-AR partial agonist-like activity which might play a role in the pathogenesis of cardiac dysfunction.
LUNAM University, Oniris, UPSP 5304 of Animal Pathophysiology and Functional Pharmacology, Atlanpôle La Chantrerie, BP 40706, 44307 Nantes, France.
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Montaudon
LUNAM University, Oniris, INRA UMR U703, PanTHER, Atlanpôle La Chantrerie, BP 40706, 44307 Nantes, France.
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Dubreil
LUNAM University, Oniris, UPSP 5304 of Animal Pathophysiology and Functional Pharmacology, Atlanpôle La Chantrerie, BP 40706, 44307 Nantes, France.
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Lalanne
LUNAM University, Oniris, UPSP 5304 of Animal Pathophysiology and Functional Pharmacology, Atlanpôle La Chantrerie, BP 40706, 44307 Nantes, France.
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Vermot Des Roches
LUNAM University, INSERM, UMR 1087/CNRS 6291, Institut du Thorax, Nantes F44007 France.
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Toumaniantz
LUNAM University, Oniris, INSERM UMR_S 791, LIOAD, Atlanpôle La Chantrerie, BP 40706, 44307 Nantes, France.
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Fusellier
LUNAM University, Oniris, UPSP 5304 of Animal Pathophysiology and Functional Pharmacology, Atlanpôle La Chantrerie, BP 40706, 44307 Nantes, France.
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Desfontis
LUNAM University, Oniris, UPSP SSBR, Atlanpôle La Chantrerie, BP 40706, 44307 Nantes, France.
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Martignat
LUNAM University, Oniris, UPSP 5304 of Animal Pathophysiology and Functional Pharmacology, Atlanpôle La Chantrerie, BP 40706, 44307 Nantes, France. Electronic address: yassine.mallem@oniris-nantes.fr.
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Mallem
D000818:Animals; D009202:Cardiomyopathies / Q000188:drug therapy / Q000276:immunology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects / Q000276:immunology; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000276:immunology*; D037342:Pertussis Toxin / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D011917:Rats, Inbred Lew; D022702:Receptors, Adrenergic, beta-3 / Q000276:immunology*; D014611:Vaccination / Q000379:methods
D022702:Receptors, Adrenergic, beta-3; D037342:Pertussis Toxin; D007545:Isoproterenol
Auto-antibodies; Cardiac contractility; Dilated cardiomyopathy; Rats; β-Adrenoceptor