Calcitonin gene-related peptide partly protects cultured smooth muscle cells from apoptosis induced by an oxidative stress via activation of ERK1/2 MAPK.
Oxidative stress induced by a glucose/glucose oxidase (G/GO) generator system dose-dependently decreased the viability of cultured vascular smooth muscle cells (VSMC) as estimated by MTT assay. Cell death was induced in 40% of cells exposed to 0.2 IU/ml of the free radical generating mixture. Annexin-V labeling, Hoechst staining together with DNA laddering demonstrated that apoptosis was responsible for this cell loss. Pretreatment of the cells with 10(-8) M calcitonin gene-related peptide (CGRP) significantly attenuated the damaging effect of the oxidative stress. Indeed, cell viability was estimated to be 80% in CGRP-treated group, instead of 60% in absence of CGRP treatment. This protective effect of CGRP was antagonized by 8-37 CGRP, an antagonist of CGRP-1 receptors, whereas it was not reproduced by amylin, a CGRP analogue. As indicated by the reduction in Hoechst staining and in DNA laddering, CGRP prevented the onset of apoptosis. We also demonstrated that the peptide significantly up-regulated the activation of ERK1/2 and P38 kinases. Inhibitors of the kinases prevented the protective effect of CGRP. We conclude that CGRP antagonizes oxidative stress-induced apoptosis by up-regulating MAP kinase activation and that activation of these kinases was necessary to protection.
Schaeffer
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Faculté des Sciences Gabriel, Laboratoire de Physiopathologie et Pharmacologie Cardiovasculaires Expérimentales, Biologie Animale Cellulaire et Moléculaire, Université de Bourgogne, IFR Santé 100, 21000, Dijon, France. Celine.Schaeffer@u-bourgogne.fr
Vandroux
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Thomassin
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Athias
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Rochette
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Connat
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D000818:Animals; D017209:Apoptosis; D015740:Calcitonin Gene-Related Peptide / Q000502:physiology*; D002478:Cells, Cultured; D006801:Humans; D006861:Hydrogen Peroxide; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress; D020011:Protective Agents; D051381:Rats; D017208:Rats, Wistar; D018015:Receptors, Calcitonin Gene-Related Peptide / Q000502:physiology; D015398:Signal Transduction; D015854:Up-Regulation
D020011:Protective Agents; D018015:Receptors, Calcitonin Gene-Related Peptide; D006861:Hydrogen Peroxide; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D015740:Calcitonin Gene-Related Peptide