title: Acute thermal stress and various heavy metals induce tissue-specific pro- or anti-apoptotic events via the p38-MAPK signal transduction pathway in Mytilus galloprovincialis (Lam.).
abstract: We investigated the effects of various heavy metals such as copper, zinc and cadmium, as well as acute thermal stress, on the signalling mechanisms involved in the protection and/or apoptosis of Mytilus galloprovincialis mantle and gill tissues. The results of our studies revealed that mantle and gill tissues differentially respond to the stressful stimuli examined. In the mantle tissue, 1 micromol l(-1) Cu2+ and 50 micromol l(-1) Zn2+ induced a transient p38-MAPK activation, whereas 1 micromol l(-1) Cd2+ induced a biphasic profile of the kinase phosphorylation with maximal values at 15 and 120 min of treatment, respectively. Furthermore, 1 micromol l(-1) SB203580 abolished the Cu2+-induced kinase phosphorylation. In gills, both Cu2+ and Zn2+ induced a considerably higher p38-MAPK activation, which remained elevated for at least 60 min, whereas Cd2+ induced a maximal kinase activation within 60 min of treatment. Hypothermia (4 degrees C) induced a moderate kinase phosphorylation (maximised at 30 min), whereas hyperthermia (30 degrees C) induced a rapid (within 15 min) p38-MAPK phosphorylation that remained considerably above basal levels for at least 2 h. Our studies on the synergistic effect of hyperthermia and Cu2+ revealed that these two stressful stimuli are additive in the mantle tissue, inducing an almost double p38-MAPK activation. Further studies on the involvement of the p38-MAPK signalling pathway in tissue-specific pro- or anti-apoptotic events revealed that identical stressful stimuli possibly lead to apoptotic death via the caspase-3 activation in the mantle tissue and to anti-apoptotic events possibly via the induction of Hsp70 overexpression in the gill tissue.
authors.affiliation: Department of Animal and Human Physiology, School of Biology, Faculty of Sciences, University of Athens, Panepistimioupolis, Athens 157 84, Greece.
authors.forename: Erene
authors.initials: E
authors.lastname: Kefaloyianni
authors.forename: Eleni
authors.initials: E
authors.lastname: Gourgou
authors.forename: Vanessa
authors.initials: V
authors.lastname: Ferle
authors.forename: Efstathios
authors.initials: E
authors.lastname: Kotsakis
authors.forename: Catherine
authors.initials: C
authors.lastname: Gaitanaki
authors.forename: Isidoros
authors.initials: I
authors.lastname: Beis
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006115:Greece; D018882:Heat Stress Disorders / Q000503:physiopathology*; D015151:Immunoblotting; D008297:Male; D019216:Metals, Heavy / Q000633:toxicity*; D049878:Mytilus / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013696:Temperature; D013997:Time Factors; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D019216:Metals, Heavy; D048051:p38 Mitogen-Activated Protein Kinases; D053148:Caspase 3; D020169:Caspases