title: High hydrostatic pressure influences the in vitro response to xenobiotics in Dicentrarchus labrax liver.
abstract: Hydrostatic pressure (HP) increases by about 1 atmosphere (0.1MPa) for each ten-meter depth increase in the water column. This thermodynamical parameter could well influence the response to and effects of xenobiotics in the deep-sea biota, but this possibility remains largely overlooked. To grasp the extent of HP adaptation in deep-sea fish, comparative studies with living cells of surface species exposed to chemicals at high HP are required. We initially conducted experiments with precision-cut liver slices of a deep-sea fish (Coryphaenoides rupestris), co-exposed for 15h to the aryl hydrocarbon receptor (AhR) agonist 3-methylcholanthrene at HP levels representative of the surface (0.1MPa) and deep-sea (5-15MPa; i.e., 500-1500m depth) environments. The transcript levels of a suite of stress-responsive genes, such as the AhR battery CYP1A, were subsequently measured (Lemaire et al., 2012; Environ. Sci. Technol. 46, 10310-10316). Strikingly, the AhR agonist-mediated increase of CYP1A mRNA content was pressure-dependently reduced in C. rupestris. Here, the same co-exposure scenario was applied for 6 or 15h to liver slices of a surface fish, Dicentrarchus labrax, a coastal species presumably not adapted to high HP. Precision-cut liver slices of D. labrax were also used in 1h co-exposure studies with the pro-oxidant tert-butylhydroperoxide (tBHP) as to investigate the pressure-dependence of the oxidative stress response (i.e., reactive oxygen production, glutathione and lipid peroxidation status). Liver cells remained viable in all experiments (adenosine triphosphate content). High HP precluded the AhR agonist-mediated increase of CYP1A mRNA expression in D. labrax, as well as that of glutathione peroxidase, and significantly reduced that of heat shock protein 70. High HP (1h) also tended per se to increase the level of oxidative stress in liver cells of the surface fish. Trends to an increased resistance to tBHP were also noted. Whether the latter observation truly reflects a protective response to oxidative stress will be addressed in future co-exposure studies with both surface and deep-sea fish liver cells, using additional pro-oxidant chemicals. Altogether, data on CYP1A inducibility with D. labrax and C. rupestris support the view that high HP represses AhR signaling in marine fishes, and that only species adapted to thrive in the deep-sea have evolved the molecular adaptations necessary to counteract to some extent this inhibition.
authors.affiliation: Institut des Sciences de la Vie, Université Catholique de Louvain, Croix du Sud 2, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lemaire
authors.affiliation: Institut des Sciences de la Vie, Université Catholique de Louvain, Croix du Sud 2, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Mignolet
authors.affiliation: Institut des Sciences de la Vie, Université Catholique de Louvain, Croix du Sud 2, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Cathy
authors.initials: C
authors.lastname: Debier
authors.affiliation: Louvain Drug Research Institute, Université Catholique de Louvain, Avenue Mounier 73, B-1200 Woluwé-Saint-Lambert, Belgium.
authors.forename: Pedro Buc
authors.initials: PB
authors.lastname: Calderon
authors.affiliation: Laboratoire d'Ecologie Animale et Ecotoxicologie, Université de Liège, Allée du 6 août 15, B-4000 Liège, Belgium.
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Thomé
authors.affiliation: Institut des Sciences de la Vie, Université Catholique de Louvain, Croix du Sud 2, B-1348 Louvain-la-Neuve, Belgium. Electronic address: jf.rees@uclouvain.be.
authors.forename: Jean François
authors.initials: JF
authors.lastname: Rees
mesh_terms: D000818:Animals; D001492:Bass / Q000502:physiology*; D029941:Fish Proteins / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D006874:Hydrostatic Pressure; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000187:drug effects*; D008748:Methylcholanthrene / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity; D015262:Xenobiotics / Q000633:toxicity*
chemical_list: D029941:Fish Proteins; D018336:Receptors, Aryl Hydrocarbon; D014874:Water Pollutants, Chemical; D015262:Xenobiotics; D008748:Methylcholanthrene; D005979:Glutathione Peroxidase; D005978:Glutathione
keywords: CYP1A; Fish; Heat shock proteins; Hydrostatic pressure; Oxidative stress; Precision-cut liver slices