title: Natural thermal adaptation increases heat shock protein levels and decreases oxidative stress.
abstract: Heat shock proteins (HSPs), originally identified as heat-inducible gene products, are a family of highly conserved proteins that respond to a wide variety of stress including oxidative stress. Although both acute and chronic oxidative stress have been well demonstrated to induce HSP responses, little evidence is available whether increased HSP levels provide enhanced protection against oxidative stress under elevated yet sublethal temperatures. We studied relationships between oxidative stress and HSPs in a physiological model by using Garra rufa (doctor fish), a fish species naturally acclimatized to different thermal conditions. We compared fish naturally living in a hot spring with relatively high water temperature (34.4±0.6°C) to those living in normal river water temperature (25.4±4.7°C), and found that levels of all the studied HSPs (HSP70, HSP60, HSP90, HSC70 and GRP75) were higher in fish living in elevated water temperature compared with normal river water temperature. In contrast, indicators of oxidative stress, including protein carbonyls and lipid hydroperoxides, were decreased in fish living in the elevated temperature, indicating that HSP levels are inversely associated with oxidative stress. The present results provide evidence that physiologically increased HSP levels provide protection against oxidative stress and enhance cytoprotection.
authors.affiliation: Institute of Biomedicine, Department of Physiology, University of Eastern Finland, Kuopio, Finland; Department of Surgery, Medical School, University of Tampere and Tampere University Hospital, Tampere, Finland.
authors.forename: Niku K J
authors.initials: NK
authors.lastname: Oksala
authors.affiliation: Department of Biology, Faculty of Science, University of Hacettepe, Beytepe, Turkey.
authors.forename: F Güler
authors.initials: FG
authors.lastname: Ekmekçi
authors.affiliation: Department of Biology, Faculty of Science, University of Hacettepe, Beytepe, Turkey.
authors.forename: Ergi
authors.initials: E
authors.lastname: Ozsoy
authors.affiliation: Department of Biology, Faculty of Science and Literature, University of Düzce, Düzce, Turkey.
authors.forename: Serife
authors.initials: S
authors.lastname: Kirankaya
authors.affiliation: Institute of Biomedicine, Department of Physiology, University of Eastern Finland, Kuopio, Finland; School of Pharmacy, University of Eastern Finland, Kuopio, Finland.
authors.forename: Tarja
authors.initials: T
authors.lastname: Kokkola
authors.affiliation: Department of Biology, Faculty of Science, University of Hacettepe, Beytepe, Turkey.
authors.forename: Güzin
authors.initials: G
authors.lastname: Emecen
authors.affiliation: Institute of Biomedicine, Department of Physiology, University of Eastern Finland, Kuopio, Finland.
authors.forename: Jani
authors.initials: J
authors.lastname: Lappalainen
authors.affiliation: Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Finland; Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Kai
authors.initials: K
authors.lastname: Kaarniranta
authors.affiliation: Institute of Biomedicine, Department of Physiology, University of Eastern Finland, Kuopio, Finland. Electronic address: mustafa.atalay@uef.fi.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Atalay
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D005399:Fishes / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism*; D018384:Oxidative Stress; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D006360:Heat-Shock Proteins; D014867:Water
keywords: Garra rufa; Oxidation; Regulation; Stress; Thermal