title: Accumulation of heme oxygenase-1 (HSP32) in Xenopus laevis A6 kidney epithelial cells treated with sodium arsenite, cadmium chloride or proteasomal inhibitors.
abstract: The present study examined the effect of sodium arsenite, cadmium chloride, heat shock and the proteasomal inhibitors MG132, withaferin A and celastrol on heme oxygenase-1 (HO-1; also known as HSP32) accumulation in Xenopus laevis A6 kidney epithelial cells. Immunoblot analysis revealed that HO-1 accumulation was not induced by heat shock but was enhanced by sodium arsenite and cadmium chloride in a dose- and time-dependent fashion. Immunocytochemistry revealed that these metals induced HO-1 accumulation in a granular pattern primarily in the cytoplasm. Additionally, in 20% of the cells arsenite induced the formation of large HO-1-containing perinuclear structures. In cells recovering from sodium arsenite or cadmium chloride treatment, HO-1 accumulation initially increased to a maximum at 12h followed by a 50% reduction at 48 h. This initial increase in HO-1 levels was likely the result of new synthesis as it was inhibited by cycloheximide. Interestingly, treatment of cells with a mild heat shock enhanced HO-1 accumulation induced by low concentrations of sodium arsenite and cadmium chloride. Finally, we determined that HO-1 accumulation was induced in A6 cells by the proteasomal inhibitors, MG132, withaferin A and celastrol. An examination of heavy metal and proteasomal inhibitor-induced HO-1 accumulation in amphibians is of importance given the presence of toxic heavy metals in aquatic habitats.
authors: Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
authors: Ena
authors: E
authors: Music
authors: Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
authors: Saad
authors: S
authors: Khan
authors: Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
authors: Imran
authors: I
authors: Khamis
authors: Department of Biology, University of Waterloo, Waterloo, Ontario, Canada. Electronic address: heikkila@uwaterloo.ca.
authors: John J
authors: JJ
authors: Heikkila
mesh_terms: D000818:Animals; D018053:Arsenites / Q000494:pharmacology* / Q000633:toxicity; D019256:Cadmium Chloride / Q000494:pharmacology* / Q000633:toxicity; D002460:Cell Line; D022083:Cytoplasmic Structures / Q000187:drug effects / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D050890:HSP30 Heat-Shock Proteins / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature / Q000009:adverse effects; D007150:Immunohistochemistry; D007668:Kidney / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007976:Leupeptins / Q000494:pharmacology; D053978:Pentacyclic Triterpenes; D061988:Proteasome Inhibitors / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects; D017670:Sodium Compounds / Q000494:pharmacology* / Q000633:toxicity; D023382:Toxicity Tests, Acute; D014315:Triterpenes / Q000494:pharmacology; D014874:Water Pollutants, Chemical / Q000494:pharmacology* / Q000633:toxicity; D054358:Withanolides / Q000494:pharmacology; D029867:Xenopus Proteins / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D018053:Arsenites; D050890:HSP30 Heat-Shock Proteins; D007976:Leupeptins; D053978:Pentacyclic Triterpenes; D061988:Proteasome Inhibitors; D017670:Sodium Compounds; D014315:Triterpenes; D014874:Water Pollutants, Chemical; D054358:Withanolides; D029867:Xenopus Proteins; C494391:hsp30 protein, Xenopus; C017947:sodium arsenite; D051547:Heme Oxygenase-1; D019256:Cadmium Chloride; C009684:withaferin A; C050414:celastrol; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde
keywords: Amphibian; Cadmium chloride; Confocal microscopy; Frog; Heat shock proteins; Molecular chaperone; Sodium arsenite