title: Redox signaling of cardiac HSF1 DNA binding.
abstract: Experiments involving chemical induction of the heat shock response in simple biological systems have generated the hypothesis that protein denaturation and consequential binding of heat shock transcription factor 1 (HSF1) to proximal heat shock elements (HSEs) on heat shock protein (hsp) genes are the result of oxidation and/or depletion of intracellular thiols. The purpose of the present investigation was to determine the role of redox signaling of HSF1 in the intact animal in response to physiological and pharmacological perturbations. Heat shock and exercise induced HSF1-HSE DNA binding in the rat myocardium (P < 0.001) in the absence of changes in reduced glutathione (GSH), the major nonprotein thiol in the cell. Ischemia-reperfusion, which decreased GSH content (P < 0.05), resulted in nonsignificant HSF1-HSE formation. This dissociation between physiological induction of HSF1 and changes in GSH was not gender dependent. Pharmacological ablation of GSH with L-buthionine-[S,R]-sulfoximine (BSO) treatment increased myocardial HSF1-HSE DNA binding in estrogen-naive animals (P = 0.007). Thus, although physiological induction of HSF1-HSE DNA binding is likely regulated by mediators of protein denaturation other than cellular redox status, the proposed signaling pathway may predominate with pharmacological oxidation and may represent a plausible and accessible strategy in the development of HSP-based therapies.
authors.affiliation: School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada N6A 3K7.
authors.forename: Zain
authors.initials: Z
authors.lastname: Paroo
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Meredith
authors.forename: Marius
authors.initials: M
authors.lastname: Locke
authors.forename: James V
authors.initials: JV
authors.lastname: Haist
authors.forename: Morris
authors.initials: M
authors.lastname: Karmazyn
authors.forename: Earl G
authors.initials: EG
authors.lastname: Noble
mesh_terms: D000818:Animals; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D002423:Cause of Death; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D005260:Female; D005978:Glutathione / Q000037:antagonists & inhibitors / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000235:genetics; D006358:Hot Temperature; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009206:Myocardium / Q000378:metabolism*; D010052:Ovariectomy; D010084:Oxidation-Reduction; D051381:Rats; D020218:Response Elements / Q000502:physiology; D012769:Shock / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors
chemical_list: D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; C000619709:Hsf1 protein, rat; D014157:Transcription Factors; D019328:Buthionine Sulfoximine; D004247:DNA; D005978:Glutathione