Hyperthermia in the febrile range induces HSP72 expression proportional to exposure temperature but not to HSF-1 DNA-binding activity in human lung epithelial A549 cells.

Content Provider	Europe PMC
Author	Tulapurkar, Mohan E. Asiegbu, Benedict E. Singh, Ishwar S. Hasday, Jeffrey D.
Abstract	Expression of heat shock proteins (HSPs) is classically activated at temperatures above the physiologic range (≥42°C) via activation of the stress-activated transcription factor, heat shock factor-1 (HSF-1). Several studies suggest that less extreme hyperthermia, especially within the febrile range, as occurs during fever and exertional/environmental hyperthemia, can also activate HSF-1 and enhance HSP expression. We compared HSP72 protein and mRNA expression in human A549 lung epithelial cells continuously exposed to 38.5°C, 39.5°C, or 41°C or exposed to a classic heat shock (42°C for 2 h). We found that expression of HSP72 protein and mRNA increased linearly as incubation temperature was increased from 37°C to 41°C, but increased abruptly when the incubation temperature was raised to 42°C. A similar response in luciferase activity was observed using A549 cells stably transfected with an HSF-1-responsive luciferase reporter plasmid. However, activation of intranuclear HSF-1 DNA-binding activity was comparable at 38.5°C, 39.5°C, and 41°C and only modestly greater at 42°C but the mobility of HSF1 protein on a denaturing gel was altered with increasing exposure temperature and was distinctly different at 42°C. These findings indicate that the proportional changes in HSF-1-dependent HSP72 expression at febrile-range temperatures are dependent upon exposure time and temperature but not on the degree of HSF-1 DNA-binding activity. Instead, HSF-1-mediated HSP expression following hyperthermia and heat shock appears to be mediated, in addition to HSF-1 activation, by posttranslational modifications of HSF-1 protein.
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ISSN	13558145
Volume Number	14
DOI	10.1007/s12192-009-0103-3
PubMed Central reference number	PMC2728283
Issue Number	5
PubMed reference number	19221897
Journal	Cell Stress & Chaperones
e-ISSN	14661268
Language	English
Publisher	Springer Netherlands
Publisher Date	2009-02-17
Publisher Place	Dordrecht
Access Restriction	Open
Rights License	© Cell Stress Society International 2009
Subject Keyword	Hyperthermia Fever Heat shock HSF-1 HRE promoter HSP72
Content Type	Text
Resource Type	Article
Subject	Cell Biology Biochemistry