title: A delayed antioxidant response in heat-stressed cells expressing a non-DNA binding HSF1 mutant.
abstract: To assess the consequences of inactivation of heat shock factor 1 (HSF1) during aging, we analyzed the effect of HSF1 K80Q, a mutant unable to bind DNA, and of dnHSF1, a mutant lacking the activation domain, on the transcriptome of cells 6 and 24 h after heat shock. The primary response to heat shock (6 h recovery), of which 30 % was HSF1-dependent, had decayed 24 h after heat shock in control cells but was extended in HSF1 K80Q and dnHSF1 cells. Comparison with literature data showed that even the HSF1 dependent primary stress response is largely cell specific. HSF1 K80Q, but not HSF1 siRNA-treated, cells showed a delayed stress response: an increase in transcript levels of HSF1 target genes 24 h after heat stress. Knockdown of NRF2, but not of ATF4, c-Fos or FosB, inhibited this delayed stress response. EEF1D_L siRNA inhibited both the delayed and the extended primary stress responses, but had off target effects. In control cells an antioxidant response (ARE binding, HMOX1 mRNA levels) was detected 6 h after heat shock; in HSF1 K80Q cells this response was delayed to 24 h and the ARE complex had a different mobility. Inactivation of HSF1 thus affects the timing and nature of the antioxidant response and NRF2 can activate at least some HSF1 target genes in the absence of HSF1 activity.
authors: Department of Biomolecular Chemistry, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors: Sanne M M
authors: SM
authors: Hensen
authors: Lonneke
authors: L
authors: Heldens
authors: Siebe T
authors: ST
authors: van Genesen
authors: Ger J M
authors: GJ
authors: Pruijn
authors: Nicolette H
authors: NH
authors: Lubsen
mesh_terms: D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009154:Mutation; D051267:NF-E2-Related Factor 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D013312:Stress, Physiological; D013696:Temperature; D013997:Time Factors; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D004268:DNA-Binding Proteins; C000619706:HSF1 protein, human; D018840:HSP70 Heat-Shock Proteins; C490786:HSPA1A protein, human; C544598:HSPA6 protein, human; D000076249:Heat Shock Transcription Factors; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014157:Transcription Factors; D004247:DNA; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1