HSF1 regulates expression of G-CSF through the binding element for NF-IL6/CCAAT enhancer binding protein beta

Abstract

Heat shock factor 1 (HSF1) is the major heat shock transcription factor and plays an essential role in mediating the cellular response to physiological and environmental stress. We found that LPS-induced expression of the granulocyte-colony stimulating factor (G-CSF) gene was upregulated in HSF1 knock-out (HSF1(-/-)) mice using a gene array. In order to determine whether and how HSF1 regulates the induced expression of G-CSF, mRNA, and protein levels of G-CSF were detected by Northern blotting and ELISA, the promoter of G-CSF was analyzed with an online transcription element search system and the transcriptional activity of the G-CSF promoter was analyzed by EMSA and a reporter gene assay. The results showed that transcription and protein secretion of G-CSF induced by LPS are both inhibited by HSF1. Three high affinity binding sites for NF-IL6/CCAAT enhancer binding protein beta, but no heat shock element, were identified in the core promoter of G-CSF. The DNA-binding capability of NF-IL6 to the G-CSF promoter was reinforced by LPS but not influenced by heat shock or HSF1. However, HSF1 was observed to bind to the binding sites of NF-IL6 in the G-CSF promoter. The transcriptional activity of the G-CSF promoter was enhanced by LPS or NF-IL6 and inhibited by HSF1 in a dose dependent manner. We conclude that HSF1 regulates expression of G-CSF through binding to the NF-IL6-binding element.

HSF1 Is a Transcriptional Activator of IL-10 Gene Expression in RAW264.7 Macrophages

“…Our recent report also demonstrated that HSF1 attenuates transcription of the G-CSF promoter activated by C/ EBPβ through its binding to the C/EBPβ binding element [9]. When we co-transfected C/EBPβ and HSF1 into RAW264.7 cells, the promoter activity of pIL10 (−1,562) was comparable with that of C/EBPβ or HSF1 overexpression alone.…”

“…The suppression of TNF-α requires binding of HSF1 to a high affinity HSE in the 5′-untranslated region of TNF-α gene [7], whereas the repression of IL-1β requires direct interaction of HSF1 with C/EBPβ ( also known as NF-IL6), a critical regulator in IL-1β gene transcription, and the binding of HSF1 to IL-1β gene promoter [8]. A recent report in our laboratory showed that the transcription and secretion of G-CSF induced by LPS were inhibited by HSF1, and HSF1 downregulated the transcription through binding to the C/EBPβ binding element [9]. In addition to production of pro-inflammatory cytokines, LPS also stimulates macrophages to produce anti-inflammatory mediators such as IL-10 and IL-1RA.…”

Heat shock protein 70 down-regulates the production of toll-like receptor-induced pro-inflammatory cytokines by a heat shock factor-1/constitutive heat shock element-binding factor-dependent mechanism

“…Other studies report that HSF-1 deficient mice have increased levels of TNF-α after stimulation with LPS [59], and that Escherichia coli -induced inflammation is resolved faster when a heat shock precedes inoculation with bacteria [60]. HSF-1 also inhibits the transcription and secretion of G-CSF in response to LPS [61]. Furthermore, HSF-1 has been reported to prevent the overproduction of pro-inflammatory cytokines in conditions such as sepsis [62], potentially decreasing the inflammation-associated damage.…”

HSF1 functions as a transcription regulator for Dp71 expression

“…The extract preparation and binding reaction were performed as previously described (Zhang et al 2011). DNA probes were generated according to the HSE sites at positions −840 to −817 bp of the mouse Dp71 promoter as double-stranded, HRP-labeled oligonucleotides corresponding to the wildtype sequences (5′-actgttagTTCTAGAAggacattt -3′) and mutant sequence (5′-actgttagCAGTATGGggacattt -3′).…”