Induction of murine interleukin-1 beta expression by water-soluble components from Hericium erinaceum

Aim： To investigate the inductive effect of water extract from Hericiurn erinaceum （WEHE） on interleukin-1β （IL-1β） expression. Methods： A murine macrophage cell-line, RAW 264.7 was stimulated with 1 to 10 mg/L WEHE and inductions of IL-1β protein and its steady state mRNA were examined using a bioassay, Western blotting, and reverse transcription-polymerase chain reaction （RT-PCR） analysis. The inductive effect of WEHE on IL- 1β gene expression was further investigated by a chloramphenicol acetyltransferase （CAT） reporter gene assay using a transient transfection with pIL-1（870 bp）-CAT where the expression of the CAT gene was regulated by a IL-1β promoter. An electrophoretic mobility shift assay （EMSA） was also performed to examine transcription factors, nuclear factor-kappa B （NF-κB）, activator protein 1 （AP- 1）, nuclear factor interleukin-6 （NF-IL6）, and cAMP response element （CRE）/activating transcription factor （ATF）. Results： WEHE induced IL-1β production in both its mRNA and protein expression in a dosedependent manner. The inductive effect of WEHE on IL- 1β gene expression was due to the augmentation of the IL- 1β transcription. Furthermore, EMSA showed that WEHE markedly increased the binding activities of NF-κB, and to a lesser extent, those of AP-1 and NF-IL6 to their cognate DNA recognition sites, whereas CRE/ATF binding remained constant, all of which are known to be involved in the regulation of IL-1β gene expression. Conclusion： WEHE induces IL-1β expression in macrophages at a transcriptional level by enhancing the activation of transcription factors, NF-κB, NF-IL6, and AP-1.