Echinococcus granulosus cyst fluid inhibits KDM6B-mediated demethylation of trimethylated histone H3 lysine 27 and interleukin-1ß production in macrophages.

BACKGROUND: Echinococcus granulosus can manipulate its host's immune response to ensure its own survival. However, the effect of histone modifications on the regulation of the NOD-like receptor protein 3 (NLRP3) inflammasome and downstream interleukin-1ß (IL-1ß) production in response to the parasite is not fully understood. METHODS: We evaluated IL-1ß secretion through enzyme-linked immunosorbent assay and assessed reactive oxygen species levels using the dichlorodihydrofluorescein diacetate probe. Western blotting and quantitative real-time polymerase chain reaction were performed to examine the expression of NLRP3 and IL-1ß in mouse peritoneal macrophages and Tohoku Hospital Pediatrics-1 cells, a human macrophage cell line. The presence of trimethylated histone H3 lysine 27 (H3K27me3) modification on NLRP3 and IL-1ß promoters was studied by chromatin immunoprecipitation. RESULTS: Treatment with E. granulosus cyst fluid (EgCF) considerably reduced IL-1ß secretion in mouse and human macrophages, although reactive oxygen species production increased. EgCF also suppressed the expression of NLRP3 and IL-1ß. Mechanistically, EgCF prompted the enrichment of repressive H3K27me3 modification on the promoters of both NLRP3 and IL-1ß in macrophages. Notably, the presence of EgCF led to a significant reduction in the expression of the H3K27me3 demethylase KDM6B. CONCLUSIONS: Our study revealed that EgCF inhibits KDM6B expression and H3K27me3 demethylation, resulting in the transcriptional inhibition of NLRP3 and IL-1ß. These results provide new insights into the immune evasion mechanisms of E. granulosus.

Echinococcus granulosus cyst fluid inhibits inflammatory responses through inducing histone demethylase KDM5B in macrophages.

BACKGROUND: Echinococcus granulosus cyst fluid (EgCF) weakens macrophage inflammatory responses, thereby enabling the parasite to evade the immune system. However, the role of histone modification in this process remains to be explored. METHODS: The levels of IL-6, TNF-α, IL-10, H3K4me3, and KDM5B were detected using quantitative real-time PCR, ELISA, and Western blotting. The enrichment of H3K4me3 and KDM5B at the promoter of inflammatory factors was detected by chromatin immunoprecipitation. RESULTS: Based on EgCF-stimulated macrophage models, we found that EgCF significantly inhibited mRNA expression and protein secretion of IL-6 and TNF-α and upregulated mRNA expression of IL-10 under the influence of TLR4. EgCF lowered the level of H3K4me3 and promoted the transcription and protein stability of histone demethylase KDM5B. Chromatin immunoprecipitation analysis revealed that EgCF suppressed the enrichment of H3K4me3 modification at the promoters of TNF-α and IL-6 and downregulated their expression in macrophages. Additionally, the inhibition of KDM5B activity by CPI-455 weakened the anti-inflammatory effect of EgCF. CONCLUSIONS: Our findings demonstrate a novel mechanism through which EgCF promotes KDM5B expression and inhibits the enrichment of H3K4me3 at the promoters of inflammatory cytokines to suppress the inflammatory response.

Dimerization of Acetylene to Monovinylacetylene (MVA) by Bimetallic Zr/Cu Catalyst in Nieuwland Catalytic System.

Nieuwland catalyst is a key step in the dimerization of acetylene. Various zirconium metal additives incorporating Nieuwland catalysts were prepared, and their catalytic performances were assessed in acetylene dimerization. Different characterization techniques (i.e., thermogravimetric analysis, temperature-programmed reduction, X-ray diffraction, X-ray photoelectron spectroscopy, hydrogen ion concentration measurement and transmission electron microscopy) were employed in this study. The best catalytic performance was obtained over zirconium-acetylacetonate-incorporated Nieuwland catalysts, with an acetylene conversion of 53.3% and a monovinylacetylene selectivity of 87.4%. Based on these results, the zirconium acetylacetonate additive could reduce the types of transition state complexes, and it could also change the morphology of the catalyst. In addition, the additives could significantly inhibit the occurrence of trimerization products and polymers. Hence, the conversion of acetylene, monovinylacetylene selectivity, and stability of the Nieuwland catalysts were enhanced.