N-acetylated chitooligosaccharides inhibit TNF-α-induced E-selectin expression in endothelial cells via the JNK-NF-κB pathways

The anti-inflammatory properties of highly N-acetylated chitooligosaccharides (NACOS) were explored for their potential medical applications. To analyze the effects of NACOS on tumor necrosis factor-α (TNF-α)-induced E-selectin expression, human umbilical vein endothelial cells (ECs) were pre-treated with NACOS with varied concentrations (50, 200, 500 μg/mL) for 1 day before activation by TNF-α for 4 hours. The phosphorylation of different mitogen-activated protein kinases (MAPKs) were examined by Western blot analysis. The effects of NACOS on the E-selectin promoter activity induced by TNF-α were examined by luciferase assay. The chromatin immunoprecipitation (ChIP) assay was performed to investigate the in vivo regulation of nuclear factor-κB (NF-κB) binding to the promoter regions of E-selectin in these ECs by using antibodies against p65 subunit of NF-κB and the promoter-specific primers. Overall, results show that NACOS inhibits TNF-α-induced E-selectin expression in ECs and that this inhibitory effect is mediated through the JNK/NF-κB signaling pathways.