N-acetyl-chitooligosaccharide attenuates inflammatory responses by suppression of NF-κB signaling, MAPK and NLRP3 inflammasome in macrophages

N-acetyl-chitooligosaccharide (NACOS), prepared from the shells of shrimp and crabs, has displayed various biological activities. As prebiotics and dietary supplements, these bioactive materials can be incorporated into functional foods and beverages. This study aimed to explore the anti-inflammatory effects and associated mechanism of NACOS in macrophages. We found that NACOS reduced the levels of inflammation-related cytokines in lipopolysaccharide stimulated RAW264.7 macrophages. NACOS attenuated NF-κB activation not only through the repressed IKK phosphorylation but also the blunted nuclear translocation of NF-κB subunit p65. Additionally, NACOS inhibited the level of p-JNK. Moreover, NACOS promoted NLRP3 degradation, accompanied by the blockade of caspase-1 activation and IL-1β maturation in human THP-1 cells. This study demonstrated for the first time that NACOS has a negative effect against NLRP3 protein and NLRP3 inflammasome activation. It was suggested that the pharmacological intervention of inflammatory responses by NACOS should be a promising approach against inflammation-related clinical complications.