Immune activation of murine RAW264.7 macrophages by sonicated and alkalized paramylon from Euglena gracilis

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p><jats:italic>Euglena</jats:italic> is a new super health food resource that is rich in the natural polysaccharide paramylon, a linear β-1,3-glucan with various biological activities including activity on the immune system in different cell lines and animals. Despite these reports, the immune regulation mechanism of paramylon is still unclear.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>We investigate the signaling pathways paramylon impacts in immune macrophages. In RAW264.7 macrophages, sonicated and alkalized paramylon oligomers up-regulated inducible nitric oxide synthase (iNOS) and increased secretion of nitric oxide (NO), interleukin (IL)-6 and tumor necrosis factor (TNF)-α, in a concentration-dependent manner. In addition, paramylon activated the nuclear factor-κB(NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways and inhibiting these pathways attenuated the paramylon-induced secretion of the above immune-mediators.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>These results demonstrate that <jats:italic>Euglena gracilis</jats:italic> paramylon modulates the immune system via activation of the NF-κB and MAPK signaling pathways and thus has potential therapeutic benefits.</jats:p> </jats:sec>