Immunomodulatory β-Glucan from Lentinus edodes Activates Mitogen-activated Protein Kinases and Nuclear Factor-κB in Murine RAW 264.7 Macrophages

Abstract

Lentinan, a cell wall ␤-glucan from the fruiting bodies of Lentinus edodes, is well known to be a biological defense modifier, but the signal transduction pathway(s) induced by Lentinan have not been elucidated. In this study, we extracted Lentinan (LNT-S) by ultrasonication from Lentinus edodes and report that, in murine RAW 264.7 macrophages, LNT-S glucan activated NF-B p65 and triggered its nuclear translocation as determined by Western blotting. Moreover, LNT-S enhanced NF-B-luciferase activity in the Dual-Luciferase gene system assay. Its upstream signaling molecules, MAPKs such as ERK1/2 and JNK1/2, were shown to be activated by assessing the level of phosphorylation in a time-and concentration-dependent manner, but its downstream proinflammatory enzyme, inducible NOS, was not observed. The data evaluated using a TNF-␣ ELISA kit and Griess reagent further demonstrated that no proinflammatory mediators such as TNF-␣ and NO were produced by LNT-S stimulation in RAW 264.7 cells. In contrast, LPS significantly induced inducible NOS expression and increased NO and TNF-␣ production, which are associated with activation of the NF-B p65/p50 heterodimer complex. It is possible that LNT-S did not activate NF-B p65/p50, and the activation of NF-B p65 was not sufficient to stimulate cytokine production. These data demonstrate that LNT-S glucan carries out its immunomodulating activity by activating MAPK signaling pathways without secretion of TNF-␣ and NO.

β-Glucan from Lentinus edodes Inhibits Nitric Oxide and Tumor Necrosis Factor-α Production and Phosphorylation of Mitogen-activated Protein Kinases in Lipopolysaccharide-stimulated Murine RAW 264.7 Macrophages

“…and its transactivation activity but without production of NO and TNF-␣ in RAW 264.7 macrophages, which was reported in our very recent work (38). When it co-stimulates RAW 264.7 cells with LPS, LNT-S shows completely different immunomodulatory behavior, that is, it did not augment the activation of ERK1/2 and JNK1/2 (Fig.…”

“…Sample-LNT used in this study was extracted from the fruiting bodies of Lentinus edodes according to the previously described procedures (38), which was coded as LNT-S. LNT-S was dissolved in PBS and sterilized at 121°C for 20 min before use.…”

Lentinula edodes β-glucan enriched diet induces pro- and anti-inflammatory macrophages in rabbit

“…In vivo fungal β-glucans mostly elicit anti-inflammatory, anti-oxidant and anti-tumour effects [25]. Lentinan from shiitake can regulate MAP kinases JNK1/2 and ERK1/2 and enhance the nuclear translocation of NF-κB but without NO and TNF-α production in RAW 264.7 cells [26,27]. …”

Lentinan mitigates therarubicin-induced myelosuppression by activating bone marrow-derived macrophages in an MAPK/NF-κB-dependent manner

“…The purpose of our experiments was to identify a polysaccharide with immunomodulatory activity and decreased pro-inflammatory activity to reduce the side-effects of chemotherapy. Many studies have suggested that LNT can be used as an immune modulator to activate the production of various cytokines by macrophages (10,31). In the present study, we isolated BMDMs from BM tissue to examine the mechanism of action of LNT in regulating myelosuppression after chemotherapy.…”