title: Immunomodulatory beta-glucan from Lentinus edodes activates mitogen-activated protein kinases and nuclear factor-kappaB in murine RAW 264.7 macrophages.
abstract: Lentinan, a cell wall β-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-κB p65 and triggered its nuclear translocation as determined by Western blotting. Moreover, LNT-S enhanced NF-κB-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-α ELISA kit and Griess reagent further demonstrated that no proinflammatory mediators such as TNF-α 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-α production, which are associated with activation of the NF-κB p65/p50 heterodimer complex. It is possible that LNT-S did not activate NF-κB p65/p50, and the activation of NF-κB 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-α and NO.
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan 430072, China. xuxj626@263.net
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Xu
authors.forename: Chen
authors.initials: C
authors.lastname: Pan
authors.forename: Lina
authors.initials: L
authors.lastname: Zhang
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ashida
mesh_terms: D000818:Animals; D002460:Cell Line; D007155:Immunologic Factors; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000276:immunology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D020942:Shiitake Mushrooms / Q000737:chemistry / Q000276:immunology*; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D047071:beta-Glucans / Q000276:immunology* / Q000494:pharmacology
chemical_list: D007155:Immunologic Factors; D016328:NF-kappa B; D047071:beta-Glucans; D020928:Mitogen-Activated Protein Kinases