Phellinus linteus inhibits inflammatory mediators by suppressing redox-based NF-kappaB and MAPKs activation in lipopolysaccharide-induced RAW 264.7 macrophage.
The mushroom Phellinus linteus has been known to exhibit potent biological activity. In contrast to the immuno-potentiating properties of Phellinus linteus, the anti-inflammatory properties of Phellinus linteus have rarely been investigated. Recently, ethanol extract and n-BuOH fractions from Phellinus linteus were deemed most effective in anti-inflammatory activity in RAW 264.7 macrophages. The regulatory mechanisms of Phellinus linteus butanol fractions (PLBF) on the pharmacological and biochemical actions of macrophages involved in inflammation have not been clearly defined yet. In the present study, we tested the role of PLBF on anti-inflammation patterns in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. To investigate the mechanism by which PLBF inhibits NO and PGE2 production as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, we examined the activation of IkappaB and MAPKs in LPS-activated macrophages. PLBF clearly inhibited nuclear translocation of NF-kappaB p65 subunits, which correlated with PLBF's inhibitory effects on IkappaBalpha phosphorylation and degradation. PLBF also suppressed the activation of mitogen-activated protein (MAP) kinases including p38 and stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK). Furthermore, macrophages stimulated with LPS generated ROS via activation of membrane-bound NADPH oxidase, and ROS played an important role in the activation of nuclear factor-kappaB (NF-kappaB) and MAPKs. We demonstrated that PLBF directly blocked intracellular accumulation of reactive oxygen species in RAW 264.7 cells stimulated with LPS much as the NADPH oxidase inhibitors, diphenylene iodonium, and antioxidant pyrrolidine dithiocarbamate did. The suppression of NADPH oxidase also inhibited NO production and iNOS protein expression. Cumulatively, these results suggest that PLBF inhibits the production of NO and PGE2 through the down-regulation of iNOS and COX-2 gene expression via ROS-based NF-kappaB and MAPKs activation. Thus, PLBF may provide a potential therapeutic approach for inflammation-associated disorders.
Kim
Ho Gyoung
HG
Department of Biochemistry and Research Institute of Life Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea.
Yoon
Deok Hyo
DH
Lee
Won Ho
WH
Han
Sang Kuk
SK
Shrestha
Bhushan
B
Kim
Chun Hoi
CH
Lim
Mi Hee
MH
Chang
Woochul
W
Lim
Soyeon
S
Choi
Sunga
S
Song
Won O
WO
Sung
Jae Mo
JM
Hwang
Ki Chul
KC
Kim
Tae Woong
TW
D021581:Active Transport, Cell Nucleus; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001487:Basidiomycota / Q000737:chemistry*; D002460:Cell Line; D015232:Dinoprostone / Q000096:biosynthesis; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors*; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D010084:Oxidation-Reduction; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D020928:Mitogen-Activated Protein Kinases; D015232:Dinoprostone