Src kinase-targeted anti-inflammatory activity of davallialactone from Inonotus xeranticus in lipopolysaccharide-activated RAW264.7 cells.
OBJECTIVE
Mushrooms are popular both as food and as a source of natural compounds of biopharmaceutical interest. Some mushroom-derived compounds such as beta-glucan have been shown to be immunostimulatory; this study explores the anti-inflammatory properties of hispidin analogues derived from the mushroom, Inonotus xeranticus. We sought to identify the molecular mechanism of action of these hispidin analogues by determining their effects on lipopolysaccharide (LPS)-mediated inflammatory responses in a macrophage cell line.


METHODS
The production of inflammatory mediators was determined by Griess assay, reverse transcription-PCR and ELISA. The inhibitory effect of davalliactone on LPS-induced activation of signalling cascades was assessed by western blotting, immunoprecipitation and direct kinase assay.


RESULTS
In activated RAW264.7 cells, davallialactone strongly downregulated LPS-mediated inflammatory responses, including NO production, prostaglandin E2 release, expression of proinflammatory cytokine genes and cell surface expression of co-stimulatory molecules. Davallialactone treatment did not alter cell viability or morphology. Davallialactone was found to exert its anti-inflammatory effects by inhibiting a signalling cascade that activates nuclear factor kappa B via PI3K, Akt and IKK, but not mitogen-activated protein kinases. Treatment with davallialactone affected the phosphorylation of these signalling proteins, but not their level of expression. These inhibitory effects were not due to the interruption of toll-like receptor 4 binding to CD14. In particular, davallialactone strongly inhibited the LPS-induced phosphorylation and kinase activity of Src, implying that Src may be a potential pharmacological target of davallialactone.


CONCLUSIONS
Our data suggest that davallialactone, a small molecule found in edible mushrooms, has anti-inflammatory activity. Davallialactone can be developed as a pharmaceutically valuable anti-Src kinase agent.
Lee
Y G
YG
School of Bioscience and Biotechnology, and Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Korea.
Lee
W M
WM
Kim
J Y
JY
Lee
J Y
JY
Lee
I-K
IK
Yun
B-S
BS
Rhee
M H
MH
Cho
J Y
JY
D000363:Agaricales / Q000737:chemistry; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000187:drug effects; D016503:Drug Delivery Systems; D007249:Inflammation / Q000188:drug therapy* / Q000503:physiopathology; D007783:Lactones / Q000302:isolation & purification / Q000494:pharmacology*; D008070:Lipopolysaccharides; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D051192:Receptors, Pattern Recognition / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D019061:src-Family Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D007783:Lactones; D008070:Lipopolysaccharides; D051192:Receptors, Pattern Recognition; C068766:davallialactone; D019061:src-Family Kinases