Inhibition of inducible NO synthase, cyclooxygenase-2 and interleukin-1beta by torilin is mediated by mitogen-activated protein kinases in microglial BV2 cells.
OBJECTIVE
Traditionally, the stem and root bark of Ulmus davidiana var. japonica (Ulmaceae) have been known to be anti-inflammatory in Korea. Anti-inflammatory effects of torilin, isolated from this plant and the underlying mechanisms were examined by using lipopolysaccharide (LPS)-stimulated microglial BV2 cells.


METHODS
The cells were treated with torilin prior to LPS exposure and the effects on pro-inflammatory enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and a pro-inflammatory cytokine, interleukin-1beta (IL-1beta) were analysed by RT-PCR, Western blot or elisa. To reveal the mechanism of action of torilin we investigated the involvement of mitogen-activated protein kinase (MAPK) cascades and their downstream transcription factors, nuclear factor-kappaB (NF-kappaB) and cyclic AMP-responsive element (CRE)-binding protein (CREB).


RESULTS
Torilin significantly reduced the LPS-induced expression of iNOS, COX-2 and IL-1beta, and the subsequent release of NO, prostaglandin E(2) and IL-1beta into culture medium. LPS stimulation of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 MAPK was inhibited by torilin. In addition, the inhibitory effect of torilin on NF-kappaB and CREB was shown by torilin-mediated recovery of LPS-induced degradation of inhibitor kappaB-alpha and suppression of LPS-induced phosphorylation of CREB respectively.


CONCLUSIONS
This study indicates that torilin inhibited LPS-induced iNOS, COX-2 and IL-1beta via down-regulation of ERK1/2, p38 MAPK, NF-kappaB and CREB and suggests that torilin has a potential as an anti-inflammatory drug candidate.
Choi
Y
Y
College of Pharmacy and Research Institute of Pharmaceutical Science, Seoul National University, Seoul, Korea.
Lee
M K
MK
Lim
S Y
SY
Sung
S H
SH
Kim
Y C
YC
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000037:antagonists & inhibitors / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000096:biosynthesis; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000378:metabolism; D053583:Interleukin-1beta / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000502:physiology*; D051379:Mice; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D010766:Phosphorylation; D045789:Sesquiterpenes, Guaiane / Q000494:pharmacology
D000894:Anti-Inflammatory Agents, Non-Steroidal; C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D052246:Cyclooxygenase 2 Inhibitors; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D016328:NF-kappa B; D045789:Sesquiterpenes, Guaiane; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2; D015232:Dinoprostone; C112694:torilin