Labdanolic acid methyl ester (LAME) exerts anti-inflammatory effects through inhibition of TAK-1 activation.
Labdane derivatives obtained from the diterpenoid labdanediol suppressed NO and PGE(2) production in LPS-stimulated RAW 264.7 macrophages. However, mechanisms involved in these inhibitory effects are not elucidated. In this study, we investigated the signaling pathways involved in the anti-inflammatory effects of labdanolic acid methyl ester (LAME) in peritoneal macrophages and examined its therapeutic effect in a mouse endotoxic shock model. LAME reduced the production of NO and PGE(2) in LPS-activated macrophages. This effect involved the inhibition of NOS-2 and COX-2 gene expression, acting at the transcription level. Examination of the effects of the diterpene on NF-κB signaling showed that LAME inhibits the phosphorylation of IκBα and IκBβ, preventing their degradation and the nuclear translocation of the NF-κB p65 subunit. Moreover, inhibition of MAPK signaling was also observed. A further experiment revealed that LAME inhibited the phosphorylation of transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1), an upstream signaling molecule required for IKK and mitogen-activated protein kinases (MAPKs) activation. Inflammatory cytokines such as IL-6, TNF-α and IP-10 were downregulated in the presence of this compound after stimulation with LPS. Additionally, LAME also improved survival in a mouse model of endotoxemia and reduced the circulatory levels of cytokines (IL-6, TNF-α). In conclusion, these results indicate that labdane diterpene LAME significantly attenuates the pro-inflammatory response induced by LPS both in vivo and in vitro.
Departamento de Farmacología, Facultad de Farmacia, Universidad Complutense, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
Irene
I
Cuadrado
Florencia
F
Cidre
Sandra
S
Herranz
Ana
A
Estevez-Braun
Beatriz
B
de las Heras
Sonsoles
S
Hortelano
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D015232:Dinoprostone / Q000037:antagonists & inhibitors; D004224:Diterpenes / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D009569:Nitric Oxide / Q000037:antagonists & inhibitors; D000099151:MAP Kinase Kinase Kinase 7
D000893:Anti-Inflammatory Agents; D015232:Dinoprostone; D004224:Diterpenes; D008070:Lipopolysaccharides; D020930:MAP Kinase Kinase Kinases; D016328:NF-kappa B; D009569:Nitric Oxide; D000099151:MAP Kinase Kinase Kinase 7; C570295:labdanolic acid methyl ester