Orostachys japonicus Inhibits Expression of the TLR4, NOD2, iNOS, and COX-2 Genes in LPS-Stimulated Human PMA-Differentiated THP-1 Cells by Inhibiting NF-κB and MAPK Activation

Abstract EN

Orostachys japonicus is traditionally used as an inflammatory agent.

In this report, we investigated the effects of O.

japonicus extract on the expression of genes encoding pathogen-recognition receptors (TLR2, TLR4, NOD1, and NOD2) and proinflammatory factors (iNOS, COX-2, and cytokines) in LPS-stimulated PMA-differentiated THP-1 cells and the NF-κB and MAPK pathways.

O.

japonicus induced toxicity at high concentrations but had no effect at concentrations lower than 25 μg/mL.

O.

japonicus inhibited LPS-induced TLR4 and NOD2 mRNA levels, suppressed LPS-induced iNOS and COX-2 transcription and translocation, and downregulated LPS-induced proinflammatory cytokine (IL-1β, IL-6, IL-8, and TNF-α) mRNA levels.

In addition, O.

japonicus inhibited LPS-induced NF-κB activation and IκBα degradation and suppressed LPS-induced JNK, p38 MAPK, and ERK phosphorylation.

Overall, our results demonstrate that the anti-inflammatory effects of O.

japonicus are mediated by suppression of NF-κB and MAPK signaling, resulting in reduced TLR4, NOD2, iNOS, and COX-2 expression and inhibition of inflammatory cytokine expression.