Pinocembrin inhibits lipopolysaccharide-induced inflammatory mediators production in BV2 microglial cells through suppression of PI3K/Akt/NF-κB pathway.

Pinocembrin, one of the primary flavonoids from Pinus heartwood and Eucalyptus, has been reported to have anti-inflammatory and antioxidant activity. This study was designed to evaluate the inhibitory effects of pinocembrin on inflammatory mediators production in LPS-stimulated BV2 microglial cells. The results showed that pinocembrin dose-dependently inhibited LPS-induced inflammatory mediators TNF-α, IL-1β, NO and PGE2 production. Pinocembrin also inhibited LPS-induced iNOS and COX-2 expression. Moreover, pinocembrin inhibited LPS-induced PI3K, Akt phosphorylation, and NF-κB activation, which were required for inflammatory mediators production. Furthermore, treatment of pinocembrin induced nuclear translocation of Nrf2 and expression of HO-1. In conclusion, our data indicated that pinocembrin inhibited LPS-induced inflammatory mediators production by suppressing PI3K/Akt/NF-κB signaling pathway.

Zhou LT ，Wang KJ ，Li L ，Li H ，Geng M ... -  《-》

Isobutyrylshikonin inhibits lipopolysaccharide-induced nitric oxide and prostaglandin E2 production in BV2 microglial cells by suppressing the PI3K/Akt-mediated nuclear transcription factor-κB pathway.

Microglia are important macrophages to defend against pathogens in the central nervous system (CNS); however, persistent or acute inflammation of microglia lead to CNS disorders via neuronal cell death. Therefore, we theorized that a good strategy for the treatment of CNS disorders would be to target inflammatory mediators from microglia in disease. Consequently, we investigated whether isobutyrylshikonin (IBS) attenuates the production of proinflammatory mediators, such as nitric oxide (NO) and prostaglandin E2, in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. Treatment with IBS inhibited the secretion of NO and prostaglandin E2 (as well as the expression of their key regulatory genes), inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2). Isobutyrylshikonin also suppressed LPS-induced DNA-binding activity of nuclear transcription factor-κB (NF-κB), by inhibiting the nuclear translocation of p50 and p65 in addition to blocking the phosphorylation and degradation of IκBα. Pretreatment with pyrrolidine dithiocarbamate, a specific NF-κB inhibitor, showed the down-regulation of LPS-induced iNOS and COX-2 messenger RNA by suppressing NF-κB activity. This indirectly suggests that IBS-mediated NF-κB inhibition is the main signaling pathway involved in the inhibition of iNOS and COX-2 expression. In addition, IBS attenuated LPS-induced phosphorylation of PI3K and Akt, which are upstream molecules of NF-κB, in LPS-stimulated BV2 microglial cells. The functional aspects of the PI3K/Akt signaling pathway were analyzed with LY294002, which is a specific PI3K/Akt inhibitor that attenuated LPS-induced iNOS and COX-2 expression by suppressing NF-κB activity. These data suggest that an IBS-mediated anti-inflammatory effect may be involved in suppressing the PI3K/Akt-mediated NF-κB signaling pathway.

Jayasooriya RG ，Lee KT ，Kang CH ，Dilshara MG ，Lee HJ ，Choi YH ，Choi IW ，Kim GY ... -  《-》

Downregulation of NO and PGE2 in LPS-stimulated BV2 microglial cells by trans-isoferulic acid via suppression of PI3K/Akt-dependent NF-κB and activation of Nrf2-mediated HO-1.

Little is known about whether trans-isoferulic acid (TIA) regulates the production of lipopolysaccharide (LPS)-induced proinflammatory mediators. Therefore, we examined the effect of TIA isolated from Clematis mandshurica on LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in BV2 microglial cells. We found that TIA inhibited the production of LPS-induced NO and PGE2 without accompanying cytotoxicity in BV2 microglial cells. TIA also downregulated the expression levels of specific regulatory genes such as inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) by suppressing LPS-induced NF-κB activity via dephosphorylation of PI3K/Akt. In addition, we demonstrated that a specific NF-κB inhibitor PDTC and a selective PI3K/Akt inhibitor, LY294002 effectively attenuated the expression of LPS-stimulated iNOS and COX-2 mRNA, while LY294002 suppressed LPS-induced NF-κB activity, suggesting that TIA attenuates the expression of these proinflammatory genes by suppressing PI3K/Akt-mediated NF-κB activity. Our results showed that TIA suppressed NO and PGE2 production through the induction of nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent heme oxygenase-1 (HO-1). Taken together, our data indicate that TIA suppresses the production of proinflammatory mediators such as NO and PGE2, as well as their regulatory genes, in LPS-stimulated BV2 microglial cells, by inhibiting PI3K/Akt-dependent NF-κB activity and enhancing Nrf2-mediated HO-1 expression.

Dilshara MG ，Lee KT ，Jayasooriya RG ，Kang CH ，Park SR ，Choi YH ，Choi IW ，Hyun JW ，Chang WY ，Kim YS ，Lee HJ ，Kim GY ... -  《-》

Antagonistic effects of acetylshikonin on LPS-induced NO and PGE2 production in BV2 microglial cells via inhibition of ROS/PI3K/Akt-mediated NF-κB signaling and activation of Nrf2-dependent HO-1.

Jayasooriya RG ，Lee KT ，Choi YH ，Moon SK ，Kim WJ ，Kim GY ... -  《-》

New compound, 5-O-isoferuloyl-2-deoxy-D-ribono-γ-lacton from Clematis mandshurica: Anti-inflammatory effects in lipopolysaccharide-stimulated BV2 microglial cells.

Microglia are main immune cells to exacerbate neural disorders in persistent overactivating. Therefore, it is a good strategy to regulate microglia for the treatment of neural disorders. In the present study, we isolated and characterized a novel compound, 5-O-isoferuloyl-2-deoxy-D-ribono-γ-lacton (5-DRL) from Clematis mandshurica, and evaluated its anti-inflammatory effect in lipopolysaccharide (LPS)-treated BV2 microglial cells. 5-DRL inhibited the expression of LPS-stimulated proinflammatory mediators such as nitric oxide (NO) and prostaglandin E2 (PGE2), as well as their regulatory genes inducible NO syntheses (iNOS) and cyclooxygenase-2 (COX-2). 5-DRL also downregulated the LPS-induced DNA-binding activity of nuclear factor-κB (NF-κB) through suppression of the nuclear translocation of the NF-κB subunits, p65 and p50. Consistent with the inhibition of iNOS and COX-2 via NF-κB activity with 5-DRL, an inhibitor of NF-κB, pyrrolidine dithiocarbamate (PDTC), also led to the suppression of LPS-induced iNOS and COX-2 expression. Additionally, 5-DRL corresponding with antioxidants, N-acetylcysteine (NAC) and glutathione (GSH), remarkably inhibited reactive oxygen species (ROS) generation. Both NAC and GSH, thus attenuated the expression of iNOS and COX-2 by suppressing NF-κB activation, indicating that 5-DRL suppresses LPS-induced iNOS and COX-2 expression through downregulation of the ROS-dependent NF-κB signaling pathway. The present study also indicated that 5-DRL suppresses NO and PGE2 production by inducing heme oxygenase-1 (HO-1) via nuclear factor erythroid 2-related factor 2 (Nrf2). Taken together, the present data indicate that 5-DRL attenuates the production of proinflammatory mediators such as NO and PGE2 as well as their regulatory genes in LPS-stimulated BV2 microglial cells by inhibiting ROS-dependent NF-κB activation and stimulating the Nrf2/HO-1 signal pathway. These data may be implicated in the application of 5-DRL in LPS-stimulated inflammatory disease.

Dilshara MG ，Lee KT ，Lee CM ，Choi YH ，Lee HJ ，Choi IW ，Kim GY ... -  《-》