Attenuation of lipopolysaccharide-induced neuroinflammatory events in BV-2 microglial cells by Moringa oleifera leaf extract

Objective: To determine the anti-neuroinflammatory activity of Moringa oleifera leaf extract (MLE) under lipopolysaccharide stimulation of mouse murine microglia BV2 cells in vitro. Methods: The cytotoxicity effect of MLE was investigated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide assay. The inflammatory response of BV-2 cells were induced with lipopolysaccharide. The generation of nitric oxide levels was determined by using Griess assay and the level of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) was evaluated by ELISA kit. The expression of iNOS, COX-2 as well as IκB-α was carried out by immunoblot analysis. Results: MLE reduced the nitric oxide production in concentration-dependent manner, and maintained the viability of BV-2 microglial cells which indicated absence of toxicity. In addition, MLE repressed the activation of nuclear factor kappa B by arresting the deterioration of IκB-α, consequently resulted in suppression of cytokines expression such as COX-2 and iNOS. Conclusions: MLE inhibitory activities are associated with the inhibition of nuclear factor kappa B transcriptional activity in BV2 microglial cells. Thus MLE may offer a substantial treatment for neuroinflammatory diseases.

Attenuation of lipopolysaccharide-induced neuroinflammatory events in BV-2 microglial cells by Moringa oleifera leaf extract

Objective: To determine the anti-neuroinflammatory activity of Moringa oleifera leaf extract (MLE) under lipopolysaccharide stimulation of mouse murine microglia BV2 cells in vitro. Methods: The cytotoxicity effect of MLE was investigated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyl-tetrazolium bromide assay. The inflammatory response of BV-2 cells were induced with lipopolysaccharide. The generation of nitric oxide levels was determined by using Griess assay and the level of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) was evaluated by ELISA kit. The expression of iNOS, COX-2 as well as IκB-α was carried out by immunoblot analysis. Results: MLE reduced the nitric oxide production in concentration-dependent manner, and maintained the viability of BV-2 microglial cells which indicated absence of toxicity. In addition, MLE repressed the activation of nuclear factor kappa B by arresting the deterioration of IκB-α, consequently resulted in suppression of cytokines expression such as COX-2 and iNOS. Conclusions: MLE inhibitory activities are associated with the inhibition of nuclear factor kappa B transcriptional activity in BV2 microglial cells. Thus MLE may offer a substantial treatment for neuroinflammatory diseases.

Vaccinium bracteatum Thunb. Exerts Anti-Inflammatory Activity by Inhibiting NF-κB Activation in BV-2 Microglial Cells

This study was designed to evaluate the pharmacological effects of Vaccinium bracteatum Thunb. methanol extract (VBME) on microglial activation and to identify the underlying mechanisms of action of these effects. The anti-inflammatory properties of VBME were studied using lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. We measured the production of nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase (COX)-2, prostaglandin E₂ (PGE₂), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6) as inflammatory parameters. We also examined the effect of VBME on intracellular reactive oxygen species (ROS) production and the activity of nuclear factor-kappa B p65 (NF-κB p65). VBME significantly inhibited LPS-induced production of NO and PGE₂ and LPS-mediated upregulation of iNOS and COX-2 expression in a dose-dependent manner; importantly, VBME was not cytotoxic. VBME also significantly reduced the generation of the pro-inflammatory cytokines TNF-α, IL-1β, and IL-6. In addition, VBME significantly dampened intracellular ROS production and suppressed NF-κB p65 translocation by blocking IκB-α phosphorylation and degradation in LPS-stimulated BV2 cells. Our findings indicate that VBME inhibits the production of inflammatory mediators in BV-2 microglial cells by suppressing NF-κB signaling. Thus, VBME may be useful in the treatment of neurodegenerative diseases due to its ability to inhibit inflammatory mediator production in activated BV-2 microglial cells.

The Anti-Inflammatory Activity of Eucommia ulmoides Oliv. Bark. Involves NF-κB Suppression and Nrf2-Dependent HO-1 Induction in BV-2 Microglial Cells

In the present study, we investigated the anti-inflammatory properties of Eucommia ulmoides Oliv. Bark. (EUE) in lipopolysaccharide (LPS)-stimulated microglial BV-2 cells and found that EUE inhibited LPS-mediated up-regulation of pro-inflammatory response factors. In addition, EUE inhibited the elevated production of pro-inflammatory cytokines, mediators, and reactive oxygen species (ROS) in LPS-stimulated BV-2 microglial cells. Subsequent mechanistic studies revealed that EUE suppressed LPS-induced phosphorylation of mitogen-activated protein kinases (MAPKs), phosphoinositide-3-kinase (PI3K)/Akt, glycogen synthase kinase-3β (GSK-3β), and their downstream transcription factor, nuclear factor-kappa B (NF-κB). EUE also blocked the nuclear translocation of NF-κB and inhibited its binding to DNA. We next demonstrated that EUE induced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and upregulated heme oxygenase-1 (HO-1) expression. We determined that the significant up-regulation of HO-1 expression by EUE was a consequence of Nrf2 nuclear translocation; furthermore, EUE increased the DNA binding of Nrf2. In contrast, zinc protoporphyrin (ZnPP), a specific HO-1 inhibitor, blocked the ability of EUE to inhibit NO and PGE2 production, indicating the vital role of HO-1. Overall, our results indicate that EUE inhibits pro-inflammatory responses by modulating MAPKs, PI3K/Akt, and GSK-3β, consequently suppressing NF-κB activation and inducing Nrf2-dependent HO-1 activation.

3,4,5-Trihydroxycinnamic Acid Inhibits LPS-Induced iNOS Expression by Suppressing NF-kappaB Activation in BV2 Microglial Cells

Although various derivatives of caffeic acid have been reported to possess a wide variety of biological activities such as neuronal protection against excitotoxicity and anti-inflammatory property, the biological activity of 3,4,5-trihydroxycinnamic acid (THC), a derivative of hydroxycinnamic acids, has not been clearly examined. The objective of the present study is to evaluate the anti-inflammatory effects of THC on lipopolysaccharide (LPS)-stimulated BV2 microglial cells. THC significantly suppressed LPS-induced excessive production of nitric oxide (NO) and expression of iNOS, which is responsible for the production of iNOS. THC also suppressed LPS-induced overproduction of pro-inflammatory cytokines such as IL-1beta and TNF-alpha in BV2 microgilal cells. Furthermore, THC significantly suppressed LPS-induced degradation of IkappaB, which retains NF-kappaB in the cytoplasm. Therefore, THC attenuated nuclear translocation of NF-kappaB, a major pro-inflammatory transcription factor. Taken together, the present study for the first time demonstrates that THC exhibits anti-inflammatory activity through the suppression of NF-kappaB transcriptional activation in LPS-stimulated BV2 microglial cells.

Anti-inflammatory Activity of 1-docosanoyl Cafferate Isolated from Rhus verniciflua in LPS-stimulated BV2 Microglial Cells

Although various derivatives of caffeic acid have been reported to possess a wide variety of biological activities such as protection of neuronal cells against excitotoxicity, the biological activity of 1-docosanoyl cafferate (DC) has not been examined. The objective of the present study was to evaluate the anti-inflammatory effects of DC, isolated from the stem bark of Rhus verniciflua, on lipopolysaccharide (LPS)-stimulated BV2 microglial cells. Pretreatment of cells with DC significantly attenuated LPS-induced NO production, and mRNA and protein expression of iNOS in a concentration-dependent manner. DC also significantly suppressed LPS-induced release of cytokines such as TNF-alpha and IL-1beta . Consistent with the decrease in cytokine release, DC dose-dependently and significantly attenuated LPS-induced mRNA expression of these cytokines. Furthermore, DC significantly suppressed LPS-induced degradation of IKB, which retains NF-kB in the cytoplasm. Therefore, nuclear translocation of NF-kB induced by LPS stimulation was significantly suppressed with DC pretreatment. Taken together, the present study suggests that DC exerts its anti-inflammatory activity through the suppression of NF-kB translocation to the nucleus.

Comparison of Inhibitory Potency of Various Antioxidants on the Activation of BV2 Microglial Cell Lines Induced by LPS

Antioxidant properties have been proposed as a mechanism for the putative anti-inflammatory effects of phenolic compounds. To reveal the relationship between antioxidant activity and anti-inflammatory effects of various antioxidants, we measured 1, 1-diphenyl-2-picryhydrazyl (DPPH)-reducing activity and examined the inhibitory effects on LPS-induced inflammation-related gene expression in the BV2 microglial cell line. Lipopolysaccharide (LPS) (0.2microgram/ml) was used with or without antioxidants to treat cells, and the regulation of iNOS and cytokine gene expression was monitored using an RNase protection assay (RPA). Although, all tested antioxidants had similar DPPH-reducing activity and inhibited nitrite production, but the curcuminoid antioxidants (ferulic acid, caffeic acid, and curcumin) inhibited LPS-induced gene expression (iNOS, TNF-alpha, IL-1beta, IL-6, and IL-1 Ra) in a concentration-dependent manner. Other tested antioxidants did not exhibit the same effects; N-acetylcysteine (NAC) only began to suppress IL-1beta gene expression just below the concentration at which cytotoxicity occurred. Moreover, the antioxidant potency of curcuminoids appeared to have no correlation with anti-inflammatory potency. Only curcumin could inhibit LPS-induced microglial activation at a micromolar level. These data suggest that curcumin may be a safe antioxidant possessing anti-inflammatory activity.