Dioscoreanone suppresses LPS‐induced nitric oxide production and inflammatory cytokine expression in RAW 264.7 macrophages by NF‐κB and ERK1/2 signaling transduction

Caffeic acid methyl ester inhibits mast cell activation through the suppresion of MAPKs and NF-κB signaling in RBL-2H3 cells

Anti-inflammatory effects of caffeic acid derivatives have been widely reported. However, the effect of caffeic acid methyl ester (CAME) on the anti-allergic effect in mast cells has not been elucidated. The present study was aimed to investigate the anti-allergic properties of CAME and its underlying mechanism. Rat basophilic leukemia (RBL-2H3) cells were incubated withphorbol-12-myristate-13-acetate (PMA) and a calcium ionophore, A23187 to induce mast cell activation. Anti-allergic effect of CAME was examined by measuring cytokine, histamine and β-hexosaminidase release. Western blotting was conducted to determine cyclooxygenase-2 (COX-2) expression, Mitogen-activated protein kinases (MAPKs) activation and nuclear factor-κB (NF-κB) translocation. CAME significantly suppressed PMA/A23187-induced TNF-α secretion, and β-hexosaminidase and histamine release in a concentration-dependent manner. Furthermore, CAME significantly attenuated PMA/A23187-induced COX-2 expression and nuclear translocation of NF-κB. CAME significantly suppressed PMA/A23187-induced increased phosphorylation of p38, ERK and JNK RBL-2H3 cells. The results demonstrate that CAME significantly attenuates anti-allergic action by suppressing degranulation of mast cells through the suppression of MAPKs/NF-κB signaling pathway in RBL-2H3 cells.

Quercetin-Rich Ethanolic Extract of Polygonum odoratum var Pakphai Leaves Decreased Gene Expression and Secretion of Pro-Inflammatory Mediators in Lipopolysaccharide-Induced Murine RAW264.7 Macrophages

Polygonum odoratum var. Pakphai has been used in traditional Thai medicine for the treatment of flatulence and constipation and to relieve the inflammation caused by insect bites. Quercetin (Q), which is abundant in plant-based foods, has been found to exert anti-inflammatory properties. This study evaluated the anti-inflammatory activity of P. odoratum ethanolic extract in RAW264.7 macrophage cells. Leaves were extracted with 50% ethanol, phenolics and flavonoids were then analyzed using UHPLC-QTOF-MS and HPLC-DAD. RAW264.7 cells were induced with lipopolysaccharides (LPSs). They were then treated with the extract and prostaglandin E2 (PGE2), and interleukin-6 (IL-6) and tumor necrotic factor-alpha (TNF-α) concentrations were determined. Levels of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), IL-6 and TNF-α mRNAs were analyzed using qRT-PCR. Chemical analysis demonstrated that the extract was abundant with Q while also containing catechin, gallic acid, epicatechin gallate and coumarin. The extract increased the viability of RAW264.7 cells and dose-dependently decreased nitric oxide production, PGE2, IL-6 and TNF-α levels in the medium from the LPS-induced RAW264.7 cell culture. Consistently, COX-2, iNOS, IL-6 and TNF-α mRNA levels were decreased in a concentration-dependent manner (p < 0.05). Thus, the quercetin-rich ethanolic extract derived from P. odoratum var Pakphai leaves can exert anti-inflammatory activity in LPS-induced RAW264.7 cells through a reduction of the pro-inflammatory mediator response.

DRM02, a novel phosphodiesterase-4 inhibitor with cutaneous anti-inflammatory activity

Chronic inflammatory skin disorders are frequently associated with impaired skin barrier function. Selective phosphodiesterase-4 (PDE4) inhibition constitutes an effective therapeutic strategy for the treatment of inflammatory skin diseases. We now report the pharmacological anti-inflammatory profile of DRM02, a novel pyrazolylbenzothiazole derivative with selective in vitro inhibitory activity toward PDE4 isoforms A, B and D. DRM02 treatment of cultured primary human and mouse epidermal keratinocytes interfered with pro-inflammatory cytokine production elicited by interleukin-1α and tumor necrosis factor-α. Similarly, DRM02 inhibited the production of pro-inflammatory cytokines by human peripheral blood mononuclear cells ex vivo and cultured THP-1 monocyte-like cells, with IC₅₀ values of 0.6-14 µM. These anti-inflammatory properties of DRM02 were associated with dose-dependent repression of nuclear factor-κB (NF-κB) transcriptional activity. In skin inflammation in vivo mouse models, topically applied DRM02 inhibited the acute response to phorbol ester and induced Th2-type contact hypersensitivity reactivity. Further, DRM02 also decreased cutaneous clinical changes and expression of Th17 immune pathway cytokines in a mouse model of psoriasis evoked by repeated topical imiquimod application. Thus, the overall pharmacological profiling of the PDE4 inhibitor DRM02 has revealed its potential as a topical therapy for inflammatory skin disorders and restoration of skin homeostasis.

3,4,5-Trihydroxycinnamic Acid Inhibits LPS-Induced Inflammatory Response by Increasing SIRT1 Expression in Human Umbilical Vein Endothelial Cells

3,4,5-Trihydroxycinnamic acid (THC) has been demonstrated to exert anti-inflammatory activities in LPS-induced RAW264.7 murine macrophage cells and in LPS-induced septic mice. However, the effect of THC on the inflammatory response in vascular endothelial cells has not been clearly examined. The goal of the present study was to elucidate the anti-inflammatory properties of THC and its underlying mechanism in LPS-challenged human umbilical vein endothelial cells (HUVECs). THC significantly suppressed LPS-induced interleukin-1β production and intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression and significantly decreased LPS-induced nuclear factor-κB activation by attenuating p65 phosphorylation and inhibitor of kappa B degradation. To understand the underlying mechanism of the anti-inflammatory effect of THC, the involvement of the sirtuin 1 (SIRT1) signaling pathway was examined. THC resulted in increased expression of SIRT1 in LPS-challenged HUVECs. Among the downstream molecular targets of SIRT1, the level of LPS-induced acetylated p53 was significantly decreased by THC treatment, whereas no noticeable change was observed in the levels of forkhead box O3 and peroxisome proliferator activated receptor gamma coactivator 1 alpha. In conclusion, the results clearly demonstrate that THC possesses anti-inflammatory properties by increasing SIRT1 expression and subsequent suppression of p53 activation in LPS-challenged HUVECs.

Isorhamnetin-3-O-Glucuronide Suppresses JNK and p38 Activation and Increases Heme-Oxygenase-1 in Lipopolysaccharide-Challenged RAW264.7 Cells

Preclinical Research Isorhanmetin (ISH) exhibits a wide range of biological properties including anticancer, anti-oxidant and anti-inflammatory activities. However, the pharmacological properties of isorhamnetin-3-O-glucuronide (IG), a glycoside derivative of ISH, have not been extensively examined. The objective of this study was to examine the anti-inflammatory properties of IG and its underlying mechanism in lipopolysaccharide (LPS)-challenged RAW264.7 macrophage cells in comparison with its aglycone, ISH. IG suppressed LPS-induced extracellular secretion of the proinflammatory mediators, nitric oxide (NO) and PGE2 , and proinflammatory protein expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2. IG also increased expression of heme oxygenase-1 (HO-1). IG attenuated LPS-induced activation of c-Jun N-terminal kinase (JNK) and p38 in a concentration-dependent manner with negligible suppression of extracellular signal-regulated kinases (ERK) phosphorylation. In conclusion, this study demonstrates that IG exerts anti-inflammatory activity by increasing HO-1 expression and by suppressing JNK and p38 signaling pathways in LPS-challenged RAW264.7 macrophage cells. Drug Dev Res 77 : 143-151, 2016. © 2016 Wiley Periodicals, Inc.

Potent Anti-inflammatory and Analgesic Actions of the Chloroform Extract of Dendropanax morbifera Mediated by the Nrf2/HO-1 Pathway

Dendropanax morbifera LEVEILLE (DP) has been used in traditional Korean medicines to treat a variety of inflammatory diseases. Although the in vitro anti-inflammatory potential of this plant is understood, its in vivo efficacy and underlying molecular mechanism of anti-inflammatory effects are largely unknown. We elucidated the anti-inflammatory and analgesic activities and the underlying molecular mechanisms of DP using in vitro and in vivo models. Lipopolysaccharide (LPS)-stimulated murine macrophages were used to analyze the in vitro anti-inflammatory potential of DP extract and to elucidate the underlying mechanisms. In vivo animal models of phorbol 12-myristate 13-acetate (TPA)-induced ear edema and acetic acid-induced writhing response tests were used to analyze the in vivo anti-inflammatory effects and anti-nociceptive effects of DP extract, respectively. Methanolic extract of DP (DPME) significantly inhibited the release of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-activated macrophages. Among the five sub-fractions, the chloroform fraction (DP-C) showed the most potent suppressive effects against pro-inflammatory mediators and cytokines in LPS-stimulated macrophages. These effects were attributed to inhibition of nuclear factor-κB (NF-κB) nuclear translocation and c-Jun N terminal kinase (JNK) 1/2 phosphorylation and to activation of NF-E2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling. DP-C exhibited strong protective in vivo effects in TPA-induced ear edema mouse model and acetic acid-induced writhing response test. Our data suggest that DP-C has potent anti-inflammatory and analgesic activities and may be a promising treatment against a variety of inflammatory diseases.

Quercetin-3-O-β-D-Glucuronide Suppresses Lipopolysaccharide-Induced JNK and ERK Phosphorylation in LPS-Challenged RAW264.7 Cells

Quercetin, a flavonol, has been reported to exhibit a wide range of biological properties including anti-oxidant and anti-inflammatory activities. However, pharmacological properties of quercetin-3-O-β-D-glucuronide (QG), a glycoside derivative of quercetin, have not been extensively examined. The objective of this study is to elucidate the anti-inflammatory property and underlying mechanism of QG in lipopolysaccharide (LPS)-challenged RAW264.7 macrophage cells in comparison with quercetin. QG significantly suppressed LPS-induced extracellular secretion of pro-inflammatory mediators such as nitric oxide (NO) and PGE₂, and pro-inflammatory protein expressions of iNOS and COX-2. To elucidate the underlying mechanism of the anti-inflammatory property of QG, involvement of MAPK signaling pathways was examined. QG significantly attenuated LPS-induced activation of JNK and ERK in concentration-dependent manners with a negligible effect on p38. In conclusion, the present study demonstrates QG exerts anti-inflammatory activity through the suppression of JNK and ERK signaling pathways in LPS-challenged RAW264.7 macrophage cells.

The effect of anti-inflammatory properties of ferritin light chain on lipopolysaccharide-induced inflammatory response in murine macrophages

Ferritin light chain (FTL) reduces the free iron concentration by forming ferritin complexes with ferritin heavy chain (FTH). Thus, FTL competes with the Fenton reaction by acting as an antioxidant. In the present study, we determined that FTL influences the lipopolysaccharide (LPS)-induced inflammatory response. FTL protein expression was regulated by LPS stimulation in RAW264.7 cells. To investigate the role of FTL in LPS-activated murine macrophages, we established stable FTL-expressing cells and used shRNA to silence FTL expression in RAW264.7 cells. Overexpression of FTL significantly decreased the LPS-induced production of tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), nitric oxide (NO) and prostaglandin E2 (PGE2). Additionally, overexpression of FTL decreased the LPS-induced increase of the intracellular labile iron pool (LIP) and reactive oxygen species (ROS). Moreover, FTL overexpression suppressed the LPS-induced activation of MAPKs and nuclear factor-κB (NF-κB). In contrast, knockdown of FTL by shRNA showed the reverse effects. Therefore, our results indicate that FTL plays an anti-inflammatory role in response to LPS in murine macrophages and may have therapeutic potential for treating inflammatory diseases.

N-(p-Coumaryol)-Tryptamine Suppresses the Activation of JNK/c-Jun Signaling Pathway in LPS-Challenged RAW264.7 Cells

N-(p-Coumaryol) tryptamine (CT), a phenolic amide, has been reported to exhibit anti-oxidant and anti-inflammatory activities. However, the underlying mechanism by which CT exerts its pharmacological properties has not been clearly demonstrated. The objective of this study is to elucidate the anti-inflammatory mechanism of CT in lipopolysaccharide (LPS)-challenged RAW264.7 macrophage cells. CT significantly inhibited LPS-induced extracellular secretion of pro-inflammatory mediators such as nitric oxide (NO) and PGE2, and protein expressions of iNOS and COX-2. In addition, CT significantly suppressed LPS-induced secretion of pro-inflammatory cytokines such as TNF-α and IL-1β. To elucidate the underlying anti-inflammatory mechanism of CT, involvement of MAPK and Akt signaling pathways was examined. CT significantly attenuated LPS-induced activation of JNK/c-Jun, but not ERK and p38, in a concentration-dependent manner. Interestingly, CT appeared to suppress LPS-induced Akt phosphorylation. However, JNK inhibition, but not Akt inhibition, resulted in the suppression of LPS-induced responses, suggesting that JNK/c-Jun signaling pathway significantly contributes to LPS-induced inflammatory responses and that LPS-induced Akt phosphorylation might be a compensatory response to a stress condition. Taken together, the present study clearly demonstrates CT exerts anti-inflammatory activity through the suppression of JNK/c-Jun signaling pathway in LPS-challenged RAW264.7 macrophage cells.

Methyl p-Hydroxycinnamate Suppresses Lipopolysaccharide-Induced Inflammatory Responses through Akt Phosphorylation in RAW264.7 Cells

Derivatives of caffeic acid have been reported to possess diverse pharmacological properties such as anti-inflammatory, anti-tumor, and neuroprotective effects. However, the biological activity of methyl p-hydroxycinnamate, an ester derivative of caffeic acid, has not been clearly demonstrated. This study aimed to elucidate the anti-inflammatory mechanism of methyl p-hydroxycinnamate in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Methyl p-hydroxycinnamate significantly inhibited LPS-induced excessive production of pro-inflammatory mediators such as nitric oxide (NO) and PGE₂ and the protein expression of iNOS and COX-2. Methyl p-hydroxycinnamate also suppressed LPS-induced overproduction of pro-inflammatory cytokines such as IL-1β and TNF-α. In addition, methyl p-hydroxycinnamate significantly suppressed LPS-induced degradation of IκB, which retains NF-κB in the cytoplasm, consequently inhibiting the transcription of pro-inflammatory genes by NF-κB in the nucleus. Methyl p-hydroxycinnamate exhibited significantly increased Akt phosphorylation in a concentration-dependent manner. Furthermore, inhibition of Akt signaling pathway with wortmaninn abolished methyl p-hydroxycinnamate-induced Akt phosphorylation. Taken together, the present study clearly demonstrates that methyl p-hydroxycinnamate exhibits anti-inflammatory activity through the activation of Akt signaling pathway in LPS-stimulated RAW264.7 macrophage cells.

Phosphorylation of Akt Mediates Anti-Inflammatory Activity of 1-p-Coumaroyl β-D-Glucoside Against Lipopolysaccharide-Induced Inflammation in RAW264.7 Cells

Hydroxycinnamic acids have been reported to possess numerous pharmacological activities such as antioxidant, anti-inflammatory, and anti-tumor properties. However, the biological activity of 1-p-coumaroyl β-D-glucoside (CG), a glucose ester derivative of p-coumaric acid, has not been clearly examined. The objective of this study is to elucidate the anti-inflammatory action of CG in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. In the present study, CG significantly suppressed LPS-induced excessive production of pro-inflammatory mediators such as nitric oxide (NO) and PGE2 and the protein expression of iNOS and COX-2. CG also inhibited LPS-induced secretion of pro-inflammatory cytokines, IL-1β and TNF-α. In addition, CG significantly suppressed LPS-induced degradation of IκB. To elucidate the underlying mechanism by which CG exerts its anti-inflammatory action, involvement of various signaling pathways were examined. CG exhibited significantly increased Akt phosphorylation in a concentration-dependent manner, although MAPKs such as Erk, JNK, and p38 appeared not to be involved. Furthermore, inhibition of Akt/PI3K signaling pathway with wortmannin significantly, albeit not completely, abolished CG-induced Akt phosphorylation and anti-inflammatory actions. Taken together, the present study demonstrates that Akt signaling pathway might play a major role in CG-mediated anti-inflammatory activity in LPS-stimulated RAW264.7 macrophage cells.

Avicularin Inhibits Lipopolysaccharide-Induced Inflammatory Response by Suppressing ERK Phosphorylation in RAW 264.7 Macrophages

suppresAvicularin, quercetin-3-α-L-arabinofuranoside, has been reported to possess diverse pharmacological properties such as anti-inflammatory and anti-infectious effects. However, the underlying mechanism by which avicularin exerts its anti-inflammatory activity has not been clearly demonstrated. This study aimed to elucidate the anti-inflammatory mechanism of avicularin in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Avicularin significantly inhibited LPS-induced excessive production of pro-inflammatory mediators such as nitric oxide (NO) and PGE₂ and the protein levels of iNOS and COX-2, which are responsible for the production of NO and PGE₂, respectively. Avicularin also suppressed LPS-induced overproduction of pro-inflammatory cytokine IL-1β. Furthermore, avicularin significantly suppressed LPS-induced degradation of IκB, which retains NF-κB in the cytoplasm, consequently inhibiting the transcription of pro-inflammatory genes by NF-κB in the nucleus. To understand the underlying signaling mechanism of anti-inflammatory activity of avicularin, involvement of multiple kinases was examined. Avicularin significantly attenuated LPS-induced activation of ERK signaling pathway in a concentration-dependent manner. Taken together, the present study clearly demonstrates that avicularin exhibits anti-inflammatory activity through the suppression of ERK signaling pathway in LPS-stimulated RAW 264.7 macrophage cells.