Eun-Yi Ko

The roles of NF-κB and ROS in regulation of pro-inflammatory mediators of inflammation induction in LPS-stimulated zebrafish embryos

Abstract In this study, the roles of reactive oxygen species (ROS) and NF‐&kgr;B on inflammation induction in lipopolysaccharide (LPS)‐stimulated zebrafish embryos were evaluated using N‐acetyl‐l‐cysteine (NAC) and pyrrolidine dithiocarbamate (PDTC), specific inhibitors of ROS and NF‐&kgr;B, respectively. LPS‐stimulated zebrafish embryos showed increasing production of NO and ROS and expression of iNOS and COX‐2 protein, compared to a control group without LPS. However, NAC significantly inhibited production of NO and ROS and markedly suppressed expression of iNOS and COX‐2 protein in LPS‐stimulated zebrafish embryos. The mRNA expressions of NF‐&kgr;B such as p65NF‐&kgr;B and I&kgr;B‐A were significantly increased after LPS stimulation, whereas PDTC attenuated mRNA expression of NF‐&kgr;B. PDTC also inhibited production of NO and reduced expression of iNOS and COX‐2 protein in LPS‐stimulated zebrafish embryos. Taken together, these results indicated that LPS increases pro‐inflammatory mediators in zebrafish embryos through ROS and NF‐&kgr;B regulation. HighlightsWe confirmed the roles of ROS and NF‐&kgr;B in LPS‐stimulated zebrafish embryos.We employed NAC and PDTC, which are specific inhibitors of ROS and NF‐kB.NAC inhibited LPS‐induced NO and ROS production and iNOS and COX‐2 expression.PDTC also inhibited LPS‐induced NO production and iNOS and COX‐2 expression.PDTC significantly inhibited LPS‐induced increases in the mRNA expression of NF‐&kgr;B.

Anti-inflammatory effects of trans-1,3-diphenyl-2,3-epoxypropane-1-one in zebrafish embryos in vivo model.

In this study, trans-1,3-diphenyl-2,3-epoxypropane-1-one (DPEP) was evaluated for its anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated zebrafish embryos. In the present study, DPEP exhibited potential protective effect in the zebrafish embryos as confirmed by survival rate. DPEP acts as an effective agent against reactive oxygen species (ROS) formation induced by LPS. Moreover, DPEP effectively inhibited LPS-induced nitric oxide (NO) production in zebrafish embryos. In addition, DPEP significantly reduced the expression of inducible NOS (iNOS) and cycloxygenase 2 (COX-2), which generate NO as a key mediator of inflammation in a concentration-dependent manner. According to these results, DPEP could be considered an effective anti-inflammatory agent, which might be further developed as a functional ingredient. This is the first report of the anti-inflammatory activity of DPEP in the LPS-stimulated zebrafish model.

2,4,6-Trihydroxybenzaldehyde, a potential anti-obesity treatment, suppressed adipocyte differentiation in 3T3-L1 cells and fat accumulation induced by high-fat diet in C57BL/6 mice.

In the present study, 2,4,6-trihydroxybenzaldehyde (THB) was evaluated for inhibitory effects on adipocyte differentiation in 3T3-L1 cells and anti-obesity effects in mice with high-fat diet (HFD)-induced obesity. Lipid accumulation measurement indicated that THB markedly inhibited adipogenesis, and this involved down-regulation of the expression of the adipogenesis-related proteins, CCAAT/enhancer-binding protein α (C/EBPα), peroxisome proliferator-activated receptor γ (PPARγ), fatty acid synthase (FAS) and sterol regulatory element-binding protein-1c (SREBP-1c), in 3T3-L1 pre-adipocyte cells. In a mouse model of HFD-induced obesity, oral administration of THB (5 and 25mg/kg for 13 weeks) reduced the HFD-induced increase in weight gain. THB administration also reduced serum levels of glucose, triglycerides, and total cholesterol. A reduction in the hypertrophy of white adipose tissue was also observed. Furthermore, THB administration inhibited HFD-induced hepatic steatosis. These results provided evidence that administration of THB alleviated HFD-induced obesity in C57BL/6 mice and revealed the potential of THB as a nutraceutical to help prevent or treat obesity and the associated metabolic disorders.

Anti-inflammatory effect of supercritical extract and its constituents from Ishige okamurae

The anti-inflammatory properties of the supercritical fluid extract of Ishige okamurae (SFEIO) on lipopolysaccharide (LPS)-stimulated murine RAW 264.7 macrophages. The lipid profile of the SFEIO, reviled the presence of palmitic acid (220.2 mg/g), linoleic acid (168.0 mg/g), and oleic acid (123.0 mg/g). SFEIO was found to exert its anti-inflammatory effects through inhibiting nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 production in LPS-stimulated RAW 264.7 cells, without inducing cytotoxicity. SFEIO did not effect on the LPS-induced p38 kinase phosphorylation, whereas it attenuated the extracellular-related signaling kinase (ERK) and c-Jun N-terminal kinase (JNK) phosphorylation. Furthermore, SFEIO inhibited the LPS-induced IκB-α degradation and p50 NF-κB activation. These results suggest that SFEIO exerts its anti-inflammatory effects in LPS-activated RAW 264.7 cells by down-regulating the activation of ERK, JNK, and NF-κB.

Anti-inflammatory effect and mechanism of action of Lindera erythrocarpa essential oil in lipopolysaccharide-stimulated RAW264.7 cells

The aim of this study was to investigate the chemical constituents of Lindera erythrocarpa essential oil (LEO) by gas chromatography-mass spectrometry and evaluate their inhibitory effect on the expression of pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Fifteen compounds, accounting for 63.7 % of the composition of LEO, were identified. The main compounds were nerolidol (18.73 %), caryophyllene (14.41 %), α-humulene (7.73 %), germacrene-D (4.82 %), and α-pinene (4.47 %). LEO significantly inhibited the expression of inducible nitric oxide (NO) synthase and cyclooxygenase-2, and subsequent production of NO and prostaglandin E2. In addition, it reduced the release of pro-inflammatory cytokines in LPS-activated RAW264.7 cells. The molecular mechanism underlying the effect of LEO was associated with inhibition of the phosphorylation of mitogen-activated protein kinase (MAPK). Furthermore, LEO inhibited LPS-induced phosphorylation and degradation of inhibitor of kappa B-α, which is required for the activation of the p50 and p65 nuclear factor (NF)-κB subunits in RAW264.7 cells. Taken together, these data suggest that LEO exerted its anti-inflammatory effect by downregulating LPS-induced production of pro-inflammatory mediators through the inhibition of NF-κB and MAPK signaling in RAW264.7 cells.

6-7-Dimethoxy-4-methylcoumarin suppresses pro-inflammatory mediator expression through inactivation of the NF-κB and MAPK pathways in LPS-induced RAW 264.7 cells.

In this study, we investigated the ability of 6,7-dimethoxy-4-methylcoumarin (DMC) to inhibit lipopolysaccharide (LPS)-induced expression of pro-inflammatory mediators in mouse macrophage (RAW 264.7) cells, and the molecular mechanism through which this inhibition occurred. Our results indicated that DMC downregulated LPS-induced nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, thereby reducing the production of NO and prostaglandin E2 (PGE2) in LPS-activated RAW 264.7 cells. Furthermore, DMC suppressed LPS-induced production of pro-inflammatory cytokines such as interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α. To elucidate the mechanism underlying the anti-inflammatory activity of DMC, we assessed its effects on the mitogen-activated protein kinase (MAPK) pathway and the activity and expression of nuclear transcription factor kappa-B (NF-κB). The experiments demonstrated that DMC inhibited LPS-induced phosphorylation of extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinase (JNK), and p38. In addition, it attenuated LPS-induced NF-κB activation via the inhibition of IκB-α phosphorylation. Taken together, these data suggest that DMC exerts its anti-inflammatory effects in RAW 264.7 cells through the inhibition of LPS-stimulated NF-κB and MAPK signaling, thereby downregulating the expression of pro-inflammatory mediators.

Trans-1,3-diphenyl-2,3-epoxypropan-1-one, a chalcone derivative, induces apoptosis via ROS-mediated down-regulation of Bcl-xL in human leukemia HL-60 cells

The anticancer effects of trans-1,3-diphenyl-2,3-epoxypropan-1-one (DPEP), a chalcone derivative, were investigated in human leukemia HL-60 cells. Treatment of HL-60 cells with various concentration of DPEP resulted in a sequence of events characteristic of apoptosis, including loss of cell viability, morphological changes, and increased sub-G1 DNA content. We demonstrated that DPEP elevates reactive oxygen species (ROS) levels in HL-60 cells, and that the ROS scavenger N-acetylcysteine (NAC) could block DPEP-induced ROS generation and apoptosis. Western blot analysis revealed that DPEP inhibits Bcl-xL expression, leading to caspase-3 activation and poly-ADP-ribose polymerase (PARP) cleavage, thereby inducing apoptosis. However, NAC pre-treatment significantly inhibited the activation of caspase-3 and PARP cleavage and reduced Bcl-xL levels. These findings provide the first evidence that DPEP may inhibit the growth of HL-60 cells and induce apoptosis through a ROS-mediated Bcl-xL pathway.