Pei-Yin Chen

Gamma-linolenic acid inhibits inflammatory responses by regulating NF-κB and AP-1 activation in lipopolysaccharide-induced RAW 264.7 macrophages.

Gamma linolenic acid (GLA) is a member of the n-6 family of polyunsaturated fatty acids and can be synthesized from linoleic acid (LA) by the enzyme delta-6-desaturase. The therapeutic values of GLA supplementation have been documented, but the molecular mechanism behind the action of GLA in health benefits is not clear. In this study, we assessed the effect of GLA with that of LA on lipopolysaccharide (LPS)-induced inflammatory responses and further explored the molecular mechanism underlying the pharmacological properties of GLA in mouse RAW 264.7 macrophages. GLA significantly inhibited LPS-induced protein expression of inducible nitric oxide synthase, pro-interleukin-1β, and cyclooxygenase-2 as well as nitric oxide production and the intracellular glutathione level. LA was less potent than GLA in inhibiting LPS-induced inflammatory mediators. Both GLA and LA treatments dramatically inhibited LPS-induced IκB-α degradation, IκB-α phosphorylation, and nuclear p65 protein expression. Moreover, LPS-induced nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) nuclear protein–DNA binding affinity and reporter gene activity were significantly decreased by LA and GLA. Exogenous addition of GLA but not LA significantly reduced LPS-induced expression of phosphorylated extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK)-1. Our data suggest that GLA inhibits inflammatory responses through inactivation of NF-κB and AP-1 by suppressed oxidative stress and signal transduction pathway of ERK and JNK in LPS-induced RAW 264.7 macrophages.

Suppressive effects of extracts from the aerial part of Coriandrum sativum L. on LPS-induced inflammatory responses in murine RAW 264.7 macrophages.

BACKGROUND Coriandrum sativum is used not only as a spice to aid flavour and taste values in food, but also as a folk medicine in many countries. Since little is known about the anti-inflammatory ability of the aerial parts (stem and leaf) of C. sativum, the present study investigated the effect of aerial parts of C. sativum on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. We further explored the molecular mechanism underlying these pharmacological properties of C. sativum. RESULTS Ethanolic extracts from both stem and leaf of C. sativum (CSEE) significantly decreased LPS-induced nitric oxide and prostaglandin E(2) production as well as inducible nitric oxide synthase, cyclooxygenase-2, and pro-interleukin-1beta expression. Moreover, LPS-induced IkappaB-alpha phosphorylation and nuclear p65 protein expression as well as nuclear factor-kappaB (NF-kappaB) nuclear protein-DNA binding affinity and reporter gene activity were dramatically inhibited by aerial parts of CSEE. Exogenous addition of CSEE stem and leaf significantly reduced LPS-induced expression of phosphorylated mitogen-activated protein kinases (MAPKs). CONCLUSION Our data demonstrated that aerial parts of CSEE have a strong anti-inflammatory property which inhibits pro-inflammatory mediator expression by suppressing NF-kappaB activation and MAPK signal transduction pathway in LPS-induced macrophages.

Suppressive effects of Indigofera suffruticosa Mill extracts on lipopolysaccharide-induced inflammatory responses in murine RAW 264.7 macrophages.

Indigofera suffruticosa Mill is used as an herbal medicine for the treatment of inflammation. The aim of this study is to assess the anti-inflammatory potency of I. suffruticosa and its likely molecular mechanisms of action in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. Both water and ethanolic extracts of I. suffruticosa significantly decreased LPS-induced nitric oxide (NO) as well as the expression of inducible nitric oxide synthase (iNOS), tumor necrosis factor-α, and pro-interleukin-1β. Moreover, LPS-induced inhibitory factor-κB-α phosphorylation, nuclear factor-κB (NF-κB) nuclear protein-DNA binding affinity, and NF-κB reporter gene activity were dramatically inhibited by I. suffruticosa extracts. Exogenous addition of I. suffruticosa significantly induced heme oxygenase-1 (HO-1) expression, and the presence of HO-1 small interfering RNA partly reversed the inhibitory effects of I. suffruticosa on LPS-induced NO production and iNOS expression. Furthermore, I. suffruticosa induced HO-1 expression may be through activation of the ERK/nuclear factor E2-related factor 2 pathway. Eight phenolic compounds were found in the I. suffruticosa extracts, but salicylic acid was the only one detected in the plasma of mice fed with I. suffruticosa extracts. In summary, I. suffruticosa have a strong anti-inflammatory property that diminishes pro-inflammatory mediator expressions by lessening LPS-induced NF-κB activation and inducing HO-1 expression in macrophages.

18-carbon polyunsaturated fatty acids ameliorate palmitate-induced inflammation and insulin resistance in mouse C2C12 myotubes.

Skeletal muscle is a major site of insulin action. Intramuscular lipid accumulation results in inflammation, which has a strong correlation with skeletal muscle insulin resistance (IR). The aim of this study was to explore the effects of linoleic acid, alpha-linolenic acid, and gamma-linolenic acid (GLA), 18-carbon polyunsaturated fatty acids (PUFAs), on palmitic acid (PA)-induced inflammatory responses and IR in C2C12 myotubes. Our data demonstrated that these three test 18-carbon PUFAs can inhibit PA-induced interleukin-6 and tumor necrosis factor-α messenger RNA (mRNA) expression and IR as evidenced by increases in phosphorylated AKT and the 160-kD AKT substrate, mRNA and plasma membrane protein expression of glucose transporter 4, and glucose uptake. Moreover, the 18-carbon PUFAs blocked the effects of PA on activation of mitogen-activated protein kinases (MAPKs), protein kinase C-θ (PKC-θ), AMP-activated protein kinase (AMPK) and nuclear factor-κB (NF-κB). Of note, supplementation with GLA-rich borage oil decreased proinflammatory cytokine production and hindered the activation of MAPKs, PKC-θ and NF-κB in the skeletal muscles of diabetic mice. The 18-carbon PUFAs did not reverse PA-induced inflammation or IR in C2C12 myotubes transfected with a constitutively active mutant IκB kinase-β plasmid, which suggests the importance of the inhibition of NF-κB activation by the 18-carbon PUFAs. Moreover, blockade of AMPK activation by short hairpin RNA annulled the inhibitory effects of the 18-carbon PUFAs on PA-induced IR but not inflammation. Our findings suggest that the 18-carbon PUFAs may be useful in the management of PA-induced inflammation and IR in myotubes.

Antiinflammatory Activity of Gynura bicolor (紅鳳菜 Hóng Fèng Cài) Ether Extract Through Inhibits Nuclear Factor Kappa B Activation

This study investigated effects of the Gynura bicolor (Roxb. and Willd.) DC. ether extract (GBEE) on nitric oxide (NO) and prostaglandin (PG)E2 production on the lipopolysaccharide (LPS)-induced inflammatory response in RAW 264.7 cells. A composition analysis of GBEE showed that the major compounds were b-carotene, chlorophyll, and quercetin, respectively. Furthermore, NO and PGE2 levels of 120 μg/ml GBEE-treated cells were 70% and 9.8%, respectively, than those of cells treated with LPS alone. Immunoblots assays showed that the GBEE dose-dependently suppressed LPS-induced inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 protein levels. The GBEE significantly decreased cytosolic phosphorylated (p)-IκBa and nuclear p65 protein expressions. Electrophoresis mobility shift assays indicated that the GBEE effectively inhibited nuclear factor kappa B (NF-κB) activation induced by LPS. These results support a role of the GBEE in suppressing activation of NF-κB to inhibit NO and PGE2 production in the LPS-induced inflammatory response by RAW 264.7 cells.

Indigofera suffruticosa Mill extracts up-regulate the expression of the π class of glutathione S-transferase and NAD(P)H: quinone oxidoreductase 1 in rat Clone 9 liver cells.

Because induction of phase II detoxification enzyme is important for chemoprevention, we study the effects of Indigofera suffruticosa Mill, a medicinal herb, on the expression of π class of glutathione S-transferase (GSTP) and NAD(P)H: quinone oxidoreductase 1 (NQO1) in rat Clone 9 liver cells. Both water and ethanolic extracts of I. suffruticosa significantly increased the expression and enzyme activities of GSTP and NQO1. I. suffruticosa extracts up-regulated GSTP promoter activity and the binding affinity of nuclear factor erythroid 2-related factor 2 (Nrf2) with the GSTP enhancer I oligonucleotide. Moreover, I. suffruticosa extracts increased nuclear Nrf2 accumulation as well as ARE transcriptional activity. The level of phospho-ERK was augmented by I. suffruticosa extracts, and the ERK inhibitor PD98059 abolished the I. suffruticosa extract-induced ERK activation and GSTP and NQO-1 expression. Moreover, I. suffruticosa extracts, especially the ethanolic extract increased the glutathione level in mouse liver and red blood cells as well as Clone 9 liver cells. The efficacy of I. suffruticosa extracts in induction of phase II detoxification enzymes and glutathione content implies that I. suffruticosa could be considered as a potential chemopreventive agent.

Borage oil supplementation decreases lipopolysaccharide-induced inflammation and skeletal muscle wasting in mice

Because in vitro data have shown gamma-linolenic acid (GLA) to be protective in LPS-induced macrophage inflammation and myotube atrophy, we explored the therapeutic value of borage oil (BO), a GLA rich oil, in LPS-induced inflammation and muscle wasting in C57BL/6JNarl mice. Supplementation with BO was more potent than supplementation with soybean oil (SO) in decreasing LPS-induced expression of pro-inflammatory cytokines and glutathione in serum and tissues. Notably, GLA did not reverse LPS-induced inflammatory cytokine expression in C2C12 myotubes transfected with a constitutively active mutant IκB kinase-β plasmid, which suggested the importance of the inhibition of nuclear factor-κB (NF-κB) activation by GLA. Moreover, BO prevented LPS-induced skeletal muscle weight loss as well as molecule expression of ubiquitin-proteasome pathway and the autophagy-lysosomal pathway which played a key role in skeletal muscle protein degradation. BO but not SO reduced the LPS-induced increase in toll-like receptor 4 (TLR4) expression and activation of mitogen-activated protein kinases (MAPKs) and NF-κB in gastrocnemius muscle. In summary, supplementation with BO is more effective than supplementation with SO in preventing LPS-induced inflammation and muscle wasting. Blockade of the TLR4/MAPKs/NF-κB pathway is crucial in the action of BO on LPS-induced inflammation and wasting in skeletal muscle.

18-Carbon polyunsaturated fatty acids via down-regulation NF-κB activation reduce lipopolysaccharide-induced myotube atrophy

Muscle atrophy often occurs in cachexia of various inflammation-related diseases. Systemic inflammation and the inflammatory pathway contribute to cachexia-induced muscle atrophy, which is associated with activation of two major protein degradation systems, the ubiquitin–proteasome pathway (UPP) and the autophagy–lysosomal pathway (ALP). The aim of this study was to explore the effects of linoleic acid, alpha-linolenic acid, and gamma-linolenic acid, 18-carbon polyunsaturated fatty acids (PUFAs), on lipopolysaccharide (LPS)-induced myotube atrophy and possible mechanisms of these actions. Our data demonstrated that these three test 18-carbon PUFAs significantly inhibited LPS-induced C2C12 myotube atrophy as well as activation of UPP and ALP, as evidenced by decreases in LPS-induced expression of muscle-specific ring finger protein 1, protein ubiquitination, and microtubule-associated protein 1 light chain 3B. Moreover, the 18-carbon PUFAs diminished LPS-induced expression of pro-inflammatory cytokines and phosphorylated mitogen-activated protein kinases as well as the transcriptional activity of nuclear factor-κB (NF-κB). Notably, the 18-carbon PUFAs did not reverse LPS-induced atrophy in C2C12 myotubes transfected with a constitutively active mutant IκB kinase-β plasmid, which suggests the importance of the inhibition of NF-κB activation by the 18-carbon PUFAs. Our findings suggest that the 18-carbon PUFAs are beneficial for improving cachexia-induced myotube atrophy in inflammation-related diseases.

Predicted Glycemic Index and Glycemic Index of Rice Varieties Grown in Taiwan

Two cooked brown rice and six white rice varieties were selected for assessing the variations in predicted glycemic index (pGI) determined by using in vitro starch digestion and the glycemic index (GI) determined in vivo. Marked varietal differences in apparent amylose content, dietary fiber content, pGI, and GI were observed. Most of the tested rice samples were classified as medium-GI foods. The varieties Khazar and Taikeng 9 were categorized as high-GI foods when bread was used as the reference. But brown and white rice samples of TRGC9152 and Taichung Sen 17 fell into the low-GI category when glucose was used as the reference. A significant correlation coefficient (r = 0.946) was found between pGI and GI of rice samples by using bread as the reference with a regression equation of GI = 28.778 + 0.717 × pGI (R2 = 0.8951, P ≤ 0.001). Overall, the in vitro pGI measurement is a rapid and useful method to predict the GI of cooked rice samples.