Docosahexaenoic acid inhibition of inflammation is partially via cross-talk between Nrf2/heme oxygenase 1 and IKK/NF-κB pathways.

We examined the underlying mechanisms involved in n-3 docosahexaenoic acid (DHA) inhibition of inflammation in EA.hy926 cells. The present results demonstrated that pretreatment with DHA (50 and 100 μM) inhibited tumor necrosis factor-alpha (TNF-α)-induced intercellular adhesion molecule 1 (ICAM-1) protein, mRNA expression and promoter activity. In addition, TNF-α-stimulated inhibitory kappa B (IκB) kinase (IKK) phosphorylation, IκB phosphorylation and degradation, p65 nuclear translocation, and nuclear factor-κB (NF-κB) and DNA binding activity were attenuated by pretreatment with DHA. DHA triggered early-stage and transient reactive oxygen species (ROS) generation and significantly increased the protein expression of heme oxygenase 1 (HO-1), induced nuclear factor erythroid 2-related factor 2 (Nrf2) translocation to the nucleus and up-regulated antioxidant response element (ARE)-luciferase reporter activity. Moreover, DHA inhibited Nrf2 ubiquitination and proteasome activity. DHA activated Akt, p38 and ERK1/2 phosphorylation, and specific inhibitors of respective pathways attenuated DHA-induced Nrf2 nuclear translocation and HO-1 expression. Transfection with HO-1 siRNA knocked down HO-1 expression and partially reversed the DHA-mediated inhibition of TNF-α-induced p65 nuclear translocation and ICAM-1 expression. Importantly, we show for the first time that HO-1 plays a down-regulatory role in NF-κB nuclear translocation, and inhibition of Nrf2 ubiquitination and proteasome activity are involved in increased cellular Nrf2 level by DHA. In this study, we show that HO-1 plays a down-regulatory role in NF-κB nuclear translocation and that the protective effect of DHA against inflammation is partially via up-regulation of Nrf2-mediated HO-1 expression and inhibition of IKK/NF-κB signaling pathway.

Yang YC ，Lii CK ，Wei YL ，Li CC ，Lu CY ，Liu KL ，Chen HW ... -  《-》

(-)-7(S)-hydroxymatairesinol protects against tumor necrosis factor-α-mediated inflammation response in endothelial cells by blocking the MAPK/NF-κB and activating Nrf2/HO-1.

Endothelial inflammation is an increasingly prevalent condition in the pathogenesis of many cardiovascular diseases. (-)-7(S)-hydroxymatairesinol (7-HMR), a naturally occurring plant lignan, possesses both antioxidant and anti-cancer properties and therefore would be a good strategy to suppress tumor necrosis factor-α (TNF-α)-mediated inflammation in vascular endothelial cells (VECs). The objective of this study is to evaluate for its anti-inflammatory effect on TNF-α-stimulated VECs and underling mechanisms. The effect of the 7-HMR on suppression of TNF-α-induced inflammation mediators in VECs were determined by qRT-PCR and Western blot. MAPKs and phosphorylation of Akt, HO-1 and NF-κB p65 were examined using Western blot. Nuclear localisation of NF-κB was also examined using Western blot and immunofluorescence. Here we found that 7-HMR could suppress TNF-α-induced inflammatory mediators, such as vascularcelladhesion molecule-1, interleukin-6 and inducible nitric oxide synthase expression both in mRNA and protein levels, and concentration-dependently attenuated reactive oxidase species generation. We further identified that 7-HMR remarkably induced superoxide dismutase and heme oxygenase-1 expression associated with degradation of Kelch-like ECH-associated protein 1 (keap1) and up-regulated nuclear factor erythroid 2-related factor 2 (Nrf2). In addition, 7-HMR time- and concentration-dependently attenuated TNF-α-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK) and Akt, but not p38, or c-Jun N-terminal kinase 1/2. Moreover, 7-HMR significantly suppressed TNF-α-mediated nuclear factor-κB (NF-κB) activation by inhibiting phosphorylation and nuclear translocation of NF-κB p65. Our results demonstrated that 7-HMR inhibited TNF-α-stimulated endothelial inflammation, at least in part, through inhibition of NF-κB activation and upregulation of Nrf2-antioxidant response element signaling pathway, suggesting 7-HMR might be used as a promising vascular protective drug.

Yang D ，Xiao CX ，Su ZH ，Huang MW ，Qin M ，Wu WJ ，Jia WW ，Zhu YZ ，Hu JF ，Liu XH ... -  《-》

Antrodia salmonea inhibits TNF-α-induced angiogenesis and atherogenesis in human endothelial cells through the down-regulation of NF-κB and up-regulation of Nrf2 signaling pathways.

Antrodia salmonea (AS) is known as a traditional Chinese medicine, but very few biological activities have been reported. The present study was aimed to investigate the anti-angiogenic and anti-atherosclerotic potential of the fermented culture broth of AS against tumor necrosis factor-α (TNF-α)-stimulated human endothelial (EA.hy 926) cells. The non-cytotoxic concentrations of AS significantly inhibited TNF-α-induced migration/invasion and capillary-like tube formation in EA.hy 926 cells. Furthermore, AS suppressed TNF-α-induced activity and expression of matrix metalloproteinase-9 (MMP-9), and cell-surface expression of intercellular adhesion molecule-1 (ICAM-1), which was associated with abridged adhesion of U937 leukocytes to endothelial cells. Moreover, AS significantly down-regulated TNF-α-induced nuclear translocation and transcriptional activation of nuclear factor κB (NF-κB) followed by suppression of I-κB degradation and phosphorylation of I-κB kinase-α (IKKα). Notably, the protective effect of AS was directly correlated with the increased expression of hemeoxygenase-1 (HO-1) and γ-glutamylcysteine synthetase (γ-GCLC), which was reasoned by nuclear translocation and transactivation of NF-E2 related factor-2 (Nrf2)/antioxidant response element (ARE). Furthermore, HO-1 knockdown by HO-1-specific shRNA diminished the protective effects of AS on TNF-α-stimulated invasion, tube formation, and U937 adhesion in EA.hy 926 cells. Taken together, these results suggest that Antrodia salmonea may be useful for the prevention of angiogenesis and atherosclerosis.

Yang HL ，Chang HC ，Lin SW ，Senthil Kumar KJ ，Liao CH ，Wang HM ，Lin KY ，Hseu YC ... -  《-》

Induction of heme oxygenase 1 and inhibition of tumor necrosis factor alpha-induced intercellular adhesion molecule expression by andrographolide in EA.hy926 cells.

Yu AL ，Lu CY ，Wang TS ，Tsai CW ，Liu KL ，Cheng YP ，Chang HC ，Lii CK ，Chen HW ... -  《-》

Docosahexaenoic acid attenuates VCAM-1 expression and NF-κB activation in TNF-α-treated human aortic endothelial cells.

This study was conducted to test the hypothesis that n-3 polyunsaturated fatty acids are able to down-regulate expression of adhesion molecules and nuclear factor-κB (NF-κB) activation in vascular endothelial cells, in addition to reducing atherosclerotic lesions in vivo. We report here that docosahexaenoic acid (DHA) reduces atherosclerotic lesions in the aortic arteries of apolipoprotein E knockout (apoE(-/-)) mice. Consistent with the observation in animal study, DHA inhibited THP-1 cell adhesion to tumor necrosis factor α (TNF-α)-activated human aortic endothelial cells (HAECs). Expression of vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) on the cell surface of HAECs was determined by cell-surface enzyme-linked immunosorbent assay. DHA and eicosapentaenoic acid decreased VCAM-1 expression in a dose-dependent manner in TNF-α treated HAECs, while cis-linoleic acid and arachidonic acid did not have any significant effect on either VCAM-1 or ICAM-1 expression. Moreover, DHA significantly reduced VCAM-1 protein expression in the cell lysates of TNF-α-treated HAECs, as determined by Western blot analysis. In line with NF-κB signaling pathway, DHA suppressed the TNF-α-activated IκBα phosphorylation and degradation as well as IκB kinase-β phosphorylation. Subsequently, translocation of the NF-κB (p50/p65) and AP-1 (c-Fos/c-Jun) subunits was down-regulated by DHA in the nucleus of HAECs. These results suggest that DHA negatively regulates TNF-α-induced VCAM-1 expression through attenuation of NF-κB signaling pathway and AP-1 activation. This study provides evidence that DHA may contribute to the prevention of atherosclerosis and inflammatory diseases in vivo.

Wang TM ，Chen CJ ，Lee TS ，Chao HY ，Wu WH ，Hsieh SC ，Sheu HH ，Chiang AN ... -  《-》