Docosahexaenoic acid （DHA) differentially affects TNFα and IL-6 expression in LPS-stimulated RAW 264.7 murine macrophages

Docosahexaenoic acid(DHA) differentially affects TNFα and IL-6 expression in LPS-stimulated RAW 264.7 murine macrophages.

TNFα-induced airway smooth muscle cell proliferation depends on endothelin receptor signaling, GM-CSF and IL-6

vitamin C downregulates TNF-alpha-induced ICAM-1 expression via the inhibition of NF-kappaB activation

nitric oxide and endothelin-1, the yin and yang on vascular function
NO is a more potent inhibitor of ET-1-mediated elevated arterial pressure(/airway smooth muscle cell) than other pressor pathways, due in part to inhibition of intravascular pressure-independent release of ET-1.
vitamin c is a booster of NO synthase
nitrates and nitrites are precusor of NO.

Prostaglandins Leukot Essent Fatty Acids. 2015 Jun; 97: 27–34.
Published online 2015 Apr 11. doi: 10.1016/j.plefa.2015.03.002

Docosahexaenoic acid(DHA) differentially affects TNFα and IL-6 expression in LPS-stimulated RAW 264.7 murine macrophages

Kaori L. Honda, Stefania Lamon-Fava, Nirupa R. Matthan, Dayong Wu, and Alice H. Lichtenstein*

Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA 02111, USA

Docosahexaenoic acid (DHA) is generally reported to have anti-inflammatory properties, however, prior work has documented differential effects on individual pro-inflammatory cytokines: reduced IL-6, but not TNFα, mRNA expression in macrophages. To elucidate the mechanism, the roles of prostaglandin E2 (PGE2), cyclic AMP response element-binding protein (CREB), and NFκB were examined in RAW 264.7 macrophages. DHA did not influence CREB activity, but significantly reduced PGE2 production by 41% and NFκB activity by 32%. Exogenous PGE2 inhibited TNFα mRNA expression dose dependently. Unexpectedly, inhibiting PGE2 production with NS-398 also decreased TNFα mRNA expression, suggesting a concentration-dependent dual role of PGE2 in regulating TNFα expression. IL-6 expression was unaffected by endogenous or exogenous PGE2. Partial block of NFκB activation (SN50; 46%, or, BAY-11-7082; 41%) lowered IL-6 to a greater extent than TNFα mRNA expression. The differential effect of DHA on TNFα and IL-6 mRNA expression may be mediated via reduction in NFκB activity.

Keywords: TNFα, IL-6, TLR4, Macrophages, PGE2, CREB

Docosahexaenoic acid differentially affects TNFα and IL-6 expression in LPS-stimulated RAW 264.7 murine macrophages
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562472/

TNFα-induced airway smooth muscle cell proliferation depends on endothelin receptor signaling, GM-CSF and IL-6

JürgenKnoblochaSarah DeryaYanikaSandraKörberaErichStoelbenbDavidJungckaAndreaKocha

Abstract
Pathological proliferation of human airway smooth muscle cells (HASMCs) causes hyperplasia in chronic lung diseases. Signaling pathways that link airway inflammation to HASMC proliferation might provide therapeutic targets for the prevention of airway remodeling and chronic lung diseases. Endothelin-1 (ET-1) signals via endothelin-A- and B-receptors (ETAR, ETBR) to perpetuate HASMC-associated and TNFα-dependent inflammatory processes.

Hypothesis: endothelin receptor antagonists (ERAs) suppress HASMC proliferation induced by inflammatory cytokines. HASMCs were stimulated ex vivo with cytokines in the presence or absence of ERAs (ETAR-specific/selective: BQ123, ambrisentan; ETBR-specific: BQ788; non-selective: bosentan, macitentan, ACT-132577) or cytokine-blocking antibodies. Cell counts, DNA-synthesis (BrdU-incorporation assay), cytokine production (ELISA) and ETBR expression (whole-genome microarray data, western blot) were analyzed.

ET-1-induced HASMC proliferation and DNA-synthesis were reduced by protein kinase inhibitors and ETAR-specific/selective ERAs but not by BQ788. TNFα-induced HASMC proliferation and DNA-synthesis were reduced by all ERAs. TNFα induced ET-1 and ETBR expression. TNFα- and ET-1-induced GM-CSF releases were both reduced by BQ123 and BQ788. TNFα- and ET-1-induced IL-6 releases were both reduced by BQ123 but not by BQ788. Combined but not single blockade of GM-CSF-receptor-α-chain and IL-6 reduced TNFα- and ET-1-induced HASMC proliferation and DNA-synthesis. Combined but not single treatment with GM-CSF and IL-6 induced HASMC proliferation and DNA-synthesis in the presence of ET-1.

In conclusion, TNFα induces HASMC proliferation via ET-1/GM-CSF/IL-6. ETBR requires up-regulation by TNFα to mediate ET-1 effects on HASMC proliferation. This signaling cascade links airway inflammation to HASMC-associated remodeling processes and is sensitive to ERAs. Therefore, ERAs could prevent inflammation-induced airway smooth muscle hyperplasia.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC444845

Dietary vitamin C is essential for humans, primates, guinea pigs, and several other animals and insects that lack l-gulono-γ-lactone oxidase, the final enzyme in its biosynthetic pathway from glucose ().Under physiological conditions, vitamin C predominantly exists in its reduced form, ascorbic acid (AA); it also exists in trace quantities in the oxidized form, dehydroascorbic acid (DHA).

Cited by: 115
Publish Year: 2004

https://www.ncbi.nlm.nih.gov/pubmed/11120850

12/15/2000 · Inhibition of TNF-driven IKK activation was mediated by p38 mitogen-activated protein kinase, because treatment of cells with vitamin C led to a rapid and sustained activation of p38, and the specific p38 inhibitor SB203580 reversed the inhibitory effect of vitamin C on IKK activity, I-kappaBalpha phosphorylation, and NF-kappaB activation.

Cited by: 316
Publish Year: 2000

Eicosapentaenoic acid prevents endothelin-1-induced cardiomyocyte hypertrophy in vitro through the suppression of TGF-β1 and phosphorylated JNK
Nobutake Shimojo, Subrina Jesmin, Sohel Zaedi, Seiji Maeda, Masaaki Soma,

The cardiovascular benefit of fish oil in humans and experimental animals has been reported. Endothelin (ET)-1 is a well-known cardiac hypertrophic factor. However, although many studies link a fish oil extract, eicosapentaenoic acid (EPA), to cardiac protection, the effects of EPA on cardiac hypertrophy and underlying mechanism(s) are unclear. The present study investigated whether EPA prevents ET-1-induced cardiomyocyte hypertrophy; the potential pathways likely to underlie such an effect were also investigated. Cardiomyocytes were isolated from neonatal rat heart, cultured for 3 days, and then treated for 24 h with vehicle only (control), treated with 0.1 nM ET-1 only, or pretreated with 10 μM EPA and then treated with 0.1 nM ET-1. The cells were harvested, and changes in cell surface area, protein synthesis, expression of a cytoskeletal (α-actinin) protein, and cell signaling were analyzed. ET-1 induced a 97% increase in cardiomyocyte surface area, a 72% increase in protein synthesis rate, and an increase in expression of α-actinin and signaling molecule [transforming growth factor-β1 (TGF-β1), c-Jun NH2-terminal kinase (JNK), and c-Jun]. Development of these ET-1-induced cellular changes was attenuated by EPA. Moreover, the hypertrophied cardiomyocytes showed a 1.5- and a 1.7-fold increase in mRNA expression of atrial and brain natriuretic peptides, the classical molecular markers of cardiac hypertrophy, respectively; these changes were also suppressed by EPA. Here we show that ET-1 induces cardiomyocyte hypertrophy and expression of hypertrophic markers, possibly mediated by JNK and TGF-β1 signaling pathways. These ET-1-induced effects were blocked by EPA, a major fish oil ingredient, suggesting that fish oil may have beneficial protective effects on cardiac hypertrophy.

Eicosapentaenoic acid prevents endothelin-1-induced cardiomyocyte hypertrophy in vitro through the suppression of TGF-β1 and phosphorylated JNK | American Journal of Physiology-Heart and Circulatory Physiology
https://journals.physiology.org/doi/full/10.1152/ajpheart.01365.2005

Arch Pharm Res . 2004 Oct; 27(10):1073-9.
Vitamin C blocks TNF-alpha-induced NF-kappaB activation and ICAM-1 expression in human neuroblastoma cells

Eun-Wha Son 1, Sung-Ji Mo, Dong-Kwon Rhee, Suhkneung Pyo

Abstract
Interactions of the cell adhesion molecules are known to play important roles in mediating inflammation. The proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), activates the NF-kappaB signaling pathway, which induces the expression of various genes, such as intercellular adhesion molecule-1 (ICAM-1). In this study, the effect of vitamin C on the ICAM-1 expression induced by TNF-alpha in a human neuroblastoma cell line, SK-N-SH was investigated. Treatment with vitamin C resulted in the downregulation of the TNF-alpha-induced surface expression and ICAM-1 mRNA levels in a concentration-dependent manner. Moreover, a gel shift analysis indicated that vitamin C dose-dependently inhibited the NF-kappaB activation and IkappaBalpha degradation induced by TNF-alpha.

Taken together, these results suggest that vitamin C downregulates TNF-alpha-induced ICAM-1 expression via the inhibition of NF-kappaB activation.

Eicosapentaenoic acid (EPA) prevents endothelin-1-induced cardiomyocyte hypertrophy.

vitamin C downregulates TNF-alpha-induced ICAM-1 expression via the inhibition of NF-kappaB activation

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