Interleukin-10 inhibits tumor necrosis factor-α production in lipopolysaccharide-stimulated RAW 264.7 cells through reduced MyD88 expression

Background— Class A macrophage scavenger receptor (SR-A) is a macrophage-restricted multifunctional molecule that optimizes the inflammatory response by modulation of the activity of inflammatory cytokines. This study was conducted with SR-A–deficient (SR-A −/− ) mice to evaluate the relationship between SR-A and cardiac remodeling after myocardial infarction. Methods and Results— Experimental myocardial infarction (MI) was produced by ligation of the left coronary artery in SR-A −/− and wild-type (WT) male mice. The number of mice that died within 4 weeks after MI was significantly greater in SR-A −/− mice than in WT mice ( P =0.03). Importantly, death caused by cardiac rupture within 1 week after MI was 31% (17 of 54 mice) in SR-A −/− mice and 12% (6 of 51 mice) in WT mice ( P =0.01). In situ zymography demonstrated augmented gelatinolytic activity in the infarcted myocardium in SR-A −/− mice compared with WT mice. Real-time reverse transcription–polymerase chain reaction at day 3 after MI showed that the expression of matrix metalloproteinase-9 mRNA increased significantly in the infarcted myocardium in SR-A −/− mice compared with WT mice. Furthermore, SR-A −/− mice showed augmented expression of tumor necrosis factor-α and reduction of interleukin-10 in the infarcted myocardium at day 3 after MI. In vitro experiments also demonstrated increased tumor necrosis factor-α and decreased interleukin-10 expression in activated SR-A −/− macrophages. Conclusions— The present findings suggest that SR-A deficiency might cause impairment of infarct remodeling that results in cardiac rupture via insufficient production of interleukin-10 and enhanced expression of tumor necrosis factor-α and of matrix metalloproteinase-9. SR-A might contribute to the prevention of cardiac rupture after MI.

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Alpha-Lipoic Acid Suppresses Extracellular Histone-Induced Release of the Infammatory Mediator Tumor Necrosis Factor-α by Macrophages

Cellular Physiology and Biochemistry ◽

10.1159/000480217 ◽

2017 ◽

Vol 42 (6) ◽

pp. 2559-2568 ◽

Cited By ~ 3

Author(s):

Ping Chang ◽

Juan Liu ◽

Ying Yu ◽

Shao-Ye Cui ◽

Zhen-Hui Guo ◽

...

Keyword(s):

Tumor Necrosis Factor ◽

Signaling Pathways ◽

Tumor Necrosis ◽

Tumor Necrosis Factor Α ◽

Raw 264.7 ◽

Alpha Lipoic Acid ◽

Tnf Α ◽

Extracellular Histones ◽

Factor Α ◽

Necrosis Factor

Background/Aims: This study investigated signaling pathways via which extracellular histones induce the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) release from the macrophage cell line RAW 264.7 and the anti-inflammatory efficacy of the antioxidant alpha-lipoic acid (ALA). Methods: ELISA and western blotting analyses were conducted to detect the release of TNF-α from histone-stimulated RAW 264.7 macrophages and the associated phospho-activation of MAPKs (ERK and p38) and NF-κB p65. The effects of ALA on the release of TNF-α and phospho-activation of the MAPKs and NF-κB p65 were studied. P < 0.05 was considered statistically significant. Results: Extracellular histones dose-dependently induced TNF-α release from RAW 264.7 cells and increased the phosphorylation of p38, ERK, and NF-κB p65. TNF-α release was markedly suppressed by p38, ERK, and NF-kB inhibitors. ALA reduced histone-induced TNF-α release, ERK/p38 MAPK activation, and NF-kB activation without affecting macrophage viability. Conclusion: Histones induce TNF-α release from macrophages by activating the MAPK and NF-kB signaling pathways, while ALA suppresses this response by inhibiting ERK, p38 and NF-kB. These findings identify potentially critical inflammatory signaling pathways in sepsis and molecular targets for sepsis treatment.

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