1. 5-Lipoxygenase inhibitors attenuate TNF-α-induced inflammation in human synovial fibroblasts.
- Author
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Lin HC, Lin TH, Wu MY, Chiu YC, Tang CH, Hour MJ, Liou HC, Tu HJ, Yang RS, and Fu WM
- Subjects
- Animals, Arachidonate 5-Lipoxygenase deficiency, Arachidonate 5-Lipoxygenase genetics, Chemokine CCL2 blood, Chemokine CCL2 genetics, Chemokine CCL2 metabolism, Edema drug therapy, Edema genetics, Edema metabolism, Edema pathology, Enzyme Activation drug effects, Fibroblasts metabolism, Gene Knockout Techniques, Humans, I-kappa B Kinase metabolism, Inflammation chemically induced, Inflammation drug therapy, Inflammation metabolism, Inflammation pathology, Interleukin-6 genetics, Interleukin-6 metabolism, Leukotriene B4 metabolism, Lipoxygenase Inhibitors therapeutic use, Male, Mice, Mice, Inbred C57BL, Phosphorylation drug effects, Proteolysis drug effects, RNA Interference, RNA, Small Interfering genetics, Arachidonate 5-Lipoxygenase metabolism, Fibroblasts drug effects, Lipoxygenase Inhibitors pharmacology, Synovial Membrane pathology, Tumor Necrosis Factor-alpha adverse effects
- Abstract
The lipoxygenase isoform of 5-lipoxygenase (5-LOX) is reported to be overexpressed in human rheumatoid arthritis synovial tissue and involved in the progress of inflammatory arthritis. However, the detailed mechanism of how 5-lipoxygenase regulates the inflammatory response in arthritis synovial tissue is still unclear. The aim of this study was to investigate the involvement of lipoxygenase pathways in TNF-α-induced production of cytokines and chemokines. Human synovial fibroblasts from rheumatoid patients were used in this study. 5-LOX inhibitors and shRNA were used to examine the involvement of 5-LOX in TNF-α-induced cytokines and chemokines expression. The signaling pathways were examined by Western Blotting or immunofluorescence staining. The effect of 5-LOX inhibitor on TNF-α-induced chemokine expression and paw edema was also explored in vivo in C57BL/6 mice. Treatment with 5-LOX inhibitors significantly decreased TNF-α-induced pro-inflammatory mediators including interleukin-6 (IL-6) and monocyte chemo-attractant protein-1 (MCP-1) in human synovial fibroblasts. Knockdown of 5-LOX using shRNA exerted similar inhibitory effects. The abrogation of NF-κB activation was involved in the antagonizing effects of these inhibitors. Furthermore, 5-LOX inhibitor decreased TNF-α-induced up-regulation of serum MCP-1 level and paw edema in mouse model. Our results provide the evidence that the administration of 5-LOX inhibitors is able to ameliorate TNF-α-induced cytokine/chemokine release and paw edema, indicating that 5-LOX inhibitors may be developed for therapeutic treatment of inflammatory arthritis.
- Published
- 2014
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