Previous studies have investigated the potential relationship between promoter polymorphism (-308, G/ A) of tumor necrosis factor (TNF)-α and various autoimmune diseases. However, results from published data were inconclusive. To verify relationship between TNF-α polymorphism (-308, G/A) and susceptibility to autoimmune diseases such as vitiligo, celiac disease, and rheumatoid arthritis, we have performed a metaanalysis with all relevant articles before October 2016. The electronic search of PubMed, google, and Embase databases was performed to identify eligible studies investigating the relationship of TNF-α polymorphism with autoimmune diseases including vitiligo, celiac disease, and rheumatoid arthritis. Genotype frequency data of TNF-α polymorphism (-308, G/A) were extracted and the meta analysis was performed by Comprehensive meta-analysis program with odds ratio (OR) and 95% confidence intervals (95% CI). Genotype models were applied with dominant and recessive models and allele model analyzed. The final analysis included 37 publication papers with a total of 6,102 autoimmune disease patients and 6,987 control subjects. In result, a statistical significant correlation between TNF-α polymorphism (-308, G/A) and susceptibility to autoimmune disease was not detected in our meta-analysis (p>0.05 in all models). Our results suggest that the TNF-α polymorphism might not be related to the development of autoimmune disease. If further results in larger studies would be accumulated in the future, this relationship would be clarified.

Tumor necrosis factor alpha (TNFα) is a multifunctional inflammatory cytokine that regulates various cellular and bio-logical processes. Increased levels of TNFα have been im-plicated in a number of human diseases including diabetes and arthritis. Sympathetic nervous system stimulation via the beta2-adrenergic receptor (β2AR) in osteoblasts suppresses osteogenic activity. We previously reported that TNFα up- regulates β2AR expression in murine osteoblastic cells and that this modulation is associated with TNFα inhibition of osteoblast differentiation. In our present study, we explored whether TNFα induces β2AR expression in human osteo-blasts and then identified the downstream signaling path-way. Our results indicated that β2AR expression was increa-sed in Saos-2 and C2C12 cells by TNFα treatment, and that this increase was blocked by the inhibition of NF-κB acti-vation. Chromatin immunoprecipitation and luciferase reporter assay results indicated that NF-κB directly binds to its cog-nate elements on the β2AR promoter and thereby stimulates β2AR expression. These findings suggest that the activation of TNFα signaling in osteoblastic cells leads to an upregu-lation of β2AR and also that TNFα induces β2AR exp-ression in an NF-κB-dependent manner.

Enterococcus faecalis, a gram-positive bacterium, has been implicated in endodontic infections, particularly in chronic apical periodontitis. Proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), are involved in the pathogenesis of these apical lesions. E. faecalis has been reported to stimulate macrophages to produce TNF-α. The present study investigated the mechanisms involved in TNF-α production by a murine macrophage cell line, RAW 264.7 in response to exposure to E. faecalis. Both live and heat-killed E. faecalis induced high levels of gene expression and protein release of TNF-α. Treatment of RAW 264.7 cells with cytochalasin D, an inhibitor of endocytosis, prevented the mRNA up-regulation of TNF-α by E. faecalis. In addition, antioxidant treatment reduced TNF-α production to baseline levels. Inhibition of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinase also significantly attenuated E. faecalis-induced TNF-α expression by RAW 264.7 cells. Furthermore, activation of NF-κB and AP-1 in RAW 264.7 cells was also stimulated by E. faecalis. These results suggest that the phagocytic uptake of bacteria is necessary for the induction of TNF-α in E. faecalis-stimulated macrophages, and that the underlying intracellular signaling pathways involve reactive oxygen species, ERK, p38 MAP kinase, NF-κB, and AP-1.

Nitric oxide(NO) is a labile, uncharged, reactive radical that functions as a sensitive mediator of intercellular communication in diverse tissues. It has been reported that NO is produced by osteoblast and these results may suggest that NO is integrally involved in the regulation of osteoclast formation and osteoclast resorption activity by osteoblastic cells. We examined the effect of cytokines on NO release by mouse bone marrow cell. We also examined the effects of cytokines and sodium nitroprusside(SNP) on the formation of osteoclast-like cell from mouse bone marrow cells in culture. Cytokines stimulated NO production of mouse bone marrow cells, and N-nitro-L-arginine methyl ester, a specific inhibitor of NO synthase, suppressed the cytokine-induced NO production. SNP showed dual action in the generation of osteoclasts. The addition of (30μM)SNP inhibited the formation of tartrate resistant acid phosphatase(TRAP)(+) multinucleated cell, whereas lower concentration(30μM) of SNP enhanced it. Although the precise action of NO remains to be elucidated in detail, the action of NO in osteoclast generation in our studies seems to be associated, at least in part, with bone metabolism and bone pathophysiology.

To search for immunoactive natural products exerting anti-inflammatory activity, we have evaluated the effects on the water extracts of Artemisia princeps Pampanini (APP) on lipopolysaccharide-induced nitric oxide (NO), tumor necrosis factor-α (TNF-α), and prostaglandin E2 (PGE2) production by RAW 264.7 macrophage cell line. Our data indicate that this extract is a potent inhibitor of NO production and it also significantly decreased PGE2 and TNF-α production. Consistent with these results, the protein and mRNA expression level of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) was inhibited by water extracts of APP in a dose-dependent manner. These results suggest that APP may exert anti-inflammatory and analgesic effects possibly by suppressing the inducible NO synthase and COX-2 expressions.

To search for immunoactive natural products exerting anti-inflammatory activity, we have evaluated the effects of the ethanol extracts of Rubus coreanus Miq. (ERC) on lipopolysaccharide-induced nitric oxide (NO), tumor necrosis factor-α (TNF-α), and Interferon-γ (IFN-γ) production by RAW 264.7 macrophage cell line. Our data indicate that this extract is a potent inhibitor of NO production and it also significantly decreased IFN-γ and TNF-α production. Consistent with these results, the protein level of inducible Nitric Oxide Synthase (iNOS) and cyclooxygenase-2 (COX-2) was inhibited by ethanol extracts of ERC in a dose-dependent manner. These results suggest that ERC may exert anti-inflammatory and analgesic effects possibly by suppressing the inducible NO synthase and COX-2 expressions.

Naturally occurring substances are important biomedical resources with low toxicity and ethnopharmacology-based efficacy. Four out of 45 extracts (Celastrus orbiculatus, Cercis chinensis, Stephanadra incisa, and Weigela subsessilis) prepared from the bark of Korea Forest plants exhibited more than 50% of inhibition on TNF-α production in lipopolysaccharide (LPS)-activated RAW264.7 cells at 100 μg/ml. In particular, potential inhibitory components of 4 extracts showed more than 50% inhibition seemed to be concentrated in methylene chloride (MC) fraction from C. orbiculatus, in ethyl acetate (EtOAc) fraction from C. chinensis and in hexane (Hx) fraction from S. incisa, whereas inhibitory activities of W. subssilis were broadly seen in non-polar solvent fractions such as Hx, MC and EtOAc. Therefore, our results suggest that extracts from C. orbiculatus, C. chinensis, S. incisa and W. subsessilis may be developed as a therapeutic remedy against TNF-α-mediated diseases such as rheumatoid arthritis or further fractionated to isolate active components having antiTNF-α inhibitory activity.