Genistein suppresses tumor necrosis factor α-induced inflammation via modulating reactive oxygen species/Akt/nuclear factor κB and adenosine monophosphate-activated protein kinase signal pathways in human synoviocyte MH7A cells

Abstract

Aims: Genistein, an isofavone derivative found in soy, is known as a promising treatment for rheumatoid arthritis (RA). However, the detailed molecular mechanism of genistein in suppression of proinflammatory cytokine production remains ambiguous. The aim of this work was to evaluate the signal pathway by which genistein modulates inflammatory cytokine expression. Materials and methods: MH7A cells were stimulated with tumor necrosis factor (TNF)-α and incubated with genistein, and interleukin (IL)-1β, IL-6, and IL-8 production was measured by enzyme-linked immunosorbent assay. Nuclear translocation of nuclear factor (NF)-κB was measured by a confocal fuorescence microscopy. The intracellular accumulation of reactive oxygen species (ROS) was monitored using the fluorescent probe 5-6-chloromethyl-2′,7′-dichlorodihydrofuorescein diacetate. Signal-transduction protein expression was measured by Western blot. results: Genistein decreased the secretion of IL-1p, IL-6, and IL-8 from (TNF)-α-stimulated MH7A cells in a dose-dependent manner. Genistein prevented (TNF)-α-induced NF-κB translocation as well as phosphorylation of IκB kinase-a/p and IκBcx, and also suppressed (TNF)-α-induced AMPK inhibition. The production of IL-1β, IL-6, and IL-8 induced by (TNF)-α was decreased by the phosphatidylinositol-3 kinase inhibitor LY294002, suggesting that inhibition of Akt activation might inhibit IL-1β, IL-6, and IL-8 production induced by (TNF)-α. In addition, we also found that pretreatment with the adenosine monophosphate-activated protein kinase (AMPK) agonist 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside obviously inhibited (TNF)-α-induced proinflammatory cytokine production. These observations suggest that the inhibitory effect of genistein on (TNF)-α-induced proinflammatory cytokine production is dependent on AMPK activation. Conclusion: These fndings indicate that genistein suppressed (TNF)-α-induced inflammation by inhibiting the ROS/Akt/NF-κB pathway and promoting AMPK activation in MH7A cells. © 2014 Li et al.