Effects of glutamine on the nuclear factor-kappaB signaling pathway of murine peritoneal macrophages

The aim of this study was to evaluate the effect of glutamine on the expression of proteins involved in the nuclear factor-kappaB (NF-κB) signaling pathway of murine peritoneal macrophages. Since glutamine is essential for the normal functioning of macrophages, it was hypothesized that in vitro glutamine supplementation would increase NF-κB activation. Peritoneal macrophages were pretreated with glutamine (0, 0.6, 2 and 10 mM) before incubation with lipopolysaccharide (LPS), and the effects of glutamine on the production of tumor necrosis factor-alpha and on the expression and activity of proteins involved in the NF-κB signaling pathway were studied by an enzyme linked immuno-sorbent assay, Western blotting, and an electrophoretic mobility shift assay. Glutamine treatment (2 and 10 mM) increased the activation of NF-κB in LPS-stimulated peritoneal macrophages (P < 0.05). In non-stimulated cells, glutamine treatment (2 and 10 mM) significantly reduced IκB-α protein expression (P < 0.05). Glutamine modulates NF-κB signaling pathway by reducing the level of IκB-α, leading to an increase in NF-κB within the nucleus in peritoneal macrophages.