Glutamine (GLN) can inhibit NF-kappa B activation and cytokine expression following sepsis. NF-kappa B activation and inflammatory cytokine expression, depend on neddylation of Cullin-1 (Cul-1) to proceed. Our aim was to evaluate whether GLN inhibits Cul-1 neddylation, and further determine if GLN-mediated Cul-1 deneddylation attenuates NF-kappa B activation and subsequent cytokine expression following experimental sepsis in the mouse. Sepsis-induced via cecal ligation and puncture (CLP) led to a significant increase in lung Cul-1 neddylation. GLN administration post-sepsis led to enhanced lung Cul-1 deneddylation and attenuated NEDD8 expression (p < 0.01 vs. saline). Cul-1 deneddylation was associated with decreased NF-kappa B activation and I kappa B alpha degradation in GLN treated mice (*p < 0.01 vs. saline). Lastly, GLN treatment led to a significant decrease in lung TNF-alpha and IL-6 post-sepsis. These are the first data describing a direct effect of GLN on Cul-1 deneddylation and provide a possible mechanistic explanation for GLN's anti-inflammatory effects. (c) 2008 Elsevier Inc. All rights reserved.