Glucosamine Inhibits Lipopolysaccharide-Induced Microglial Activation via a Down-Regulation of iNOS Gene

Abstract

This study investigated the effects of glucosamine on lipopolysaccharide (LPS)-induced cellular activation, inducible nitric oxide synthase (iNOS) expression in microglia, and the molecular and signaling mechanisms involved. LPS with 100 ng/mL was used for activation of BV2 microglial cells. LPS-induced mRNA and protein expressions for iNOS and other signaling factors were analyzed by reverse-transcription polymerase chain reaction and Western blot analysis, respectively. Glucosamine attenuated LPS-induced iNOS protein and mRNA expression in doseand time-dependent manners, but did not affect iNOS protein stability. However, the inhibitory actions of glucosamine on LPS-induced iNOS expressions were independent of nuclear factor-κB signals and mitogen-activated protein kinases activations. Glucosamine inhibited LPS-induced phosphorylation of ribosomal p85 S6, translational regulatory protein, which may down-regulate translation in iNOS mRNA. These results suggest that inhibitory action mechanisms of glucosamine on LPS-induced microglial activation include down-regulation of microglial activator gene iNOS herein.