RhoB is involved in lipopolysaccharide-induced inflammation in mouse in vivo and in vitro

Small GTPase RhoB has been well documented in regulating cell adhesion, motility, proliferation, and survival, but to date, there is little information about the relationship between RhoB and inflammation. In this study, the mRNA and protein levels of RhoB were induced by lipopolysaccharide (LPS) in RAW264.7 cells determined by real-time PCR and Western blot. The upregulation of RhoB by LPS was also observed in mouse peritoneal macrophages and in mouse lung, liver, and kidney. RhoB overexpression by transfecting with wild RhoB plasmid increased the secretion of tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) in RAW264.7 cells, while RhoB knockdown by RNA interference decreased the secretion of TNF-α and NO in RAW264.7 cells. TNF-α and NO synthase are the target genes of nuclear factor-kappaB (NF-κB), and overexpression of RhoB increased, whereas inhibition of RhoB decreased the basal and LPS-activated transcriptional activity of NF-κB in the cells. These results demonstrated that LPS induced RhoB expression in mouse in vivo and in vitro and in RAW264.7 cells, and the role of RhoB on LPS-induced secretion of TNF-α and NO was at least partly mediated via NF-κB. These results indicated that RhoB was involved in LPS-induced inflammation in mouse in vivo and in vitro.