Simvastatin Inhibits Invasion into RAW 264.7 Cells through Suppression of the Mevalonate Pathway and Promotes Host Immunity during Infection in a Mouse Model.

Simvastatin is an inhibitor of 3-hydroxy-3-methylglutaryl CoA reductase and has been found to have protective effects against several bacterial infections. In this study, we investigate the effects of simvastatin treatment on RAW 264.7 macrophage cells and ICR mice against () infections. The invasion assay revealed that simvastatin inhibited the invasion into macrophage cells by blocking the mevalonic pathway. The treatment of simvastatin enhanced the trafficking of Toll-like receptor 4 in membrane lipid raft microdomains, accompanied by the increased phosphorylation of its downstream signaling pathways, including JAK2 and MAPKs, upon = infection. Notably, the suppressive effect of simvastatin treatment on invasion was not dependent on the reduction of cholesterol synthesis but probably on the decline of farnesyl pyrophosphate and geranylgeranyl pyrophosphate synthesis. In addition to a direct brucellacidal ability, simvastatin administration showed increased cytokine TNF-α and differentiation of CD8 T cells, accompanied by reduced bacterial survival in spleens of ICR mice. These data suggested the involvement of the mevalonate pathway in the phagocytosis of into RAW 264.7 macrophage cells and the regulation of simvastatin on the host immune system against infections. Therefore, simvastatin is a potential candidate for studying alternative therapy against animal brucellosis.