Intracellular Trafficking Modulation by Ginsenoside Rg3 Inhibits Brucella abortus Uptake and Intracellular Survival within RAW 264.7 Cells

Abstract

Ginsenoside Rg3, a saponin extracted from ginseng, has various pharmacological and biological activities; however, its effects against Brucella infection are still unclear. Herein, the inhibitory effects of ginsenoside Rg3 against intracellular parasitic Brucella infection were evaluated through bacterial infection, adherence assays, and LAMP1 colocalization, as well as immunoblotting and FACS for detecting MAPK signaling proteins and Factin polymerization, respectively. The internalization, intracellular growth, and adherence of Brucella abortus in Rg3treated RAW 264.7 cells were significantly decreased compared with the Rg3untreated control. Furthermore, an apparent reduction of Factin content and intensity of Factin fluorescence in Rg3treated cells was observed compared with B. abortusinfected cells without treatment by flow cytometry analysis and confocal microscopy, respectively. In addition, treating cells with Rg3 decreased the phosphorylation of MAPK signaling proteins such as ERK 1/2 and p38 compared with untreated cells. Moreover, the colocalization of B. abortuscontaining phagosomes with LAMP1 was markedly increased in Rg3treated cells. These findings suggest that ginsenoside Rg3 inhibits B. abortus infection in mammalian cells and can be used as an alternative approach in the treatment of brucellosis.