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 <i>Brucella</i> infection are still unclear. Herein, the inhibitory effects of ginsenoside Rg3 against intracellular parasitic <i>Brucella</i> infection were evaluated through bacterial infection, adherence assays, and LAMP-1 colocalization, as well as immunoblotting and FACS for detecting MAPK signaling proteins and F-actin polymerization, respectively. The internalization, intracellular growth, and adherence of <i>Brucella abortus</i> in Rg3-treated RAW 264.7 cells were significantly decreased compared with the Rg3-untreated control. Furthermore, an apparent reduction of F-actin content and intensity of F-actin fluorescence in Rg3-treated cells was observed compared with <i>B. abortus</i>-infected 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 <i>B. abortus</i>-containing phagosomes with LAMP-1 was markedly increased in Rg3-treated cells. These findings suggest that ginsenoside Rg3 inhibits <i>B. abortus</i> infection in mammalian cells and can be used as an alternative approach in the treatment of brucellosis.