Abstract

This study aimed to investigate the role of autophagy in the inhibition of Brucella-containing vacuole (BCV) and lysosome fusion in Brucella suis 1330 infected murine macrophage RAW264.7 cells. Autophagosome induction was observed following B. suis 1330 infection. The autophagic pathway was inhibited pharmacologically by 3-methylademine (3-MA) treatment or by RNAi-mediated depletion of the autophagy related gene, LC3. Compared with controls, suppression of the autophagic pathway was associated with a significant decrease in B. suis 1330 internalization (P<0.05) and reduction in the detection of B. suis-containing vacuole and lysosome fusion by fluorescence colocalization. These results implicate autophagy in the inhibition of BCV-lysosome fusion which favors the survival of B. suis 1330 in murine macrophage RAW264.7 cells.

Key words: Brucella suis 1330, autophagy, BCV-lysosome fusion, colocalization.

Abbreviation

Abbreviations: BCV, Brucella-containing vacuole; CFU, colony forming units; DMEM,Dulbecco’s Modified Eagle’s Medium; FBS, fetal bovine serum; GFP, green fluorescent protein; MOI, multiplicity of infection; MTT, 3-(4,5-Dimethylthiazol-2-yl) -2, 5-diphenyl tetrazolium bromide; PBS, phosphate buffered saline; 3-MA, 3-methylademine; MDC,monodansylcadaverine; TRD, Texas red-dextran.