Brucella abortushijacks the host protein Slc2a1via the SepA effector to promote intracellular survival in macrophages

Brucella spp. are facultative intracellular bacteria that infect and induce brucellosis in a diverse range of mammalian hosts. The disease causes major global economic losses and also is a worldwide threat to public health security. Characterization of bacterial and host factors that promote intracellular survival of Brucella is key for the prevention and control of brucellosis. In this study, we identified proteins involved in intracellular survival of Brucella abortus A19 in RAW264.7 macrophage cells by liquid chromatography-mass spectrometry of macrophages with or without B. abortus infection. The functions of these proteins, the signaling pathways in which the proteins participate, the domain entries enriched by the proteins, and the subcellular localization of the differentially-expressed proteins were deciphered. Differential protein expression revealed that Slc2a1, which is a key Glycolytic protein, was significantly upregulated in infected macrophage cells. This observation was confirmed by qRT-PCR and Western blotting studies. The role of Slc2a1 in the intracellular survival of B. abortus was probed by overexpressing and knocking down SLC2A1 in RAW264.7 cells. Overproduction of the protein promoted intracellular proliferation of B. abortus whereas knockdown of SLC2A1 inhibited proliferation of the bacterium. Finally, we determined that the Secreted Effector Protein A (SepA) effector of B. abortus enhanced SLC2A1 expression in macrophage cells. Thus, B. abortus stimulates host SLC2A1 expression via the SepA effector protein to aid bacterial survival in the macrophage environment which suggests that SepA may be a novel antibacterial target to combat Brucella infection.