AUTHOR=Gómez Leonardo A. , Alvarez Francisco I. , Molina Raúl E. , Soto-Shara Rodrigo , Daza-Castro Carla , Flores Manuel R. , León Yrvin , Oñate Angel A. 

TITLE=A Zinc-Dependent Metalloproteinase of Brucella abortus Is Required in the Intracellular Adaptation of Macrophages

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.01586

DOI=10.3389/fmicb.2020.01586

ISSN=1664-302X

ABSTRACT=<p><italic>Brucella abortus</italic> is a pathogen that survives in macrophages. Several virulence factors participate in this process, including the open reading frame (ORF) BAB1_0270 codifying for a zinc-dependent metalloproteinase (ZnMP). Here, its contribution in the intracellular adaptation of <italic>B. abortus</italic> was analyzed by infecting RAW264.7 macrophages with the mutant <italic>B. abortus</italic> Δ270 strain. Results showed that this ZnMP did not participated in either the adherence or the initial intracellular traffic of <italic>B. abortus</italic> in macrophages. Nevertheless, its deletion significantly increased the co-localization of <italic>B. abortus</italic> Δ270 with phagolysosomal cathepsin D and reduced its co-localization with calnexin present in endoplasmic reticulum (RE)-derived vesicles. Although <italic>B. abortus</italic> Δ270 showed an upregulated expression of genes involved in virulence (<italic>vjbR</italic>, <italic>hutC</italic>, <italic>bvrR</italic>, <italic>virB1</italic>), it was insufficient to reach a successful intracellular replication within macrophages. Furthermore, its attenuation favored in macrophages infected the production of high levels of cytokines (TNF-α and IL-6) and co-stimulatory proteins (CD80 and CD86), signals required in T cell activation. Finally, its deletion significantly reduced the ability of <italic>B. abortus</italic> Δ270 to adapt, grow and express several virulence factors under acidic conditions. Based on these results, and considering that this ZnMP has homology with ImmA/IrrE proteases, we discuss its role in the virulence of this pathogen, concluding that ZnMP is required in the intracellular adaptation of <italic>B. abortus</italic> 2308 during the infection of macrophages.</p>