Abstract
The ability to inhibit host macrophage apoptosis is one of the survival strategies of intracellular bacteria, including Brucella. In the present study the role of Mg2+/Mn2+ dependent protein phosphatase 1A (PPM1A) in the apoptosis of Brucella suis (B. suis) strain 2 vaccine-infected BV2 cells was investigated. Compared with control cells, the protein expression levels of cleaved caspase-3 were markedly increased in PPM1A short hairpin (sh)RNA-transfected BV2 cells. Flow cytometry analysis showed that treatment with JNK activator anisomycin significantly increased the rate of apoptosis in BV2 cells in comparison with the control cells. Furthermore, PPM1A shRNA significantly increased the levels of JNK phosphorylation and the levels of cleaved caspase-3 in BV2 cells infected with B. suis strain 2 in comparison with the control cells. DAPI staining showed nuclear condensation in B. suis infected BV2 cells transfected with PPM1A shRNA in comparison with the control shRNA cells. Flow cytometry analysis showed that PPM1A shRNA significantly increased the percentage of apoptotic BV2 cells infected with B. suis strain 2 compared with those transfected with control shRNA. Taken together, these data suggested that knockdown of PPM1A promotes apoptosis in B. suis strain 2-infected BV2 cells and that PPM1A may be a potential target in the development of treatments to inhibit intracellular growth of B. suis.