Legionella pneumophila-Derived Outer Membrane Vesicles Promote Bacterial Replication in Macrophages
Fig 5
OMVs induce miR-146a upregulation which augments bacterial replication.
(A+B) THP-1 cells were pre-incubated with OMVs (0.1, 1, 10 μg/mL) or LPS/IFN-γ for 20 h and then infected with L. pneumophila (MOI 0.5) for 24 h and 48 h, respectively. qPCR was performed for miR-146a (A) and pri-mir-146a (B). Mean values of three independent experiments are shown. (C+D) THP-1 cells were transfected with miR-146a mimic or inhibitor and corresponding controls. After 24 h of transfection, cells were PMA-differentiated and RNA samples were taken after 24 h incubation. qPCR for miR-146a was performed (C). (D) Transfected THP-1 cells were then additionally infected with L. pneumophila (MOI 0.5) and lysed for CFU 24 and 48 h p.i., respectively. Results are depicted relative to control transfected cells. Mean values of three independent experiments are shown. Statistics: A+B: Mann-Whitney test; *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001 compared to corresponding 0 μg/mL OMVs. # p<0.05 compared to equally treated 0 h sample. C+D: Mann-Whitney test; *p<0.05, ***p<0.001 compared to corresponding control transfected sample. # p<0.05 compared to miR-146a mimic transfection.