Figure 1.

miR-302/367 cluster increases bacterial clearance in macrophages and in mice. (A, B) Time-dependent manner of miR-302/367 cluster expression in MH-S cells. MH-S cells were infected with PAO1 (A) or PA14 (B) at MOI 10:1 for 1 h and polymyxin B (100 µg/ml) was added for another 1 h to kill bacteria outside of the cells. The cell samples were also collected at different time points from 1 to 6 h. The miR-302/367 cluster expression in MH-S cells were detected by qRT-PCR. (C–E) MH-S cells were transfected with control (50 nmol/L) or miR-302a and 302b mimics (50 nmol/L) for 24 h followed by PA14 (C), PAO1 (D), or PAK (E) infection at an MOI of 10:1 for 1 h, and intracellular bacterial clearance was determined by CFU assay at the indicated time points. (F–H) MH-S cells were transfected with control (50 nmol/L) or miR-302a and 302b inhibitors (50 nmol/L) for 24 h followed by PA14 (F), PAO1 (G), or PAK (H) infection at an MOI of 10:1 for 1 h, and intracellular bacterial clearance was determined by CFU assay at the indicated time points. (I–K) The mice were i.v. (intravenously) injected with control or miR-302a and miR-302b mimics (10 µg per mouse). Twenty-four hours later, mice were treated with 1 × 10⁷ CFU of PA14 for 6 h. BAL fluid (I), blood (J), and lungs (K) were collected for CFU analysis of bacterial burdens. Data are shown as the mean ± SEM of three independent experiments. *p < 0.05; **p < 0.01, ***p < 0.001.