Figure 4.

miR-148a-3p promotes macrophage phagocytosis and bactericidal activity. (A) BM-derived macrophages derived from normal mice were transfected with miR-148a-3p mimic or N.C. and stimulated with PBS (M0), lipopolysaccharide (LPS) + interferon (IFN)-γ (M1), or interleukin (IL)-4 (M2). Then, macrophages (1 × 10⁶) were cocultured with E. coli (1 × 10⁷) that had been transformed with an EGFP-expression vector for 2 h. Subsequently, the cells were washed and analyzed by FACS (n = 4). (B) The percentage of macrophages that had been engulfed by bacteria was compared between the miR-148a-3p mimic- and N.C.-transfected macrophages (n = 4). (C) The mean fluorescent intensity (MFI) of EGFP was compared between the miR-148a-3p mimic- and N.C.-transfected macrophages (n = 4). (D,E) Macrophages engulfing EGFP⁺ bacteria were photographed under a fluorescence microscope (D) and macrophages containing engulfed bacteria (green dots) were counted, and the numbers of bacteria per macrophage quantified and compared (E) (n = 3). (F) Macrophages that had engulfed EGFP⁺ E. coli were cultured for 6 h. Cells were then lysed and plated on ampicillin-containing agar plates. Bacterial colonies were counted and compared after overnight culture (n = 3). Bars, mean ± SD; *P < 0.05; **P < 0.01.