Fig. 3. The upstream regulatory miRNA of SLC26A2 is miR-9-5p. (A) Schematic representation of the miR-9-5p putative binding site in the SLC26A2 3′-UTR. (B) qRT-PCR showed miR-9-5p level in miR-9-5p mimic-transfected HASMCs. (C) Luciferase reporter assays showed that miR-9-5p overexpression remarkably reduced the luciferase activity of the reporter vector containing SLC26A2-wt, but not the reporter vector containing SLC26A2-mut. (D and E) MiR-9-5p mimic was transfected into HASMCs induced by PDGF, qRT-PCR and Western blotting were used to detect the mRNA and protein expression of SLC26A2. Data are presented as the mean±SD of three independent experiments. ^*P<0.05, compared to their respective NCs or scrambled control group, ^†P<0.05, compared to PDGF+mimic-NC group. HASMCs, human airway smooth muscle cells; PGDF, platelet-derived growth factor; NC, negative control.