Immunocytochemistry of primary human fibroblasts (F-18) transfected with miRNA-449a inhibitor or miRNA-449a mimics. SERPINE1 strongly marked the fibroblasts transfected with miRNA-449a inhibitor (Figure 7 A + B) compared to miRNA-449a mimics which virtually blocks SERPINE1 protein expression (Figure 7 C + D). Non transfected primary human fibroblasts cultured under hypoxia showed SERPINE1 protein labeling in some cells (Figure 7 E + F). DAB immunostaining with mAb against SERPINE1 protein counterstained with haematoxylin. Magnification in Figure 7 A, C, E: 100×; Figure 7 B, D, F: 200×; brown: SERPINE1 positive fibroblasts; blue: nuclei (two independent experiments).