Fig. 5.

MiR-128 regulates CM proliferation through targeting Suz12. a In vitro, evaluation of CM proliferation by immunofluorescence staining of Ki67 in miR-128^−/− (Nkx2.5^Cre; miR-128^fl/fl) neonatal CMs transfected with either scrambled control siRNA (si-Ctrl) or Suz12 siRNA (si-Suz12). Cells are counter-stained with DAPI to visualize nuclei and with antibody to cTnT to identify CMs. Scale bars, 40 µm. b Expression of Suz12 in miR-128^−/− neonatal CMs transfected with either a scrambled control siRNA (si-Ctrl) or Suz12 siRNA (si-Suz12) (n = 5). c Quantification of CM proliferation by Ki67 immunostaining (n = 12 samples, ~150 CMs/sample). d Schematic diagram depicting the protocol for siRNA and EdU intraperitoneal (i.p.) injection for P1 mice. e CM size analysis by WGA and cTnT staining in si-Ctrl and si-Suz12 treated miR-128^−/− hearts at P7 (n = 5 mice, ~300 CMs/heart). Scale bars, 50 µm (yellow); 10 µm (white). f Comparison of EdU⁺ CMs in si-Ctrl and si-Suz12-treated miR-128^−/− hearts at P7 (n = 5 mice, ~400 CMs/heart).). Scale bars, 50 µm (yellow), 20 µm (white). g, h Western blot analysis of cell cycle-related genes in si-Ctrl and si-Suz12 treated miR-128^−/− hearts at P7 (n = 3). i Proposed model by which miR-128 deletion promotes CM proliferation through coordinating the expression of cell cycle-related genes. Statistical significance was calculated using Student’s t-test in b, c, e, f, and h. Data are represented as means ± SEM. *P < 0.05