Fig. 6: β-catenin functionally regulates myocardial repair of PBMSCs in infarcted hearts through direct targeting of Oct4.

a Kaplan–Meier survival rates. b–e Echocardiography of LVFS (b), LVEDD (c), LVEDV (d), and LVAWd (e) before MI (pre-MI, baseline), 1 d after MI (1 d post-MI), 30 d after MI (30 d post-MI) and 90 d after MI (90 d post-MI). Transplantation of the PBMSCs pretreated with β-catenin or Oct4 transfection had higher survival rates and resulted in significant improvement in cardiac function and structural remodeling. However, this effect was abolished in the shβ-catenin or shOct4 groups (oeβ-catenin+shOct4) and was rescued by combination with Oct4 transfection (shβ-catenin+oeOct4). For determination of the effects of the oeβ-catenin- or oeOct4-transfected MSCs on left ventricle structure at 90 days after MI, hearts were stained with TTC, Masson’s trichrome, or hematoxylin and eosin. f Quantitation of infarct size as determined by TTC staining at 90 d post-MI. g Morphometric measurements of the scar/LV area revealed a smaller scar in the oeβ-catenin- or oeOct4-transfected PBMSC-treated groups and a larger scar in the shβ-catenin- or shOct4-transfected PBMSC-treated groups than in the PBMSC- and PBS-treated groups. h Morphometric measurements of the viable cardiomyocytes in rat hearts from the different groups showed significantly larger areas of cardiomyocytes in the hearts treated with oeβ-catenin or oeOct4-transfected PBMSCs than with PBMSCs alone, shβ-catenin or shOct4-transfected PBMSCs and PBS. i Representative histological images of left ventricular basal, middle, and apex cross-sections after TTC staining in the PBS, PBMSC, and oeβ-catenin-, oeOct4- or shOct4-transfected PBMC groups. TTC-stained images were cut into transverse sections to assess the infarct size (percentage of the area of the entire LV, f). The surviving myocardium was stained brick red by TTC staining, and the infarcted myocardium was pale white (black arrows). In the oeβ-catenin- or oeOct4-transfected PBMC groups, the ischemic area was significantly smaller than that in the PBS and shOct4-transfected PBMC groups, suggesting a positive effect of β-catenin/Oct4-overexpressing PBMSCs on the infarcted hearts. j, k Collagen density measured by Masson’s trichrome staining was lower in the oeβ-catenin- or oeOct4-transfected PBMC-treated animals after 90 days. The infarct zone of the oeβ-catenin- or oeOct4-transfected PBMC-treated groups contained islands of viable cardiomyocytes (red, k, red arrows, Label, 50 μm). l H&E staining showing different levels of fibrocyte infiltration and inflammation in the ischemic area. Label, 100 μm. All graphical data are shown as the means ± SEMs. P < 0.05: *vs. PBS injection, ^#vs. PBMSC therapy alone, ^Δvs. transplantation of oeβ-catenin, oeOct4-transfected PBMSCs, or shβ-catenin plus oeOct4, ^†vs. transplantation of PBMSCs transfected with oeβ-catenin plus shOct4 or shβ-catenin alone, ^§vs. pre-MI, ^║vs. 1d post-MI, ^¶vs. 30 d post-MI. b–e Pre-MI and 1 d post-MI, n = 20 per group. At 30 d post-MI, PBS injection, n = 15; cell therapy: PBMSCs alone, n = 18; oeβ-catenin-treated PBMSCs, n = 18; shβ-catenin-treated PBMSCs, n = 16; PBMSCs treated with oeβ-catenin plus shOct4, n = 16; PBMSCs treated with shβ-catenin plus oeOct4, n = 19; PBMSCs treated with oeOct4, n = 19; and PBMSCs treated with shOct4, n = 16. At 90 d post-MI, PBS injection, n = 11; cell therapy: PBMSCs alone, n = 12; oeβ-catenin-treated PBMSCs, n = 18; shβ-catenin-treated PBMSCs, n = 11; PBMSCs treated with oeβ-catenin plus shOct4, n = 13; PBMSCs treated with shβ-catenin plus oeOct4, n = 17; PBMSCs treated with oeOct4, n = 19; and PBMSCs treated with shOct4, n = 12. (f–h, n = 5, each group).