Fig. 5

Modulation of the STAT3-BCL3 axis enhances survival induced by ischemic stress. a Endothelial colony-forming cells (ECFCs) were exposed to hypoxia for various times (0–24 h). BCL3 expression was detected by western blot analysis. b ECFCs were transfected with STAT3-siRNA for 48 h prior to exposure to hypoxic conditions for 24 h. BCL3 was detected by western blot analysis. c ECFCs were transfected with BCL3-siRNA for 48 h prior to exposure to hypoxic conditions for 96 h. Cleaved caspase-3 was detected by western blot analysis. d ECFCs were transfected with BCL3-siRNA for 48 h prior to treatment with H₂O₂ (10⁻³ M) for 8 h followed by western blot analysis for cleaved caspase-3. e Co-immunofluorescence staining was used to detect apoptosis (caspase-3, an apoptosis marker, red) and nor-ECFCs, hypo-ECFCs, si-BCL3/hypo-ECFCs, or scramble siRNA/hypo-ECFCs (human nuclear antigen (HNA)-positive cells, green). DAPI (blue) was used for nuclear staining. Arrows indicate caspase-3⁺/HNA⁺/DAPI⁺ cells (scale bar: 50 μm). f Quantitative analysis of caspase-3/HNA/DAPI triple-positive cells conducted 3 days after transplantation of nor-ECFCs, hypo-ECFCs, si-BCL3/hypo-ECFCs, or scramble siRNA/hypo-ECFCs. **P < 0.01 vs. nor-ECFCs; ^## P < 0.01 vs. hypo-ECFCs; ^$$ P < 0.01 vs. si-STAT3/hypo-ECFC; n = 10