Fig. 4
MSC-let-7a administration dramatically inhibited PASMC proliferation and reduced its resistance to apoptosis. The rPASMCs were exposed to hypoxia or normoxia for 24 h, followed by co-culture with modified MSCs (MSC-NC or MSC-let-7a) using the transwell system. Approximately 24 h after incubation, PASMCs were collected. Cell viability was analyzed by 3H-TdR (a). Cells were lysed with RIPA lysis buffer, followed by SDS–PAGE. The specimens were then subjected to Western blotting analysis. The protein levels of Ki67, cyclin D1, p21, and PCNA were monitored by Gel DocTM XR imaging system (b). The corresponding quantitative analysis was also carried out by Image J software (c). For cell apoptosis assay, about 10 μl Annexin V-FITC and 5 μl PI was introduced. Flow cytometry was used to detect cell apoptosis (d, e). The caspase-3 activity was also determined using a commercial kit to assess cell apoptosis (f). *p < 0.05. MSC mesenchymal stem cell, NC miR-control, PCNA proliferating cell nuclear antigen