Fig. 4

Fibrillary components of FN, COL1, and COL3 in the stem cell-generated ECM. Western blot results of FN, COL1, and COL3 in the cell sheets and dECM generated by hADSCs, hBMSCs, and hCDPCs. A, cell sheet formed by hADSCs; dA, dECM from hADSC cell sheet; B, cell sheet formed by hBMSCs; dB, dECM from hBMSC cell sheet; C, cell sheet formed by hCDPCs; dC, dECM from CDPC cell sheet. FN: fibronectin fragments, ~ 90 kDa (bands at ~ 263 kDa under non-reducing conditions can be found in Additional file 1: Fig. S1); COL1, collagen type I, intracellular c-terminal-COL1 propeptide can be found at ~ 30 kDa; mature ECM COL1 at ~ 130 kDa (arrows from bottom to top indicate the α1 chain of COL1, procollagen, and (α1)2 dimer of COL1, respectively); COL3, collagen type III, monomer at ~ 138 kDa, and dimer at ~ 270 kDa. The same amounts of protein (5 μg protein/lane) were loaded into each well, and SDS-PAGE was performed under reducing conditions. The experiment was repeated at least three times, with at least two technical replicates for each trial. The data were quantified using Image J (NIH, USA), normalized with group A, and a representative trial is presented. Full-length blots/gels are presented in Additional file 1: Figs. S2–S4. hADSCs, human adipose-derived stem cells; hBMSCs, human bone marrow-derived stem cells; hCDPCs, human cartilage-derived progenitor cells; ECM, extracellular matrix; dECM, decellularized ECM; SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis