Expression of Hmga2 induces collagen deposition in the BM mesenchymal stromal cells. (A) A scheme for the coculture system is shown on the left. MSC culture was first established from the BM of WT mice. MSCs were then re-plated and cultured for 72 hours before SET-2 cells expressing vector or HMGA2 were placed on top of MSCs and cultured for another 72 hours. SET-2 cells were then removed from MSCs. RNA was isolated from the MSCs. RT-qPCR showed increased collagen I and III mRNA expression in MSCs cocultured with SET-2 cells overexpressing HMGA2. Data from 4 independent experiments are shown in bar graphs as mean ± SEM. Stimulation with (B) TGF-β1 (50 ng/mL) or (C) Cxcl12 (100 ng/mL) showed increase in collagen I and III mRNA expression in MSCs compared with unstimulated MSCs. The mRNA expression was assessed by RT-qPCR and normalized by Gapdh. Data from 4 independent experiments are shown in bar graphs as mean ± SEM. (D-E) Immunofluorescence images showing increased expression of collagen I and collagen III in MSCs cocultured with SET-2 cells overexpressing HMGA2 compared with vector expressing SET-2 cells. Stimulation with TGF-β1 (50 ng/mL) or Cxcl12 (100 ng/mL) also increased collagen I and III expression in MSCs. Scale bars, 100 µm. *P < .05.