FIG. 2.

Lentiviral transduction of hMSCs with various promoter reporters. (A) Vector maps for the secreted and nonsecreted luciferase probes showing their structures. (B) BLI and histology (day 21) analysis evidencing that selecting transduced hMSC with puromycin does not affect their chondrogenic potential. FGF2-expanded cells are shown here (similar results obtained with control-expanded cells). (C) Dilution curve showing an increased transduction efficiency in control-expanded (C) versus FGF2-expanded (F) hMSC for both Sox9 and AGG probes. A plateau effect is also seen earlier in control-expanded than in FGF2-expanded cells. (D) Day 2 BLI showing a baseline, high transgene activity for both Sox9 and AGG probes only in chondrogenic cells (hMSCs and human chondrocytes [hChond]) (left panel), which is sensitive to the number of transduced cells used (right panel). In cocultures, hMSC (in bold) were the only cells virally transduced. Early transgene activation is present only in chondrogenic cells as hybrid cultures with human fibroblasts (hFib) exhibited a marginal signal compared with cultures with the same cell ratio made with hChond (50:50 in this case). n = 3 (different donors), one representative set of data shown. BLI, bioluminescence imaging. Color images available online at www.liebertpub.com/tea