Figure 3: In vitro differentiation of MSCs with lentivector-enhanced expression of FPR. Panels A–D: Standard differentiation assays for osteogenesis (A & B) and adipogenesis (C & D). Alizarin Red chelates calcium, forming an alizarin red S-calcium complex. Positive staining indicates deposition of calcium phosphate extracellularly (A) and the corresponding fluorescence image (B). Oil Red O is a fat-dissolving dye. Positive staining reflects lipid accumulation in cells (C) and the corresponding fluorescence image (D).