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. Author manuscript; available in PMC: 2011 Nov 7.
Published in final edited form as: Nat Med. 2010 Nov 21;16(12):1400–1406. doi: 10.1038/nm.2252

Figure 3.

Figure 3

Formation of endothelial derived multipotent stem-like cells induced by constitutively active ALK2. (a) Flow cytometry analysis showing co-expression of TIE2 and STRO-1 in endothelial cells expressing mutant ALK2. (b) Immunoblotting showing expression of the mesenchymal stem cell markers STRO-1, CD10, CD44, CD71, CD90, and CD117 in endothelial cells expressing mutant ALK2. Human bone marrow derived mesenchymal stem cells (MSC) express these markers, but human corneal fibroblasts (HCF) do not. β-actin was used as an internal control. (c) Immunoblotting showing increased expression of osteoblast (osterix), chondrocyte (SOX9), or adipocyte (PPARγ2) markers in cells treated with mutant ALK2 for 48 h followed by exposure to osteogenic, chondrogenic, or adipogenic culture medium. (d) Positive staining of osteoblast (alkaline phosphatase and alizarin red), chondrocyte (alcian blue), or adipocyte (oil red O) products in endothelial cell cultures treated with mutant ALK2, but not with vector or wild-type ALK2, for 48 h followed by growth in osteogenic, chondrogenic, or adipogenic culture medium, respectively. Scale bar, 100 μm. (e) Positive staining of osteoblast (alizarin red), chondrocyte (alcian blue), or adipocyte (oil red O) products in polylactic acid scaffolds containing endothelial cells transformed by mutant ALK2 implanted into nude mice, followed by local injection of osteogenic, chondrogenic, or adipogenic medium every 72 h for 6 weeks. Scale bar, 100 μm.