Article Induction of the CD24 Surface Antigen in Primary Undifferentiated Human Adipose Progenitor Cells by the Hedgehog Signaling Pathway Francesco Muoio 1 , Stefano Panella 1 , Yves Harder 2,3 and Tiziano Tallone 1,* 1 Foundation for Cardiological Research and Education (FCRE), Cardiocentro Ticino, 6807 Taverne, Switzerland;
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[email protected]; Tel.: +41-91-805-3885 Abstract: In the murine model system of adipogenesis, the CD24 cell surface protein represents a valuable marker to label undifferentiated adipose progenitor cells. Indeed, when injected into the residual fat pads of lipodystrophic mice, these CD24 positive cells reconstitute a normal white adipose tissue (WAT) depot. Unluckily, similar studies in humans are rare and incomplete. This is because it is impossible to obtain large numbers of primary CD24 positive human adipose stem cells (hASCs). This study shows that primary hASCs start to express the glycosylphosphatidylinositol (GPI)-anchored CD24 protein when cultured with a chemically defined medium supplemented with molecules that activate the Hedgehog (Hh) signaling pathway. Therefore, this in vitro system may help understand the biology and role in adipogenesis of the CD24-positive hASCs. The induced Citation: Muoio, F.; Panella, S.; cells’ phenotype was studied by flow cytometry, Real-Time Quantitative Polymerase Chain Reaction Harder, Y.; Tallone, T. Induction of the (RT-qPCR) techniques, and their secretion profile.