title: Wnt signaling behaves as a "master regulator" in the osteogenic and adipogenic commitment of human amniotic fluid mesenchymal stem cells.
abstract: Human amniotic fluid mesenchymal stem cells (huAFMSCs) are emerging as a promising therapeutic option in regenerative medicine. Here, we characterized huAFMSC phenotype and multipotentiality. When cultured in osteogenic medium, huAFMSC displayed a significant increase in: Alkaline Phosphatase (ALP) activity and mRNA expression, Alizarin Red S staining and Runx2 mRNA expression; whereas maintaining these cells in an adipogenic culture medium gave a time-dependent increase in PPARγ and FABP4 mRNA expression, glycerol-3-phosphate dehydrogenase (GPDH) activity and positivity to Oil Red Oil staining. These results confirm that huAFMSCs can differentiate toward osteogenic and adipogenic phenotypes. The canonical Wnt/ßcatenin signaling pathway appears to trigger huAFMSC osteoblastogenesis, since during early phases of osteogenic differentiation, the expression of Dishevelled-2 (Dvl-2), of the non-phosphorylated form of ß-catenin, and the phosphorylation of glycogen synthase kinase-3ß (GSK3ß) at serine 9 were upregulated. On the contrary, during adipogenic differentiation Dvl-2 expression decreased, whereas that of ß-catenin remained unchanged. This was associated with a late increase in GSK3ß phosphorylation. Consistent with this scenario, huAFMSCs exposure to Dickkopf-1, a selective inhibitor of the Wnt signaling, abolished Runx2 and ALP mRNA upregulation during huAFMSC osteogenic differentiation, whereas it enhanced FABP4 expression in adipocyte-differentiating cells. Taken together, these results unravel novel molecular determinants of huAFMSC commitment towards osteoblastogenesis, which may represent potential targets for directing the differentiation of these cells and improving their use in regenerative medicine.
authors.affiliation: Department of Experimental and Clinical Sciences, University "G. D'Annunzio" of Chieti-Pescara, Chieti, Italy.
authors.forename: Iolanda
authors.initials: I
authors.lastname: D'Alimonte
authors.forename: Angela
authors.initials: A
authors.lastname: Lannutti
authors.forename: Caterina
authors.initials: C
authors.lastname: Pipino
authors.forename: Pamela
authors.initials: P
authors.lastname: Di Tomo
authors.forename: Laura
authors.initials: L
authors.lastname: Pierdomenico
authors.forename: Eleonora
authors.initials: E
authors.lastname: Cianci
authors.forename: Ivana
authors.initials: I
authors.lastname: Antonucci
authors.forename: Marco
authors.initials: M
authors.lastname: Marchisio
authors.forename: Mario
authors.initials: M
authors.lastname: Romano
authors.forename: Liborio
authors.initials: L
authors.lastname: Stuppia
authors.forename: Francesco
authors.initials: F
authors.lastname: Caciagli
authors.forename: Assunta
authors.initials: A
authors.lastname: Pandolfi
authors.forename: Renata
authors.initials: R
authors.lastname: Ciccarelli
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics / Q000502:physiology*; D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000653:Amniotic Fluid / Q000166:cytology; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D000072261:Dishevelled Proteins; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D005993:Glycerolphosphate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics / Q000502:physiology*; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D060449:Wnt Signaling Pathway / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D051176:beta Catenin / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D050659:Core Binding Factor Alpha 1 Subunit; C501126:DKK1 protein, human; C000606581:DVL2 protein, human; D000072261:Dishevelled Proteins; C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; D047495:PPAR gamma; D010750:Phosphoproteins; C493709:RUNX2 protein, human; D051176:beta Catenin; D005993:Glycerolphosphate Dehydrogenase; C471850:glycerol-3-phosphate dehydrogenase, FAD-dependent; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; D000469:Alkaline Phosphatase