Amniotic fluid stem cells morph into a cardiovascular lineage: analysis of a chemically induced cardiac and vascular commitment

Margherita Maioli,1–3 Giovanni Contini,1 Sara Santaniello,1,2 Pasquale Bandiera,1 Gianfranco Pigliaru,1,2 Raimonda Sanna,5 Salvatore Rinaldi,3 Alessandro P Delitala,1 Andrea Montella,1,5 Luigi Bagella,1,6 Carlo Ventura2–41Department of Biomedical Sciences, University of Sassari, Sassari, 2Laboratory of Molecular Biology and Stem Cell Engineering, National Institute of Biostructures and Biosystems, Bologna, 3Department of Regenerative Medicine, Rinaldi Fontani Institute, Florence, 4Cardiovascular Department, S Orsola-Malpighi Hospital, University of Bologna, Bologna, 5Facility of Genetic and Developmental Biology, AOU Sassari, Sassari, Italy; 6Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USAAbstract: Mouse embryonic stem cells were previously observed along with mesenchymal stem cells from different sources, after being treated with a mixed ester of hyaluronan with butyric and retinoic acids, to show a significant increase in the yield of cardiogenic and vascular differentiated elements. The aim of the present study was to determine if stem cells derived from primitive fetal cells present in human amniotic fluid (hAFSCs) and cultured in the presence of a mixture of hyaluronic (HA), butyric (BU), and retinoic (RA) acids show a higher yield of differentiation toward the cardiovascular phenotype as compared with untreated cells. During the differentiation process elicited by exposure to HA + BU + RA, genes controlling pluripotency and plasticity of stem cells, such as Sox2, Nanog, and Oct4, were significantly downregulated at the transcriptional level. At this point, a significant increase in expression of genes controlling the appearance of cardiogenic and vascular lineages in HA + BU + RA-treated cells was observed. The protein expression levels typical of cardiac and vascular phenotypes, evaluated by Western blotting, immunofluorescence, and flow cytometry, were higher in hAFSCs cultured in the presence of HA + BU + RA, as compared with untreated control cells. Appearance of the cardiac phenotype was further inferred by ultrastructural analysis using transmission and scanning electron microscopy. These results demonstrate that a mixture of HA + BU + RA significantly increased the yield of elements committed toward cardiac and vascular phenotypes, confirming what we have previously observed in other cellular types.Keywords: fetal cells, human amniotic fluid, hyaluronic acid, butyric acid, retinoic acid, prodynorphin, Nkx-2.5, GATA-4, von Willebrand facto