ABSTRACT
Objective: Our knowledge of human neural crest stem cells (NCSCs) is expanding, owing to recent advances in technologies utilizing human-induced pluripotent stem cells (hiPSCs) that generate NCSCs. However, the clinical application of these technologies requires the reduction of xeno-materials. To overcome this significant impediment, this study aimed to devise a novel method to induce NCSCs from hiPSCs without using a feeder cell layer.Materials and Methods: hiPSCs were cultured in feeder-free maintenance media containing the Rho-associated coiled-coil forming kinase inhibitor Y-27632. When the cells reached 50–70% confluence, differentiation was initiated by replacing the medium with knockout serum replacement (KSR) medium containing Noggin and SB431542. The KSR medium was then gradually replaced with increasing concentrations of Neurobasal medium from day 5 to 11.Results: Immunocytochemistry and flow cytometry were performed 12 days after induction of differentiation and revealed that the cells generated from hiPSCs expressed the NCSC markers p75 and HNK-1, but not the hiPSC marker SOX2.Conclusion: These findings demonstrate that hiPSCs were induced to differentiate into NCSCs in the absence of feeder cells.
ABSTRACT
CD57 (synonyms: Leu-7, HNK-1) is a well-known marker of nerve elements including the conductive system of the heart, as well as natural killer cells. In lung specimens from 12 human fetuses at 10–34 weeks of gestation, we have found incidentally that segmental, subsegmental, and more peripheral arteries strongly expressed CD57. Capillaries near developing alveoli were often or sometimes positive. The CD57-positive tissue elements within intrapulmonary arteries seemed to be the endothelium, internal elastic lamina, and smooth muscle layer, which corresponded to tissue positive for a DAKO antibody reactive with smooth muscle actin we used. However, the lobar artery and pulmonary arterial trunk as well as bronchial arteries were negative. Likewise, arteries in and along any abdominal viscera, as well as the heart, thymus, and thyroid, did not express CD57. Thus, the lung-specific CD57 reactivity was not connected with either of an endodermal- or a branchial arch-origin. CD57 antigen is a sugar chain characterized by a sulfated glucuronic acid residue that is likely to exist in some glycosphingolipids. Therefore, a chemical affinity or an interaction might exist between CD57-positive arterioles and glycosphingolipids originating from alveoli, resulting in acceleration of capillary budding to make contact with the alveolar wall. CD57 might therefore be a functional marker of the developing air-blood interface that characterizes the fetal lung at the canalicular stage.