Neural crest cells (NCCs) are an embryonic migratory cell population with the ability to differentiate into a wide variety of cell types that contribute to the craniofacial skeleton, cornea, peripheral nervous system, and skin pigmentation. This ability suggests the promising role of NCCs as a source for cell-based therapy. Although several methods have been used to induce human NCCs (hNCCs) from human pluripotent stem cells (hPSCs), such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), further modifications are required to improve the robustness, efficacy, and simplicity of these methods. Chemically defined medium (CDM) was used as the basal medium in the induction and maintenance steps. By optimizing the culture conditions, the combination of the GSK3β inhibitor and TGFβ inhibitor with a minimum growth factor (insulin) very efficiently induced hNCCs (70–80%) from hPSCs. The induced hNCCs expressed cranial NCC-related genes and stably proliferated in CDM supplemented with EGF and FGF2 up to at least 10 passages without changes being observed in the major gene expression profiles. Differentiation properties were confirmed for peripheral neurons, glia, melanocytes, and corneal endothelial cells. In addition, cells with differentiation characteristics similar to multipotent mesenchymal stromal cells (MSCs) were induced from hNCCs using CDM specific for human MSCs. Our simple and robust induction protocol using small molecule compounds with defined media enabled the generation of hNCCs as an intermediate material producing terminally differentiated cells for cell-based innovative medicine.

BackgroundAbnormal activation of endochondral bone formation in soft tissues causes significant medical diseases associated with disability and pain. Hyperactive mutations in the bone morphogenetic protein (BMP) type 1 receptor ACVR1 lead to fibrodysplasia ossificans progressiva (FOP), a rare genetic disorder characterized by progressive ossification in soft tissues. However, the specific cellular mechanisms are unclear. In addition, the difficulty obtaining tissue samples from FOP patients and the limitations in mouse models of FOP hamper our ability to dissect the pathogenesis of FOP.MethodsTo address these challenges and develop a “disease model in a dish”, we created human induced pluripotent stem cells (iPS cells) derived from normal and FOP dermal fibroblasts by two separate methods, retroviral integration or integration-free episomal vectors. We tested if the ability to contribute to different steps of endochondral bone formation was different in FOP vs. control iPS cells.ResultsRemarkably, FOP iPS cells showed increased mineralization and enhanced chondrogenesis in vitro. The mineralization phenotypes could be suppressed with a small-molecule inhibitor of BMP signaling, DMH1. Our results indicate that the FOP ACVR1 R206H mutation favors chondrogenesis and increases mineral deposition in vitro.ConclusionsOur findings establish a FOP disease cell model for in vitro experimentation and provide a proof-of-concept for using human iPS cell models to understand human skeletal disorders.

These findings could contribute to the development of biological treatments that aid in the healing of skeletal muscle after injury.

The t(X;18)(p11.2;q11.2) translocation commonly found in synovial sarcoma (SS) results in the fusion of the SYT gene on chromosome 18 to either of two closely related genes, SSX1 and SSX2, on chromosome X. It has been suggested that patients who have SS bearing SYT-SSX1 fusion have worse prognosis than those bearing SYT-SSX2 fusion. However, little is known about the biologic basis or the relationship with the histopathologic risk factors in regard to the different fusion types. We analyzed 19 cases of SS with no metastasis at diagnosis. These tumors were classified by reverse transcription-polymerase chain reaction to SYT-SSX1 and SYT-SSX2 types. The expression of Ki-67, p27, p53, and bcl-2 and various clinicopathologic parameters including mitotic rate were compared between the two fusion types. The SYT-SSX1 type fusion was associated with high Ki-67 expression (P ‫؍‬ .011) and high mitotic rate (P ‫؍‬ .070). No significant differences were found between the two types as to the expression of p27, p53, and bcl-2 and other clinicopathologic parameters. The survival analysis showed that SYT-SSX1-type fusion, high Ki-67 expression, and high mitotic rate correlated with shorter metastasis-free survival. These data suggested that SYT-SSX fusion type is associated with tumor cell proliferative activity and prognosis of patients who have SS.