ABSTRACT
Objective: motor neuron differentiation from human embryonic stem cells [hESCs] is a goal of regenerative medicine to provide cell therapy as treatments for diseases that damage motor neurons. Most protocols lack adequate efficiency in generating functional motor neurons. However, small molecules present a new approach to overcome this challenge. The aim of this research is to replace morphogen factors with a cocktail of efficient, affordable small molecules for effective, low cost motor neuron differentiation
Materials and Methods: in this experimental study, hESCs were differentiated into motor neuron by the application of a small molecule cocktail that consisted of dorsomorphin, A8301, and XAV939. During the differentiation protocol, we selected five stages and assessed expressions of neural markers by real-time polymerase chain reaction [PCR], immunofluorescence staining, and flow cytometry. Motor neuron ion currents were determined by whole cell patch clamp recording
Results: immunofluorescence staining and flow cytometry analysis of hESC-derived neural ectoderm [NE] indicated that they were positive for NESTIN [92.68%], PAX6 [64.40%], and SOX1 [82.11%] in a chemically defined adherent culture. The replated [hESC]-derived NE differentiated cells were positive for TUJ1, MAP2, HB9 and ISL1. We evaluated the gene expression levels with real-time reverse transcriptase-PCR at different stages of the differentiation protocol. Voltage gated channel currents of differentiated cells were examined by the whole-cell patch clamp technique. The hESC-derived motor neurons showed voltage gated delay rectifier K[+], Na[+] and Ca[2+] inward currents
Conclusion: our results indicated that hESC-derived neurons expressed the specific motor neuron markers specially HB9 and ISL1 but voltage clamp recording showed small ionic currents therefore it seems that voltage gated channel population were inadequate for firing action potentials
ABSTRACT
In recent years transdifferentiation technology has enabled direct conversion of human fibroblasts to become a valuable, abundant and accessible cell source for patient-specific induced cell generation in biomedical research. The majority of transdifferentiation approaches rely upon viral gene delivery which due to random integration with the host genome can cause genome instability and tumorigenesis upon transplantation. Here, we provide a simple way to induce neural progenitor-like cells from human fibroblasts without genetic manipulation by changing physicochemical culture properties from monolayer culture into a suspension in the presence of a chemical DNA methyltransferase inhibitor agent, Azacytidine. We have demonstrated the expression of neural progenitor-like markers, morphology and the ability to spontaneously differentiate into neural-like cells. This approach is simple, inexpensive, lacks genetic manipulation and could be a foundation for future chemical neural transdifferentiation and a safe induction of neural progenitor cells from human fibroblasts for clinical applications
ABSTRACT
Biomaterial technology, when combined with emerging human induced pluripotent stem cell [hiPSC] technology, provides a promising strategy for patient-specific tissue engineering. In this study, we have evaluated the physical effects of collagen scaffolds fabricated at various freezing temperatures on the behavior of hiPSC-derived neural progenitors [hiPSC-NPs]. In addition, the coating of scaffolds using different concentrations of laminin was examined on the cells. Initially, in this experimental study, the collagen scaffolds fabricated from different collagen concentrations and freezing temperatures were characterized by determining the pore size, porosity, swelling ratio, and mechanical properties. Effects of cross-linking on free amine groups, volume shrinkage and mass retention was also assessed. Then, hiPSC-NPs were seeded onto the most stable three-dimensional collagen scaffolds and we evaluated the effect of pore structure. Additionally, the different concentrations of laminin coating of the scaffolds on hiPSC-NPs behavior were assessed. Scanning electron micrographs of the scaffolds showed a pore diameter in the range of 23-232 Micro m for the scaffolds prepared with different fabrication parameters. Also porosity of all scaffolds was >98% with more than 94% swelling ratio. hiPSC-NPs were subsequently seeded onto the scaffolds that were made by different freezing temperatures in order to assess for physical effects of the scaffolds. We observed similar proliferation, but more cell infiltration in scaffolds prepared at lower freezing temperatures. The laminin coating of the scaffolds improved NPs proliferation and infiltration in a dose-dependent manner. Immunofluorescence staining and scanning electron microscopy confirmed the compatibility of undifferentiated and differentiated hiPSC-NPs on these scaffolds. The results have suggested that the pore structure and laminin coating of collagen scaffolds significantly impact cell behavior. These biocompatible three-dimensional laminin-coated collagen scaffolds are good candidates for future hiPSC-NPs biomedical nerve tissue engineering applications