• 대한의생명과학회지
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• 제22권1호
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• pp.1-8
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• 2016

Several studies have investigated the various effects of dexamethasone (Dex) on the proliferation and differentiation of mesenchymal stem cells (MSCs). Previously, we reported that co-treatment with L-ascorbic acid 2-phosphate and fibroblast growth factor (FGF)-2 maintained differentiation potential in MSCs through expression of hepatocyte growth factor (HGF). In this study, we investigated the effects of co-treatment with FGF-2 and Dex on the proliferation and differentiation potential of MSCs during a 2-month culture period. Co-treatment with FGF-2 and Dex increased approximately a 4.7-fold higher accumulation rate of MSC numbers than that by FGF-2 single treatment during a 2-month culture period. Interestingly, co-treatment with FGF-2 and Dex increased expression of HGF and maintained adipogenic differentiation potential during this culture period. These results suggest that co-treatment with FGF-2 and Dex preserves the proliferation and differentiation potential during long-term culture.

• KSBB Journal
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• 제27권5호
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• pp.273-280
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• 2012

Graphene is a one-atom-thick sheet composed of carbon atoms only. It has a two-dimensional honeycomb structure with $sp^2$ orbital bonding, which presents some unique properties. Due to large Young's modulus, good electrical conductivity, ability to immobilize several kinds of small molecules and proteins, and biocompatibility of graphene, it has attracted interests inits ability to enhance cell growth and differentiation, followed by recent several studies. We reviewed about the osteogenic differentiation of mesenchymal stem cells, and neurogenic differentiation of neuron stem cells, and the ectodermal and mesodermal differentiation of induced pluripotent stem cells using graphene. Graphene has not only enhanced the adhesion and proliferation of mesenchymal stem cells, but also led to the faster differentiation even without any other exogenous signals. Nonetheless, graphene has some cytotoxicities in its amount-response manner, which is critical to regenerative medicine. The cytotoxicities of graphene were compared with those of grapheneoxide and carbon nanotubes.

• Reproductive and Developmental Biology
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• 제35권1호
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• pp.9-15
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• 2011

The functional cardiovascular system is comprised of distinct mesoderm-derived lineages including endothelial cells, vascular smooth muscle cells and other mesenchymal cells. Recent studies in the human embryonic stem cell differentiation model have provided evidence indicating that these cell lineages are developed from the common progenitors such as hemangioblasts and cardiovascular progenitor cells. Also, the studies have suggested that these progenitors have a common primordial progenitor, which expresses KDR (human Flk-1, also known as VEGFR2, CD309). We demonstrate here that sustained activation of BMP4 (bone morphogenetic protein 4) in hESC line, CHA15 hESC results in $KDR^+$ mesoderm specific differentiation. To determine whether the $KDR^+$ population derived from hESCs enhances potential to differentiate along multipotential mesodermal lineages than undifferentiated hESCs, we analyzed the development of the mesodermal cell types in human embryonic stem cell differentiation cultures. In embryoid body (EB) differentiation culture conditions, we identified an increased expression of $KDR^+$ population from BMP4-stimulated hESC-derived EBs. After induction with additional growth factors, the $KDR^+$ population sorted from hESCs-derived EBs displays mesenchymal, endothelial and vascular smooth muscle potential in matrix-coated monolayer culture systems. The populations plated in monolayer cultures expressed increased levels of related markers and exhibit a stable/homologous phenotype in culture terms. In conclusion, we demonstrate that the $KDR^+$ population is stably isolated from CHA15 hESC-derived EBs using BMP4 and growth factors, and sorted $KDR^+$ population can be utilized to generate multipotential mesodermal progenitors in vitro, which can be further differentiated into cardiovascular specific cells.

• Molecules and Cells
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• 제19권1호
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• pp.31-38
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• 2005

Human embryonic stem (hES) cells have unique features including unlimited growth capacity, expression of specific markers, normal karyotypes and an ability to differentiate. Many investigators have tried to use hES cells for cell-based therapy, but there is little information about the properties of available hES cell lines. We compared the characteristics of three hES cell lines. The expression of SSEA-1, -3, -4, and APase, was examined by immunocytochemistry, and Oct-4 expression was analyzed by RT-PCR. Differentiation of the hES cells in vitro and in vivo led to the formation of embryoid bodies (EBs) or teratomas. We examined the expression of tissue-specific markers in the differentiated cells by semiquantitative RT-PCR, and the ability of each hES cell line to proliferate was measured by flow cytometry of DNA content and ELISA. The three hES cell lines were similar in morphology, marker expression, and teratoma formation. However there were significant differences (P < 0.05) between the differentiated cells formed by the different cell lines in levels of expression of tissue-specific markers such as renin, kallikrein, Glut-2, ${\beta}-$ and ${\delta}-globin$, albumin, and ${\alpha}1-antitrypsin$ (${\alpha}1-AT$). The hES cell lines also differed in proliferative activity. Our observations should be useful in basic and clinical hES cell research.

• BMB Reports
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• 제49권12호
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• pp.655-661
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• 2016

Polymer brush is a soft material unit tethered covalently on the surface of scaffolds. It can induce functional and structural modification of a substrate's properties. Such surface coating approach has attracted special attentions in the fields of stem cell biology, tissue engineering, and regenerative medicine due to facile fabrication, usability of various polymers, extracellular matrix (ECM)-like structural features, and in vivo stability. Here, we summarized polymer brush-based grafting approaches comparing self-assembled monolayer (SAM)-based coating method, in addition to physico-chemical characterization techniques for surfaces such as wettability, stiffness/elasticity, roughness, and chemical composition that can affect cell adhesion, differentiation, and proliferation. We also reviewed recent advancements in cell biological applications of polymer brushes by focusing on stem cell differentiation and 3D supports/implants for tissue formation. Understanding cell behaviors on polymer brushes in the scale of nanometer length can contribute to systematic understandings of cellular responses at the interface of polymers and scaffolds and their simultaneous effects on cell behaviors for promising platform designs.

• International Journal of Stem Cells
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• 제16권2호
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• pp.135-144
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• 2023

Background and Objectives: Melanocyte (MC), derived from neural crest stem cell (NCSC), are involved in the production of melanin. The mechanism by which NCSC differentiates to MC remains unclear. N6-methyladenosine (m6A) modification was applied to discuss the potential mechanism. Methods and Results: NCSCs were isolated from hair follicles of rats, and were obtained for differentiation. Cell viability, tyrosinase secretion and activity, and transcription factors were combined to evaluated the MC differentiation. RT-qPCR was applied to determine mRNA levels, and western blot were used for protein expression detection. Total m6A level was measured using methylated RNA immunoprecipitation (MeRIP) assay, and RNA immunoprecipitation was used to access the protein binding relationship. In current work, NCSCs were successfully differentiated into MCs. Fat mass and obesity associated gene (FTO) was aberrant downregulated in MCs, and elevated FTO suppressed the differentiation progress of NCSCs into MCs. Furthermore, microphthalmia-associated transcription factor (Mitf), a key gene involved in MC synthesis, was enriched by FTO in a m6A modification manner and degraded by FTO. Meanwhile, the suppression functions of FTO in the differentiation of NCSCs into MCs were reversed by elevated Mitf. Conclusions: In short, FTO suppressed the differentiating ability of hair follicle-derived NCSCs into MCs by m6A modifying Mitf.

• The Korean Journal of Pain
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• 제32권4호
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• pp.245-255
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• 2019

Stem cells are attracting attention as a key element in future medicine, satisfying the desire to live a healthier life with the possibility that they can regenerate tissue damaged or degenerated by disease or aging. Stem cells are defined as undifferentiated cells that have the ability to replicate and differentiate themselves into various tissues cells. Stem cells, commonly encountered in clinical or preclinical stages, are largely classified into embryonic, adult, and induced pluripotent stem cells. Recently, stem cell transplantation has been frequently applied to the treatment of pain as an alternative or promising approach for the treatment of severe osteoarthritis, neuropathic pain, and intractable musculoskeletal pain which do not respond to conventional medicine. The main idea of applying stem cells to neuropathic pain is based on the ability of stem cells to release neurotrophic factors, along with providing a cellular source for replacing the injured neural cells, making them ideal candidates for modulating and possibly reversing intractable neuropathic pain. Even though various differentiation capacities of stem cells are reported, there is not enough knowledge and technique to control the differentiation into desired tissues in vivo. Even though the use of stem cells is still in the very early stages of clinical use and raises complicated ethical problems, the future of stem cells therapies is very bright with the help of accumulating evidence and technology.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2004년도 춘계학술발표대회
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• pp.272-272
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• 2004

The objective of this study is to test whether human embryonic stem cells expressing Nurr1 (Nurr1-transfected hES cells) could be expressed TH according to neuronal differentiation. As an effort to direct differentiation of hES (MB03 registered in NIH) cells to dopamine-producing neuronal cells, Nurr1 was transfected using conventional transfection protocol into MB03 cell and examined the expression of tyrosine hydroxylase (TH) after differentiation induced by retinoic acid (RA) and ascorbic acid (AA). (omitted)

• BMB Reports
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• 제54권10호
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• pp.505-515
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• 2021

Human pluripotent stem cells (hPSCs) include human embryonic stem cells (hESCs) derived from blastocysts and human induced pluripotent stem cells (hiPSCs) generated from somatic cell reprogramming. Due to their self-renewal ability and pluripotent differentiation potential, hPSCs serve as an excellent experimental platform for human development, disease modeling, drug screening, and cell therapy. Traditionally, hPSCs were considered to form a homogenous population. However, recent advances in single cell technologies revealed a high degree of variability between individual cells within a hPSC population. Different types of heterogeneity can arise by genetic and epigenetic abnormalities associated with long-term in vitro culture and somatic cell reprogramming. These variations initially appear in a rare population of cells. However, some cancer-related variations can confer growth advantages to the affected cells and alter cellular phenotypes, which raises significant concerns in hPSC applications. In contrast, other types of heterogeneity are related to intrinsic features of hPSCs such as asynchronous cell cycle and spatial asymmetry in cell adhesion. A growing body of evidence suggests that hPSCs exploit the intrinsic heterogeneity to produce multiple lineages during differentiation. This idea offers a new concept of pluripotency with single cell heterogeneity as an integral element. Collectively, single cell heterogeneity is Janus-faced in hPSC function and application. Harmful heterogeneity has to be minimized by improving culture conditions and screening methods. However, other heterogeneity that is integral for pluripotency can be utilized to control hPSC proliferation and differentiation.

• 한국발생생물학회지:발생과생식
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• 제15권4호
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• pp.339-347
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• 2011

Human eyelid adipose-derived stem cells (hEAs) and amniotic mesenchymal stem cells (hAMs) are very valuable sources for the cell therapeutics. Both types of cells have a great proliferating ability in vitro and a multipotency to differentiate into adipocytes, osteoblasts and chondrocytes. In the present study, we evaluated their stem cell characteristics after long-time cryopreservation for 6, 12 and 24 months. When frozen-thawed cells were cultivated in vitro, their cumulative cell number and doubling time were similar to freshly prepared cells. Also they expressed stem cell-related genes of SCF, NANOG, OCT4, and TERT, ectoderm-related genes of NCAM and FGF5, mesoderm/endoderm-related genes of CK18 and VIM, and immune-related genes of HLA-ABC and ${\beta}$2M. Following differentiation culture in appropriate culture media for 2-3 weeks, both types of cells exhibited well differentiation into adipocyte, osteoblast, and chondrocyte, as revealed by adipogenic, osteogenic or chondrogenic-specific staining and related genes, respectively. In conclusion, even after long-term storage hEAs and hAMs could maintain their stem cell characteristics, suggesting that they might be suitable for clinical application based on stem cell therapy.