• International Journal of Stem Cells
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• 제7권2호
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• pp.108-117
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• 2014

Background and Objectives: Genomic imprinting is an inheritance phenomenon by which a subset of genes are expressed from one allele of two homologous chromosomes in a parent of origin-specific manner. Even though fine-tuned regulation of genomic imprinting process is essential for normal development, no other means are available to study genomic imprinting in human during embryonic development. In relation with this bottleneck, differentiation of human embryonic stem cells (hESCs) into specialized lineages may be considered as an alternative to mimic human development. Methods and Results: In this study, hESCs were differentiated into three lineage cell types to analyze temporal and spatial expression of imprinted genes. Of 19 imprinted genes examined, 15 imprinted genes showed similar transcriptional level among two hESC lines and two human induced pluripotent stem cell (hiPSC) lines. Expressional patterns of most imprinted genes were varied in progenitors and fully differentiated cells which were derived from hESCs. Also, no consistence was observed in the expression pattern of imprinted genes within an imprinting domain during in vitro differentiation of hESCs into three lineage cell types. Conclusions: Transcriptional expression of imprinted genes is regulated in a cell type- specific manner in hESCs during in vitro differentiation.

• IMMUNE NETWORK
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• 제1권3호
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• pp.179-186
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• 2001

Bone marrow stroma is a complex tissue encompassing a number of cell types and supports hematopiesis, differentiation of erythreid, nyel and lymphoid lineages, and also maintains undifferentiated hematopoietic stem cells. Marrow-derived stem cells were composed of two populations, namely, hematopoietic stem cells that can differentiate into blood elements and mesenchymal stem cells that can give rise to connective tissues such as bone, cartilage, muscle, tendon, adipose and stroma. Differentiation requires environmental factors and unique intracellular signaling. For example, $TGF-{\beta}$ or BMP2 induces osteoblastic differentiation of mesenchymal stem are very exciting. However, the intrinsic controls involved in differentiation of stem cells are yet to be understood properly in order to exploit the same. This review presents an overview of the recent developments made in mesenchymal stem cell research with respect to osteogenesis.

• Animal Bioscience
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• 제34권4호
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• pp.533-538
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• 2021

Objective: Pluripotent stem cell-derived lymphatic endothelial cells (LECs) show great promise in their therapeutic application in the field of regenerative medicine related to lymphatic vessels. We tested the approach of forced differentiation of mouse embryonal stem cells into LECs using biodegradable poly lactic-co-glycolic acid (PLGA) nanospheres in conjugation with growth factors (vascular endothelial growth factors [VEGF-A and VEGF-C]). Methods: We evaluated the practical use of heparin-conjugated PLGA nanoparticles (molecular weight ~15,000) in conjugation with VEGF-A/C, embryoid body (EB) formation, and LEC differentiation using immunofluorescence staining followed by quantification and quantitative real-time polymerase chain reaction analysis. Results: We showed that formation and differentiation of EB with VEGF-A/C-conjugated PLGA nanospheres, compared to direct supplementation of VEGF-A/C to the EB differentiation media, greatly improved yield of LYVE1(+) LECs. Our analyses revealed that the enhanced potential of LEC differentiation using VEGF-A/C-conjugated PLGA nanospheres was mediated by elevation of expression of the genes that are important for lymphatic vessel formation. Conclusion: Together, we not only established an improved protocol for LEC differentiation using PLGA nanospheres but also provided a platform technology for the mechanistic study of LEC development in mammals.

• BMB Reports
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• 제49권1호
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• pp.3-10
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• 2016

microRNAs (miRNAs) are key regulators of cell state transition and retention during stem cell proliferation and differentiation by post-transcriptionally downregulating hundreds of conserved target genes via seed-pairing in their 3' untranslated region. In embryonic and adult stem cells, dozens of miRNAs that elaborately control stem cell processes by modulating the transcriptomic context therein have been identified. Some miRNAs accelerate the change of cell state into progenitor cell lineages—such as myoblast, myeloid or lymphoid progenitors, and neuro precursor stem cells—and other miRNAs decelerate the change but induce proliferative activity, resulting in cell state retention. This cell state choice can be controlled by endogenously or exogenously changing miRNA levels or by including or excluding target sites. This control of miRNA-mediated gene regulation could improve our understanding of stem cell biology and facilitate their development as therapeutic tools. [BMB Reports 2016; 49(1): 3-10]

• Reproductive and Developmental Biology
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• 제34권3호
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• pp.143-151
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• 2010

Pluripotency of human embryonic stem cell (hESC) is one of the most valuable ability of hESCs for applying cell therapy field, but also showing side effect, for example teratoma formation. When transplant multipotent stem cell, such as mesnchymal stem cell (MSC) which retains similar differentiation ability, they do not form teratoma in vivo, but there exist limitation of cellular source supply. Accordingly, differentiation of hESC into MSC will be promising cellular source with strong points of both hESC and MSC line. In this study, we described the derivation of MSC like cell population from feeder free cultured hESC (hESC-MSC) using direct differentiation system. Cells population, hESC-MSC and bone marrow derived MSC (BM-MSC) retained similar characteristics in vitro, such as morphology, MSC specific marker expression and differentiation capacity. At the point of differentiation of both cell populations, differentiation rate was slower in hESC-MSC than BM-MSC. As these reason, to verify differentially expressed molecular condition of both cell population which bring out different differentiation rate, we compare the molecular condition of hESC-MSC and BM-MSC using 2-D proteomic analysis tool. In the proteomic analysis, we identified 49 differentially expressed proteins in hESC-MSC and BM-MSC, and they involved in different biological process such as positive regulation of molecular function, biological process, cellular metabolic process, nitrogen compound metabolic process, macromolecule metabolic process, metabolic process, molecular function, and positive regulation of molecular function and regulation of ubiquitin protein ligase activity during mitotic cell cycle, cellular response to stress, and RNA localization. As the related function of differentially expressed proteins, we sought to these proteins were key regulators which contribute to their differentiation rate, developmental process and cell proliferation. Our results suggest that the expressions of these proteins between the hESC-MSC and BM-MSC, could give to us further evidence for hESC differentiation into the mesenchymal stem cell is associated with a differentiation factor. As the initial step to understand fundamental difference of hESC-MSC and BM-MSC, we sought to investigate different protein expression profile. And the grafting of hESC differentiation into MSC and their comparative proteomic analysis will be positively contribute to cell therapy without cellular source limitation, also with exact background of their molecular condition.

• 대한의용생체공학회:의공학회지
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• 제31권2호
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• pp.87-93
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• 2010

Researches for stem cells have been focused on scientists in biomedical sciences as well as clinical application for its great therapeutic potentials. Stem cells have two distinct characteristics: self-renewal and differentiation. In this short review, the links between stem cell research and biomedical engineering is discussed based on the basic characteristics of stem cells. This concept can be extended to the fundamental questions of biological sciences for cells such as proliferation, apoptosis, differentiation, and migration. For understanding proliferation and apoptosis of stem cells, techniques from biomedical engineering such as surface patterning, MEMS, nanotechnologies have been used. The advanced technologies such as microfluidic technologies, three dimensional scaffold fabrication, and mechanical/electrical stimulation have also been used in cell differentiation and migration. Basic and unsolved questions in the stem cell research field have limitations by studying conventional technologies. Therefore, the strategic fusion between stem cell biology and novel biomedical engineering field will break the barriers for understanding fundamental questions of stem cells, which can open the window for the clinical applications of stem cell based therapeutics as well as regeneration of damaged tissues.

• International Journal of Stem Cells
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• 제16권1호
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• pp.44-51
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• 2023

Background and Objectives: DNA methyltransferases (Dnmts) play an important role in regulating DNA methylation during early developmental processes and cellular differentiation. In this study, we aimed to investigate the role of Dnmts in neural differentiation of embryonic stem cells (ESCs) and in maintenance of the resulting neural stem cells (NSCs). Methods and Results: We used three types of Dnmt knockout (KO) ESCs, including Dnmt1 KO, Dnmt3a/3b double KO (Dnmt3 DKO), and Dnmt1/3a/3b triple KO (Dnmt TKO), to investigate the role of Dnmts in neural differentiation of ESCs. All three types of Dnmt KO ESCs could form neural rosette and differentiate into NSCs in vitro. Interestingly, however, after passage three, Dnmt KO ESC-derived NSCs could not maintain their self-renewal and differentiated into neurons and glial cells. Conclusions: Taken together, the data suggested that, although deficiency of Dnmts had no effect on the differentiation of ESCs into NSCs, the latter had defective maintenance, thereby indicating that Dnmts are crucial for self-renewal of NSCs.

• Molecules and Cells
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• 제24권1호
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• pp.1-8
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• 2007

Natural killer (NK) cells play a crucial role in innate immune system and tumor surveillance. NK cells are derived from $CD34^+$hematopoietic stem cells and undergo differentiation via precursor NK cells in bone marrow (BM) through sequential acquisition of functional surface receptors. During differentiation of NK cells, many factors are involved including cytokines, membrane factors and transcription factors as well as microenvironment of BM. NK cells express their own repertoire of receptors including activating and inhibitory receptors that bind to major histocompatibility complex (MHC) class I or class I-related molecules. The balance between activating and inhibitory receptors determines the function of NK cells to kill targets. Binding of NK cell inhibitory receptors to their MHC class I-ligand renders the target cells to be protected from NK cell-mediated cytotoxicity. Thus, NK cells are able to discriminate self from non-self through MHC class I-binding inhibitory receptor. Using intrinsic properties of NK cells, NK cells are emerging to apply as therapeutic agents against many types of cancers. Recently, NK cell alloactivity has also been exploited in killer cell immunoglobulin-like receptor mismatched haploidentical stem cell transplantation to reduce the rate of relapse and graft versus host disease. In this review, we discuss the basic mechanisms of NK cell differentiation, diversity of NK cell receptors, and clinical applications of NK cells for anti-cancer immunotherapy.

• Medical Lasers
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• 제9권2호
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• pp.134-141
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• 2020

The use of stem cell therapy to treat various diseases has become a promising approach. The ability of stem cells to self-renew and differentiate can contribute significantly to the success of regenerative medical treatments. In line with these expectations, there is a great need for an efficient research methodology to differentiate stem cells into their specific targets. Photobiomodulation (PBM), formerly known as low-level laser therapy (LLLT), is a relatively non-invasive technique that has a therapeutic effect on damaged tissue or cells. Recent advances in adapting PBM to stem cell therapy showed that stem cells and progenitor cells respond favorably to light. PBM stimulates different types of stem cells to enhance their migration, proliferation, and differentiation in vitro and in vivo. This review summarizes the effects of PBM on targeted differentiation across multiple stem cell lineages. The analytical expertise gained can help better understand the current state and the latest findings in PBM and stem cell therapy.

• Molecules and Cells
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• 제42권3호
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• pp.200-209
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• 2019

Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have been used as promising tools for regenerative medicine, disease modeling, and drug screening. Traditional and common strategies for pluripotent stem cell (PSC) differentiation toward disease-relevant cell types depend on sequential treatment of signaling molecules identified based on knowledge of developmental biology. However, these strategies suffer from low purity, inefficiency, and time-consuming culture conditions. A growing body of recent research has shown efficient cell fate reprogramming by forced expression of single or multiple transcription factors. Here, we review transcription factor-directed differentiation methods of PSCs toward neural, muscle, liver, and pancreatic endocrine cells. Potential applications and limitations are also discussed in order to establish future directions of this technique for therapeutic purposes.