• Molecules and Cells
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• 제39권4호
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• pp.358-366
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• 2016

The digestive system is gaining interest as a major regulator of various functions including immune defense, nutrient accumulation, and regulation of feeding behavior, aside from its conventional function as a digestive organ. The Drosophila midgut epithelium is completely renewed every 1-2 weeks due to differentiation of pluripotent intestinal stem cells in the midgut. Intestinal stem cells constantly divide and differentiate into enterocytes that secrete digestive enzymes and absorb nutrients, or enteroendocrine cells that secrete regulatory peptides. Regulatory peptides have important roles in development and metabolism, but study has mainly focused on expression and functions in the nervous system, and not much is known about the roles in endocrine functions of enteroendocrine cells. We systemically examined the expression of 45 regulatory peptide genes in the Drosophila midgut, and verified that at least 10 genes are expressed in the midgut enteroendocrine cells through RT-PCR, in situ hybridization, antisera, and 25 regulatory peptide-GAL transgenes. The Drosophila midgut is highly compartmentalized, and individual peptides in enteroendocrine cells were observed to express in specific regions of the midgut. We also confirmed that some peptides expressed in the same region of the midgut are expressed in mutually exclusive enteroendocrine cells. These results indicate that the midgut enteroendocrine cells are functionally differentiated into different subgroups. Through this study, we have established a basis to study regulatory peptide functions in enteroendocrine cells as well as the complex organization of enteroendocrine cells in the Drosophila midgut.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.402-402
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• 2005

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2005년도 제48차 춘계 학술대회
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• pp.113-113
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• 2005

• Molecules and Cells
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• 제41권11호
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• pp.971-978
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• 2018

The stem cell factor (SCF)/c-KIT axis plays an important role in the hematopoietic differentiation of human pluripotent stem cells (hPSCs), but its regulatory mechanisms involving microRNAs (miRs) are not fully elucidated. Here, we demonstrated that supplementation with SCF increases the hematopoietic differentiation of hPSCs via the interaction with its receptor tyrosine kinase c-KIT, which is modulated by miR-221 and miR-222. c-KIT is comparably expressed in undifferentiated human embryonic and induced pluripotent stem cells. The inhibition of SCF signaling via treatment with a c-KIT antagonist (imatinib) during hPSC-derived hematopoiesis resulted in reductions in the yield and multi-lineage potential of hematopoietic progenitors. We found that the transcript levels of miR-221 and miR-222 targeting c-KIT were significantly lower in the pluripotent state than they were in terminally differentiated somatic cells. Furthermore, suppression of miR-221 and miR-222 in undifferentiated hPSC cultures induced more hematopoiesis by increasing c-KIT expression. Collectively, our data implied that the modulation of c-KIT by miRs may provide further potential strategies to expedite the generation of functional blood cells for therapeutic approaches and the study of the cellular machinery related to hematologic malignant diseases such as leukemia.

• Animal Bioscience
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• 제36권2호
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• pp.295-306
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• 2023

Objective: Inhibiting the p38 mitogen-activated protein kinase (MAPK) signaling pathway delays differentiation and increases proliferation of muscle stem cells in most species. Here, we aimed to investigate the effect of p38 inhibitor (p38i) treatment on the proliferation and differentiation of chicken muscle stem cells. Methods: Chicken muscle stem cells were collected from the muscle tissues of Hy-line Brown chicken embryos at embryonic day 18, then isolated by the preplating method. Cells were cultured for 4 days in growth medium supplemented with dimethyl sulfoxide or 1, 10, 20 μM of p38i, then subcultured for up to 4 passages. Differentiation was induced for 3 days with differentiation medium. Each treatment was replicated 3 times. Results: The proliferation and mRNA expression of paired box 7 gene and myogenic factor 5 gene, as well as the mRNA expression of myogenic differentiation marker gene myogenin were significantly higher in p38i-treated cultures than in control (p<0.05), but immunofluorescence staining and mRNA expression of myosin heavy chain (MHC) were not significantly different between the two groups. Oil red O staining of accumulated lipid droplets in differentiated cell cultures revealed a higher lipid density in p38i-treated cultures than in control; however, the expression of the adipogenic marker gene peroxisome proliferator activated receptor gamma was not significantly different between the two groups. Conclusion: p38 inhibition in chicken muscle stem cells improves cell proliferation, but the effects on myogenic differentiation and lipid accumulation require additional analysis. Further studies are needed on the chicken p38-MAPK pathway to understand the muscle and fat development mechanism.

• Biomolecules & Therapeutics
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• 제32권1호
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• pp.65-76
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• 2024

Bortezomib (BTZ) is a proteasome inhibitor used to treat multiple myeloma (MM). However, the induction of peripheral neuropathy is one of the major concerns in using BTZ to treat MM. In the current study, we have explored the effects of BTZ (0.01-5 nM) on rat neural stem cells (NSCs). BTZ (5 nM) induced cell death; however, the percentage of neurons was increased in the presence of mitogens. BTZ reduced the B-cell lymphoma 2 (Bcl-2)/Bcl-2 associated X protein ratio in proliferating NSCs and differentiated cells. Inhibition of βIII-tubulin (TUBB3) degradation was observed, but not inhibition of glial fibrillary acidic protein degradation, and a potential PEST sequence was solely found in TUBB3. In the presence of growth factors, BTZ increased cAMP response element-binding protein (CREB) phosphorylation, brain-derived neurotrophic factor (Bdnf) transcription, BDNF expression, and Tubb3 transcription in NSCs. However, in the neuroblastoma cell line, SH-SY5Y, BTZ (1-20 nM) only increased cell death without increasing CREB phosphorylation, Bdnf transcription, or TUBB3 induction. These results suggest that although BTZ induces cell death, it activates neurogenic signals and induces neurogenesis in NSCs.

• Journal of Microbiology
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• 제45권6호
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• pp.547-552
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• 2007

Previously, we generated monoclonal antibodies (MAbs) that bound to the surface of human embryonic stem cells (hESCs) in an attempt to discover new hESC-specific surface markers. In this study, MAb 47-235 (IgG1, ${\kappa}$) was selected for further characterization. The MAb bound to the surface of undifferentiated hESCs but did not bind to mouse ESCs or mouse embryonic fibroblast cells in flow cytometric analysis. The antibody immunoprecipitated a 47 kDa protein from the lysates of cell surface-biotinylated hESCs. Identification of the protein by quadrupole time of flight tandem mass spectrometry revealed that 47-235 binds to Ag 243-5 protein of Mycoplasma arginini. BM-Cyclin treatment of the hESCs that reacted with 47-235 resulted in loss of mycoplasma DNA and the reactivity to 47-235. Nevertheless, the hESCs that were reactive to 47-235 maintained self-renewal and pluripotency and thus could be differentiated into three embryonic germ layers.

• 한국발생생물학회지:발생과생식
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• 제14권4호
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• pp.233-241
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• 2010

사람의지방줄기세포는지방조직내에존재하는 줄기세포로 얻기 쉽고, 골수줄기세포와 유사한 특징을 가지고 있다. 그러나 지방을 추출하는 과정, 공여자의 나이, 체질량, 추출 부위에 따라 세포의 특성이 달라지며, 이질적인 세포군을 얻게 된다. 따라서 본 연구에서는 허벅지 지방에서 유래한 줄기세포 특성 분석 및 중배엽, 내배엽성 세포로의 분화능을 알아보았다. 허벅지 유래 줄기세포는 골수줄기세포와 유사한 섬유아세포와 유사한 모양을 보였으며, 체외에서 56.5번의 분열을 하였고, 약 $5{\times}10^{22}$개의 세포를 얻을 수 있었다. 이들은 SCF, Oct4, nanog, vimentin, CK18, FGF5, NCAM, Pax6, BMP4, HNF4a, nestin, GATA4, HLA-ABC, HLA-DR과 같은 유전자를 발현하였으며, Oct4, Thy-1, FSP, vWF, vimentin, desmin, CK18, CD54, CD4, CD106, CD31, a-SMA, HLA-ABC 등과 같은 단백질을 발현하였다. 또한 이들은 지방, 골, 연골 세포와 같은 중배엽성 세포로 분화하였고, 더욱이 인슐린 분비세포와 같은 내배엽성 세포로도 분화하였다. 결론적으로, 사람의 허벅지 유래 줄기세포는 골수 줄기세포와 유사하게 체외에서 증식이 가능하였으며, 유전자 및 단백질 발현 패턴을 가지고 있었으며, 다양한 세포로 분화 가능하였다. 이러한 결과로 미루어 보아 허벅지 지방유래 줄기세포는 골수 줄기세포를 대체할 수 있는 세포치료제의 재료가 될 수 있을 것으로 사료된다.

• Nutrition Research and Practice
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• 제4권6호
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• pp.455-461
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• 2010

The tumor microenvironment, particularly sufficient nutrition and oxygen supply, is important for tumor cell survival. Nutrition deprivation causes cancer cell death. Since apoptosis is a major mechanism of neuronal loss, we explored neuronal apoptosis in various microenvironment conditions employing neuroblastoma (NB) cells. To investigate the effects of tumor malignancy and differentiation on apoptosis, the cells were exposed to poor microenvironments characterized as serum-free, low-glucose, and hypoxia. Incubation of the cells in serum-free and low-glucose environments significantly increased apoptosis in less malignant and more differentiated N-type IMR32 cells, whereas more malignant and less differentiated I-type BE(2)C cells were not affected by those treatments. In contrast, hypoxia (1 % $O_2$) did not affect apoptosis despite cell malignancy. It is suggested that DLK1 constitutes an important stem cell pathway for regulating self-renewal, clonogenicity, and tumorigenicity. This raises questions about the role of DLK1 in the cellular resistance of cancer cells under poor microenvironments, which cancer cells normally encounter. In the present study, DLK1 overexpression resulted in marked protection from apoptosis induced by nutrient deprivation. This in vitro model demonstrated that increasing severity of nutrition deprivation and knock-down of DLK1 caused greater apoptotic death, which could be a useful strategy for targeted therapies in fighting NB as well as for evaluating how nutrient deprived cells respond to therapeutic manipulation.

• 한국동물생명공학회지
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• 제34권2호
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• pp.93-99
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• 2019

Telomeres are known as a specialized region in the end of chromosomes to protect DNA destruction, but their lengths are shortened by repetition of cell division. This telomere shortening can be preserved or be elongated by telomerase and TERT expression. Although a certain condition in the cells may affect to the cellular and molecular characteristics, the effect of differentiation induction to telomere length and telomerase activity in mesenchymal stem cells (MSCs) has been less studied. Therefore, the present study aimed to uncover periodical alterations of telomere length, telomerase activity and TERT expression in the dental pulp-derived MSCs (DP-MSCs) under condition of differentiation inductions into adipocytes and osteoblasts on a weekly basis up to 3 weeks. Shortening of telomere was significantly (p < 0.05) identified from early-middle stages of both differentiations in comparison with undifferentiated DP-MSCs by non-radioactive chemiluminescent assay and qRT-PCR method. Telomere length in undifferentiated DP-MSCs was 10.5 kb, but the late stage of differentiated DP-MSCs which can be regarded as the adult somatic cell exhibited 8.1-8.6 kb. Furthermore, the relative-quantitative telomerase repeat amplification protocol or western blotting presented significant (p < 0.05) decrease of telomerase activity since early stages of differentiations or TERT expression from middle stages of differentiations than undifferentiated state, respectively. Based on these results, it is supposed that shortened telomere length in differentiated DP-MSCs was remained along with prolonged differentiation durations, possibly due to weakened telomerase activity and TERT expression. We expect that the present study contributes on understanding differentiation mechanism of MSCs, and provides standardizing therapeutic strategies in clinical application of MSCs in the animal biotechnology.