• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제36권1호
• /
• pp.7-15
• /
• 2010

Complex human tissues harbor stem cells and precursor cells, which are responsible for tissue development or repair. Recently, dental tissues such as dental pulp, periodontal ligament (PDL), dental follicle have been identified as easily accessible sources of undifferentiated cells. These tissues contain mesenchymal stem cells that can be differentiate into bone, cartilage, fat or muscle by exposing them to specific growth conditions. In this study, the authors procured the stem cell from pulp, PDL, and dental follicle and differentiate them into osteoblast and examine the bone induction capacity. Dental pulp stem cell (DPSC), periodontal ligament stem cell (PDLSC), and dental follicle precursor cell (DFPC) were obtained from human 3rd molar and cultured. Each cell was analyzed for presence of stem cell by fluorescence activated cell sorter (FACs) against CD44, CD105 and CD34, CD45. Each stem cell was cultured, expanded and grown in an osteogenic culture medium to allow formation of a layer of extracellular bone matrix. Osteogenic pathway was checked by alizarin red staining, alkaline phosphatase (ALP) activity test and RT-PCR for ALP and osteocalcin (OCN) gene expression. According to results from FACs, mesenchymal stem cell existed in pulp, PDL, and dental follicle. As culturing with bone differentiation medium, stem cells were differentiated to osteoblast like cell. Compare with stem cell from pulp, PDL and dental follicle-originated stem cell has more osteogenic effect and it was assumed that the character of donor cell was able to affect on differential potency of stem cell. From this article, we are able to verify the pulp, PDL, and dental follicle from extracted tooth, and these can be a source of osteoblast and stem cell for tissue engineering.

• Molecules and Cells
• /
• 제25권4호
• /
• pp.487-493
• /
• 2008

HoxB4 has been shown to enhance hematopoietic engraftment by hematopoietic stem cells (HSC) from differentiating mouse embryonic stem cell (mESC) cultures. Here we examined the effect of ectopic expression of HoxB4 in differentiated human embryonic stem cells (hESCs). Stable HoxB4-expressing hESCs were established by lentiviral transduction, and the forced expression of HoxB4 did not affect stem cell features. HoxB4-expressing hESC-derived CD34+ cells generated higher numbers of erythroid and blast-like colonies than controls. The number of CD34+ cells increased but CD45+ and KDR+ cell numbers were not significantly affected. When the hESC derived CD34+ cells were transplanted into $NOD/SCID{\beta}2m-/-$ mice, the ectopic expression of HoxB4 did not alter their repopulating capacity. Our findings show that overexpression of HoxB4 in differentiating hESCs increases hematopoietic colony formation and hematopoietic cell formation in vitro, but does not affect in vivo repopulation in adult mice hosts.

• BMB Reports
• /
• 제55권7호
• /
• pp.336-341
• /
• 2022

Narrowing of arteries supplying blood to the limbs provokes critical hindlimb ischemia (CLI). Although CLI results in irreversible sequelae, such as amputation, few therapeutic options induce the formation of new functional blood vessels. Based on the proangiogenic potentials of stem cells, in this study, it was examined whether a combination of dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs) could result in enhanced therapeutic effects of stem cells for CLI compared with those of DPSCs or HUVECs alone. The DPSCs+ HUVECs combination therapy resulted in significantly higher blood flow and lower ischemia damage than DPSCs or HUVECs alone. The improved therapeutic effects in the DPSCs+ HUVECs group were accompanied by a significantly higher number of microvessels in the ischemic tissue than in the other groups. In vitro proliferation and tube formation assay showed that VEGF in the conditioned media of DPSCs induced proliferation and vessel-like tube formation of HUVECs. Altogether, our results demonstrated that the combination of DPSCs and HUVECs had significantly better therapeutic effects on CLI via VEGF-mediated crosstalk. This combinational strategy could be used to develop novel clinical protocols for CLI proangiogenic regenerative treatments.

• Molecules and Cells
• /
• 제46권8호
• /
• pp.476-485
• /
• 2023

Gastric cancer stem-like cells (GCSCs) possess stem cell properties, such as self-renewal and tumorigenicity, which are known to induce high chemoresistance and metastasis. These characteristics of GCSCs are further enhanced by autophagy, worsening the prognosis of patients. Currently, the mechanisms involved in the induction of stemness in GCSCs during autophagy remain unclear. In this study, we compared the cellular responses of GCSCs with those of gastric cancer intestinal cells (GCICs) whose stemness is not induced by autophagy. In response to glucose starvation, the levels of β-catenin and stemness-related genes were upregulated in GCSCs, while the levels of β-catenin declined in GCICs. The pattern of deubiquitinase ubiquitin C-terminal hydrolase-L3 (UCH-L3) expression in GCSCs and GCICs was similar to that of β-catenin expression depending on glucose deprivation. We also observed that inhibition of UCH-L3 activity reduced β-catenin protein levels. The interaction between UCH-L3 and β-catenin proteins was confirmed, and it reduced the ubiquitination of β-catenin. Our results suggest that UCH-L3 induces the stabilization of β-catenin, which is required to promote stemness during autophagy activation. Also, UCH-L3 expression was regulated by c-Fos, and the levels of c-Fos increased in response to autophagy activation. In summary, our findings suggest that the inhibition of UCH-L3 during nutrient deprivation could suppress stress resistance of GCSCs and increase the survival rates of gastric cancer patients.

• 한국발생생물학회지:발생과생식
• /
• 제13권3호
• /
• pp.173-181
• /
• 2009

One of the most extensively studied populations of multipotent adult stem cells are mesenchymal stem cells (MSCs). MSCs derived from the human umbilical cord vein (HUC-MSCs) are morphologically and immunophenotypically similar to MSCs isolated from bone marrow. HUC-MSCs are multipotent stem cells, differ from hematopoietic stem cells and can be differentiated into neural cells. Since neural tissue has limited intrinsic capacity of repair after injury, the identification of alternate sources of neural stem cells has broad clinical potential. We isolated mesenchymal-like stem cells from the human umbilical cord vein, and studied transdifferentiation-promoting conditions in neural cells. Dopaminergic neuronal differentiation of HUC-MSCs was also studied. Neural differentiation was induced by adding bFGF, EGF, dimethyl sulfoxide (DMSO) and butylated hydroxyanisole (BHA) in N2 medium and N2 supplement. The immunoreactive cells for $\beta$-tubulin III, a neuron-specific marker, GFAP, an astrocyte marker, or Gal-C, an oligodendrocyte marker, were found. HUC-MSCs treated with bFGF, SHH and FGF8 were differentiated into dopaminergic neurons that were immunopositive for tyrosine hydroxylase (TH) antibody. HUC-MSCs treated with DMSO and BHA rapidly showed the morphology of multipolar neurons. Both immunocytochemistry and RT-PCR analysis indicated that the expression of a number of neural markers including NeuroD1, $\beta$-tubulin III, GFAP and nestin was markedly elevated during this acute differentiation. While the stem cell markers such as SCF, C-kit, and Stat-3 were not expressed after neural differentiation, we confirmed the differentiation of dopaminergic neurons by TH/$\beta$-tubulin III positive cells. In conclusion, HUC-MSCs can be differentiated into dopaminergic neurons and these findings suggest that HUC-MSCs are alternative cell source of therapeutic treatment for neurodegenerative diseases.

• 생명과학회지
• /
• 제17권8호통권88호
• /
• pp.1039-1045
• /
• 2007

다형성 교모세포종은 뇌종양 가운데 가장 빈번하게 발병하는 악성종양이다. 다형성 교모세포종에 종양 줄기세포가 존재한다는 보고가 있음에도 불구하고, 항암제 내성과 종양 줄기세포 사이의 상호 연관성에 관한 연구는 아직 미비한 실정이다. 본 연구에서 다형성 교모세포종 세포주 A172 및 뇌종양 환자로부터 확립한 GBM2에 1,3-bis(2 -chloroethyl)-1-nitrosourea (BiCNU)를 처리시 극소량의 세포군만이 생존하며, 이들 생존 세포군은 BiCNU 재처리에 내성을 나타내는 것으로 조사되었다. 또한 이 다형성 교모세포종 유래 BiCNU-내성세포군의 Erk 및 Akt 인산화 활성이 증가되었으며, CD133 줄기세포 표지인자를 발현하는 세포가 다량 존재하였다. 이와 아울러, 다형성 교모세포종 유래 BiCNU-내성세포를 severe combined immuno-deficient (SCID) mouse brain에 이식하였을 때 암이 형성되는 것을 관찰할 수 있었다. 이와 같은 결과는 다형성 교모세포종 유래 BiCNU-내성세포가 종양줄기세포의 능력을 가지는 것으로 생각된다. 따라서 이상의 결과는 다형성 교모세포종에 존재하는 종양줄기세포가 항암제 내성에 관여 한다는 중요한 단서를 제공해줄 수 있을 것으로 사료된다.

• Clinical and Experimental Reproductive Medicine
• /
• 제42권2호
• /
• pp.33-44
• /
• 2015

The generation of artificial gametes is a real challenge for the scientific community today. In vitro development of human eggs and sperm will pave the way for the understanding of the complex process of human gametogenesis and will provide with human gametes for the study of infertility and the onset of some inherited disorders. However, the great promise of artificial gametes resides in their future application on reproductive treatments for all these people wishing to have genetically related children and for which gamete donation is now their unique option of parenthood. This is the case of infertile patients devoid of suitable gametes, same sex couples, singles and those fertile couples in a high risk of transmitting serious diseases to their progeny. In the search of the best method to obtain artificial gametes, many researchers have successfully obtained human germ cell-like cells from stem cells at different stages of differentiation. In the near future, this field will evolve to new methods providing not only viable but also functional and safe artificial germ cells. These artificial sperm and eggs should be able to recapitulate all the genetic and epigenetic processes needed for the correct gametogenesis, fertilization and embryogenesis leading to the birth of a healthy and fertile newborn.

• Clinical and Experimental Reproductive Medicine
• /
• 제37권2호
• /
• pp.99-113
• /
• 2010

목 적: 최근 다능성을 가진 극소형 줄기세포가 생쥐와 인간에서 발견된다고 보고되었다. 이 연구의 목적은 극소형 추정줄기세포들이 인간 자궁내막에 존재하는지, 그리고 이 세포들이 줄기세포의 고유 특성들과 줄기세포 표지자들을 발현시키는지 확인하기 위함이다. 연구방법: 자궁내막조직검사로부터 채취한 여성 5명의 자궁내막세포를 2주 동안 배양하였으며, alkaline phosphatase, OCT-4, CXCR4 면역화학염색을 통해 줄기세포 표지자 발현 여부를 확인하였다. 이후 percoll density gradient method 방법으로 극소형 추정줄기세포들을 분리하여 배양하였으며, 또한 극소형 추정줄기세포들과 그 유래의 세포들이 OCT-4와 CXCR4를 발현시키는지 확인하였다. 결 과: $3{\mu}m$ 미만의 극소형 추정줄기세포들과 5~15 ${\mu}m$의 과다염색질 원형세포들로 구성된 군집들이 모든 여성의 자궁내막세포에서 발견되었으며, alkaline phosphatase, OCT-4 및 CXCR4를 강하게 발현시켰다. Percoll을 이용하여 극소형 추정줄기세포들을 분리 배양한 결과, 극소형 추정줄기세포들은 자가재생, 배아체양 형성, 군집 형성, 분화 가소성과 같은 줄기세포의 형태학적 및 기능적인 특성들을 나타내었다. 극소형 추정줄기세포들은 세포간 응집 혹은 세포융합을 통하여 약 5~15 ${\mu}m$ 과다염색질 원형세포들과 약 10~20 ${\mu}m$ 구형세포들을 점진적으로 형성시켰다. 이후이 세포들은 섬유아세포 유사세포, 신경유사세포, 혈관내피유사세포를 포함하는 다양한 세포로 분화하였다. 또한 극소형 추정줄기세포들과 극소형 추정줄기세포에서 유래한 세포들은 흔히 OCT-4와 CXCR4를 강하게 발현시켰다. 결 론: 3 ${\mu}m$ 미만의 극소형 추정줄기세포들과 극소형 추정줄기세포에서 유래한 세포들이 인간 자궁내막에서 발견되며, 이 세포들은 줄기세포의 고유 특성들과 줄기세포 표지자인 alkaline phosphatase, OCT-4, CXCR4를 발현시킨다.

• BMB Reports
• /
• 제53권8호
• /
• pp.425-430
• /
• 2020

Tumor necrosis factor-inducible gene 6 protein (TSG-6) is a cytokine secreted by mesenchymal stem cells (MSCs) and regulates MSC stemness. We previously reported that TSG-6 changes primary human hepatic stellate cells (pHSCs) into stem-like cells by activating yes-associated protein-1 (YAP-1). However, the molecular mechanism behind the reprogramming action of TSG-6 in pHSCs remains unknown. Cluster of differentiation 44 (CD44) is a transmembrane protein that has multiple functions depending on the ligand it is binding, and it is involved in various signaling pathways, including the Wnt/β-catenin pathway. Given that β-catenin influences stemness and acts downstream of CD44, we hypothesized that TSG-6 interacts with the CD44 receptor and stimulates β-catenin to activate YAP-1 during TSG-6-mediated transdifferentiation of HSCs. Immunoprecipitation assays showed the interaction of TSG-6 with CD44, and immunofluorescence staining analyses revealed the colocalization of TSG-6 and CD44 at the plasma membrane of TSG-6-treated pHSCs. In addition, TSG-6 treatment upregulated the inactive form of phosphorylated glycogen synthase kinase (GSK)-3β, which is a negative regulator of β-catenin, and promoted nuclear accumulation of active/nonphosphorylated β-catenin, eventually leading to the activation of YAP-1. However, CD44 suppression in pHSCs following CD44 siRNA treatment blocked the activation of β-catenin and YAP-1, which inhibited the transition of TSG-6-treated HSCs into stem-like cells. Therefore, these findings demonstrate that TSG-6 interacts with CD44 and activates β-catenin and YAP-1 during the conversion of TSG-6-treated pHSCs into stem-like cells, suggesting that this novel pathway is an effective therapeutic target for controlling liver disease.

• International Journal of Stem Cells
• /
• 제9권2호
• /
• pp.186-191
• /
• 2016

Background and Objectives: With the global demand for dairy protein for consumption growing annually, there has been increasing activity in the research field of dairy protein synthesis and production. From a manipulation perspective, it is more difficult to use live cattle for laboratory studies on the production of milk as well as of dairy protein such as casein, as compared with using laboratory animals like rodents. Therefore, we aimed to develop a mouse model of bovine mammary alveolar ducts for laboratory-scale studies. We studied the formation of the bovine mammary gland ductal structure by transplanting the MAC-T bovine alveolar cell line into mice. Methods and Results: MAC-T cells ($1{\times}10^7$) were suspended in Matrigel and injected into the dorsal tissue of 8-week-old male BALB/C nude mice. Histological analysis of tissue dissected from the MAC-T cell-transplanted mice after 6 weeks showed the typical morphology of the tubuloalveolar female gland, as well as glands made up of branching ducts that were surrounded by smooth muscle with small alveoli budding off the ducts. In addition, the epithelial markers CK14 and CK18 were expressed within the duct-like structure. Prolactin was detected in the duct interior in these CK14+ and CK18+ cells but not in the non-transplanted MAC-T cells. Conclusions: These results showed that duct-like tissue had been successfully formed after 6 weeks of transplantation of the CK14+ and CK18+ MAC-T cells into mice dorsal tissue. This mouse model will be a useful tool for further research on the bovine mammary gland.