• Molecules and Cells
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• 제43권12호
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• pp.1011-1022
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• 2020

Cell type specification is a delicate biological event in which every step is under tight regulation. From a molecular point of view, cell fate commitment begins with chromatin alteration, which kickstarts lineage-determining factors to initiate a series of genes required for cell specification. Several important neuronal differentiation factors have been identified from ectopic over-expression studies. However, there is scarce information on which DNA regions are modified during induced pluripotent stem cell (iPSC) to neuronal progenitor cell (NPC) differentiation, the cis regulatory factors that attach to these accessible regions, or the genes that are initially expressed. In this study, we identified the DNA accessible regions of iPSCs and NPCs via the Assay for Transposase-Accessible Chromatin sequencing (ATAC-seq). We identified which chromatin regions were modified after neuronal differentiation and found that the enhancer regions had more active histone modification changes than the promoters. Through motif enrichment analysis, we found that NEUROD1 controls iPSC differentiation to NPC by binding to the accessible regions of enhancers in cooperation with other factors such as the Hox proteins. Finally, by using Hi-C data, we categorized the genes that directly interacted with the enhancers under the control of NEUROD1 during iPSC to NPC differentiation.

• Molecules and Cells
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• 제40권7호
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• pp.485-494
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• 2017

Oleanolic acid (OA) has neurotrophic effects on neurons, although its use as a neurological drug requires further research. In the present study, we investigated the effects of OA and OA derivatives on the neuronal differentiation of rat hippocampal neural progenitor cells. In addition, we investigated whether the class II histone deacetylase (HDAC) 5 mediates the gene expression induced by OA. We found that OA and OA derivatives induced the formation of neurite spines and the expression of synapse-related molecules. OA and OA derivatives stimulated HDAC5 phosphorylation, and concurrently the nuclear export of HDCA5 and the expression of HDAC5 target genes, indicating that OA and OA derivatives induce neural differentiation and synapse formation via a pathway that involves HDAC5 phosphorylation.

• The Korean Journal of Physiology and Pharmacology
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• 제16권4호
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• pp.281-285
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• 2012

A previous animal study has shown the effects of erythropoietin (EPO) and its non-erythropoietic carbamylated derivative (CEPO) on neurogenesis in the dentate gyrus. In the present study, we sought to investigate the effect of EPO on adult hippocampal neurogenesis, and to compare the ability of EPO and CEPO promoting dendrite elongation in cultured hippocampal neural progenitor cells. Two-month-old male BALB/c mice were given daily injections of EPO (5 U/g) for seven days and were sacrificed 12 hours after the final injection. Proliferation assays demonstrated that EPO treatment increased the density of bromodeoxyuridine (BrdU)-labeled cells in the subgranular zone (SGZ) compared to that in vehicle-treated controls. Functional differentiation studies using dissociated hippocampal cultures revealed that EPO treatment also increased the number of double-labeled BrdU/microtubulea-ssociated protein 2 (MAP2) neurons compared to those in vehicle-treated controls. Both EPO and CEPO treatment significantly increased the length of neurites and spine density in MAP2(+) cells. In summary, these results provide evidences that EPO and CEPO promote adult hippocampal neurogenesis and neuronal differentiation. These suggest that EPO and CEPO could be a good candidate for treating neuropsychiatric disorders such as depression and anxiety associated with neuronal atrophy and reduced hippocampal neurogenesis.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.71-71
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• 2003

Human umbilical cord blood cells(HUCBC) are rich in mesenchymal progenitor cells, endothelial cell precursors and hematopoietic cells. HUCBC have been used as a source of transplantable stem and progenitor cells. However, little is known about survival and development of HUCBC transplantation in the CNS. Estrogen has a neuroprotective potential against oxidative stress-induced cell death so has an effect on reducing infarct size of ischemic brain. We investigated the potential use of HUCBC as donor cells and tested whether estrogen mediates intravenously infused HUCBC enter and survive in ischemic brain. PKH26 labeled mononuclear fraction of HUCBC were injected into the tail vein of ischemic OVX rat brain with or without $17\beta$-estradiol valerate(EV). Under fluorescence microscopy, labeled cells were observed in the brain section. Significantly more cells were found in the ischemic brain than in the non-ischemic brain. HUCBC transplanted into ischemic brain could migrate and survive. Some of cells have shown neuronal like cells in hippocampus, striatum and cortex tissues. These result suggest that estrogen reduces ischemic damage and increases the migration of human umbilical cord blood cells. This Study was supported by the Korea Science and Engineering Foundation(KOSEF) though the Biohealth Products Research Center(BPRC), Inje University, Korea.

• Biomolecules & Therapeutics
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• 제31권3호
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• pp.264-275
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• 2023

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by tremors, bradykinesia, and rigidity. PD is caused by loss of dopaminergic (DA) neurons in the midbrain substantia nigra (SN) and therefore, replenishment of DA neurons via stem cell-based therapy is a potential treatment option. Astrocytes are the most abundant non-neuronal cells in the central nervous system and are promising candidates for reprogramming into neuronal cells because they share a common origin with neurons. The ability of neural progenitor cells (NPCs) to proliferate and differentiate may overcome the limitations of the reduced viability and function of transplanted cells after cell replacement therapy. Achaete-scute complex homolog-like 1 (Ascl1) is a well-known neuronal-specific factor that induces various cell types such as human and mouse astrocytes and fibroblasts to differentiate into neurons. Nurr1 is involved in the differentiation and maintenance of DA neurons, and decreased Nurr1 expression is known to be a major risk factor for PD. Previous studies have shown that direct conversion of astrocytes into DA neurons and NPCs can be induced by overexpression of Ascl1 and Nurr1 and additional transcription factors genes such as superoxide dismutase 1 and SRY-box 2. Here, we demonstrate that astrocytes isolated from the ventral midbrain, the origin of SN DA neurons, can be effectively converted into DA neurons and NPCs with enhanced viability. In addition, when these NPCs are inducted to differentiate, they exhibit key characteristics of DA neurons. Thus, direct conversion of midbrain astrocytes is a possible cell therapy strategy to treat neurodegenerative diseases.

• Archives of Plastic Surgery
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• 제33권2호
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• pp.205-212
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• 2006

Using adipose derived stem cells(ASCs), neurogenic differentiation was induced in a mono layered culture medium containing neuronal induction agents. Cells differentiated to the neuronal cells were observed with a inverted microscope and immunofluorecent study. We made a 15 mm long defect in the sciatic nerve of 14 rats and connected a silicone tube to the defect. Then, we mixed neuronal progenitor cells differentiated from ASCs with collagen gel and grafted them to a group of rats(experimental group) and grafted only collagen gel into another group(control group). In 4 and 8 weeks after the graft, histological observation was made. According to the result, the number and diameter of myelinated axons were significantly increased in the experimental group. In addition, the nerve conduction velocity was improved more in the experimental group and neovascularity also increased. Moreover, reaction with S100 and p75 was observed in regenerated nerves in the experimental group, suggesting that the grafted cells were differentiated into supportive cells such as Schwann's cells. In conclusion, this research proved that ASCs can multiply and differentiate into neuronal cells. If they are grafted into nerve defects, the grafted cells are differ entiated into supportive cells such as Schwann's cells and thus contribute to nerve regeneration. Accordingly, the use of adipose tissue obtained easily without the limitation of donor site can be greatly helpful in treating peripheral nerve defects.

• Biomolecules & Therapeutics
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• 제26권5호
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• pp.439-445
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• 2018

T-type calcium channels are low voltage-activated calcium channels that evoke small and transient calcium currents. Recently, T-type calcium channels have been implicated in neurodevelopmental disorders such as autism spectrum disorder and neural tube defects. However, their function during embryonic development is largely unknown. Here, we investigated the function and expression of T-type calcium channels in embryonic neural progenitor cells (NPCs). First, we compared the expression of T-type calcium channel subtypes (CaV3.1, 3.2, and 3.3) in NPCs and differentiated neural cells (neurons and astrocytes). We detected all subtypes in neurons but not in astrocytes. In NPCs, CaV3.1 was the dominant subtype, whereas CaV3.2 was weakly expressed, and CaV3.3 was not detected. Next, we determined CaV3.1 expression levels in the cortex during early brain development. Expression levels of CaV3.1 in the embryonic period were transiently decreased during the perinatal period and increased at postnatal day 11. We then pharmacologically blocked T-type calcium channels to determine the effects in neuronal cells. The blockade of T-type calcium channels reduced cell viability, and induced apoptotic cell death in NPCs but not in differentiated astrocytes. Furthermore, blocking T-type calcium channels rapidly reduced AKT-phosphorylation (Ser473) and $GSK3{\beta}$-phosphorylation (Ser9). Our results suggest that T-type calcium channels play essential roles in maintaining NPC viability, and T-type calcium channel blockers are toxic to embryonic neural cells, and may potentially be responsible for neurodevelopmental disorders.

• 생명과학회지
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• 제23권12호
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• pp.1532-1540
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• 2013

Tbr2는 T-box family 전사인자의 하나로써 뇌의 발달, 전구세포의 증식, 그리고 CD8+ T 세포와 자연살상세포의 분화와 기능에 중요한 역할을 하는 것으로 알려져 있다. 본 연구는 마우스에서 pilocarpine을 이용하여 경련중첩증을 유도한 후 나타나는 병리기전에 Tbr2의 연관성을 확인하였다. 경련중첩증은 해마의 CA3, hilus 그리고 조롱박피질 등에서 뚜렷한 신경세포의 손상을 유발하였다. 흥미롭게도 Tbr2를 이용한 조직 염색에서 경련중첩증 2일 후에 CA3와 조롱박피질에서 면역반응성이 뚜렷하게 증가하는 것을 관찰하였다. 또한 CA3와 조롱박피질에서 Tbr2를 발현하는 세포는 미세아교세포와 단핵구, CD8+ T세포 또는 자연살상세포 등 백혈구의 표지물질인 CD11b 와 이중염색되는 것을 발견하였다. Tbr2와 CD11b에 동시에 염색된 세포는 아메바 모양의 형태를 갖추고 있는 것을 발견하였다. 게다가 혈관 내피세포에서 발혈되는 platelet endothelial cell adhesion molecule-1(PECAM-1)과 이중 염색한 결과 Tbr2를 발현하는 세포가 CA3 지역의 혈관내에 다량 존재하는 것을 확인하였다. 이상의 결과를 종합할 때 Tbr2를 발현하는 세포는 뇌 조직으로 이주하는 백혈구일 가능성이 높음을 보여준다. 이러한 결과는 경련중첩증에 따른 신경병리기전에 Tbr2가 관여할 가능성이 높음을 처음으로 제시하였다.

• 생명과학회지
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• 제28권12호
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• pp.1397-1405
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• 2018

미토콘드리아는 세포안에서 에너지 공급, 칼슘 이온 저장, 활성산소 생성, 세포 자살과 같은 다양한 기능을 수행한다. 이러한 기능을 통해, 미토콘드리아는 줄기세포의 유지, 증식, 그리고 분화에 관여한다. 뇌에서 뇌실 하 영역(subventricular zone, SVZ)에는 일평생 새로운 신경세포를 생성하는 신경줄기세포(neural stem cell, NSC)가 존재한다. 하지만, SVZ NSCs에서 미토콘드리아의 역할에 대한 연구는 많이 알려져 있지 않다. 이번 연구에서 우리는 미토콘드리아의 complex I 저해제인 rotenone이 SVZ NSCs의 증식과 분화를 다른 방식으로 방해한다는 것을 보여주었다. 증식 중인 신경줄기세포에서, rotenone은 세포분열을 감소시켰는데, 이때 세포분열은 히스톤 H3에 인산기가 붙어있는 지를 측정하여 확인하였다. Rotenone을 50 nM 농도로 증식 중인 신경줄기세포에 처리했을 때, 세포사멸은 발생하지 않았다. 한편, 분화 중인 신경줄기세포에 rotenone을 처리한 경우, 신경세포와 희소 돌기아교 세포(oligodendrocyte)으로의 분화가 억제되었고, glial fibrillary acidic protein (GFAP)를 발현하는 성상세포(astrocyte)에는 영향이 없었다. 흥미롭게도, 4-6일 동안의 분화 과정 동안 rotenone이 처리된 신경줄기세포에서 대조군 보다 더 많은 세포 수가 관찰 되었는데, 이는 증식 과정 중의 rotenone의 효과와 다른 것이다. 이에, 우리는 rotenone이 세포 자살은 감소시켰으나, 세포 분열에는 영향을 끼치지 않았음을 관찰하였다. 세포 자살의 경우는 cleaved caspase-3를 측정함으로써 확인하였다. 이러한 결과들은 SVZ 신경줄기세포의 증식과 분화 모두에 제대로 작동하는 미토콘드리아가 있어야 함을 제안하고 있다. 게다가, 이러한 과정에서 미토콘드리아는 세포 분열과 세포자살에 관여할 수도 있을 것이다.