• 한국독성학회:학술대회논문집
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• 한국독성학회 2006년도 추계학술대회
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• pp.55-64
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• 2006

The fetal central nervous system (CNS) is sensitive to diverse environmental factors, such as alcohol, heavy metals, irradiation, mycotoxins, neurotransmitters, and DNA damage, because a large number of processes occur during an extended period of development. Fetal neural damage is an important issue affecting the completion of normal CNS development. As many concepts about the brain development have been recently revealed, it is necessary to compare the mechanism of developmental abnormalities induced by extrinsic factors with the normal brain development. To clarify the mechanism of fetal CNS damage, we used one experimental model in which 5-azacytidine (5AZC), a DNA damaging and demethylating agent, was injected to the dams of rodents to damage the fetal brain. 5AzC induced cell death (apoptosis)and cell cycle arrest in the fetal brain, and it lead to microencephaly in the neonatal brain. We investigated the mechanism of apoptosis and cell cycle arrest in the neural progenitor cells in detail, and demonstrated that various cell cycle regulators were changed in response to DNA damage. p53, the guardian of genome, played a main role in these processes. Further, using DNA microarray analysis, tile signal cascades of cell cycle regulation were clearly shown. Our results indicate that neural progenitor cells have the potential to repair the DNA damages via cell cyclearrest and to exclude highly affected cells through the apoptotic process. If the stimulus and subsequent DNA damage are high, brain development proceeds abnormally and results in malformation in the neonatal brain. Although the mechanisms of fetal brain injury and features of brain malformation afterbirth have been well studied, the process between those stages is largely unknown. We hypothesized that the fetal CNS has the ability to repair itself post-injuring, and investigated the repair process after 5AZC-induced damage. Wefound that the damages were repaired by 60 h after the treatment and developmental processes continued. During the repair process, amoeboid microglial cells infiltrated in the brain tissue, some of which ingested apoptotic cells. The expressions of genes categorized to glial cells, inflammation, extracellular matrix, glycolysis, and neurogenesis were upregulated in the DNA microarray analysis. We show here that the developing brain has a capacity to repair the damage induced by the extrinsic stresses, including changing the expression of numerous genes and the induction of microglia to aid the repair process.

• Archives of Pharmacal Research
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• 제17권5호
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• pp.343-347
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• 1994

Effects of betaine on glutamate-induced neurotoxicity were examined on primary culturs of chicken embryonic brain cells and on rat cortical cultures. Betaine was found to attenuate glutamate-induced neurotoxicity both morphologically and biochemically. A 30 min exposure of chicken embryonic brain cells cultured for 12 days to 500 .mu.M glutamate produced wide-spread acute neuronal swelling and neurtic fragmentation. A 2-h pretreatment of cultured chicken embryonic brain cells with i mM betaine prior to a 30 min exposure to 500 , mu, M glutamate significantly raised the survival rate of neurons in the culture. When chicken embryonic brain cells were pretreated for 2 h with i mM betaine followed by exposure to 100 .mu.M glutamate for 42 h, lactate dehydrogenase levels within the cells remained at 62% of .mu.M untreated control values while glutamate-treated control fell to 0% lactate dehydrogenase. Betaine also exerted attenuating effects on N-methyl-D-asparte-, kainate-and quisqualate-induced neurotoxicity in a similar manner to that observed with glutamate. Similar neuroprotective effects of betaine with rat cortical cultures.

• Molecules and Cells
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• 제42권9호
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• pp.617-627
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• 2019

Brain organoids are an exciting new technology with the potential to significantly change our understanding of the development and disorders of the human brain. With step-by-step differentiation protocols, three-dimensional neural tissues are self-organized from pluripotent stem cells, and recapitulate the major millstones of human brain development in vitro. Recent studies have shown that brain organoids can mimic the spatiotemporal dynamicity of neurogenesis, the formation of regional neural circuitry, and the integration of glial cells into a neural network. This suggests that brain organoids could serve as a representative model system to study the human brain. In this review, we will overview the development of brain organoid technology, its current progress and applications, and future prospects of this technology.

• 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.

• Asian Pacific Journal of Cancer Prevention
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• 제16권12호
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• pp.4849-4852
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• 2015

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been investigated as an effective agent to treat various cancers. Cancer stem cells are resistant to TRAIL treatment, but the mechanism of TRAIL resistance remains unknown. In this study, brain cancer stem cells were isolated by CD133 magnetic sorting, and the number of CD133 positive cells detected by flow cytometry. The self-renewing capacity of brain cancer stem cells was examined by a neurosphere formation assay, and the percentage of cell death after TRAIL treatment was examined by an MTS assay. Expression of DR5, FADD, caspase 8 and BCL2 proteins was detected by western blot. The amount of CD133 positive cells was enriched to 71% after CD133 magnetic sorting. Brain cancer stem cell neurosphere formation was significantly increased after TRAIL treatment. TRAIL treatment also reduced the amount of viable cells and this decrease was inhibited by a caspase 8 inhibitor or by the pan-caspase inhibitor z-VAD (P<0.05). Brain cancer stem cells expressed lower levels caspase 8 protein and higher levels of BCL2 protein when compared with CD133 negative cells (P<0.05). Our data suggest that TRAIL resistance is related to overexpression of BCL2 and low expression of caspase 8 which limit activation of caspase 8 in brain cancer stem cells.

• BMB Reports
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• 제57권7호
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• pp.311-317
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• 2024

Brain organoid is a three-dimensional (3D) tissue derived from stem cells such as induced pluripotent stem cells (iPSCs) embryonic stem cells (ESCs) that reflect real human brain structure. It replicates the complexity and development of the human brain, enabling studies of the human brain in vitro. With emerging technologies, its application is various, including disease modeling and drug screening. A variety of experimental methods have been used to study structural and molecular characteristics of brain organoids. However, electrophysiological analysis is necessary to understand their functional characteristics and complexity. Although electrophysiological approaches have rapidly advanced for monolayered cells, there are some limitations in studying electrophysiological and neural network characteristics due to the lack of 3D characteristics. Herein, electrophysiological measurement and analytical methods related to neural complexity and 3D characteristics of brain organoids are reviewed. Overall, electrophysiological understanding of brain organoids allows us to overcome limitations of monolayer in vitro cell culture models, providing deep insights into the neural network complex of the real human brain and new ways of disease modeling.

• 한국수의병리학회지
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• 제3권2호
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• pp.73-76
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• 1999

The tissue distribution and cellular localization of viral antigen in the brain of aborted fetus with bovine viral diarrhea virus(BVDV) infection was studied; BVDV antigens was detected in spleen, kidney, lung, eyelid as well as brain. In the brain, the virus was recognized in neurons and non-neuronal cells in the cerebellum and cerebrum. Many cells in the superficial layer and occasional Purkinje cells had BVDV antigens. As well, BVDV was also found in the perivascular cells, vascular endothelial cells and smooth muscle cells in the vessels and neuroglial cells in the white matter. This finding suggests that BVD virus favors infect progenitor cells in the brain, notably in the superficial layer of cerebellum, and damage normal development of cerebellum, which leads to cerebellar hypoplasia.

• 대한수의학회지
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• 제40권3호
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• pp.431-437
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• 2000

The aim of this study was to evaluate the involvement of CPP32 (caspase-3), one of the death-related enzymes, in the course of experimental autoimmune encephalomyelitis (EAE). EAE was induced in Lewis rats immunized with an emulsion of rat spinal cord homogenate with complete Freunds adjuvant supplemented with Mycobacterium tuberculosis (H37Ra, 5mg/ml). The expression of CPP32 in the spinal cords of rats with EAE was studied. In normal rat spinal cords, CPP32 is constitutively, but weakly, expressed in neurons and some neuroglial cells. In the EAE spinal cords, many inflammatory cells were positive for CPP 32, and the majority of CPP32(+) cells were identified as ED1(+) macrophages. During this stage of EAE, the number of CPP32(+) cells in brain cells, including neurons and astrocytes, increased, and these cells also had increased CPP32 immunoreactivity. CPP32 immunor eactivity was not always matched with apoptosis of inflammatory cells in EAE lesions. We speculate that CPP32, which is constitutlvely expressed in brain cells, increases in response to neuroimmunological stimulation in both brain neuronal cells and inflammatory cells. The functional role of CPP32 in neuroimmunological disorders is discussed.

• The Korean Journal of Physiology and Pharmacology
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• 제15권6호
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• pp.327-332
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• 2011

It has been shown that some opium derivatives promote cell death via apoptosis. This study was designed to examine the influence of opium addiction on brain and liver cells apoptosis in male and female diabetic and non-diabetic Wistar rats. This experimental study was performed on normal, opium-addicted, diabetic and diabetic opium-addicted male and female rats. Apoptosis was evaluated by TUNEL and DNA fragmentation assays. Results of this study showed that apoptosis in opium-addicted and diabetic opium-addicted brain and liver cells were significantly higher than the both normal and diabetic rats. In addition, we found that apoptosis in brain cells of opium-addicted and diabetic opium-addicted male rats were significantly higher than opium-addicted and diabetic opium-addicted female, whereas apoptosis in liver cells of opium-addicted and diabetic opium-addicted female rats were significantly higher than opium-addicted and diabetic opium-addicted male. Overall, these results indicate that opium probably plays an important role in brain and liver cells apoptosis, therefore, leading neurotoxicity and hepatotoxicity. These findings also in away possibly means that male brain cells are more susceptible than female and interestingly liver of females are more sensitive than males in induction of apoptosis by opium.

• 생약학회지
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• 제27권4호
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• pp.350-353
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• 1996

The effects of acid hydrolysis product of Panax ginseng and MeOH extract of Euphorbia humifusa on the growth of human brain tumor cells were evaluated using U-373 MG human astrocytoma and SK-N-MC human neuroblastoma cells as model cellular systems. These plant extracts induced cytotoxicity in both cells in a dose-dependent manner. These cytotoxic effects were significantly inhibited by GSH, an antioxidant, in both cells. BAPTA/AM, an intracellular $Ca^{2+}$ chelator, significantly blocked the cytotoxic effects of these extracts in U-373 cells, but enhanced these effects in SK-N-MC cells. These results suggest that the plant extracts may be a valuable choice for the studies on the treatment of human brain tumors.