• 통합자연과학논문집
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• 제6권3호
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• pp.125-137
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• 2013

Promising evidence suggests that amyloid beta peptide ($A{\beta}$), a key mediator in age-dependent neuronal and cerebrovascular degeneration, activates death signalling processes leading to neuronal as well as non-neuronal cell death in the central nervous system. A major cellular event in $A{\beta}$-induced apoptosis of non-neuronal cells, including cerebral endothelial cells, astrocytes and oligodendrocytes, is mitochondrial dysfunction. The apoptosis signalling cascade upstream of mitochondria entails $A{\beta}$ activation of neutral sphingomyelinase, resulting in the release of ceramide from membrane sphingomyelin. Ceramide then activates protein phosphatase 2A (PP2A), a member in the ceramide-activated protein phosphatase (CAPP) family. PP2A dephosphorylation of Akt and FKHRL1 plays a pivotal role in $A{\beta}$-induced Bad translocation to mitochondria and transactivation of Bim. Bad and Bim are pro-apoptotic proteins that cause mitochondrial dysfunction characterized by excessive ROS formation, mitochondrial DNA (mtDNA) damage, and release of mitochondrial apoptotic proteins including cytochrome c, apoptosis inducing factor (AIF), endonuclease G and Smac. The cellular events activated by $A{\beta}$ to induce death of non-neuronal cells are complex. Understanding these apoptosis signalling processes will aid in the development of more effective strategies to slow down age-dependent cerebrovascular degeneration caused by progressive cerebrovascular $A{\beta}$ deposition.

• 제어로봇시스템학회논문지
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• 제13권9호
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• pp.838-842
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• 2007

A brain-computer interface(BCI) system is a communication channel which transforms a subject's thought process into command signals to control various devices. These systems use electroencephalographic signals or the neuronal activity of many single neurons. The presented study deals with an efficient analysis method of neuronal signals from a BCI System using an independent component analysis(ICA) algorithm. The BCI system was implemented to generate event signals coding movement information of the subject. To apply the ICA algorithm, we obtained the perievent histograms of neuronal signals recorded from prefrontal cortex(PFC) region during target-to-goal(TG) task trials in the BCI system. The neuronal signals were then smoothed over 5ms intervals by low-pass filtering. The matrix of smoothed signals was then rearranged such that each signal was represented as a column and each bin as a row. Each column was also normalized to have a unit variance. As a result, we verified that different patterns of the neuronal signals are dependent on the target position and predefined event signals.

• 대한한의학회지
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• 제23권4호
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• pp.125-139
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• 2002

Objectives: The purpose of this investigation is to evaluate the effects of Woohwangcheongsim-won and to study the mechanism for neuronal death protection in OGD (oxygen-glucose deprivation) model with embryonic day 20 (E20) cortical cells of a rat (Sprague Dawley). Methods: E20 cortical cells were dissociated in neurobasal media and grown for 14 days in vitro (DIV). On 14 DIV, Woohwangcheongsim-won was added to the culture media for 72 hrs. On 17 DIV, cells were given an oxygen-glucose deprivation shock (2hrs and 4hrs) and further incubated in normoxia for another three days. On 20 DIV, Woohwangcheongsim-won's effects for neuronal death protection were evaluated by LDH assay and the mechanisms were studied by Bcl-2, Bak, Bax, caspase family. Results & Conclusions: 1. This study indicates that Woohwangcheongsim-won's effects for neuronal death protection in OGD model is confirmed by LDH assay in culture method of embryonic day 20(E20) cortical neuroblasts. 2. Woohwangcheongsim-won's mechanisms for neuronal death protection in OGD model are to restrain inflow of cytochrome c into cellularity caused by Bcl-2 increase (2hrs and 4hrs), to reduce the caspase cascade initiator caspase-8 (4hrs).

• Applied Microscopy
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• 제42권4호
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• pp.200-206
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• 2012

Induction of neurogenesis can occur in the hippocampus in response to various pathological conditions, such as Alzheimer's disease. The aim of this study was to investigate the changes that occur in endogenous neural stem cells in response to amyloid beta $(A{\beta})_{25-35}$-induced neuronal cell damage in organotypic hippocampal slice cultures. Cresyl violet staining and Fluoro-Jade B staining were used to detect neuronal cell damage and changes of mossy fiber terminals were observed by Timm's staining. The immunofl uorescence staining was used to detect the newly generated cells in the subgranular zone (SGZ) of the dentate gyrus with specific marker, 5-bromo-2'-deoxyuridine (BrdU), Ki-67, Nestin, and doublecortin (DCX). In compared to control slices, neuronal cell damage was observed and the mossy fibers were expanded to CA3 area by treatment with $A{\beta}_{25-35}$. Ki-67/Nestin- and BrdU/DCX-positive cells were detected in the SGZ. In conclusion, these results demonstrate that $A{\beta}$-induced neuronal damage results in an increase in endogenous neural stem cells in rat hippocampal slice cultures not only for gliosis but also for neurogenesis.

• Archives of Pharmacal Research
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• 제22권1호
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• pp.35-43
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• 1999

Overstimulation of both kainate (KA) and N-methyl-D-aspartate (NMDA) receptors has been reported to induce excitatoxicity which can be characterized by neuronal damage and formation of reactive oxygen free radicals. Neuroprotective effect of melatonin against KA-induced excitotoxicity have been documented in vitro and in vivo. It is, however, not clear whether melationin is also neuroportective against excitotoxicity mediated by NMDA receptors. In the present work, we tested the in vivo protective effects of striatally infused melatonin against the oxidative stress and neuronal damage induced by the injection of KA and NMDA receptors into the rat striatum. Melatonin implants consisting of 22-gauge stainless-steel cannule with melatonin fused inside the tip were placed bilaterally in the rat brain one week prior to intrastriatal injection of glutamate receptor subtype agonists. Melatonin showed protective effects against the elevation of lipid peroxidation induced by either KA or NMDA and recovered Cu, Zn-superoxide dismutase activities reduced by both KA and NMDA into the control level. Melatonin also clearly blocked both KA- and NMDA-receptor mediated neuronal damage assessed by the determination of choline acetyltransferase activity in striatal monogenages and by microscopic observation of rat brain section stained with cresyl violet. The protective effects of melatonin are comparable to those of DNQX and MK801 which are the KA- and NMDA-receptor antagonist, respectively. It is suggested that melatonin could protect against striatal oxidative damages mediated by glutamate receptors, both non-NMDA and NMDA receptors.

• 동의생리병리학회지
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• 제22권2호
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• pp.403-409
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• 2008

In Oriental medicine daeseungki-tang is one of the prescription that is used clinically for constipation of paralytics. The objective of the study was to observe the effect of daeseungki-tang on apoptotic neuronal cell death. In the present study, middle cerebral artery occlusion(MCAO) rats were treated with daeseungi-tang for 5 days and the edema percentage of cerebral hemisphere of MCAO rats were investigated primary. Secondary, appearances of Bax, Bcl-2,-factors that is related to apoptotic neuronal cell death - and HSP72 in the brain of MCAO rats were investigated via immunohistochemistry. Daeseungki-tang significantly decreased edema percentage of the cerebral hemisphere of MCAO rats. Daeseungki-tang significantly decreased Bax positive cells, but did not change the apperances of Bcl-2 positive cells in the penumbra of the cerebral cortex and the caudoputamen of MCAO rats. Daeseungki-tang significantly decreased HSP72 positive cells in the penumbra of the cerebral cortex, but not in the caudoputamen of MCAO rats. Based on the present results, it can be suggested that treatment with daeseungki-tang may decrease edema of the cerebral hemisphere and restrain apoptotic neuronal cell death in the penumbra of the cerebral cortex.

• Molecules and Cells
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• 제39권9호
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• pp.680-686
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• 2016

Uncoupling proteins (UCPs) are mitochondrial inner membrane proteins that function to dissipate proton motive force and mitochondrial membrane potential. One UCP has been identified in Caenorhabditis elegans (C. elegans), namely UCP-4. In this study, we examined its expression and localization using a GFP marker in C. elegans. ucp-4 was expressed throughout the body from early embryo to aged adult and UCP-4 was localized in the mitochondria. It is known that increased mitochondrial membrane protential leads to a reactive oxygen species (ROS) increase, which is associated with age-related diseases, including neurodegenerative diseases in humans. A ucp-4 mutant showed increased mitochondrial membrane protential in association with increased neuronal defects during aging, and the neurons of ucp-4 overexpressing animals showed decreased neuronal defects during aging. These results suggest that UCP-4 may be involved in neuroprotection during aging via relieving mitochondrial membrane protential. We also investigated the relationship between UCP-4 and innate immunity because increased ROS can affect innate immunity. ucp-4 mutant displayed increased resistance to the pathogen Staphylococcus aureus compared to wild type. The enhanced immunity in the ucp-4 mutant could be related to increased mitochondrial membrane protential, presumably followed by increased ROS. In summary, UCP-4 might have an important role in neuronal aging and innate immune responses through mediating mitochondrial membrane protential.

• Laboraroty Animal Research
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• 제33권3호
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• pp.244-250
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• 2017

${\alpha}$-Synuclein is abundantly expressed in neuronal tissue, plays an essential role in the pathogenesis of neurodegenerative disorders, and exerts a neuroprotective effect against oxidative stress. Cerebral ischemia causes severe neurological disorders and neuronal dysfunction. In this study, we examined ${\alpha}$-synuclein expression in middle cerebral artery occlusion (MCAO)-induced cerebral ischemic injury and neuronal cells damaged by glutamate treatment. MCAO surgical operation was performed on male Sprague-Dawley rats, and brain samples were isolated 24 hours after MCAO. We confirmed neurological behavior deficit, infarction area, and histopathological changes following MCAO injury. A proteomic approach and Western blot analysis demonstrated a decrease in ${\alpha}$-synuclein in the cerebral cortices after MCAO injury. Moreover, glutamate treatment induced neuronal cell death and decreased ${\alpha}$-synuclein expression in a hippocampal-derived cell line in a dose-dependent manner. It is known that ${\alpha}$-synuclein regulates neuronal survival, and low levels of ${\alpha}$-synuclein expression result in cytotoxicity. Thus, these results suggest that cerebral ischemic injury leads to a reduction in ${\alpha}$-synuclein and consequently causes serious brain damage.

• BMB Reports
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• 제54권12호
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• pp.626-631
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• 2021

Janus kinase 2 (JAK2), a non-receptor tyrosine kinase, is a critical component of cytokine and growth factor signaling pathways regulating hematopoietic cell proliferation. JAK2 mutations are associated with multiple myeloproliferative neoplasms. Although physiological and pathological functions of JAK2 in hematopoietic tissues are well-known, such functions of JAK2 in the nervous system are not well studied yet. The present study demonstrated that JAK2 could negatively regulate neuronal differentiation of mouse embryonic stem cells (ESCs). Depletion of JAK2 stimulated neuronal differentiation of mouse ESCs and activated glycogen synthase kinase 3β, Fyn, and cyclin-dependent kinase 5. Knockdown of JAK2 resulted in accumulation of GTP-bound Rac1, a Rho GTPase implicated in the regulation of cytoskeletal dynamics. These findings suggest that JAK2 might negatively regulate neuronal differentiation by suppressing the GSK-3β/Fyn/CDK5 signaling pathway responsible for morphological maturation.

• 약학회지
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• 제46권6호
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• pp.398-404
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• 2002

A phytochemical study on the root of Cibotium barometz J. Smith led to the isolation of onitin (I), daucosterol (II) and a new compound (III). Compound III was characterized as 2-Ο-(9Z,12Z-octadecadienoyl)-3-Ο-[$\alpha$-D-galactopyranosyl-(1"-6")-Ο-$\beta$-D-galactopyranosyl] glycerol, named shinbarometin by $^1$H-, $^{13}$ C-NMR and LC/MS data. Compound III exerted an induced neuronal regeneration on nogo-A induced neuroblastoma cells.