• Journal of Life Science
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• v.23 no.9
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• pp.1096-1103
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• 2013

Chronic traumatic encephalopathy (CTE), which is common in athletes, is a progressive neurodegenerative disease and a long-term consequence of repetitive closed head injuries. CTE is regarded as a chronic brain syndrome due to the effects of repetitive traumatic brain injury (TBI). Because neurotrophic factors are neuroprotective in models of brain and spinal cord injuries, we examined the effects of cerebrolysin, a mixture of various neurotrophic factors, on brain pathology in a mouse model of repetitive mild TBI (rmTBI), which is a good model of CTE. Five groups were created and treated as follows: groups 1 and 2: rmTBI for 4 weeks following cerebrolysin injection for 4 weeks; groups 3 and 4: rmTBI for 8 weeks with or without cerebrolysin injection for 4 weeks; group 5: control. We found that p-tau expression was increased in the pyramidal layer of the cortex and hippocampus, particularly the CA3 region, but not in the CA1 region and the dentate gyrus (DG). Intra-tail vein administration of cerebrolysin ($10{\mu}l$ of 1 mg/ml) after/during rmTBI treatment reduced p-tau expression in both the cortex and hippocampus. Histological analysis revealed mild astrocyte activation (increased expression of glial fibrillary acidic protein (GFAP)) but not microglia activation (ionized calcium binding adaptor molecule 1 (iba-1) expression) and peripheral macrophage infiltration (CD45). Additionally, administration of cerebrolysin after rmTBI resulted in reduced astrocyte activation. These observations in rmTBI demonstrated that cerebrolysin treatment reduces phosphorylation of tau and astrocyte activation, attenuates brain pathology, and mitigates function deficits in TBI. Taken together, our observations suggest that cerebrolysin has potential therapeutic value in CTE.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.19-29
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• 1996

The neurological manifestations of AIDS include dementia, encountered even in the absence of opportunistic superinfection or malignancy. The AIDS Dementia Complex appears to be associated with several neuropathological abnormalities, including astrogliosis and neuronal injury or loss. How can HIV-1 result in neuronal damage if neurons themselves are only rarely, if ever, infected by the vitus\ulcorner In vitro experiments from several different laboratiories have lent support to the existence of HIV- and immune-related toxins. In one recently defined pathway to neuronal injury, HIV-infected macrophages/microglia as well as macrophages activated by HIV-1 envelope protein gp120 appear to secrete excitants/neurotoxins. These substances may include arachidonic acid, platelet-activating factor, free radicals (NO - and O$_2$), glutamate, quinolinate, cysteine, cytokines (TNF-${\alpha}$, IL1-B, IL-6), and as yet unidentified factors emanating from stimulated macrophages and possibly reactive astrocytes. A final common pathway for newonal suscepubility appears to be operative, similar to that observed in stroke, trauma, epilepsy, and several neurodegenerative diseases, including Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis. This mechanism involves excessive activation of N-methyl-D-aspartate (NMDA) receptor-operated channels, with resultant excessive influx of Ca$\^$2+/ leading to neuronal damage, and thus offers hope for future pharmacological intervention. This chapter reviews two clinically-tolerated NMDA antagonists, memantine and nitroglycerin; (ⅰ) Memantine is an open-channel blocker of the NMDA-associated ion channel and a close congener of the anti-viral and anti-parkinsonian drug amantadine. Memantine blocks the effects of escalating levels of excitotoxins to a greater degree than lower (piysiological) levels of these excitatory amino acids, thus sparing to some extent normal neuronal function. (ⅱ) Niuoglycerin acts at a redox modulatory site of the NMDA receptor/complex to downregulate its activity. The neuroprotective action of nitroglycerin at this site is mediated by n chemical species related to nitric oxide, but in a higher oxidation state, resulting in transfer of an NO group to a critical cysteine on the NMDA receptor. Because of the clinical safety of these drugs, they have the potential for trials in humans. As the structural basis for redox modulation is further elucidated, it may become possible to design even better redox reactive reagents of chinical value. To this end, redox modulatory sites of NMDA receptors have begun to be characterized at a molecular level using site-directed mutagenesis of recombinant subunits (NMDAR1, NMDAR2A-D). Two types of redox modulation can be distinguished. The first type gives rise to a persistent change in the functional activity of the receptor, and we have identified two cysteine residues on the NMDARI subunit (#744 and #798) that are responsible for this action. A second site, presumably also a cysteine(s) because <1 mM N-ethylmaleimide can block its effect in native neurons, underlies the other, more transient redox action. It appears to be at this, as yet unidentified, site on the NMDA receptor that the NO group acts, at least in recombinant receptors.

• Biomolecules & Therapeutics
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• v.15 no.1
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• pp.16-26
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• 2007

Tissue plasminogen activator (tPA) is a serine protease catalyzing the proteolytic conversion of plasminogen into plasmin, which is involved in thrombolysis. During last two decades, the role of tPA in brain physiology and pathology has been extensively investigated. tPA is expressed in brain regions such as cortex, hippocampus, amygdala and cerebellum, and major neural cell types such as neuron, astrocyte, microglia and endothelial cells express tPA in basal status. After strong neural stimulation such as seizure, tPA behaves as an immediate early gene increasing the expression level within an hour. Neural activity and/or postsynaptic stimulation increased the release of tPA from axonal terminal and presumably from dendritic compartment. Neuronal tPA regulates plastic changes in neuronal function and structure mediating key neurologic processes such as visual cortex plasticity, seizure spreading, cerebellar motor learning, long term potentiation and addictive or withdrawal behavior after morphine discontinuance. In addition to these physiological roles, tPA mediates excitotoxicity leading to the neurodegeneration in several pathological conditions including ischemic stroke. Increasing amount of evidence also suggest the role of tPA in neurodegenerative diseases such as Alzheimer's disease and multiple sclerosis even though beneficial effects was also reported in case of Alzheimer's disease based on the observation of tPA-induced degradation of $A{\beta}$ aggregates. Target proteins of tPA action include extracellular matrix protein laminin, proteoglycans and NMDA receptor. In addition, several receptors (or binding partners) for tPA has been reported such as low-density lipoprotein receptor-related protein (LRP) and annexin II, even though intracellular signaling mechanism underlying tPA action is not clear yet. Interestingly, the action of tPA comprises both proteolytic and non-proteolytic mechanism. In case of microglial activation, tPA showed non-proteolytic cytokine-like function. The search for exact target proteins and receptor molecules for tPA along with the identification of the mechanism regulating tPA expression and release in the nervous system will enable us to better understand several key neurological processes like teaming and memory as well as to obtain therapeutic tools against neurodegenerative diseases.

• Korean journal of applied entomology
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• v.45 no.1 s.142
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• pp.31-36
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• 2006

Inflammation in the brain has known to be associated with the development of a various neurologiacal diseases. The hallmark of neuro-inflammation is the activation of microglia, brain macrophage. Pro-inflammatory compounds including nitric oxide(NO) are the main cause of neuro-degenerative disease such as Alzheimer's disease. In the study, we examined whether Harmonia axyridis extracts inhibit the NO production by a direct method using Griess reagent, western blotting and by RT-PCR(Reverse Transcription-Polymerase Chain Reactionin) the gene expression of inducible nitric oxide synthase(iNOS). Distilled water$(H_2O)$ and methanol(MeOH) extracts of H. axyridis inhibited the protein expression of TNF-a(Tumor Necrosis Factor) and IL-6(Interleukin) in LPS (Lipopolysaccharide) stimulated BV-2 cells at the concentration of 100 ng/ml. Incubation of BV-2 cells with the extracts of $H_2O$ of MeOH inhibited the LPS induced NO and iNOS protein. And this inhibition of iNOS protein is concordant with the inhibition of iNOS mRNA expression. These data suggested that H. axyridis extracts may play a crucial role in inhibiting the NO production.

• IMMUNE NETWORK
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• v.6 no.1
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• pp.27-32
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• 2006

Background: Chronic inflammation in the brain has known to be associated with the development of a various neurological diseases including dementia. In general, the characteristic of neuro-inflammation is the activated microglia over the brain where the pathogenesis occurs. Pro-inflammatory repertoires, interleukin-1${\beta}$ (IL-1${\beta}$) and nitric oxide (NO), are the main causes of neuro-degenerative disease, particularly in Alzheimer's disease (AD) which is caused by neuronal destruction. Those pro-inflammatory repertoires may lead the brain to chronic inflammatory status, and thus we hypothesized that chronic inflammation would be inhibited when pro-inflammatory repertoires are to be well controlled by inactivating the signal transduction associated with inflammation. Methods: In the present study, we examined whether biphenyl dimethyl dicarboxylate (DDB), an active compound from Schizandra chinensis Baillon, inhibits the NO production by a direct method using Griess reagent and by RT-PCR in the gene expression of inducible nitric oxide synthase (iNOS) and IL-1${\beta}$. Western blots were also used for the analysis of NF-${\kappa}B$ and I${\kappa}B$. Results: In the study, we found that DDB effectively inhibited IL-1${\beta}$ as well as NO production in BV-2 microglial cell, and the translocation of NF-${\kappa}B$ was comparably inhibited in the presence of DDB comparing those to the positive control, lipopolysaccharide. Conclusion: The data suggested that the DDB from Schizandra chinensis Baillon may play an effective role in inhibiting the pro-inflammatory repertoires which may cause neurodegeneration and the results imply that the compound suppresses a cue signal of the microglial activation which can induce the brain pathogenesis such as Alzheimer's disease.

• Biomolecules & Therapeutics
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• v.29 no.3
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• pp.321-330
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• 2021

Oxidative stress plays a crucial role in the development of neuronal disorders including brain ischemic injury. Thioredoxin 1 (Trx1), a 12 kDa oxidoreductase, has anti-oxidant and anti-apoptotic functions in various cells. It has been highly implicated in brain ischemic injury. However, the protective mechanism of Trx1 against hippocampal neuronal cell death is not identified yet. Using a cell permeable Tat-Trx1 protein, protective mechanism of Trx1 against hydrogen peroxide-induced cell death was examined using HT-22 cells and an ischemic animal model. Transduced Tat-Trx1 markedly inhibited intracellular ROS levels, DNA fragmentation, and cell death in H2O2-treatment HT-22 cells. Tat-Trx1 also significantly inhibited phosphorylation of ASK1 and MAPKs in signaling pathways of HT-22 cells. In addition, Tat-Trx1 regulated expression levels of Akt, NF-κB, and apoptosis related proteins. In an ischemia animal model, Tat-Trx1 markedly protected hippocampal neuronal cell death and reduced astrocytes and microglia activation. These findings indicate that transduced Tat-Trx1 might be a potential therapeutic agent for treating ischemic injury.

• The Korea Journal of Herbology
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• v.36 no.6
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• pp.1-8
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• 2021

Objectives : Atractylodis rhizoma Alba has been traditionally used as a medicinal resource that is used for enhancing Qi (氣) in traditional medicine in Korea, China, and Japan. This study investigated the protective effects of Atractylodis rhizoma Alba extract (ARE) against trimethyltin (TMT), a neurotoxin that causes selective hippocampal injury, using both in vitro and in vivo models. Methods : We investigated the effects of ARE on TMT- (5mM) induced cytotoxicity in primary cultures of mouse hippocampal cells (7 days in vitro ) and on hippocampal injury in C57BL/6 mice injected with TMT (2.6 mg/kg). Results : We observed that ARE treatment (0 - 50 ㎍/mL) significantly reduced TMT-induced cytotoxicity in cultured hippocampal neurons in a dose-dependent manner, based on results of lactate dehydrogenase and 3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assays. Additionally, this study showed that orally administered ARE (5 mg/kg; between -6 and 0 days before TMT injection) significantly attenuated seizures in adult mice. Furthermore, quantitative analysis of allograft inflammatory factor-1 (Iba-1)- and glial fibrillary acidic protein (GFAP)- positive cells showed significantly reduced levels of Iba-1- and GFAP-positive cell bodies in the dentate gyrus of mice treated with ARE prior to TMT injection. These findings indicate the significant protective effects of ARE against the TMT-induced massive activation of microglia and astrocytes in the hippocampus. Conclusions : We conclude that ARE minimizes the detrimental effects of TMT-induced hippocampal neurotoxicity, both in vitro and in vivo . Our findings may serve as useful guidelines to support ARE administration as a promising pharmacotherapeutic approach to hippocampal degeneration.

• Applied Microscopy
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• v.35 no.3
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• pp.165-176
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• 2005

Studies on molecular plasticity of Bermann glia (BG) after harmaline-induced Purkinje cell (PC) degeneration in the rat cerebellum. The intimate structural relationship between BG and PC, evidenced by the sheathing of the PC dendrites by veil-like process from the BG has been suggestive of the close functional relationship between these two cell types. However, little is known about metabolic couplings between these cells. This study designed to investigate molecular plasticity of BG in the rat cerebellum in which PCs were chemically ablated by harmaline treatment. Immunohistochemical examination reveals that harmaline induced PC degeneration causes a marked glial reaction in the cerebellum with activated BG and microglia aligned in parasagittal stripes within the vermis. In these strips, activated BG were associated with upregulaion of metallotheionein, while GLAST and was down regulated, as compared with nearby intact area where both BG are in contact with PCs. The data from this study demonstrate that BG can change their phenotypic expression when BG loose their contact with PCs. It is conceivable that activated BG may upregulate structural proteins, metallothionein expression to use for their proliferation and hypertrophy; metallothionein expression to cope with oxidative stress induced by PC degeneration and microglial activation. On the contrary, BG may down regulated expression of GLAST because sustained loss of contact with PCs would eliminate the necessity for the cellular machinery involved glutamate metabolism. In conclusion, BG might respond man to death of PCs by undergoing a change in metabolic state. It seems possible that signaling molecules released from PCs regulates the phenotype expression of BG. Also ultrastructures in the organelles of normal PC and BG are distinguished by mitochondrial appearance, and distributed vesicles at the synaptic area in the cytoplasm.