• BMB Reports
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• 제54권6호
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• pp.317-322
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• 2021

CCCTC-binding factor (CTCF), a zinc finger protein, is a transcription factor and regulator of chromatin structure. Forebrain excitatory neuron-specific CTCF deficiency contributes to inflammation via enhanced transcription of inflammation-related genes in the cortex and hippocampus. However, little is known about the long-term effect of CTCF deficiency on postnatal neurons, astrocytes, or microglia in the hippocampus of adult mice. To address this, we knocked out the Ctcf gene in forebrain glutamatergic neurons (Ctcf cKO) by crossing Ctcf-floxed mice with Camk2a-Cre mice and examined the hippocampi of 7.5-10-month-old male mice using immunofluorescence microscopy. We found obvious neuronal cell death and reactive gliosis in the hippocampal cornu ammonis (CA)1 in 7.5-10-month-old cKO mice. Prominent rod-shaped microglia that participate in immune surveillance were observed in the stratum pyramidale and radiatum layer, indicating a potential increase in inflammatory mediators released by hippocampal neurons. Although neuronal loss was not observed in CA3, and dentate gyrus (DG) CTCF depletion induced a significant increase in the number of microglia in the stratum oriens of CA3 and reactive microgliosis and astrogliosis in the molecular layer and hilus of the DG in 7.5-10-month-old cKO mice. These results suggest that long-term Ctcf deletion from forebrain excitatory neurons may contribute to reactive gliosis induced by neuronal damage and consequent neuronal loss in the hippocampal CA1, DG, and CA3 in sequence over 7 months of age.

• BMB Reports
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• 제51권8호
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• pp.394-399
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• 2018

Human immunodeficiency virus-1 (HIV-1) transactivator of transcription (Tat) is an important viral factor in neuro-inflammation. Hindsiipropane B, present in Celastrus hindsii, possesses various biological mechanisms including anti-inflammatory activity. In this report, we explored the regulatory activity of hindsiipropane B on HIV-1 Tat-mediated chemokine production and its mode of action in astrocytes. Hindsiipropane B significantly alleviated HIV-1 Tat-mediated production of inflammatory chemokines, CCL2, CXCL8, and CXCL10. Hindsiipropane B inhibited expression of HDAC6, which is important regulator in HIV-1 Tat-mediated chemokine production. Hindsiipropane B diminished HIV-1 Tat-mediated reactive oxygen species (ROS) generation and NADPH oxidase activation/expression. Furthermore, hindsiipropane B inhibited HIV-1 Tat-mediated signaling cascades including MAPK, $NF-{\kappa}B$, and AP-1. These data suggest that hindsiipropane B exerts its inhibitory effects on HIV-1 Tat-mediated chemokine production via down-regulating the HDAC6-NADPH oxidaseMAPK-$NF-{\kappa}B$/AP-1 signaling axis, and could serve as a therapeutic lead compound against HIV-1 Tat-associated neuro-inflammation.

• Biomolecules & Therapeutics
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• 제20권1호
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• pp.68-74
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• 2012

Anthocyanins have received growing attention as dietary antioxidants for the prevention of oxidative damage. Astrocytes, which are specialized glial cells, exert numerous essential, complex functions in both healthy and diseased central nervous system (CNS) through a process known as reactive astrogilosis. Therefore, the maintenance of glial cell viability may be important because of its role as a key modulator of neuropathological events. The aim of this study was to investigate the effect of anthocyanin on the survival of glial cells exposed to oxidative stress. Our results demonstrated that anthocyanin extracts from black soybean increased survival of U87 glioma cells in a dose dependent manner upon oxygen-glucose deprivation (OGD), accompanied by decrease levels of reactive oxygen species (ROS). While treatment cells with anthocyanin extracts or OGD stress individually activated autophagy induction, the effect was signifi cantly augmented by pretreatment cells with anthocyanin extracts prior to OGD. The contribution of autophagy induction to the protective effects of anthocyanin was verifi ed by the observation that silencing the Atg5 expression, an essential regulator of autophagy induction, reversed the cytoprotective effect of anthocyanin extracts against OGD stress. Treatment of U87 cells with rapamycin, an autophagy inducer, increased cell survival upon OGD stress comparable to anthocyanin, indicating that autophagy functions as a survival mechanism against oxidative stress-induced cytotoxicity in glial cells. Our results, therefore, provide a rationale for the use of anthocyanin as a preventive agent for brain dysfunction caused by oxidative damage, such as a stroke.

• BMB Reports
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• 제46권7호
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• pp.370-375
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• 2013

Ischemia is characterized by oxidative stress and changes in the antioxidant defense system. Our recent in vitro study showed that 2-cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride protects cortical astrocytes against oxidative stress. In the current study, we examined the effects of 2-cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride on ischemia-induced neuronal damage in a gerbil ischemia/reperfusion models. Extensive neuronal death in the hippocampal CA1 area was observed 4 days after ischemia/reperfusion. Intraperitoneal injection of 2-cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride (0.3 mg/kg body weight) significantly prevented neuronal death in the CA1 region of the hippocampus in response to transient forebrain ischemia. 2-Cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride administration reduced ischemia-induced increases in reactive oxygen species levels and malondialdehyde content. It also attenuated the associated reductions in glutathione level and superoxide dismutase, catalase, and glutathione peroxidase activities. Taken together, our results suggest that 2-cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride protects against ischemia-induced neuronal damage by reducing oxidative stress through its antioxidant actions.

• International Journal of Oral Biology
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• 제45권4호
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• pp.225-231
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• 2020

Glial cells, including astrocytes and microglia, interact closely with neurons and modulate pain transmission, particularly under pathological conditions. In this study, we examined the excitability of substantia gelatinosa (SG) neurons of the spinal dorsal horn using a patch clamp recording to investigate the roles of microglial activation in the nociceptive processes of rats. We used xanthine/xanthine oxidase (X/XO), a generator of superoxide anion (O2·-), to induce a pathological pain condition. X/XO treatment induced an inward current and membrane depolarization. The inward current was significantly inhibited by minocycline, a microglial inhibitor, and fluorocitrate, an astrocyte inhibitor. To examine whether toll-like receptor 4 (TLR4) in microglia was involved in the inward current, we used lipopolysaccharide (LPS), a highly specific TLR4 agonist. The LPS induced inward current, which was decreased by pretreatment with Tak-242, a TLR4-specific inhibitor, and phenyl N-t-butylnitrone, a reactive oxygen species scavenger. The X/XO-induced inward current was also inhibited by pretreatment with Tak-242. These results indicate that the X/XO-induced inward current of SG neurons occurs through activation of TLR4 in microglial cells, suggesting that neuroglial cells modulate the nociceptive process through central sensitization.

• Toxicological Research
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• 제11권2호
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• pp.315-327
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• 1995

Diverse neurotoxic insults result in proliferation and hypertrophy of astrocytes, a subtype of glia in central nervous system. The hallmark of this response, often terms "reactive gliosis", is the enhanced expression of the major intermediate filament protein of castrocytes, glial fibrillary acidic protein (GFAP). These changes in the astrocytes suggest that GFAP may be a useful biochemical indicator of neurotoxicity. To investigate this possibility, we administered intra-peritoneally prototype nerotoxicants, metharnphetamine (MAP, 5 mg/kg), cocaine (30 mg/kg), N-buthyl benzenesulfonamide (NBBS, 300 mg/kg) and trimethytin (TMT, 8 mg/kg) to Wistar Rats and then assessed the effects of these agents on content of GFAP, which were determined by Sandwish ELISA and evaluated with neurotoxic symptoms, and quantitative changes of imrnunoreactivity of GFAP by light microscopic image analysis in specific regions. We found that assay of GFAP revealed time- and region-dependant patterns of neurotoxicity. The GFAP immunoreactivity of rat brain was increased in substantia nigra and hippocampus by MAP, NBBS and TMT; in roedial septal nucleus and nucleus accurnbens, it was also increased by RrBBS. Sandwich ELISA showed that GFAP levels of cerebrum in all groups on days 3 and 7 and that of brainstem(including cerebellum) in MAP, NBBS groups on day 1 and 3 were increased. A review of the background, design and results of these experiments are presented in this paper. Our findings indicate that GFAP is a sensitive and specific biomarker of neurotoxicity.otoxicity.

• 생명과학회지
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• 제23권1호
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• pp.125-130
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• 2013

Calponin 3는 F-actin과 결합하는 단백질로 신경계의 가소성과 시냅스 활성을 조절하는데 중요한 역할을 하는 것으로 알려져 있다. 평활근과 심장근에 발현되는 calponin 1과 calponin 2와는 다르게 calponin 3는 뇌 조직에 많이 발현되어 있는 것으로 보고되고 있다. 본 연구는 마우스에서 3-nitropropionic acid를 투여하여 선조체에 비가역적 신경 손상을 주었을 때 calponin 3의 발현 양상을 알아보기 위하여 진행되었다. 본 연구 결과 3-nitropropionic acid를 마우스에 투여하였을 때 선조체에서 신경조직의 괴사가 일어남을 관찰하였으며 calponin 3는 약물 투여 후 1.5일부터 서서히 발현되는 것을 확인하였다. 특히, calponin 3는 신경조직의 괴사가 일어나는 부위의 주변부에서 발현되는 것을 확인하였으며 형광 이중면역 염색법으로 확인한 결과 GFAP를 발현하는 별아교세포에서 발현됨을 최초로 밝혔다. 따라서, calponin 3가 3-nitropropionic acid의 독성에 저항성을 나타내는 부위에서 별아교세포에서만 특이적으로 발현되는 것으로 보아 calponin 3는 별아교세포에 의한 신경아교증에 중요한 역할을 하는 것으로 추측된다.

• 대한약침학회지
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• 제12권1호
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• pp.67-76
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• 2009

Objective : Following central nervous system(CNS) injury, inhibitory influences at the site of axonal damage occur. Glial cells become reactive and form a glial scar, gliosis. Also myelin debris such as MAG inhibits axonal regeneration. Astrocyte-rich gliosis relates with up-regulation of GFAP and CD81, and eventually becomes physical and mechanical barrier to axonal regeneration. MAG is one of several endogenous axon regeneration inhibitors that limit recovery from CNS injury and disease. It was reported that molecules that block such inhibitors enhanced axon regeneration and functional recovery. Recently it was reported that treatment with anti-CD81 antibodies enhanced functional recovery in the rat with spinal cord injury. So in this current study, the author investigated the effect of the water extract of Uncariae Ramulus et Uncus on the regulation of CD81, GFAP and MAG that increase when gliosis occurs. Methods : MTT assay was performed to examine cell viability, and cell-based ELISA, western blot and PCR were used to detect the expression of CD81, GFAP and MAG. Then also immunohistochemistry was performed to confirm in vivo. Results : Water extract of Uncariae Ramulus et Uncus showed relatively high cell viability at the concentration of 0.05%, 0.1% and 0.5%. The expression of CD81, GFAP and MAG in astrocytes was decreased after the administration of Uncariae Ramulus et Uncus water extract. These results was confirmed in the brain sections following cortical stab injury by immunohistochemistry. Conclusion : The authors observed that Uncariae Ramulus et Uncus significantly down-regulates the expression of CD81, GFAP and MAG. These results suggest that Uncariae Ramulus et Uncus can be a candidate to regenerate CNS injury.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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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.

• 대한수의학회지
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• 제54권4호
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• pp.209-218
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• 2014

Experimental autoimmune encephalomyelitis (EAE), an animal model of human multiple sclerosis (MS), reflects pathophysiologic steps in MS such as the influence of T cells and antibodies reactive to the myelin sheath, and the cytotoxic effect of cytokines. Galectin-9 (Gal-9) is a member of animal lectins that plays an essential role in various biological functions. The expression of Gal-9 is significantly enhanced in MS lesions; however, its role in autoimmune disease has not been fully elucidated. To identify the role of Gal-9 in EAE, we measured changes in mRNA and protein expression of Gal-9 as EAE progressed. Expression increased with disease progression, with a sharp rise occurring at its peak. Gal-9 immunoreactivity was mainly expressed in astrocytes and microglia of the central nervous system (CNS) and macrophages of spleen. Flow cytometric analysis revealed that $Gal-9^+CD11b^+$ cells were dramatically increased in the spleen at the peak of disease. Increased expression of tumor necrosis factor (TNF)-R1 and p-Jun N-terminal kinase (JNK) was observed in the CNS of EAE mice, suggesting that TNF-R1 and p-JNK might be key regulators contributing to the expression of Gal-9 during EAE. These results suggest that identification of the relationship between Gal-9 and EAE progression is critical for better understanding Gal-9 biology in autoimmune disease.