• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2001.11a
• /
• pp.91-91
• /
• 2001

Nramp2, also known as DMT1 and DCT1, is a 12-transmembrane domain protein responsible for dietary iron uptake as well as metal ions such as lead, manganese, zinc, copper, nickel, cadmium, and cobalt. High expression of DMT1 increase lead uptake, and DMT1-dependent lead transport was H -dependent and inhibited by iron ions. The molecular mechanism of lead transport in CNS is as yet unknown. although interactions between iron and lead at the level of absorption have been known for some time. The process of lead uptake into astrocytes was not known yet. Nramp2 may mediate transport of heavy metal into astrocytes. We investigated whether Nramp2 mediate transport of lead into astrocytes. And we do whether Nramp2 was expressed highly by deprivation of iron in Astrocytes, and lead uptake into astrocytes was influenced by expression of Nramp2. Immortalized human fetal astrocyte(SV-FHA) cells were cultured in medium containing Dulbecco's modified Eagle's medium and treated with Deferoxamine. Northern blot analysis was done for determining mRNA level of DMT1 and lead uptake assay was done in incubation condition of pH 5.5 and 7.4.

• Archives of Pharmacal Research
• /
• v.20 no.2
• /
• pp.103-109
• /
• 1997

The effects of ginseng total saponins (GTS) on hypoxic damage of primary cultures of astrocytes were studied. Hypoxia was created by placing cultures in an air tight chamber that was flushed with 95% $N_2/5%CO_2$ for 15 min before being sealed. Cultures showed evidence of significant cell injury after 24 h of hypoxia (increased lactate dehydrogenase (LDH) content in the culture medium, cell swelling and decreased glutamate uptake and protein content). Addition of GTS (0.1, 0.3 mg/ml) to the cultures during the exposure to hypoxic conditions produced dose-dependent inhibition of the LDH efflux. GTS (0.1, 0.3 mg/ml) also produced significant inhibition of the increased cell volume of astrocytes measured by $[^3H]$ O-methyl-D-glucose uptake under the hypoxic conditions. Decreased glutamate uptake and protein content was inhibited by GTS. These data suggest that GTS prevents astrocytic cell injury induced by severe hypoxia in vitro.

• Journal of Ginseng Research
• /
• v.37 no.4
• /
• pp.401-412
• /
• 2013

Korean Red Ginseng (KRG) is an oriental herbal preparation obtained from Panax ginseng Meyer (Araliaceae). To expand our understanding of the action of KRG on central nervous system (CNS) function, we examined the effects of KRG on tissue plasminogen activator (tPA)/plasminogen activator inhibitor-1 (PAI-1) expression in rat primary astrocytes. KRG extract was treated in cultured rat primary astrocytes and neuron in a concentration range of 0.1 to 1.0 mg/mL and the expression of functional tPA/PAI-1 was examined by casein zymography, Western blot and reverse transcription-polymerase chain reaction. KRG extracts increased PAI-1 expression in rat primary astrocytes in a concentration dependent manner (0.1 to 1.0 mg/mL) without affecting the expression of tPA itself. Treatment of 1.0 mg/mL KRG increased PAI-1 protein expression in rat primary astrocytes to $319.3{\pm}65.9%$ as compared with control. The increased PAI-1 expression mediated the overall decrease in tPA activity in rat primary astrocytes. Due to the lack of PAI-1 expression in neuron, KRG did not affect tPA activity in neuron. KRG treatment induced a concentration dependent activation of PI3K, p38, ERK1/2, and JNK in rat primary astrocytes and treatment of PI3K or MAPK inhibitors such as LY294002, U0126, SB203580, and SP600125 (10 ${\mu}M$ each), significantly inhibited 1.0 mg/mL KRG-induced expression of PAI-1 and down-regulation of tPA activity in rat primary astrocytes. Furthermore, compound K but not other ginsenosides such as Rb1 and Rg1 induced PAI-1 expression. KRG-induced up-regulation of PAI-1 in astrocytes may play important role in the regulation of overall tPA activity in brain, which might underlie some of the beneficial effects of KRG on CNS such as neuroprotection in ischemia and brain damaging condition as well as prevention or recovery from addiction.

• Journal of Ginseng Research
• /
• v.24 no.3
• /
• pp.138-142
• /
• 2000

Effects of ginsenosides (Rb$_1$, Rb$_2$, Rc, Re, Rg$_1$, Rf) on L-glutamate (glutamate)-induced swelling of cultured astrocytes from rat brain cerebral cortex were studied. Following the exposure to 0.5mM glutamate for 1 hr, the intracellular water space (as measured by [$^3$H]O-methyl-D-glucose uptake) of astrocytes increased by about two-fold. Simultaneous addition of ginsenosides Rb$_2$ and Rc with glutamate reduced the astrocytic swelling in a dose-dependent manner. These ginsenosides at 0.5 mg/ml did not affect the viability of astrocytes for up to 24 hr which was determined by a colorimetric assay (MTT assay) for cellular growth and survival. These ginsenosides at 0.3 mg/ml inhibited the increase of intracellular Ca$\^$2+/ concentration ([Ca$\^$2+/]$\_$i/) induced by glutamate. These data suggest ginsenosides Rb$_2$ and Rc prevent the cell swelling of astrocytes induced by glutamate, maybe via inhibition of Ca$\^$2+/ influx.

• Biomolecules & Therapeutics
• /
• v.31 no.1
• /
• pp.116-126
• /
• 2023

Mainly due to the slanted focus on the mechanism and regulation of neuronal aging, research on astrocyte aging and its modulation during brain aging is scarce. In this study, we established aged astrocyte culture model by long-term culturing. Cellular senescence was confirmed through SA-β-gal staining as well as through the examination of morphological, molecular, and functional markers. RNA sequencing and functional analysis of astrocytes were performed to further investigate the detailed characteristics of the aged astrocyte model. Along with aged phenotypes, decreased astrocytic proliferation, migration, mitochondrial energetic function and support for neuronal survival and differentiation has been observed in aged astrocytes. In addition, increased expression of cytokines and chemokine-related factors including plasminogen activator inhibitor -1 (PAI-1) was observed in aged astrocytes. Using the RNA sequencing results, we searched potential drugs that can normalize the dysregulated gene expression pattern observed in long-term cultured aged astrocytes. Among several candidates, minoxidil, a pyrimidine-derived anti-hypertensive and anti-pattern hair loss drug, normalized the increased number of SA-β-gal positive cells and nuclear size in aged astrocytes. In addition, minoxidil restored up-regulated activity of PAI-1 and increased mitochondrial superoxide production in aged astrocytes. We concluded that long term culture of astrocytes can be used as a reliable model for the study of astrocyte senescence and minoxidil can be a plausible candidate for the regulation of brain aging.

• The Korean Journal of Physiology and Pharmacology
• /
• v.10 no.5
• /
• pp.263-271
• /
• 2006

Since astrocytes were shown to play a central role in maintaining neuronal viability both under normal conditions and during stress such as ischemia, studies of the astrocytic response to stress are essential to understand many types of brain pathology. The micro array system permitted screening of large numbers of genes in biological or pathological processes. Therefore, the gene expression patterns in the in vitro model of astrocytes following exposure to oxygen-glucose deprivation (OGD) were evaluated by using the micro array analysis. Primary astrocytic cultures were prepared from postnatal Swiss Webster mice. The cells were exposed to OGD for 4 hrs at $37^{\circ}C$ prior to cell harvesting. From the cultured cells, we isolated mRNA, synthesized cDNA, converted to biotinylated cRNA and then reacted with GeneChips. The data were normalized and analyzed using dChip and GenMAPP tools. After 4 hrs exposure to OGD, 4 genes were increased more than 2 folds and 51 genes were decreased more than 2 folds compared with the control condition. The data suggest that the OGD has general suppressive effect on the gene expression with the exception of some genes which are related with ischemic cell death directly or indirectly. These genes are mainly involved in apoptotic and protein translation pathways and gap junction component. These results suggest that microarray analysis of gene expression may be useful for screening novel molecular mediators of astrocyte response to ischemic injury and making profound understanding of the cellular mechanisms as a whole. Such a screening technique should provide insights into the molecular basis of brain disorders and help to identify potential targets for therapy.

• Journal of Life Science
• /
• v.21 no.2
• /
• pp.176-182
• /
• 2011

Deep seawater (DSW) generally refers to seawater at depths equal to or greater than 200 meters. DSW is rich in inorganic materials which have attracted attention for its various applications. In this study we investigated the effects of the DSW upwelled from the East Sea, offshore Yang Yang (KangWon-do, Korea), on the expression of ${\mu}$-opioid receptor (MOR) of cultured rat hippocampal neurons. Neurons were grown in a minimal essential medium containing 10% (v/v) fetal bovine serum and either 25% (v/v) distilled water, or hardness (H) 800, or H 1000 DSW. Cultures grown in the presence of DSW with H 800 and H 1000 exhibited robust MOR immunoreactive signals in both neurons and astrocytes. Interestingly, the increase in MOR immunoreactive signals was more dramatic in astrocytes than in neurons. Statistical analysis revealed that the relative intensities for MOR clusters increased approximately 4-fold in astrocytes cultured in H 800 and H 1000 media. These increases were statistically very significant (p<0.001). In contrast, the increase in intensities for MOR immunoreactive signals was relatively less dramatic in neurons, where only the increase in the H 1000 culture was statistically very significant (p<0.001). These results indicated that DSW promotes expression of MOR in both neurons and astrocytes, and more significantly in the latter.

• Korean Journal of Veterinary Research
• /
• v.31 no.2
• /
• pp.155-161
• /
• 1991

The mechanisms of demyelination in Theiler's murine encephalomyelitis virus (TMEV)-induced chronic central nervous system(CNS) disease are still unclear and are probably multifactoral. This study was intended to culture spinal cord cells isolated from TMEV-induced demyelinating mice. By Percoll density centrifugation of enzymatically dissociated tissue, the cells were collected and then cultured on poly-L-lysine-coated plastic coverslips for 2 weeks. Oligodendrocytes, astrocytes and macrophages were identified using cell-type specific markers. Viral antigens were not present in oligodendrocytes and in astrocytes by double immunofluorescence. Affected mouse oligodendrocytes had less capacities of sheet formation and galactocerebroside immunoreactivity than those of control cell 3. These findings support the hypothesis that immune mediated mechanisms play an important role in the process of demyelination in this animal model.

• Journal of Oriental Neuropsychiatry
• /
• v.20 no.2
• /
• pp.31-46
• /
• 2009

Objectives : This experiment was designed to investigate the effect of Gojineumja(Guzhenyinzi, GJEJ) on damaged neural tissue in cultured glial cells and in the mouse brain tissue. Methods : The effects of the GJEJ on activation of astrocytes and caspase 3-positive cell counts in cultured glial cells administered with ${\beta}$-amyloid peptide were investigated. The effects of the GJEJ on levels of glial fibrillary acidic protein(GFAP)-positive reactive astrocyets and caspase 3-positive cells in the hippocampal subfields in the rats administered with scopolamine were investigated. Results : 1. GJEJ reduced levels of activated astrocytes and caspase 3-positive cell counts in cultured glial cells administered with ${\beta}$-amyloid peptide. 2. GJEJ reduced levels of GFAP-positive reactive astrocyets and caspase 3-positive cells in the hippocampal subfields in the rats administered with scopolamine. Conclusions : The present data. suggest that GJEJ may have a protective function of neuronal and non-neuronal cells in damaged neural tissue caused by AD-like stimulations. Further studies on identification of effective molecular components of GJEJ and their interactions with damaged neural cells would be important for understanding molecular mechanism and may be further applicable for the development of therapeutic strategies.

• The Korean Journal of Physiology and Pharmacology
• /
• v.3 no.2
• /
• pp.127-135
• /
• 1999

As part of a study on the effects of dexamethasone and dehydroepiandrosterone (DHEA) on the biological roles of astrocytes in brain injury, this study evaluated the effects of dexamethasone and DHEA on the responses of primary cultured rat cortical astrocytes to lipopolysaccharide (LPS) and antimycin A. Dexamethasone decreased spontaneous release of LDH from astrocytes, and the dexamethasone effect was inhibited by DHEA. However, the inhibitory effect of DHEA on the dexamethasone-induced decrease of LDH release was not shown in astrocytes treated with LPS, and antimycin A-induced LDH release was not affected by dexamethasone or DHEA. Unlike dexamethasone, DHEA increased MTT value of astrocytes and also attenuated the antimycin A-induced decrease of MTT value. Glutamine synthetase activity of astrocytes was not affected by DHEA or LPS but increased by dexamethasone, and the dexamethasone- dependent increase was attenuated by DHEA. However, antimycin A markedly decreased glutamine synthetase activity, and the antimycin A effect was not affected by dexamethasone or DHEA. Basal release of $[^3H]arachidonic$ acid from astrocytes was moderately increased by LPS and markedly by antimycin A. Dexamethasone inhibited the basal and LPS-dependent releases of $[^3H]arachidonic$ acid, but neither dexamethasone nor DHEA affected antimycin A-induced $[^3H]arachidonic$ acid release. Basal IL-6 release from astrocytes was not affected by dexamethasone or DHEA but markedly increased by LPS and antimycin A. LPS-induced IL-6 release was attenuated by dexamethasone but was little affected by DHEA, and antimycin A-induced IL-6 release was attenuated by DHEA as well as dexamethasone. At the concentration of dexamethasone and DHEA which does not affect basal NO release from astrocytes, they moderately inhibited LPS-induced NO release but little affected antimycin A-induced decrease of NO release. Taken together, these results suggest that dexamethasone and DHEA, in somewhat different manners, modulate the astrocyte reactivity in brain injuries inhibitorily.