• BMB Reports
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• v.53 no.2
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• pp.118-123
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• 2020

Cardiac regeneration with adult stem-cell (ASC) therapy is a promising field to address advanced cardiovascular diseases. In addition, extracellular vesicles (EVs) from ASCs have been implicated in acting as paracrine factors to improve cardiac functions in ASC therapy. In our work, we isolated human cardiac mesenchymal stromal cells (h-CMSCs) by means of three-dimensional organ culture (3D culture) during ex vivo expansion of cardiac tissue, to compare the functional efficacy with human bone-marrow derived mesenchymal stem cells (h-BM-MSCs), one of the actively studied ASCs. We characterized the h-CMSCs as CD90^low, c-kit^negative, CD105^positive phenotype and these cells express NANOG, SOX2, and GATA4. To identify the more effective type of EVs for angiogenesis among the different sources of ASCs, we isolated EVs which were derived from CMSCs with either normoxic or hypoxic condition and BM-MSCs. Our in vitro tube-formation results demonstrated that the angiogenic effects of EVs from hypoxia-treated CMSCs (CMSC-Hpx EVs) were greater than the well-known effects of EVs from BM-MSCs (BM-MSC EVs), and these were even comparable to human vascular endothelial growth factor (hVEGF), a potent angiogenic factor. Therefore, we present here that CD90^lowc-kit^negativeCD105^positive CMSCs under hypoxic conditions secrete functionally superior EVs for in vitro angiogenesis. Our findings will allow more insights on understanding myocardial repair.

• Journal of Life Science
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• v.19 no.6
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• pp.756-764
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• 2009

Scutellariae baicalensis GEORGt Acorus gramineus SOLAND and Gastrodia elata BLUME are traditional medicines used in the treatment of incipient stoke. In this study we investigated their effects on various aspects of neuronal differentiation in single or composite forms. Water-extracts of these medicines showed neuroprotective effects on cultured rat cortical neurons in normoxia and hypoxia. To understand the mechanism for neuroprotection we carried out various cell biological assays. They stimulated initial differentiation of neuronal development (transition from stage 1 to 2), and increased the number of spines and the length and number of dendritic processes. These effects were best manifested in the experimental group, which were given a mixture of the three kinds of extracts (p<0.01). To assess improvement of brain functions we carried out Morris water-maze tests for the mice that were fed on these extracts instead of water for 4 weeks. The experimental groups, especially those which were given the mixture of the three kinds of extract, showed significant (p<0.01) enhancement in memory as early as one day after the learning trial. These results indicate that these three kinds of extracts have synergistic effects on neuronal protection and improvement of brain functions.

• Journal of Medicine and Life Science
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• v.15 no.2
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• pp.67-71
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• 2018

Neuronal excitotoxicity induces mitochondrial dysfunction and the release of proapoptotic proteins. Excitotoxicity, the process by which the overactivation of excitatory neurotransmitter receptors leads to neuronal cell death. Neuronal death by excitotoxicity was related to neuronal degenerative disorders and hypoxia, results from excessive exposure to excitatory neurotransmitters, such as glutamate. Glutamate acts at NMDA receptors in cultured neurons to increase the intracellular free calcium concentration. Therefore endogenous glutamate may be a key factor to regulate neuronal cell death via activating $Ca^{2+}$ signaling. For this issue, we tested some conditions to alter intracellular $Ca^{2+}$ level in dissociated hippocampal neurons of rats. Cultured hippocampal neuron were treated by KCl (20 mM), $CaCl_2$ (3.8 mM) and glutamate ($5{\mu}M$) for 24 hrs. Interestingly, The Optical Density of hippocampal neurons was increased by high KCl application in MTT assay data. This enhanced response by high KCl was dependent on synaptic $Ca^{2+}$ influx but not on intracellular $Ca^{2+}$ level. However, the number of neurons seemed to be not changed in Hoechst 33342 staining data. These results suggest that enhancement of synaptic activity plays a key role to increase mitochondrial signaling in hippocampal neurons.

• Journal of Microbiology and Biotechnology
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• v.33 no.7
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• pp.864-874
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• 2023

Natural killer (NK) cell dysfunctions against hepatocellular carcinoma (HCC) in a hypoxic environment. Many solid tumors are present in a hypoxic condition, which changes the effector function of various immune cells. The transcription of hypoxic-inducible factors (HIFs) in cancer cells make it possible to adapt to their hypoxic environment and to escape the immune surveillance of NK cells. Recently, the correlation between the transcription of HIF-1α and pro-inflammatory cytokines has been reported. Interleukin (IL)-6 is higher in cancers with a highly invasive ability, and is closely related to the metastasis of cancers. This study showed that the expression of HIF-1α in HCC cells was associated with the presence of IL-6 in the environment of HCC-NK cells. Blocking of IL-6 by antibody in the HCC-NK interaction changed the production of several cytokines including TGF-β, IL-1, IL-18 and IL-21. Interestingly, in a co-culture of HIF-1α-expressed HCC cells and NK cells, blocking of IL-6 increased the production of IL-21 in their supernatants. In addition, the absence of IL-6 significantly enhanced the cytotoxic ability and the expression of the activating receptors (NKG2D, NKp44, and NKG2C) in NK cells to HIF-1α-expressed HCC cells. These effects might be made by the decreased expression of HIF-1α in HCC cells through the inhibited phosphorylation of STAT3. In conclusion, the absence of IL-6 in the interaction of HIF-1α-expressed HCC cells and NK cells could enhance the antitumor activity of NK cells to HCC cells.

• The Journal of Internal Korean Medicine
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• v.25 no.4
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• pp.324-336
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• 2004

Objectives : The purpose of this investigation is to evaluate the effects of Scutellaria baicalensis GEORGI on alteration in gene expression in a hypoxia model using cultured rat cortical cells. Methods : E18 rat cortical cells were grown in a Neurobasal medium containing B27 supplement. On 12 DIV, Scutellaria baicalensis GEORGI(20 ug/ml) was added to the culture media and left for 24 hrs. On 11 DIV, cells were given a hypoxic insult $(2%\;O_2/5%\;CO_2,\;37^{\circ}C,\;3\;hrs)$, returned to normoxia and cultured for another 24 hrs. Total RNA was prepared from Scutellaria baicalensis GEORGI-untreated (control) and -treated cultures and alteration in gene expression was analysed by microarray using rat 5K-TwinChips. Results : For most of the genes altered in expression, the Global M values were between -0.5 to +0.5. Among these, 1143 genes increased in their expression by more than Global M +0.1, while 1161 genes decreased by more than Global M -0.1. Effects on some of the genes whose functions are implicated in neural viability are as follows: 1) The expression of apoptosis-related genes such as Bad (Global M = 0.39), programmed cell death-2(Pdcd2) (Global M = 0.20) increased, while Purinergic receptor P2X(P2rxl) Global M = -0.22), Bc12-like1(Bc1211)(Global M = -0.19) decreased. 2) The expression of 'response to stress-related genes such as antioxidation-related AMP-activated protein kinase subunit gamma 1 gene (Prkag1) (Global M = 0.14), catalase gene (Global M = 0.14) and Heme Oxygenase(Hmoxl) increased. 3) The expression of Fos like antigen 2 (Fos12) expressed in neurons that survive ischemic insult increased (Global M = 0.97). Conclusions : these data suggest that Scutellaria baicalensis GEORGI increases the expression of antiapoptosis- and antioxidation- related genes in a way that can not yet be explained.

• The Korean Journal of Nuclear Medicine
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• v.9 no.2
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• pp.39-46
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• 1975

It is the purpose of this paper to design the most preferable method of erythropoietin bioassay in Korea. Bioassay utilizing polycythemic mice are currently in general use for the indirect determination of erythropoietin. Assay animals are usually prepared either by transfusion or by exposure to reduced oxygen tension in specially constructed chamber. We prepared the polycythemic, mice by the specially constructed hypobaric chamber. We observed weights and hematocrits of the mice in the hypobaric chamber, then hematocrits and 72 hours $^{59}Fe$ red cell upatke ratio of the polycythemic mice induced by hypoxia after removal from the hypobaric chamber. We designed the method of erythropoietin bioassay according to the results obtained by above experiments. Then we measured the 72 hours $^{59}Fe$ red cell uptake ratio of the polycythemic mice with normal saline, normal plasma and anemic plasma according to the method we designed. The results are followed: 1. The hematocrits of the mice in hypobaric chamber increased to 74% in 14 days It is preferable to maintain the pressure of the chamber to 400mmHg for first 4 days then 300mmHg for last 10 days to reduce the death rate and time consuming in hypobaric chamber. 2. After removal from the hypobaric chamber, the 72 hours $^{59}Fe$ red cell uptake ratio decreased rapidly and maintained the lowest level from the fourth day to tenth day. 3. We design the method of erythropoietin bioassay according to the results of above experiment and to the half life of erythropoietin. 4. The Korean product S9Fe is mixture of $^{59}Fe\;and\;^{55}Fe$. And the $^{59}Fe$ red cell uptake ratio in normal mice was far less with Korean product $^{59}Fe$ than with pure $^{59}Fe$ of foreign product. So it is desirable to use pure $^{59}Fe$ in this method of erythropoietin bioassay. 5. Considering the cost, the technique, the time consuming and the sensitivity it is the most preferable method of erythropoietin bioassay in Korea using hypobaric chamber to induce the polycythemia.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5043-5047
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• 2014

Nowadays increasing effectiveness in cancer therapy and investigation of formation of new strategies that enhance antiproliferative activity against target organs has become a subject of interest. Although the molecular mechanisms of apoptosis can not be fully explained, it is known that cell suicide program existing in their memory genetically is activated by pathophysiological conditions and events such as oxidative stress. Low pressure (hypobaric) conditions that create hypoxia promote apoptosis by inhibiting cell cycling. In this study, determination of the effects of fractional hypobaric applications at different times on HeLa cells at cellular and molecular levels were targeted. Experiments were carried out under hypobaric conditions (35.2 kPa) in a specially designed hypobaric cabin including 2% $O_2$ and 98% N. Application of fractional hypobaric conditions was repeated two times for 3 hours with an interval of 24 hours. At the end of the implementation period cells were allowed to incubate for 24 hours for activation of repair mechanisms. Cell kinetic parameters such as growth rate (MTT) and apoptotic index were used in determination of the effect of hypobaric conditions on HeLa cells. Also in our study expression levels of the Bcl-2 gene family that have regulatory roles in apoptosis were determined by the RT-PCR technique to evaluate molecular mechanisms. The results showed that antiproliferative effect of hypobaric conditions on HeLa cells started three hours from the time of application and increased depending on the period of exposure. While there was a significant decrease in growth rate values, there was a significant increase in apoptotic index values (p<0.01). Also molecular studies showed that hypobaric conditions caused a significant increase in expression level of proapoptotic gene Bax and significant decrease in antiapoptotic Bfl-1. Consequently fractional application of hypobaric conditions on HeLa cell cultures increased both antiproliferative and apoptotic effects and these effects were triggered by the Bax gene.

• Journal of Radiation Protection and Research
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• v.43 no.2
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• pp.66-74
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• 2018

Background: Tumor response to anticancer therapies can much be influenced by microenvironmental factors. In this study, we determined the effect of these microenvironmental factors on DNA methylation using A549 human lung adenocarcinoma cell line. Materials and Methods: We subjected A549 cells to various conditions mimicking tumor microenvironment including hypoxia, acidosis (sodium lactate), oxidative stress ($H_2O_2$), bystander effect (supernatant from doxorubicin (Dox)-treated or irradiated cells), and immune cell infiltration (supernatant from THP-1 or Jurkat T cells). Genomic DNA was isolated from these cells and analyzed for DNA methylation. Clonogenic cell survival, gene expression, and metabolism were analyzed in cells treated with some of these conditions. Results and Discussion: We found that DNA methylation level was significantly decreased in A549 cells treated with conditioned media from Dox-treated cells or Jurkat T cells, or sodium lactate, indicating an active transcription. To determine whether the decreased DNA methylation affects radiation sensitivity, we exposed cells to these conditions followed by 6 Gy irradiation and found that cell survival was significantly increased by sodium lactate while it was decreased by conditioned media from Dox-treated cells. We further observed that cells treated with conditioned media from Dox-treated cells exhibited significant changes in expression of genes including BAX and FAS (involved in apoptosis), NADPH dehydrogenase (mitochondria), EGFR (cellular survival) and RAD51 (DNA damage repair) while sodium lactate increased cellular metabolism rather than changing the gene expression. Conclusion: Our results suggest that various tumor microenvironmental factors can differentially influence DNA methylation and hence radiosensitivity and gene expression in A549 cancer cells.

• Clinical and Experimental Pediatrics
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• v.50 no.7
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• pp.686-693
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• 2007

Purpose : Mycophenolic acid (MPA), the active metabolite of mycophenolate mofetil (MMF), is a potent inhibitor of inosine-monophosphate dehydrogenase (IMPDH), a new immunosuppressive drug used. It was reported that MPA protected neurons after excitotoxic injury, induced apoptosis in microglial cells. However, the effects of MPA on hypoxic-ischemic (HI) brain injury has not been yet evaluated. Therefore, we examined whether MPA could be neuroprotective in perinatal HI brain injury using Rice-Vannucci model (in vivo) and in rat brain cortical cell culture induced by hypoxia (in vitro). Methods : Cortical cells were cultured using a 18-day-pregnant Sprague-Dawley (SD) rats and incubated in 1% $O_2$ incubator for hypoxia. MPA ($10{\mu}g/mL$) before or after a HI insult was treated. Seven-day-old SD rat pups were subjected to left carotid occlusion followed by 2 hours of hypoxic exposure (8% $O_2$). MPA (10 mg/kg) before or after a HI insult were administrated intraperitoneally. Apoptosis was measured using western blot and real-time PCR for Bcl-2, Bax, caspase-3. Results : H&E stain revealed increased brain volume in the MPA-treated group in vivo animal model of neonatal HI brain injury. Western blot and real-time PCR showed the expression of caspase-3 and Bax/Bcl-2 were decreased in the MPA-treated group In in vitro and in vivo model of perinatal HI brain injury, Conclusion : These results may suggest that the administration of MPA before HI insult could significantly protect against perinatal HI brain injury via anti-apoptotic mechanisms, which offers the possibility of MPA application for the treatment of neonatal HI encephalopathy.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.317-325
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• 2006

Purpose : This study was carried out to elucidate the effects of nitric oxide synthase(NOS) inhibitor, NG-monomethyl-L-arginine(L-NMMA) and nitric oxide precursor, L-arginine(L-Arg) on cerebral hemodynamics and energy metabolism during reoxygenation-reperfusion(RR) after hypoxia-ischemia(HI) in newborn piglets. Methods : Twenty-eight newborn piglets were divided into 4 groups; Sham normal control(NC), experimental control(EC), L-NMMA(HI & RR with L-NMMA), and L-Arg(HI & RR with L-Arg) groups. HI was induced by occlusion of bilateral common carotid arteries and simultaneously breathing with 8 percent oxygen for 30 mins, and followed RR by release of carotid occlusion and normoxic ventilation for one hour. All groups were monitored with cerebral hemodynamics and cytochrome $aa_3$ (Cyt $aa_3$) using near infrared spectroscopy(NIRS). $Na^+$, $K^+$-ATPase activity, lipid peroxidation products, and tissue high energy phosphate levels were determined biochemically in the cerebral cortex. Results : In experimental groups, mean arterial blood pressure, $PaO_2$, and pH decreased, and base excess and blood lactate level increased after HI compared to NC group(P<0.05). These variables subsequently returned to baseline after RR except pH. There were no differences among the experimental groups. In NIRS, oxidized hemoglobin($HbO_2$) decreased and hemoglobin(Hb) increased during HI(P<0.05) but returned to base line immediately after RR; 40 min after RR, the $HbO_2$ had decreased significantly compared to NC group(P<0.05). Changes of Cyt $aa_3$ decreased significantly compared to NC after HI and recovered at the end of the experiment. Significantly reduced cerebral cortical cell membrane $Na^+$, $K^+$-ATPase activity and increased lipid peroxidation products(P<0.05) were not improved with L-NMMA or L-Arg. Conclusion : These findings suggest that NO is not involved in the mechanism of HI and RR brain damage during the early acute phase of RR.