Biomedical subjects

Wang Jae Lee

Publications and source records attributed to Wang Jae Lee.

At least 19 recordsLinked to original sources

PubMed2006

Stage-specific expression of two neighboring Crlz1 and IgJ genes during B cell development is regulated by their chromatin accessibility and histone acetylation.

The IgJ gene is expressed in the plasma cell stage. However, its neighboring charged amino acid-rich leucine zipper 1 (Crlz1) gene, which is mapped 30 kb upstream of the IgJ gene in mice, is shown to be expressed in the pre-B cell stage. These stage-specific expressions of two neighboring genes are found to be regulated by their chromatin accessibility and acetylation. Hypersensitive site 1 on the IgJ promoter is opened in the plasma cells, whereas hypersensitive sites 9/10 on the Crlz1 promoter are opened in the pre-B cells. Furthermore, H3 and H4 histones toward the chromatin of the Crlz1 gene are found to be hyperacetylated, especially on H3, in the pre-B cells, whereas those toward the chromatin of the IgJ gene are found to be hyperacetylated in the plasma cells. Consistently, the hyperacetylation of H3 and H4 toward the chromatin of the IgJ gene but not the Crlz1 gene is induced by an IL-2 treatment of BCL1, which is a model cell line for studying the terminal differentiation of B cells.

Acetylation↗

PubMed2006

Regulation of UVB-induced IL-8 and MCP-1 production in skin keratinocytes by increasing vitamin C uptake via the redistribution of SVCT-1 from the cytosol to the membrane.

It is well known that UVB (290-320 nm) induces inflammation in skin by the transcription and release of cytokines and chemokines from skin keratinocytes. In addition, it is considered that intracellular reactive oxygen species (ROS) plays an important role in UVB-induced inflammatory response in the skin. Therefore, we investigated the effect of vitamin C, a potent antioxidant, on the regulation of UVB-induced skin inflammation via the modulation of chemokines production. Vitamin C uptake into keratinocytes is increased by UVB irradiation in a time- and dose-dependent manner through the translocation of sodium-dependent vitamin C transporter-1 (SVCT-1), a vitamin C-specific transporter, from the cytosol to the membrane. To evaluate the effect of vitamin C on the chemokine mRNA expression, we performed RNase protection assay. As a result, there was a remarkable change in chemokine mRNA expression, especially IL-8 and monocyte chemoattractant protein (MCP)-1 expression. In addition, increased IL-8 and MCP-1 mRNA expressions were suppressed by vitamin C treatment. We also confirmed the results of protein levels measured by ELISA. Taken together, vitamin C uptake is increased in UVB-irradiated keratinocytes through the translocation of SVCT-1 and regulates inflammatory response in the skin via the downregulation of IL-8 and MCP-1 production.

Antioxidants↗

PubMed2006

Ligation of centrocyte/centroblast marker 1 on Epstein-Barr virus--transformed B lymphocytes induces cell death in a reactive oxygen species--dependent manner.

After primary infection of B cells with Epstein-Barr virus (EBV), infected B cells express several viral homologs of human genes that promote activation (LMP1 and CD40) or survival (BHRF and BCL2). EBV-infected B cells also express germinal center phenotype markers, such as CD77, PNA, CD95, and CD38. This transformation of B cells by EBV infection resembles normal B-cell activation and differentiation arising in the germinal center. In the present study, we found that EBV-transformed B cells expressed centrocyte/centroblast marker 1 (CM1), a possible marker of GC B cells and an inducer of their apoptosis. Moreover, ligation of CM1 on EBV-transformed B cells by immobilized anti-CM1 monoclonal antibody induced cell death. The ligation of CM1 immediately increased the generation of intracellular reactive oxygen species (ROS) and disrupted the mitochondrial membrane potential. Pretreatment with N-acetyl cystein (an ROS inhibitor) almost completely blocked this cell death, but Z-VAD-fmk (a caspase inhibitor) did not. We further investigated whether apoptosis-inducing factor (AIF) and endonuclease G (EndoG), which are both related to caspase-independent cell death, would be translocated to the nucleus during the ligation of CM1. We found that AIF and EndoG were released to the cytosplam but not translocated to the nucleus. Moreover, cytochalasin D, a cytoskeleton disruptor, rescued the cells from CM1-mediated cell death and blocked ROS generation. Therefore, it is conceivable that CM1 signaling might provoke cytoskeleton polymerization and trigger ROS generation. Taking these observations together, we conclude that the ligation of CM1 on EBV-transformed B cells can cause cell death via the ROS produced by F-actin polymerization in a caspase-independent manner, although this cell death might be unrelated to AIF and EndoG release from the mitochondria.

Acetylcysteine↗

PubMed2006

Immunohistochemical localization of sodium-dependent L-ascorbic acid transporter 1 protein in rat kidney.

Recently, two L-ascorbic acid transporters were identified; sodium-dependent vitamin C transporter (SVCT) 1 and SVCT2. The previous study suggested that SVCT protein might be present on the apical membrane in the straight segment (S3) of proximal tubule. In the present study, SVCT1 immunoreactivity (IR) was observed in the brush border of proximal straight tubules in the medullary ray of renal cortex and the outer stripe of outer medulla, while SVCT2 IR was not localized in any region of the kidney. Since the mechanism of VC reabsorption in the kidney has not been fully elucidated up to the present time, it is meaningful to demonstrate the exact cellular distribution of SVCT protein in the kidney.

Animals↗

PubMed2006

Immunohistochemical study of the distribution of sodium-dependent vitamin C transporters in adult rat brain.

Sodium-dependent vitamin C transporters (SVCTs) is known to transport the reduced form of ascorbic acid into the cell, whereas the oxidized form of vitamin C (VC) is moved through a facilitative sugar transporter, such as glucose transporter (GLUT). With regard to the distribution of SVCT1 and -2 within the various organs, they were reported to be expressed in different types of cells. Especially in the central nervous system, only SVCT2 mRNA was expressed mainly in neurons and some types of neuroglial cells. However, data on the expression of SVCT proteins in the brain are scant. Therefore, we tried to develop comprehensive data on the distribution of SVCT proteins in adult rat brain by using immunohistochemical techniques for the first time. In our study, SVCT2 immunoreactivities (IRs) were intensely localized in the neurons of cerebral cortex, hippocampus, and Purkinje cells of cerebellum, and much weaker SVCT2 IRs were found in the other brain regions. Judging from double-immunohistochemical data, most of the cells expressing SVCT2 IRs were likely to be neurons or microglia, even though the cells in choroids plexus or ependymal cells around the ventricles also exhibited SVCT2 IRs. Complete mapping of the distribution of SVCT2 IRs was available by using a semiquantitative method. The subcellular localization of SVCT proteins is necessary for understanding the exact role of the protein, so the current overall mapping of SVCT IRs in the rat brain could be the basis for further studies on related subjects.

Animals↗

PubMed2006

UVB-induced interleukin-18 production is downregulated by tannic acids in human HaCaT keratinocytes.

Tannic acids (TAs) are believed to be the key active components in plants, and are believed to be responsible for their anti-inflammatory, anti-viral effects and chemoprevention of cancer. However, the molecular mechanisms for the action of TA are unclear. This study examined the effects of TA on cutaneous inflammation with a human keratinocyte cell line (HaCaT). Interleukin-18 (IL-18) has multiple effects upon various cells involved in inflammatory response. In this study, the IL-18 mRNA expression and protein levels were reduced by a TA pretreatment. UV radiation can trigger the induction of the p38 mitogen-activated protein kinase (MAPK)-dependent signalling cascade. Immunoprecipitation and Western blot analysis was performed to determine if TA regulate the MAPK signalling pathway. TA significantly inhibited the activation of p38 MAPK and extracellular signal-regulated protein kinases. Moreover, TA-inhibited UVB enhanced the expression of the inflammatory mediators, IL-1, IL-6, tumor necrotic factor-alpha, cyclooxygenase-2 and prostaglandin E(2) in UVB-irradiated HaCaT cells. The topical application of TA on mouse skin treated with UVB irradiation has shown that TA inhibited the formation of erythema. These findings suggest that TA has significant anti-inflammatory effects on the UVB-induced response on the skin and may be a candidate natural compound for the regulation of cutaneous inflammation.

Animals↗

PubMed2005

Immunohistochemical study on the distribution of sodium-dependent vitamin C transporters in the respiratory system of adult rat.

As vitamin C (L-ascorbic acid, VC) is known to be essential for many enzymatic reactions, the study on the transport mechanism of VC through cytoplasmic membrane is crucial to understanding physiological role of VC in cells and the respiratory system. In this regard, the study on the newly identified sodium-dependent VC transporters (SVCTs), SVCT1 and SVCT2, is required in organs that contain high concentration of VC. We have shown the distribution of SVCT proteins in the respiratory system, which has been reported to be one of the organs with a high concentration of VC, using immunohistochemical techniques. In the present study, intense SVCT immunoreactivities (IRs) were mainly localized in the respiratory system epithelial cells. In the trachea, both SVCT1 and 2 were localized in the psuedostratified ciliated columnar epithelium. In the terminal bronchiole, SVCT1 and 2 IRs were mainly observed in the apical portion of the simple columnar epithelium. In addition, SVCT IRs was localized within the cell membrane of some alveolar cells, even though we could not identify the exact cell types. These results provide the first evidence that intense SVCT1 and 2 IRs were found in the apical portion of the respiratory epithelial cells, suggesting that SVCT proteins in the apical portion could transport the reduced form of VC included in the airway surface liquid into the respiratory epithelial cells.

Animals↗

PubMed2005

Mega-dose Vitamin C modulates T cell functions in Balb/c mice only when administered during T cell activation.

Previously we reported that a mega-dose of Vitamin C enhanced the initial stage of delayed-type hypersensitivity reaction in Balb/c mice. In this study its effects were further evaluated as follows. Mice were administered Vitamin C intraperitoneally at 0.625 mg/day or at 5mg/day for variable days before, during, or after being sensitized with DNFB. T cells were isolated in each group and examined. When stimulated antigen-specifically or non-specifically in vitro, mice showed elevated thymidine uptake and a shift of cytokine secretion profiles toward Th1, i.e., elevated levels IL-2, TNF-alpha, and IFN-gamma, and lowered level of the Th2 cytokine IL-4, only when Vitamin C was administered during sensitization. T cells from those mice administered Vitamin C before sensitization or after challenge showed the same T cell properties as those from PBS-treated mice. Mice were also given 0.625 mg/day of Vitamin C during primary and/or secondary immunizations with KLH and secondary specific antibody titers in sera were measured. The total specific antibody titer was lowered in Vitamin C-treated animals whenever treatments were administered, and this was entirely attributed to decreased levels of IgG1 and IgE antibodies. Based on these results, we suggest that an exogenously administered mega-dose of Vitamin C shifts immunity in Balb/c mouse toward Th1 and that these affects occur only when Vitamin C is administered during T cell activation.

Animals↗

PubMed2005

IL-18 enhances SCF production of melanoma cells by regulating ROI and p38 MAPK activity.

It has been reported that interleukin-18 (IL-18) is secreted by B16 murine melanoma cells and that this endogenous IL-18 is involved in the immune escape of murine melanoma cells. The present study investigated whether interleukin (IL)-18 can regulate stem cell factor (SCF) expression, known to be associated with melanocyte proliferation, in B16F10 murine melanoma cells. SCF expression was examined by RT-PCR, intracellular FACS analysis, and ELISA in IL-18 antisense transfectants. Transfection with IL-18 antisense cDNA reduced SCF expression and the expression was enhanced by addition of exogenous IL-18. In addition, the effect of IL-18 was blocked by the antioxidant, N-acetyl-L-cysteine (NAC), indicating that IL-18 regulates ROI production, which is involved in SCF production. Furthermore, inhibitors of p38 mitogen-activated protein kinase (MAPK), such as SB203580, blocked enhanced SCF expression, indicating that p38 MAPK activity is required for IL-18-enhanced SCF production. Taken together, these results suggest that IL-18 plays a critical role as a regulatory factor of SCF expression via ROI and p38 MAPK activity in B16F10 murine melanoma cells.

Animals↗

PubMed2005

Sodium ascorbate (vitamin C) induces apoptosis in melanoma cells via the down-regulation of transferrin receptor dependent iron uptake.

Sodium ascorbate (vitamin C) has a reputation for inconsistent effects upon malignant tumor cells, which vary from growth stimulation to apoptosis induction. Melanoma cells were found to be more susceptible to vitamin C toxicity than any other tumor cells. The present study has shown that sodium ascorbate decreases cellular iron uptake by melanoma cells in a dose- and time-dependent fashion, indicating that intracellular iron levels may be a critical factor in sodium ascorbate-induced apoptosis. Indeed, sodium ascorbate-induced apoptosis is enhanced by the iron chelator, desferrioxamine (DFO) while it is inhibited by the iron donor, ferric ammonium citrate (FAC). Moreover, the inhibitory effects of sodium ascorbate on intracellular iron levels are blocked by addition of transferrin, suggesting that transferrin receptor (TfR) dependent pathway of iron uptake may be regulated by sodium ascorbate. Cells exposed to sodium ascorbate demonstrated down-regulation of TfR expression and this precedes sodium ascorbate-induced apoptosis. Taken together, sodium ascorbate-mediated apoptosis appears to be initiated by a reduction of TfR expression, resulting in a down-regulation of iron uptake followed by an induction of apoptosis. This study demonstrates the specific mechanism of sodium ascorbate-induced apoptosis and these findings support future clinical trial of sodium ascorbate in the prevention of human melanoma relapse.

Animals↗

PubMed2004

Increased expression of IL-18 in cutaneous graft-versus-host disease.

Interleukin-18 (IL-18) is an 18-kDa cytokine produced by lipopolysaccharide (LPS)-activated macrophages or Kupffer cells. In addition, IL-18 is also produced by many different types of cells and tissues, including epidermal keratinocytes, the adrenal cortex, and the brain. IL-18 acts on the immune system to increase IFN-gamma production from T and NK cells to enhance NK cell cytotoxicity and to activate Th1 cell proliferation. It is considered that the tissue expression of cytokines and cell adhesion molecules such as ICAM-1 are common in graft-versus-host disease (GVHD). Recent evidence suggests that IL-18 is a cytokine relevant in the pathogenesis of GVHD. Despite the potential importance of IL-18 in GVHD, the distribution of IL-18 production in cutaneous GVHD has not been fully investigated. In this study, the expression of IL-18 in the cutaneous GVHD was investigated. Formalin-fixed, paraffin-embedded tissue sections were obtained, and immunohistochemical analysis was performed to detect IL-18 and ICAM-1 expression according to the acute and chronic GVHD. Immunohistochemical analysis confirmed the enhanced IL-18 expression levels in the early stage (grade 1) of acute GVHD and the late stage (sclerodermoid) of chronic GVHD compared to the other stages. In contrast, the ICAM-1 expression level was constant at all stages. Our findings indicate that IL-18 is a significant pathogenic indicator in cutaneous GVHD, and the tissue expression of IL-18 seems to be associated with the pathogenesis of acute and chronic GVHD.

Chronic Disease↗

PubMed2004

Alpha-synuclein induces apoptosis by altered expression in human peripheral lymphocyte in Parkinson's disease.

Though the etiology of Parkinson's disease (PD) remains unclear, alpha-synuclein (alpha-SN) is regarded as a major causative agent of PD. Several lines of evidence indicate that immunological abnormalities are associated with PD for unknown reasons. The present study was performed to assess whether peripheral blood mononuclear cells (PBMCs) show altered alpha-SN expression in PD patients and to identify its functions, which may be related to peripheral immune abnormalities in PD. alpha-SN was found to be expressed more in 151 idiopathic PD (IPD) patients than in 101 healthy controls, who nevertheless showed as age-dependent increases. By in vitro transfection, alpha-SN expression was shown to be correlated with glucocorticoid sensitive apoptosis, possibly caused by the enhanced expression of glucocorticoid receptor (GR), caspase activations (caspase-8, caspase-9), CD95 up-regulation, and reactive oxygen species (ROS) production. An understanding of the correlation between alpha-SN levels and apoptosis in the presence of the coordinated involvement of multiple processes would provide an insight into the molecular basis of the disease. The present study provides a clue that the alpha-SN may be one of the primary causes of the immune abnormalities observed in PD and offers new targets for pharmacotherapeutic intervention.

Apoptosis↗

PubMed2004

Resistance to cytotoxic chemotherapy is induced by NK cells in non-Hodgkin's Lymphoma Cells.

It is known that B lymphoma cells are sensitive to cytotoxic chemotherapy, but primary or secondary chemoresistance frequently occurs and is the major cause of death in these patients. However, the mechanisms by which lymphoma cells acquire resistance to cytotoxic drugs are not fully understood. Recently, it was reported that B cells secrete immunoglobulin and produce cytokines after interacting with NK cells, thus indicating the importance of NK/B interactions. In this study, we investigated the mechanism of resistance to cytotoxic chemotherapy induced in cocultures of NK cells and Raji cells. Normally, Raji cells are doxorubicin-sensitive, but Raji cells cocultured with NK cells become doxorubicin-resistant. In addition, we detected the upregulation of CD69 and CD70 on Raji cells cocultured with NK cells, suggesting that Raji cells are activated by NK cells. We also found that the resistance of Raji cells to doxorubicin increased when they had been treated with NK cell coculture supernatant. Furthermore, boiled culture supernatant did not inhibit doxorubicin-mediated cell death, indicating that soluble factors are involved. Finally, we confirmed that NK cells produce TNF alpha, and that doxorubicin-sensitive Raji cells become doxorubicin-resistant after TNF alpha treatment. Taken together, these results suggest that B lymphoma cell resistance to doxorubicin-mediated cell death is induced by coculture with NK cells, because of TNF alpha secretion.

Antibiotics, Antineoplastic↗

PubMed2003

L-ascorbic acid (vitamin C) induces the apoptosis of B16 murine melanoma cells via a caspase-8-independent pathway.

L-ascorbic acid (vitamin C) has been reported to play a role in the treatment and prevention of cancer. However, its specific mechanistic pathways remain obscure. This study was carried out to identify the sodium ascorbate-induced apoptotic pathway in B16F10 murine melanoma cells. Sodium ascorbate was found to induce the apoptosis of B16F10 murine melanoma in a time- and dose-dependent manner, and this was prevented by pretreatment with N-acetyl- L-cysteine (NAC), a well-known antioxidant. In fact, sodium ascorbate-treated B16F10 melanoma cells showed increased intracellular reactive oxygen species generation (ROS) levels. These results indicate that sodium ascorbate induced apoptosis in B16F10 murine melanoma cells by acting as a prooxidant. We examined the involvement of caspase-8 using a specific caspase-8 inhibitor (z-IETD-fmk) on the sodium ascorbate-induced apoptotic pathway. Cell death was found not to be inhibited by z-IETD-fmk treatment, indicating that sodium ascorbate-induced apoptosis is not mediated by caspase-8. In addition, we detected a reduction in the mitochondrial membrane potential during apoptosis and confirmed cytochrome-c release from mitochondria by immunoblotting. Taken together, it appears that the induction of a prooxidant state by sodium ascorbate and a subsequent reduction in mitochondrial membrane potential are involved in the apoptotic pathway of B16F10 murine melanoma cells, and that this occurs in a caspase-8-independent manner.

Animals↗

PubMed2003

The correspondence between the labeling patterns of antibody RT97, neurofilaments, microtubule associated protein 1B and tau varies with cell types and development stages of chicken retina.

The correspondence between the labeling patterns of antibody RT97, neurofilaments (NF-M and NF-H), microtubule associated protein 1B (MAP1B) and tau, were studied in the developing chicken. At embryonic day 3 (E3), intense RT97 immunoreactivity (IR) was found to be localized in cells in the region adjacent to the intraretinal space, which separates the inner and outer layers of the optic cup, and this was sustained at E8. However, this pattern changed dramatically at E12, as the intensities of RT97 IR increased in the inner retinal layer, while the outermost layers showed only weak IR. The adult stage retina showed RT97 IR within the nerve fibers of the ganglion cells, the processes of the amacrine cells and the photoreceptors. Additional immunostainings for NF-M, -H, MAP1B and tau showed that the observed changes in RT97 IRs were due to the different expressions of these proteins at different development stages.

Animals↗

PubMed2003

Caveolin-3 expression during early chicken development.

Caveolin-3, a protein that is correlated with caveolae, is found in muscle cells, especially during their differentiation. Although the distribution of caveolin-3 has been studied in cases such as adult and late embryonic mammalians, the expression of caveolin-3 has not been clearly defined during chicken development. In this study, we detected intense caveolin-3 immunoreactivity (IR) as early as embryonic day 4 (E4), most of the signals were localized within the neural tube and myotome. While IRs in the brain occurred in radial glia at E6, these intensities were reduced to an almost undetectable level at E8. In the case of muscle cells, the exclusive localization of caveolin-3 in the cytoplasmic membrane was detected even at E11, much earlier than in mammalian muscle tissues. Although the caveolin-3 IR pattern was similar to that reported by previous studies, we found some interesting mismatches in the case of avian tissues. Although we are unable to explain caveolin-3 expression patterns in the early embryonic stages, this study could provide a basis for further study on the function of caveolin-3 in avian embryogenesis.

Animals↗

PubMed2003

Vitamin C downregulates interleukin-18 production by increasing reactive oxygen intermediate and mitogen-activated protein kinase signalling in B16F10 murine melanoma cells.

We recently reported that interleukin-18 (IL-18) is highly expressed in malignant skin tumours such as melanomas, and may play a key role in the malignancy of such tumours. This study was designed to investigate the mechanisms of IL-18 regulation by vitamin C in B16F10 murine melanoma cells. Cells were treated with vitamin C, and the expression of IL-18 was measured by reverse transcription-polymerase chain reaction and intracellular flow cytometry analysis. Decreased IL-18 production and a significant reduction in IL-18 mRNA transcript were detected in cells treated with vitamin C. The effect of vitamin C treatment was blocked by the antioxidant N-acetyl-L-cysteine, suggesting that vitamin C affects IL-18 expression by up-regulating intracellular reactive oxygen intermediate (ROI) levels. To investigate whether the mitogen-activated protein kinase (MAPK) signalling pathway is involved in the downregulation of IL-18 production, cells were pretreated with SB203580, an inhibitor of p38 MAPK, prior to the addition of vitamin C. This pretreatment blocked the decrease in IL-18 production. However, vitamin C treatment enhanced the expression of phosphorylated p38 MAPK. Taken together, we conclude that vitamin C increases intracellular ROI levels, and regulates IL-18 production through the MAPK signalling pathway.

Acetylcysteine↗

PubMed2002

The enhanced IL-18 production by UVB irradiation requires ROI and AP-1 signaling in human keratinocyte cell line (HaCaT).

Based on our recent observation that enhanced IL-18 expression positively correlates with malignant skin tumors, such as SCC and melanoma, we examined the possible role of UVB, known to be associated with skin cancer development, in the enhancement of IL-18 production using primary human epidermal keratinocytes and human keratinocyte cell line HaCaT. After cells were exposed to UVB irradiation in vitro, IL-18 production was examined by Northern blot analysis and ELISA, and it was found that IL-18 production is enhanced by UVB irradiation in a dose- and time-dependent manner. In addition, we confirmed that it is functionally active form of IL-18 using the inhibitor of caspase-1. The effect of UVB irradiation was blocked by antioxidant, N-acetyl-L-cysteine (NAC), which suggested the involvement of reactive oxygen intermediates (ROI) in the signal transduction of UVB irradiation-enhanced IL-18 synthesis. We also found that UVB irradiation increased AP-1 binding activity by using EMSA with AP-1-specific oligonucleotide. Furthermore, inhibitors of UVB-induced AP-1 activity, such as PD98059, blocked enhanced IL-18 production, indicating that AP-1 activation is required for UVB-induced IL-18 production. Taken together, our results suggest that UVB irradiation-enhanced IL-18 production is selectively mediated through the generation of ROI and the activation of AP-1.

Cell Line↗