Biomedical subjects

H R Kim

Publications and source records attributed to H R Kim.

At least 37 records · Page 2Linked to original sources

PubMed2001

Sodium nitroprusside enhances TRAIL-induced apoptosis via a mitochondria-dependent pathway in human colorectal carcinoma CX-1 cells.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL, Apo-2L) is a recently characterized member of the family of programmed cell death-inducing ligands that includes TNF-alpha and CD95L (FasL). It is well known that TRAIL binds to the death signaling receptors, DR4 and DR5, and initiates the TRAIL death pathway. Activation of this pathway, mediated through a caspase cascade, causes apoptosis. In this study, we hypothesized that oxidative stress facilitates TRAIL-induced apoptosis by promoting caspase activity through cytochrome c release from mitochondria. Human colorectal carcinoma CX-1 cells were treated with various concentrations of TRAIL (12.5-200 ng/ml) and/or sodium nitroprusside (SNP; 0.03-1 mM) for 12 h. SNP, a nitric oxide donor, which had little toxic effect by itself, enhanced TRAIL-induced cytotoxicity. For example, TRAIL-induced apoptosis (200 ng/ml) was increased by a factor of 2.5-fold in the presence of 1 mM SNP. The combined treatment also caused an increase in cytochrome c release, caspase-3 activity, and PARP cleavage. Overexpression of Bcl-2 completely blocked the SNP-promoting effects, but only moderately inhibited TRAIL-induced apoptosis. Similar results were observed in the presence of hydrogen peroxide or peroxynitrite. Taken together, the present studies suggest that SNP enhances TRAIL-induced cytotoxicity by facilitating the mitochondria-mediated caspase signal transduction pathway.

Apoptosis↗

PubMed2001

Antiosteoporotic activity of Dae-Bo-Won-Chun in ovariectomized rats.

The preventive effect of the herbal formulation, "Dae-Bo-Won-Chun" (DBWC), on the progress of bone loss induced by ovariectomy (OVX) was studied in rats. From light microscope analyses, porous or erosive appearances were observed on the surface of trabecular bone of tibia in ovariectomized rats, whereas those of the same bone in sham-operated rats were composed of fine particles. The trabecular bone area and trabecular thickness in ovariectomized rats decreased by 50% from those in sham-operated rats, these decreases were completely inhibited by administration of DBWC at a concentration of 10 mg/kg per day for 7 weeks. The mechanical strength of the neck of the femur was decreased by ovariectomy, and this was significantly suppressed by the administration of DBWC. Serum phosphorus, alkaline phosphatase and thyroxine levels in ovariectomized rats increased compared with those in sham-operated rats, and increases were completely inhibited by the administration of DBWC. These results strongly suggest that DBWC is effective in preventing the development of bone loss induced by ovariectomy in rats.

Animals↗

PubMed2001

A framework for sequencing the rice genome.

Rice is an important food crop and a model plant for other cereal genomes. The Clemson University Genomics Institute framework project, begun two years ago in anticipation of the now ongoing international effort to sequence the rice genome, is nearing completion. Two bacterial artificial chromosome (BAC) libraries have been constructed from the Oryza sativa cultivar Nipponbare. Over 100,000 BAC end sequences have been generated from these libraries and, at a current total of 28 Mbp, represent 6.5% of the total rice genome sequence. This sequence information has allowed us to draw first conclusions about unique and redundant rice genomic sequences. In addition, more than 60,000 clones (19 genome equivalents) have been successfully fingerprinted and assembled into contigs using FPC software. Many of these contigs have been anchored to the rice chromosomes using a variety of techniques. Hybridization experiments have shown these contigs to be very robust. Contig assembly and hybridization experiments have revealed some surprising insights into the organization of the rice genome, which will have significant repercussions for the sequencing effort. Integration of BAC end sequence data with anchored contig information has provided unexpected revelations on sequence organization at the chromosomal level.

Chromosome Mapping↗

PubMed2001

Cloning and expression of a ferritin subunit for Galleria mellonella.

Ferritin was purified from iron-fed Galleria mellonella hemolymph by ultra centrifugation and FPLC (Superose 6). SDS-PAGE revealed three bands of 26, 30, and 32 kDa. The ferritin 26 kDa subunit cDNA was obtained from RT-PCR using primer designed from N-terminal sequence analysis. 5'-RACE was used to obtain the complete protein coding sequence. The sequence encodes a 211 amino acid polypeptide including a 20 amino acid leader peptide. An IRE (iron-responsive element) sequence with a predicted stem-loop structure was present in the 5'-UTR of ferritin mRNA. Sequence alignment has a sequence identity with Calpodes ethlius (S)(74%), Drosophila melanogaster (50%), and Aedes aegypti (39%). Northern blot analysis indicated that there were 1.5- and 1.75-fold increases in the expression of ferritin mRNA after iron-fed fat body and midgut, respectively. Also, we confirmed that the ferritin mRNA is not expressed in adult ovary and testis. Arch.

Amino Acid Sequence↗

PubMed2001

Inhibitory effect on immunoglobulin E production in vivo and in vitro by Siegesbeckia glabrescens.

Elevated levels of immunoglobulin (Ig)E are associated with immediate-type allergic reactions. The effect of an aqueous extract of Siegesbeckia glabrescens (Compositae) whole plants (SGWP) on in vivo and in vitro IgE production was studied in mice. SGWP dose-dependently inhibited the active systemic anaphylaxis and serum IgE production induced by immunization with ovalbumin and Bordetella pertussis toxin absorbed to aluminium hydroxide gel. SGWP dose-dependently inhibited IL-4-dependent IgE production by lipopolysaccharide-stimulated murine whole spleen cells. In the case of U266 human IgE-bearing B cells, SGWP also showed an inhibitory effect on IgE production. These results suggest that SGWP has an anti-allergic activity by inhibiting IgE production from B cells.

Anaphylaxis↗

PubMed2001

Blockade of the p38 mitogen-activated protein kinase pathway inhibits inducible nitric oxide synthase and interleukin-6 expression in MC3T3E-1 osteoblasts.

Treatment of MC3T3E-1 osteoblast cultures with combined interferon- gamma(IFN- gamma), lipopolysaccharide (LPS) and tumor necrosis factor- alpha(TNF- alpha) induces expressions of inducible nitric oxide synthase (iNOS) and interleukin-6 (IL-6), resulting in sustained releases of large amounts of nitric oxide and IL-6. However IFN- gamma, LPS and TNF- alpha individually induces non-detectable or small amounts of NO and IL-6 in MC3T3E-1 osteoblasts. The role of mitogen-activated protein kinase (MAPK) activation in the early intracellular signal transduction involved in iNOS and IL-6 transcription in the combined agents-stimulated osteoblasts has been investigated. The p38 MAPK pathway is specifically involved in the combined agents-induced NO and IL-6 release, since NO and IL-6 release in the presence of a specific inhibitor of p38 MAPK, 4-(4-fluorophenyl)-2-(4-metylsulfinylphenyl)-5-(4-pyridyl)imidazole (SB203580), are significantly diminished. In contrast, PD98059, a specific inhibitor of MEK1, had no effect on NO and IL-6 release. Northern blot analysis showed that the p38 MAPK pathway controlled iNOS and IL-6 transcription levels. These data suggest that p38 MAPK plays an important role in the secretion of NO and IL-6 in LPS/IFN- gamma or TNF- alpha /IFN- gamma -treated MC3T3E-1 osteoblasts.

Animals↗

PubMed2001

Inhibition of immunologic and nonimmunologic stimulation-mediated anaphylactic reactions by water extract of white eggplant (Solanum melongena).

We investigated the effect of water extract of Solanum melongena(SMWE) on immunologic and nonimmunologic stimulation-mediated anaphylactic reactions. Nonimmunologic anaphylactic reaction was induced by compound 48/80 injection. Oral administration of SMWE (1 g kg(-1)) completely inhibited compound 48/80-induced anaphylactic reaction. Immunologic anaphylactic reaction was generated by sensitizing the skin with anti-dinitrophenyl (DNP) IgE followed 48 h later with an injection of antigen. Oral administration of SMWE (0.01--1 g kg(-1)) significantly inhibited passive cutaneous anaphylactic reaction activated by anti-DNP IgE to between 83.10 +/- 1.67% and 70.17 +/- 2.17%. SMWE (0.01--1 mg ml(-1)) also inhibited histamine release activated by compound 48/80 to between 93 +/- 2.65 and 70 +/- 1.50%. Moreover, SMWE (0.01--1 mg ml(-1)) had a significant inhibitory effect on IgE-induced tumor necrosis factor (TNF)-alpha secretion from rat peritoneal mast cells. These results indicate that SMWE inhibits immunologic and nonimmunologic stimulation-mediated anaphylactic reactions and TNF-alpha secretion from mast cells.

Administration, Oral↗

PubMed2001

Galectin-3 protects human breast carcinoma cells against nitric oxide-induced apoptosis: implication of galectin-3 function during metastasis.

Galectin-3 is a beta-galactoside-binding protein which regulates many biological processes including cell adhesion, migration, cell growth, tumor progression, metastasis, and apoptosis. Although the exact function of galectin-3 in cancer development is unclear, galectin-3 expression is associated with neoplastic progression and metastatic potential. Since studies have suggested that tumor cell survival in microcirculation determines the metastatic outcome, we examined the effect of galectin-3 overexpression in human breast carcinoma cell survival using the liver ischemia/reperfusion metastasis model. While the majority of control cells died by hepatic ischemia/reoxygenation, nearly all of galectin-3 overexpressing cells survived. We showed that galectin-3 inhibits nitrogen free radical-mediated apoptosis, one of the major death pathways induced during hepatic ischemia/reperfusion. Galectin-3 inhibition of apoptosis involved protection of mitochondrial integrity, inhibition of cytochrome c release and caspase activation. Taking these results together with the previous observation that galectin-3 inhibits apoptosis induced by loss of cell adhesion, we propose that galectin-3 is a critical determinant for anchorage-independent and free radical-resistant cell survival during metastasis.

Animals↗

PubMed2001

Characterization and immunological analysis of ferritin from the hemolymph of Galleria mellonella.

Ferritin, an iron-binding protein, was purified from the larval hemolymph of the wax moth, Galleria mellonella by KBr density ultracentrifugation and FPLC (Superose 6). The iron content of ferritin was determined by atomic emission spectroscopy and Ferene S stain. Native molecular mass of ferritin was estimated as 630 kDa. SDS-PAGE revealed that the ferritin consists of two major polypeptides of 26 and 32 kDa and one minor polypeptide of 30 kDa. An isoelectric point of ferritin was measured to be approximately 7.3 and only the 32-kDa subunit is glycosylated. The ferritin contains large amounts of lysine, glutamine, glutamic acid and leucine but tryptophan was not detected. Electron microscopic examination of negatively stained preparations showed an 11-nm particle in external diameter and 7-nm iron core. Ferritin is present in both the ovary and testis. Localization of ferritin by immunoelectron microscopy in ovary and testis revealed that the gold particles were located in vitelline membrane and yolk granules but not in follicular epithelium of ovary. In the testis, the gold particles were located in testicular fluid and lumen of vas deferens.

Amino Acids↗

PubMed2001

Sodium nitroprusside induces apoptosis of H9C2 cardiac muscle cells in a c-Jun N-terminal kinase-dependent manner.

Sodium nitroprusside (SNP) induces apoptosis in H9C2 cardiac muscle cells. Treatment with an exogenous NO donor SNP (2 mM) to H9C2 cells resulted in apoptotic morphological changes; a bright blue-fluorescent condensed nuclei and chromatin fragmentation by fluorescence microscope of Hoechst 33258-staining. The activity of caspase-3 like protease was increased during SNP-induced cell death. However, the activity of caspase-1 like protease was not affected by SNP. Pretreatment with Z-VAD-FMK (a pan-caspase inhibitor) or Ac-DEVD-CHO (a specific caspase-3 inhibitor) abrogated the SNP-induced cell death. SNP markedly activated three MAP kinases (JNK/SAPK, ERK and p38 MAP kinase) in the cardiac muscle cells. In this study, selective inhibition of the ERK or p38 MAPK pathway (by PD98059 or SB203580, respectively) had no effect on the extent of SNP-induced apoptosis in cardiac muscle cells. In contrast, inhibition of the JNK pathway by transfection of a dominant negative mutant of JNK markedly reduced the extent of SNP-induced cell death. Taken together, we suggest that JNK/SAPK will be related to SNP-induced apoptosis of H9C2 cardiac muscle cells.

Amino Acid Chloromethyl Ketones↗

PubMed2001

The p38 mitogen-activated protein kinase pathway regulates interleukin-6 synthesis in response to tumor necrosis factor in osteoblasts.

The induction of interleukin-6 (IL-6), using a proinflammatory cytokine (tumor necrosis factor-alpha), was studied in a human osteoblast cell line (MG-63) in relation to p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-kappaB transcription factor. When added to MG-63 cells, tumor necrosis factor-alpha (TNF-alpha) had a stimulatory effect on the production of IL-6, and this elevation was significantly reduced by SB203580, a specific p38 MAPK inhibitor. In addition, the stimulation of IL-6 release was also reduced by pyrrolidine dithiocarbamate (PDTC) or NF-kappaB SN50, which has been reported to be a potent NF-kappaB inhibitor. Both the NF-kappaB inhibitors in the presence of SB203580 had a more inhibitory effect on IL-6 release. In this study, TNF-alpha stimulated NF-kappaB binding affinity as well as p38 MAP kinase activation, leading to the release of IL-6. However, the specific inhibitor of p38 MAPK, SB203580, had no effect on TNF-alpha-induced NF-kappaB activation and both NF-kappaB inhibitors failed to reduce the p38 MAPK activation in the TNF-alpha-stimulated osteoblasts. In addition, inhibition of p38 MAPK partially, but significantly, impaired TNF-alpha-regulated release of osteocalcin, an important differentiation marker in osteoblasts. These results strongly suggest that both p38 MAPK and NF-kappaB are required in TNF-alpha-induced IL-6 synthesis and that these two TNF-alpha-activated pathways can be primarily dissociated. Furthermore, p38 MAPK may play a significant role in differentiation in MG-63 cells.

Antioxidants↗

PubMed2001

Bcl-2 induces cyclin D1 promoter activity in human breast epithelial cells independent of cell anchorage.

Cyclin D1 expression is co-regulated by growth factor and cell adhesion signaling. Cell adhesion to the extracellular matrix activates focal adhesion kinase (FAK), which is essential for cyclin D1 expression. Upon the loss of cell adhesion, cyclin D1 expression is downregulated, followed by apoptosis in normal epithelial cells. Since bcl-2 prevents apoptosis induced by the loss of cell adhesion, we hypothesized that bcl-2 induces survival signaling complementary to cell adhesion-mediated gene regulation. In the present study, we investigated the role of bcl-2 on FAK activity and cyclin D1 expression. We found that bcl-2 overexpression induces cyclin D1 expression in human breast epithelial cell line MCF10A independent of cell anchorage. Increased cyclin D1 expression in stable bcl-2 transfectants is not related to bcl-2-increased G1 duration, but results from cyclin D1 promoter activation. Transient transfection studies confirmed anchorage-independent bcl-2 induction of cyclin D1 promoter activity in human breast epithelial cell lines (MCF10A, BT549, and MCF-7). We provide evidence that bcl-2 induction of cyclin D1 expression involves constitutive activation of focal adhesion kinase, regardless of cell adhesion. The present study suggests a potential oncogenic activity for bcl-2 through cyclin D1 induction, and provides an insight into the distinct proliferation-independent pathway leading to increased cyclin D1 expression in breast cancer.

Breast↗

PubMed2001

The effects of thiol compounds and ebselen on nitric oxide activity in rat aortic vascular responses.

1. Thiols have been implicated to play a role in a variety of aspects of nitric oxide (NO) generation and activity. Thiol dependence of nitric oxide synthase (NOS) has remained controversial and its mechanism is not clear. This study investigates possible mechanisms between thiol (SH group) and NOS activation, through thiol compounds (glutathione, dithiothreitol, N-acetyl-L-cysteine) and Ebselen [2-phenyl-1,2-benzisoselenazole-3(2H)-one] on rat aortic vascular responses. 2. In rat thoracic aorta, acetylcholine (10(-6)-10(-9) M) induced a relaxation of phenylephrine (PE) (10(-7) M)-induced tone, which was inhibited dose dependently by increasing concentration of ebselen (1-10 microM). 3. In rings of rat thoracic aorta, ebselen and NOS inhibitors (NG-monomethyl-L-arginine, NG-nitro-L-arginine methyl ester) produced an augmentation of phenylephrine (10(-7) M)- induced tone and acetylcholine induced a relaxation of PE (10(-7) M)-induced tone in rat thoracic aorta, which was inhibited by ebselen (10 microM) like NOS inhibitor. 4. The thiol compounds (glutathione, dithiothreitol, and N-acetyl-L-cysteine) alone did not change vascular tone in rat thoracic aorta. Pretreatment with thiol compounds before ebselen treatment, however, reversed the inhibitory effect of ebselen which acts like the NOS inhibitor in rat thoracic aorta. Posttreatment with thiol compounds after ebselen treatment did not reverse the inhibitory effect of ebselen by as much as pretreatment. 5. Calcium ionophore A23187 (10(-7) M)-induced vasodilation was inhibited in ebselen pretreated rat thoracic aorta, but sodium nitroprusside (SNP, 10(-7) M)-induced relaxation was not inhibited by ebselen. This suggests that NOS is involved in the inhibitory effect of ebselen on rat thoracic aorta relaxation. 6. These results suggest that ebselen exerts an inhibitory action on the nitric oxide synthesis in rat thoracic aorta by interacting with thiol groups.

Acetylcholine↗

PubMed2001

Hypoxia induces apoptosis by caspase activation accompanying cytochrome C release from mitochondria in MC3T3E1 osteoblasts. p38 MAPK is related in hypoxia-induced apoptosis.

The aim of this study is to elucidate the possible mechanism of apoptosis in response to hypoxia in MC3T3E1 osteoblasts. MC3T3E1 osteoblasts under hypoxic conditions (2% oxygen) resulted in apoptosis in a time-dependent manner estimated by DNA fragmentation assay and nuclear morphologystained with fluorescent dye, Hoechst 33258. Pretreatment with Z-VAD-FMK, a pan-caspase inhibitor, or Z-DEVD-CHO, a specific caspase-3 inhibitor, completely suppressed the DNA ladder in response to hypoxia. An increase in caspase-3-like protease (DEVDase) activity was observed during apoptosis, but no caspase- activity (YVADase) was detected. To confirm what caspases are involved in apoptosis, western blot analysis was performed using anti-caspase-3 or -6 antibody. The 10-kDa protein, corresponding to the active products of caspase-3 and the 10-kDA protein of the active protein of caspase-6 were generated in hypoxia-challenged cells in which processing of the full length form of caspase-3 and -6 was evident. With a time course similar to this caspase-3 and -6 activation was evident, hypoxic stress caused the cleavage of lamin A, typical of caspase-6 activity. In addition, the stress elicited the release of cytochrome c into the cytosol during apoptosis. Furthermore, we have observed that pre-treatment with SB203580, a selective p38 MAP kinase (p38 MAPK) inhibitor, attenuated the hypoxia-induced apoptosis. The addition of SB203580 suppressed caspase-3 and -6-like protease activity by hypoxia up to 50%. In contrast, PD98059 had no effect on the hypoxia-induced apoptosis. To confirm the involvement of MAP kinase, JNK/SAPK, ERK, or p38 kinase assay was performed. Although p38 MAPK was activated in response to hypoxic treatment, the other MAP kinase -JNK/SAPK or ERK- was not or modestly activated. These results suggest that p38 MAPK positively regulates hypoxia-induced apoptosis in MC3T3E1 osteoblasts.

3T3 Cells↗

PubMed2001

Kunbi-Boshin-Hangam-Tang stimulates nitic oxide production through activation of nuclear factor-kappaB.

The objective of the currently study was to determine the effect of Kunbi-Boshin-Hangam-Tang (KBH-Tang) on the production of nitric oxide (NO). Stimulation of RAW 264.7 cells with KBH-Tang after the treatment of recombinant interferon-gamma (rIFN-gamma) resulted in increased NO synthesis. KBH-Tang partially increased NO synthesis by itself. When KBH-Tang was used in combination with rIFN-gamma, there was a marked cooperative induction of NO synthesis in a dose-dependent manner. This increase in NO synthesis was reflected as increased amount of inducible NO synthase (iNOS) protein. NO production was inhibited by NG-monomethyl-L-arginine (NGMMA). Furthermore, activation of nuclear factor (NF)-kappaB was increased by KBH-Tang. These results suggest that KBH-Tang may stimulate the NO production through the activation of the NF-kappaB.

Animals↗

PubMed2001

Signal transduction of nitric oxide donor-induced protection in hydrogen peroxide-mediated apoptosis in H9C2 cardiomyoblasts.

Nitric oxide (NO) attenuates hydrogen peroxide (H2O2)-mediated injury to H9C2 cardiomyoblasts. To examine the role of nitric oxide, cultured H9C2 cardiomyoblasts were treated with H2O2 for 2 h in the presence or absence of the NO donor, diethylamine nitric oxide (DEANO). DEANO (30 microM) attenuated H2O2-induced apoptosis in H9C2 cells. H2O2-exposed H9C2 cells resulted in apoptosis in a time-dependent manner estimated by DNA fragmentation assay, nuclear morphology stained with fluorescent dye, Hoechst 33258 and Annexin V staining. Pretreatment with z-VAD-FMK, a pancaspase inhibitor, or z-DEVD-CHO, a specific caspase-3 inhibitor, completely suppressed the DNA ladder in response to H2O2. An increase in caspase-3-like protease (DEVDase) activity was observed during apoptosis, but no caspase-1 activity (YVADase) was detected. Treatment of H9C2 cells with 100 microM H2O2, resulted in a strong activation of JNK/SAPK. However, the activation of JNK/ SAPK was clearly attenuated by 30 microM DEANO. Furthermore, the dominant negative JNK and SEK1-expressing cells displayed a marked decrease in a number of apoptotic cells. This inhibition of JNK1 in the system is involved in the protection of H2O2-induced apoptosis in H9C2 cardiomyoblasts.

Animals↗

PubMed2001

Nitric oxide prevents the IFN-gamma/LPS-induced hepatotoxicity in a protein kinase G-independent manner.

Although it has been well known that the role of LPS on hepatotoxicity is mediated through TNF-alpha, the direct cytotoxic effect of LPS on IFN-gamma-primed hepatocytes has not yet been clearly demonstrated. Here, we demonstrate that the IFN-gamma-mediated death of murine embryonic liver BNL CL2 cells is potentiated by LPS (0.5 microg/ml). In addition, an exogenous NO donor, sodium nitroprusside (SNP) significantly prevents cell death induced by IFN-gamma alone or IFN-gamma plus LPS (IFN-gamma/LPS) in a dose-dependent manner over 25 microM. SNP significantly blocked the death of BNL CL2 cells only when it was added within 12 hr after treatment of IFN-gamma and IFN-gamma/LPS. The preventive effect of SNP occurred in parallel with the suppression of caspase 3-like protease activation. We have also demonstrated that a relatively high concentration as well as an appropriate period of exposure to NO may be critical to maintain cell viability from the cytotoxic effect of IFN-gamma and IFN-gamma/LPS. Furthermore, the preventive effect of SNP on IFN-gamma/LPS-induced cell death is mediated by a protein kinase G (PKG)-independent manner.

Animals↗

PubMed2001

Estrogen regulates cytokine release in human mast cells.

Estrogens are important for bone homeostasis and are classified as anti-resorptive agents. In ovariectomized rats, mast cell changes occurred during the activation of resorption. In addition, quantitative changes occurred in mast cell population residing near the site undergoing resorption. Considering these studies, mast cells may play a role in osteoporosis. Therefore, it is of paramount importance to study mast cell cytokine production also in the presence or absence of estrogen. When cultured in the absence of estrogen, human mast cells treated with PMA or A23187 demonstrated significantly greater release of TNF-alpha and IL-6 than cells grown under estrogen-depleted condition. Our results show that treatment of mast cells with estrogen prevented PMA or A23187-stimulated TNF-alpha or IL-6 release. These data provide evidence for a potent inhibition of cytokines by estrogen in human mast cells. This study may help to explain the association between mast cells and osteoporosis.

Calcimycin↗