• Journal of Life Science
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• v.8 no.4
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• pp.410-415
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• 1998

Procine pepsin hydrolysis of hexapeptide L-S-pNF-Nle-A-OMe in the presence of dipeptide L-L generates a new peak on HPLC analysis of reaction mixtures that is not seen when enzyme is incubated with either peptide alone. The peaks can be detected spectroscopically at either 214 or 254 nm, the latter consistent with a new peptide containing the p-nitro-F residue. The data suggest acyl transpeptidation between E(L-S-pNF) and L-L to form L-S-pNF-L-L. Consistent with this inference are (1) the ability of L-L-NH$_{2}$ and inability of Boc-L-L to undergo a similar transpeptidation reaction, and (2) the data from electrospray mass spectrum. This synthesis requires that Nle-A-L-OMe be released before L-S-pNF, an order opposite to that proposed on the basis of product inhibition kinetics. Consistent with this inference are reciprocal solvent isotope effects ; normal isotope effects of 1.736$\pm$0.121 on the formation of Nle-A-L-OMe and 2.281$\pm$0.184 in the formation of L-S-pNF, coupled to an inverse isotope effects of 0.576$\pm$0.045 on the formation of L-S-pNF-L-L. Because transpeptidation precedes faster in D$_{2}$O, the isotopically-sensitive step must occur after release of Nle-A-L-OMe. Isotopically-enhanced transpeptidation is consistent with the Uni-Bi iso memchanism postulated on the basis of an isotope effects on Vmax but not on Vmax/Km$^{1)}$ and confirmed by isotope effects on the onset of inhibition by pepstatin$^{2)}$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2125-2132
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• 2012

Fluoxetine and tianeptine are commonly used as antidepressants (AD), and haloperidol and risperidone are widely used as antipsychotic drugs (APD), and it modulates various ion channels. TREK2 channel subfamily is very similar to physiological properties of TREK1 channel which can play important roles in the pathophysiology of mental disorders such as depression and schizophrenia, therefore, the pharmacological effect of psychiatric and depression drug on TREK2 channel may be similar to those of TREK1. Using the excised inside-out patch-clamp technique, we have examined the effects of APD and AD on cloned TREK2 channel expressed CHO cells. Fluoxetine (selective serotonin release inhibitor, SSRI) inhibited the TREK2 channel in a concentration-dependent manner ($IC_{50}$ $13{\mu}M$), whereas selective serotonin reuptake enhancer (SSRE) tianeptine increased without reducing the TREK2 channel activity. Haloperidol also inhibited the TREK2 channel in a concentration-dependent manner ($IC_{50}$ $44{\mu}M$), whereas even higher concentration ($100{\mu}M$) of risperidone did not completely inhibit on the activity. This study showed that TREK2 channel was preferentially blocked by fluoxetine rather than tianeptine, and inhibited by haloperidol rather than risperidone, suggesting differential effect of TREK2 channels by APD and AD may contribute to some mechanism of adverse side effects.

• Journal of Life Science
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• v.21 no.11
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• pp.1549-1557
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• 2011

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively induce apoptosis in many types of transformed cells; however, some human hepatocellular carcinoma cells are particularly resistant to the effects of TRAIL. Although genistein, a natural isoflavonoid phytoestrogen, has been shown to have pro-apoptotic activity against human cancer cell lines, little is known about the mechanism of genistein in terms of TRAIL-induced apoptosis. In the present study, it was investigated whether or not combined treatment with genistein and TRAIL synergistically induced apoptosis in Hep3B hepatocarcinoma cells. Results indicate that treatment with TRAIL in combination with nontoxic concentrations of genistein sensitized TRAIL-resistant Hep3B cells to TRAIL-induced apoptosis, which was associated with mitochondrial dysfunction. Further, the inhibition of p38 mitogen-activated protein kinase (MAPK) activation markedly decreased genistein and TRAIL-induced cell viability and apoptosis by enhanced truncation of Bid, increase of pro-apoptotic Bax, decrease of anti-apoptotic Bcl-2, and release of cytochrome c from mitochondria to cytoplasm. Activation of caspases and degradation of poly (ADP-ribose) polymerase induced by the combined treatment was also markedly increased by the inhibition of p38 MAPK, through the mitochondrial amplification step. In conclusion, our data suggest that genistein sensitizes TRAIL-induced-apoptosis via p38 MAPK-dependent pathway.

• Journal of Life Science
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• v.24 no.7
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• pp.798-803
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• 2014

Cathepsin D (CtsD), an aspartyl peptidase, is involved in apoptosis, resulting in the release of cytochrome C from mitochondria in cells. Here, we investigated microRNA regulation of CtsD expression in 3T3-L1 cells First, we observed the expression of CtsD in cells in response to doxorubicin (Dox). As expected, the level of CtsD mRNA was increased in 3T3-L1 cells exposed to Dox in a dose-dependent manner. Cellular viability of ectopically expressed CtsD cells was also decreased. Next, we used the miRanda program to search for particular microRNA targeting CtsD. MiR-145 was selected as a putative controller for CtsD because miR-145 had a high mirSVR score. In a reporter assay, the luciferase activity of cells containing the CtsD 3'-UTR region was decreased in cells transfected with miR-145 mimic compared to that of a control. The level of CtsD expression was down-regulated in preadipocytes ectopically expressing miR-145 and up-regulated by an miR-145 inhibitor. Cells also suppressed miR-145 expression when exposed to Dox. The miR-145 inhibitor reduced the cellular viability of 3T3-L1 cells. Taken together, these data suggest that miR-145 regulates CtsD-mediated cell death in adipocytes. These findings may have valuable implications concerning the molecular mechanism of CtsD-mediated cell death in obesity, suggesting that CtaD could be a useful therapeutic tool for the prevention and treatment of obesity by regulating fat cell numbers.

• Journal of Life Science
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• v.24 no.7
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• pp.777-783
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• 2014

Cathepsin D (CtsD), an aspartyl peptidase, is involved in apoptosis, resulting in the release of cytochrome C from mitochondria in cells. Here, we investigated microRNA regulation of CtsD expression in 3T3-L1 cells. First, we observed the expression of CtsD in cells in response to doxorubicin (Dox). As expected, the level of CtsD mRNA increased in 3T3-L1 cells exposed to Dox in a dose-dependent manner. The cellular viability of ectopically expressed CtsD cells was decreased. Next, we used the miRanda program to search for particular microRNA targeting CtsD. MiR-145 was selected as a putative controller of CtsD because it had a high mirSVR score. In a reporter assay, the luciferase activity of cells containing the CtsD 3'-UTR region decreased in cells transfected with a miR-145 mimic compared to that of a control. The level of CtsD expression was down-regulated in preadipocytes ectopically expressing miR-145 and up-regulated by an miR-145 inhibitor. Cells also suppressed miR-145 expression when exposed to Dox. The miR-145 inhibitor reduced the cellular viability of 3T3-L1 cells. Taken together, these data suggest that miR-145 regulates CtsD-mediated cell death in adipocytes. These findings may have valuable implications concerning the molecular mechanism of CtsD-mediated cell death in obesity, suggesting that CtsD could be a useful therapeutic tool for the prevention and treatment of obesity by regulating fat cell numbers.

• Journal of Life Science
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• v.23 no.1
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• pp.137-142
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• 2013

Human adipose-derived mesenchymal stem cells (hMSCs) are highly useful for vascular regeneration of injured or inflamed tissue. Lipopolysaccharide (LPS) is a potent activator of macrophages and stimulates macrophages to release inflammatory cytokines. In the present study, we explored the role of LPS-activated macrophages in the differentiation of hMSCs to smooth muscle cells (SMCs). We demonstrated that conditioned medium from LPS-induced macrophages (LPS CM) stimulates differentiation of hMSCs to SMCs, as evidenced by increased expression of smooth muscle-specific markers, including alpha-smooth muscle actin (${\alpha}$-SMA), smooth muscle-myosin heavy chain, and calponin. LPS induced the secretion of $PGF2{\alpha}$ from macrophages, and $PGF2{\alpha}$ treatment stimulated expression levels of SMC-specific markers in hMSCs. Furthermore, small interfering RNA-mediated silencing of the $PGF2{\alpha}$ receptor inhibited LPS CM-stimulated ${\alpha}$-SMA expression. These results suggest that LPS-activated macrophages promote differentiation of hMSCs to SMCs through a $PGF2{\alpha}$-dependent mechanism.

• Journal of Life Science
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• v.27 no.5
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• pp.545-552
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• 2017

Julbernardia globiflora, a tropical African tree widespread in Miombo woodland, has been used in folk medicine for the treatment of depression and stomach problems. However, the antioxidative and anticancer activities of J. globiflora remain unclear. The objective of this study is to evaluate the antioxidative and anticancer effects of methanol extract of J. globiflora (MEJG) and the molecular mechanism of its anticancer activity in human colon carcinoma HT29 cells. MEJG exhibited significant antioxidative effect with an $IC_{50}$ (concentration at 50% inhibition) value of $1.23{\mu}g/ml$ measuring by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and inhibited cell proliferation in a dose-dependent manner in HT29 cells. We found that MEJG induced apoptosis of HT29 cells with the increase of apoptotic cells and apoptotic bodies using Annexin V staining and 4,6-diamidino-2-phenylindole (DAPI) staining, respectively. The MEJG treatment showed the increase of Fas, a death receptor, and Bax, a pro-apoptotic protein, and the decrease of Bcl-2, an anti-apoptotic protein, resulting in the release of cytochrome c from the mitochondria into the cytosol and activation of caspase-3, -8 and -9. The apoptotic effects of MEJG were confirmed by cleavage of poly (ADP-ribose) polymerase (PARP). Collectively, these results suggest that MEJG may exert the anticancer effect in HT29 cells by inducing apoptosis via both the intrinsic and extrinsic pathways.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.2
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• pp.103-114
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• 2017

Gnaphalium affine D. DON (GA) has been used as a vegetable as well as a folk medicine in East Asia. The antioxidant and anti-complementary activity of GA extract (GAE) has also been reported. However, little is known about its anti-inflammatory and anti-allergic effect and mechanism of action. In this study, we evaluated the inhibitory effects of GAE on the production of inflammatory mediators such as NO, $PGE_2$, TLR4, eotaxin-1 and histamine. Our results suggest that GAE inhibits the production of NO and $PGE_2$ by inhibiting transcriptional activation via the involvement of iNOS and COX-2. The LPS-induced expression of Toll-like receptor 4 (TLR4) was also attenuated. In addition, GAE inhibited A23187-induced histamine release from MC/9 mast cells. It also inhibited the production of eotaxin-1 induced by IL-4. Collectively, these results suggest that GAE may have considerable potential as a cosmetic ingredient with anti-inflammatory and anti-allergic properties.

• Journal of Sasang Constitutional Medicine
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• v.15 no.1
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• pp.72-89
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• 2003

To elucidate the neuroprotective effect of Yeoldahanso-tang(YHT) on nerve cells damaged by hypoxia, the cytotoxic effects of exposure to hypoxia were determined by XTT(SODIUM3,3'-{I-[(PHENYLAMINO) CARBONYL]-3,4-TETRAZOLIUM}- BIS (4-METHOXY-6-NITRO) BENZENE SULFONIC ACID HYDRATE), NR(Neutral red), MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and SRB(Sulforhodamin B) asssay. The activity of catalase and SOD(Superoxide dismutase) was measured by spectrophometry, and $TNF-{\alpha}$(Tumor cell necrosis $fector-{\alpha}$) and PKC(Protein kinase C) activity was measured after exposure to hypoxia and treatment of YHTWE. Also the neuroprotective effect of YHTWE was researched for the elucidatioion of neuroprotective mechanism. The results were as follows; 1. Hypoxia decreased cell viability measured by XTT, NR assay when cultured cerebral neurons were exposed to 95% N2/5% CO2 for $2{\sim}26$ minutes in these cultures and YHTWE inhibited the decrease of cell viability. 2. H2O2 treatment decreased cell viability measured by MTT, and SRB assay when cultured cerebral neurons were exposed to 1-80 ${\mu}M$ for 6 hours, but YHTWE inhibited the decrease of cell viability. 3. Hypoxia decreased catalase and SOD activity, and also $TNF-{\alpha}$ and PKC activity in these cultured cerebral neurons, but YHTWE inhibited the decrease of the catalase and SOD activity in these cultures. 4. Hypoxia triggered the apoptosis via caspase activation and internucleosomal DNA fragmentation. Also hypoxia stimulate the release of cytochrome c forom mitochondria. YHTWE inhibited the apoptosis via caspase activation induced by hypoxia. From these results, it can be suggested that brain ischemia model induced hypoxia showed neurotoxicity on cultured mouse cerebral neurons, and the YHTWE has the neuroprotective effect in blocking the neurotoxicity induced by hypoxia in cultured mouse cerebral neurons.

• Journal of Life Science
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• v.19 no.8
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• pp.1047-1054
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• 2009

Oral squamous carcinoma (OSC) cells present resistance to chemotherapeutic agents-mediated apoptosis in the late stages of malignancy. Advances in the understanding of bacterial toxins have produced new strategies for the treatment of cancers. It was demonstrated here that Pseudomonas aeruginosa exotoxin A (PEA) significantly decreased the viability of chemoresistant YD-9 cells in the apoptosis mechanism. Apoptotic manifestations were evident through changes in nuclear morphology and generation of DNA fragmentation. PEA treatment induced caspase-3, -6 and -9 cleavage, and activation. These events preceded proteolysis of the caspase substrates poly (ADP-ribose) polymerase (PARP), DNA fragmentation factor 45 (DFF45), and lamin A in YD-9 cells. The reduction of mitochondrial membrane potential, release of cytochrome c and SmacjDlABLO from mitochondria to cytosol, andtranslocation of AlF into nucleus were shown. While p53, p21 and $14-3-3{\gamma}$ were upregulated, cyclin Band cdc2 were downregulated by PEA treatment. Taken together, PEA induces apoptosis in chemoresistant YD-9 cells via activation of caspases, mitochondrial events and regulation of cell cycle genes.