• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1607-1615
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• 2007

We investigated the applicability of the TEM-l ${\beta}$-lactamase fragment complementation (BFC) system to develop a strategy for the screening of protein-protein interactions in bacteria. A BFC system containing a human Fas-associated death domain (hFADD) and human Fas death domain (hFasDD) was generated. The hFADD-hFasDD interaction was verified by cell survivability in ampicillin-containing medium and the colorimetric change of nitrocefin. It was also confirmed by His pull-down assay using cell lysates obtained in selection steps. A coiled-coil helix coiled-coil domain-containing protein 5 (CHCH5) was identified as an interacting protein of human uracil DNA glycosylase (hUNG) from the bacterial BFC cDNA library strategy. The interaction between hUNG and CHCH5 was further confirmed with immunoprecipitation using a mammalian expression system. CHCH5 enhanced the DNA glycosylase activity of hUNG to remove uracil from DNA duplexes containing a U/G mismatch pair. These results suggest that the bacterial BFC cDNA library strategy can be effectively used to identify interacting protein pairs.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.334-342
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• 2015

4-O-Methylhonokiol (MH), a bioactive compound derived from Magnolia officinalis, is known to exhibit antitumor effects in various cancer cells. However, the precise mechanism of its anticancer activity in cervical cancer cells has not yet been studied. In this study, we demonstrated that MH induces apoptosis in SiHa cervical cancer cells by enhancing peroxisome proliferator-activated receptor-gamma (PPARγ) activation, followed by inhibition of the PI3K/Akt pathway and intrinsic pathway induction. MH upregulated PPARγ and PTEN expression levels while it decreased p-Akt in the MH-induced apoptotic process, thereby supporting the fact that MH is a PPARγ activator. Additionally, MH decreased the expression of Bcl-2 and Bcl-XL, inducing the intrinsic pathway in MH-treated SiHa cells. Furthermore, MH treatment led to the activation of caspase-3/caspase-9 and proteolytic cleavage of polyADP ribose polymerase. The expression levels of Fas (CD95) and E6/E7 oncogenes were not altered by MH treatment. Taken together, MH activates PPARγ/PTEN expression and induces apoptosis via suppression of the PI3K/Akt pathway and mitochondria-dependent pathways in SiHa cells. These findings suggest that MH has potential for development as a therapeutic agent for human cervical cancer.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.2
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• pp.113-118
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• 2012

Ginsenosides are low molecular weight glycosides found in ginseng that exhibit neuroprotective effects through inhibition of $N$-methyl-D-aspartic acid (NMDA) receptor channel activity. Ginsenosides, like other natural compounds, are metabolized by gastric juices and intestinal microorganisms to produce ginsenoside metabolites. However, little is known about how ginsenoside metabolites regulate NMDA receptor channel activity. In the present study, we investigated the effects of ginsenoside metabolites, such as compound K (CK), protopanaxadiol (PPD), and protopanaxatriol (PPT), on oocytes that heterologously express the rat NMDA receptor. NMDA receptor-mediated ion current ($I_{NMDA}$) was measured using the 2-electrode voltage clamp technique. In oocytes injected with cRNAs encoding NMDA receptor subunits, PPT, but not CK or PPD, reversibly inhibited $I_{NMDA}$ in a concentration-dependent manner. The $IC_{50}$ for PPT on $I_{NMDA}$ was $48.1{\pm}4.6\;{\mu}M$, was non-competitive with NMDA, and was independent of the membrane holding potential. These results demonstrate the possibility that PPT interacts with the NMDA receptor, although not at the NMDA binding site, and that the inhibitory effects of PPT on $I_{NMDA}$ could be related to ginseng-mediated neuroprotection.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2717-2721
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• 2011

Peroxisome proliferator-activated receptors (PPARs) are a subfamily of nuclear receptors (NRs). Human peroxisome proliferator-activated receptor gamma (hPPAR${\gamma}$) has been implicated in the pathology of numerous diseases, including obesity, diabetes, and cancer. ELISA-based hPPAR${\gamma}$ activation assay showed that biapigenin increased the binding between hPPAR${\gamma}$ and steroid receptor coactivator-1 (SRC-1) by approximately 3-fold. In order to confirm that biapigenin binds to hPPAR${\gamma}$, fluorescence quenching experiment was performed. The results showed that biapigenin has higher binding affinity to hPPAR${\gamma}$ at nanomolar concentrations compared to indomethacin. Biapigenin showed anticancer activity against HeLa cells. Biapigenin was noncytotoxic against HaCa T cell. All these data implied that biapigenin may be a potent agonist of hPPAR${\gamma}$ with anticancer activity. We will further investigate its anticancer effects against human cervical cancer.

• BMB Reports
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• v.46 no.12
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• pp.594-599
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• 2013

The anti-inflammatory activity of eriodictyol and its mode of action were investigated. Eriodictyol suppressed tumor necrosis factor (mTNF)-${\alpha}$, inducible nitric oxide synthase (miNOS), interleukin (mIL)-6, macrophage inflammatory protein (mMIP)-1, and mMIP-2 cytokine release in LPS-stimulated macrophages. We found that the anti-inflammatory cascade of eriodictyol is mediated through the Toll-like Receptor (TLR)4/CD14, p38 mitogen-activated protein kinases (MAPK), extracellular-signal-regulated kinase (ERK), Jun-N terminal kinase (JNK), and cyclooxygenase (COX)-2 pathway. Fluorescence quenching and saturation-transfer difference (STD) NMR experiments showed that eriodictyol exhibits good binding affinity to JNK, $8.79{\times}10^5M^{-1}$. Based on a docking study, we propose a model of eriodictyol and JNK binding, in which eriodictyol forms 3 hydrogen bonds with the side chains of Lys55, Met111, and Asp169 in JNK, and in which the hydroxyl groups of the B ring play key roles in binding interactions with JNK. Therefore, eriodictyol may be a potent anti-inflammatory inhibitor of JNK.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2219-2223
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• 2012

Human peroxisome proliferator-activated receptor gamma ($hPPAR{\gamma}$) has been implicated in numerous pathologies, including obesity, diabetes, and cancer. Previously, we verified that amentoflavone is an activator of $hPPAR{\gamma}$ and probed the molecular basis of its action. In this study, we investigated the mechanism of action of amentoflavone in cancer cells and demonstrated that amentoflavone showed strong cytotoxicity against MCF-7 and HeLa cancer cell lines. We showed that $hPPAR{\gamma}$ expression in MCF-7 and HeLa cells is specifically stimulated by amentoflavone, and suggested that amentoflavone-induced cytotoxic activities are mediated by activation of $hPPAR{\gamma}$ in these two cancer cell lines. Moreover, amentoflavone increased PTEN levels in these two cancer cell lines, indicating that the cytotoxic activities of amentoflavone are mediated by increasing of PTEN expression levels due to $hPPAR{\gamma}$ activation.

• Journal of Ginseng Research
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• v.46 no.3
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• pp.408-417
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• 2022

Background: Korean Red Ginseng extract (KRGE) has been used as a health supplement and herbal medicine. Astrocytes are one of the key cells in the central nervous system (CNS) and have bioenergetic potential as they stimulate mitochondrial biogenesis. They play a critical role in connecting the brain vasculature and nerves in the CNS. Methods: Brain samples from KRGE-administered mice were tested using immunohistochemistry. Treatment of human brain astrocytes with KRGE was subjected to assays such as proliferation, cytotoxicity, Mitotracker, ATP production, and O₂ consumption rate as well as western blotting to demonstrate the expression of proteins related to mitochondria functions. The expression of hypoxia-inducible factor-1α (HIF-1α) was diminished utilizing siRNA transfection. Results: Brain samples from KRGE-administered mice harbored an increased number of GFAP-expressing astrocytes. KRGE triggered the proliferation of astrocytes in vitro. Enhanced mitochondrial biogenesis induced by KRGE was detected using Mitotracker staining, ATP production, and O₂ consumption rate assays. The expression of proteins related to mitochondrial electron transport was increased in KRGE-treated astrocytes. These effects were blocked by HIF-1α knockdown. The factors secreted from KRGE-treated astrocytes were determined, revealing the expression of various cytokines and growth factors, especially those related to angiogenesis and neurogenesis. KRGE-treated astrocyte conditioned media enhanced the differentiation of adult neural stem cells into mature neurons, increasing the migration of endothelial cells, and these effects were reduced in the background of HIF-1α knockdown. Conclusion: Our findings suggest that KRGE exhibits prophylactic potential by stimulating astrocyte mitochondrial biogenesis through HIF-1α, resulting in improved neurovascular function.

• BMB Reports
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• v.53 no.7
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• pp.349-356
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• 2020

Mass spectrometry (MS) is an ideal tool for analyzing multiple types of (bio)molecular information simultaneously in complex biological systems. In addition, MS provides structural information on targets, and can easily discriminate between true analytes and background. Therefore, imaging mass spectrometry (IMS) enables not only visualization of tissues to give positional information on targets but also allows for molecular analysis of targets by affording the molecular weights. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS is particularly effective and is generally used for IMS. However, the requirement for an organic matrix raises several limitations that get in the way of accurate and reliable images and hampers imaging of small molecules such as drugs and their metabolites. To overcome these problems, various organic matrix-free LDI IMS systems have been developed, mostly utilizing nanostructured surfaces and inorganic nanoparticles as an alternative to the organic matrix. This minireview highlights and focuses on the progress in organic matrix-free LDI IMS and briefly discusses the use of other IMS techniques such as desorption electrospray ionization, laser ablation electrospray ionization, and secondary ion mass spectrometry.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.496-496
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• 2003

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.477-477
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• 2003