• Journal of Microbiology and Biotechnology
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• v.25 no.8
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• pp.1390-1400
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• 2015

Quorum sensing is a process of cell-to-cell communication in which bacteria produce autoinducers as signaling molecules to sense cell density and coordinate gene expression. In the present study, a LuxI-type synthase, AnoI, and a LuxR-type regulator, AnoR, were identified in Acinetobacter nosocomialis, an important nosocomial pathogen, by sequence analysis of the bacterial genome. We found that N-(3-hydroxy-dodecanoyl)- _L -homoserine lactone (OH-dDHL) is a quorum-sensing signal in A. nosocomialis. The anoI gene deletion was responsible for the impairment in the production of OH-dDHL. The expression of anoI was almost abolished in the anoR mutant. These results indicate that AnoI is essential for the production of OH-dDHL in A. nosocomialis, and its expression is positively regulated by AnoR. Moreover, the anoR mutant exhibited deficiency in biofilm formation. In particular, motility of the anoR mutant was consistently and significantly abolished compared with that of the wild type. The deficiency in the biofilm formation and motility of the anoR mutant was significantly restored by a functional anoR, indicating that AnoR plays important roles in the biofilm formation and motility. Furthermore, the present study showed that virstatin exerts its effects on the reduction of biofilm formation and motility by inhibiting the expression of anoR. Consequently, the combined results suggest that AnoIR is a quorum-sensing system that plays important roles in the biofilm formation and motility of A. nosocomialis, and virstatin is an inhibitor of the expression of anoR.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.3
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• pp.331-341
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• 2018

The aim of the present study was to examine the effects of preemptive analgesia on the development of trigeminal neuropathic pain. For this purpose, mechanical allodynia was evaluated in male Sprague-Dawley rats using chronic constriction injury of the infraorbital nerve (CCI-ION) and perineural application of 2% QX-314 to the infraorbital nerve. CCI-ION produced severe mechanical allodynia, which was maintained until postoperative day (POD) 30. An immediate single application of 2% QX-314 to the infraorbital nerve following CCI-ION significantly reduced neuropathic mechanical allodynia. Immediate double application of QX-314 produced a greater attenuation of mechanical allodynia than a single application of QX-314. Immediate double application of 2% QX-314 reduced the CCI-ION-induced upregulation of GFAP and p-p38 expression in the trigeminal ganglion. The upregulated p-p38 expression was co-localized with NeuN, a neuronal cell marker. We also investigated the role of voltage-gated sodium channels (Navs) in the antinociception produced by preemptive application of QX-314 through analysis of the changes in Nav expression in the trigeminal ganglion following CCI-ION. Preemptive application of QX-314 significantly reduced the upregulation of Nav1.3, 1.7, and 1.9 produced by CCI-ION. These results suggest that long-lasting blockade of the transmission of pain signaling inhibits the development of neuropathic pain through the regulation of Nav isoform expression in the trigeminal ganglion. Importantly, these results provide a potential preemptive therapeutic strategy for the treatment of neuropathic pain after nerve injury.

• Journal of Microbiology
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• v.41 no.1
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• pp.46-51
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• 2003

RAD6 in yeast mediates postreplication DNA repair and is responsible for DNA-damage induced mutations. RAD6 encodes ubiquitin-conjugating enzyme that is well conserved among eukaryotic organisms. However, the molecular targets and consequences of their ubiquitination by Rad6 have remained elusive. In Aspergillus nidulans, a RAD6 homolog has been isolated and shown to be an allele of uvs). We screened a CDNA library to isolate UVSJ-interacting proteins by the yeast two-hybrid system. JIPA was identified as an interactor of UVSJ. Their interaction was confirmed in vitro by a GST-pull down assay. JIPA was also able to interact with mutant UVSJ proteins, UVSJl and the active site cysteine mutant UVSJ-C88A. The N- and the C-terminal regions of UVSJ required for the interaction with UVSH, a RAD18 homolog of yeast which physically interacts with Rad6, were not necessary for the JIPA and UVSJ interactions. About 1.4 kb jipA transcript was detected in Northern analysis and its amount was not significantly increased in response to DNA-damaging agents. A genomic DNA clone of the jipA gene was isolated from a chromosome I specific genomic library by PCR-sib selection. Sequence determination of genomic and cDNA of jipA revealed an ORF of 893 bp interrupted by 2 introns, encoding a putative polypeptide of 262 amino acids. JIPA has 33% amino acid sequence identity to TIP41 of Saccharomyces cerevisiae which negatively regulates the TOR signaling pathway.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1166-1173
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• 2006

The aqueous extracts of Cortex Caryophylli (AEC) induced dose-dependent relaxation of phenylephrine-precontracted aorta, which was abolished by removal of functional endothelium. Pretreatment of the endothelium-intact aortic tissues with N$^G$_nitro-L-arginine methyl ester (L-NAME) or 1 H-[1,2,4]-oxadiazole-[4,3-${\alpha}$l-quinoxalin-1-one (ODQ) inhibited the relaxation induced by AEC. AEC-induced vascular relaxations were also markedly attenuated by addition of verapamil, diltiazem and glibenclamide, tetraethylammonium (TEA), respectively, while the relaxation effect of AEC was not blocked by indomethacin, atropine, or propranolol. Moreover, incubation of endothelium-intact aortic rings with AEC increased the production of cGMP. These results suggest that AEC dilates vascular smooth muscle via endothelium-dependent nitric oxide/cGMP signaling, which seems to be causally related with L-type Ca$^{2+}$ and K$^+$ channels.

• Biomolecules & Therapeutics
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• v.25 no.3
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• pp.272-278
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• 2017

Fucoidan has been reported to exhibit various beneficial activities ranging from to antivirus and anticancer properties. However, little information is available about the effects of fucoidan on cerebral ischemia-reperfusion injury (IRI). Our study aimed to explore the effects of fucoidan on cerebral IRI, as well as the underlying mechanisms. Sprague-Dawley (SD) rats were randomly subjected to four groups: Sham, IRI+saline (IRI+S), IRI+80 mg/kg fucoidan (IRI+F80), and IRI+160 mg/kg fucoidan (IRI+F160). Fucoidan (80 mg/kg or 160 mg/kg) was intraperitoneally injected from 7 days before the rats were induced to cerebral IRI model with middle cerebral artery occlusion (MCAO) method. At 24 h after reperfusion, neurological deficits and the total infarct volume were determined. The levels of inflammation-associated cytokines (interleukin (IL)-$1{\beta}$, IL-6, myeloperoxidase (MPO), and tumor necrosis factor (TNF)-${\alpha}$), oxidative stress-related proteins (malondialdehyde (MDA) and superoxide dismutase (SOD)) in the ischemic brain were measured by enzyme-linked immunosorbent assay (ELISA). Besides, the levels of apoptosis-related proteins (p-53, Bax, and B-cell lymphoma (Bcl)-2) and mitogen-activated protein kinase (MAPK) pathway (phosphorylation-extracellular signal-regulated kinase (p-ERK), p-c-Jun N-terminal kinase (JNK), and p-p38) were measured. Results showed that administration of fucoidan significantly reduced the neurological deficits and infarct volume compared to the IRI+S group in a dose-dependent manner. Also, fucoidan statistically decreased the levels of inflammation-associated cytokines, and oxidative stress-related proteins, inhibited apoptosis, and suppressed the MAPK pathway. So, Fucoidan plays a protective role in cerebral IRI might be by inhibition of MAPK pathway.

• Journal of Photoscience
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• v.12 no.1
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• pp.1-9
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• 2005

The ubiquitin E3 ligase COP1 (Constitutive Photomorphogenesis 1) is a protein repressor of photomorphogenesis in Arabidopsisplants, and it found in various organisms, including animals. The COP1 protein regulates the stability of many of the light-signaling components that are involved in photomorphogenesis and in the developmental processes. To study the effect of COP1 on flowering in a short day plant, we have cloned a full-length of PnCOP1 (Pharbitis nil COP1) cDNA from Pharbitis nil Choisy cv. Violet, and we examined its transcript levels under various conditions. A full-length PnCOP1 cDNA consists of 2,280 bp nucleotidesthat contain 47 bp of 5'-UTR, 232 bp of 3'-UTR including the poly (A) tail, and 1,998 bp of the coding sequence. The deduced amino acid sequence contains 666 amino acids, giving it a theoretical molecular weight of 75 kD and a isolectric point of 6.2. The PnCOP1 contains three distinct domains, an N-terminal $Zn^2+$-binding RING-finger domain, a coiled-coil structure, and WD40 repeats at the C-terminal, implying that the protein plays a role in protein-protein interactions. The PnCOP1 transcript was detected in the cotyledon, hypocotyls and leaves, but not in root. The levels of the PnCOP1 transcript were reduced in leaves that were a farther distance away from the cotyledons. The expression level of the PnCOP1 gene was inhibited by light, while the expression was increased in the dark. During the floral inductive 16 hour-dark period for Pharbitis nil, the expression was increased and it reached its maximum at the 12th hour of the dark period. The levels of PnCOP1 mRNA were dramatically reduced upon light illumination. These results suggest that PnCOP1 may play an important function in the floral induction of Pharbitis nil.

• Molecules and Cells
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• v.21 no.1
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• pp.121-128
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• 2006

Maitotoxin (MTX) is known as one of the most potent marine toxins involved in Ciguatera poisoning, but intracellular signaling pathways caused by MTX was not fully understood. Thus, we have investigated whether intracellular reactive oxygen species (ROS) are involved in MTX-induced cellular responses in human umbilical vein endothelial cells. MTX induced a dose-dependent increase of intracellular [$Ca^{2+}$]. MTX stimulated the production of intracellular ROS in a dose- and time-dependent manner, which was suppressed by BAPTA-AM, an intracellular $Ca^{2+}$ chelator. Ionomycin also elevated the ROS production in a dose-dependent manner. MTX elevated transamidation activity in a time-dependent manner and the activation was largely inhibited by transfection of tissue transglutaminase siRNA. The activation of tissue transglutaminase and ERK1/2 by MTX was suppressed by BAPTA-AM or ROS scavengers. In addition, MTX-induced cell death was significantly delayed by BAPTA-AM or a ROS scavenger. These results suggest that [$Ca^{2+}$]-dependent generation of intracellular ROS, at least in part, play an important role in MTX-stimulated cellular responses, such as activation of tTGase, ERK phosphorylation, and induction of cell death, in human umbilical vein endothelial cells.

• Molecules and Cells
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• v.26 no.4
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• pp.409-414
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• 2008

The cholesteryl ester transfer protein (CETP), a key player in cholesterol metabolism, has been shown to promote the transfer of triglycerides from very low density lipoprotein (VLDL) and low density lipoprotein (LDL) to high density lipoprotein (HDL) in exchange for cholesterol ester. Here we demonstrate that farnesoid X receptor ${\alpha}$ ($FXR{\alpha}$; NR1H4) down-regulates CETP expression in HepG2 cells. A $FXR{\alpha}$ ligand, chenodeoxycholic acid (CDCA), suppressed basal mRNA levels of the CETP gene in HepG2 cells in a dose-dependent manner. Using gel shift and chromatin immunoprecipitation (ChIP) assays, we found that $FXR{\alpha}$ could bind to the liver X receptor ${\alpha}$ ( $LXR{\alpha}$; NR1H3) binding site (LXRE; DR4RE) located within the CETP 5' promoter region. $FXR{\alpha}$ suppressed $LXR{\alpha}$-induced DR4RE-luciferase activity and this effect was mediated by a binding competition between $FXR{\alpha}$ and $LXR{\alpha}$ for DR4RE. Furthermore, the addition of CDCA together with a $LXR{\alpha}$ ligand, GW3965, to HepG2 cells was shown to substantially decrease mRNA levels of hepatic CETP gene, which is typically induced by GW3965. Together, our data demonstrate that $FXR{\alpha}$ down-regulates CETP gene expression via binding to the DR4RE sequence within the CETP 5' promoter and this $FXR{\alpha}$ binding is essential for $FXR{\alpha}$ inhibition of $LXR{\alpha}$-induced CETP expression.

• Molecules and Cells
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• v.23 no.3
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• pp.316-322
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• 2007

Zinc finger transcription factor genes are a significant fraction of the genes in the vertebrate genome. Here we report the isolation and characterization of a human zinc finger-containing gene, ZNF435, from a fetal brain cDNA library. ZNF435 cDNA is 1290 base pairs in length and contains an open reading frame encoding 349 amino acids with four C2H2-type zinc fingers at its carboxyl terminus and a SCAN motif at its amino terminus. RT-PCR results showed that ZNF435 was expressed in all tested tissues. A ZNF435-GFP fusion protein was located in the nucleus and the four zinc fingers acted as nuclear localization signals (NLSs). ZNF435 was found to be capable of homo-association, and this effect was independent of its zinc fingers. Furthermore, ZNF435 proved to be a transcription repressor as its overexpression in AD293 cells inhibited the transcriptional activities of AP-1.

• Molecules and Cells
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• v.40 no.5
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• pp.363-370
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• 2017

Extrahepatic cholangiocarcinoma (ECC), a malignant tumor of biliary origin, has a poor prognosis with limited treatment options. The KRAS oncogene is the most commonly mutated gene in ECC and one of the factors that predicts a poor prognosis and low survival rate. L1 cell adhesion molecule (L1CAM) is expressed in ECC cells and acts as an independent poor prognostic factor in predicting patient survival. In this study we investigate the functional significance of L1CAM in ECC cells with activating KRAS mutation. We selected an ECC cell line, EGI-1, with activating KRAS mutation, and then confirmed its expression of L1CAM by RT-PCR, western blot analysis, and flow cytometry. The suppression of L1CAM expression (using a specific lentivirus-delivered shRNA) significantly decreased the migratory and invasive properties of EGI-1 cells, without altering their proliferation or survival. Analyses of signaling effectors in L1CAM-depleted and control EGI-1 cells indicated that L1CAM suppression decreased the levels of both phosphorylated MKK4 and total MKK4, together with c-Jun N-terminal kinase (JNK) phosphorylation. Further, exposure to a JNK inhibitor (SP600125) decreased migration and invasion of EGI-1 cells. These results suggest that L1CAM promotes cellular migration and invasion via the induction of MKK4 expression, leading to JNK activation. Our study is the first to demonstrate a functional role for L1CAM in ECC carrying the activating KRAS mutation. Given that KRAS is the most commonly mutated oncogene in ECC, L1CAM may serve as an attractive therapeutic target for ECC cells with activating KRAS mutation.