• Toxicological Research
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• v.28 no.2
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• pp.107-112
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• 2012

Polychlorinated biphenyls (PCBs) are persistent and bioaccumulative environmental pollutants. Recently, it is suggested that neurotoxic effects such as motor dysfunction and impairment in memory and learning have been associated with PCB exposure. However, structure relationship of PCB congeners with neurotoxic effects remains unknown. Since PKC signaling pathway is implicated in the modulation of motor behavior as well as learning and memory and the role of PKC are subspecies-specific, we attempted to study the effects of structurally distinct PCBs on the total PKC activity as well as subspecies of PKC in cerebellar granule cell culture model. Cells were exposed to 0, 25 and 50 ${\mu}M$ of PCB-126, PCB-169, PCB-114, PCB-157, PCB-52 and PCB-4 for 15 min. Cells were subsequently analyzed by [$^3H$] phorbol ester binding assay or immunoblotted against PKC-${\alpha}$ and -${\varepsilon}$ monoclonal antibodies. While non-dioxin-like-PCB (PCB-52 and PCB-4) induced a translocation of PKC-${\alpha}$ and -${\varepsilon}$ from cytosol to membrane fraction, dioxin-like PCBs (PCB-126, -169, -114, -157) had no effects. [$^3H$] Phorbol ester binding assay also revealed structure-dependent increase similar to translocation of PKC isozymes. While PCB-4 induced translocation of PKC-${\alpha}$ and -${\varepsilon}$ was inhibited by ROS inhibitor, the pattern of translocation was not affected in presence of AhR inhibitor. It is suggested that PCB-4-induced PKC activity may not be mediated via AhR-dependent pathway. Taken together, our findings suggest that chlorination of ortho-position in PCB may be a critical structural moiety associated with neurotoxic effects, which may be preferentially mediated via non-AhR-dependent pathway. Therefore, the present study may contribute to understanding the neurotoxic mechanism of PCBs as well as providing a basis for establishing a better neurotoxic assessment.

• Clinical and Experimental Pediatrics
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• v.63 no.7
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• pp.239-250
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• 2020

The novel coronavirus disease 2019 (COVID-19) is spreading globally. Although its etiologic agent is discovered as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), there are many unsolved issues in COVID-19 and other infectious diseases. The causes of different clinical phenotypes and incubation periods among individuals, species specificity, and cytokine storm with lymphopenia as well as the mechanism of damage to organ cells are unknown. It has been suggested that in viral pneumonia, virus itself is not a direct cause of acute lung injury; rather, aberrant immune reactions of the host to the insults from viral infection are responsible. According to its epidemiological and clinical characteristics, SARS-CoV-2 may be a virus with low virulence in nature that has adapted to the human species. Current immunological concepts have limited ability to explain such unsolved issues, and a presumed immunopathogenesis of COVID-19 is presented under the protein-homeostasis-system hypothesis. Every disease, including COVID-19, has etiological substances controlled by the host immune system according to size and biochemical properties. Patients with severe pneumonia caused by SARS-CoV-2 show more severe hypercytokinemia with corresponding lymphocytopenia than patients with mild pneumonia; thus, early immunomodulator treatment, including corticosteroids, has been considered. However, current guidelines recommend their use only for patients with advanced pneumonia or acute respiratory distress syndrome. Since the immunopathogenesis of pneumonia may be the same for all patients regardless of age or severity and the critical immune-mediated lung injury may begin in the early stage of the disease, early immunomodulator treatment, including corticosteroids and intravenous immunoglobulin, can help reduce morbidity and possibly mortality rates of older patients with underlying conditions.

• BMB Reports
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• v.45 no.11
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• pp.641-646
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• 2012

It has been reported that ubiquitin-conjugating enzyme 9 (Ubc9), the unique enzyme2 in the sumoylation pathway, is up-regulated in many cancers. However, the expression and regulation of UBC9 in glioma remains unknown. In this study, we found that Ubc9 was up-regulated in glioma tissues and cell lines compared to a normal control. UBC9 knockdown by small interfering RNA (siRNA) affected cell proliferation and apoptosis in T98G cells. Further experiments revealed that microRNA (miR)-214 directly targeted the 3' untranslated region (UTR) of UBC9 and that there was an inverse relationship between the expression levels of miR-214 and UBC9 protein in glioma tissues and cells. miR-214 overexpression suppressed the endogenous UBC9 protein and affected T98G cell proliferation. These findings suggest that miR-214 reduction facilitates UBC9 expression and is involved in the regulation of glioma cell proliferation.

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.918-927
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• 2016

Cryptococcus neoformans is a life-threatening pathogenic yeast that causes devastating meningoencephalitis. The mechanism of cryptococcal brain invasion is largely unknown, and recent studies suggest that its extracellular microvesicles may be involved in the invasion process. The 14-3-3 protein is abundant in the extracellular microvesicles of C. neoformans, and the 14-3-3-GFP fusion has been used as the microvesicle's marker. However, the physiological role of 14-3-3 has not been explored. In this report, we have found that C. neoformans contains a single 14-3-3 gene that apparently is an essential gene. To explore the functions of 14-3-3, we substituted the promoter region of the 14-3-3 with the copper-controllable promoter CTR4. The CTR4 regulatory strain showed an enlarged cell size, drastic changes in morphology, and a decrease in the thickness of the capsule under copper-enriched conditions. Furthermore, the mutant cells produced a lower amount of total proteins in their extracellular microvesicles and reduced adhesion to human brain microvascular endothelial cells in vitro. Proteomic analyses of the protein components under 14-3-3-overexpressed and -suppressed conditions revealed that the 14-3-3 function(s) might be associated with the microvesicle biogenesis. Our results support that 14-3-3 has diverse pertinent roles in both physiology and pathogenesis in C. neoformans. Its gene functions are closely relevant to the pathogenesis of this fungus.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.96-96
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• 2003

Nek2 (NIMA-related protein) is a mammalian cell cycle-regulated kinase that involves in chromosome condensation and centrosome regulation and NuMA (nuclear mitotic apparatus protein) is involved in spindle assembly during a cell cycle. The cellular distribution and organization of the centrosomal components is completely unknown during fertilization and embryonic development. We examined distribution of two well-known centrosomal proteins, Nek2 and NuMA in mouse gametes and embryos to get an insight in the reorganization of centrosomal proteins during germ cell development and early fertilization. Spermatogenic cells, gametes, and embryos were analyzed with anti-Nek2 or -NuMA antibodies by immunological assay, RT-PCR, and overexpression through gene transfection. Mitotically or meiotically active spermatogenic cells were intensively stained with these antibodies in both centrosomes and cytoplasm, whereas the oocytes showed different staining patterns depending on the meiotic stages. During maturation, GV, GVBD, and MI stage were clearly stained with NuMA antibody in the nucleus or cytoplasm at MII. Also, Nek2 was detectable in cytoplasm as scattered spots or chromosome associated at MII. In early developmental embryo, NuMA was detected in nucleus of each blastomere, while Nek2 was detected in cytoplasm. In contrast to previously reported results, Nek2 and NuMA were detected in both decondensing head, and the centriole of demembranated and decondensed sperm or whole body of trypsin-treated sperm for Nek2. During meiotic progress in oocytes, transcripts levels were the highest in MI stage and then downregulated in MII. Also, it shows dramatically change in early developmental embryos, firstly, it was increased until 4 cell stage and reduced in 8 cell stage, and finally, transcript levels were upregulated until blastoscyst. This finding suggests that cnetrosomal component may play an important role in reorganizing of functional centrosome during fertilization process and subsequent development.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.624-632
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• 2017

Penicillium expansum causes blue mold rot, a prevalent postharvest disease of pome fruit, and is also the main producer of the patulin. However, knowledge on the molecular mechanisms involved in this pathogen-host interaction remains largely unknown. In this work, a two-dimensional gel electrophoresis-based proteomic approach was applied to probe changes in P. expansum 3.3703 cultivated in apple juice medium, which was used to mimic the in planta condition. The results showed that the pH value and reducing sugar content in the apple juice medium decreased whereas the patulin content increased with the growing of P. expansum. A total of 28 protein spots that were up-regulated in P. expansum when grown in apple juice medium were identified. Functional categorization revealed that the identified proteins were mainly related to carbohydrate metabolism, secondary metabolism, protein biosynthesis or degradation, and redox homeostasis. Remarkably, several induced proteins, including glucose dehydrogenase, galactose oxidase, and FAD-binding monooxygenase, which might be responsible for the observed medium acidification and patulin production, were also detected. Overall, the experimental results provide a comprehensive interpretation of the physiological and proteomic responses of P. expansum to the host plant environment, and future functional characterization of the identified proteins will deepen our understanding of fungi-host interactions.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1261-1271
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• 2020

Cytochrome c_L (Cytc_L) is an essential protein in the process of methanol oxidation in methylotrophs. It receives an electron from the pyrroloquinoline quinone (PQQ) cofactor of methanol dehydrogenase (MDH) to produce formaldehyde. The direct electron transfer mechanism between Cytc_L and MDH remains unknown due to the lack of structural information. To help gain a better understanding of the mechanism, we determined the first crystal structure of heme c containing Cytc_L from the aquatic methylotrophic bacterium Methylophaga aminisulfidivorans MP^T at 2.13 Å resolution. The crystal structure of Ma-Cytc_L revealed its unique features compared to those of the terrestrial homologues. Apart from Fe in heme, three additional metal ion binding sites for Na⁺, Ca⁺, and Fe²⁺ were found, wherein the ions mostly formed coordination bonds with the amino acid residues on the loop (G93-Y111) that interacts with heme. Therefore, these ions seemed to enhance the stability of heme insertion by increasing the loop's steadiness. The basic N-terminal end, together with helix α4 and loop (G126 to Y136), contributed positive charge to the region. In contrast, the acidic C-terminal end provided a negatively charged surface, yielding several electrostatic contact points with partner proteins for electron transfer. These exceptional features of Ma-Cytc_L, along with the structural information of MDH, led us to hypothesize the need for an adapter protein bridging MDH to Cytc_L within appropriate proximity for electron transfer. With this knowledge in mind, the methanol oxidation complex reconstitution in vitro could be utilized to produce metabolic intermediates at the industry level.

• Journal of Korean Neurosurgical Society
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• v.49 no.1
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• pp.43-48
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• 2011

Objective: Classical markers of infection cannot differentiate reliably between inflammation and infection after neurosurgery. This study investigated the dynamics of serum procalcitonin (PCT) in patients who had elective spine surgeries without complications. Methods: Participants were 103 patients (47 women, 56 men) who underwent elective spinal surgery. Clinical variables relevant to the study included age, sex, medical history, body mass index (BMI), site and type of surgery, and surgery duration. Clinical and laboratory data were body temperature, white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and PCT, all measured preoperatively and postoperatively on days 1, 3, and 5. Results: PCT concentrations remained at <0.25 ng/mL during the postoperative course except in 2 patients. PCT concentrations did not correlate with age, sex, DM, hypertension, BMI, operation time, operation site, or use of instrumentation. In contrast, CRP concentrations were significantly higher with older age, male, DM, hypertension, longer operation time, cervical operation, and use of instrumentation. Conclusion: PCT may be useful in the diagnosing neurosurgical patients with postoperative fever of unknown origin.

• Molecules and Cells
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• v.39 no.8
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• pp.625-630
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• 2016

The RNA-binding protein Rbfox3 is a well-known splicing regulator that is used as a marker for post-mitotic neurons in various vertebrate species. Although recent studies indicate a variable expression of Rbfox3 in non-neuronal tissues, including lung tissue, its cellular function in lung cancer remains largely unknown. Here, we report that the number of RBFOX3-positive cells in tumorous lung tissue is lower than that in normal lung tissue. As the transforming growth factor-${\beta}$ (TGF-${\beta}$) signaling pathway is important in cancer progression, we investigated its role in RBFOX3 expression in A549 lung adenocarcinoma cells. TGF-${\beta}1$ treatment inhibited RBFOX3 expression at the transcriptional level. Further, RBFOX3 depletion led to a change in the expression levels of a subset of proteins related to epithelial-mesenchymal transition (EMT), such as E-cadherin and Claudin-1, during TGF-${\beta}1$-induced EMT. In immunofluorescence microscopic analysis, mesenchymal morphology was more prominent in RBFOX3-depleted cells than in control cells. These findings show that TGF-${\beta}$-induced RBFOX3 inhibition plays an important role in EMT and propose a novel role for RBFOX3 in cancer progression.

• Molecules and Cells
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• v.38 no.7
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• pp.638-642
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• 2015

Quercetin can suppress osteosarcoma cell growth and metastasis. However, other effects of quercetin on osteosarcoma remain largely unknown. This research aims to evaluate the effects of quercetin in combination with cisplatin as treatment for osteosarcoma and investigate its regulatory mechanism. Cell viability and apoptosis in 143B cell line were determined after treatment with quercetin and/or cisplatin. RT-PCR and Western blot analysis were performed to determine the RNA or protein expression levels. Moreover, transwell assay was used to evaluate metastasis. Furthermore, rescue experiments were performed to investigate the potential regulatory mechanism of the treatment. Results showed that quercetin with concentration that was equal to or greater than $10{\mu}M$ inhibited 143B proliferation, while $5{\mu}M$ quercetin enhanced the cisplatin sensitivity of 143B cells. Expression of miR-217 was upregulated after quercetin and/or cisplatin treatment, while its target KRAS was downregulated both at mRNA and protein levels. MiR-217 knockdown led to the loss of enhanced cisplatin sensitivity while miR-217 overexpression showed the opposite effects, indicating that quercetin regulated cisplatin sensitivity by modulating the miR-217-KRAS axis. In conclusion, $5{\mu}M$ quercetin enhanced the cisplatin sensitivity by modulating the miR-217-KRAS axis. This finding suggests that quercetin may be administered with cisplatin to improve the treatment for osteosarcoma.