• Molecules and Cells
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• v.37 no.1
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• pp.66-73
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• 2014

Myeloid-derived suppressor cells (MDSCs) play an important role in impairing the function of T cells. We characterized MDSCs in two chronic hepatitis C (CHC) cohorts: a cross-sectional group that included 61 treatment-naive patients with CHC, 14 rapid virologic response (RVR) cases and 22 early virologic response (EVR) cases; and a longitudinal group of 13 cases of RVR and 10 cases of EVR after pegylated-interferon-${\alpha}$/ribavirin treatment for genotype 1b HCV infection. Liver samples from 32 CHC patients and six healthy controls were subjected to immunohistochemical analysis. MDSCs frequency in treatment-naive CHC was significantly higher than in RVR, EVR, or healthy subjects and was positively correlated with HCV RNA. Patients infected with HCV genotype 2a had a significantly higher frequency of MDSCs than those infected with genotype 1b. Decreased T cell receptor (TCR) ${\zeta}$ expression on $CD8^+$ T cells was significantly associated with an increased frequency of MDSCs in treatment-naive CHC patients and was restored by L-arginine treatment in vitro. Increased numbers of liver arginase-$1^+$ cells were closely associated with the histological activity index in CHC. The TCR ${\zeta}$ chain was significantly downregulated on hepatic $CD8^+$ T cells in CHC. During antiviral follow up, MDSCs frequency in peripheral blood mononuclear cells was directly correlated with the HCV RNA load in the plasma and inversely correlated with TCR ${\zeta}$ chain expression in $CD8^+$ T cells in both RVR and EVR cases. Notably, the RVR group had a higher frequency of MDSCs at baseline than the EVR group. Collectively, this study provides evidence that MDSCs might be associated with HCV persistence and downregulation of CD8 ${\zeta}$ chain expression.

• Journal of fish pathology
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• v.31 no.1
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• pp.9-13
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• 2018

We previously monitored nervous necrosis virus (NNV) in brain samples of artificially produced walleye Pollock (Gadus chalcogrammus) seedlings, with a low prevalence (1.8%, 1/55) but no clinical symptoms. Given that this virus is considered one of the most serious viral threats for almost all marine aquaculture fish species and characterized by both vertical and horizontal transmission, it would be interesting to monitor NNV in the fertilized eggs as well. We collected fertilized walleye pollock eggs from the farms located in Goseong during January to March, 2017. Approximately 50 mg of eggs were periodically taken from 4 each different batches, and 37 different pooled sample sets in total were made during sampling period. RNA was extracted from the eggs by using Trizol and cDNA was synthesized for RT-PCR for detecting NNV. Primers and PCR conditions are the same as previously described. As a result, NNV was not detected from any of the sample sets by one step PCR (0%, 0/37), suggesting NNV may not be a threat in walleye pollock aquaculture in Korea at present time. However, continuous monitoring for NNV should be conducted because introducing a new species into aquaculture industry involves potentials of disease outbreak and NNV is already known to cause outbreaks in gadoid fishes.

• Molecules and Cells
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• v.44 no.3
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• pp.146-159
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• 2021

DNA methylation, and consequent down-regulation, of tumour suppressor genes occurs in response to epigenetic stimuli during cancer development. Similarly, human oncoviruses, including human papillomavirus (HPV), up-regulate and augment DNA methyltransferase (DNMT) and histone deacetylase (HDAC) activities, thereby decreasing tumour suppressor genes (TSGs) expression. Ubiquitin-like containing PHD and RING finger domain 1 (UHRF1), an epigenetic regulator of DNA methylation, is overexpressed in HPV-induced cervical cancers. Here, we investigated the role of UHRF1 in cervical cancer by knocking down its expression in HeLa cells using lentiviral-encoded short hairpin (sh)RNA and performing cDNA microarrays. We detected significantly elevated expression of thioredoxin-interacting protein (TXNIP), a known TSG, in UHRF1-knockdown cells, and this gene is hypermethylated in cervical cancer tissue and cell lines, as indicated by whole-genome methylation analysis. Up-regulation of UHRF1 and decreased TXNIP were further detected in cervical cancer by western blot and immunohistochemistry and confirmed by Oncomine database analysis. Using chromatin immunoprecipitation, we identified the inverted CCAAT domain-containing UHRF1-binding site in the TXNIP promoter and demonstrated UHRF1 knockdown decreases UHRF1 promoter binding and enhances TXNIP expression through demethylation of this region. TXNIP promoter CpG methylation was further confirmed in cervical cancer tissue by pyrosequencing and methylation-specific polymerase chain reaction. Critically, down-regulation of UHRF1 by siRNA or UHRF1 antagonist (thymoquinone) induces cell cycle arrest and apoptosis, and ubiquitin-specific protease 7 (USP7), which stabilises and promotes UHRF1 function, is increased by HPV viral protein E6/E7 overexpression. These results indicate HPV might induce carcinogenesis through UHRF1-mediated TXNIP promoter methylation, thus suggesting a possible link between CpG methylation and cervical cancer.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.2
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• pp.79-94
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• 2022

Due to the highly contagious nature and severity of the respiratory diseases caused by COVID-19, economical and accurate tests are required to better monitor and prevent the spread of this contagion. As the structural and molecular properties of SARS-CoV-2 were being revealed during the early stage of the COVID-19 pandemic, many manufacturers of COVID-19 diagnostic kits actively invested in the design, development, validation, verification, and implementation of diagnostic tests. Currently, diagnostic tests for SARS-CoV-2 are the most widely used and validated techniques for rapid antigen, and immuno-serological assays for specific IgG and IgM antibody tests and molecular diagnostic tests. Molecular diagnostic assays are the gold standard for direct detection of viral RNA in individuals suspected to be infected with SARS-CoV-2. Antibody-based serological tests are indirect tests applied to determine COVID-19 prevalence in the community and identify individuals who have obtained immunity. In the future, it is necessary to explore technical problems encountered in the early stages of global or regional outbreaks of pandemics and provide future directions for better diagnostic tests. This article evaluates the commercially available and FDA-approved molecular and immunological diagnostic assays and analyzes their performance characteristics.

• Animal Bioscience
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• v.36 no.1
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• pp.43-52
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• 2023

Objective: This study aimed to examine the influence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on pregnancy in cytokeratin-18 (K18)-hACE2 transgenic mice. Methods: To determine the expression of hACE2 mRNA in the female reproductive tract of K18-hACE2 mice, real-time polymerase chain reaction (RT-PCR) was performed using the ovary, oviduct, uterus, umbilical cord, and placenta. SARS-CoV-2 was inoculated intranasally (30 μL/mouse, 1×10⁴ TCID₅₀/mL) to plug-checked K18-hACE2 homozygous female mice at the pre-and post-implantation stages at 2.5 days post-coitum (dpc) and 15.5 dpc, respectively. The number of implantation sites was checked at 7.5 dpc, and the number of normally born pups was investigated at 20.5 dpc. Pregnancy outcomes, including implantation and childbirth, were confirmed by comparison with the non-infected group. Tissues of infected mice were collected at 7.5 dpc and 19.5 dpc to confirm the SARS-CoV-2 infection. The infection was identified by performing RT-PCR on the infected tissues and comparing them to the non-infected tissues. Results: hACE2 mRNA expression was confirmed in the female reproductive tract of the K18-hACE2 mice. Compared to the non-infected group, no significant difference in the number of implantation sites or normally born pups was found in the infected group. SARS-CoV-2 infection was detected in the lungs but not in the female reproductive system of infected K18-hACE2 mice. Conclusion: In K18-hACE2 mice, intranasal infection with SARS-CoV-2 did not induce implantation failure, preterm labor, or miscarriage. Although the viral infection was not detected in the uterus, placenta, or fetus, the infection of the lungs could induce problems in the reproductive system. However, lung infections were not related to pregnancy outcomes.

• Journal of Life Science
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• v.32 no.2
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• pp.94-100
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• 2022

Chronic infection by hepatitis B virus (HBV) greatly increases the risk for liver cirrhosis and hepatocellular carcinoma (HCC). The outcome of HBV infection is shaped by the complex interplay of the mode of transmission, host genetic factors, viral genotype, adaptive mutations, and environmental factors. The pregenomic RNA transcription of HBV for their replication is regulated by the core promoter activation. Core promoter mutations have been the reason for acute liver failure and are associated with HCC development. We obtained HBV genes from a patient in Myanmar who was infected with HBV and identified gene variations in the core promoter region. For measuring the relative transactivation activity of the core promoter, we prepared the core-promoter reporter construct. Among the gene variations of the core promoter, the mutations of C1731T and G1806A were associated with increase in the transactivation of the HBV core promoter. Through computer analysis for searching for a tentative transcription factor binding site, we showed that the mutations of C1713T and G1806A newly created C/EBPβ and XBP1-responsive elements of the core promoter, respectively. The ectopic expression of C/EBPβ largely increased the HBV core promoter containing the C1713T mutation and that of XBP1 activated the M95 promoter containing the G1806A mutation. Our efforts to treat and prevent HBV infections are hampered by the emergence of drug-resistant mutations and vaccine-escape mutations. Our results provide the biological properties and clinical significance of specific HBV core promoter mutations.

• BMB Reports
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• v.55 no.9
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• pp.465-471
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• 2022

Understanding and monitoring virus-mediated infections has gained importance since the global outbreak of the coronavirus disease 2019 (COVID-19) pandemic. Studies of high-throughput omics-based immune profiling of COVID-19 patients can help manage the current pandemic and future virus-mediated pandemics. Although COVID-19 is being studied since past 2 years, detailed mechanisms of the initial induction of dynamic immune responses or the molecular mechanisms that characterize disease progression remains unclear. This study involved comprehensively collected biospecimens and longitudinal multi-omics data of 300 COVID-19 patients and 120 healthy controls, including whole genome sequencing (WGS), single-cell RNA sequencing combined with T cell receptor (TCR) and B cell receptor (BCR) sequencing (scRNA(+scTCR/BCR)-seq), bulk BCR and TCR sequencing (bulk TCR/BCR-seq), and cytokine profiling. Clinical data were also collected from hospitalized COVID-19 patients, and HLA typing, laboratory characteristics, and COVID-19 viral genome sequencing were performed during the initial diagnosis. The entire set of biospecimens and multi-omics data generated in this project can be accessed by researchers from the National Biobank of Korea with prior approval. This distribution of large-scale multi-omics data of COVID-19 patients can facilitate the understanding of biological crosstalk involved in COVID-19 infection and contribute to the development of potential methodologies for its diagnosis and treatment.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.2
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• pp.57-61
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• 2006

Suppressor of cytokine signaling (SOCS) is known to be as a negative feedback regulator in Janus kinase signal transducer and activator of transcription signaling. Highly conserved SOCS box domain was cloned from a Korean malaria vector, Anopheles sinensis. Sequence analysis indicates that it has identity to Anopheles gambiae (96%), Aedes aegypti (94%), Drosophila melanogaster (78%), Mus musculus (72%) and Homo sapiens (72%), respectively. Tissue specificity RT-PCR demonstrated that the expression level of AsSOCS transcript was high at abdomen, midgut, and ovary, whereas developmental expression patterns showed that the level of AsSOCS was high at egg, early pupae, and adult female. On the other hand, RT-PCR analysis after bacterial challenge showed that SOCS mRNA was strongly induced in larvae. In addition, it was also induced by various immune elicitors such as lipoteicoic acid, CpG-DNA, and laminarin. It seems that AsSOCS, repressor of JAK-STAT pathway, is highly conserved in mosquito, and may play an important role in mosquito innate immune response.

• Korean Journal of Medicinal Crop Science
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• v.17 no.2
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• pp.133-138
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• 2009

Nelumbo nucifera (lotus) is known to be a useful medicinal plant and leaf extract contains several flavonoids and alkaloids. To analyze the effect of Nelumbo nucifera leaves extract (NNL) on the HBsAg production, we treated NNL on HepG2.2.15 cells which contain the hepatitis B viral genome and secrete surface antigen into media. NNL suppressed the production of hepatitis B surface antigen as a dose-dependent manner. To analyze the effect of NNL on HBV DNA replication, PCR analysis was performed. NNL was not affected the HBV DNA replication and HBsAg mRNA expression. To understand the effect of NNL on the production of HBsAg, we carried out the analysis of lipid-metabolizing gene expression using one-step RT-PCR. NNL reduced the gene expression of FASN and SREBP2 and increased the expression of LDLR. Triglyceride content of HepG2.2.15 cells was not decreased by treatment of NNL. This result suggests a possibility that NNL may have an effect for the inhibition of hepatitis B surface antigen by modulation of lipid and cholesterol metabolism.

• Molecules and Cells
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• v.26 no.5
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• pp.496-502
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• 2008

Cryparin, encoded as a single copy gene (Crp) of the chestnut blight fungus Cryphonectria parasitica, is the most abundant protein produced by this fungus. However, its accumulation is decreased remarkably in C. parastica strains containing the double-stranded (ds) RNA virus Cryphonectria hypovirus 1. To characterize the transcriptional regulatory element(s) for strong expression and viral regulation, promoter analysis was conducted. Serial deletion of the Crp promoter region resulted in a step-wise decrease in promoter activity, indicating a localized distribution of genetic elements in the cryparin promoter. Promoter analysis indicated two positive and a repressive cis-acting elements. Among them, the promoter region between nt -1,282 and -907 appeared to be necessary for hypoviral-mediated down-regulation. An electrophoretic mobility shift assay (EMSA) on the corresponding promoter region (-1,282/-907) indicated two regions at (-1,257/-1,158) and (-1,107/-1,008) with the characteristic AGGAGGA-N42-GAGAGGA and its inverted repeat TCCTCTC-N54-TCCTCCT, respectively, appeared to be specific binding sites for cellular factors.