• Journal of Ginseng Research
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• v.43 no.2
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• pp.218-225
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• 2019

Background: Streptococcus pneumoniae, more than 90 serotypes of which exist, is recognized as an etiologic agent of pneumonia, meningitis, and sepsis associated with significant morbidity and mortality worldwide. Immunization with a pneumococcal pep27 mutant (${{\Delta}}pep27$) has been shown to confer comprehensive, long-term protection against even nontypeable strains. However, ${{\Delta}}pep27$ is effective as a vaccine only after at least three rounds of immunization. Therefore, treatments capable of enhancing the efficiency of ${{\Delta}}pep27$ immunization should be identified without delay. Panax ginseng Mayer has already been shown to have pharmacological and antioxidant effects. Here, the ability of Korean Red Ginseng (KRG) to enhance the efficacy of ${{\Delta}}pep27$ immunization was investigated. Methods: Mice were treated with KRG and immunized with ${{\Delta}}pep27$ before infection with the pathogenic S. pneumoniae strain D39. Total reactive oxygen species production was measured using lung homogenates, and inducible nitric oxide (NO) synthase and antiapoptotic protein expression was determined by immunoblotting. The phagocytic activity of peritoneal macrophages was also tested after KRG treatment. Results: Compared with the other treatments, KRG significantly increased survival rate after lethal challenge and resulted in faster bacterial clearance via increased phagocytosis. Moreover, KRG enhanced ${{\Delta}}pep27$ vaccine efficacy by inhibiting reactive oxygen species production, reducing extracellular signal-regulated kinase apoptosis signaling and inflammation. Conclusion: Taken together, our results suggest that KRG reduces the time required for immunization with the ${{\Delta}}pep27$ vaccine by enhancing its efficacy.

• IMMUNE NETWORK
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• v.20 no.5
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• pp.36.1-36.13
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• 2020

Hippo signaling pathways are evolutionarily conserved signal transduction mechanisms mainly involved in organ size control, tissue regeneration, and tumor suppression. However, in mammals, the primary role of Hippo signaling seems to be regulation of immunity. As such, humans with null mutations in STK4 (mammalian homologue of Drosophila Hippo; also known as MST1) suffer from recurrent infections and autoimmune symptoms. Although dysregulated T cell homeostasis and functions have been identified in MST1-deficient human patients and mouse models, detailed cellular and molecular bases of the immune dysfunction remain to be elucidated. Although the canonical Hippo signaling pathway involves transcriptional co-activator Yes-associated protein (YAP) or transcriptional coactivator with PDZ motif (TAZ), the major Hippo downstream signaling pathways in T cells are YAP/TAZ-independent and they widely differ between T cell subsets. Here we will review Hippo signaling mechanisms in T cell immunity and describe their implications for immune defects found in MST1-deficient patients and animals. Further, we propose that mutual inhibition of Mst and Akt kinases and their opposing roles on the stability and function of forkhead box O and β-catenin may explain various immune defects discovered in mutant mice lacking Hippo signaling components. Understanding these diverse Hippo signaling pathways and their interplay with other evolutionarily-conserved signaling components in T cells may uncover molecular targets relevant to vaccination, autoimmune diseases, and cancer immunotherapies.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.311-319
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• 2023

Caveolin-1 (Cav-1) is the main structural component of the caveolae on the plasma membrane, which regulates various cellular processes, including cell growth, differentiation, and endocytosis. Although a recent study demonstrated that Cav-1 might be involved in diabetes-associated inflammation, its exact role in the intestine was unclear. In this study, we examined the intestinal expression of Cav-1 in diabetic conditions. We also investigated its effect on lipopolysaccharide (LPS)-induced inflammation by expressing this protein in human intestinal Caco-2 cells lacking Cav-1. We observed that increased Cav-1 levels and decreased expression of tight junction proteins affected intestinal permeability in high-fat diet-induced diabetic mice. When Caco-2 cells were treated with LPS, Cav-1 enhanced the NF-κB signaling. Moreover, LPS reduced the expression of tight junction proteins while it increased cell-cell permeability and reactive oxygen species generation in Caco-2 cells and this effect was amplified by cav-1 overexpression. LPS treatment promoted phosphorylation of tyrosine-14 (Y14) on Cav-1, and the LPS-induced NF-κB signaling was suppressed in cells expressing non-phosphorylatable Cav-1 (tyrosine-14 to phenylalanine mutant), which reduced intestinal barrier permeability. These results suggest that Cav-1 expression promotes LPS-induced inflammation in Caco-2 cells, and phosphorylation of Y14 on Cav-1 might contribute to the anti-inflammatory response in LPS-induced NF-κB signaling and cell permeability.

• Journal of Microbiology and Biotechnology
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• v.34 no.8
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• pp.1592-1598
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• 2024

Genotype V (GV) Japanese encephalitis virus (JEV) has been predominantly reported in the Republic of Korea (ROK) since 2010. GV JEV exhibits higher virulence and distinct antigenicity compared to other genotypes, which results in reduced efficacy of existing vaccines. Research on GV JEV is essential to minimize its clinical impact, but the only available clinical strain in the ROK is K15P38, isolated from the cerebrospinal fluid of a patient in 2015. We obtained this virus from National Culture Collection for Pathogens (NCCP) and isolated a variant forming small plaques during our research. We identified that this variant has one amino acid substitution each in the PrM and NS5 proteins compared to the reported K15P38. Additionally, we confirmed that this virus exhibits delayed propagation in vitro and an attenuated phenotype in mice. The isolation of this variant is a critical reference for researchers intending to study K15P38 obtained from NCCP, and the mutations in the small plaque-forming virus are expected to be useful for studying the pathology of GV JEV.

• The Journal of the Korean Society for Microbiology
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• v.35 no.3
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• pp.251-261
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• 2000

V. vulnificus is an estuarine bacterium which causes septicemia and shock in susceptible patients. The organism produces a hemolytic cytolysin (VvH), which has a membrane damaging effect on erythrocytes. To clarify the mechanisms by which VvH might contribute to virulence, we examined its effect on macrophages. When mouse peritoneal macrophages were harvested and co-cultured with hemolysin-positive V. vulnificus strains (100 bacteria/cell), about 60% of the macrophages were killed; macrophages were not killed when co-cultured V. vulnificus strain CVD 707, a VvH-negative deletion mutant. Exposure of macrophages to filtered culture supernatants (2.5 HU/ml) and purified VvH (3 HU/ml) resulted in an increase in dead cells (80 and 90%, respectively), as determined by the trypan blue dye exclusion method and LDH release from macrophages was also increased (70 and 65.5%, respectively). The cytotoxic effect of VvH on macrophages was both the dose- and time-dependent. The VvH caused damage to the macrophage membrane and was blocked significantly by preincubation with cholesterol (p<0.01). Fetal bovine serum showed remarkable inhibition of VvH synthesis by V. vulnificus and inhibited VvH activity in culture supernatant. Cell viability was increased by 35% (p<0.01) and LDH release decreased by 28% (p<0.01) when macrophages were incubated with V. vulnificus (100 bacterial cell) in DMEM-10% FBS for 2 hr. Bacterial clearance activity of mice against V. vulnificus CVD 707 was decreased by pretreatment with 10 HU of VvH. This result suggests that the VvH can impair the membrane of macrophages and may playa role in the pathogenesis of V. vulnificus septicemia.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1045-1052
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• 2017

In this study, a battery of genetic-toxicity studies on corn silk extract with high maysin content were performed according to internationally accepted protocols. In a mutation test using Salmonella Typhimurium TA1535, TA1537, TA98, and TA100, the number of mutant colonies did not significantly increase up to a maximum concentration of $5,000{\mu}g/plate$ in the presence or absence of the S9 metabolic activation system. In the chromosome aberration test using Chinese hamster lung fibroblasts, negative results were observed in the concentration up to $1,250{\mu}g/mL$ of corn silk extract. In the micronucleus test using ICR mice, incidence of polymorphonuclear erythrocytes with a maximum concentration of 2,000 mg/kg corn silk extract did not show any significant difference compared to the negative control group. Based on these results, the test substance, con silk extract, did not influence genotoxicity.

• Nutrition Research and Practice
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• v.4 no.5
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• pp.351-355
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• 2010

Our previous proteomic study demonstrated that oxidative stress and antioxidant delphinidin regulated the cellular level of $p27^{kip1}$ (referred to as p27) as well as some heat shock proteins in human colon cancer HT 29 cells. Current study was conducted to validate and confirm the regulation of these proteins using both in vitro and in vivo systems. The level of p27 was decreased by hydrogen peroxide in a dose-dependent manner in human colon carcinoma HCT 116 (p53-positive) cells while it was increased upon exposure to hydrogen peroxide in HT 29 (p53-negative) cells. However, high concentration of hydrogen peroxide (100 ${\mu}M)$ downregulated p27 in both cell lines, but delphindin, one of antioxidative anthocyanins, enhanced the level of p27 suppressed by 100 ${\mu}M$ hydrogen peroxide. ICR mice were injected with varying concentrations of hydrogen peroxide, delphinidin and both. Western blot analysis for the mouse large intestinal tissue showed that the expression of p27 was upregulated by 25 mg/kg BW hydrogen peroxide. To investigate the association of p27 regulation with hypoxia-inducible factor 1-beta (HIF-$1{\beta}$), the level of p27 was analyzed in wild-type mouse hepatoma hepa1c1c7 and Aryl Hydrocarbon Nuclear Translocator (arnt, HIF-$1{\beta}$)-defective mutant BPRc1 cells in the absence and presence of hydrogen peroxide and delphinidin. While the level of p27 was responsive to hydrogen peroxide and delphinidin, it remained unchanged in BPRc1, suggesting that the regulation of p27 requires functional HIF-$1{\beta}$. We also found that hydrogen peroxide and delphinidin affected PI3K/Akt/mTOR signaling pathway which is one of upstream regulators of HIFs. In conclusion, hydrogen peroxide and antioxidant delphinidin seem to regulate intracellular level of p27 through regulating HIF-1 level which is, in turn, governed by its upstream regulators comprising of PI3K/Akt/mTOR signaling pathway. The results should also encourage further study for the potential of p27 as a biomarker for intracellular oxidative or antioxidant status.

• Korean Journal of Veterinary Research
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• v.39 no.2
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• pp.247-256
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• 1999

A disease of young Holstein calves characterized by recurrent pneumonia, ulcerative and granulomatous stomatitis, enteritis with bacterial overgrowth, periodontitis, delayed wound healing, persistent neutrophilia and death at an early age had been originally described in 1983 and again in 1987. Most of these calves had stunted growth and a persistent, progressive neutrophilia (often exceeding 100,000/ml). By investigation of pedigrees, all of the affected calves have now been traced to a common sire and confirmed by polymerase chain reaction (PCR) diagnostic DNA testing to be homozygous carriers of a defective allele for bovine CD18. Neutrophils from these calves have several functional deficits and, most importantly, fail to adhere in a ${\beta}_2$-integrin dependent manner. The ${\beta}_2$-integrins represent a family of glycoproteins which participate in various leukocyte adhesion reactions during host defense. The presence or absence of ${\beta}_2$-integrin molecules can be demonstrated on the surface of neutrophils, monocytes and lymphocytes from normal or affected calves using specific monoclonal antibodies and flow cytometry, or by colloidal gold immunolabeling and scanning electron microscopy in backscatter mode. Deficiency of the ${\beta}_2$-integrins on all leukocyte types in Holstein calves is analogous to leukocyte adhesion deficiency (LAD) seen in humans. Neutrophils in bovine (BLAD) and human LAD patients are unable to adhere to the endothelial lining of the cardiovascular system thus interrupting egression of neutrophils into infected tissues. Other leukocytes, while still deficient in expression of the ${\beta}_2$-integrins, are still able to efficiently egress from the blood stream due to interactions of other adhesion molecules that are not as highly expressed on neutrophils. Both BLAD cattle and LAD children (who do not receive bone marrow transplants) often die at an early age as a result of the failure of neutrophils to extravasate into infected tissues. In 1991, Shuster, et $al^{27}$, identified two point mutations within the alleles encoding bovine CD18 in a Holstein calf afflicted with leukocyte adhesion deficiency. One mutation causes an aspartic acid to glycine substitution at amino acid 128 (D128G) in an extracellular region of this adhesion glycoprotein that is highly conserved (> 95% identity) between humans, cattle and mice. The other mutation is silent. Numerous calves with clinical symptoms of leukocyte adhesion deficiency have since been tested and all have been found homozygous for the D128G allele. In addition, calves homozygous far the D128G allele have been identified during widespread DNA testing in the United States. All cattle with the mutant allele are related to one bull, who through artificial insemination (A.I.), sired many calves in the 1950's and 1960's. The carrier frequency of the D128G CD18 allele among U.S. Holstein cattle had reached approximately 15% among active A.I. bulls and 8% among cows. By 1993, the organization of the dairy industry and the diagnostic test developed to genotype cattle, enabled virtually complete eradication of bovine leukocyte adhesion deficiency among current and future A.I. bulls.

• Korean Journal of Optics and Photonics
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• v.33 no.6
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• pp.331-337
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• 2022

Raman spectroscopy is an optical technique that can identify molecules in a label-free manner, and is therefore heavily investigated in various areas ranging from biomedical engineering to materials science. Probe-based Raman spectroscopy can perform minimally invasive chemical analysis, and thus has potential as a real-time diagnostic tool during surgery. In this study, Raman experimentation was calibrated by examining the Raman shifts with respect to the concentrations of chemical substances. Raman signal characteristics, targeted for normal mice and cerebral tissues of the 5xFAD dementia mutant model with accumulated amyloid beta plaques, were measured and analyzed to explore the possibility of diagnosis of Alzheimer's disease. The application to the diagnosis of dementia was cross-validated by measuring Raman signals of amyloid beta. The results suggest the potential of Raman spectroscopy as a diagnostic tool that may be useful in various areas of application.

• Biomolecules & Therapeutics
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• v.32 no.4
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• pp.481-491
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• 2024

Paxlovid is the first approved oral treatment for coronavirus disease 2019 and includes nirmatrelvir, a protease inhibitor targeting the main protease (M^pro) of SARS-CoV-2, as one of the key components. While some specific mutations emerged in M^pro were revealed to significantly reduce viral susceptibility to nirmatrelvir in vitro, there is no report regarding resistance to nirmatrelvir in patients and animal models for SARS-CoV-2 infection yet. We recently developed xenograft tumors derived from Calu-3 cells in immunodeficient mice and demonstrated extended replication of SARS-CoV-2 in the tumors. In this study, we investigated the effect of nirmatrelvir administration on SARS-CoV-2 replication. Treatment with nirmatrelvir after virus infection significantly reduced the replication of the parental SARS-CoV-2 and SARS-CoV-2 Omicron at 5 days post-infection (dpi). However, the virus titers were completely recovered at the time points of 15 and 30 dpi. The virus genomes in the tumors at 30 dpi were analyzed to investigate whether nirmatrelvir-resistant mutant viruses had emerged during the extended replication of SARS-CoV-2. Various mutations in several genes including ORF1ab, ORF3a, ORF7a, ORF7b, ORF8, and N occurred in the SARS-CoV-2 genome; however, no mutations were induced in the M^pro sequence by a single round of nirmatrelvir treatment, and none were observed even after two rounds of treatment. The parental SARS-CoV-2 and its sublineage isolates showed similar IC₅₀ values of nirmatrelvir in Vero E6 cells. Therefore, it is probable that inducing viral resistance to nirmatrelvir in vivo is challenging differently from in vitro passage.