• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.2
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• pp.144-153
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• 2018

The aim of this study was to understand the roles of Sonic Hedgehog (SHH) signaling during tooth root and periodontium formation. In this study, we generated the dental mesenchyme-specific Smoothened (Smo) activated/inactivated mice with the activity of Cre recombinase under the control of osteocalcin promoter. In the Smo activated mutant molar sections at the postnatal 28 days, we found extremely thin root dentin and widened pulp chamber. Picrosirius red staining showed loosely arranged fibers in the periodontal space and decreased cellular cementum with some root resorption. Immunohistochemical staining showed less localization of matrix proteins such as Bsp, Dmp1, Pstn, and Ank in the cementum, periodontal ligament, and/or cementoblast. In the Smo inactivated mutant mouse, there was not any remarkable differences in the localization of these matrix proteins compared with the wild type. These findings suggest that adequate suppressing regulation of SHH signaling is required in the development of tooth root and periodontium.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2121-2127
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• 2012

Objective: Deoxyribonucleoside kinase of Drosophila melanogaster (Dm-dNK) mutants have been reported to exert suicide gene effects in combined gene/chemotherapy of cancer. Here, we aimed to further evaluate the capacity of the mutanted enzyme and its potential for inhibiting cancer cell growth. Methods: We altered the sequence of the last 10 amino acids of Dm-dNK to perform site-directed mutagenesis and constructed active site mutanted Dm-dNK (Dm-dNKmut), RT-PCR and western bloting studies were used to reveal the expression of lentivirus mediated Dm-dNKmut in a breast cancer cell line (Bcap37), a gastric cancer cell line (SGC7901) and a colorectal cancer cell line (CCL187). [3H]-labeled substrates were used for enzyme activity assays, cell cytotoxicity was assessed by MTT assays, cell proliferation using a hemocytometer and apoptosis induction by thenannexin-V-FITC labeled FACS method. In vivo, an animal study was set out in which BALB/C nude mice bearing tumors were treated with lentivirus mediated expression of Dm-dNKmut with the pyrimidine nucleoside analog brivudine (BVDU, (E)-5-(2-bromovinyl)-(2-deoxyuridine). Results: The Dm-dNKmut could be stably expressed in the cancer cell lines and retained its enzymatic activity. Moreover, the cells expressing Dm-dNKmut exhibited increased sensitivity in combination with BVDU, with induction of apoptosis in vitro and in vivo. Conclusion: These findings underlined the importance of BVDU phosphorylated by Dm-dNKmut in transduced cancer cells and the potential role of Dm-dNKmut as a suicide gene, thus providing the basis for future intensive research for cancer therapy.

• Archives of Pharmacal Research
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• v.29 no.10
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• pp.884-889
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• 2006

Mutation in the presenilin 2 (PS2mt) is known to be one of factors involved in the development of Alzheimer's disease (AD). It was recently revealed that an abnormality of lipid metabolism is a phenomenon occurring in AD. Therefore, the aim of this study was to investigate the potential relationship between the mutation of PS2 and alterations of the lipid profile within the brain. The results showed there increases in the levels of cholesterol, low density lipoprotein and triglyceride, but a decrease in the level of high density lipoprotein in brain tissues expressing mutant PS2. These findings indicated that PS2mt is involved in the abnormalities of the lipid profile, which could cause or result in the development of AD.

• Biomolecules & Therapeutics
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• v.26 no.3
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• pp.298-305
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• 2018

Rhomboid family member 2 gene (Rhbdf2) is an inactive homologue lacking essential catalytic residues of rhomboid intramembrane serine proteases. The protein is necessary for maturation of tumor necrosis factor-alpha ($TNF-{\alpha}$) converting enzyme, which is the molecule responsible for the release of $TNF-{\alpha}$. In this study, Rhbdf2 knockout (KO) mice were produced by CRISPR/CAS9. To see the effects of the failure of $TNF-{\alpha}$ release induced by Rhbdf2 gene KO, collagen-induced arthritis (CIA), which is the representative $TNF-{\alpha}$ related disease, was induced in the Rhbdf2 mutant mouse using chicken collagen type II. The severity of the CIA was measured by traditional clinical scores and histopathological analysis of hind limb joints. A rota-rod test and grip strength test were employed to evaluate the severity of CIA based on losses of physical functions. The results indicated that Rhbdf2 mutant mice showed clear alleviation of the clinical severity of CIA as demonstrated by the significantly lower severity indexes. Moreover, a grip strength test was shown to be useful for the evaluation of physical functional losses by CIA. Overall, the results showed that the Rhbdf2 gene has a significant effect on the induction of CIA, which is related to $TNF-{\alpha}$.

• Toxicological Research
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• v.20 no.1
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• pp.71-82
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• 2004

Changes in cell cycle control in the lungs and liver of the B6C3F1 mice (20 males per each group) exposed to ozone (0.5 ppm), 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK, 1.0 mg/kg), and dibutyl phthalate (DBP, 5,000 ppm) after 52 weeks were examined through Western, Northern blot, and immunohistochemistry based on alterations in protein expression levels of G1/S checkpoints (cyclin D1, cyclin E, and PCNA), G2/M checkpoints (cyclin B1, cyclin G, and cyclin A), negative regulators (p53, p21, GADD45, and p27), and positive regulator (mdm2). Expression levels of cyclins D1, E, G, PCNA, mutant p53, and mdm2 proteins were higher in the lungs and livers treated with combination of toxicants than in those treated with ozone only. Expression levels of the wild-type and mutant p53, p21, GADD45, p27, and mdm2 proteins and mRNAs were higher in toxicant-treated groups than those of the control. Immunohistochemical analysis revealed staining intensities of the PCNA, cyclin D1, c-myc and mdm2 protein- treated lungs and livers were stronger than those of the control group. Our results showed that combined treatment of ozone with NNK/DBP altered the cell cycle control through instability of the wild-type p53 gene. Such pivotal p53-mediated cell cycle alterations may be responsible for the toxicity observed under our experimental condition. These results may be applied to risk assessment of mixture-induced toxicity.

• Journal of Life Science
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• v.34 no.2
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• pp.79-85
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• 2024

SlyA is known as a transcriptional regulator that regulates the expression of hemolysin (HlyE) in E. coli, a member of the Enterobacteriaceae family such as Salmonella. However, Salmonella has the slyA gene but lacks the hlyE gene. Then, because we were curious about the role of SlyA in Salmonella, we constructed and explored a mutant strain with a deletion of the slyA gene. S. Typhimurium CK295 (ΔslyA) was constructed using an allelic exchange approach. In a comparative analysis between the wild-type and the CK295 strain, no significant differences were observed in growth characteristics, motility, total protein analyses, and secreted protein analyses. However, the CK295 strain exhibited slightly reduced biofilm formation compared to the wild-type. Interestingly, as a result of comparing the survival ability in macrophages, the mutant strain showed a 60% decrease in survival ability compared to the wild-type. To evaluate toxicity in mice, mortality was measured after oral administration to 6-week-old BALB/c mice. As a result, the LD₅₀ value of the CK295 (ΔslyA) was more than 100 times higher than that of wild-type S. Typhimurium 𝜒3339 in BALB/c. In conclusion, SlyA is presumed to regulate the expression of genes encoding virulence factors involved in the in vivo survival of Salmonella.

• Journal of Life Science
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• v.22 no.10
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• pp.1428-1433
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• 2012

Longevity is an exciting but difficult subject to study because it is determined by complex processes that require the coordinated action of several genetic factors as well as physiological and environmental influences. Genetic approaches have been applied to animal models to identify the molecular mechanism responsible for longevity. Several experimental model organisms obtained over the last decades suggest that the complete deletion of a single gene by gene targeting has proven to be an invaluable tool for the discovery of the mechanisms underlying longevity. The first discovery of long-lived mutants came from Caenorhabditis elegans research, which identified the insulin/IGF-1 pathway as responsible for longevity in this worm. IGF-1 is a multifunctional polypeptide that has sequence similarity to insulin and is involved in normal growth and development of cells. Several factors in the IGF-1 system have since been studied by gene targeting in the control of longevity in lower species, including nematode and fruit fly. In addition, significant progress has been made using mice models to extend the lifespan by targeted mutations that interfere with growth hormone/IGF-1 and IGF-1 signaling cascades. A recent finding that IGF-1 is involved in aging in mice was achieved by using liver-specific knockout mutant mice, and this clearly demonstrated that the IGF-1 signal pathway can extend the lifespan in both invertebrates and vertebrate models. Although the underlying molecular mechanisms for the control of longevity are not fully understood, it is widely accepted that reduced IGF-1 signaling plays an important role in the control of aging and longevity. Several genes involved in the IGF-1 signaling system are reviewed in relation to longevity in genetically modified mice models.

• Journal of Ginseng Research
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• v.37 no.1
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• pp.100-107
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• 2013

This study examined the effect of fermented ginseng (FG) on memory impairment and ${\beta}$-amyloid ($A{\beta}$) reduction in models of Alzheimer's disease (AD) in vitro and in vivo. FG extract was prepared by steaming and fermenting ginseng. In vitro assessment measured soluble $A{\beta}42$ levels in HeLa cells, which stably express the Swedish mutant form of amyloid precursor protein. After 8 h incubation with the FG extract, the level of soluble $A{\beta}42$ was reduced. For behavioral assessments, the passive avoidance test was used for the scopolamine-injected ICR mouse model, and the Morris water maze was used for a transgenic (TG) mouse model, which exhibits impaired memory function and increased $A{\beta}42$ level in the brain. FG extract was treated for 2 wk or 4 mo on ICR and TG mice, respectively. FG extract treatment resulted in a significant recovery of memory function in both animal models. Brain soluble $A{\beta}42$ levels measured from the cerebral cortex of TG mice were significantly reduced by the FG extract treatment. These findings suggest that FG extract can protect the brain from increased levels of $A{\beta}42$ protein, which results in enhanced behavioral memory function, thus, suggesting that FG extract may be an effective preventive or treatment for AD.

• BMB Reports
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• v.29 no.5
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• pp.468-473
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• 1996

The P38 promoter of minute virus of mice (MVM) is a very weak promoter which is strongly transactivated by viral nonstructural proteins. To analyze the upstream sequence of the P38 promoter which is responsible for the transactivation by nonstructural proteins in MVM, chloramphenicol acetyltransferase (CAT) reporter plasm ids containing a series of 5' deletion and internal deletion mutants of the P38 promoter were constructed. The wild type and mutant CAT constructs of P38 promoter were cotransfected into murine A92L fibroblast cells with a plasmid expressing viral nonstructural proteins by DEAE-dextran method. Each promoter activity was analyzed by CAT assay. As previously reported (Ahn et al., 1992), the proximal DNA cis-elements required for transactivation of the MVM P38 promoter are GC box and TATA box. However, the analysis of 5' deletion mutants showed that H-l tar like sequence (MVM TAR) which is located between -143 and -122 relative to the transcription initiation site is also required for transactivation of the P38 promoter by nonstructural proteins. Interestingly, even if the MVM TAR was removed by internal deletion, the level of the transactivation is still 70% of wild type level of transactivation. We also found that, in addition to the MVM TAR motif, there are two other motifs which are similar to the MVM TAR sequence. When these TAR like motifs were further deleted, the levels of transactivation were decreased further. Taken together, the MVM TAR sequence and TAR like motifs located upstream of P38 promoter are playing an important role for the transactivation of P38 promoter by nonstructural proteins in minute virus of mice.

• Journal of Ginseng Research
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• v.46 no.4
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• pp.572-584
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• 2022

Background: Huntington's disease (HD) is a neurodegenerative disorder caused by the expansion of trinucleotide CAG repeat in the Huntingtin (Htt) gene. The major pathogenic pathways underlying HD involve the impairment of cellular energy homeostasis and DNA damage in the brain. The protein kinase ataxia-telangiectasia mutated (ATM) is an important regulator of the DNA damage response. ATM is involved in the phosphorylation of AMP-activated protein kinase (AMPK), suggesting that AMPK plays a critical role in response to DNA damage. Herein, we demonstrated that expression of polyQ-expanded mutant Htt (mHtt) enhanced the phosphorylation of ATM. Ginsenoside is the main and most effective component of Panax ginseng. However, the protective effect of a ginsenoside (compound K, CK) in HD remains unclear and warrants further investigation. Methods: This study used the R6/2 transgenic mouse model of HD and performed behavioral tests, survival rate, histological analyses, and immunoblot assays. Results: The systematic administration of CK into R6/2 mice suppressed the activation of ATM/AMPK and reduced neuronal toxicity and mHTT aggregation. Most importantly, CK increased neuronal density and lifespan and improved motor dysfunction in R6/2 mice. Conversely, CK enhanced the expression of Bcl2 protected striatal cells from the toxicity induced by the overactivation of mHtt and AMPK. Conclusions: Thus, the oral administration of CK reduced the disease progression and markedly enhanced lifespan in the transgenic mouse model (R6/2) of HD.