• Journal of Life Science
• /
• v.30 no.6
• /
• pp.513-521
• /
• 2020

B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi1) is a polycomb group protein and a core component of polycomb repressive complex 1. Initial research into Bmi1 has focused on its role in tumorigenesis, and it is generally accepted that it is important for the proliferation and survival of cancer cells. However, more recent studies have revealed that Bmi1 is downregulated in brains with neurodegenerative disease and that it regulates the function of mitochondria and reactive oxygen species levels. In this study, we tested the therapeutic potential of Bmi1 in pilocarpine-induced seizures in Bmi1-knockout mice. Bmi1 expression transiently increased in the hippocampal CA1 and CA3 and the dentate gyrus following pilocarpine-induced status epilepticus (SE). In terms of seizure behavior, SE induction was 43.14% and 53.57% for Bmi1^+/+ and Bmi1^+/- mice, respectively. However, there was no significant difference in mortality or hippocampal damage between the two groups. Two months after SE induction, the frequency of epileptic seizures in the Bmi1^+/- mice was 50% lower than in the control group, although the difference was not statistically significant. In addition, mossy fiber outgrowth in the Bmi1^+/- mice was significantly higher than in their wild-type littermates. Taken together, these data indicate that reduced Bmi1 activity increases pilocarpine-induced seizure probability and mossy fiber outgrowth.

• Pediatric Infection and Vaccine
• /
• v.20 no.3
• /
• pp.123-130
• /
• 2013

Purpose: Subacute sclerosing panencephalitis (SSPE) is a neurodegerative disease due to persistent measles virus infection. We investigated the role of programmed death-1 (PD-1) molecule which is related with chronic viral infection in developing SSPE in mouse. Methods: We adopt the $PD-1^{-/-}$, $PD-1^{-/+}$, and wild type BALB/c 3 week old mice to make an animal model of SSPE by injecting measles virus (SSPE strain) intraventricularly. Three months after infusion of virus, the mice were sacrificed and examined if the typical pathologic lesions had been progressed. The sera were collected from each group of mice and the serum level of IL-21 was measured with ELISA kit. Results: The necrotic lesions on white matter and gliosis were found in focal areas in wild type BALB/c. The extent of lesion was smaller in heterotype BALB/c. Scanty lesions were found in $PD-1^{-/-}$ mice. The sera level of IL-21 was not elevated in all three groups. Conclusion: Our data suggest that the PD-1 molecule may play a role in persistent viral infection.

• Journal of Life Science
• /
• v.22 no.8
• /
• pp.1009-1017
• /
• 2012

The orf282 gene of Rhodobacter sphaeroides is located between the ccoNOQP operon encoding $cbb_3$ terminal oxidase and the fnrL gene encoding an anaerobic activator, FnrL. Its function remains unknown. In an attempt to reveal the function of the orf282 gene, we disrupted the gene by deleting a portion of the orf282 gene and constructed an orf282-knockout mutant. Two FnrL binding sites were found to be located upstream of orf282, and it was demonstrated that orf282 is positively regulated by FnrL. The orf282 gene is not involved in the regulation of spectral complex formation. The $cbb_3$ oxidase activity detected in the orf282 mutant was comparable to that in the wild-type sample, indicating that the orf282 gene is not involved in the regulation of the ccoNOQP operon and the biosynthesis of the cbb3 cytochrome c oxidase. The elevated promoter activity of the nifH and nifA genes, which are the structural genes of nitrogenase and its regulator, respectively, in the orf282 mutant, suggests that the orf282 gene product acts as a negative effector for nifH and nifA expression.

• Molecules and Cells
• /
• v.37 no.8
• /
• pp.605-612
• /
• 2014

The p73 gene contains an extrinsic P1 promoter and an intrinsic P2 promoter, controlling the transcription of the pro-apoptotic TAp73 isoform and the anti-apoptotic ${\Delta}Np73$ isoform, respectively. The DNA methylation status of both promoters act equally in the epigenetic transcriptional regulation of their relevant isoforms. The aim of this study was to analyze the different effects of these p73 isoforms in 5-aza-2'-deoxycytidine (5-aza-dC)-induced apoptosis in breast cancer cells. We investigated the effects of the DNA demethylation agent, 5-aza-dC, on the T-47D breast cancer cell line, and evaluated the methylation status of the p73 promoters and expression of TAp73 and ${\Delta}Np73$. Furthermore, we assessed the expression of p53 and p73 isoforms in 5-aza-dC-treated T-47D cells and p53 knockout cells. 5-aza-dC induced significant anti-tumor effects in T-47D cells, including inhibition of cell viability, G1 phase arrest and apoptosis. This was associated with p73 promoter demethylation and a concomitant increase in TAp73 mRNA and protein expression. In contrast, the methylation status of promoter P2 was not associated with ${\Delta}Np73$ mRNA or protein levels. Furthermore, demethylation of P2 failed to inhibit the expression of ${\Delta}Np73$ with 5-aza-dC in the p53 knockdown cell model. Our study suggests that demethylation of the P1 and P2 promoters has opposite effects on the expression of p73 isoforms, namely up-regulation of TAp73 and down-regulation of ${\Delta}Np73$. We also demonstrate that p53 likely contributes to 5-aza-dC-induced ${\Delta}Np73$ transcriptional inactivation in breast cancer cells.

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2008.05a
• /
• pp.23-25
• /
• 2008

Serum complement proteins comprise an important system that is responsible for several innate and adaptive immune defence mechanisms. There were three well described pathways known to lead to the generation of a C3 convertase, which catalyses the proteolysis of complement component C3, and leads to the formation of C3 opsonins (C3b, iC3b and C3d) that fix to bacteria. A pivotal step in the complement pathway is the assembly of a C3 convertase, which digests the C3 complement component to form microbial-binding C3 fragments recognized by leukocytes. The spleen clears microorganisms from the blood. Individuals lacking this organ are more susceptible to Streptococcus pneumoniae. Innate resistance to S. pneumoniae has previously been shown to involve complement components C3 and C4, however this resistance has only a partial requirement for mediators of these three pathways, such as immunoglobulin, factor B and mannose-binding lectin. Therefore it was likely that spleen and complement system provide resistance against blood-borne S. pneumoniae infection through unknown mechanism. To better understand the mechanisms involved, we studied Specific intracellular adhesion molecule-grabbing nonintegrin (SIGN)-R1. SIGN-R1, is a C-type lectin that is expressed at high levels by spleen marginal-zone macrophages and lymph-node macrophages. SIGN-R1 has previously been shown to be the main receptor for bacterial dextrans, as well as for the capsular pneumococcal polysaccharide (CPS) of S. pneumoniae. We examined the specific role of this receptor in the activation of complement. Using a monoclonal antibody that selectively downregulates SIGN-R1 expression in vivo, we show that in response to S. pneumoniae or CPS, SIGN-R1 mediates the immediate proteolysis of C3 and fixation of C3 opsonins to S. pneumoniae or to marginal-zone macrophages that had taken up CPS. These data indicate that SIGN-R1 is largely responsible for the rapid C3 convertase formation induced by S. pneumoniae in the spleen of mice. Also, we found that SIGN-R1 directly binds C1q and that C3 fixation by SIGN-R1 requires C1q and C4 but not factor B or immunoglobulin. Traditionally C3 convertase can be formed by the classical C1q- and immunoglobulin-dependent pathway, the alternative factor-B-dependent pathway and the soluble mannose-binding lectin pathway. Furthermore Conditional SIGN-R1 knockout mice developed deficits in C3 catabolism when given S. pneumoniae or its capsular polysaccharide intravenously. There were marked reductions in proteolysis of serum C3, deposition of C3 on organisms within SIGN-$R1^+$ spleen macrophages, and formation of C3 ligands. The transmembrane lectin SIGN-R1 therefore contributes to innate resistance by an unusual C3 activation pathway. We propose that in the SIGN-R1 mediated complement activation pathway, after binding to polysaccharide, SIGN-R1 captures C1q. SIGN-R1 can then, in association with several other complement proteins including C4, lead to the formation of a C3 convertase and fixation of C3. Therefore, this new pathway for C3 fixation by SIGN-R1, which is unusual as it is a classical C1q-dependent pathway that does not require immuno globulin, contributes to innate immune resistance to certain encapsulated microorganisms.

• Journal of Food Hygiene and Safety
• /
• v.31 no.4
• /
• pp.294-298
• /
• 2016

Natural products are attractive as the source of new drug development. Especially, numerous unknown marine bioresources are an object of attention because the ocean occupies three fourth of the earth. Survival of marine bioresources in extreme environment may induce the production of biological active compounds. As previous study, we examined over 40 specimens of marine sponges collected from Micronesia and screened their anti-proliferative activities in various cancer cell lines. Among them, we investigated Coscinoderma sp.'s activity and mechanism in human colon carcinoma HCT116 and RKO cells. Furthermore, we also used the p53-knockout of HCT116 cells and the p53 loss of RKO cells for elucidating the role of p53. Coscinoderma sp. inhibited cellular viability independently of the p53 status. Therefore, we compared the expression level of cell death-related proteins by Coscinoderma sp. in HCT16 and in HCT116 p53KO cells. Coscinoderma sp. increased p53 level and NOXA levels and induced apoptosis under the condition of p53 existence. On the other hand, Coscinoderma sp. increased p21 and mTOR levels in HCT116 p53KO cells. These results suggest that Coscinoderma sp. induced anti-proliferation effect through different pathway depending on p53 status.

• Journal of Life Science
• /
• v.21 no.11
• /
• pp.1636-1640
• /
• 2011

Alzheimer's disease (AD) is a progressive neurodegenerative disease, resulting in the loss of cognitive function. Mitochondrial aldehyde dehydrogenase (ALDH2) has been proposed to be a risk factor for the development of AD, but there is still controversy about that. In this study, we demonstrated the role of ALDH2 enzyme activity on amyloid-beta (A${\beta}$) and nuclear factor kappa B (NF-${\kappa}B$) expression in mice brain following ethanol exposure for 8 weeks. Five male Aldh2 (+/+) and Aldh2 (-/-) mice, 8 weeks-old of age (C57BL/6J strain), in each group were exposed to ethanol for 8 weeks (2 g/kg wt./day) using gavage. Those in the control groups received 0.9% saline alone. Results showed a difference in expression level of A${\beta}$ in the hippocampus after ethanol exposure according to the ALDH2 enzyme activity (p<0.05), but not in the level of NF-${\kappa}B$). Our results suggest a possibility that ALDH2 enzyme activity may be an important role in the development of AD.

• Journal of Periodontal and Implant Science
• /
• v.50 no.3
• /
• pp.159-170
• /
• 2020

Purpose: Immunization with Porphyromonas gingivalis heat shock protein 60 (PgHSP60) may have an immunoregulatory effect on atherogenesis. The aim of this study was to determine whether nasal immunization with a PgHSP60 peptide could reduce atherosclerotic plaque formation in apolipoprotein E knockout (ApoE KO) mice. Methods: Seven-week-old male ApoE KO mice were assigned to receive a normal diet, a Western diet, a Western diet and challenge with PgHSP60-derived peptide 14 (Pep14) or peptide 19 (Pep19), or a Western diet and immunization with Pep14 or Pep19 before challenge with Pep14 or Pep19. Results: Atherosclerotic plaques were significantly smaller in mice that received a Western diet with Pep14 nasal immunization than in mice that received a Western diet and no Pep14 immunization with or without Pep14 challenge. An immunoblot profile failed to detect serum reactivity to Pep14 in any of the study groups. Stimulation by either Pep14 or Pep19 strongly promoted the induction of CD4⁺CD25⁺ forkhead box P3 (FoxP3)⁺ human regulatory T cells (Tregs) in vitro. However, the expression of mouse splenic CD4⁺CD25⁺FoxP3⁺ Tregs was lower in the Pep14-immunized mice than in the Pep14-challenged or Pep19-immunized mice. Levels of serum interferon gamma (IFN-γ) and transforming growth factor beta were higher and levels of interleukin (IL) 10 were lower in the Pep14-immunized mice than in the other groups. Induction of CD25^- IL-17⁺ T helper 17 (Th17) cells was attenuated in the Pep14-immunized mice. Conclusions: Nasal immunization with Pep14 may be a mechanism for attenuating atherogenesis by promoting the secretion of IFN-γ and/or suppressing Th17-mediated immunity.

• Molecules and Cells
• /
• v.38 no.11
• /
• pp.998-1006
• /
• 2015

Retinols are metabolized into retinoic acids by alcohol dehydrogenase (ADH) and retinaldehyde dehydrogenase (Raldh). However, their roles have yet to be clarified in hepatitis despite enriched retinols in hepatic stellate cells (HSCs). Therefore, we investigated the effects of retinols on Concanavalin A (Con A)-mediated hepatitis. Con A was injected into wild type (WT), Raldh1 knockout ($Raldh1^{-/-}$), $CCL2^{-/-}$ and $CCR2^{-/-}$ mice. For migration study of regulatory T cells (Tregs), we used in vivo and ex vivo adoptive transfer systems. Blockade of retinol metabolism in mice given 4-methylpyrazole, an inhibitor of ADH, and ablated Raldh1 gene manifested increased migration of Tregs, eventually protected against Con A-mediated hepatitis by decreasing interferon-${\gamma}$ in T cells. Moreover, interferon-${\gamma}$ treatment increased the expression of ADH3 and Raldh1, but it suppressed that of CCL2 and IL-6 in HSCs. However, the expression of CCL2 and IL-6 was inversely increased upon the pharmacologic or genetic ablation of ADH3 and Raldh1 in HSCs. Indeed, IL-6 treatment increased CCR2 expression of Tregs. In migration assay, ablated CCR2 in Tregs showed reduced migration to HSCs. In adoptive transfer of Tregs in vivo and ex vivo, Raldh1-deficient mice showed more increased migration of Tregs than WT mice. Furthermore, inhibited retinol metabolism increased survival rate (75%) compared with that of the controls (25%) in Con A-induced hepatitis. These results suggest that blockade of retinol metabolism protects against acute liver injury by increased Treg migration, and it may represent a novel therapeutic strategy to control T cell-mediated acute hepatitis.

• The Korean Journal of Physiology and Pharmacology
• /
• v.19 no.5
• /
• pp.451-460
• /
• 2015

Sirtuin 1 (SIRT1) is a mammalian $NAD^+$-dependent protein deacetylase that regulates cellular metabolism and inflammatory response. The organ-specific deletion of SIRT1 induces local inflammation and insulin resistance in dietary and genetic obesity. Macrophage-mediated inflammation contributes to insulin resistance and metabolic syndrome, however, the macrophage-specific SIRT1 function in the context of obesity is largely unknown. C57/BL6 wild type (WT) or myeloid-specific SIRT1 knockout (KO) mice were fed a high-fat diet (HFD) or normal diet (ND) for 12 weeks. Metabolic parameters and markers of hepatic steatosis and inflammation in liver were compared in WT and KO mice. SIRT1 deletion enhanced HFD-induced changes on body and liver weight gain, and increased glucose and insulin resistance. In liver, SIRT1 deletion increased the acetylation, and enhanced HFD-induced nuclear translocation of nuclear factor kappa B (NF-${\kappa}B$), hepatic inflammation and macrophage infiltration. HFD-fed KO mice showed severe hepatic steatosis by activating lipogenic pathway through sterol regulatory element-binding protein 1 (SREBP-1), and hepatic fibrogenesis, as indicated by induction of connective tissue growth factor (CTGF), alpha-smooth muscle actin (${\alpha}$-SMA), and collagen secretion. Myeloid-specific deletion of SIRT1 stimulates obesity-induced inflammation and increases the risk of hepatic fibrosis. Targeted induction of macrophage SIRT1 may be a good therapy for alleviating inflammation-associated metabolic syndrome.