• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.628-634
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• 2002

A microfilament-based motility in Toxoplasma gondii (T. gondii) Is involved in host cell invasion, yet the exact mechanism has not yet been determined. Accordingly, the current study examined the localization of actin and tubulin in T gondii using immunofluorescent (IF) and immunogold staining for electron microscopy. Indirect immunofluorescence (IF) staining using anti-actin and anti-tubulin monoclonal antibodies (mAbs) revealed localization of fluorescence on the entire surface of the tachyzoites. The actin in T. gondii was observed by immunogold staining, and the gold particles were seen on the surface, especially at the anterior end and in the cytoplasm of the parasite. However, there were no gold particles in the nucleus, rhoptries, and dense granules. The tubulin in T gondii was located on the surface and in the cytoplasm of the tachyzoites in the extracellular parasite, compared with anterior part of tachyzoites in the intracellular parasite. The antigens of T gondii recognized by anti-actin mAb were 107 kDa, 50 kDa, 48 kDa, and 40 kDa proteins, while those recognized by anti-tubulin mAb were 56 kDa, 52 kDa, and 34 kDa proteins. Tachyzoites of T gondii pretreated with the actin inhibitor, cytochalasin D (20 $\mu\textrm{g}$/ml), and tubulin inhibitor, colchicine (2$\times$10$\^$-6/ M), for 30 min at 37$\^{C}$ were used to infect the isolated mouse macrophages (tachyzo ites:macrophage=2:1). Pretreatment with the inhibitors resulted in lower multiplication of tachyzoites within the macrophages than in the untreated group 18 h post infection (p<0.05). Therefore, the present results suggest that actin and tubulin appear to be involved in the invasion of and multiplication in host cells.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3307-3312
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• 2014

The anti-inflammatory effect of a tubulin inhibitor, N-(5-benzyl-1,3-thiazol-2-yl)-3-(furan-2-yl)prop-2-enamide (1), on innate immune responses remains unclear. Thus, we investigated the effect of 1 on the immune responses mediated by lipopolysaccharide (LPS). The in vitro addition of 1 to dendritic cells and macrophages dose-dependently reduced tumor necrosis factor alpha production elicited by LPS stimulation. Additionally, the stimulation of natural killer (NK) and natural killer T (NKT) cells with 1 resulted in the decrease of interferon gamma ($IFN{\gamma}$) induced by LPS treatment. Moreover, 1 substantially reduced interleukin 12 in dendritic cells (DC) as well as $IFN{\gamma}$ in NKDCs induced by LPS in vitro. Furthermore, the in vivo administration of 1 ameliorated LPS/D-galactosamine-induced endotoxic lethality in mice. Taken together, our results demonstrate for the first time that 1 possesses anti-inflammatory properties, most notably by modulating LPS-induced innate immune responses. Therefore, 1 might have therapeutic potential for the treatment of inflammation-mediated diseases such as sepsis.

• Journal of Embryo Transfer
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• v.33 no.4
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• pp.229-235
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• 2018

Polo-like kinase 1 (Plk1) has been known to be a critical element in cell division including centrosome maturation, cytokinesis and spindle formation in somatic, cancer, and mammalian embryonic cells. In particular, Plk1 is highly expressed in cancer cells. Plk1 inhibitors, such as BI2536, have been widely used to prevent cell division as an anticancer drug. In this study, the fertilized murine oocytes were treated with BI2536 for 30 min after recovery from the oviduct to investigate the effect of down-regulation of Plk1 in the in vivo-fertilized murine embryos. Then, the localization and expression of Plk1 was observed by immunofluorescence staining. The sperm which had entered into the oocyte cytoplasm did not form male pronuclei in BI2536-treated oocytes. The BI2536-treated oocytes showed significantly lower expression of Plk1 than non-treated control group. In addition, alpha-tubulin and Plk1 gathered around sperm head in non-treated oocytes, while BI2536-treated oocytes did not show this phenomenon. The present study demonstrates that the Plk1 inhibitor, BI2536, hinders fertilization by inhibiting the formation of murine male pronucleus.

• BMB Reports
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• v.56 no.3
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• pp.178-183
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• 2023

Huntington's disease (HD) is a neurodegenerative disorder, of which pathogenesis is caused by a polyglutamine expansion in the amino-terminus of huntingtin gene that resulted in the aggregation of mutant HTT proteins. HD is characterized by progressive motor dysfunction, cognitive impairment and neuropsychiatric disturbances. Histone deacetylase 6 (HDAC6), a microtubule-associated deacetylase, has been shown to induce transport- and release-defect phenotypes in HD models, whilst treatment with HDAC6 inhibitors ameliorates the phenotypic effects of HD by increasing the levels of α-tubulin acetylation, as well as decreasing the accumulation of mutant huntingtin (mHTT) aggregates, suggesting HDAC6 inhibitor as a HD therapeutics. In this study, we employed in vitro neural stem cell (NSC) model and in vivo YAC128 transgenic (TG) mouse model of HD to test the effect of a novel HDAC6 selective inhibitor, CKD-504, developed by Chong Kun Dang (CKD Pharmaceutical Corp., Korea). We found that treatment of CKD-504 increased tubulin acetylation, microtubule stabilization, axonal transport, and the decrease of mutant huntingtin protein in vitro. From in vivo study, we observed CKD-504 improved the pathology of Huntington's disease: alleviated behavioral deficits, increased axonal transport and number of neurons, restored synaptic function in corticostriatal (CS) circuit, reduced mHTT accumulation, inflammation and tau hyperphosphorylation in YAC128 TG mouse model. These novel results highlight CKD-504 as a potential therapeutic strategy in HD.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3471-3476
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• 2012

Background and Objective: Histone deacetylase (HDAC) inhibitors represent a promising class of potential anticancer agents for treatment of human malignancies. In this study, we investigated the effect of trichostatin A (TSA), one such HDAC inhibitor, in combination with docetaxel (TXT), a cytotoxic chemotherapy agent or erlotinib, a novel molecular target therapy drug, on lung cancer A549 cells. Methods: A549 cells were treated with TXT, erlotinib alone or in combination with TSA, respectively. Cell viability, apoptosis, and cell cycle distribution were evaluated using MTT (3- (4, 5-dimethylthiazol-2-yl) -2, 5-diphenyltetrazolium bromide) assay, Hochst33258 staining and flow cytometry. Moreover, immunofluorescent staining and Western blot analysis were employed to examine alterations of ${\alpha}$-tubulin, heat shock protein 90 (hsp90), epidermal growth factor receptor (EGFR), and caspase-3 in response to the different exogenous stimuli. Results: Compared with single-agent treatment, co-treatment of A549 cells with TSA/TXT or TSA/erlotinib synergistically inhibited cell proliferation, induced apoptosis, and caused cell cycle delay at the $G_2/M$ transition. Treatment with TSA/TXT or TSA/erlotinib led to a significant increase of cleaved caspase-3 expression, also resulting in elevated acetylation of ${\alpha}$-tubulin or hsp90 and decreased expression of EGFR, which was negatively associated with the level of acetylated hsp90. Conclusions: Synergistic anti-tumor effects are observed between TXT or erlotinib and TSA on lung cancer cells. Such combinations may provide a more effective strategy for treating human lung cancer.

• Biomedical Science Letters
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• v.15 no.2
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• pp.141-146
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• 2009

Paclitaxel, an antimicrotubule agent, binds to beta-tubulin in the microtubule and stabilizes the polymer, thereby repressing dynamic instability. Here, we have demonstrated that microtubule cytoskeletal architecture involved in regulation of the COX-2 expression in chondrocyte treated with paclitaxel. Paclitaxel enhanced COX-2 expression and prostaglandin E2 production, as indicated by the Western blot analysis, reverse transcriptase PCR(RT-PCR) and immunofluorescence staining, and $PGE_2$ assay, respectively. In our previous data have shown that paclitaxel treatment stimulated activation of ERK-1/2 and p38 kinase(Im et al., 2009). SB203580, an inhibitor of p38 kinase, blocked the induction of COX-2 expression by paclitaxel. Also PD98059, an inhibitor of ERK-1/2 kinase was blocked the induced COX-2 expression. These results indicate that activation of ERK-1/2 and p38 kinase is required for COX-2 expression induced by paclitaxel in rabbit articular chondrocytes.

• Molecules and Cells
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• v.37 no.2
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• pp.126-132
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• 2014

As a tumor suppressor homologue during mitosis, Chk2 is involved in replication checkpoints, DNA repair, and cell cycle arrest, although its functions during mouse oocyte meiosis and early embryo development remain uncertain. We investigated the functions of Chk2 during mouse oocyte maturation and early embryo development. Chk2 exhibited a dynamic localization pattern; Chk2 expression was restricted to germinal vesicles at the germinal vesicle (GV) stage, was associated with centromeres at pro-metaphase I (Pro-MI), and localized to spindle poles at metaphase I (MI). Disrupting Chk2 activity resulted in cell cycle progression defects. First, inhibitor-treated oocytes were arrested at the GV stage and failed to undergo germinal vesicle breakdown (GVBD); this could be rescued after Chk2 inhibition release. Second, Chk2 inhibition after oocyte GVBD caused MI arrest. Third, the first cleavage of early embryo development was disrupted by Chk2 inhibition. Additionally, in inhibitor-treated oocytes, checkpoint protein Bub3 expression was consistently localized at centromeres at the MI stage, which indicated that the spindle assembly checkpoint (SAC) was activated. Moreover, disrupting Chk2 activity in oocytes caused severe chromosome misalignments and spindle disruption. In inhibitor-treated oocytes, centrosome protein ${\gamma}$-tubulin and Polo-like kinase 1 (Plk1) were dissociated from spindle poles. These results indicated that Chk2 regulated cell cycle progression and spindle assembly during mouse oocyte maturation and early embryo development.

• Archives of Pharmacal Research
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• v.25 no.2
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• pp.191-196
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• 2002

The water extract from the root bark of Cortex Mori (CM, Morus alba L.: Sangbaikpi), a mulberry tree, has been known in Chinese traditional medicine to have antiphlogistic, diuretic, and expectorant properties. In this study, the cytotoxicity of CM against tumor cells and its mechanism was examined . CM exhibited cytotoxic activity on K-562, B38O human leukemia cells and B16 mouse melanoma cells at concentrations of > 1 mg/ml. A DNA fragmentation, PARP cleavage, and nuclear condensation assay showed that those cells exposed to CM underwent apoptosis. The water extract of Scutellarie Radix (SR) was used as a negative control and showed no cytotoxicity in those cells. The flow cytometric profiles of the CM-treated cells were also indicative of apoptosis. However, they did not appear to exert the G1 arrest, which is observed in other tubulin inhibitor agents such as vincristine, taxol. The protein-binding test using Biacore and a microtubule assembly-disassembly assay provided evidence showing that CM bound to the tubulins resulting in 3 markets inhibition of the assembly, but not the disassembly of microtubules. The possible nonspecific effect of the CM extract could be excluded due to the results using SR, which did not affect the assembly process. Overall, the water extract of CM induces apoptosis of tumor cells by inhibiting microtubule assembly.

• Reproductive and Developmental Biology
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• v.29 no.3
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• pp.187-191
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• 2005

This study was designed to investigate the changes of quantity and quality of proteins in medium and cytoplasm during in vitro maturation of bovine oocytes. The total quantity of proteins in medium decreased from 0 to 4.5 hr, but increased from 13.5 to 18 hr after the onset of in vitro maturation. The total quantity of protein in cytoplasm increased from 0 to 4.5 hr, decreased from 4.5 to 9 hr, and increased after 18 hr after the onset of in vitro maturation. A total of 298 protein spots was detected on a gel of 2D SDS-PAGE form maturation medium. Among 28 protein spots expressed significant differences in their quantity, 8 proteins were identified by peptide mass fingerprinting (aldose reductase, alpha enolase, apolipoprotein A-1 precursor, 43kDa collectin precursor, heat shock 27kDa protein, plasminogen activator inhibitor-1 precursor, thrombospondin 1, transitional endoplasmic reticulum ATPase). Among total of 35 protein spots detected on gel of 2D SDS-PACE from oorytes cytoplasm, $\beta$-tubulin was identified by peptide mass fingerprinting.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.228-231
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• 2009

We have purified Phytophthora capsici alpha and beta tubulin from Escherchia coli BL21(DE3). The recombinant alpha and beta tubulins were assembled into microtubule in vitro with specific conditions. The metagenome library was isolated from soil in the Mt. Yeo-Ki, Suwon, Korea and manufactured with the method mentioned in experiment contents for in vitro screening of microtubule assembly screening. FRET effect was used for microtubule assembly inhibitor screening with metagenome library. We got 2 metagenome clones from in vitro screening, and these 2 hit clones showed P. capsici growth inhibition activity on the growing pepper plants. These results suggest that new development of potent inhibitor for pepper blight disease and new approach to prevention of pepper blight disease.