• Parasites, Hosts and Diseases
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• v.62 no.3
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• pp.281-293
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• 2024

We previously reported that leukotriene B₄ (LTB₄) contained in Trichomonas vaginalis-derived secretory products (TvSP) play an essential role in interleukin-8 (IL-8) production in human mast cell line (HMC-1 cells) via LTB₄ receptor (BLT)-mediated Nuclear Factor-kappa B (NF-κB) activation. Dynamin, a GTPase, has been known to be involved in endocytosis of receptors for signaling of production of cytokine or chemokines. In the present study, we investigated the role of dynamin-mediated BLT1 endocytosis in TvSP-induced IL-8 production. When HMC-1 cells were transfected with BLT1 or BLT2 siRNA, TvSP-induced IL-8 production was significantly inhibited compared with that in cells transfected with control siRNA. In addition, pretreatment of HMC-1 cells with a dynamin inhibitor (Dynasore) reduced IL-8 production induced by TvSP or LTB₄. TvSP- or LTB₄-induced phosphorylation of NF-κB was also attenuated by pretreatment with Dynasore. After exposing HMC-1 cells to TvSP or LTB₄, BLT1 was translocated from the intracellular compartments to the plasma membrane within 30 min. At 60 min after stimulation with TvSP or LTB₄, BLT1 remigrated from the cell surface to intracellular areas. Pretreatment of HMC-1 cells with dynamin-2 siRNA blocked internalization of BLT1 induced by TvSP or LTB₄. Co-immunoprecipitation experiments revealed that dynamin-2 strongly interacted with BLT1 60 min after stimulation with TvSP or LTB₄. These results suggest that T. vaginalis-secreted LTB₄ induces IL-8 production in HMC-1 cells via dynamin 2-mediated endocytosis of BLT1 and phosphorylation of NF-κB.

• BMB Reports
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• v.51 no.8
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• pp.373-377
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• 2018

Triple-negative breast cancer (TNBC) is considered to be a notorious type of cancer due to its aggressive metastatic potential and poor prognosis. Recent evidence suggests that BLT2, a low-affinity $LTB_4$ receptor is critically associated with the phenotypes of TNBC cells, including invasion, metastasis, and survival. Furthermore, in a group of 545 breast cancer patients with metastasis, we observed that the high-BLT2 subgroup had a lower disease-free-survival rate than the low-BLT2 subgroup. Thus, we theorized that anti-BLT2 strategies could facilitate the development of new therapies used for TNBC. This review focuses on recent discoveries regarding BLT2 and its roles in as a novel prognostic biomarker in TNBC.

• BMB Reports
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• v.49 no.4
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• pp.232-237
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• 2016

Mulberry tree twigs (Ramulus mori) contain large amounts of oxyresveratrols and have traditionally been used as herbal medicines because of their anti-inflammatory properties. However, the signaling mechanism by which R. mori exerts its anti-inflammatory action remains to be elucidated. In this study, we observed that R. mori ethanol extracts (RME) exerted an inhibitory effect on the lipopolysaccharide (LPS)-induced production of the pro-inflammatory cytokine interleukin-6 (IL-6) in Raw264.7 macrophage cells. Additionally, RME inhibited IL-6 production by blocking the leukotriene B₄ receptor-2 (BLT2)-dependent-NADPH oxidase 1 (NOX1)-reactive oxygen species (ROS) cascade, leading to anti-inflammatory activity. Finally, RME suppressed the production of the BLT2 ligands LTB4 and 12(S)-HETE by inhibiting the p38 kinase-cytosolic phospholipase A₂-5-/12-lipoxygenase cascade in LPS-stimulated Raw264.7 cells. Overall, our results suggest that RME inhibits the 'BLT2 ligand-BLT2'-linked autocrine inflammatory axis, and that this BLT2-linked cascade is one of the targets of the anti-inflammatory action of R. mori.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.4
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• pp.265-271
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• 2003

Ferroelectric lanthanum-substituted Bi$_4$Ti$_3$O$_{12}$(BLT) thin films were fabricated by spin-coating onto a Pt/Ti/SiO$_2$/Si substrate by metalorganic decomposition technique. The grain size in BLT thin films were prepared with controlled by various drying process. The effect of grain size on the crystallization and ferroelectric properties were investigated by x-ray diffraction and field emission scanning electron microscope. The dependence of crystallization and electrical properties are related to the grain size in BLT thin films with different drying temperature. The remanent polarization of BLT thin film increases with the increasing grain size. The value of 2P$_{r}$ and E$_{c}$ of BLT thin film dried at 45$0^{\circ}C$ were 25.9 $\mu$C/$\textrm{cm}^2$ and 85 kV/cm, respectively. The BLT thin film with larger grain size has better fatigue properties. The fatigue properties revealed that small grained film showed more degradation of switching charge than large grained films.lms.s.

• Molecules and Cells
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• v.27 no.4
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• pp.403-408
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• 2009

Skeletal muscle regeneration is a highly orchestrated process initiated by activation of adult muscle satellite cells. Upon muscle injury, the inflammatory process is always accompanied by muscle regeneration. Leukotriene $B_4$ is one of the essential inflammatory mediators. We isolated and cultured primary satellite cells. RT-PCR showed that myoblasts expressed mRNA for $LTB_4$ receptors BLT1 and BLT2, and $LTB_4$ promoted myoblast proliferation and fusion. Quantitative real-time PCR and immunoblotting showed that $LTB_4$ treatment expedited the expression process of differentiation markers MyoD and M-cadherin. U-75302, a specific BLT1 inhibitor, but not LY2552833, a specific BLT2 inhibitor, blocked proliferation and differentiation of myoblasts induced by $LTB_4$, which implies the involvement of the BLT1 pathway. Overall, the data suggest that $LTB_4$ contributes to muscle regeneration by accelerating proliferation and differentiation of satellite cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.186-189
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• 2002

The MFIS capacitors were fabricated using a metalorganic decomposition method. Thin layers of $CeO_2$ were deposited as a buffer layer on Si substrate and BLT thin films were used as a ferroelectric layer. The electrical and structural properties of the MFIS structure were investigated. X-ray diffraction was used to determine the phase of the BLT thin films and the quality of the $CeO_2$ layer. The morphology of films and the interface structures of the BLT and the $CeO_2$ layers were investigated by scanning electron microscopy. The width of the memory window in the C-V curves for the MFIS structure is 4.78 V. The experimental results show that the BLT-based MFIS structure is suitable for non-volatile memory FETs with large memory window.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.486-491
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• 2002

We have fabricated $Bi_{3.25}La_{0.75}Ti_3O_12$ (BLT) thin films on the Pt/Ti/$SiO_2$/Si substrates using a metalorganic decomposition (MOD) method with annealing temperature from $550^{\circ}C$ to $750^{\circ}C$. The structural properties of BLT films examined by x-ray diffraction (XRD). From XRD analysis. BLT thin films show polycrystalline structure. The layered-perovskite phase was obtained by spin-on films at above $600^{\circ}C$ for 1h. Scanning electron microscopy (SEM) showed uniform surface composed of rodlike grains. The grain size of BLT films increased with increasing annealing temperature. The BLT film annealed at $650^{\circ}C$ was measured to have a dielectric constant of 279, dielectric loss of 1.85(%), remanent polarization of $25.66\mu C/\textrm{cm}^2$, and coercive field of 84.75 kV/cm. The BLT thin films showed little polarization fatigue test up to $3.5{\times}10^9$ bipolar cycling at 5 V and 100 kHz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.305-309
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• 2002

We have successfully fabricated a Metal-Ferroelectric-Insulator-Semiconductor (MFIS) structure using Bi$\sub$4-x/La$\sub$x/Ti$_3$O$\sub$12/ (BLT) ferroelectric thin film and SiO$_2$/Nitride/SiO$_2$ (ONO) stacked buffer layers for single transistor type ferroelectric nonvolatile memory applications. BLT films were deposited on 15 nm-thick ONO buffer layer by sol-gel spin-coating. The dielectric constant and the leakage current density of prepared ONO film were measured to be 5.6 and 1.0 x 10$\^$-8/ A/$\textrm{cm}^2$ at 2MV/cm, respectively, It was interesting to note that the crystallographic orientations of BLT thin films were strongly effected by pre-bake temperatures. X-ray diffraction patterns showed that (117) crystallites were mainly detected in the BLT film if pre-baked below 400$^{\circ}C$. Whereas, for the films pre-baked above 500$^{\circ}C$, the crystallites with preferred c-axis orientation were mainly detected. From the C-V measurement of the MFIS capacitor with c-axis oriented BLT films, the memory window of 0.6 V was obtained at a voltage sweep of ${\pm}$8 V, which evidently reflects the ferroelectric memory effect of a BLT/ONO/Si structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.172-173
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• 2006

Metal-ferroelectric-insulator-semiconductor (MFIS) structures with $Bi_{3.35}La_{0.75}Ti_3O_{12}$ (BLT) ferroelectric film and Zirconium oxide ($ZrO_2$) layer were fabricated on p-type Si(100). $ZrO_2$ and BLT films were prepared by sol-gel technique. Surface morphologies of $ZrO_2$ and BLT film were measured by atomic force microscope (AFM). The electrical characteristics of Au/$ZrO_2$/Si and Au/BLT/$ZrO_2$/Si film were investigated by C-V and I-V measurements. No hysteretic characteristics was observed in the C-V curve of the Au/$ZrO_2$/Si structure. The memory window width m C-V curve of the Au/BLT/$ZrO_2$/Si diode was about 1.3 V for a voltage sweep of ${\pm}5$ V. The leakage current of Au/$ZrO_2$/Si and Au/BLT/$ZrO_2$/Si structures were about $3{\times}10^{-8}$ A at 30 MV/cm and $3{\times}10^{-8}$ A at 3 MV/cm, respectively.

• Journal of the Korean Ceramic Society
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• v.43 no.4 s.287
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• pp.220-223
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• 2006

BLT nanotubes were synthesized by using simple and convenient method template-wetting process. Porous alumina membranes were prepared by 2 step anodic oxidation as the template. To improve wetting properties and make low surface energy, BLT solution was mixed with polymer. Polymer was removed completely during annealing. After completely etching the template in 30 wt% KOH solution, we demonstrate that BLT nanotubes with a diameter of 200 nm can be fabricated. Grain growth process of BLT nanotubes during baking, and furnace annealing was examined by FE-SEM and XRD.