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6. Tetrachloroaurate (III)–induced oxidation increases non-thermal plasma-induced oxidative stress

Author

Okazaki, Yasumasa, Sasaki, Kanako, Ito, Nanami, Tanaka, Hiromasa, Ken-ichiro, Matsumoto, Hori, Masaru, Toyokuni, Shinya, and Kenichiro, Matsumoto

Abstract

Non-thermal plasma (NTP) devices have been explored for medical applications. NTP devices discharge electrons, positive ions, ultraviolet and reactive oxygen species (ROS) and reactive nitrogen species (RNS), such as hydroxyl radical (●OH), singlet oxygen (1O2), superoxide (O2●-), hydrogen peroxide (H2O2), ozone and nitric oxide at near physiological temperature. In preclinical stages or human clinical trials, NTP promotes blood coagulation, eradication of bacterial, viral and biofilm-related infections, wound healing and cancer cell death. Here, we detected ferric, vanadium and gold(III) ions significantly elevated lipid peroxidation, which were measured by 2-thiobarbituric acid-reactive substances (TBARS) in combination with NTP exposure. Using 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (M4PO) as a spin probe, we identified tetrachloroaurate (III) yielded M4PO-X spin adduct with electron paramagnetic resonance (EPR). Tetrachloroaurate-induced oxidation was attenuated efficiently by reduced glutathione (GSH) and oxidized (GSSG), while glycine (Gly) and L-glutamate (Glu), which are constituent parts of GSH, were ineffective. Furthermore, GSH and GSSG efficiently suppressed tetrachloroaurate-induced lipid peroxidation, while Gly and Glu were also ineffective to suppress the elevation of TBARS. These results indicate that tetrachloroaurate-induced oxidation were attenuated by GSH as well as GSSG. Further studies were warranted to elucidate the redox reactions between metal ions and biomolecules that put forward the clinical application of NTP.

Published
2022

12. Extracellular stimulation of lung fibroblasts with arachidonic acid increases interleukin 11 expression through p38 and ERK signaling.

Author

Sasaki, Kanako, Komamura, Shotaro, and Matsuda, Kazuyuki

Subjects
*PROSTAGLANDIN receptors, *FIBROBLASTS, *ARACHIDONIC acid, *GENE expression, *FREE fatty acids, *CANCER cell motility, *CANCER cell proliferation
Abstract

Interleukin-11 (IL-11) is a pleiotropic cytokine that regulates proliferation and motility of cancer cells. Fibroblasts reside in the cancer microenvironment and are the primary source of IL-11. Activated fibroblasts, including cancer-associated fibroblasts that produce IL-11, contribute to the development and progression of cancer, and induce fibrosis associated with cancer. Changes in fatty acid composition or its metabolites, and an increase in free fatty acids have been observed in cancer. The effect of deregulated fatty acids on the development and progression of cancer is not fully understood yet. In the present study, we investigated the effects of fatty acids on mRNA expression and secretion of IL-11 in lung fibroblasts. Among the eight fatty acids added exogenously, arachidonic acid (AA) increased mRNA expression and secretion of IL-11 in lung fibroblasts in a dose-dependent manner. AA-induced upregulation of IL-11 was dependent on the activation of the p38 or ERK MAPK signaling pathways. Furthermore, prostaglandin E2, associated with elevated cyclooxygenase-2 expression, participated in the upregulation of IL-11 via its specific receptor in an autocrine/paracrine manner. These results suggest that AA may mediate IL-11 upregulation in lung fibroblasts in the cancer microenvironment, accompanied by unbalanced fatty acid composition. [ABSTRACT FROM AUTHOR]

Published
2023
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20. Effect of light exposure on linalool biosynthesis and accumulation in grape berries

Author

Sasaki, Kanako, Takase, Hideki, Matsuyama, Shuhei, Kobayashi, Hironori, Matsuo, Hironori, Ikoma, and Takata, Ryoji

Abstract

Linalool is an important compound that contributes to the floral aroma in wines. This study showed the effect of light exposure on linalool accumulation in berries. The grape bunches were covered with films that block the full light spectrum (Shade) and the UV spectrum (UV-block), and a transparent film (Control). The linalool content was significantly higher in juice from Control-covered berries than in juice from Shade- and UV-block-covered berries, and the expression levels of the representative genes in linalool biosynthesis in Shade- and UV-block-covered berries were markedly lower than in Control-covered berries. These findings suggest that exposing berries to light is essential for linalool biosynthesis. To reflect sunlight onto grape clusters, reflective sheets were placed on the ground of a vineyard. The linalool content in berries exposed to sunlight reflected from the reflective sheets was higher than those in the control. Effect of reflective sheets on linalool accumulation. (A) The grapes of Riesling (Vitis vinifera L.), (B) Linalool contents in grapes.

Published
2016
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28. Unique Solid-State Emission Behavior of Aromatic Difluoroboronated β-Diketones as an Emitter in Organic Light-Emitting Devices.

Author

Sasabe, Hisahiro, Sasaki, Kanako, Mamiya, Michitaka, Suwa, Yurie, Watanabe, Taiki, Onuma, Natsuki, Nakao, Kohei, Yamaji, Minoru, and Kido, Junji

Subjects
*SOLID state electronics, *KETONES, *ORGANIC light emitting diodes, *CARBAZOLE derivatives, *DELAYED fluorescence
Abstract

Aromatic difluoroboronated β-diketone ( BF2DK) derivatives are a widely known class of luminescent organic materials that exhibit high photoluminescent quantum efficiency and unique aggregation-dependent fluorescence behavior. However, there have been only a few reports on their use in solid-state electronic devices, such as organic light-emitting devices (OLEDs). Herein, we investigated the solid-state properties and OLED performance of a series of π-extended BF2DK derivatives that have previously been shown to exhibit intense fluorescence in the solution state. The BF2DK derivatives formed exciplexes with a carbazole derivative and exhibited thermally activated delayed fluorescence (TADF) behavior to give orange electroluminescence with a peak external quantum efficiency of 10 % that apparently exceeds the theoretical efficiency limit of conventional fluorescent OLEDs (7.5 %), assuming a light out-coupling factor of 30 %. [ABSTRACT FROM AUTHOR]

Published
2017
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31. Characterization of Coumarin-Specific Prenyltransferase Activities in Citrus limon Peel

Author

40790275, 20598601, 00191099, MUNAKATA, Ryosuke, INOUE, Tsuyoshi, KOEDUKA, Takao, SASAKI, Kanako, TSURUMARU, Yusuke, SUGIYAMA, Akifumi, UTO, Yoshihiro, HORI, Hitoshi, AZUMA, Jun-ichi, YAZAKI, Kazufumi, 40790275, 20598601, 00191099, MUNAKATA, Ryosuke, INOUE, Tsuyoshi, KOEDUKA, Takao, SASAKI, Kanako, TSURUMARU, Yusuke, SUGIYAMA, Akifumi, UTO, Yoshihiro, HORI, Hitoshi, AZUMA, Jun-ichi, and YAZAKI, Kazufumi

Abstract

Coumarins, a large group of polyphenols, play important roles in the defense mechanisms of plants, and they also exhibit various biological activities beneficial to human health, often enhanced by prenylation. Despite the high abundance of prenylated coumarins in citrus fruits, there has been no report on coumarin-specific prenyltransferase activity in citrus. In this study, we detected both O- and C-prenyltransferase activities of coumarin substrates in a microsome fraction prepared from lemon (Citrus limon) peel, where large amounts of prenylated coumarins accumulate. Bergaptol was the most preferred substrate out of various coumarin derivatives tested, and geranyl diphosphate (GPP) was accepted exclusively as prenyl donor substrate. Further enzymatic characterization of bergaptol 5-O-geranyltransferase activity revealed its unique properties: apparent Km values for GPP (9 µM) and bergaptol (140 µM) and a broad divalent cation requirement. These findings provide information towards the discovery of a yet unidentified coumarin-specific prenyltransferase gene.

Published
2012

33. Prenylation of aromatic compounds, a key diversification of plant secondary metabolites

Author

00191099, Yazaki, Kazufumi, Sasaki, Kanako, Tsurumaru, Yusuke, 00191099, Yazaki, Kazufumi, Sasaki, Kanako, and Tsurumaru, Yusuke

Abstract

Prenylation plays a major role in the diversification of aromatic natural products, such as phenylpropanoids, flavonoids, and coumarins. This biosynthetic reaction represents the crucial coupling process of the shikimate or polyketide pathway providing an aromatic moiety and the isoprenoid pathway derived from the mevalonate or methyl erythritol phosphate (MEP) pathway, which provides the prenyl (isoprenoid) chain. In particular, prenylation contributes strongly to the diversification of flavonoids, due to differences in the prenylation position on the aromatic rings, various lengths of prenyl chain, and further modifications of the prenyl moiety, e.g., cyclization and hydroxylation, resulting in the occurrence of ca. 1000 prenylated flavonoids in plants. Many prenylated flavonoids have been identified as active components in medicinal plants with biological activities, such as anti-cancer, anti-androgen, anti-leishmania, and anti-nitric oxide production. Due to their beneficial effects on human health, prenylated flavonoids are of particular interest as lead compounds for producing drugs and functional foods. However, the gene coding for prenyltransferases that catalyze the key step of flavonoid prenylation have remained unidentified for more than three decades, because of the membrane-bound nature of these enzymes. Recently, we have succeeded in identifying the first prenyltransferase gene SfN8DT-1 from Sophora flavescens, which is responsible for the prenylation of the flavonoid naringenin at the 8-position, and is specific for flavanones and dimethylallyl diphosphate (DMAPP) as substrates. Phylogenetic analysis showed that SfN8DT-1 has the same evolutionary origin as prenyltransferases for vitamin E and plastoquinone. A prenyltransferase GmG4DT from soybean, which is involved in the formation of glyceollin, was also identified recently. This enzyme was specific for pterocarpan as its aromatic substrate, and (-)-glycinol was the native substrate yielding the dire

Published
2009

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