Kagoshima University · Graduate School of Medical and Dental Sciences · 助教

Research keywords漢方薬・DNA損傷・オキシトシン・メダカ・不安・恐怖条件付け・攻撃行動・種内変異・行動薬理学

Research fieldsDNA修復

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• Igarashi K, Kuchiiwa S, Kuchiiwa T, Tomita K, Sato T . Comparative data on emotional (psychotic) aggressive biting behavior in mice of ddY strain measured by using two devices; Aggressi2023 · 記述言語： 英語 DOI： 10.1016/j.dib.2023.109231 PubMed
• Yasuda T., Nakazawa T., Hirakawa K., Matsumoto I., Nagata K., Mori S., Igarashi K., Sagara H., Oda S., Mitani H. . Retinal regeneration after injury induced by gamma-ray irradiation during ear2023 · 記述言語： 英語 出版者・発行元： International Journal of Radiation Biology Purpose: Zebrafish, a small fish model, exhibits a multipotent ability for retinal regeneration after damage throughout its lifetime. Compared with zebrafish, birds and mammals exhibit such a regenerative capacity only during the embryonic period, and this capacity decreases with age. In medaka, another small fish model that has also been used extensively in biological research, the retina’s inner nuclear layer (INL) failed to regenerate after injury in the hatchling at eight days postfertilization (dpf). We characterized the regenerative process of the embryonic retina when the retinal injury occurred during the early embryonic period in medaka. Methods: We employed a 10 Gy dose of gamma-ray irradiation to initiate retinal injury in medaka embryos at 3 dpf and performed histopathological analyses up to 21 dpf. Results: One day after irradiation, numerous apoptotic neurons were observed in the INL; however, these neurons were rarely observed in the ciliary marginal zone and the photoreceptor layer. Numerous pyknotic cells were clustered in the irradiated retina until two days after irradiation. These disappeared four days after irradiation, but the abnormal bridging structures between the INL and ganglion cell layer (GCL) were present until 11 days after irradiation, and the neural layers were completely regenerated 18 days after irradiation. After gamma-ray irradiation, the spindle-like Müller glial cells in the INL became rounder but did not lose their ability to express SOX2. Conclusions: Irradiated retina at 3 dpf of medaka embryos could be completely regenerated at 18 days after irradiation (21 dpf), although the abnormal layer structures bridging the INL and GCL were transiently formed in the retinas of all the irradiated embryos. Four days after irradiation, embryonic medaka Müller glia were reduced in number but maintained SOX2 expression as in nonirradiated embryos. This finding contrasts with previous reports that 8 dpf medaka larvae could not fully regenerate damaged retinas because of loss of SOX2 expression. DOI： 10.1080/09553002.2023.2242932 Scopus PubMed
• Tomita K., Kuwahara Y., Igarashi K., Kitanaka J., Kitanaka N., Takashi Y., Tanaka K.i., Roudkenar M.H., Roushandeh A.M., Kurimasa A., Nishitani Y., Sato T. . Therapeutic potential for KCC2-tar2023 · 記述言語： 日本語 出版者・発行元： Japanese Dental Science Review Patients with neurological diseases, such as schizophrenia, tend to show low K+-Cl- co-transporter 2 (KCC2) levels in the brain. The cause of these diseases has been associated with stress and neuroinflammation. However, since the pathogenesis of these diseases is not yet fully investigated, drug therapy is still limited to symptomatic therapy. Targeting KCC2, which is mainly expressed in the brain, seems to be an appropriate approach in the treatment of these diseases. In this review, we aimed to discuss about stress and inflammation, KCC2 and Gamma-aminobutyric acid (GABA) function, diseases which decrease the KCC2 levels in the brain, factors that regulate KCC2 activity, and the possibility to overcome neuronal dysfunction targeting KCC2. We also aimed to discuss the relationships between neurological diseases and LPS caused by Porphyromonas gingivalis (P. g), which is a type of oral bacterium. Clinical trials on oxytocin, sirtuin 1 (SIRT1) activator, and transient receptor potential cation channel subfamily V Member 1 activator have been conducted to develop effective treatment methods. We believe that KCC2 modulators that regulate mitochondria, such as oxytocin, glycogen synthase kinase 3β (GSK3β), and SIRT1, can be potential targets for neurological diseases. DOI： 10.1016/j.jdsr.2023.11.001 Scopus PubMed
• Tomita K., Oohara Y., Igarashi K., Kitanaka J., Kitanaka N., Tanaka K.i., Roudkenar M.H., Roushandeh A.M., Sugimura M., Sato T. . Kamishoyosan and Kamikihito protect against decreased KCC2 exp2023 · 記述言語： 日本語 出版者・発行元： Heliyon Kamishoyosan (KSS) and Kamikihito (KKT) have been traditionally prescribed for neuropsychiatric symptoms in Japan. However, the molecular mechanism of its effect is not elucidated enough. On the other hand, it has been reported that lipopolysaccharide derived from Porphyromonas gingivalis (P. g LPS) is involved not only in periodontal disease but also in the systemic diseases such as psychiatric disorders via neuroinflammation. Here, we investigated the molecular mechanism of KSS and KKT treatment by LPS-induced neuropathy using PC-12 cells. When P. g LPS was administrated during the NGF treatment, the KCC2 expression was decreased in PC-12 cells. P. g LPS treatment also decreased the WNK and phospho SPAK (pSPAK) expression and enhanced GSK-3β expression that negatively regulates WNK-SPAK signaling. Moreover, when KSS or KKT was administrated before P. g LPS treatment, the decrease of KCC2, WNK and pSPAK was rescued. KSS and KKT treatment also rescued the enhancement of GSK3β expression by P. g LPS treatment. Furthermore, KSS, KKT and/or oxytocin could rescue behavioral abnormalities caused by P. g LPS treatment by animal experiments. These effects were not shown in the Goreisan treatment, which has been reported to act on the central nervous system. These results indicate that KSS and KKT are candidates for therapeutic agents for neural dysfunction. DOI： 10.1016/j.heliyon.2023.e22784 Scopus PubMed

• 放射線照射の惹起する認知機能障害からの回復を目的としたKCC2発現制御機序の解明2023 · 研究課題/領域番号： 23K16159 2023年4月 - 2026年3月
• 放射線治療後の脳機能低下を惹起しうるKCC2分子病態の解析1917 · 研究課題/領域番号： 19K19170 2019年4月 - 2023年3月
• ミトコンドリアを標的としたフェロトーシス誘導による治療抵抗性がん克服への挑戦
• 抗菌薬のドラッグ・リポジショニングを活用した放射線抵抗性がん克服への挑戦

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