研究者詳細 - 豊國　伸哉

論文 - 豊國　伸哉

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芳香族アミン類MOCAのDNA酸化損傷に関する研究－ラット肝臓における8 -ヒドロキシ-2’-デオキシグアノシンの検討－国際誌

小林沙穂, 本岡大社, 柏木裕呂樹, 豊國伸哉

労働安全衛生研究 16 巻 ( 1 ) 頁： 45 - 49 2023年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：独立行政法人労働者健康安全機構労働安全衛生総合研究所

芳香族アミン類の一種である3,3’-ジクロロ-4,4’-ジアミノジフェニルメタン（MOCA）は，ウレタン樹脂の硬化剤等に産業利用される一方，国際がん研究機関によりグループ1（ヒトに発がん性あり）に分類され，労働者の健康影響が懸念されている．MOCAの発がん過程には，肝臓をはじめとした各臓器で代謝される際に生じる活性酸素種（ROS）やDNA付加体によるDNA損傷が関係すると考えられているが，その中でもROSによって引き起こされるDNA酸化的損傷である8-ヒドロキシ-2’ -デオキシグアノシン（8-オキソグアニン：8-OHdG）は，高頻度に発生し，DNA複製時のG→Tの点突然変異を惹起する．しかし，実験動物においてMOCAばく露が実際に変異原性の高い8-OHdGを引き起こすか調べた研究は我々の知る限り存在しない． そこで本研究では，ラットを用い，肝臓におけるMOCAばく露が十分に期待できる経口投与法により，0（対照）, 0.4, 2, 10, 50mg/kg/日の用量で週3回2週間の反復ばく露を実施し，その標的臓器である肝臓について，病理解析及び8-OHdGの生成レベルを検討した．その結果，病理所見では，50mg/kg/日投与群において空胞変性が認められた一方， 8-OHdGは，0.4mg/kg/日投与群を除いて用量依存的な若干の増加傾向がみられたが，いずれも有意な差は認められなかった．以上から，少なくとも8-OHdGはMOCAにより引き起こされる発がんメカニズムの主原因ではないと推察される．

DOI： 10.2486/josh.josh-2022-0022-ta

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Cancer-specific cytotoxicity of Ringer's acetate solution irradiated by cold atmospheric pressure plasma. 査読有り国際誌 Open Access

Miron C, Ishikawa K, Kashiwagura S, Suda Y, Tanaka H, Nakamura K, Kajiyama H, Toyokuni S, Mizuno M, Hori M

Free radical research 57 巻 ( 2 ) 頁： 91 - 104 2023年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Free Radical Research

Cold atmospheric pressure plasmas are promising medical tools that can assist in cancer treatment. While the medical pathology mechanism is substantially understood, knowledge of the contribution of reactive species formed in plasma and the mode of activation of biochemical pathways is insufficient. Herein, we present a concept involving antitumoral plasma-activated organics, which is envisaged to increase cytotoxicity levels against cancer cells. Ringer′s acetate solution was irradiated by low-temperature plasma at atmospheric pressure and possible reaction pathways of the compound generation are presented. The chemical compounds formed by plasma treatment and their effects on non-tumorigenic breast epithelial cells (MCF-10A) and breast cancer cells (MCF-7) were investigated. The cell viability results have shown that plasma-derived compounds have both, stimulatory and inhibitory effects on cell viability, depending on the concentration of the generated compounds in the irradiated liquids. Previous studies have shown that oxidative stresses involving reactive oxygen and nitrogen species (RONS) can be used to kill cancer cells. Hence, while RONS offers promising first-step killing effects, cell viability results have shown that plasma-derived compounds, such as acetic anhydride and ethyl acetate, have the potential to play important roles in plasma-based cancer therapy.

DOI： 10.1080/10715762.2023.2201390

Environmental impact on carcinogenesis under BRCA1 haploinsufficiency. 査読有り国際誌 Open Access

Toyokuni S, Kong Y, Motooka Y, Akatsuka S

Genes and environment : the official journal of the Japanese Environmental Mutagen Society 45 巻 ( 1 ) 頁： 2 - 2 2023年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Genes and Environment

Cancer is the primary cause of human mortality in Japan since 1981. Although numerous novel therapies have been developed and applied in clinics, the number of deaths from cancer is still increasing worldwide. It is time to consider the strategy of cancer prevention more seriously. Here we propose a hypothesis that cancer can be side effects of long time-use of iron and oxygen and that carcinogenesis is an evolution-like cellular events to obtain “iron addiction with ferroptosis-resistance” where genes and environment interact each other. Among the recognized genetic risk factors for carcinogenesis, we here focus on BRCA1 tumor suppressor gene and how environmental factors, including daily life exposure and diets, may impact toward carcinogenesis under BRCA1 haploinsufficiency. Although mice models of BRCA1 mutants have not been successful for decades in generating phenotype mimicking the human counterparts, a rat model of BRCA1 mutant was recently established that reasonably mimics the human phenotype. Two distinct categories of oxidative stress, one by radiation and one by iron-catalyzed Fenton reaction, promoted carcinogenesis in Brca1 rat mutants. Furthermore, mitochondrial damage followed by alteration of iron metabolism finally resulted in ferroptosis-resistance of target cells in carcinogenesis. These suggest a possibility that cancer prevention by active pharmacological intervention may be possible for BRCA1 mutants to increase the quality of their life rather than preventive mastectomy and/or oophorectomy.

DOI： 10.1186/s41021-023-00258-5

Exposure of low-temperature plasma after vaccination in tongue promotes systemic IgM induction against spike protein of SARS-CoV-2. 査読有り国際誌 Open Access

Sato K, Fujii K, Tanaka H, Hori M, Hibi H, Toyokuni S

Free radical research 57 巻 ( 1 ) 頁： 30 - 37 2023年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Free Radical Research

COVID-19 has been pandemic since 2020 with persistent generation of new variants. Cellular receptor for SARS-CoV-2 is angiotensin-converting enzyme 2 (ACE2), where transmembrane serine protease-2 (TMPRSS2) is essential for viral internalization. We recently reported abundant expression of ACE2 and TMPRSS2 in the oral cavity of humans and mice. Therefore, oral cavity may work for COVID-19 infection gates. Here we undertook to evaluate whether vaccination in the tongue harbors any merit in comparison to subcutaneous injection. Low-temperature plasma (LTP) is the fourth physical state of matters with ionization above gas but at body temperature. LTP provides complex chemistry, eventually supplying oxidative and/or nitrosative stress on the interface. LTP-associated cellular death has been reported to cause apoptosis and/or ferroptosis. However, there is few data available on immunogenicity retention after LTP exposure. We therefore studied the effect of LTP exposure after the injection of keyhole limpet hemocyanin (KLH) or spike 2 protein of SARS-CoV-2 to the tongue of six-week-old male BALB/c mice, compared to subcutaneous vaccination. Whereas LTP did not change the expression of ACE2 and TMPRSS2 in the tongue, repeated LTP exposure after tongue vaccination significantly promoted systemic and specific IgM production at day 11. In contrast, repeated LTP exposure after subcutaneous vaccination of KLH decreased systemic IgM production. Of note, tongue injection produced significantly higher titer of IgM and IgG in the case of KLH. In conclusion, LTP significantly reinforced humoral immunity by IgM after tongue injection. Vaccination to the tongue can be a novel strategy to acquire immediate immunity.

DOI： 10.1080/10715762.2023.2190486

Low-temperature plasma as magic wand to differentiate between the good and the evil. 査読有り国際誌 Open Access

Toyokuni S, Zheng H, Kong Y, Sato K, Nakamura K, Tanaka H, Okazaki Y

Free radical research 57 巻 ( 1 ) 頁： 38 - 46 2023年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Free Radical Research

Plasma is the fourth physical state of matter, characterized by an ionized gaseous mixture, after solid, liquid, and gas phases, and contains a wide array of components such as ions, electrons, radicals, and ultraviolet ray. Whereas the sun and thunder are typical natural plasma, recent progress in the electronics enabled the generation of body-temperature plasma, designated as low-temperature plasma (LTP) or non-thermal plasma since the 1990s. LTP has attracted the attention of researchers for possible biological and medical applications. All the living species on earth utilize water as essential media for solvents and molecular transport. Thus, biological application of LTP naturally intervenes water whether LTP is exposed directly or indirectly, where plasma-activated lactate (PAL) is a standard, containing H<inf>2</inf>O<inf>2</inf>, NO<inf>2</inf>− and other identified molecules. Electron spin resonance and immunohistochemical studies demonstrated that LTP exposure is a handy method to load local oxidative stress. Cancer cells are characterized by persistent self-replication and high cytosolic catalytic Fe(II). Therefore, both direct exposure of LTP and PAL can provide higher damage to cancer cells in comparison to non-tumorous cells, which has been demonstrated in a variety of cancer types. The cell death mode is either apoptosis or ferroptosis, depending on the cancer-type. Thus, LTP and PAL are expected to work as an additional cancer therapy to the established guideline protocols, especially for use in somatic cavities or surgical margins.

DOI： 10.1080/10715762.2023.2190860

Extracellular fine particles and carcinogenesis 査読有り国際誌

Toyokuni S.

Seikagaku 95 巻 ( 2 ) 頁： 177 - 183 2023年

担当区分：最終著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Seikagaku

外因性微粒子や感染に伴う炎症反応は体内の鉄分布を大きく変え，細胞外の鉄を減らすように作用するため，細胞内鉄過剰が発生する．過剰鉄は発がんリスクである．鉄は細胞増殖に必須な酵素の補因子であるが，過剰鉄はフェントン反応により変異性DNA傷害を起こし，発がんの基盤となるフェロトーシス抵抗性を持った細胞の進化・選択を促進する．血清フェリチン値は体内鉄貯蔵の指標だがその分泌機構は不明であった．我々は最近，ヒト細胞において細胞外小胞（EV）のマーカーCD63が鉄代謝に固有なIRP/IREを介して転写後制御を受け，鉄が十分あるときには鉄充填フェリチンをEVとして分泌することを明らかにした．一方，アスベストに曝露されたマクロファージはフェロトーシスに陥るが，そのとき同様の鉄充填フェリチンをEVとして放出し，それを受け取った中皮細胞に変異性傷害を与えることを見いだした．

DOI： 10.14952/SEIKAGAKU.2023.950177

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Thioredoxin deficiency increases oxidative stress and causes bilateral symmetrical degeneration in rat midbrain. 査読有り国際誌 Open Access

Ohmori I, Ouchida M, Imai H, Ishida S, Toyokuni S, Mashimo T

Neurobiology of disease 175 巻頁： 105921 - 105921 2022年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Neurobiology of Disease

Thioredoxin, encoded by Txn1, acts as a critical antioxidant in the defense against oxidative stress by regulating the dithiol/disulfide balance of interacting proteins. The role of thioredoxin in the central nervous system (CNS) is largely unknown. A phenotype-driven study of N-ethyl-N-nitrosourea-mutated rats with wild-running seizures revealed the importance of Txn1 mutations in CNS degeneration. Genetic mapping identified Txn1-F54L in the epileptic rats. The insulin-reducing activity of Txn1-F54L was approximately one-third of that of the wild-type (WT). Bilateral symmetrical vacuolar degeneration in the midbrain, mainly in the thalamus and the inferior colliculus, was observed in the Txn1-F54L rats. The lesions displayed neuronal and oligodendrocytic cell death. Neurons in Txn1-F54L rats showed morphological changes in the mitochondria. Vacuolar degeneration peaked at five weeks of age, and spontaneous repair began at seven weeks. The TUNEL assay showed that fibroblasts derived from homozygotes were susceptible to cell death under oxidative stress. In five-week-old WT rats, energy metabolism in the thalamus was significantly higher than that in the cerebral cortex. In conclusion, in juvenile rats, Txn1 seems to play an essential role in reducing oxidative stress in the midbrains with high energy metabolism.

DOI： 10.1016/j.nbd.2022.105921

RhoA and vigilin are candidates for immunohistochemical markers for epithelioid malignant mesothelioma. 国際誌 Open Access

Hiratsuka T, Yamamoto T, Yoshizawa A, Toyokuni S, Tsuruyama T

Scientific reports 12 巻 ( 1 ) 頁： 18519 2022年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Scientific Reports

Diagnostic markers of malignant mesothelioma (MM) have been extensively investigated. Immunohistochemistry (IHC) markers, such as calretinin, have been used for pathologic diagnosis. However, more diagnostic markers are required to improve the specificity and sensitivity of pathologic diagnosis. This study proposed two proteins as diagnostic markers for epithelioid MM. One is RhoA, an MM mutation-susceptible locus-derived protein, and another is vigilin, a lung small cell carcinoma marker. IHC was performed using 93 MM (epithelioid, 71 cases; sarcomatoid, 13 cases; and biphasic, 9 cases), 64 lung adenocarcinoma (LAC), 60 lung squamous cell carcinoma (LSC), and 14 normal mesothelial (NM) tissues. The majority of epithelioid MM cases were positive for both RhoA and vigilin, whereas both IHCs showed lower stainability in biphasic and sarcomatoid MM. Besides, both IHCs showed significantly higher stainability for RhoA and vigilin in epithelioid MM than in LAC and LSC (p < 0.05). Chi-square tests showed that both RhoA and vigilin IHC positive rate in epithelioid MM was not significantly different from that of calretinin (p > 0.05). In the differential diagnosis of MM from lung cancer, the accuracy and specificity of RhoA, vigilin, and calretinin staining were almost equivalent. Further, H-score test showed that there was no significant difference between RhoA versus calretinin and vigilin versus calretinin in IHC positivity in epithelioid MM (p > 0.05). In conclusion, RhoA and vigilin may be candidates for immunohistochemical markers for epithelioid MM.

DOI： 10.1038/s41598-022-20334-0

Molecular hydrogen has a positive impact on pregnancy maintenance through enhancement of mitochondrial function and immunomodulatory effects on T cells. 査読有り国際誌

Aoki C, Imai K, Mizutani T, Sugiyama D, Miki R, Koya Y, Kobayashi T, Ushida T, Iitani Y, Nakamura N, Owaki T, Nishikawa H, Toyokuni S, Kajiyama H, Kotani T

Life sciences 308 巻頁： 120955 - 120955 2022年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Life Sciences

Aims: Molecular hydrogen (H<inf>2</inf>) has attracted growing interest because of its implications in various diseases. However, the molecular mechanisms underlying the remarkable effect of a small amount of H<inf>2</inf> remain elusive. No knowledge has been available on the role of H<inf>2</inf> in the etiology of pregnancy disorders or its direct influence on human immune cells. Since maternal immunity, T cells in particular, plays a critical role in pregnancy maintenance. We investigated the effects of H<inf>2</inf> on T cells and its relation to preterm birth (PTB). Main methods: Exhaled H<inf>2</inf> concentrations in pregnant women were measured and correlated with cytokine concentrations in maternal and umbilical cord blood. H<inf>2</inf> was added to T cells collected from healthy donors, and differentiation and proliferation were examined. Energy metabolism was also examined. H<inf>2</inf> was administered to mice and cytokine expression was compared. Key findings: Our prospective observational study revealed that maternal production of H<inf>2</inf> is significantly lower in pregnant women with PTB, suggesting its potential as a biomarker for predicting PTB. We found that H<inf>2</inf> has clear associations with several maternal cytokines, and acts as an immunomodulator by exerting mitochondrial function in human T cells. Moreover, in vivo administration of H<inf>2</inf> to pregnant mice regulated inflammatory responses and reduced PTB caused by T cell activation, which further supports the notion that H<inf>2</inf> may contribute to prolonged gestation through its immunomodulatory effect. Significance: Measuring maternal H<inf>2</inf>-production could be a potential clinical tool in the management of PTB, and H<inf>2</inf> may have positive impact on pregnancy maintenance.

DOI： 10.1016/j.lfs.2022.120955

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On 'Photoperoxidation in isolated chloroplasts: I. Kinetics and stoichiometry of fatty acid peroxidation' by Robert L. Heath and Lester Packer. 査読有り国際誌 Open Access

Toyokuni S, Kong Y, Mi D

Archives of biochemistry and biophysics 726 巻頁： 109133 - 109133 2022年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Archives of Biochemistry and Biophysics

This commentary concerns a highly cited paper by Robert L Heath and Lester Packer in Archives of Biochemistry and Biophysics published in 1968. Chloroplasts are organelles in algae and plants that use light energy for carbon fixation and oxygen production. These authors discovered that isolated chloroplasts exposed to visible light undergo a cyclic peroxidation of tri-unsaturated fatty acids, contributing to the double-edged sword concept of electron transfer reactions.

DOI： 10.1016/j.abb.2022.109133

Association of alcohol intake and female gender with high expression of TMPRSS2 in tongue as potential risk for SARS-CoV-2 infection. 国際誌 Open Access

Sato K, Fujii K, Yamamoto N, Ichimura N, Yamaguchi S, Yamada H, Hibi H, Toyokuni S

Journal of clinical biochemistry and nutrition 71 巻 ( 2 ) 頁： 129 - 135 2022年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Clinical Biochemistry and Nutrition

COVID-19 is pandemic since 2020 and further information is necessary on the risk factors associated with the infection of SARS-CoV-2. As an entry mechanism, SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) as receptor and transmembrane serine protease 2 (TMPRSS2) to activate fusion with host plasma membrane. Because dysgeusia is an early symptom of COVID-19, we here studied the expression of ACE2 and TMPRSS2 in the tongue and the associated tissues of mice and humans with immunohistochemistry and immunoblot analysis. ACE2 expression was low in the human tongue but was observed in the squamous epithelium, perineurium, arterial wall, salivary glands as well as taste buds. In contrast, mice showed high expression. In sharp contrast, TMPRSS2 expression was high in all the cells mentioned above in humans but relatively low in mice except for salivary glands. We then performed semiquantitation of immunohistochemistry data of human ACE2 and TMPRSS2 and analyzed for age, sex, alcohol intake, and smoking habit with logistic regression analysis. We found that alcohol intake and female gender were the significant risk factors for increasing TMPRSS2 expression. In conclusion, TMPRSS2 is an important factor to be considered regarding SARS-CoV-2 entry and amplification in the oral cavity, which is promoted through drinking habit.

DOI： 10.3164/jcbn.21-172

環境因子であるタルクおよびアスベストの卵巣発がん性とゲノム毒性の検討(Carcinogenic genome toxicity of environmental factors, asbestos and talc in ovary)

本岡大社, 鬼丸洸, 鈴木洋, 片渕充沙子, 近藤英治, 田代浩徳, 片渕秀隆, 豊國伸哉

日本癌学会総会記事 81回巻頁： P - 2007 2022年9月

BRCA1遺伝子ハプロ不全モデルラットを用いた卵巣予備能低下の検証(Validation of reduced ovarian reserve in BRCA1 haploinsufficient rats.)

曽根原玲菜, 本岡大社, 梶山広明, 真下知士, 今岡達彦, 豊國伸哉

日本癌学会総会記事 81回巻頁： P - 3012 2022年9月

BRCA1欠損はフェロトーシス抵抗性を誘導することによりアスベスト誘発性腹膜中皮腫を促進する(Ferroptosis resistance is induced by BRCA1 deficiency in asbestos-induced mesothelioma)

羅亜光, 本岡大社, 赤塚慎也, 真下知士, 今岡達彦, 豊國伸哉

日本癌学会総会記事 81回巻頁： P - 2003 2022年9月

BRCA1のハプロ不全は発がん過程において、フェロトーシス抵抗性を獲得することにより染色体増幅を促進する(BRCA1 haploinsufficiency promotes carcinogenic chromosomal amplification by ferroptosis-resistance)

孔穎怡, 赤塚慎也, 本岡大社, 鄭好, 白木之浩, 真下知士, 今岡達彦, 豊國伸哉

Biomedical Research on Trace Elements 33 巻 ( 1 ) 頁： 130 - 130 2022年9月

プラズマ活性化された乳酸リンゲルに誘導されたフェロトーシスにおけるpcbp1/2とグルタチオンとの協同作用(Cooperation of Poly(rC)-binding Proteins 1/2 and Glutathione in Ferroptosis Induced by Plasma-activated Ringer's Lactate)

鄭好, 蒋麗, 呂沁穎, 赤塚慎也, 本岡大社, 関戸好孝, 中村香江, 田中宏昌, 石川健治, 梶山広明, 水野正明, 堀勝, 豊國伸哉

日本癌学会総会記事 81回巻頁： E - 2004 2022年9月

個別化予防医療・先制医療 BRCA1のハプロ不全は、腎臓発がん過程において、フェロトーシス抵抗性を獲得することにより染色体増幅を促進する(BRCA1 haploinsufficiency promotes chromosomal amplification under renal carcinogenesis through ferroptosis-resistance)

孔穎怡, 赤塚慎也, 本岡大社, 鄭好, 白木之浩, 真下知士, 今岡達彦, 豊國伸哉

日本癌学会総会記事 81回巻頁： S20 - 7 2022年9月

環境因子であるタルクおよびアスベストの卵巣発がん性とゲノム毒性の検討(Carcinogenic genome toxicity of environmental factors, asbestos and talc in ovary)

本岡大社, 鬼丸洸, 鈴木洋, 片渕充沙子, 近藤英治, 田代浩徳, 片渕秀隆, 豊國伸哉

日本癌学会総会記事 81回巻頁： P - 2007 2022年9月

BRCA1のハプロ不全は発がん過程において、フェロトーシス抵抗性を獲得することにより染色体増幅を促進する(BRCA1 haploinsufficiency promotes carcinogenic chromosomal amplification by ferroptosis-resistance) 査読有り国際誌

孔穎怡, 赤塚慎也, 本岡大社, 鄭好, 白木之浩, 真下知士, 今岡達彦, 豊國伸哉

Biomedical Research on Trace Elements 33 巻 ( 1 ) 頁： 130 - 130 2022年9月

孔穎怡, 赤塚慎也, 本岡大社, 鄭好, 白木之浩, 真下知士, 今岡達彦, 豊國伸哉

日本癌学会総会記事 81回巻頁： S20 - 7 2022年9月

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