Updated on 2023/04/09

写真a

 
YOKOYAMA Chikako
 
Organization
Graduate School of Engineering Division of Science and Engineering for Materials, Chemistry and Biology Lecturer
School of Engineering Department of Chemistry and Bioengineering
Title
Lecturer
Affiliation
Institute of Engineering

Position

  • Graduate School of Engineering Division of Science and Engineering for Materials, Chemistry and Biology 

    Lecturer  2022.04 - Now

  • School of Engineering Department of Chemistry and Bioengineering 

    Lecturer  2022.04 - Now

Degree

  • 博士(工学) ( Osaka City University )

Research Areas

  • Life Science / Cell biology

  • Life Science / Molecular biology

  • Others / Others  / Medical biochemistry

Research Interests

  • 細胞分子生物学

  • 腫瘍生物学

  • 抗体工学

  • 分子生物学

  • 細胞生物学

  • 医化学一般

Research subject summary

  • 抗体は私たちの体の中に存在し、病原体やがん細胞が持つ特定の抗原に結合するという性質により、さまざまな病気から守ってくれる大切な生体分子です。その抗体の特性を活かし、バイオテクノロジーやバイオサイエンスにおいても非常に重要なツールとなっています。 例えば、医療の分野では、診断薬や抗体医薬などに応用され、バイオ分野の基礎研究では、がんなどの疾患や個体発生メカニズムの解明研究に用いられています。当研究室では、医療や産業分野に貢献できるモノクローナル抗体の作製や、より簡便で高効率なモノクローナル抗体作製方法の開発を目指しています。また、作製したモノクローナル抗体を用いて、がんを中心とした疾患メカニズムの解明や、治療や診断への応用研究をおこなっています。

Research Career

  • 三次元培養がん細胞に高発現する因子の同定と腫瘍形成メカニズムの解明への展開

    Individual

    2020.04 - Now 

Professional Memberships

  • 日本癌学会

    2016.02 - Now

  • 日本生物工学会

    2015.09 - Now

  • THE MOLECULAR BIOLOGY SOCIETY OF JAPAN

    2013.08 - Now

  • THE JAPANESE BIOCHEMICAL SOCIETY

    2013.05 - Now

Job Career (off-campus)

  • Osaka City University   Graduate School of Engineering Applied Chemistry and Bioengineering Course

    2021.04 - Now

  • Yamagata University   Graduate School of Science and Engineering

    2016.08 - 2021.03

  • 成蹊大学   理工学部

    2013.04 - 2016.07

  • 和歌山県立医科大学   先端医学研究所

    2011.08 - 2013.03

  • 大阪バイオサイエンス研究所   分子行動生物学研究部門

    2010.11 - 2011.07

  • 大阪府立大学   産学協同高度育成センター

    2010.04 - 2010.10

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Papers

  • Unmet Need for Reliable Immunological Detection Method for Anti-von Willebrand Factor Autoantibodies. Reviewed

    Osaki T, Souri M, Yokoyama C, Magari Y, Ichinose A

    Thrombosis and haemostasis   123 ( 4 )   478 - 481   2023.04( ISSN:0340-6245

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1055/a-2002-2394

    PubMed

  • Flow cytometric determination of ferroptosis using a rat monoclonal antibody raised against ferroptotic cells. Reviewed

    Homma T, Nishino Y, Fujii J, Yokoyama C

    Journal of immunological methods   510   113358   2022.11( ISSN:0022-1759

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.jim.2022.113358

    PubMed

  • Generation of Rat Monoclonal Antibody for Mouse Nucleolin by Immunization of Ferroptosis-Induced Hepa 1-6 Cells. Reviewed

    Yokoyama C, Kobayashi S, Harada Y, Nishino Y, Fujii J, Tachibana T

    Monoclonal antibodies in immunodiagnosis and immunotherapy   41 ( 5 )   255 - 259   2022.10

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1089/mab.2022.0005

    PubMed

  • Design, synthesis, and evaluation of the self-assembled antimicrobial peptides based on the ovalbumin-derived peptide TK913. Reviewed

    Tan A, Xu F, Yokoyama C, Yano S, Konno H

    Journal of peptide science : an official publication of the European Peptide Society   e3375   2021.11( ISSN:1075-2617

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1002/psc.3375

    PubMed

  • Nitric oxide protects against ferroptosis by aborting the lipid peroxidation chain reaction. Reviewed

    Takujiro Homma, Sho Kobayashi, Marcus Conrad, Hiroyuki Konno, Chikako Yokoyama, Junichi Fujii

    Nitric oxide : biology and chemistry   115   34 - 43   2021.10

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    Ferroptosis is a type of iron-dependent necrotic cell death, which is typically triggered by the depletion of intracellular glutathione (GSH), which is associated with increased lipid peroxidation. Nitric oxide (NO) is a highly reactive gaseous radical mediator with anti-oxidation properties that terminates lipid peroxidation reactions. In the current study, we report the anti-ferroptotic action of NOC18, an NO donor that spontaneously releases NO, in cells under various ferroptotic conditions in vitro. Our results indicate that, when mouse hepatoma Hepa 1-6 cells are incubated with NOC18, cell death induced by various ferroptotic stimuli such as cysteine (Cys) starvation, the inhibition of glutathione peroxidase 4 (GPX4) and treatment with tertiary-butyl hydroperoxide (TBHP) is significantly reduced. Treatment with NOC18 failed to improve the decrease in the levels of Cys or GSH and the accumulation of ferrous iron upon ferroptotic stimuli. The fluorescent intensity of C11-BODIPY581/591, a probe that is used to detect lipid peroxidation products, was increased somewhat by treatment with NOC18 under conditions of Cys starvation, and the accumulation of lipid peroxidation end-products, as evidenced by the levels of 4-hydroxynonenal, were effectively suppressed. The pre-incubation of TBHP with NOC7, a short-lived NO donor completely eliminated its ability to trigger ferroptosis. These collective results indicate that NO exerts a cytoprotective action against various ferroptotic stimuli by aborting the lipid peroxidation chain reaction.

    DOI: 10.1016/j.niox.2021.07.003

    PubMed

  • Generation of Rat Monoclonal Antibody for Human IQGAP1 by Immunization of Three-Dimensional-Cultured Cancer Cells. Reviewed

    Kenta Soeta, Rina Yamaguchi, Katsuya Iuchi, Hisashi Hisatomi, Chikako Yokoyama

    Monoclonal antibodies in immunodiagnosis and immunotherapy   2021.06

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    The scaffold protein IQ motif containing GTPase activating protein 1 (IQGAP1) is an adherens junction component in the epithelial tissue that binds many signaling and structural molecules to regulate biological processes. It is known that IQGAP1 is overexpressed in some tumors. In this study, we produced rat monoclonal antibodies (mAbs) through immunization of the lysate from three-dimensional (3D)-cultured DLD-1 cells to elucidate a characteristic feature of a tumor. In cancer research, 3D-cultured cancer cells are used as an intermediate model between in vitro cancer cell line cultures and in vivo tumors. Our results showed that mAb 7E11 recognized increasing antigen in the lysate of 3D-cultured cells comparing with two-dimensional-cultured cells, and its antigen is the human IQGAP1. Furthermore, we indicated that mAb 7E11 was used in immunoblotting, immunoprecipitation, and immunofluorescence staining. Therefore, it may be useful in the analysis of human cancer.

    DOI: 10.1089/mab.2020.0046

    PubMed

  • Characterization of a rat monoclonal antibody raised against ferroptotic cells. Reviewed

    Kobayashi S, Harada Y, Homma T, Yokoyama C, Fujii J

    Journal of immunological methods   489   112912   2021.02( ISSN:0022-1759

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.jim.2020.112912

    PubMed

  • Generation of Rat Monoclonal Antibody for Cytokeratin 18 by Immunization of Three-Dimensional-Cultured Cancer Cells. Reviewed

    Kenta Soeta, Katsuya Iuchi, Hisashi Hisatomi, Chikako Yokoyama

    Monoclonal antibodies in immunodiagnosis and immunotherapy   2020.10

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    Cytokeratin (CK) 18 is an intermediate filament protein that plays a major functional role in the integrity and mechanical stability of cells. Since both CK8 and CK18 are major components of simple epithelia, in the context of tumors, they are expressed in most carcinomas, and have been studied as diagnostic and prognostic markers in tumor pathology. CK18 is also cleaved by some caspases during apoptosis. Three-dimensional (3D)-cultured cancer cells are useful for cancer research as an intermediate model between in vitro cancer cell line cultures and in vivo tumors. In this study, we produced rat monoclonal antibodies (mAbs) through immunization of the lysate from 3D-cultured DLD-1 cells to elucidate a characteristic feature of a tumor, and our results showed that mAb 2H7 recognized human CK18. Furthermore, we indicated that mAb 2H7 was useful for immunoblotting, immunoprecipitation, and immunofluorescence staining. Therefore, it may be useful as a diagnostic tool for evaluating malignancy.

    DOI: 10.1089/mab.2020.0030

    PubMed

  • Antimicrobial activity and secondary structure of a novel peptide derived from ovalbumin. Reviewed

    Ao Tan, Rio Suzuki, Chikako Yokoyama, Shigekazu Yano, Hiroyuki Konno

    Journal of peptide science : an official publication of the European Peptide Society   26 ( 10 )   e3276   2020.10

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    A novel antimicrobial peptide derived from ovalbumin has been discovered. First, the peptide fragment RKIKVYLPRMK (TK9.1) was identified based on computerized predictions of the secondary structure of peptides in a protein data bank. Using HeliQuest, the sequence was developed into RKIKRYLRRMI (TK9.1.3), which was synthesized using Fmoc-solid phase peptide synthesis, and found to have strongly antimicrobial activity against Gram-positive and Gram-negative bacteria, and fungi but not cytotoxic to HeLa cells and hemolysis in mouse red blood cells. Although ovalbumin itself does not have an antibacterial activity, our results suggest that it may supply the organisms that consume it with antimicrobial peptides, in support of their immunodefence.

    DOI: 10.1002/psc.3276

    PubMed

  • Molecular phylogeny of the white-spotted charr, Salvelinus leucomaenis from Japan and the position of the S. l. japonicusmorphotype (nagaremon charr), demonstrating teleost diversification in an archipelago Reviewed

    Yasushi Arai, Toshiro Saruwatari, Takeshi Kikkou, Kazuhiro Sugahara, Yugo Sato, Saito Imada, Yusuke Katsuki, Hazuki Kashiwa, Chikako Yokoyama, Katsuya Iuchi, Hisashi Hisatomi

    Genetics and Molecular Research   2020.10

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.4238/gmr18663

  • A simple method for isolation and culture of primary hepatocytes from Salvelinus leucomaenis (White-spotted Charr) Reviewed

    Katsuya Iuchi, Yasushi Arai, Kazuki Sasaki, Naoe Sato, Chikako Yokoyama, Toshiro Saruwatari, Hisashi Hisatomi

    Springer Science and Business Media LLC Cytotechnology   2020.08( ISSN:0920-9069

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s10616-020-00415-6

    Other URL: http://link.springer.com/article/10.1007/s10616-020-00415-6/fulltext.html

  • Generation and Application of Rat Monoclonal Antibodies Specific for a Human Blood Coagulation Protein: von Willebrand Factor. Reviewed

    Chikako Yokoyama, Saki Ikeda, Tsukasa Osaki, Masayoshi Souri, Akitada Ichinose

    Monoclonal antibodies in immunodiagnosis and immunotherapy   38 ( 3 )   133 - 136   2019.06

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    von Willebrand factor (VWF) is a glycoprotein that plays a central role in the initiation of blood coagulation. VWF performs two important functions: it acts as a molecular bridge between platelets and as a carrier for coagulation factor VIII (FVIII). von Willebrand disease (VWD) and acquired von Willebrand syndrome (AVWS) are caused by the absence of and/or abnormality in VWF. The pathophysiology of VWD and AVWS is complex and, therefore, it is difficult to diagnose them by conducting the same laboratory tests in all patients. To develop useful monoclonal antibodies (mAbs) for the diagnosis of VWD and AVWS, rat mAbs against human VWF were generated. Immunoblotting analysis revealed that mAbs recognized the reduced and nonreduced VWF protein and endogenous VWF in normal human plasma. Furthermore, we developed a highly sensitive monoclonal antibody-based sandwich enzyme-linked immunosorbent assay technique. In conclusion, the development of VWF-specific mAbs would be useful in the diagnosis of VWD and AVWS.

    DOI: 10.1089/mab.2019.0008

    PubMed

  • Three populations of adult Leydig cells in mouse testes revealed by a novel mouse HSD3B1-specific rat monoclonal antibody. Reviewed

    Chikako Yokoyama, Yuta Chigi, Takashi Baba, Atsushi Ohshitanai, Yumi Harada, Fumiya Takahashi, Ken-Ichirou Morohashi

    Biochemical and biophysical research communications   511 ( 4 )   916 - 920   2019.04( ISSN:0006-291X

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    Leydig cells play a pivotal function in the synthesis of a male sex steroid, testosterone. The ability of the steroid production is dependent on the expression of the steroidogenic genes, such as HSD3B (3β-hydroxysteroid dehydrogenase/Δ5- Δ4 isomerase). It has been established that two different types of Leydig cells, fetal Leydig cells (FLCs) and adult Leydig cells (ALCs), are developed in mammalian testes. FLCs and ALCs are characterized by different sets of marker gene expression. In the case of mouse Leydig cells, Hsd3b1 (Hsd3b type 1) is expressed both in FLCs and ALCs whereas Hsd3b6 (Hsd3b type 6) is expressed in ALCs but not in FLCs. However, because the antibodies established so far for HSD3B were unable to distinguish between the HSD3B1 and HSD3B6 isoforms, it remained unclear whether both of them are expressed in every ALC. Therefore, in the present study, we generated a rat monoclonal antibody specific for mouse HSD3B1. Intriguingly, this monoclonal antibody together with an antibody specific for HSD3B6 identified three populations of ALCs based on the expression levels of these HSD3Bs.

    DOI: 10.1016/j.bbrc.2019.02.100

    PubMed

  • Oxidized unsaturated fatty acids induce apoptotic cell death in cultured cells. Reviewed

    Katsuya Iuchi, Mika Ema, Moe Suzuki, Chikako Yokoyama, Hisashi Hisatomi

    Molecular medicine reports   19 ( 4 )   2767 - 2773   2019.04( ISSN:1791-2997

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    Polyunsaturated fatty acids are oxidized by non‑enzymatic or enzymatic reactions. The oxidized products are multifunctional. In this study, we investigated how oxidized fatty acids inhibit cell proliferation in cultured cells. We used polyunsaturated and saturated fatty acids, docosahexaenoic acid (DHA; 22:6), eicosapentaenoic acid (EPA; 20:5), linoleic acid (LA; 18:2), and palmitic acid (16:0). Oxidized fatty acids were produced by autoxidation of fatty acids for 2 days in the presence of a gas mixture (20% O2 and 80% N2). We found that oxidized polyunsaturated fatty acids (OxDHA, OxEPA and OxLA) inhibited cell proliferation much more effectively compared with un‑oxidized fatty acids (DHA, EPA and LA, respectively) in THP‑1 (a human monocytic leukemia cell line) and DLD‑1 (a human colorectal cancer cell line) cells. In particular, OxDHA markedly inhibited cell proliferation. DHA has the largest number of double bonds and is most susceptible to oxidation among the fatty acids. OxDHA has the largest number of highly active oxidized products. Therefore, the oxidative levels of fatty acids are associated with the anti‑proliferative activity. Moreover, caspase‑3/7 was activated in the cells treated with OxDHA, but not in those treated with DHA. A pan‑caspase inhibitor (zVAD‑fmk) reduced the cell death induced by OxDHA. These results indicated that oxidized products from polyunsaturated fatty acids induced apoptosis in cultured cells. Collectively, the switch between cell survival and cell death may be regulated by the activity and/or number of oxidized products from polyunsaturated fatty acids.

    DOI: 10.3892/mmr.2019.9940

    PubMed

  • Analysis of genetic variation in mitochondrial cytochrome c oxidase subunit 1 between Haemadipsa japonica in Japan and land leeches worldwide Reviewed

    Naoe Sato, Chikako Yokoyama, Miki Inukai, Saeko Miyashita, Keito Nagase, Takafumi Nakano, Katsuya Iuchi, Hisashi Hisatomi

    Mitochondrial DNA Part B: Resources   4 ( 1 )   1408 - 1410   2019.01( ISSN:2380-2359

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    © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Haemadipsa japonica is the most common land leech species found in Japan. It has been considered to possess genetic variation that limits its habitat range. In the present study, to characterize variation in the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of H. japonica specimens from various locations in Japan, we examined nucleotide sequences of the mitochondrial cox1 gene. We performed PCR of mitochondrial cox1 using 10 H. japonica specimens and compared the result with those of land leeches from around the world using a maximum likelihood (ML) tree. ML tree of H. japonica in Japan showed significant differences between cox1 sequences of specimens from Yakushima and other regions of Japan. ML tree of land leeches from around the world revealed that H. japonica had the closest relationship with H. picta from Borneo.

    DOI: 10.1080/23802359.2019.1598296

  • Complete mitochondrial DNA sequences of two endemic subspecies, Salvelinus leucomaenis imbrius and Salvelinus leucomaenis pluvius (Salmonid, White spotted charr) in Japan Reviewed

    Yasushi Arai, Chikako Yokoyama, Keito Nagase, Megumi Suwa, Yuki Ogawa, Katsuya Iuchi, Hisashi Hisatomi

    Mitochondrial DNA Part B: Resources   4 ( 1 )   1522 - 1523   2019.01( ISSN:2380-2359

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    © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. The complete mitochondrial DNA (mtDNA) sequences of two endemic subspecies of the White spotted charr (Salvelinus leucomaenis) in Japan were determined. The complete mtDNA sequences of two individuals of S. l. imbrius and S. l. pluvicus were analyzed and compared with those of other charrs in GenBank. The whole mtDNA sequences of S. l. imbrius and S. l. pluvicus were 16,655 bp in length. The whole mtDNA sequence comparisons between S. leucomaenis in Japan and other charrs in GenBank, including charrs from East Asia to North American, revealed that S. l. imbrius and S. l. pluvius in Japan belonged to a different group from S. curilus (syn. S. alma krascheninnikovi), which is sympatric with S. leucomaenis in Hokkaido. Furthermore, it was discovered that the Japanese subspecies had 8 nucleotide deletions and four nucleotide insertions compared with S. curilus.

    DOI: 10.1080/23802359.2019.1601517

  • Induction of oxidative stress by anticancer drugs in the presence and absence of cells Reviewed

    Chikako Yokoyama, Yuto Sueyoshi, Mika Ema, Yumi Mori, Kazuto Takaishi, Hisashi Hisatomi

    SPANDIDOS PUBL LTD ONCOLOGY LETTERS   14 ( 5 )   6066 - 6070   2017.11( ISSN:1792-1074

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    Reactive oxygen species (ROS) are generated in the cell through multiple mechanisms. Intracellular ROS are rapidly detoxified by various enzymatic and non-enzymatic mechanisms; however, disruption of the oxidant-antioxidant balance causes oxidative stress and elicits cell damage. The oxidative stress induced by chemotherapy is known to cause side effects in patients with cancer. However, few studies have examined whether anticancer drugs induce oxidative stress in cancer cells. Furthermore, the precise mechanism by which anticancer drugs induce the generation of ROS remains unclear. In the present study, to investigate whether anticancer drugs induce oxidative stress, DLD-1 human colorectal cancer cells were treated with 20 different anticancer drugs and then stained with CellROX (R) ROS detection reagent. Furthermore, an oxygen radical absorbance capacity assay in the presence of copper was performed to estimate the oxidative activities of the anticancer drugs in the absence of cells. The data of the present study using assay methods in the presence and absence of cells suggest that nimustine, actinomycin D, doxorubicin, mitomycin C, mitoxantrone, carmofur, gemcitabine, mercaptopurine, camptothecin, paclitaxel, vinblastine, and vinorelbine are able to induce oxidative stress.

    DOI: 10.3892/ol.2017.6931

    PubMed

  • Interleukin-8 enhances the effect of colchicine on cell death Reviewed

    Chikako Yokoyama, Chika Yajima, Tetsuro Machida, Yuji Kawahito, Marie Uchida, Hisashi Hisatomi

    ACADEMIC PRESS INC ELSEVIER SCIENCE BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   485 ( 1 )   89 - 94   2017.03( ISSN:0006-291X

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    Pro-inflammatory cytokines are known to be generated in tumors and play important roles in angiogenesis, mitosis, and tumor progression. However, few studies have investigated the synergistic effects of pro-inflammatory cytokines and anticancer drugs on cell death. In the present study, we examined the combined effects of pro-inflammatory cytokines and colchicine on cell death of cancer cells. Colchicine induces G2/M arrest in the cell cycle by binding to tubulin, one of the main constituents of microtubules. SUIT-2 human pancreatic cancer cell line cells overexpressing pro-inflammatory cytokines, including interleukin (IL)-1 beta, IL-8, and tumor necrosis factor (TNF)-alpha, were treated with colchicine. The effect of colchicine on cell death was enhanced in cells overexpressing IL-8. Moreover, the effect of colchicine on cell death was enhanced in cells overexpressing two IL-8 up-regulators, NF-kappa B and IL-6, but not in cells overexpressing an IL-8 down-regulator, splicing factor proline/glutamine-rich (SFPQ). Synergistic effects of IL-8 and colchicine were also observed in cells overexpressing 1L-8 isoforms lacking the signal peptide. Therefore, IL-8 appeared to function as an enhancer of cell death in cancer cells treated with colchicine. The present results suggest a new role for IL-8 related to cell death of cancer cells. (C) 2017 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.bbrc.2017.02.025

    PubMed

  • Application of Monoclonal Antibodies Against Mouse Dermokine Reviewed

    Kiyoshi Higashi, Cai-Xia Wang, Chikako Yokoyama, Keita Yamada, Koichi Saito, Taro Tachibana

    Mary Ann Liebert Inc. Monoclonal Antibodies in Immunodiagnosis and Immunotherapy   36 ( 1 )   15 - 19   2017.02( ISSN:2167-9436

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    Dermokine is one of the most highly expressed proteins in differentiating keratinocytes. Mouse dermokine has been reported to be encoded by 22 exons, and its expression leads to three transcripts, β, γ, and α, which are transcribed from two different transcriptional start sites. The α isoform represents the carboxyl-terminal domain of the β isoform, whereas the γ isoform lacks this domain. To reveal the distributions and expression levels of each isoform in mice, we generated rat monoclonal antibodies against dermokine-β/γ and dermokine-β/α. In immunofluorescence studies, the expression levels of dermokine in the cytosol of the cultured mouse keratinocytes were significantly elevated by high levels of extracellular calcium. In Western blot analyses, the expression levels of dermokine-β and dermokine-α were increased in the presence of high calcium. Finally, we developed a monoclonal antibody-based sensitive sandwich enzyme-linked immunosorbent assay (ELISA) and showed that the secreted dermokine-β into the culture medium from mouse keratinocytes was significantly increased in a manner dependent on the extracellular calcium concentration. These dermokine-specific antibodies have allowed us to gain new insights into the role of each dermokine isoform in cutaneous homeostasis.

    DOI: 10.1089/mab.2016.0051

    PubMed

  • Alternative splicing isoform in succinate dehydrogenase complex, subunit C causes downregulation of succinate-coenzyme Q oxidoreductase activity in mitochondria Reviewed

    Nana Satoh, Chikako Yokoyama, Noriaki Itamura, Yoshiharu Miyajima-Nakano, Hisashi Hisatomi

    SPANDIDOS PUBL LTD ONCOLOGY LETTERS   9 ( 1 )   330 - 334   2015.01( ISSN:1792-1074

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    Mitochondrial succinate dehydrogenase (SDH) is localized to the inner mitochondrial membrane and is responsible for the redox of succinic acid. SDH is a tetrameric iron-sulfur flavoprotein of the tricarboxylic acid cycle and respiratory chain. The SDH complex, subunit C (SDHC) transcript has deletion-type alternative splicing sites. Generally, alternative splicing produces variant proteins and expression patterns, as products of different genes. In certain cases, specific alternative splicing variants (ASVs) have been associated with human disease. Due to a frameshift mutation causing loss of the heme binding region, the SDHC 5 isoform (lacking exon 5) exhibits no SDHC activity. To investigate whether the SDHC splicing variants can function as dominant-negative inhibitors, SDHC ASVs were overexpressed in HCT-15 human colorectal cancer cells. Using real-time reverse transcription-polymerase chain reaction, a dominant-negative effect of the 5 isoform on SDHC mRNA was shown. In addition, 5 overexpression increased the levels of reactive oxygen species. Furthermore, in the 5 isoform-overexpressing cells, SDH activity was reduced. SDHC activation is a significant event during the electron transport chain, and the function of the SDHC 5 variant may be significant for the differentiation of tumor cells.

    DOI: 10.3892/ol.2014.2699

    PubMed

  • Mitochondrial DNA reduced by hypoxic conditions in three-dimensional (3D) spheroid cell cultures Reviewed

    Mayumi Chiba, Chikako Yokoyama, Mai Okada, Hisashi Hisatomi

    SPRINGER TUMOR BIOLOGY   35 ( 12 )   12689 - 12693   2014.12( ISSN:1010-4283

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    Three-dimensional (3D) cell culture reflects many of the important properties of solid tumors, such as the inadequate diffusion of oxygen that results in hypoxia. To understand the mitochondrial states in cancer, we performed comparisons of the levels of mitochondrial DNA (mtDNA), fusion-and fission-related mitochondrial messenger RNA (mRNA), and mitochondrial protein expression between monolayer (2D)- and 3D-cultured cancer cells. The mtDNA levels were observed to be significantly lower in the 3D cells compared with the monolayer cells. In contrast, the differences in expression of the mitochondrial fusion- and fission-related mRNAs and mitochondrial proteins between 2D- and 3D-cultured cancer cells were not significant, as shown by real-time PCR and immunoblot analysis. Therefore, although mtDNA levels decrease as a whole during 3D culture, this does not appear to affect the fusion and fission of individual mitochondria. Indeed, the factors regulating mitochondrial dynamics during 3D cell culture remain unclear. This study provides the basis for future, more detailed studies on the regulation of mtDNA.

    DOI: 10.1007/s13277-014-2593-6

    PubMed

  • Sexually dimorphic expression of Mafb regulates masculinization of the embryonic urethral formation Reviewed

    Kentaro Suzuki, Tomokazu Numata, Hiroko Suzuki, Dennis Diana Raga, Lerrie Ann Ipulan, Chikako Yokoyama, Shoko Matsushita, Michito Hamada, Naomi Nakagata, Ryuichi Nishinakamura, Shoen Kume, Satoru Takahashi, Gen Yamada

    NATL ACAD SCIENCES PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   111 ( 46 )   16407 - 16412   2014.11( ISSN:0027-8424

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    Masculinization of external genitalia is an essential process in the formation of the male reproductive system. Prominent characteristics of this masculinization are the organ size and the sexual differentiation of the urethra. Although androgen is a pivotal inducer of the masculinization, the regulatory mechanism under the control of androgen is still unknown. Here, we address this longstanding question about how androgen induces masculinization of the embryonic external genitalia through the identification of the v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog B (Mafb) gene. Mafb is expressed prominently in the mesenchyme of male genital tubercle (GT), the anlage of external genitalia. MAFB expression is rarely detected in the mesenchyme of female GTs. However, exposure to exogenous androgen induces its mesenchymal expression in female GTs. Furthermore, MAFB expression is prominently down-regulated in male GTs of androgen receptor (Ar) KO mice, indicating that AR signaling is necessary for its expression. It is revealed that Mafb KO male GTs exhibit defective embryonic urethral formation, giving insight into the common human congenital anomaly hypospadias. However, the size of Mafb KO male GTs is similar with that of wild-type males. Moreover, androgen treatment fails to induce urethral masculinization of the GTs in Mafb KO mice. The current results provide evidence that Mafb is an androgen-inducible, sexually dimorphic regulator of embryonic urethral masculinization.

    DOI: 10.1073/pnas.1413273111

    PubMed

  • Altered expression of dermokine in skin disorders Reviewed

    M. Hasegawa, K. Higashi, C. Yokoyama, F. Yamamoto, T. Tachibana, T. Matsushita, Y. Hamaguchi, K. Saito, M. Fujimoto, K. Takehara

    7 Journal of the European Academy of Dermatology and Venereology   27 ( 7 )   867 - 875   2013.07( ISSN:0926-9959

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    Publishing type:Research paper (scientific journal)  

    Background Although dermokine-β, a glycoprotein expressed in epithelial cells, does not have significant homology to other proteins, its carboxyl-terminal domain shares a high pI value with many cytokines, suggesting similar functions. Objective To better understand the biology of dermokine, we here determined its localization under pathological conditions and examined factors that regulate its expression. Methods We generated an anti-human dermokine-β/γ monoclonal antibody cross-reacting with the mouse protein. Using this antibody, immunohistological staining and Western blotting of dermokine-β/γ were performed with various tissue samples. Results Although human dermokine-β/γ was expressed in almost all granular layers, upper spinous layers of the skin were also stained with anti-dermokine-β/γ antibody in inflammatory skin disorders. Dermokine-β/γ was expressed in keratoacanthoma and a part of well-differentiated squamous cell carcinoma (SCC). However, dermokine-β/ γ was not detected in poorly differentiated SCC or tumours derived from non-keratinocytes. In mice, dermokine-β/γ-expressed keratinocytes were increased in models of contact hypersensitivity, ultraviolet-irradiated skin injury and wound healing. Consistent with expanded distribution in inflammatory skin diseases, proinflammatory cytokines such as interleukin-1β, interleukin-12, and tumour necrosis factor-α augmented dermokine-β/γ expression in cultured human keratinocytes. In contrast, growth factors including epidermal growth factor, insulin-like growth factor-I, keratinocyte growth factor and transforming growth factor-α significantly reduced dermokine expression. Conclusion These results provide novel insights into the physiological and pathological significance of dermokine in the epidermis. © 2012 European Academy of Dermatology and Venereology.

    DOI: 10.1111/j.1468-3083.2012.04598.x

    PubMed

  • Wakayama Symposium: Epithelial-Mesenchymal Interaction Regulates Tissue Formation and Characteristics: Insights for Corneal Development Reviewed

    Kentaro Suzuki, Chikako Yokoyama, Yujiro Higashi, Takiko Daikoku, Shin Mizoguchi, Shizuya Saika, Gen Yamada

    ETHIS COMMUNICATINS, INC OCULAR SURFACE   10 ( 4 )   217 - 220   2012.10( ISSN:1542-0124

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    Epithelial-mesenchymal interactions and epithelial-to-mesenchymal transition (EMT) are essential during tissue formation and organ morphogenesis. The roles of Wnt/beta-catenin signaling have been studied in many organ systems. In this review, we describe the importance of Wnt/beta-catenin signaling by comparing skin and corneal development of Wnt/beta-catenin gain of function (GOF) mutant mice. In the skin, Wnt/beta-catenin signals have been suggested to play essential roles in regulating cell-cell interaction, cell proliferation and differentiation. Wnt signaling may be associated with basal cell carcinoma (BCC) of the skin. In the case of cornea, beta-catenin GOF mutation leads to epithelial hyperplasia. Investigation of the mechanisms of growth factor signaling as a reference to general organogenesis could provide profound insights for understanding corneal development and pathogenesis.

    DOI: 10.1016/j.jtos.2012.07.007

    PubMed

  • Dermokine-beta impairs ERK signaling through direct binding to GRP78 Reviewed

    Kiyoshi Higashi, Minoru Hasegawa, Chikako Yokoyama, Taro Tachibana, Shinichi Mitsui, Koichi Saito

    ELSEVIER SCIENCE BV, FEBS LETTERS   586 ( 16 )   2300 - 2305   2012.07( ISSN:0014-5793

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    Dermokine-beta is abundant in stratified epithelia and in differentiating cultured keratinocytes. In this study, we investigated the role of dermokine-beta in differentiation of keratinocytes. Treatment of keratinocytes or skin tumor cells with dermokine-beta attenuated phosphorylation of extracellular-signal-regulated kinase (ERK). Exposure of cells to dermokine-beta, as well as its carboxyl-terminus domain peptide, interrupted phosphorylation of ERK and stimulated dermokine gene expression. Inhibition of ERK signaling by its specific inhibitor also increased dermokine expression level. A combination of chemical cross-linking and immunoprecipitation, followed by proteomics analyses, identified glucose-regulated protein 78 (GRP78) as a dermokine-beta-associated protein. Blockage of GRP78 expression by a specific siRNA abrogated actions of dermokine-beta. These findings provide novel insights into the physiological significance of dermokine-beta in the epidermis.

    DOI: 10.1016/j.febslet.2012.06.022

    PubMed

  • Promotion of non-rapid eye movement sleep in mice after oral administration of ornithine Reviewed

    Ken Omori, Yoshiaki Kagami, Chikako Yokoyama, Tomoko Moriyama, Naomi Matsumoto, Mika Masaki, Hiroyasu Nakamura, Hiroshi Kamasaka, Koso Shiraishi, Takashi Kometani, Takashi Kuriki, Zhi-Li Huang, Yoshihiro Urade

    WILEY-BLACKWELL SLEEP AND BIOLOGICAL RHYTHMS   10 ( 1 )   38 - 45   2012.01( ISSN:1446-9235

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    We examined the effects of ornithine on the sleepwake cycle by monitoring the electroencephalogram, electromyogram, and locomotor activity of freely moving mice after oral administration of it at lights-off time (18:00). Ornithine (1.0 and 3.0 g/kg of body weight) increased the amount of nonrapid eye movement (non-REM, NREM) sleep for 2 h after its administration, with a peak at 60 min post administration, to 164% and 198%, respectively, of that of the vehicle-administered mice, without changing the amount of REM sleep. The administration of ornithine at a lower dose (0.3 g/kg of body weight) did not increase the amount of NREM sleep compared with the vehicle administration. Ornithine did not affect the power spectrum density of NREM sleep but increased the number of episodes of wakefulness and NREM sleep and that of transitions between wakefulness and NREM sleep, and decreased the mean duration of wake episodes in a dose-dependent manner for 2 h after the oral administration. These results indicate that ornithine increased the amount of NREM sleep without reducing the power spectrum density of NREM sleep.

    DOI: 10.1111/j.1479-8425.2011.00515.x

    J-GLOBAL

  • Production and Characterization of Monoclonal Antibodies to Mouse Germ Cells Reviewed

    Chikako yokoyama, Yuko Katoh-Fukui, Ken-ichirou Morohashi, Daijiro Konno, Masayuki Azuma, Taro Tachibana

    MARY ANN LIEBERT INC HYBRIDOMA   29 ( 1 )   53 - 57   2010.02( ISSN:1554-0014

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    In mammals, primordial germ cells (PGCs) are generated in the extra-embryonic epiblast, and thereafter migrate into the developing gonads. Following the development of the gonads to the testes or ovaries, germ cells mature into sperms or eggs. In the present study, we report production and characterization of monoclonal antibodies (MAb) that recognize PGCs. Extracts from E12.5 mouse embryonic gonads were immunized as an antigen, and hybridomas were generated using the rat medial iliac lymph node method. The hybridoma supernatants were screened by immunohistochemical analyses of E12.5 mouse embryonic sections. The antibody, referred to herein as MAb 5B5, provided strong signals on PGCs. Moreover, immunofluorescence analyses using a variety of the tissue sections of mouse embryos revealed that MAb 5B5 also recognizes the ventricular zone of the cerebral cortex and the neural canal in the spinal cord in which neural specific stem cells are present in abundance. Based on these findings, MAb 5B5 might recognize stem cell-associated antigens.

    DOI: 10.1089/hyb.2009.0101

    PubMed

  • Molecular characterization and expression of the low-density lipoprotein receptor-related protein-10, a new member of the LDLR gene family Reviewed

    Young-Hee Jeong, Kayoko Ishikawa, Yoshimi Someya, Akemi Hosoda, Tomohiko Yoshimi, Chikako Yokoyama, Sumiko Kiryu-Seo, Man-Jong Kang, Taro Tchibana, Hiroshi Kiyama, Tomoe Fukumura, Dong-Ho Kim, Shigeru Saeki

    ACADEMIC PRESS INC ELSEVIER SCIENCE BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   391 ( 1 )   1110 - 1115   2010.01( ISSN:0006-291X

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    We report the characterization of a new member of the low-density lipoprotein receptor (LDLR) gene family designated LRP10. Human LRP10 cDNA encodes a 1905 amino acid type I membrane protein consisting of five functional domains characteristic of the LDLR gene family. CHO-ldlA7 cells transfected with human LRP10 cDNA bound LDLR-associated protein, but not beta-VLDL and HDL. Human LRP10 transcripts were primarily found in the brain, muscle and heart. in situ hybridization of the rat brain showed that the transcripts were intensely present in the cerebral cortex, hippocampus, choroid plexus, ependyma and granular layer. In the developing rat brain, transcript levels gradually increased from postnatal day 1 to 20. Immunofluorescence analysis indicated that LRP10 was observed in the ventricular zone of the embryonic day 14.5 mouse cerebral cortex. The present studies suggest that LRP10 may play a significant role in the brain physiology other than lipoprotein metabolism. (C) 2009 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.bbrc.2009.12.033

    PubMed

  • Generation of Rat Monoclonal Antibodies Specific for Ad4BP/SF-1 Reviewed

    Chikako Yokoyama, Tomoko Komatsu, Hidesato Ogawa, Ken-ichirou Morohashi, Masayuki Azuma, Taro Tachibana

    MARY ANN LIEBERT, INC HYBRIDOMA   28 ( 2 )   113 - 119   2009.04( ISSN:1554-0014

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    Ad4BP/SF-1 (adrenal4 binding protein/steroidogenic factor-1[NR5A1]) is an essential nuclear receptor required for animal reproduction and endocrine regulation. The present study reports on monoclonal antibodies (MAbs) directed against mouse Ad4BP/SF-1, which were produced by the hybridization of mouse myeloma cells with lymph node cells of an immunized rat. The produced MAbs reacted with both recombinant and endogenous Ad4BP/SF-1. These MAbs will be useful in immunolocalization and immunoblotting experiments conducted on different tissue types to determine the levels of expression of Ad4BP/SF-1 throughout development, as well as further analyses of the biological function and cellular dynamics of this protein.

    DOI: 10.1089/hyb.2008.0084

    PubMed

  • Pituitary homeobox 2 regulates adrenal4 binding protein/steroidogenic factor-1 gene transcription in the pituitary gonadotrope through interaction with the intronic enhancer Reviewed

    Yuichi Shima, Mohamad Zubair, Tomoko Komatsu, Sanae Oka, Chikako Yokoyama, Taro Tachibana, Tord A. Hjalt, Jacques Drouin, Ken-ichirou Morohashi

    ENDOCRINE SOC MOLECULAR ENDOCRINOLOGY   22 ( 7 )   1633 - 1646   2008.07( ISSN:0888-8809

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    Ad4BP/SF-1 [adrenal4 binding protein/steroidogenic factor-1 (NR5A1)] is a factor important for animal reproduction and endocrine regulation, and its expression is tightly regulated in the gonad, adrenal gland, ventromedial hypothalamic nucleus, and pituitary gonadotrope. Despite its functional significance in the pituitary, the mechanisms underlying pituitary-specific expression of the gene remain to be uncovered. In this study, we demonstrate by transgenic mouse assays that the pituitary gonadotrope-specific enhancer is localized within the sixth intron of the gene. Functionally, the enhancer recapitulates endogenous Ad4BP/SF-1 expression in the fetal Rathke's pouch to the adult pituitary gonadotrope. Structurally, the enhancer consists of several elements conserved among animal species. Mutational analyses confirmed the significance of these elements for the enhancer function. One of these elements was able to interact both in vitro and in vivo with Pitx2 (pituitary homeobox 2), demonstrating that pituitary homeobox 2 regulates Ad4BP/SF-1 gene transcription in the pituitary gonadotrope via interaction with the gonadotrope-specific enhancer.

    DOI: 10.1210/me.2007-0444

    PubMed

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MISC

  • 凝固第XIII因子の非酵素サブユニット認識抗体によるフィブリン架橋阻害 Reviewed

    惣宇利正善, 横山智哉子, 尾崎司, 和田秀穂, 一瀬白帝

    日本血栓止血学会誌   30 ( 2 )   434   2019.05( ISSN:0915-7441

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    J-GLOBAL

  • ヒト血液凝固関連von Willebrand因子特異的ラットモノクローナル抗体の樹立と性状解析 Reviewed

    横山智哉子, 尾崎司, 惣宇利正善, 一瀬白帝

    (公社)日本生化学会, 日本生化学会大会(Web)   91st   ROMBUNNO.3P‐380 (WEB ONLY) - 380]   2018.09

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    J-GLOBAL

  • 抗がん剤候補化合物MF4426結合タンパク質の同定 Reviewed

    矢島 知佳, 横山 智哉子, 久富 寿

    成蹊大学理工学研究報告   53 ( 1 )   39 - 40   2016

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  • 制限酵素によるDNA消化条件の最適化 Reviewed

    横山 智哉子, 依馬 未佳, 小川 有貴, 河村 憲, 小林 汀弥, 矢島 知佳, 林 優香子, 村上 千佳, 森 裕美, 久富 寿

    成蹊大学理工学研究報告   52 ( 1 )   28 - 28   2015

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  • 低酸素状態におけるミトコンドリオン数の変化 Reviewed

    千葉 真弓, 岡田 真衣, 横山 智哉子, 久富 寿

    成蹊大学理工学研究報告   50 ( 2 )   107 - 108   2013

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Presentations

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Charge of on-campus class subject

  • 化学バイオ工学演習A

    2021     Undergraduate

  • 細胞生物学

    2021     Undergraduate