Details of the Researcher

PHOTO

Towako Kajiyama
Section
Graduate School of Life Sciences
Job title
Assistant Professor
Degree

  • 博士（農学）（東京大学）

  • 修士（農学）（東京大学）

Research History 5

  • 2023/08 - Present
    RIKEN　Center for Brain Science

  • 2023/08 - Present
    Tohoku University　Graduate School of Life Sciences

  • 2019/06 - 2023/07
    理化学研究所

  • 2015/04 - 2019/05
    理化学研究所　脳神経科学研究センター　基礎科学特別研究員

  • 2012/04 - 2015/03
    日本学術振興会特別研究員（DC1）

Education 3

  • 東京大学大学院　農学生命科学研究科　水圏生物科学専攻（博士課程）

    2012/04 - 2015/03

  • 東京大学大学院　農学生命科学研究科　水圏生物科学専攻（修士課程）

    2010/04 - 2012/03

  • The University of Tokyo

    2006/04 - 2010/03

Professional Memberships 3

  • 日本比較内分泌学会

    2022 - Present

  • Japan Neuroscience Society

    - Present

  • THE JAPANESE ASSOCIATION FOR THE STUDY OF TASTE AND SMELL

    - Present

Research Interests 4

  • 内分泌

  • 生殖

  • 神経回路

  • 行動

Research Areas 2

  • Life sciences / Marine/Aquatic life sciences /

  • Life sciences / Neuroscience - general /

Awards 6

  1. 桜舞賞

    2025/03　理化学研究所

  2. 研究奨励賞

    2025/01　東北大学生命科学研究科

  3. Mimosa Award

    2024/03

  4. 研究科長賞

    2015　東京大学大学院農学生命科学研究科

  5. Best Student’s Oral Presentation

    2014　10th International Symposium on Reproductive Physiology of Fish

  6. Best Poster Presentation

    2012　9th International Symposium on Reproductive Physiology of Fish

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Papers 13

  1. Single-Cell RNA-Sequencing of Zebrafish Olfactory Epithelium Identifies Odor-Responsive Candidate Olfactory Receptors. International-journal Peer-reviewed

    Misaki Takaoka, Towako Hiraki-Kajiyama, Nobuhiko Miyasaka, Takahiro Hino, Kenji Kondo, Yoshihiro Yoshihara

    Genes to cells : devoted to molecular & cellular mechanisms　30　(1)　e13191　2025/01

    DOI： 10.1111/gtc.13191 　

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    Single-cell RNA-sequencing (scRNA-seq) is a powerful method to comprehensively overlook gene expression profiles of individual cells in various tissues, providing fundamental datasets for classification of cell types and further functional analyses. Here we adopted scRNA-seq analysis for the zebrafish olfactory sensory neurons which respond to water-borne odorants and pheromones to elicit various behaviors crucial for survival and species preservation. Firstly, a single-cell dissociation procedure of the zebrafish olfactory rosettes was optimized by using cold-active protease, minimizing artifactual neuronal activation. Secondly, various cell types were classified into distinct clusters, based on the expressions of well-defined marker genes. Notably, we validated non-overlapping expressions of different families of olfactory receptors among the clusters of olfactory sensory neurons. Lastly, we succeeded in estimating candidate olfactory receptors responding to a particular odor stimulus by carefully scrutinizing correlated expressions of immediate early genes. Thus, scRNA-seq is a useful measure for the analysis of olfactory sensory neurons not only in classifying functional cell types but also in identifying olfactory receptor genes for given odorants and pheromones.

  2. The Medaka Approach to Evolutionary Social Neuroscience Peer-reviewed

    Satoshi ANSAI, Towako HIRAKI-KAJIYAMA, Ryutaro UEDA, Takahide SEKI, Saori YOKOI, Takafumi KATSUMURA, Hideaki TAKEUCHI

    Neuroscience Research　2024/10

    Publisher: Elsevier BV

    DOI： 10.1016/j.neures.2024.10.005 　

    ISSN： 0168-0102

  3. Unilateral Chasing and Courtship-Like Display as Dominance Signals for Hierarchy Maintenance in Male Medaka Fish

    Yuji Mitsutsuji, Mayuko Suzuki, Ryo Umeda, Satoshi Ansai, Fumitaka Ueoka, Zou Jingyi, Anna Yamaguchi, Towako Hiraki-Kajiyama, Tetsuro Takeuchi, Maho Ogoshi, Takafumi Katsumura, Saori Yokoi, Hideaki Takeuchi

    Research Square　2024/09

    DOI： 10.21203/rs.3.rs-4837620/v1 　

  4. An atlas and database of neuropeptide gene expression in the adult zebrafish forebrain. International-journal Peer-reviewed

    Towako Hiraki-Kajiyama, Nobuhiko Miyasaka, Reiko Ando, Noriko Wakisaka, Hiroya Itoga, Shuichi Onami, Yoshihiro Yoshihara

    The Journal of comparative neurology　532　(6)　e25619　2024/06

    DOI： 10.1002/cne.25619 　

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    Zebrafish is a useful model organism in neuroscience; however, its gene expression atlas in the adult brain is not well developed. In the present study, we examined the expression of 38 neuropeptides, comparing with GABAergic and glutamatergic neuron marker genes in the adult zebrafish brain by comprehensive in situ hybridization. The results are summarized as an expression atlas in 19 coronal planes of the forebrain. Furthermore, the scanned data of all brain sections were made publicly available in the Adult Zebrafish Brain Gene Expression Database (https://ssbd.riken.jp/azebex/). Based on these data, we performed detailed comparative neuroanatomical analyses of the hypothalamus and found that several regions previously described as one nucleus in the reference zebrafish brain atlas contain two or more subregions with significantly different neuropeptide/neurotransmitter expression profiles. Subsequently, we compared the expression data in zebrafish telencephalon and hypothalamus obtained in this study with those in mice, by performing a cluster analysis. As a result, several nuclei in zebrafish and mice were clustered in close vicinity. The present expression atlas, database, and anatomical findings will contribute to future neuroscience research using zebrafish.

  5. Neuropeptide B mediates female sexual receptivity in medaka fish, acting in a female-specific but reversible manner. Peer-reviewed

    Hiraki-Kajiyama T, Yamashita J, Yokoyama K, Kikuchi Y, Nakajo M, Miyazoe D, Nishiike Y, Ishikawa K, Hosono K, Kawabata-Sakata Y, Ansai S, Kinoshita M, Nagahama Y, Okubo K

    eLife　8　e39495　2019/08

    DOI： 10.7554/eLife.39495 　

    ISSN： 2050-084X

  6. Sexually dimorphic neuropeptide B neurons in medaka exhibit activated cellular phenotypes dependent on estrogen. Peer-reviewed

    Kikuchi Y, Hiraki-Kajiyama T, Nakajo M, Umatani C, Kanda S, Oka Y, Matsumoto K, Ozawa H, Okubo K

    Endocrinology　160　(4)　827-839　2019/04

    DOI： 10.1210/en.2019-00030 　

    ISSN： 0013-7227

    eISSN： 1945-7170

  7. An Adenosine Receptor for Olfaction in Fish Peer-reviewed

    Noriko Wakisaka, Nobuhiko Miyasaka, Tetsuya Koide, Miwa Masuda, Towako Hiraki-Kajiyama, Yoshihiro Yoshihara

    CURRENT BIOLOGY　27　(10)　1437-+　2017/05

    DOI： 10.1016/j.cub.2017.04.014 　

    ISSN： 0960-9822

    eISSN： 1879-0445

  8. Three urocortins in medaka: identification and spatial expression in the central nervous system Peer-reviewed

    K. Hosono, J. Yamashita, Y. Kikuchi, T. Hiraki-Kajiyama, K. Okubo

    JOURNAL OF NEUROENDOCRINOLOGY　29　(5)　2017/05

    DOI： 10.1111/jne.12472 　

    ISSN： 0953-8194

    eISSN： 1365-2826

  9. Teleocortin: A Novel Member of the CRH Family in Teleost Fish Peer-reviewed

    Kohei Hosono, Yukiko Kikuchi, Hiroshi Miyanishi, Towako Hiraki-Kajiyama, Akio Takeuchi, Kiyoshi Nakasone, Sayaka Maehiro, Kataaki Okubo

    ENDOCRINOLOGY　156　(8)　2949-2957　2015/08

    DOI： 10.1210/en.2015-1042 　

    ISSN： 0013-7227

    eISSN： 1945-7170

  10. Neuropeptide B Is Female-Specifically Expressed in the Telencephalic and Preoptic Nuclei of the Medaka Brain Peer-reviewed

    Towako Hiraki, Kiyoshi Nakasone, Kohei Hosono, Yukika Kawabata, Yoshitaka Nagahama, Kataaki Okubo

    ENDOCRINOLOGY　155　(3)　1021-1032　2014/03

    DOI： 10.1210/en.2013-1806 　

    ISSN： 0013-7227

    eISSN： 1945-7170

  11. Sexually dimorphic expression of the sex chromosome-linked genes cntfa and pdlim3a in the medaka brain Peer-reviewed

    Sayaka Maehiro, Akio Takeuchi, Junpei Yamashita, Towako Hiraki, Yukika Kawabata, Kiyoshi Nakasone, Kohei Hosono, Takeshi Usami, Bindhu Paul-Prasanth, Yoshitaka Nagahama, Yoshitaka Oka, Kataaki Okubo

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS　445　(1)　113-119　2014/02

    DOI： 10.1016/j.bbrc.2014.01.131 　

    ISSN： 0006-291X

    eISSN： 1090-2104

  12. Female-specific target sites for both oestrogen and androgen in the teleost brain Peer-reviewed

    Towako Hiraki, Akio Takeuchi, Takayasu Tsumaki, Buntaro Zempo, Shinji Kanda, Yoshitaka Oka, Yoshitaka Nagahama, Kataaki Okubo

    PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES　279　(1749)　5014-5023　2012/12

    DOI： 10.1098/rspb.2012.2011 　

    ISSN： 0962-8452

  13. SEX DIFFERENCES IN THE EXPRESSION OF VASOTOCIN/ISOTOCIN, GONADOTROPIN-RELEASING HORMONE, AND TYROSINE AND TRYPTOPHAN HYDROXYLASE FAMILY GENES IN THE MEDAKA BRAIN Peer-reviewed

    Y. Kawabata, T. Hiraki, A. Takeuchi, K. Okubo

    NEUROSCIENCE　218　65-77　2012/08

    DOI： 10.1016/j.neuroscience.2012.05.021 　

    ISSN： 0306-4522

    eISSN： 1873-7544

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Misc. 1

  1. 魚類における脳の性分化

    平木十和子, 大久保範聡

    比較内分泌学　40　(152)　67-69　2014

    DOI： 10.5983/nl2008jsce.40.67 　

Presentations 22

  1. Sex differences in the medaka brain revealed by single-cell transcriptomic analysis Invited

    Towako Hiraki-Kajiyama

    2025/07

  2. Sexual Dimorphism in the Optic Tectum of Medaka Revealed by Single-Cell RNA-Sequencing

    Towako Hiraki-Kajiyama, Kanako Mizukuchi, Lu Yongxun, Kazuki Yamada, Yoshinori Hayakawa, Lucas Dammers, Mao Eguchi, Yuji Nishiike, Daichi Kayo, Yuu Korai, Anna Yamaguchi, Ryutaro Ueda, Asahi Hamasaki, Shuji Shigenobu, Yasuhiro Go, Haruka Ozaki, Kataaki Okubo, Hideaki Takeuchi, Satoshi Ansai

    19th International Congress of Comparative Endocrinology　2025/07

  3. Elucidating brain sex and species differences in small teleost fish via single-cell transcriptome analysis

    Towako Hiraki-Kajiyama, Lu Yongxun, Lucas Dammers, Kanako Mizukuchi, Anna Yamaguchi, Yoshinori Hayakawa, Yuuji Nishiike, Daichi Kayo, Ryutaro Ueda, Asahi Hamasaki, Haruka Ozaki, Yasuhiro Go, Shuji Shigenobu, Kataaki Okubo, Satoshi Ansai, Hideaki Takeuchi

    2025/06

  4. シングルセルRNA-seqを用いた小型魚類の視蓋の種差・性差解析 Invited

    梶山十和子

    超階層生物学 Joint WorkShop 2025　2025/03/04

  5. Atlas and Database of Neuropeptide Expression in the Zebrafish Brain and Their Application to Comparative Neuroanatomy Invited

    Towako Hiraki-Kajiyama

    CBS Young Investigator's Seminar　2025/02/07

  6. Single-cell RNA-sequencing によるメダカの脳の性差の解析

    梶山十和子

    第7回脳と生殖研究会　2024/11/29

  7. Construction of the cell type atlas of medaka telencephalon and optic tectum by single-cell RNA-seq

    2024/10/17

  8. Neuropeptide Expression in the Adult Zebrafish Forebrain -Atlas, Database and Comparison with Mice-

    Towako Hiraki-Kajiyama, Nobuhiko Miyasaka, Reiko Ando, Noriko Wakisaka, Hiroya Itoga, Shuichi Onami, Yoshihiro Yoshihara

    18th International Zebrafish Conference　2024/08/18

  9. メダカとゼブラフィッシュを使った求愛行動の研究 Invited

    梶山十和子

    東北大学オープンキャンパス2024 サイエンス・アンバサダーと考える 研究者って何？　2024/07/30

  10. Publication of Gene Expression Atlas in the Adult Zebrafish Brain Invited

    OLSP Workshop 2024　2024/06/17

  11. Interspecies comparison of brains using small fishes

    2023/10

  12. Publication of Gene Expression Atlas in the Adult Zebrafish Brain Invited

    2023/06/15

  13. ゼブラフィッシュ脳内の 神経ペプチド発現アトラス /研究者の出産育児ガイド Invited

    梶山十和子

    第46回日本比較内分泌学会　2022/10/28

  14. Neuropeptide expression atlas in the adult zebrafish hypothalamus – definition of subnuclei and comparison with mammals –

    Towako Kajiyama, Yoshihiro Yoshihara

    Neuro2022　2022/06/30

  15. A Comprehensive Map of Neuropeptide Expressions in the Adult Zebrafish Brain

    Towako Hiraki-Kajiyama, Yoshihiro Yoshihara

    Neuro2019　2019/07/26

  16. Small fish for neuroscientific research

    Towako Hiraki-Kajiyama

    JINISM Lecture Series　2019/06/05

  17. A comprehensive expression map of neuropeptides in the adult zebrafish brain International-presentation

    Towako Hiraki-Kajiyama, Yoshihiro Yoshihara

    2018/08/25

  18. Female-specific expression of neuropeptide b and its role in reproductive behavior. International-presentation Invited

    Towako Hiraki-Kajiyama, Kataaki Okubo

    8th Congress of the Asia and Oceania Society for Comparative Endocrinology　2016/06/21

  19. Female-specific expression of neuropeptide B in the medaka brain International-presentation

    Towako Hiraki, Kiyoshi Nakasone, Junpei Yamashita, Kataaki Okubo

    10th International Symposium on Reproductive Physiology of Fish　2014/06

  20. Analysis of female-specific npb expression in the medaka brain International-presentation

    Towako Hiraki-Kajiyama, Yukika Kawabata, Kataaki Okubo

    20th Japanese Medaka and Zebrafish Meeting　2014

  21. Sex-dependent expression of estrogen and androgen receptor genes in the medaka brain International-presentation

    Towako Hiraki, Kataaki Okubo

    9th International Symposium on Reproductive Physiology of Fish　2011/08/09

  22. メダカの脳におけるエストロゲン受容体の発現の性差

    平木十和子, 妻木孝泰, 大久保範聡

    日本水産学会春季大会　2011/03

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Research Projects 4

  1. 性フェロモンにより誘起される生殖内分泌・性行動の神経回路解明

    梶山 十和子

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 若手研究

    Category: 若手研究

    Institution: 国立研究開発法人理化学研究所

    2019/04/01 - 2024/03/31

    More details Close

    本研究は性フェロモンのがどのような神経回路を介して内分泌や行動を制御しているのかを明らかにすることを目的としている。本年度は、研究実施計画に基づき以下のように研究を行った （１）内分泌・行動の変化の同定 性フェロモンの嗅覚刺激によりどのような内分泌・行動の変化がもたらされるのかを明らかにするために、ゼブラフィッシュの性フェロモンであると考えられる17α,20β-ジヒドロキシ-4-プレグネン-3-オン（17,20β-PS）の嗅覚受容体のノックアウトゼブラフィッシュの作製を進めた。本年度はターゲットとする嗅覚受容体のダブルノックアウトフィッシュ、シングルノックアウトフィッシュをそれぞれ作製し、交配・ジェノタイピングにより実験に使用する個体数の確保を行った。 <BR> （２）神経回路の解明 脳内で広くカルシウムインジケーターを発現するトランスジェニックフィッシュの作製を進め、実験に使用できるよう複数系統を準備した。また、性フェロモンの刺激により活性化するニューロン群のマーカー遺伝子を探すためのゼブラフィッシュの神経ペプチド発現アトラスの構築を進めた。本年は40種類のプローブを用い、in situ hybridizationを行った。また、その結果をもとにゼブラフィッシュの視床下部における神経亜核の定義を行った。さらに、結果をもとにゼブラフィッシュの脳とマウスの視床下部における神経ペプチド発現パターンの比較を行い、神経核同士の相同性を調べた。これらの結果をまとめた論文の執筆及びデータをリポジトリにアップロードする準備を行った。

  2. Molecular, cellular and circuit mechanisms underlying olfactory memory dynamism in zebrafish

    Yoshihara Yoshihiro, MIYASAKA Nobuhiko, KOIDE Tetsuya, HIRAKI Towako, WAKISAKA Noriko, MASUDA Miwa, YABUKI Yoichi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    Institution: Institute of Physical and Chemical Research

    2013/06/28 - 2018/03/31

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    In this study, we investigated molecular, cellular and circuit mechanisms underlying spatial and temporal dynamism of olfactory memory by using zebrafish as a model organism. First, we identified the four olfactory centers in the zebrafish forebrain (ventral telencephalon, posterior telencephalon, right habenula, posterit tuberculum) where odor information is conveyed from the mitral cells in the olfactory bulb. Next, we analyzed neural mechanism for appetitive olfactory conditioning in which fish are memorized with a given odorant stimulus associated with food reward. Finally, we dissected two distinct olfactory neural circuits that mediate attractive responses to food odors (amino acids and nucleotides) or sex pheromone (prostaglandin F2a). These findings will shed light on elucidation of commonality and difference between the innate and learned behaviors of animals.

  3. Construction of functional map in the hypothalamus in response to olfactory input

    Kajiyama Towako

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Research Activity Start-up

    Category: Grant-in-Aid for Research Activity Start-up

    Institution: Institute of Physical and Chemical Research

    2015/08/28 - 2017/03/31

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    The aim of this research is to elucidate (1) the neurons in the hypothalamus activated by olfactory input and (2) the change in the internal state caused by these neurons, using zebrafish as a model. For each aim, following result was obtained. (1) I searched for a transgenic line that can be used for calcium imaging. 4 lines were tried but no response was observed. Therefore 4 other lines are now under investigation. Neurons activated by olfactory input were identified by in situ hybridization. (2) Atlas of neuropeptide expression in the hypothalamus was constructed. Using this atlas, the neuropeptide expressed in the neurons activated by olfactory input was identified. I also produced transgenic fish lines and knockout fish lines for monitoring the change in the internal state.

  4. 魚類の性行動を制御する脳内メカニズムの解明

    梶山 十和子, 平木 十和子

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 特別研究員奨励費

    Category: 特別研究員奨励費

    Institution: 東京大学

    2012/04/01 - 2015/03/31

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    前年度に引き続き、メダカの脳内で性行動を支配するとされる領域でメスのみで発現する神経ペプチドNPBに着目して研究を進めた。 ①メス特異的なNPBの発現をもたらす調節機構：NPB遺伝子の上流にあるエストロゲン応答配列（ERE）をゲノム編集法により破壊したメダカを作出し、NPBの発現量を測定した。すると、NPBの発現がメスのみで減少していた。これにより、メス特異的なNPBの発現がエストロゲン受容体とNPB遺伝子上流に存在するERE様配列の結合による直接的なアップレギュレーションによってもたらされることが示された。 ②NPBの作用機序：メス特異的なNPBの作用場所を確かめるために、メダカの脊髄の最前部から最後部までの連続切片を作製し、NPBの受容体であるGPR8の発現をin situ hybridizationにより確かめた。すると、GPR8の発現は、脊髄の前角および、中心管よりも少し上のニューロンに前部から後部まで継続的にみられた。この結果から、NPBは交感神経系と運動神経系の両方に入力していることが示唆された。 ③NPBの性行動に対する役割：NPBノックアウトメダカの性行動の解析を行った。性行動を詳細に解析したが、有意な変化は見られなかった。そこで、NPBの新規パラロガス遺伝子NPCが補償的に働いてしまっている可能性を考え、NPBとNPCのダブルノックアウトメダカを作出した。また、NPB/NPCの受容体GPR8のノックアウトメダカも作出した。これらのノックアウトの性行動の解析により、NPB/NPCシグナルがメスの受け入れを抑制する働きを持つことを示す結果が得られた。

Teaching Experience 4

  1. 分子・細胞生物学特選科目Ⅰ　東北大学

  2. Biology Exercise I　Tohoku University

  3. Developmental Biology Practicum　Tohoku University

  4. Introductory Science Experiments　Tohoku University

Works 1

  1. Adult Zebrafish Brain Gene Expression Database

    Towako Hiraki-Kajiyama, Nobuhiko Miyasaka, Reiko Ando, Noriko Wakisaka, Hiroya Itoga, Shuichi Onami, Yoshihiro Yoshihara

    2023/03/31 - Present

    Type: Database

Social Activities 3

  1. 世界脳週間2024 東北大学サイエンスカフェ・合同研究室ツアー

    2025/03/20 -

  2. 匂いを感じる脳のしくみ ―魚の脳内を見てみよう―

    夏休み高校生理科教室

    2019/08 -

  3. Counselor for RIKEN open-house "Individual consultation for female junior high and high school students who wish to pursue a career in science".

    2019/04 -