Hotta, Kohji



Faculty of Science and Technology, Department of Biosciences and Informatics (Yagami)


Associate Professor

Related Websites

Academic Background 【 Display / hide

  • 1997.03

    Hokkaido University, Faculty of Science

    University, Graduated

  • 2002.03

    Kyoto University, Graduate School, Division of Natural Science

    Graduate School, Completed, Doctoral course

Academic Degrees 【 Display / hide

  • PhD, Kyoto University, Coursework, 2002.03


Research Areas 【 Display / hide

  • Developmental biology (Developmental Biology)

  • Morphology/Structure

  • Biophysics

Research Keywords 【 Display / hide

  • bioimaging

  • tunicate

  • mechanobiology

  • evodev

Research Themes 【 Display / hide

  • 尾芽胚の曲がりを支える3D形態ロジック, 


  • Logic of the Elongation of Tailbud in Chordates, 


  • quantitative analysis of morphogenesis by whole-animal 4D imaging, 


     View Summary

    Tailbud feature binds various chordates into one common group because all chordates have tails at larval stage. In this study, to understand a comprehensive anatomy of tailbud embryo at single-cell-level, we reconstructed three-dimensional computer model from confocal image stacks of Ciona tailbud embryo (stage 22, 10.9 hpf at 18 °C) by using Tassy’s method (2006). As a result, we characterized unique cell arrangement in each tissue and revealed that the tailbud embryo consists of 1583 cells.

  • Quantitative Analysis of Brain Vesicle Formation by 4D imaging, 


     View Summary

    Purpose of the Research Project

    Different region of central nervous system, fore brain, mid brain, hind brain and spinal cord originates from one neural tube at organogenesis period. Defects of neural tube formation cause severe diseases, including anencephaly and spina bifida. While understanding of differentiation at the molecular level has been deepened, the molecular mechanism of the morphogenesis of neural tubes at different regions remains to be clarified.

    One of chordate, ascidian a

  • Robustness and Polymorphism of Individual Morphology in the Phylotypic Stage, 



Papers 【 Display / hide

  • Spatiotemporal dynamics of single cell stiffness in the early developing ascidian chordate embryo

    Fujii Y., Koizumi W.C., Imai T., Yokobori M., Matsuo T., Oka K., Hotta K., Okajima T.

    Communications Biology (Communications Biology)  4 ( 1 )  2021.12

     View Summary

    During the developmental processes of embryos, cells undergo massive deformation and division that are regulated by mechanical cues. However, little is known about how embryonic cells change their mechanical properties during different cleavage stages. Here, using atomic force microscopy, we investigated the stiffness of cells in ascidian embryos from the fertilised egg to the stage before gastrulation. In both animal and vegetal hemispheres, we observed a Rho kinase (ROCK)-independent cell stiffening that the cell stiffness exhibited a remarkable increase at the timing of cell division where cortical actin filaments were organized. Furthermore, in the vegetal hemisphere, we observed another mechanical behaviour, i.e., a ROCK-associated cell stiffening, which was retained even after cell division or occurred without division and propagated sequentially toward adjacent cells, displaying a characteristic cell-to-cell mechanical variation. The results indicate that the mechanical properties of embryonic cells are regulated at the single cell level in different germ layers.

  • Peripheral-neuron-like properties of differentiated human dental pulp stem cells (hDPSCs)

    Arimura Y., Shindo Y., Yamanaka R., Mochizuki M., Hotta K., Nakahara T., Ito E., Yoshioka T., Oka K.

    PLoS ONE (PLoS ONE)  16 ( 5 May )  2021.05

     View Summary

    Elucidating the mechanisms underlying human pain sensation requires the establishment of an in vitro model of pain reception comprising human cells expressing pain-sensing receptors and function properly as neurons. Human dental pulp stem cells (hDPSCs) are mesenchymal stem cells and a promising candidate for producing human neuronal cells, however, the functional properties of differentiated hDPSCs have not yet been fully characterized. In this study, we demonstrated neuronal differentiation of hDPSCs via both their expression of neuronal marker proteins and their neuronal function examined using Ca2+ imaging. Moreover, to confirm the ability of nociception, Ca2+ responses in differentiated hDPSCs were compared to those of rat dorsal root ganglion (DRG) neurons. Those cells showed similar responses to glutamate, ATP and agonists of transient receptor potential (TRP) channels. Since TRP channels are implicated in nociception, differentiated hDPSCs provide a useful in vitro model of human peripheral neuron response to stimuli interpreted as pain.

  • High responsiveness of auditory neurons to specific combination of acoustic features in female songbirds

    Inda M., Hotta K., Oka K.

    European Journal of Neuroscience (European Journal of Neuroscience)  53 ( 5 ) 1412 - 1427 2021.03

    ISSN  0953816X

     View Summary

    Zebra finch (Taeniopygia guttata) is a songbird species in which males sing their unique songs to attract females who then select their preferred male. Acoustic features in the songs of individual males are important features for female auditory perception. While the male of this species is a classic model of vocal production, it has been little known about auditory processing in female. In the higher auditory brain regions, the caudomedial mesopallium (CMM) and nidopallium (NCM) contribute to female's sound recognition, we, therefore, extracted acoustic features that induce neural activities with high detection power on both regions in female finches. A multiple linear regression analysis revealed that neurons were sensitive to mean frequency and Wiener entropy. In addition, we performed an experiment with modified artificial songs and harmonic songs to directly investigate neural responsiveness for deriving further evidence for the contribution of these two acoustic features. Finally, we illustrated a specific ratio combining these two acoustic features that showed highest sensitivity to neural responsiveness, and we found that properties of sensitivity are different between CMM and NCM. Our results indicate that the mixture of the two acoustic features with the specific ratio is important in the higher auditory regions of female songbirds, and these two regions have differences in encoding for sensitivity to these acoustic features.

  • Two-Round Ca 2+ transient in papillae by mechanical stimulation induces metamorphosis in the ascidian Ciona intestinalis type A

    Wakai M.K., Nakamura M.J., Sawai S., Hotta K., Oka K.

    Proceedings of the Royal Society B: Biological Sciences (Proceedings of the Royal Society B: Biological Sciences)  288 ( 1945 )  2021.02

    ISSN  09628452

     View Summary

    Marine invertebrate larvae are known to begin metamorphosis in response to environmentally derived cues. However, little is known about the relationships between the perception of such cues and internal signalling for metamorphosis. To elucidate the mechanism underlying the initiation of metamorphosis in the ascidian, Ciona intestinalis type A (Ciona robusta), we artificially induced ascidian metamorphosis and investigated Ca 2+ dynamics from pre- to post-metamorphosis. Ca 2+ transients were observed and consisted of two temporally distinct phases with different durations before tail regression which is the early event of metamorphosis. In the first phase, Phase I, the Ca 2+ transient in the papillae (adhesive organ of the anterior trunk) was coupled with the Ca 2+ transient in dorsally localized cells and endoderm cells just after mechanical stimulation. The Ca 2+ transients in Phase I were also observed when applying only short stimulation. In the second phase, Phase II, the Ca 2+ transient in papillae was observed again and lasted for approximately 5-11 min just after the Ca 2+ transient in Phase I continued for a few minutes. The impaired papillae by Foxg-knockdown failed to induce the second Ca 2+ transient in Phase II and tail regression. In Phase II, a wave-like Ca 2+ propagation was also observed across the entire epidermis. Our results indicate that the papillae sense a mechanical cue and two-round Ca 2+ transients in papillae transmits the internal metamorphic signals to different tissues, which subsequently induces tail regression. Our study will help elucidate the internal mechanism of metamorphosis in marine invertebrate larvae in response to environmental cues.

  • Sexual and asexual development: two distinct programs producing the same tunicate

    Kowarsky M., Anselmi C., Hotta K., Burighel P., Zaniolo G., Caicci F., Rosental B., Neff N.F., Ishizuka K.J., Palmeri K.J., Okamoto J., Gordon T., Weissman I.L., Quake S.R., Manni L., Voskoboynik A.

    Cell Reports (Cell Reports)  34 ( 4 )  2021.01

     View Summary

    Colonial tunicates are the only chordate that possess two distinct developmental pathways to produce an adult body: either sexually through embryogenesis or asexually through a stem cell-mediated renewal termed blastogenesis. Using the colonial tunicate Botryllus schlosseri, we combine transcriptomics and microscopy to build an atlas of the molecular and morphological signatures at each developmental stage for both pathways. The general molecular profiles of these processes are largely distinct. However, the relative timing of organogenesis and ordering of tissue-specific gene expression are conserved. By comparing the developmental pathways of B. schlosseri with other chordates, we identify hundreds of putative transcription factors with conserved temporal expression. Our findings demonstrate that convergent morphology need not imply convergent molecular mechanisms but that it showcases the importance that tissue-specific stem cells and transcription factors play in producing the same mature body through different pathways.

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Papers, etc., Registered in KOARA 【 Display / hide

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Reviews, Commentaries, etc. 【 Display / hide

Presentations 【 Display / hide


    Ayelet Voskoboynik, Mark Kowarsky, Benyamin Rosental, Aaron M. Newman, Kohji Hotta, Katherine J. Ishizuka, Karla J. Palmeri, Norma F. Neff, Stephen R. Quake & Irving L. Weissman

    North America Comparative Immunology Workshop 2017, 2017.06

  • The complete annotation of Ciona development and anatomy: the larval and metamorphosis stages.

    Lucia Manni1, Delphine Dauga2 and Kohji Hotta

    the Italian Embryology Group Meeting, 2017.06, Oral Presentation(general)

  • Relationship between dynamics of cytoskeleton and cell stiffness in early ascidian embryo development.

    Imai T, Koizumi W, Fujii Y、Okajima T, Oka K, Hotta K

    The 22nd International Congress of Zoology, The 87th Meeting of The Zoological Society of Japan Joint Events in Okinawa, 2016.11

  • In vivo-Imaging Analysis of Calcium Transients in Early Development of Ascidian Embryo.

    Taichi Akahoshi, Kohji Hotta, Kotaro Oka

    The 22nd International Congress of Zoology, The 87th Meeting of The Zoological Society of Japan Joint Events in Okinawa (Okinawa) , 2016.11, Poster (general)

  • Morphometry of tailbud embryo for understanding mechanism of conserved chordate phylotypic embryo shape.

    Muraoka Hiromochi, Koizumi Wataru, Oka Kotaro, Hotta Kohji

    The 22nd International Congress of Zoology, The 87th Meeting of The Zoological Society of Japan Joint Events in Okinawa, 2016.11, Poster (general)

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Research Projects of Competitive Funds, etc. 【 Display / hide

  • Quantitative analysis of the mechanism of ascidian metamorphosis


    MEXT,JSPS, Grant-in-Aid for Scientific Research, 堀田 耕司, Grant-in-Aid for Scientific Research on Innovative Areas, Principal Investigator

  • Mechanism of shaping brain compartments


    Japan Society for the Promotion of Science (JSPS), Grant-in-Aid for Scientific Research, Kohji Hotta, Research grant, Principal Investigator

  • tail-curving mechanism of tailbud embryo


    Japan Society for the Promotion of Science (JSPS), Grant-in-Aid for Scientific Research, Kohji Hotta, Research grant, Principal Investigator

Awards 【 Display / hide

  • 武田科学財団 一般研究奨励

    HOTTA KOHJI, 2008.11, 脊索動物個体全体を用いた神経細胞ネットワークの網羅的解明

    Type of Award: Awards of Publisher, Newspaper Company and Foundation


Courses Taught 【 Display / hide











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Courses Previously Taught 【 Display / hide

  • biology course for beginner

    Keio University, 2018, Spring Semester, General education subject, Lecture, Within own faculty, 2h, 200people


  • basic biological course

    Keio University, 2018, Autumn Semester, Major subject, Laboratory work/practical work/exercise

  • developmental biology

    Keio University, 2018, Autumn Semester, Major subject, Lecture, Within own faculty, 30people

  • 生命情報実験

    Keio University, 2018, Autumn Semester, Major subject, Laboratory work/practical work/exercise, Within own faculty, 40people

  • cell biology III

    Keio University, 2018, Autumn Semester, Major subject, Lecture, Within own faculty, 40people

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Social Activities 【 Display / hide

  • International Tunicate Information System Meeting


Memberships in Academic Societies 【 Display / hide

  • Genetic Meeting in Japan

  • Zoological Sciety of Japan

  • Jananese Society of Developmental Biology

  • Society of Evolutionary Studies, Japan

  • The Molecular Biology Society of Japan


Committee Experiences 【 Display / hide

  • 2010.04

    International Tunicate Information System Meeting Organizing Committee, International Tunicate Information System Meeting