School of Veterinary Medicine

Hori Tatsuya

  (堀 達也)

Profile Information

Affiliation
Professor, Faculty of Veterinary Science, School of Veterinary Medicine, Department of Reproduction, Nippon Veterinary and Life Science University
Degree
Veterinary Medicine

J-GLOBAL ID
200901033112844779
researchmap Member ID
1000192390

Papers

 106
  • Keiko Yamamoto, Nobuyuki Kashiwagi, Mika Otsuka, Tatsuya Hori
    The Journal of veterinary medical science, Jun 27, 2024  Peer-reviewed
    In this study, we examined the usefulness of a simpler and more feasible method for determining the optimal timing of artificial insemination and the conditions for its success in six female common bottlenose dolphins. Pregnancy was successfully achieved in five dolphins by performing intrauterine insemination, using chilled semen stored for less than 3 days or frozen semen within 24 hr of exhibiting a peak serum estradiol (E2) level of 100 pg/mL or higher or on the day with a serum E2 level of approximately 100 pg/mL, measured with a simple measuring device. We concluded that the determining the optimal timing of intrauterine insemination by measuring serum E2 levels is a simpler and more useful method compared with the conventional approach.
  • Masanori Kobayashi, Moe Onozawa, Shiho Watanabe, Tomokazu Nagashima, Kyoichi Tamura, Yoshiaki Kubo, Akiko Ikeda, Kazuhiko Ochiai, Masaki Michishita, Makoto Bonkobara, Masato Kobayashi, Tatsuya Hori, Eiichi Kawakami
    Veterinary and comparative oncology, Feb 6, 2023  Peer-reviewed
    Canine prostate cancer (cPCa) is a malignant neoplasm with no effective therapy. The BRAF V595E mutation, corresponding to the human BRAF V600E mutation, is found frequently in cPCa. Activating BRAF mutations are recognized as oncogenic drivers, and blockade of MAPK/ERK phosphorylation may be an effective therapeutic target against BRAF-mutated tumors. The aim of this study was to establish a novel cPCa cell line and to clarify the antitumor effects of MEK inhibitors on cPCa in vitro and in vivo. We established the novel CHP-2 cPCa cell line that was derived from the prostatic tissue of a cPCa patient. Sequencing of the canine BRAF gene in two cPCa cell lines revealed the presence of the BRAF V595E mutation. MEK inhibitors (trametinib, cobimetinib, and mirdametinib) strongly suppressed cell proliferation in vitro, and trametinib showed the highest efficacy against cPCa cells with minimal cytotoxicity to non-cancer COPK cells. Furthermore, we orally administered 0.3 or 1.0 mg/kg trametinib to CHP-2 xenografted mice and examined its antitumor effects in vivo. Trametinib reduced tumor volume, decreased phosphorylated ERK levels, and lowered Ki-67 expression in xenografts in a dose-dependent manner. Although no clear adverse events were observed with administration, trametinib-treated xenografts showed osteogenesis that was independent of dosage. Our results indicate that trametinib induces cell cycle arrest by inhibiting ERK activation, resulting in cPCa tumor regression in a dose-dependent manner. MEK inhibitors, in addition to BRAF inhibitors, may be a targeted agent option for cPCa with the BRAF V595E mutation. This article is protected by copyright. All rights reserved.
  • Masato Kobayashi, Honami Sekine, Yushi Ogawa, Shin Toyama, Yuki Komukai, Moto Nakamura, Ryusuke Mitanda, Marina Hayashi, Masanori Kobayashi, Tatsuya Hori
    Journal of Reproductive Immunology, 155 103778-103778, Feb, 2023  Peer-reviewed
    Tolerance towards fetal alloantigens in the maternal immune system is essential for maintaining pregnancy. Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells characterized by their ability to suppress immune activity and maintain maternal-fetal immune tolerance. However, the mechanisms underlying MDSC induction have not been elucidated. Herein, we investigated the myeloid-derived suppressor cells (MDSCs) in the peripheral blood of pregnant canines and its induction mechanism. By analyzing the concentration of MDSCs in the peripheral blood of pregnant canines, elevation of MDSCs has been observed during pregnancy. In addition, MDSCs from pregnant canines inhibit T cell activation. These results suggest that the elevated MDSCs in canine pregnancy may contribute to reduces maternal immune activity. To clarify the cause of MDSCs elevation in canine pregnancy, we analyzed the relationship between pregnancy-related hormones (estradiol, progesterone, and relaxin) and MDSCs. Serum relaxin levels, but not estradiol and progesterone, were correlated with the ratio of monocyte MDSCs. Additionally, relaxin induced monocytic MDSCs as well as inhibited T cell activation in vitro. Therefore, relaxin contributes to the elevation of monocytic MDSCs in the peripheral blood of pregnant canines. Our findings highlight the novel role of relaxin in pregnancy and contribute to a better understanding of maternal-fetal immune tolerance.
  • Akiko Ikeda, Masanori Kobayashi, Tatsuya Hori, Masaki Michishita, Masato Kobayashi, Eiichi Kawakami
    American Journal of Animal and Veterinary Sciences, 18(1) 47-51, Jan 1, 2023  Peer-reviewed
  • Tatsuya Hori, Hideo Tajima, Shinichi Sasaki, Mizuki Karasawa, Madoka Yoshizawa, Takuya Kuribara, Hidemasa Hori, Fujio Yamamoto, Etsuo Narushima, Kiyoshi Nagai, Kazuaki Nippashi, Yurie Sataka, Masato Kobayashi, Masanori Kobayashi, Toshihiko Tsutsui
    The Journal of veterinary medical science, Nov 28, 2022  Peer-reviewed
    In this study, cauda epididymal sperm were collected from Amur leopard cats with various causes of death as well as Tsushima leopard cats that underwent castration surgery, and sperm quality was compared with that in domestic cats. A sufficient number of sperm similar to those in domestic cats could be collected from the cauda epididymis of Amur leopard cats. However, in old leopard cats, no or very few cauda epididymal sperm were recovered, although there were no differences in sperm motility and sperm abnormality. There were no significant differences in sperm quality immediately after collection and after freezing-thawing of cauda epididymal sperm compared with corresponding estimates in domestic cats.

Misc.

 84

Books and Other Publications

 14
  • 辻本 元, 堀 達也
    インターズー, 2015
  • 石田卓夫, 堀 達也 (Role: Contributor, 子宮蓄膿症における治療法の選択 (pp.121-129))
    緑書房, 2015
  • 村田浩一, 楠田哲士, 堀 達也 (Role: Joint translator, 雄の繁殖:評価、治療、生殖補助および生殖コントロール(pp.509-529))
    文永堂出版, 2014
  • 小笠 晃, 堀 達也 (Role: Contributor, 生殖器の発生と分化、雌性生殖器、卵子、雌犬・雌猫の繁殖障害(pp.1-2, 23-35, 301-308))
    朝倉書店, 2014
  • 辻本 元, 堀 達也
    インターズー, 2012

Presentations

 112

Professional Memberships

 2

Research Projects

 9