Title of Research:
23-6-03

A Validation Study for approval of AOP475 that proposes a New
Approach Method for OECD TG on Neurotoxicity andDevelopmental Neurotoxicity.
Principal Investigator:
Yuko Sekino, PhD (Project Professor, The University of Tokyo, Graduate School of Agriculturaland Life Sciences, Department of Veterinary Pathophysiology and Animal Health) 1-1-1 Yayoi,
Bunkyo-ku, Tokyo 113-8657, Japan (tel)+81-3-5841-5390, (e-mail) yukos@g.ecc.u-tokyo.ac.jp
Collaborators
Izuo Tsutsui, PhD (Researcher, The University of Tokyo, Graduate School of Agricultural and Life
Sciences, Department of Veterinary Pathophysiology and Animal Health) 1-1-1 Yayoi, Bunkyo-ku,
Tokyo 113-8657, Japan (tel)+81-3-5841-5390, (e-mail) iztsutsui@g.ecc.u-tokyo.ac.jp
Yonehiro Kanemura, MD, PhD (Director, Department of Biomedical Research and Innovation
Institute for Clinical Research, National Hospital Organization Osaka National Hospital) 2-1-14
Hoenzaka, Chuo-ku, Osaka 540-0006, Japan (tel)+ 81-6-6942-1331, (e-mail)kanemura.yonehiro.hk@mail.hosp.go.jp
Shihori Tanabe, PhD (Senior Researcher, Division of Risk Assessment, Center for Biological
Safety and Research, National Institute of Health Sciences) 3-25-26 Tonomachi, Kawasaki-ku,Kawasaki City, Kanagawa, 210-9501, Japan (tel)+81-44-270-6600, (e-mail) stanabe@nihs.go.jp
Sachiko Yoshida, PhD (Toyohashi University of Technology, Center for Diversity and Inclusion,
Appointed to Dept. Applied Chemistry & Life Science) 1-1 Hibarigaoka, Tenpaku-cho, Toyohasicity, Aichi, 441-8580, Japan (tel) +81-532-８1-5106, (e-mail) syoshida@tut.jp
Summary of Research:
The aim of this research is to finalize the AOPwiki entry for AOP475 proposed to the OECD.
During this term, we participated in AOP coaching and incorporated intracellular Ca2+ overload,dendritic spine abnormality, and decreased neuronal network function into the Key Event (KE).
We are currently gathering literature to link KE1 to KE4 and examining papers to connect KE4 toKE6. Experiments utilizing frozen rat neurons for primary culture and live rats were carried out todemonstrate the relationship between risk compounds of Impairment of Learning and Memory(AO) and Loss of Drebrin (KE3). Nine compounds were administered to cultured neurons, fixed,and immunocytochemically stained for drebrin and MAP2. Neuronal cell death was observed after
1 and 7 days of treatment with Compound A, but not at 1 hour. However, the number of highintensity drebrin clusters was significantly reduced even at 1 hr. After a single oral dose ofCompound B and Compound C to pregnant rats on gestation day 15, changes in drebrin
expression were detected in the hippocampus and neocortex of the offspring (6 weeks). Changes
in localization and expression of drebrin are useful indicators for risk assessment of compounds.
Timeline:
March 1, 2023 –Topics:
Oral presentation at LRI research report meeting (25th Aug. 2023)
Publications:[Original paper] Lin Waka, Shiomoto Shusaku, Yamada Saki, Watanabe Hikaru, Kawashima
Yudai, Eguchi Yuichi, Muramatsu Koichi, Sekino Yuko “Dendritic spine formation and synapse
maturation in transcription factor-induced human iPSC-derived neurons.” iScience. 26(4):106285,
2023, and another publication[Conference presentation] Yuko Sekino, Izuo Tsutsui, Tomoaki Shirao, Shihori Tanabe“Impairment of learning and memory via loss of drebrin from dendritic spines of neurons.” The
97th Annual Meeting of the Japanese Pharmacological Society, Kobe, December 2023, and fiveother publications.
【Lecture】Yuko Sekino, "Actin cytoskeleton in synapses controls memory," The 46th Annual
Meeting of the Japanese Neuroscience Society, Luncheon Seminar, Sendai, August 1, 2023.