Report of the 5 th Academic Symposium “ Aiming to Overcome Intractable Itch ” in Juntendo University

grant of Education, Culture, Sports, Science and Technology (MEXT) of Japan. Since 2013, we have been focusing on intractable itch supported by Strategic Research Foundation Grant-aided Project for Private Universities from MEXT. We have been conducting research on elucidating the pathogenesis of intractable itch and developing preventive and therapeutic methods, and the results of our research have been highly evaluated both in Japan and overseas. After the end of the above support project, Asiaʼs first itch research center, Juntendo Itch Research Center (JIRC), was established at our institute to promote research in this field and to return the results of our research to society. In addition, our institute has held four academic symposiums about“Aiming to overcome intractable itch”since 2014 in order to develop itch research in Japan. The 5 th Symposium, which was the first since JIRC was established, was held on December 7, 2019. In this“Whatʼs New from Juntendo University, Tokyo”, we report selected aspects of the 5 th Symposium and advances in the field of itch research.


Background
Intractable itch, which is resistant to conventional treatments, causes sleep disturbance and psychological stress (depression, anxiety, and even suicidal feelings), which lead to poor performance in school or at work and reduce the quality of life (QOL). Such reduction of QOL diminishes motivation to pursue an industrious life and social activities, affecting socioeconomic activity 1) 2) . Based on this background, several itch research centers were established worldwide and began to focus on revealing the mechanism of intractable itch, aiming for its prevention and treatment.
The Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine (founding director; CEO Hideoki Ogawa, M.D., Ph.D.), was founded in 2002, supported by a grant of High-Tech Research Center Project for Private Universities: matching fund subsidy from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. Currently, Prof. Kenji Takamori (M.D., Ph.D.), a director of Institute for Environmental and Gender Specific Medicine in Juntendo University, is engaged in the themes, 1) elucidation of pathogenic mechanisms of allergic diseases, autoimmune diseases and cancer, in which environmental and genetic factors are intricately intertwined, and 2) improvement of QOL in patients with those diseases.
Since 2013, Prof. Takamori and collaborators have been focusing on intractable itch supported by Strategic Research Foundation Grant-aided Project for Private Universities from MEXT (Grant number S1311011). So far, we have discovered some neural cells or mediators involved in the pathogenic process of diseases with intractable itch, which should be targets for therapeutic strategies.
To promote continued research in this field beyond the above-mentioned support, we established Juntendo Itch Research Center (JIRC) on the 1 st of August, 2019, which is a center associated with our institute. In this research center, building on the basis of our previous findings, we are aiming to elucidate the molecular and cellular basis of intractable itch and develop medical care including an evaluation system, while educating young researchers and graduate students in both basic science and clinical fields. This research center expects to establish a framework of translational research to develop new treatments for intractable itch, improving QOL and socioeconomic activity.
To further advance this research area, which remains ongoing, we have held symposium regarding itch research since 2014 at Juntendo University 3) 4) . In December, 2019, we held the 5 th Academic Symposium"Aiming to overcome intractable itch"at Juntendo University. In brief, we here report selected aspects of this symposium.

Short report
On 7 th December, 2019, the 5 th symposium was held in the Century Tower at Juntendo University ( Figure-1). There were 113 attendees (50 from Juntendo University and 63 from elsewhere) at the symposium which included nine lectures by leading scientists including itch researchers (Table-1).
In his opening speech, Dean Nobutaka Hattori, Faculty of Medicine and Graduate School of Medicine, Juntendo University explained the worldwide importance of the itch research project, and that achievements of this organization are expected to contribute to improvement in patients suffering from intractable itch. Finally, he told us he expected us to actively exchange views in this symposium (Figure-2).
In the Introduction, Director Kenji Takamori of Juntendo Itch Research Center (JIRC), Institute for Environment and Gender-Specific Medicine, Juntendo University described the background of establishment of the JIRC. He talked about the aims and members of the JIRC and emphasized the importance of elucidating the pathogenic mechanisms and developing preventive and therapeutic methods to treat intractable itch.
Prof. Ryusuke Kakigi of the National Institute for Physiological Sciences described the central mechanism of itch in humans using functional brain imaging.
Prof. Hiroshi Matsuda of the Division of Animal Life Science, Institute of Agriculture, Tokyo University of Agriculture and Technology presented his research on establishment of an atopic dermatitis model NC/Tnd mouse and explained its usefulness.
Associate Prof. Toshiro Takai of Atopy Research Center, Juntendo University Graduate School of Medicine overviewed his research area regarding relationships between protease antigen and allergy.
Assistant Prof. Miho Shiratori-Hayashi of Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University introduced us to the knowledge that her research group recently had discovered itch-related molecules such as lipocalin-2 (LCN2) and P2X3 receptor. She also discussed the roles of glial cells in the processing of itch signalling.
Dr. Chisa Nakashima of Department of Dermatology, Kyoto University Graduate School of Medicine presented research detailing the involvement of neuro-immune communication in the pathological mechanism of allergic skin diseases such as atopic dermatitis and contact dermatitis.
Prof. Takehiko Yokomizo of the Department of Prof. Yoshinori Fukui of Division of Immunogenetics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University made a presentation regarding the molecular basis of IL-31-induced itch from skin to spinal cord.
Prof. Yasuyuki Igarashi of Hokkaido University commented on this symposium and JIRC (Figure-3). First, he praised Prof. Takamori for establishing Asiaʼs first wonderful itch research center. Then he provided his comments and expectations that itch research will be conducted jointly between Juntendo University and Kyushu University to help people suffering from itch throughout the country. He also commented that since young researchers are studying itch and joining this field, this research area will continue to develop in the future.
In his closing speech, Prof. Takashi Sakurai of the Department of Cellular and Molecular Pharmacology, Juntendo University commented that all of the presentations had been excellent and had given us new insights regarding itch research. He said he hopes that itch research will continue to grow around this JIRC.

Conflicts of interest
The authors declare they have no conflicts of interest.