Shuntaro Izawa

Affiliation：Institute of Medicine/International Institute for Integrative Sleep Medicine, University of Tsukuba

Research Title

Neuroscience

Sleep regulation by neuroendocrinology. How do hormones affect the brain and behavior?

01 Research Summary

The discovery of orexin has had a profound impact on society, advancing our understanding of narcolepsy and leading to the development of orexin receptor antagonists for the treatment of insomnia. Neurons in the hypothalamus—a deep brain region—produce not only orexin but also a variety of neuropeptides, including melanin-concentrating hormone (MCH) and nociceptin, and play essential roles in regulating physiological functions such as sleep–wake states and energy metabolism. Recent studies have further revealed that some hypothalamic neurons are modulated by circulating hormones derived from peripheral organs, such as insulin and leptin. In our laboratory, we aim to elucidate how such hormone-mediated endocrine systems regulate sleep and other vital functions at the level of the whole organism, rather than focusing solely on the brain. To achieve this, we integrate cutting-edge neuroscience techniques with careful and systematic behavioral analyses in animal models.

Link	Izawa Laboratory(Under preparation)

02 Major achievements

Izawa S, Fusca D, Jiang H, Heilinger C, Hausen AC, Wunderlich FT, Steuernagel L, Kloppenburg P, Brüning JC. Orexin/hypocretin receptor 2 signaling in MCH neurons regulates REM sleep and insulin sensitivity. Cell Reports, 44(2):115277 (2025) 2

Izawa S, Yoneshiro T, Kondoh K, Nakagiri S, Okamatsu-Ogura Y, Terao A, Minokoshi Y, Yamanaka A, Kimura K. Melanin-concentrating hormone-producing neurons in the hypothalamus regulate brown adipose tissue and thus contribute to energy expenditure. The Journal of Physiology, 600(4):815-827 (2022)

Izawa S, Chowdhury S, Miyazaki T, Mukai Y, Ono D, Inoue R, Ohmura Y, Mizoguchi H, Kimura K, Yoshioka M, Terao A, Kilduff T, Yamanaka A. REM sleep–active MCH neurons are involved in forgetting hippocampus-dependent memories. Science, 365(6459): 1308-1313 (2019)

03 Education/Academic background and major awards

Education/Academic background

2016	Doctor of Veterinary Medicine (D.V.M), Hokkaido University, Japan
2020	Doctor of Philosophy (Ph.D), Graduate School of Medicine, Nagoya University, Japan
2021 - 2026	Postdoctoral Fellow, Max Planck Institute for Metabolism Research, Germany
2023 - 2026	Project Leader, Excellence Cluster for Aging Research (CECAD) /University of Cologne, Germany
2026 - Present	Associate Professor, Faculty of Medicine, University of Tsukuba/ Principal Investigator, International Institute for Integrative Sleep Medicine, University of Tsukuba

Awards

2017	Young lnvestigator Award, Japan Neuroendocrine Society
2020	Outstanding graduate student award, Nagoya University
2020	Toshihiko Tokizane Memorial Award for Excellent Graduate Study in Neuroscience, Japan Neuroscience Society
2021	Ikushi Prize, Japan Society for the Promotion of Science
2023	ECAD Career-Promoting Grant Award for Senior Postdoc

Why did you become a scientist?

Coincidence

While conducting my undergraduate thesis research, I came across some unexpected data that sparked my curiosity and compelled me to investigate it further. This experience caused me to change my career path just before graduating. During my PhD and postdoctoral period, I have continued to encounter new scientific questions that I am driven to solve. I find great joy in advancing each project, and it would be highly fulfilling if my work ultimately contributes to a better understanding of fundamental biological phenomena and to developing treatments for diseases.

What are the characteristics of your lab?

Diversity

I have mainly focused on melanin-concentrating hormone (MCH), extending beyond sleep to areas such as memory and metabolism. As well as investigating the mechanisms of sleep itself, our aim is to understand the interactions between sleep and other vital physiological functions. With a background in veterinary medicine, our studies cover a variety of mammalian species, not limited to mice. If you are interested in interdisciplinary research on sleep and neuroendocrinology, please contact us.

What are you most interested in lately

Kendo

When I was an undergraduate, I was so absorbed in it that I had to repeat a year. I also became deeply involved in it during my time in Germany, and suffered a serious injury - a complete rupture of the Achilles tendon. Going forward, I hope to enjoy it in moderation.

Core Group

University of Tsukuba Collaborative Research Group

Administrative Department