Living in Space
Integral Understanding of life-regulation mechanism from "SPACE"

The immunological memory under the alteration of gravity as an extreme stress ―Regulation and failure of its establishment, maintenance and re-activation― – Publicly Invited Research 2018－2019

1. A01 Ogura
2. A01 H. Takahashi
3. A01 S. Takahashi
4. A01 Michiue
5. A01 Hinoi
6. A01 Tsumoto
7. A01 Nikawa
8. A01 Chatani
9. A01 Kawakami
10. A01 Akiyama
11. A01 Tomita

1. A02 Shinohara
2. A02 Mieda
3. A02 Maekawa
4. A02 Abe
5. A02 Ohgami
6. A02 Kawano
7. A02 Takano

1. A03 Suzuki
2. A03 Nakamura
3. A03 Harada
4. A03 Kobayashi
5. A03 Miyamoto
6. A03 Funayama
7. A03 Kakinuma

1. B01 Lazarus
2. B01 Kato
3. B01 Kunieda
4. B01 Kitaya
5. B01 Sawano

Research Subject	The immunological memory under the alteration of gravity as an extreme stress ―Regulation and failure of its establishment, maintenance and re-activation―
Research Group Leader	Yoichi Maekawa Professor, Gifu University Graduate School of Medicine Domain Leader, G-CHAIN, Gifu University Website http://www.med.gifu-u.ac.jp/labo/parasite/index.html (*Written in Japanese)
Research Collaborator(s)	Hironobu Morita Professor, Gifu University Graduate School of Medicine Yasuhiro Takashima Associate Professor, Graduate School of Applied Biological Sciences, Gifu University

The immune system is known to be affected by extreme stress such as microgravity in a spacecraft. The severe effects on the immune system are directly linked to such immunological disorders as elevated susceptibility to infections, allergies, autoimmune diseases and cancer. Although the immune system is believed have the plasticity needed to maintain its homeostasis, a comprehensive understanding of its mechanisms is still necessary.

We have already found that the development and/or maintenance of subpopulation of memory CD4⁺ T cells is affected under hypergravity. This alteration is not cancelled by the vestibular lesion (VL). We also found that increased cell number of spleen in the mice chronically infected with Toxoplasma gondii is reduced under hypergravity and this reduction is cancelled by VL. These findings indicate that the immune system might have been affected both directly and indirectly by the gravity change. When we investigated the molecular alteration occurred in the immune system under the hypergravity by DNA microarray, we identified that IL-6 is significantly affected in the draining lymph node of mice immunized with model antigen.

In this research, we integrate our previous findings and address at molecular level the issue of how the immunological memory, in particular the establishment, maintenance and re-activation of memory T cells, is affected under the stressful environment such as space flight. From our approach, we would like to find a novel mechanism that regulate the immune system, as well as strategies for living in space without any immunological failure.