Analysis of the relationship between the peripheral circadian clock and hibernation in a hibernating mammal

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06746
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44050:Animal physiological chemistry, physiology and behavioral biology-related
• Research Institution: Kitasato University
• Principal Investigator: Takamatsu Nobuhiko 北里大学, 理学部, 教授 (40206876)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 転写制御 / 概日リズム / 末梢時計 / Per2 / HSF1

Outline of Final Research Achievements

In mammals, various physiological processes such as sleep-wake rhythms, body temperature fluctuations, and metabolism are regulated by the circadian clock. In this study, we analyzed the expression of clock genes in the liver of chipmunks to investigate the relationship between peripheral circadian clock and hibernation in a hibernating mammal. In the hibernation season, Per2 mRNA was transiently increased by HSF1, which was activated by elevated body temperature during interbout arousal, and showed periodic fluctuations in the torpor-arousal cycle, but no periodic fluctuations were observed in Bmal1 mRNA, suggesting that the peripheral circadian clock was not functioning. Therefore, it was suggested that in the hibernation season, gene expression necessary for hibernation may be carried out by the formation of a new gene network.

Free Research Field

冬眠

Academic Significance and Societal Importance of the Research Achievements

冬眠哺乳動物は，深冬眠中には，数日間-数週間，数℃の低体温で，丸まった固定した姿勢で過ごす。冬眠期の深冬眠-中途覚醒サイクルでは心拍数が大幅に変動するため，虚血-再灌流のような状態に晒される。また冬眠中のエネルギー源として脂肪を蓄積し，体重を大幅に増加させる種もいる。これらの観察から，冬眠哺乳動物は低体温症，廃用性筋萎縮，虚血-再灌流による細胞へのダメージや糖尿病に対して強い耐性を有していると考えられており，その分子基盤の解明は医療にも有用な知見をもたらすものと期待されている。本研究により，冬眠期に構築される遺伝子ネットワークの解析は，そのような分子基盤の解明に繋がることが期待される。