Naked mole-rat brown fat thermogenesis is diminished during hypoxia through a rapid decrease in UCP1
Hang Cheng, Rajaa Sebaa, Nikita Malholtra, Baptiste Lacoste, Ziyad El Hankouri, Alexia Kirby, Nigel C. Bennett, Barry van Jaarsveld, Daniel W. Hart, Glenn J. Tattersall, Mary‐Ellen Harper, Matthew E. Pamenter
Abstract
Abstract Naked mole-rats are among the most hypoxia-tolerant mammals. During hypoxia, their body temperature ( T b ) decreases via unknown mechanisms to conserve energy. In small mammals, non-shivering thermogenesis in brown adipose tissue (BAT) is critical to T b regulation; therefore, we hypothesize that hypoxia decreases naked mole-rat BAT thermogenesis. To test this, we measure changes in T b during normoxia and hypoxia (7% O 2 ; 1–3 h). We report that interscapular thermogenesis is high in normoxia but ceases during hypoxia, and T b decreases. Furthermore, in BAT from animals treated in hypoxia, UCP1 and mitochondrial complexes I-V protein expression rapidly decrease, while mitochondria undergo fission, and apoptosis and mitophagy are inhibited. Finally, UCP1 expression decreases in hypoxia in three other social African mole-rat species, but not a solitary species. These findings suggest that the ability to rapidly down-regulate thermogenesis to conserve oxygen in hypoxia may have evolved preferentially in social species.