scholarly journals Naked mole-rat brown fat thermogenesis is diminished during hypoxia through a rapid decrease in UCP1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hang Cheng ◽  
Rajaa Sebaa ◽  
Nikita Malholtra ◽  
Baptiste Lacoste ◽  
Ziyad El Hankouri ◽  
...  

AbstractNaked mole-rats are among the most hypoxia-tolerant mammals. During hypoxia, their body temperature (Tb) decreases via unknown mechanisms to conserve energy. In small mammals, non-shivering thermogenesis in brown adipose tissue (BAT) is critical to Tb regulation; therefore, we hypothesize that hypoxia decreases naked mole-rat BAT thermogenesis. To test this, we measure changes in Tb during normoxia and hypoxia (7% O2; 1–3 h). We report that interscapular thermogenesis is high in normoxia but ceases during hypoxia, and Tb 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.

2020 ◽  
Author(s):  
Yuki Oiwa ◽  
Kaori Oka ◽  
Hironobu Yasui ◽  
Kei Higashikawa ◽  
Hidemasa Bono ◽  
...  

AbstractThe naked mole-rat (NMR) is a poikilothermic mammal that forms eusocial colonies consisting of one breeding queen, several breeding kings, and subordinates. Despite their poikilothermic feature, NMRs possess brown adipose tissue (BAT), which in homeothermic mammals induces thermogenesis in cold environments. However, NMR-BAT thermogenic potential is controversial, and its physiological roles are unknown. Here, we show that NMR-BAT has beta-3 adrenergic receptor (ADRB3)-dependent thermogenic potential, which contributes to thermogenesis in the isolated queen in non-cold environments. NMR-BAT expressed several brown adipocyte marker genes and showed noradrenaline-dependent thermogenic activity in vitro and in vivo. Although our ADRB3 inhibition experiments revealed that NMR-BAT thermogenesis slightly delays the decrease in body temperature in a cold environment, it was insufficient to maintain the body temperatures of the NMRs. In a non-cold environment, NMRs are known to increase their body temperature by a heat-sharing behavior. Interestingly, we found that the body temperatures of NMRs isolated from the colony were also significantly higher than the ambient temperature. We also show that queens, but not subordinates, induce BAT thermogenesis in isolated, non-cold conditions. Our research provides novel insights into the role and mechanism of thermoregulation in this unique poikilothermic mammal.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuki Oiwa ◽  
Kaori Oka ◽  
Hironobu Yasui ◽  
Kei Higashikawa ◽  
Hidemasa Bono ◽  
...  

Abstract The naked mole-rat (NMR) is a heterothermic mammal that forms eusocial colonies consisting of one reproductive female (queen), several reproductive males, and subordinates. Despite their heterothermy, NMRs possess brown adipose tissue (BAT), which generally induces thermogenesis in cold and some non-cold environments. Previous studies suggest that NMR-BAT induces thermogenesis by cold exposure. However, detailed NMR-BAT characteristics and whether NMR-BAT thermogenesis occurs in non-cold environments are unknown. Here, we show beta-3 adrenergic receptor (ADRB3)-dependent thermogenic potential of NMR-BAT, which contributes to thermogenesis in the isolated queen in non-cold environments (30 °C). NMR-BAT expressed several brown adipocyte marker genes and showed noradrenaline-dependent thermogenic activity in vitro and in vivo. Although our ADRB3 inhibition experiments revealed that NMR-BAT thermogenesis slightly delays the decrease in body temperature in a cold environment (20 °C), it was insufficient to prevent the decrease in the body temperatures. Even at 30 °C, NMRs are known to prevent the decrease of and maintain their body temperature by heat-sharing behaviors within the colony. However, isolated NMRs maintained their body temperature at the same level as when they are in the colony. Interestingly, we found that queens, but not subordinates, induce BAT thermogenesis in this condition. Our research provides novel insights into NMR thermoregulation.


Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 111
Author(s):  
Eunhee Cho ◽  
Da Yeon Jeong ◽  
Jae Geun Kim ◽  
Sewon Lee

Irisin is a myokine primarily secreted by skeletal muscles and is known as an exercise-induced hormone. The purpose of this study was to determine whether the PGC-1α -FNDC5 /Irisin-UCP1 expression which is an irisin-related signaling pathway, is activated by an acute swimming exercise. Fourteen to sixteen weeks old male C57BL/6J mice (n = 20) were divided into control (CON, n = 10) and swimming exercise groups (SEG, n = 10). The SEG mice performed 90 min of acute swimming exercise, while control (non-exercised) mice were exposed to shallow water (2 cm of depth) for 90 min. The mRNA and protein expression of PGC-1α, FNDC5 and browning markers including UCP1 were evaluated by quantitative real-time PCR and western blotting. Serum irisin concentration was measured by enzyme-linked immunosorbent assay. An acute swimming exercise did not lead to alterations in the mRNA and protein expression of PGC-1α in both soleus and gastrocnemius muscles, the mRNA and protein expression of UCP1 in brown adipose tissue, mRNA browning markers in visceral adipose tissue and circulating irisin when compared with the control group. On the other hand, an acute swimming exercise led to increases in the mRNA and protein expressions of FNDC5 in the soleus muscle, the protein expression of FNDC5 in the gastrocnemius muscles and the protein expression of UCP1 in subcutaneous adipose tissue.


Nature ◽  
1965 ◽  
Vol 206 (4980) ◽  
pp. 201-202 ◽  
Author(s):  
M. J. R. DAWKINS ◽  
J. W. SCOPES

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Carmen P. Wong ◽  
Urszula T. Iwaniec ◽  
Russell T. Turner

AbstractSixteen-week-old female C57BL/6J mice were sacrificed aboard the International Space Station after 37 days of flight (RR-1 mission) and frozen carcasses returned to Earth. RNA was isolated from interscapular brown adipose tissue (BAT) and gonadal white adipose tissue (WAT). Spaceflight resulted in differential expression of genes in BAT consistent with increased non-shivering thermogenesis and differential expression of genes in WAT consistent with increased glucose uptake and metabolism, adipogenesis, and β-oxidation.


2014 ◽  
Vol 1837 ◽  
pp. e26-e27
Author(s):  
Igor Golic ◽  
Milica Markelic ◽  
Ksenija Velickovic ◽  
Aleksandra Jankovic ◽  
Ana Stancic ◽  
...  

PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0209225
Author(s):  
Evie P. M. Broeders ◽  
Guy H. E. J. Vijgen ◽  
Bas Havekes ◽  
Nicole D. Bouvy ◽  
Felix M. Mottaghy ◽  
...  

Author(s):  
Soren Z. Coulson ◽  
Cayleih E. Robertson ◽  
Sajeni Mahalingam ◽  
Grant B. McClelland

High altitude environments challenge small mammals with persistent low ambient temperatures that require high rates of aerobic heat production in face of low O2 availability. An important component of thermogenic capacity in rodents is non-shivering thermogenesis (NST) mediated by uncoupled mitochondrial respiration in brown adipose tissue (BAT). NST is plastic, and capacity for heat production increases with cold acclimation. However, in lowland native rodents, hypoxia inhibits NST in BAT. We hypothesize that highland deer mice (Peromyscus maniculatus) overcome the hypoxic inhibition of NST through changes in BAT mitochondrial function. We tested this hypothesis using lab born and raised highland and lowland deer mice, and a lowland congeneric (P. leucopus), acclimated to either warm normoxia (25°C, 760 mmHg) or cold hypoxia (5°C, 430 mmHg). We determined the effects of acclimation and ancestry on whole-animal rates of NST, the mass of interscapular BAT (iBAT), and uncoupling protein (UCP)-1 protein expression. To identify changes in mitochondrial function, we conducted high-resolution respirometry on isolated iBAT mitochondria using substrates and inhibitors targeted to UCP-1. We found that rates of NST increased with cold hypoxia acclimation but only in highland deer mice. There was no effect of cold hypoxia acclimation on iBAT mass in any group, but highland deer mice showed increases in UCP-1 expression and UCP-1 stimulated mitochondrial respiration in response to these stressors. Our results suggest that highland deer mice have evolved to increase the capacity for NST in response to chronic cold hypoxia, driven in part by changes in iBAT mitochondrial function.


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