Bal 2017 J Biol Chem
|Bal NC, Singh S, Reis FCG, Maurya SK, Pani S, Rowland LA, Periasamy M (2017) Both brown adipose tissue and skeletal muscle thermogenesis processes are activated during mild to severe cold adaptation in mice. J Biol Chem 292:16616-25.|
Abstract: Thermogenesis is an important homeostatic mechanism essential for survival and normal physiological functions in mammals. Both brown adipose tissue (BAT) (i.e. uncoupling protein 1 (UCP1)-based) and skeletal muscle (i.e. sarcolipin (SLN)-based) thermogenesis processes play important roles in temperature homeostasis, but their relative contributions differ from small to large mammals. In this study, we investigated the functional interplay between skeletal muscle- and BAT-based thermogenesis under mild versus severe cold adaptation by employing UCP1-/- and SLN-/- mice. Interestingly, adaptation of SLN-/- mice to mild cold conditions (16 °C) significantly increased UCP1 expression, suggesting increased reliance on BAT-based thermogenesis. This was also evident from structural alterations in BAT morphology, including mitochondrial architecture, increased expression of electron transport chain proteins, and depletion of fat droplets. Similarly, UCP1-/- mice adapted to mild cold up-regulated muscle-based thermogenesis, indicated by increases in muscle succinate dehydrogenase activity, SLN expression, mitochondrial content, and neovascularization, compared with WT mice. These results further confirm that SLN-based thermogenesis is a key player in muscle non-shivering thermogenesis (NST) and can compensate for loss of BAT activity. We also present evidence that the increased reliance on BAT-based NST depends on increased autonomic input, as indicated by abundant levels of tyrosine hydroxylase and neuropeptide Y. Our findings demonstrate that both BAT and muscle-based NST are equally recruited during mild and severe cold adaptation and that loss of heat production from one thermogenic pathway leads to increased recruitment of the other, indicating a functional interplay between these two thermogenic processes.
• Keywords: Adipose tissue, Calcium ATPase, Calcium-binding protein, Skeletal muscle, Uncoupling protein • Bioblast editor: Kandolf G
Labels: MiParea: Respiration
Stress:Temperature Organism: Mouse Tissue;cell: Skeletal muscle, Fat Preparation: Permeabilized tissue
Coupling state: LEAK, OXPHOS Pathway: N, NS HRR: Oxygraph-2k