Potentially Important Role for Sarcolipin in Skeletal Muscle Thermogenesis

摘要

Numerous studies have shown that brown fat plays a major role in non-shivering thermogenesis (NST) and that increased brown fat thermogenesis protects against diet-induced obesity and insulin resistance. However, unlike rodents, most humans have relatively low levels of brown fat, suggesting that obesity- and diabetes-related interventions directed at NST may not necessarily be effective. Recent data from Bal et al. demonstrate that skeletal muscle also plays a key role in NST and that sarcolipin, a regulator of sarcoplasmic reticulum calcium cycling, is required for NST in this tissue. In an initial set of experiments in which intrascapular BAT (representing 60% of all BAT) was removed from both sarcolipin knockout and wild-type mice that were housed at 22 ± 1.5℃, no differences in core temperature were observed between the two groups. However, subsequent experiments in which the temperature was reduced to 4℃ showed that sarcolipin~(-/) mice with ablated BAT could not maintain core temperature and died of hypothermia. In contrast, sarcolipin~(-/-) mice with intact BAT survived, but with a somewhat lower core temperature.