This study analysed the effects of 24 hours of cold stress (22°C or 5°C vs. mice maintained at 30°C) on the plasma, brown adipose tissue (BAT), subcutaneous (SubQ) and epididymal (Epi) white adipose tissue (WAT), liver, and skeletal muscle lipidome of mice. Using mass spectrometry-lipidomics 624 lipid species were detected, of which 239 were significantly altered in plasma, 134 in BAT, and 51 in the liver. In plasma, acylcarnitines and free fatty acids were markedly increased at 5°C. Plasma triacylglycerols (TGs) were reduced at 22°C and 5°C. We also identified ether lipids as a novel, cold-induced lipid class. In BAT, TGs were the principal lipid class affected by cold stress, being significantly reduced at both 22°C and 5°C. Interestingly, while BAT TG species were uniformly affected at 5°C, at 22°C we observed species-dependent effects, with TGs containing longer and more unsaturated fatty acids particularly sensitive to the effects of cold. In the liver, TGs were the most markedly affected lipid class, increasing in abundance at 5°C. TGs containing longer and more unsaturated fatty acids accumulated to a greater degree. Our work demonstrates: (1) Acute exposure to moderate (22°C) cold stress alters the plasma and BAT lipidome; although this effect is markedly less pronounced than at 5°C. (2) Cold stress at 5°C dramatically alters the plasma lipidome, with ether lipids identified as a novel lipid class altered by cold exposure. (3) That cold-induced alterations in liver and BAT TG levels are not uniform, with changes being influenced by acyl chain composition.

中文翻译：

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响应中度和重度冷应激小鼠脂质组循环和组织特异性改变的特征

这项研究分析了24小时冷应激（22°C或5°C，相对于维持在30°C的小鼠）对血浆，棕色脂肪组织（BAT），皮下（SubQ）和附睾（Epi）白色脂肪的影响小鼠的组织（WAT），肝脏和骨骼肌脂质组。使用质谱-脂质组学检测到624种脂质种类，其中239种在血浆中发生了显着变化，BAT发生了134种变化，肝脏发生了51种变化。在血浆中，酰基肉碱和游离脂肪酸在5°C时显着增加。血浆三酰基甘油（TGs）在22°C和5°C时降低。我们还确定了醚类脂是一种新型的冷诱导类脂。在BAT中，TGs是受冷胁迫影响的主要脂质类别，在22℃和5℃下均显着降低。有趣的是，虽然BAT TG物种在5°C下受到均匀影响，但在22°C下，我们观察到了物种依赖性效应，含有更长和更多不饱和脂肪酸的甘油三酯，对寒冷的影响特别敏感。在肝脏中，TGs是受影响最明显的脂质类别，在5°C时丰度增加。含有更长和更多不饱和脂肪酸的TG积累程度更高。我们的工作表明：（1）急性暴露于中等温度（22°C）的冷胁迫会改变血浆和BAT脂质组。尽管这种作用明显不如5℃明显。（2）5°C下的冷胁迫会极大地改变血浆脂质组，而被识别为新型脂质类别的醚脂质会因冷暴露而改变。（3）寒冷引起的肝脏和BAT TG水平变化并不均匀，变化受酰基链组成的影响。TG是受影响最明显的脂质类别，在5°C时丰度增加。含有更长和更多不饱和脂肪酸的TG积累程度更高。我们的工作表明：（1）急性暴露于中等温度（22°C）的冷胁迫会改变血浆和BAT脂质组。尽管这种作用明显不如5℃明显。（2）5°C下的冷胁迫会极大地改变血浆脂质组，而被识别为新型脂质类别的醚脂质会因冷暴露而改变。（3）寒冷引起的肝脏和BAT TG水平变化并不均匀，变化受酰基链组成的影响。TG是受影响最明显的脂质类别，在5°C时丰度增加。含有更长和更多不饱和脂肪酸的TG积累程度更高。我们的工作表明：（1）急性暴露于中等温度（22°C）的冷胁迫会改变血浆和BAT脂质组。尽管这种作用明显不如5℃明显。（2）5°C下的冷胁迫会极大地改变血浆脂质组，而被识别为新型脂质类别的醚脂质会因冷暴露而改变。（3）寒冷引起的肝脏和BAT TG水平变化并不均匀，变化受酰基链组成的影响。（1）急性暴露于中度（22°C）冷应激会改变血浆和BAT脂质组; 尽管这种作用明显不如5℃明显。（2）5°C下的冷胁迫会极大地改变血浆脂质组，而被识别为新型脂质类别的醚脂质会因冷暴露而改变。（3）寒冷引起的肝脏和BAT TG水平变化并不均匀，变化受酰基链组成的影响。（1）急性暴露于中度（22°C）冷应激会改变血浆和BAT脂质组; 尽管这种作用明显不如5℃明显。（2）5°C下的冷胁迫会极大地改变血浆脂质组，而被识别为新型脂质类别的醚脂质会因冷暴露而改变。（3）寒冷引起的肝脏和BAT TG水平变化并不均匀，变化受酰基链组成的影响。