Brown adipose tissue (BAT) plays an important role on no shivering thermogenesis during cold exposure to maintain animal body temperature and energy homeostasis. However, knowledge of the cellular transition from white adipose tissue (WAT) to BAT is still limited. In this study, we provided a comprehensive metabolomics and transcriptional signatures of goat BAT and WAT. A total of 157 metabolites were significantly changed, including 81 upregulated and 76 downregulated metabolites. In addition, we identified the citric acid cycle, fatty acid elongation, and degradation pathways as coordinately activated in BAT. Interestingly, five unsaturated fatty acids (Eicosadienoic Acid, C20:2; γ-Linolenic acid, C20:3; Arachidonic Acid, C20:4; Adrenic acid, C22:4; Docosahexaenoic acid, C22:6), Succinate, L-carnitine, and L-palmitoyl-carnitine were found to be abundant in BAT. Furthermore, L-carnitine, an intermediate of fatty acid degradation, is required for goat brown adipocyte differentiation and thermogenesis through activating AMPK pathway. However, L-carnitine decreased lipid accumulation through inducing lipolysis and thermogenesis in white adipocytes. These results revealed that there are the significant alterations in transcriptomic and metabolomic profiles between goat WAT and BAT, which may contribute to better understanding the roles of metabolites in BAT thermogenesis process.

中文翻译：

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代谢组学和RNA-seq的综合应用揭示山羊棕色脂肪组织的产热调节

棕色脂肪组织 (BAT) 在冷暴露期间不发抖的产热中起着重要作用，以维持动物体温和能量稳态。然而，关于从白色脂肪组织 (WAT) 到 BAT 的细胞转变的知识仍然有限。在这项研究中，我们提供了山羊 BAT 和 WAT 的综合代谢组学和转录特征。共有 157 种代谢物发生了显着变化，包括 81 种上调和 76 种下调的代谢物。此外，我们确定了在 BAT 中协同激活的柠檬酸循环、脂肪酸延伸和降解途径。有趣的是，五种不饱和脂肪酸（二十碳二烯酸，C20:2；γ-亚麻酸，C20:3；花生四烯酸，C20:4；肾上腺素酸，C22:4；二十二碳六烯酸，C22:6）、琥珀酸、L-肉碱, 和 L-棕榈酰肉碱被发现在 BAT 中含量丰富。此外，L-肉碱是脂肪酸降解的中间体，通过激活 AMPK 途径，是山羊棕色脂肪细胞分化和产热所必需的。然而，左旋肉碱通过诱导白色脂肪细胞中的脂肪分解和产热来减少脂质积累。这些结果表明，山羊 WAT 和 BAT 之间的转录组学和代谢组学特征存在显着变化，这可能有助于更好地了解代谢物在 BAT 产热过程中的作用。L-肉碱通过诱导白色脂肪细胞中的脂肪分解和产热来减少脂质积累。这些结果表明，山羊 WAT 和 BAT 之间的转录组学和代谢组学特征存在显着变化，这可能有助于更好地了解代谢物在 BAT 产热过程中的作用。L-肉碱通过诱导白色脂肪细胞中的脂肪分解和产热来减少脂质积累。这些结果表明，山羊 WAT 和 BAT 之间的转录组学和代谢组学特征存在显着变化，这可能有助于更好地了解代谢物在 BAT 产热过程中的作用。