Faculty of Health Sciences, University of Macau, Macau SAR, China.
Faculty of Health Sciences, University of Macau, Macau SAR, China; Division of Radiation Oncology, National Cancer Centre Singapore, Singapore; Division of Medical Sciences, National Cancer Centre Singapore, Singapore; Oncology Academic Programme, Duke-NUS Medical School, Singapore.
EBioMedicine. 2020 Jan;51:102605. doi: 10.1016/j.ebiom.2019.102605. Epub 2020 Jan 2.
Metabolic modulation is capable of maintaining cell potency, regulating niche homeostasis, or determining cell fate. However, little is known regarding the metabolic landscape during early adipogenesis or whether metabolic modulation could be a potential approach for obesity treatment.
The metabolic footprint during adipocyte commitment was evaluated by metabolomics analysis in mouse embryonic fibroblasts (MEFs). The role of apoptosis induced by ceramide and how ceramide is regulated were evaluated by omics analysis in vitro, human database and the adipocyte-specific Sirt1 knockout mouse.
The metabolic footprint showed that a complicated diversity of metabolism was enriched as early as 3 h and tended to fluctuate throughout differentiation. Subsequently, the scale of these perturbed metabolic patterns was reduced to reach a balanced state. Of high relevance is the presence of apoptosis induced by ceramide accumulation, which is associated with metabolic dynamics. Interestingly, apoptotic cells were not merely a byproduct of adipogenesis but rather promoted the release of lipid components to facilitate adipogenesis. Mechanistically, ceramide accumulation stemming from hydrolysis and the de novo pathway during early adipogenesis is regulated by Sirt1 upon epigenetic alterations of constitutive Histone H3K4 methylation and H3K9 acetylation.
The metabolic footprint during adipocyte commitment highlights that apoptosis induced by ceramide is essential for adipogenesis, which is reversed by suppression of Sirt1. Therefore, Sirt1 may constitute a target to treat obesity or other ceramide-associated metabolic syndromes.
This project was supported by grants from the University of Macau (SRG2015-00008-FHS, MYRG2016-00054-FHS and MYRG2017-00096-FHS to RHW; CPG2019-00019-FHS to CXD) and from the National Natural Science Foundation of China (81672603 and 81401978) to QC.
代谢调节能够维持细胞潜能、调节龛位内稳态或决定细胞命运。然而,人们对于早期脂肪生成过程中的代谢特征知之甚少,也不知道代谢调节是否可以作为肥胖治疗的一种潜在方法。
通过代谢组学分析,在小鼠胚胎成纤维细胞(MEFs)中评估脂肪细胞分化过程中的代谢特征。通过体外、人类数据库和脂肪细胞特异性 Sirt1 敲除小鼠中的组学分析,评估神经酰胺诱导的细胞凋亡的作用及其调控机制。
代谢特征表明,复杂多样的代谢在 3 小时内就被富集,并在分化过程中趋于波动。随后,这些紊乱的代谢模式的规模减小,达到平衡状态。值得注意的是,神经酰胺积累诱导的细胞凋亡与代谢动力学有关。有趣的是,凋亡细胞不仅仅是脂肪生成的副产物,而且促进了脂质成分的释放,从而促进了脂肪生成。从机制上讲,早期脂肪生成过程中神经酰胺积累源自水解和从头合成途径,受组蛋白 H3K4 甲基化和 H3K9 乙酰化的表观遗传改变调控,Sirt1 会调节该途径。
脂肪细胞分化过程中的代谢特征表明,神经酰胺诱导的细胞凋亡对于脂肪生成至关重要,而 Sirt1 的抑制可以逆转这种作用。因此,Sirt1 可能成为治疗肥胖症或其他与神经酰胺相关的代谢综合征的靶点。
本项目得到了澳门大学(SRG2015-00008-FHS、MYRG2016-00054-FHS 和 MYRG2017-00096-FHS 项目资助,RHW;CPG2019-00019-FHS 项目资助,CXD)和国家自然科学基金(81672603 和 81401978 项目资助,QC)的支持。