Department of General Pediatrics, Center for Pediatrics and Adolescent Medicine, Faculty of Medicine and Medical Centre, University of Freiburg, 79106 Freiburg, Germany; University of Freiburg, Faculty of Biology, Schaenzlestrasse 1, D-79104 Freiburg, Germany.
Department of General Pediatrics, Center for Pediatrics and Adolescent Medicine, Faculty of Medicine and Medical Centre, University of Freiburg, 79106 Freiburg, Germany.
Biochim Biophys Acta Mol Cell Biol Lipids. 2019 Nov;1864(11):1629-1643. doi: 10.1016/j.bbalip.2019.07.012. Epub 2019 Jul 31.
Malonyl-CoA synthetase (ACSF3) catalyzes the first step of the mitochondrial fatty acid biosynthesis (mtFASII). Mutations in ACSF3 cause CMAMMA a rare inborn error of metabolism. The clinical phenotype is very heterogeneous, with some patients presenting with neurologic manifestations. In some children, presenting symptoms such as coma, ketoacidosis and hypoglycemia are suggestive of an intermediary metabolic disorder. The overall pathophysiological mechanisms are not understood. In order to study the role of mtFASII in the regulation of energy metabolism we performed a comprehensive metabolic phenotyping with Seahorse technology proteomics in fibroblasts from healthy controls and ACSF3 patients. SILAC-based proteomics and lipidomic analysis were performed to investigate the effects of hypofunctional mtFASII on proteome and lipid homeostasis of complex lipids. Our data clearly confirmed an impaired mitochondrial flexibility characterized by reduced mitochondrial respiration and glycolytic flux due to a lower lipoylation degree. These findings were accompanied by the adaptational upregulation of β-oxidation and by the reduction of anaplerotic amino acids as compensatory mechanism to address the required energy need. Finally, lipidomic analysis demonstrated that the content of the bioactive lipids sphingomyelins and cardiolipins was strongly increased. Our data clearly demonstrate the role of mtFASII in metabolic regulation. Moreover, we show that mtFASII acts as mediator in the lipid-mediated signaling processes in the regulation of energy homeostasis and metabolic flexibility.
丙二酰辅酶 A 合成酶 (ACSF3) 催化线粒体脂肪酸生物合成 (mtFASII) 的第一步。ACSF3 基因突变导致 CMAMMA 这是一种罕见的先天性代谢错误。临床表现非常异质，一些患者表现出神经表现。在一些儿童中，昏迷、酮症酸中毒和低血糖等首发症状提示存在中间代谢障碍。整体病理生理机制尚不清楚。为了研究 mtFASII 在能量代谢调节中的作用，我们使用 Seahorse 技术对来自健康对照和 ACSF3 患者的成纤维细胞进行了全面代谢表型分析。使用 SILAC 基于的蛋白质组学和脂质组学分析来研究低功能 mtFASII 对复杂脂质的蛋白质组和脂质稳态的影响。我们的数据清楚地证实了线粒体灵活性受损，其特征是由于较低的脂酰化程度导致线粒体呼吸和糖酵解通量降低。这些发现伴随着β氧化的适应性上调，以及氨酰基供体氨基酸的减少作为补偿机制来满足所需的能量需求。最后，脂质组学分析表明生物活性脂质鞘磷脂和心磷脂的含量大大增加。我们的数据清楚地表明 mtFASII 在代谢调节中的作用。此外，我们表明 mtFASII 作为脂质介导的信号通路在调节能量平衡和代谢灵活性中的介质。
