Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.
Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, the Netherlands.
FASEB J. 2024 Feb 29;38(4):e23478. doi: 10.1096/fj.202302163R.
Carnitine derivatives of disease-specific acyl-CoAs are the diagnostic hallmark for long-chain fatty acid β-oxidation disorders (lcFAOD), including carnitine shuttle deficiencies, very-long-chain acyl-CoA dehydrogenase deficiency (VLCADD), long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) and mitochondrial trifunctional protein deficiency (MPTD). The exact consequence of accumulating lcFAO-intermediates and their influence on cellular lipid homeostasis is, however, still unknown. To investigate the fate and cellular effects of the accumulating lcFAO-intermediates and to explore the presence of disease-specific markers, we used tracer-based lipidomics with deuterium-labeled oleic acid (D9-C18:1) in lcFAOD patient-derived fibroblasts. In line with previous studies, we observed a trend towards neutral lipid accumulation in lcFAOD. In addition, we detected a direct connection between the chain length and patterns of (un)saturation of accumulating acylcarnitines and the various enzyme deficiencies. Our results also identified two disease-specific candidate biomarkers. Lysophosphatidylcholine(14:1) (LPC(14:1)) was specifically increased in severe VLCADD compared to mild VLCADD and control samples. This was confirmed in plasma samples showing an inverse correlation with enzyme activity, which was better than the classic diagnostic marker C14:1-carnitine. The second candidate biomarker was an unknown lipid class, which we identified as S-(3-hydroxyacyl)cysteamines. We hypothesized that these were degradation products of the CoA moiety of accumulating 3-hydroxyacyl-CoAs. S-(3-hydroxyacyl)cysteamines were significantly increased in LCHADD compared to controls and other lcFAOD, including MTPD. Our findings suggest extensive alternative lipid metabolism in lcFAOD and confirm that lcFAOD accumulate neutral lipid species. In addition, we present two disease-specific candidate biomarkers for VLCADD and LCHADD, that may have significant relevance for disease diagnosis, prognosis, and monitoring.
酰基辅酶 A 衍生物是长链脂肪酸β氧化障碍（lcFAOD）的诊断标志，包括肉碱穿梭缺陷、极长链酰基辅酶 A 脱氢酶缺乏症（VLCADD）、长链 3-羟基酰基辅酶 A 脱氢酶缺乏症（LCHADD）和线粒体三功能蛋白缺乏症（MPTD）。然而，lcFAO 中间体的积累的确切后果及其对细胞脂质稳态的影响仍不清楚。为了研究积累的 lcFAO 中间体的命运和细胞效应，并探索是否存在疾病特异性标志物，我们使用氘标记油酸（D9-C18:1）的示踪脂质组学方法，在 lcFAOD 患者来源的成纤维细胞中进行研究。与先前的研究一致，我们观察到 lcFAOD 中中性脂质积累的趋势。此外，我们还发现积累的酰基辅酶 A 的链长和（不）饱和度模式与各种酶缺乏之间存在直接联系。我们的研究结果还确定了两种疾病特异性候选生物标志物。与轻度 VLCADD 和对照样本相比，严重 VLCADD 中溶血磷脂酰胆碱（14:1）（LPC（14:1））明显增加。在血浆样本中得到了证实，其与酶活性呈负相关，优于经典诊断标志物 C14:1-肉碱。第二个候选生物标志物是一种未知的脂质类，我们将其鉴定为 S-（3-羟基酰基）半胱胺。我们假设这些是积累的 3-羟基酰基辅酶 A 的 CoA 部分的降解产物。与对照组和其他 lcFAOD（包括 MTPD）相比，LCHADD 中 S-（3-羟基酰基）半胱胺明显增加。我们的研究结果表明 lcFAOD 中存在广泛的替代脂质代谢，并证实 lcFAOD 会积累中性脂质。此外，我们还提出了 VLCADD 和 LCHADD 的两种疾病特异性候选生物标志物，它们可能对疾病诊断、预后和监测具有重要意义。
