ABSTRACT
Medium-chain fatty acids (mc-FAs) are currently applied in the treatment of long-chain fatty acid oxidation disorders (lc-FAOD) characterized by impaired ß-oxidation. Here, we performed lipidomic and proteomic analysis in fibroblasts from patients with very long-chain acyl-CoA dehydrogenase (VLCADD) and long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHADD) deficiencies after incubation with heptanoate (C7) and octanoate (C8). Defects of ß-oxidation induced striking proteomic alterations, whereas the effect of treatment with mc-FAs was minor. However, mc-FAs induced a remodeling of complex lipids. Especially C7 appeared to act protectively by restoring sphingolipid biosynthesis flux and improving the observed dysregulation of protein homeostasis in LCHADD under control conditions.
Subject(s)
Caprylates/pharmacology , Fibroblasts/drug effects , Heptanoates/pharmacology , Lipid Metabolism, Inborn Errors/metabolism , Lipidomics/methods , Proteomics/methods , Acyl-CoA Dehydrogenase, Long-Chain/deficiency , Acyl-CoA Dehydrogenase, Long-Chain/metabolism , Cardiolipins/metabolism , Cell Line , Female , Fibroblasts/metabolism , Genotype , Humans , Lipid Metabolism, Inborn Errors/genetics , Lipid Metabolism, Inborn Errors/pathology , Male , Mitochondria/drug effects , Mitochondria/metabolism , Phosphatidylcholines/metabolism , Phosphatidylethanolamines/metabolism , Proteome/metabolism , Sphingolipids/metabolismABSTRACT
Long-chain fatty acid oxidation disorders (lc-FAOD) are a group of diseases affecting the degradation of long-chain fatty acids. In order to investigate the disease specific alterations of the cellular lipidome, we performed undirected lipidomics in fibroblasts from patients with carnitine palmitoyltransferase II, very long-chain acyl-CoA dehydrogenase, and long-chain 3-hydroxyacyl-CoA dehydrogenase. We demonstrate a deep remodeling of mitochondrial cardiolipins. The aberrant phosphatidylcholine/phosphatidylethanolamine ratio and the increased content of plasmalogens and of lysophospholipids support the theory of an inflammatory phenotype in lc-FAOD. Moreover, we describe increased ratios of sphingomyelin/ceramide and sphingomyelin/hexosylceramide in LCHAD deficiency which may contribute to the neuropathic phenotype of LCHADD/mitochondrial trifunctional protein deficiency.
Subject(s)
Fatty Acids/metabolism , Fibroblasts/enzymology , Lipid Metabolism, Inborn Errors/enzymology , Lipidomics , Metabolome , Skin/enzymology , Acyl-CoA Dehydrogenase, Long-Chain/deficiency , Acyl-CoA Dehydrogenase, Long-Chain/genetics , Cardiolipins/metabolism , Carnitine O-Palmitoyltransferase/deficiency , Carnitine O-Palmitoyltransferase/genetics , Case-Control Studies , Cells, Cultured , Ceramides/metabolism , Female , Humans , Lipid Metabolism, Inborn Errors/genetics , Long-Chain-3-Hydroxyacyl-CoA Dehydrogenase/deficiency , Long-Chain-3-Hydroxyacyl-CoA Dehydrogenase/genetics , Male , Metabolism, Inborn Errors/enzymology , Metabolism, Inborn Errors/genetics , Oxidation-Reduction , Sphingolipids/metabolism , Tandem Mass SpectrometryABSTRACT
Very-long-chain acyl-CoA dehydrogenase deficiency (VLCAD) is the most common defect of long-chain fatty acid ß-oxidation. The recommended treatment includes the application of medium-chain triacylglycerols (MCTs). However, long-term treatment of VLCAD-/- mice resulted in the development of a sex-specific metabolic syndrome due to the selective activation of the ERK/mTORc1 signalling in females and ERK/peroxisome proliferator-activated receptor gamma pathway in males. In order to investigate a subsequent sex-specific effect of MCT on the lipid composition of the cellular membranes, we performed lipidomic analysis, SILAC-based quantitative proteomics and gene expression in fibroblasts from WT and VLCAD-/- mice of both sexes. Treatment with octanoate (C8) affected the composition of complex lipids resulting in a sex-specific signature of the molecular profile. The content of ceramides and sphingomyelins in particular differed significantly under control conditions and increased markedly in cells from mutant female mice but remained unchanged in cells from mutant males. Moreover, we observed a specific upregulation of biosynthesis of plasmalogens only in male mice, whereas in females C8 led to the accumulation of higher concentration of phosphatidylcholines and lysophosphatidylcholines. Our data on membrane lipids in VLCAD after supplementation with C8 provide evidence of a sex-specific lipid perturbation. We hypothesize a likely C8-induced pro-inflammatory response contributing to the development of a severe metabolic syndrome in female VLCAD-/- mice on long-term MCT supplementation.