Dataset Information

Functional analysis of molecular and pharmacological modulators of mitochondrial fatty acid oxidation.

ABSTRACT: Fatty acid oxidation (FAO) is a key bioenergetic pathway often dysregulated in diseases. The current knowledge on FAO regulators in mammalian cells is limited and sometimes controversial. Previous FAO analyses involve nonphysiological culture conditions or lack adequate quantification. We herein described a convenient and quantitative assay to monitor dynamic FAO activities of mammalian cells in physiologically relevant settings. The method enabled us to assess various molecular and pharmacological modulators of the FAO pathway in established cell lines, primary cells and mice. Surprisingly, many previously proposed FAO inhibitors such as ranolazine and trimetazidine lacked FAO-interfering activity. In comparison, etomoxir at low micromolar concentrations was sufficient to saturate its target proteins and to block cellular FAO function. Oxfenicine, on the other hand, acted as a partial inhibitor of FAO. As another class of FAO inhibitors that transcriptionally repress FAO genes, antagonists of peroxisome proliferator-activated receptors (PPARs), particularly that of PPAR?, significantly decreased cellular FAO activity. Our assay also had sufficient sensitivity to monitor upregulation of FAO in response to environmental glucose depletion and other energy-demanding cues. Altogether this study provided a reliable FAO assay and a clear picture of biological properties of potential FAO modulators in the mammalian system.

SUBMITTER: Ma Y

PROVIDER: S-EPMC6989517 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Functional analysis of molecular and pharmacological modulators of mitochondrial fatty acid oxidation.

Ma Yibao Y Wang Wei W Devarakonda Teja T Zhou Huiping H Wang Xiang-Yang XY Salloum Fadi N FN Spiegel Sarah S Fang Xianjun X

Scientific reports 20200129 1

Fatty acid oxidation (FAO) is a key bioenergetic pathway often dysregulated in diseases. The current knowledge on FAO regulators in mammalian cells is limited and sometimes controversial. Previous FAO analyses involve nonphysiological culture conditions or lack adequate quantification. We herein described a convenient and quantitative assay to monitor dynamic FAO activities of mammalian cells in physiologically relevant settings. The method enabled us to assess various molecular and pharmacologi ...[more]

PMID: 31996743

Similar Datasets

Project description:BackgroundThe oxidation of fatty acids in mitochondria plays an important role in energy metabolism and genetic disorders of this pathway may cause metabolic diseases. Enzyme deficiencies can block the metabolism at defined reactions in the mitochondrion and lead to accumulation of specific substrates causing severe clinical manifestations. Ten of the disorders directly affecting mitochondrial fatty acid oxidation have been well-defined, implicating episodic hypoketotic hypoglycemia provoked by catabolic stress, multiple organ failure, muscle weakness, or hypertrophic cardiomyopathy. Additionally, syndromes of severe maternal illness (HELLP syndrome and AFLP) have been associated with pregnancies carrying a fetus affected by fatty acid oxidation deficiencies. However, little is known about fatty acids kinetics, especially during fasting or exercise when the demand for fatty acid oxidation is increased (catabolic stress).ResultsA computational kinetic network of 64 reactions with 91 compounds and 301 parameters was constructed to study dynamic properties of mitochondrial fatty acid beta-oxidation. Various deficiencies of acyl-CoA dehydrogenase were simulated and verified with measured concentrations of indicative metabolites of screened newborns in Middle Europe and South Australia. The simulated accumulation of specific acyl-CoAs according to the investigated enzyme deficiencies are in agreement with experimental data and findings in literature. Investigation of the dynamic properties of the fatty acid beta-oxidation reveals that the formation of acetyl-CoA - substrate for energy production - is highly impaired within the first hours of fasting corresponding to the rapid progress to coma within 1-2 hours. LCAD deficiency exhibits the highest accumulation of fatty acids along with marked increase of these substrates during catabolic stress and the lowest production rate of acetyl-CoA. These findings might confirm gestational loss to be the explanation that no human cases of LCAD deficiency have been described.ConclusionIn summary, this work provides a detailed kinetic model of mitochondrial metabolism with specific focus on fatty acid beta-oxidation to simulate and predict the dynamic response of that metabolic network in the context of human disease. Our findings offer insight into the disease process (e.g. rapid progress to coma) and might confirm new explanations (no human cases of LCAD deficiency), which can hardly be obtained from experimental data alone.

Project description:Mutations in nuclear genes encoding for mitochondrial proteins very long-chain acyl-CoA dehydrogenase (VLCAD) and trifunctional protein (TFP) cause rare autosomal recessive disorders. Studies in fibroblasts derived from patients with mutations in VLCAD and TFP exhibit mitochondrial defects. To gain insights on pathological changes that account for the mitochondrial deficits we performed quantitative proteomic, biochemical, and morphometric analyses in fibroblasts derived from subjects with three different VLCAD and three different TFP mutations. Proteomic data that was corroborated by antibody-based detection, indicated reduced levels of VLCAD and TFP protein in cells with VLCAD and TFP mutations respectively, which in part accounted for the diminished fatty acid oxidation capacity. Decreased mitochondrial respiratory capacity in cells with VLCAD and TFP mutations was quantified after glucose removal and cells with TFP mutations had lower levels of glycogen. Despite these energetic deficiencies, the cells with VLCAD and TFP mutations did not exhibit changes in mitochondria morphology, distribution, fusion and fission, quantified by either confocal or transmission electron microscopy and corroborated by proteomic and antibody-based protein analysis. Fibroblasts with VLCAD and to a lesser extend cells with TFP mutations had increased levels of mitochondrial respiratory chain proteins and proteins that facilitate the assembly of respiratory complexes. With the exception of reduced levels of catalase and glutathione S-transferase theta-1 in cells with TFP mutations, the levels of 45 proteins across all major intracellular antioxidant networks were similar between cells with VLCAD and TFP mutations and non-disease controls. Collectively the data indicate that despite the metabolic deficits, cells with VLCAD and TFP mutations maintain their proteomic integrity to preserve cellular and mitochondria architecture, support energy production and protect against oxidative stress.

Dataset Information

Functional analysis of molecular and pharmacological modulators of mitochondrial fatty acid oxidation.

Publications

Functional analysis of molecular and pharmacological modulators of mitochondrial fatty acid oxidation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets