Significance of bound glutarate in the diagnosis of glutaric aciduria type I

Ribes, Antònia; Riudor, E.; Briones, Paz; Christensen, Ernst; Campistol, Jaume; Millington, David S.

doi:10.1007/bf02435978

Cited by 27 publications

(10 citation statements)

References 7 publications

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“…Organic acids from 500 µl of supernatants were analyzed by gas chromatography-mass spectrometry as TMS-derivates, as previously described [29], but using 7 µl of 5 mM undecanodioic acid as the internal standard and SIM mode monitoring ions 191 and 345 for the detection of β-hydroxybutyric and undecanodioic acids respectively.…”

Section: Methodsmentioning

confidence: 99%

Fatty Acid Transport Protein 1 (FATP1) Localizes in Mitochondria in Mouse Skeletal Muscle and Regulates Lipid and Ketone Body Disposal

et al. 2014

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FATP1 mediates skeletal muscle cell fatty acid import, yet its intracellular localization and metabolic control role are not completely defined. Here, we examine FATP1 localization and metabolic effects of its overexpression in mouse skeletal muscle. The FATP1 protein was detected in mitochondrial and plasma membrane fractions, obtained by differential centrifugation, of mouse gastrocnemius muscle. FATP1 was most abundant in purified mitochondria, and in the outer membrane and soluble intermembrane, but not in the inner membrane plus matrix, enriched subfractions of purified mitochondria. Immunogold electron microscopy localized FATP1-GFP in mitochondria of transfected C2C12 myotubes. FATP1 was overexpressed in gastrocnemius mouse muscle, by adenovirus-mediated delivery of the gene into hindlimb muscles of newborn mice, fed after weaning a chow or high-fat diet. Compared to GFP delivery, FATP1 did not alter body weight, serum fed glucose, insulin and triglyceride levels, and whole-body glucose tolerance, in either diet. However, fatty acid levels were lower and β-hydroxybutyrate levels were higher in FATP1- than GFP-mice, irrespective of diet. Moreover, intramuscular triglyceride content was lower in FATP1- versus GFP-mice regardless of diet, and β-hydroxybutyrate content was unchanged in high-fat-fed mice. Electroporation-mediated FATP1 overexpression enhanced palmitate oxidation to CO2, but not to acid-soluble intermediate metabolites, while CO2 production from β-hydroxybutyrate was inhibited and that from glucose unchanged, in isolated mouse gastrocnemius strips. In summary, FATP1 was localized in mitochondria, in the outer membrane and intermembrane parts, of mouse skeletal muscle, what may be crucial for its metabolic effects. Overexpressed FATP1 enhanced disposal of both systemic fatty acids and intramuscular triglycerides. Consistently, it did not contribute to the high-fat diet-induced metabolic dysregulation. However, FATP1 lead to hyperketonemia, likely secondary to the sparing of ketone body oxidation by the enhanced oxidation of fatty acids.

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Section: Methodsmentioning

confidence: 99%

Fatty Acid Transport Protein 1 (FATP1) Localizes in Mitochondria in Mouse Skeletal Muscle and Regulates Lipid and Ketone Body Disposal

et al. 2014

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“…(2) Recently, it has been speculated that the number of group 2 patients was probably small (3), but this is not the case in our population, where 40% of patients were found to belong to this group. Whether this is a particular genetic characteristic of our population or reflects the results of ongoing attempts to improve diagnosis (18,22,23,47) remains to be established. (3) The knowledge of GA I genotypes might be useful for prenatal diagnosis, particularly for families with high residual enzyme activity.…”

Section: Busquets Et Almentioning

confidence: 99%

Glutaryl-CoA Dehydrogenase Deficiency in Spain: Evidence of Two Groups of Patients, Genetically, and Biochemically Distinct

Busquets¹,

Merinero²,

et al. 2000

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Glutaryl-CoA dehydrogenase (GCDH) deficiency causes glutaric aciduria type I (GA I), an inborn error of metabolism that is characterized clinically by dystonia and dyskinesia and pathologically by neural degeneration of the caudate and putamen. Studies of metabolite excretion allowed us to categorize 43 GA I Spanish patients into two groups: group 1 (26 patients), those presenting with high excretion of both glutarate and 3-hydroxyglutarate, and group 2 (17 patients), those who might not be detected by routine urine organic acid analysis because glutarate might be normal and 3-hydroxyglutarate only slightly higher than controls. Single-strand conformation polymorphism (SSCP) screening and sequence analysis of the 11 exons and the corresponding intron boundaries of the GCDH gene allowed us to identify 13 novel and 10 previously described mutations. The most frequent mutations in group 1 were A293T and R402W with an allele frequency of 30% and 28%, respectively. These two mutations were also found in group 2, but always in heterozygosity, in particular in combination with mutations V400M or R227P. Interestingly, mutations V400M and R227P were only found in group 2, and at least one of these mutations was found in 11 of 15 unrelated alleles, accounting together for 53% of the mutant alleles in group 2. Therefore, it seems clear that two genetically and biochemically distinct groups of patients exist. The severity of the clinical phenotype seems to be closely linked to the development of encephalopathic crises rather than to residual enzyme activity or genotype. Comparison of GCDH protein with other acyl-CoA dehydrogenases (whose x-ray crystal structure has been determined) reveals that most of the mutations identified in GCDH protein seem to affect folding and tetramerization, as has been described for a number of mutations affecting mitochondrial ␤-oxidation acyl-CoA dehydrogenases.

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“…The sample was then heated at 60°C for 30 min, and pH was adjusted by adding 1 ml of 6 N HCl. Sequential extractions were carried out as described (18) with the exception that samples were extracted twice with 2 ml of diethyl ether and twice with 2 ml of ethyl acetate. 6 l of 5 mM undecanoic acid was added at the collection tube to serve as an internal standard of the procedure.…”

Section: Methodsmentioning

confidence: 99%

Extended Ischemia Prevents HIF1α Degradation at Reoxygenation by Impairing Prolyl-hydroxylation

Serra-Pérez

Planas

Núñez-O'Mara

et al. 2010

Journal of Biological Chemistry

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Hypoxia-inducible factor (HIF) is a heterodimeric transcription factor that activates the cellular response to hypoxia. The HIF1␣ subunit is constantly synthesized and degraded under normoxia, but degradation is rapidly inhibited when oxygen levels drop. Oxygen-dependent hydroxylation by prolyl-4-hydroxylases (PHD) mediates HIF1␣ proteasome degradation. Brain ischemia limits the availability not only of oxygen but also of glucose. We hypothesized that this circumstance could have a modulating effect on HIF. We assessed the separate involvement of oxygen and glucose in HIF1␣ regulation in differentiated neuroblastoma cells subjected to ischemia. We report higher transcriptional activity and HIF1␣ expression under oxygen deprivation in the presence of glucose (OD), than in its absence (oxygen and glucose deprivation, OGD). Unexpectedly, HIF1␣ was not degraded at reoxygenation after an episode of OGD. This was not due to impairment of proteasome function, but was associated with lower HIF1␣ hydroxylation. Krebs cycle metabolites fumarate and succinate are known inhibitors of PHD, while ␣-ketoglutarate is a co-substrate of the reaction. Lack of HIF1␣ degradation in the presence of oxygen was accompanied by a very low ␣-ketoglutarate/fumarate ratio. Furthermore, treatment with a fumarate analogue prevented HIF1␣ degradation under normoxia. In all, our data suggest that postischemic metabolic alterations in Krebs cycle metabolites impair HIF1␣ degradation in the presence of oxygen by decreasing its hydroxylation, and highlight the involvement of metabolic pathways in HIF1␣ regulation besides the well known effects of oxygen.The hypoxia-inducible transcription factor (HIF) 5 is expressed at very low levels in cells under normal oxygen tension, but is rapidly induced upon exposure to hypoxia (1), triggering the activation of a genetic program that enables the metabolic adaptation of cells (2). HIF is a heterodimeric factor composed of a hypoxia-regulated ␣-subunit (HIF1␣ or HIF2␣) and constitutively expressed HIF1␤ (also known as aryl hydrocarbon receptor nuclear translocator, ARNT) (2). Although the ␣-subunit is constantly transcribed and translated, it is also degraded in an oxygen-dependent mechanism. It is only with dwindling oxygen levels that HIF1␣ or HF2␣ expression is readily detected (3). In the presence of oxygen, HIF prolyl-hydroxylases (PHD) hydroxylate two proline residues (positions 402 and 564 in human HIF1␣), in a reaction that requires molecular oxygen and ␣-ketoglutarate as co-substrates (4). These hydroxyproline residues are recognized by the Von Hippel-Lindau tumor suppressor protein (pVHL), one of the components of a E3 ubiquitin-ligase complex that also contains elongins B and C, cullin2, and Rbx, which conjugates ubiquitin to HIF␣ (4, 5). This results in the oxygen-dependent targeting of HIF␣ to the proteasome. Decreased oxygen concentration results in impaired prolyl-hydroxylation, reduced targeting of HIF␣ to the proteasome and the accumulation of HIF in the nucleus, where it activates a pleth...

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Significance of bound glutarate in the diagnosis of glutaric aciduria type I

Cited by 27 publications

References 7 publications

Fatty Acid Transport Protein 1 (FATP1) Localizes in Mitochondria in Mouse Skeletal Muscle and Regulates Lipid and Ketone Body Disposal

Fatty Acid Transport Protein 1 (FATP1) Localizes in Mitochondria in Mouse Skeletal Muscle and Regulates Lipid and Ketone Body Disposal

Glutaryl-CoA Dehydrogenase Deficiency in Spain: Evidence of Two Groups of Patients, Genetically, and Biochemically Distinct

Extended Ischemia Prevents HIF1α Degradation at Reoxygenation by Impairing Prolyl-hydroxylation

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