3-hydroxypropionic Acids Research Articles

Abnormalities in subsets of B and T cells in Mexican patients with inborn errors of propionate metabolism: observations from a single-center case series.

Propionate inborn errors of metabolism (PIEM), including propionic (PA) and methylmalonic (MMA) acidemias, are inherited metabolic diseases characterized by toxic accumulation of propionic, 3-hydroxypropionic, methylcitric, and methylmalonic organic acids in biological fluids, causing recurrent acute metabolic acidosis events and encephalopathy, which can lead to fatal outcomes if managed inadequately. PIEM patients can develop hematological abnormalities and immunodeficiency, either as part of the initial clinical presentation or as chronic complications. The origin and characteristics of these abnormalities have been studied poorly. Thus, the aim of the present work was to evaluate and describe lymphoid, myeloid, and erythroid cell population profiles in a group of clinically stable PIEM patients. This was a retrospective study of 11 nonrelated Mexican PIEM patients. Clinical, biochemical, nutritional, hematological, and lymphocyte subsets were analyzed. Despite being considered clinically stable, 91% of patients had hematological or immunological abnormalities. The absolute lymphocyte subset counts were low in all patients but one, with CD4+ T-cell lymphopenia, being the most common one. Furthermore, of the 11 studied subjects, nine presented with a low CD4/CD8 ratio. Among the observed hematological alterations, bicytopenia was the most common (82%) one, followed by anemia (27%). Our results contribute to the landscape of immunological abnormalities observed previously in PIEM patients; these abnormalities can become a life-threatening chronic complications because of the increased risk of opportunistic diseases. These findings allow us to propose the inclusion of monitoring immune biomarkers, such as subsets of lymphocytes in the follow up of PIEM patients.

Disturbance of bioenergetics and calcium homeostasis provoked by metabolites accumulating in propionic acidemia in heart mitochondria of developing rats

Propionic acidemia is caused by lack of propionyl-CoA carboxylase activity. It is biochemically characterized by accumulation of propionic (PA) and 3-hydroxypropionic (3OHPA) acids and clinically by severe encephalopathy and cardiomyopathy. High urinary excretion of maleic acid (MA) and 2-methylcitric acid (2MCA) is also found in the affected patients. Considering that the underlying mechanisms of cardiac disease in propionic acidemia are practically unknown, we investigated the effects of PA, 3OHPA, MA and 2MCA (0.05–5 mM) on important mitochondrial functions in isolated rat heart mitochondria, as well as in crude heart homogenates and cultured cardiomyocytes. MA markedly inhibited state 3 (ADP-stimulated), state 4 (non-phosphorylating) and uncoupled (CCCP-stimulated) respiration in mitochondria supported by pyruvate plus malate or α-ketoglutarate associated with reduced ATP production, whereas PA and 3OHPA provoked less intense inhibitory effects and 2MCA no alterations at all. MA-induced impaired respiration was attenuated by coenzyme A supplementation. In addition, MA significantly inhibited α-ketoglutarate dehydrogenase activity. Similar data were obtained in heart crude homogenates and permeabilized cardiomyocytes. MA, and PA to a lesser degree, also decreased mitochondrial membrane potential (ΔΨm), NAD(P)H content and Ca2+ retention capacity, and caused swelling in Ca2+-loaded mitochondria. Noteworthy, ΔΨm collapse and mitochondrial swelling were fully prevented or attenuated by cyclosporin A and ADP, indicating the involvement of mitochondrial permeability transition. It is therefore proposed that disturbance of mitochondrial energy and calcium homeostasis caused by MA, as well as by PA and 3OHPA to a lesser extent, may be involved in the cardiomyopathy commonly affecting propionic acidemic patients.

Development and application of a transcriptional sensor for detection of heterologous acrylic acid production in E. coli

BackgroundAcrylic acid (AA) is a widely used commodity chemical derived from non-renewable fossil fuel sources. Alternative microbial-based production methodologies are being developed with the aim of providing “green” acrylic acid. These initiatives will benefit from component sensing tools that facilitate rapid and easy detection of in vivo AA production.ResultsWe developed a novel transcriptional sensor facilitating in vivo detection of acrylic acid (AA). RNAseq analysis of Escherichia coli exposed to sub-lethal doses of acrylic acid identified a selectively responsive promoter (PyhcN) that was cloned upstream of the eGFP gene. In the presence of AA, eGFP expression in E. coli cells harbouring the sensing construct was readily observable by fluorescence read-out. Low concentrations of AA (500 μM) could be detected whilst the closely related lactic and 3-hydroxy propionic acids failed to activate the sensor. We further used the developed AA-biosensor for in vivo FACS-based screening and identification of amidase mutants with improved catalytic properties for deamination of acrylamide to acrylic acid.ConclusionsThe transcriptional AA sensor developed in this study will benefit strain, enzyme and pathway engineering initiatives targeting the efficient formation of bio-acrylic acid.

Experimental evidence that maleic acid markedly compromises glutamate oxidation through inhibition of glutamate dehydrogenase and α-ketoglutarate dehydrogenase activities in kidney of developing rats.

Maleic acid (MA), which has been reported to be highly excreted in propionic acidemia (PAcidemia), was demonstrated to cause nephropathy by bioenergetics impairment and oxidative stress, but the effects on kidney mitochondrial respiration has not yet been properly investigated. Therefore, the present study investigated the effects of MA (0.05-5mM), as well as of propionic (PA) and 3-hydroxypropionic (3OHPA) acids (5mM) that accumulate in PAcidemia, on mitochondrial respiration supported by glutamate, glutamate plus malate or succinate in mitochondrial fractions and homogenates from rat kidney, as well as in permeabilized kidney cells. MA markedly decreased oxygen consumption in state 3 (ADP-stimulated) and uncoupled (CCCP-stimulated) respiration in glutamate and glutamate plus malate-respiring mitochondria, with less prominent effects when using succinate. We also found that PA significantly decreased state 3 and uncoupled respiration in glutamate- and glutamate plus malate-supported mitochondria, whereas 3OHPA provoked milder or no changes. Furthermore, glutamate dehydrogenase and α-ketoglutarate dehydrogenase activities necessary for glutamate oxidation were significantly inhibited by MA in a dose-dependent and competitive fashion. The MA-induced decrease of state 3 and uncoupled respiration found in mitochondrial fractions were also observed in homogenates and permeabilized renal cells that better mimic the in vivo cellular milieu. Taken together, our data indicate that MA, and PA to a lesser extent, disturb mitochondrial-oxidative metabolism in the kidney with the involvement of critical enzymes for glutamate oxidation. It is postulated that our present findings may be possibly involved in the chronic renal failure observed in patients with PAcidemia.

Mutations in ALDH6A1 encoding methylmalonate semialdehyde dehydrogenase are associated with dysmyelination and transient methylmalonic aciduria

BackgroundMethylmalonate semialdehyde dehydrogenase (MMSDH) deficiency is a rare autosomal recessive disorder with varied metabolite abnormalities, including accumulation of 3-hydroxyisobutyric, 3-hydroxypropionic, 3-aminoisobutyric and methylmalonic acids, as well as β-alanine. Existing reports describe a highly variable clinical and biochemical phenotype, which can make diagnosis a challenge. To date, only three reported cases have been confirmed at the molecular level, through identification of homozygous mutations in ALDH6A1, the gene encoding MMSDH. Confirmation by enzyme assay has until now not been possible, due to the extreme instability of the enzyme substrate.Methods and resultsWe report a child with severe developmental delays, abnormal myelination on brain MRI, and transient/variable elevations in lactate, methylmalonic acid, 3-hydroxyisobutyric and 3-aminoisobutyric acids. Compound heterozygous mutations were identified by exome sequencing and confirmed by Sanger sequencing within exon 6 (c.514 T > C; p. Tyr172His) and exon 12 (c.1603C > T; p. Arg535Cys) of ALDH6A1. The resulting amino acid changes, both occurring in residues conserved among mammals, are predicted to be damaging at the protein level. Subsequent MMSDH enzyme assay demonstrated reduced activity in patient fibroblasts, measuring 2.5 standard deviations below the mean.ConclusionsWe present the fourth reported case of MMSDH deficiency with confirmation at the molecular level, and expand on what is already an extremely variable clinical and biochemical phenotype. Furthermore, this is the first report to demonstrate a corresponding reduction in MMSDH enzyme activity. This report illustrates the emerging utilization of whole exome sequencing and variant data filtering using clinical data as an early tool in the diagnosis of rare and variable conditions.

Stereoselective binding of 2,3-substituted 3-hydroxypropionic acids on an immobilised human serum albumin chiral stationary phase: stereochemical characterisation and quantitative structure–retention relationship study

The binding characteristics of a series of 2,3-substituted 3-hydroxypropionic acids, with anti-inflammatory properties, bearing two chiral centres, were studied by HPLC upon HSA (human serum albumin)-based stationary phase. The compounds were analysed in their stereoisomeric erythro and threo forms and the chromatographic conditions for enantioseparation of the erythro and threo forms were studied on human serum albumin stationary phase. The enantiomer elution order was determined by injection of the enriched samples or by carrying out the CD spectra of each enantiomeric fraction. The absolute configuration of the single enantiomers was assigned on the basis of their CD spectra. A QSRR study was performed by subjecting the chromatographic data of the compounds to multiparameter regression analysis against various molecular descriptors to have insight into the chiral recognition mechanism. The lipophilicity appeared to be the most important parameter in determining the affinity to the protein, the compounds’ capacity factors being linearly correlated to the experimental RP-HPLC partition coefficients (log k′ w). The enantioselectivity factors ( α) related to the enantiomers of the erythro and threo forms were studied taking into consideration both the physico-chemical parameters and the conformational behaviour of the compounds.

Kinetics of Wet Oxidation of Propionic and 3-Hydroxypropionic Acids

Oxidation of aqueous solutions of 3-hydroxypropionic (3-HPA) and propionic acids (PA) was studied in a titanium high-pressure reactor at 280−310 °C using oxygen partial pressures between 10 and 45 bar. Oxidation of both acids was found to obey first-order kinetic with respect to their concentrations as well as to their lumped TOC concentrations. Oxidation rate revealed a half order dependence with respect to oxygen for oxidation of both acids. In the case of 3-HPA oxidation, the activation energy was found to be 135 kJ/mol, and it was 140 kJ/mol when lumped concentration TOC was used. The activation energy for PA oxidation is 150 kJ/mol, and it is slightly higher, 158 kJ/mol, for TOC reduction. Almost complete conversion of 3-HPA was achieved at 300 °C after 1 h, whereas 95% conversion of PA acid was obtained at 310 °C after 3 h. During oxidation of 3-HPA, 3-oxopropionic and acetic acids were identified as intermediate products. Oxidation of PA yielded acetic and formic acids as intermediates; at oxygen p...

Acids in chicory roots and malt

Acids known to be decomposition products of carbohydrates were quantified in raw, dried and roasted chicory roots and in dried and roasted barley malt by means of gas liquid chromatography/mass spectrometry and isotachophoresis. Acids derived from other educts will be dealt with in following papers. Of the acids found, eight are of the aldonic type, ten are deoxyaldonic, three are oxo acids, two are derivatives of furanoic acid, two are volatile acids and the others are methyl succinic and oxalic acid. Qualitatively, chicory and malt are composed of the same acids, but generally speaking the concentration of acids in chicory is higher. While in the dried educts only trace amounts can be detected, the concentration of acids increases upon roasting. In roasted chicory roots considerably high contents of acetic, formic, glycolic, pyruvic, lactic, metasaccharinic, oxalic, glyceric and 3-hydroxypropionic acids were quantified. 5-Hydroxymethyl-2-furanoic, 2,4-dihydroxybutyric, 3,4-dihydroxybutyric, arabonic, gluconic, ribonic, erythronic, threonic, 4-oxovaleric, methyl succinic, 2-furanoic, mannonic, 3-deoxypentonic, saccharinic, isosaccbarinic, methyl glyceric and 2-oxovaleric acids are minor compounds. In malt samples only acetic, pyruvic, formic, oxalic and lactic acids were detected in relatively high concentrations. Gluconic, 3,4-dihydroxybutyric, 3-hydroxypropionic, metasaccharinic, mannonic, glyceric, glycolic, 2,4-dihydroxybutyric, ribonic, threonic, 5-hydroxymethyl-2-furanoic, erythronic, 4-oxovaleric, 2-furanoic, saccharinic, methyl succinic, arabonic, 3-deoxypentonic, methyl glyceric, 2-oxovaleric and isosaccharinic acids are minor compounds

Studies on the metabolisms of fusaric acid(5-butylpyridine-2-carboxylic acid) aza-analogues

In order to estimate the generality of the chain elongation reaction observed on the metabolism of fusaric acid (5-butylpyridine-2-carboxylic acid) in rat liver, the metabolism of the following heteroaromatic carboxylic acids, 5-alkylpyrimidine-2-carboxylic acid (3a-d), 2-alkylpyrimidine-5-carboxylic acid (4a-d), 6-pentylpyridazine-3-carboxylic acid (5), and 5-pentylpyrazine-2-carboxylic acid (6), was investigated. Although 4a-d, 5, and 6 did not undergo the chain elongation, in the metabolites of 3a-d collected from the rat urine, pyrimidine-2-propionic acids, pyrimidine-2-acrylic acids, pyrimidine-2-(3-hydroxypropionic)acids, and pyrimidine-2-(3-oxopropionic)acids were detected together with the ω-oxidation products by gas chromatography-mass spectrometry technique. This is a rare example of chain elongation in drug matabolism as well as the case of 5-alkylpyridine-2-carboxylic acids.

Glutaric, 3-hydroxypropionic, and lactic aciduria with metabolic acidemia, following extensive small bowel resection

A patient with extensive small bowel resection as a neonate excretes glutaric, 3-hydroxypropionic, and lactic acids in a manner atypical for any recognized genetic metabolic disease. The organic aciduria varies with dietary intake: lactic acid predominates when he takes a high-carbohydrate, low-protein diet, and glutaric acid and products of aromatic amino acid catabolism dominate when protein intake increases. The association of 3-hydroxypropionic acid excretion with dietary intake is less clear. The available evidence is consistent with the hypothesis that the organic aciduria results from rapid transit and decreased absorption of ingested nutrients in his shortened small intestine, followed by bacterial metabolism of these substances in the colon, absorption of the metabolic products, and urinary excretion of those bacterial products which do not serve as intermediates in human metabolism.