Secondary mitochondrial dysfunction in propionic aciduria: a pathogenic role for endogenous mitochondrial toxins

Mitochondrial dysfunction during acute metabolic crises is considered an important pathomechanism in inherited disorders of propionate metabolism, i.e. propionic and methylmalonic acidurias. Biochemically, these disorders are characterized by accumulation of propionyl-CoA and metabolites of alternative propionate oxidation. In the present study, we demonstrate uncompetitive inhibition of PDHc (pyruvate dehydrogenase complex) by propionyl-CoA in purified porcine enzyme and in submitochondrial particles from bovine heart being in the same range as the inhibition induced by acetyl-CoA, the physiological product and known inhibitor of PDHc. Evaluation of similar monocarboxylic CoA esters showed a chain-length specificity for PDHc inhibition. In contrast with CoA esters, non-esterified fatty acids did not inhibit PDHc activity. In addition to PDHc inhibition, analysis of respiratory chain and tricarboxylic acid cycle enzymes also revealed an inhibition by propionyl-CoA on respiratory chain complex III and α-ketoglutarate dehydrogenase complex. To test whether impairment of mitochondrial energy metabolism is involved in the pathogenesis of propionic aciduria, we performed a thorough bioenergetic analysis in muscle biopsy specimens of two patients. In line with the in vitro results, oxidative phosphorylation was severely compromised in both patients. Furthermore, expression of respiratory chain complexes I–IV and the amount of mitochondrial DNA were strongly decreased, and ultrastructural mitochondrial abnormalities were found, highlighting severe mitochondrial dysfunction. In conclusion, our results favour the hypothesis that toxic metabolites, in particular propionyl-CoA, are involved in the pathogenesis of inherited disorders of propionate metabolism, sharing mechanistic similarities with propionate toxicity in micro-organisms.

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The multiple roles of the mitochondrion of the malarial parasite

Parasitology ◽

10.1017/s0031182004005888 ◽

2004 ◽

Vol 129 (5) ◽

pp. 511-524 ◽

Cited By ~ 50

Author(s):

J. KRUNGKRAI

Keyword(s):

Electron Transport ◽

Cytochrome C ◽

Transport System ◽

Antimalarial Drug ◽

Tricarboxylic Acid Cycle ◽

Coenzyme Q ◽

Complex Iii ◽

Electron Transport System ◽

Complex Ii ◽

Dehydrogenase Complex

Mitochondria of the malaria parasitePlasmodium falciparumare morphologically different between the asexual and sexual blood stages (gametocytes). In this paper recent findings of mitochondrial heterogeneity are reviewed based on their ultrastructural characteristics, metabolic activities and the differential expression of their genes in these 2 blood stages of the parasite. The existence of NADH dehydrogenase (complex I), succinate dehydrogenase (complex II), cytochrome c reductase (complex III) and cytochrome c oxidase (complex IV) suggests that the biochemically active electron transport system operates in this parasite. There is also an alternative electron transport branch pathway, including an anaerobic function of complex II. One of the functional roles of the mitochondrion in the parasite is the coordination of pyrimidine biosynthesis, the electron transport system and oxygen utilization via dihydroorotate dehydrogenase and coenzyme Q. Complete sets of genes encoding enzymes of the tricarboxylic acid cycle and the ATP synthase complex are predicted fromP. falciparumgenomics information. Other metabolic roles of this organelle include membrane potential maintenance, haem and coenzyme Q biosynthesis, and oxidative phosphorylation. Furthermore, the mitochondrion may be a chemotherapeutic target for antimalarial drug development. The antimalarial drug atovaquone targets the mitochondrion.

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Subunits Rip1p and Cox9p of the respiratory chain contribute to diclofenac-induced mitochondrial dysfunction

Microbiology ◽

10.1099/mic.0.044578-0 ◽

2011 ◽

Vol 157 (3) ◽

pp. 685-694 ◽

Cited By ~ 15

Author(s):

Jolanda S. van Leeuwen ◽

Rick Orij ◽

Marijke A. H. Luttik ◽

Gertien J. Smits ◽

Nico P. E. Vermeulen ◽

...

Keyword(s):

Mitochondrial Dysfunction ◽

Respiratory Chain ◽

Kidney Injury ◽

Complex Iii ◽

Enhanced Sensitivity ◽

In The Wild ◽

Liver And Kidney ◽

Ros Formation ◽

Cell Growth And Viability

The widely used drug diclofenac can cause serious heart, liver and kidney injury, which may be related to its ability to cause mitochondrial dysfunction. Using Saccharomyces cerevisiae as a model system, we studied the mechanisms of diclofenac toxicity and the role of mitochondria therein. We found that diclofenac reduced cell growth and viability and increased levels of reactive oxygen species (ROS). Strains increasingly relying on respiration for their energy production showed enhanced sensitivity to diclofenac. Furthermore, oxygen consumption was inhibited by diclofenac, suggesting that the drug inhibits respiration. To identify the site of respiratory inhibition, we investigated the effects of deletion of respiratory chain subunits on diclofenac toxicity. Whereas deletion of most subunits had no effect, loss of either Rip1p of complex III or Cox9p of complex IV resulted in enhanced resistance to diclofenac. In these deletion strains, diclofenac did not increase ROS formation as severely as in the wild-type. Our data are consistent with a mechanism of toxicity in which diclofenac inhibits respiration by interfering with Rip1p and Cox9p in the respiratory chain, resulting in ROS production that causes cell death.

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Bioenergetics in Glutaryl-Coenzyme A Dehydrogenase Deficiency

Journal of Biological Chemistry ◽

10.1074/jbc.m502845200 ◽

2005 ◽

Vol 280 (23) ◽

pp. 21830-21836 ◽

Cited By ~ 94

Author(s):

Sven W. Sauer ◽

Jürgen G. Okun ◽

Marina A. Schwab ◽

Linda R. Crnic ◽

Georg F. Hoffmann ◽

...

Keyword(s):

Respiratory Chain ◽

Dehydrogenase Deficiency ◽

Cell Damage ◽

Tricarboxylic Acid Cycle ◽

Tricarboxylic Acid ◽

Acid Oxidation ◽

Complex Activity ◽

Long Chain ◽

Dehydrogenase Complex ◽

Ketoglutarate Dehydrogenase

Inherited deficiency of glutaryl-CoA dehydrogenase results in an accumulation of glutaryl-CoA, glutaric, and 3-hydroxyglutaric acids. If untreated, most patients suffer an acute encephalopathic crisis and, subsequently, acute striatal damage being precipitated by febrile infectious diseases during a vulnerable period of brain development (age 3 and 36 months). It has been suggested before that some of these organic acids may induce excitotoxic cell damage, however, the relevance of bioenergetic impairment is not yet understood. The major aim of our study was to investigate respiratory chain, tricarboxylic acid cycle, and fatty acid oxidation in this disease using purified single enzymes and tissue homogenates from Gcdh-deficient and wild-type mice. In purified enzymes, glutaryl-CoA but not glutaric or 3-hydroxyglutaric induced an uncompetitive inhibition of α-ketoglutarate dehydrogenase complex activity. Notably, reduced activity of α-ketoglutarate dehydrogenase activity has recently been demonstrated in other neurodegenerative diseases, such as Alzheimer, Parkinson, and Huntington diseases. In contrast to α-ketoglutarate dehydrogenase complex, no direct inhibition of glutaryl-CoA, glutaric acid, and 3-hydroxyglutaric acid was found in other enzymes tested. In Gcdh-deficient mice, respiratory chain and tricarboxylic acid activities remained widely unaffected, virtually excluding regulatory changes in these enzymes. However, hepatic activity of very long-chain acyl-CoA dehydrogenase was decreased and concentrations of long-chain acylcarnitines increased in the bile of these mice, which suggested disturbed oxidation of long-chain fatty acids. In conclusion, our results demonstrate that bioenergetic impairment may play an important role in the pathomechanisms underlying neurodegenerative changes in glutaryl-CoA dehydrogenase deficiency.

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Neurotoxicity and underlying cellular changes of 21 mitochondrial respiratory chain inhibitors

Archives of Toxicology ◽

10.1007/s00204-020-02970-5 ◽

2021 ◽

Vol 95 (2) ◽

pp. 591-615

Author(s):

Johannes Delp ◽

Andrea Cediel-Ulloa ◽

Ilinca Suciu ◽

Petra Kranaster ◽

Barbara MA van Vugt-Lussenburg ◽

...

Keyword(s):

Mitochondrial Dysfunction ◽

Respiratory Chain ◽

Adverse Outcome ◽

Neuronal Cell ◽

Mitochondrial Respiratory Chain ◽

Complex Iii ◽

Adverse Outcome Pathway ◽

Assay Sensitivity ◽

Mitochondrial Respiratory

AbstractInhibition of complex I of the mitochondrial respiratory chain (cI) by rotenone and methyl-phenylpyridinium (MPP +) leads to the degeneration of dopaminergic neurons in man and rodents. To formally describe this mechanism of toxicity, an adverse outcome pathway (AOP:3) has been developed that implies that any inhibitor of cI, or possibly of other parts of the respiratory chain, would have the potential to trigger parkinsonian motor deficits. We used here 21 pesticides, all of which are described in the literature as mitochondrial inhibitors, to study the general applicability of AOP:3 or of in vitro assays that are assessing its activation. Five cI, three complex II (cII), and five complex III (cIII) inhibitors were characterized in detail in human dopaminergic neuronal cell cultures. The NeuriTox assay, examining neurite damage in LUHMES cells, was used as in vitro proxy of the adverse outcome (AO), i.e., of dopaminergic neurodegeneration. This test provided data on whether test compounds were unspecific cytotoxicants or specifically neurotoxic, and it yielded potency data with respect to neurite degeneration. The pesticide panel was also examined in assays for the sequential key events (KE) leading to the AO, i.e., mitochondrial respiratory chain inhibition, mitochondrial dysfunction, and disturbed proteostasis. Data from KE assays were compared to the NeuriTox data (AO). The cII-inhibitory pesticides tested here did not appear to trigger the AOP:3 at all. Some of the cI/cIII inhibitors showed a consistent AOP activation response in all assays, while others did not. In general, there was a clear hierarchy of assay sensitivity: changes of gene expression (biomarker of neuronal stress) correlated well with NeuriTox data; mitochondrial failure (measured both by a mitochondrial membrane potential-sensitive dye and a respirometric assay) was about 10–260 times more sensitive than neurite damage (AO); cI/cIII activity was sometimes affected at > 1000 times lower concentrations than the neurites. These data suggest that the use of AOP:3 for hazard assessment has a number of caveats: (i) specific parkinsonian neurodegeneration cannot be easily predicted from assays of mitochondrial dysfunction; (ii) deriving a point-of-departure for risk assessment from early KE assays may overestimate toxicant potency.

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Defects in the mitochondrial energy metabolism outside the respiratory chain and the pyruvate dehydrogenase complex

Detection of Mitochondrial Diseases ◽

10.1007/978-1-4615-6111-8_38 ◽

1997 ◽

pp. 243-247

Author(s):

Frans J. M. Trijbels ◽

Wim Ruitenbeek ◽

Marjan Huizing ◽

Udo Wendel ◽

Jan A. M. Smeitink ◽

...

Keyword(s):

Energy Metabolism ◽

Respiratory Chain ◽

Pyruvate Dehydrogenase ◽

Pyruvate Dehydrogenase Complex ◽

Mitochondrial Energy Metabolism ◽

Dehydrogenase Complex

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NAD + repletion produces no therapeutic effect in mice with respiratory chain complex III deficiency and chronic energy deprivation

The FASEB Journal ◽

10.1096/fj.201800090r ◽

2018 ◽

Vol 32 (11) ◽

pp. 5913-5926 ◽

Cited By ~ 9

Author(s):

Janne Purhonen ◽

Jayasimman Rajendran ◽

Saara Tegelberg ◽

Olli-Pekka Smolander ◽

Eija Pirinen ◽

...

Keyword(s):

Therapeutic Effect ◽

Respiratory Chain ◽

Chain Complex ◽

Complex Iii ◽

Respiratory Chain Complex ◽

Energy Deprivation

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Specific requirements of nonbilayer phospholipids in mitochondrial respiratory chain function and formation

Molecular Biology of the Cell ◽

10.1091/mbc.e15-12-0865 ◽

2016 ◽

Vol 27 (14) ◽

pp. 2161-2171 ◽

Cited By ~ 31

Author(s):

Charli D. Baker ◽

Writoban Basu Ball ◽

Erin N. Pryce ◽

Vishal M. Gohil

Keyword(s):

Respiratory Chain ◽

Mitochondrial Membrane ◽

Phospholipid Composition ◽

Mitochondrial Respiratory Chain ◽

Complex Iii ◽

Specific Requirement ◽

Transport Pathway ◽

Contact Sites ◽

Yeast Mutants ◽

Mitochondrial Respiratory

Mitochondrial membrane phospholipid composition affects mitochondrial function by influencing the assembly of the mitochondrial respiratory chain (MRC) complexes into supercomplexes. For example, the loss of cardiolipin (CL), a signature non–bilayer-forming phospholipid of mitochondria, results in disruption of MRC supercomplexes. However, the functions of the most abundant mitochondrial phospholipids, bilayer-forming phosphatidylcholine (PC) and non–bilayer-forming phosphatidylethanolamine (PE), are not clearly defined. Using yeast mutants of PE and PC biosynthetic pathways, we show a specific requirement for mitochondrial PE in MRC complex III and IV activities but not for their formation, whereas loss of PC does not affect MRC function or formation. Unlike CL, mitochondrial PE or PC is not required for MRC supercomplex formation, emphasizing the specific requirement of CL in supercomplex assembly. Of interest, PE biosynthesized in the endoplasmic reticulum (ER) can functionally substitute for the lack of mitochondrial PE biosynthesis, suggesting the existence of PE transport pathway from ER to mitochondria. To understand the mechanism of PE transport, we disrupted ER–mitochondrial contact sites formed by the ERMES complex and found that, although not essential for PE transport, ERMES facilitates the efficient rescue of mitochondrial PE deficiency. Our work highlights specific roles of non–bilayer-forming phospholipids in MRC function and formation.

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Mitochondrial function in flying honeybees (Apis mellifera): respiratory chain enzymes and electron flow from complex III to oxygen

Journal of Experimental Biology ◽

10.1242/jeb.203.5.905 ◽

2000 ◽

Vol 203 (5) ◽

pp. 905-911 ◽

Cited By ~ 9

Author(s):

R.K. Suarez ◽

J.F. Staples ◽

J.R. Lighton ◽

O. Mathieu-Costello

Keyword(s):

Surface Area ◽

Muscle Mass ◽

Respiratory Chain ◽

Mitochondrial Function ◽

Electron Flow ◽

Complex Iii ◽

High Mass ◽

Metabolic Rates ◽

Turnover Rates ◽

Respiratory Enzymes

The biochemical bases for the high mass-specific metabolic rates of flying insects remain poorly understood. To gain insights into mitochondrial function during flight, metabolic rates of individual flying honeybees were measured using respirometry, and their thoracic muscles were fixed for electron microscopy. Mitochondrial volume densities and cristae surface densities, combined with biochemical data concerning cytochrome content per unit mass, were used to estimate respiratory chain enzyme densities per unit cristae surface area. Despite the high content of respiratory enzymes per unit muscle mass, these are accommodated by abundant mitochondria and high cristae surface densities such that enzyme densities per unit cristae surface area are similar to those found in mammalian muscle and liver. These results support the idea that a unit area of mitochondrial inner membrane constitutes an invariant structural unit. Rates of O(2) consumption per unit cristae surface area are much higher than those estimated in mammals as a consequence of higher enzyme turnover rates (electron transfer rates per enzyme molecule) during flight. Cytochrome c oxidase, in particular, operates close to its maximum catalytic capacity (k(cat)). Thus, high flux rates are achieved via (i) high respiratory enzyme content per unit muscle mass and (ii) the operation of these enzymes at high fractional velocities.

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13C isotopomer model for estimation of anaplerotic substrate oxidation via acetyl-CoA

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1996.271.4.e788 ◽

1996 ◽

Vol 271 (4) ◽

pp. E788-E799 ◽

Cited By ~ 15

Author(s):

F. M. Jeffrey ◽

C. J. Storey ◽

A. D. Sherry ◽

C. R. Malloy

Keyword(s):

Biochemical Analysis ◽

Tricarboxylic Acid Cycle ◽

Tricarboxylic Acid ◽

Acetyl Coa ◽

Acid Cycle ◽

Propionate Metabolism ◽

13C Nuclear Magnetic Resonance ◽

Isotopomer Analysis ◽

Tricarboxylic Acid Cycle Intermediates ◽

Anaplerotic Pathway

A previous model using 13C nuclear magnetic resonance isotopomer analysis provided for direct measurement of the oxidation of 13C-enriched substrates in the tricarboxylic acid cycle and/or their entry via anaplerotic pathways. This model did not allow for recycling of labeled metabolites from tricarboxylic acid cycle intermediates into the acetyl-CoA pool. An extension of this model is now presented that incorporates carbon flow from oxaloacetate or malate to acetyl-CoA. This model was examined using propionate metabolism in the heart, in which previous observations indicated that all of the propionate consumed was oxidized to CO2 and water. Application of the new isotopomer model shows that 2 mM [3-13C]propionate entered the tricarboxylic acid cycle as succinyl-CoA (an anaplerotic pathway) at a rate equal to 52% of tricarboxylic acid cycle turnover and that all of this carbon entered the acetyl-CoA pool and was oxidized. This was verified using standard biochemical analysis; from the rate (mumol.min-1.g dry wt-1) of propionate uptake (4.0 +/- 0.7), the estimated oxygen consumption (24.8 +/- 5) matched that experimentally determined (24.4 +/- 3).

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