Bioenergetics in glutaryl-coenzyme A dehydrogenase deficiency: a role for glutaryl-coenzyme A.
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 alpha-ketoglutarate dehydrogenase complex activity. Notably, reduced activity of alpha-ketoglutarate dehydrogenase activity has recently been demonstrated in other neurodegenerative diseases, such as Alzheimer, Parkinson, and Huntington diseases. In contrast to alpha-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.
Sauer
Sven W
SW
Department of General Pediatrics, Division of Inborn Metabolic Diseases, University Children's Hospital of Heidelberg, Im Neuenheimer Feld 150, D-69120 Heidelberg, Germany.
Okun
Jürgen G
JG
Schwab
Marina A
MA
Crnic
Linda R
LR
Hoffmann
Georg F
GF
Goodman
Stephen I
SI
Koeller
David M
DM
Kölker
Stefan
S
D000154:Aconitate Hydratase / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000196:embryology / Q000378:metabolism; D002417:Cattle; D002952:Citric Acid Cycle; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000378:metabolism; D050770:Glutaryl-CoA Dehydrogenase; D005978:Glutathione / Q000378:metabolism; D007521:Isocitrate Dehydrogenase / Q000378:metabolism; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism; D007658:Ketone Oxidoreductases / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009206:Myocardium / Q000378:metabolism; D019636:Neurodegenerative Diseases / Q000473:pathology; D009474:Neurons / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000172:deficiency*; D010100:Oxygen / Q000378:metabolism; D013053:Spectrophotometry
D005227:Fatty Acids; D007521:Isocitrate Dehydrogenase; D007658:Ketone Oxidoreductases; C053164:pyruvate dehydrogenase (NADP+); D007655:Ketoglutarate Dehydrogenase Complex; D044925:Oxidoreductases Acting on CH-CH Group Donors; D050770:Glutaryl-CoA Dehydrogenase; D008058:Dihydrolipoamide Dehydrogenase; D000154:Aconitate Hydratase; D005978:Glutathione; D010100:Oxygen