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@ARTICLE{Melo:141163,
author = {Melo, Daniela R and Mirandola, Sandra R and Assunção,
Nilson A and Castilho, Roger F},
title = {{M}ethylmalonate impairs mitochondrial respiration
supported by {NADH}-linked substrates: involvement of
mitochondrial glutamate metabolism.},
journal = {Journal of neuroscience research},
volume = {90},
number = {6},
issn = {0360-4012},
address = {New York, NY [u.a.]},
publisher = {Wiley-Liss},
reportid = {DZNE-2020-07485},
pages = {1190-1199},
year = {2012},
abstract = {The neurodegeneration that occurs in methylmalonic acidemia
is proposed to be associated with impairment of
mitochondrial oxidative metabolism resulting from
methylmalonate (MMA) accumulation. The present study
evaluated the effects of MMA on oxygen consumption by
isolated rat brain mitochondria in the presence of
NADH-linked substrates (α-ketoglutarate, citrate,
isocitrate, glutamate, malate, and pyruvate). Respiration
supported either by glutamate or glutamate plus malate was
significantly inhibited by MMA (1-10 mM), whereas no
inhibition was observed when a cocktail of NADH-linked
substrates was used. Measurements of glutamate transport
revealed that the inhibitory effect of MMA on respiration
maintained by this substrate is not due to inhibition of its
mitochondrial uptake. In light of this result, the effect of
MMA on the activity of relevant enzymes involved in
mitochondrial glutamate metabolism was investigated. MMA had
minor inhibitory effects on glutamate dehydrogenase and
aspartate aminotransferase, whereas α-ketoglutarate
dehydrogenase was significantly inhibited by this metabolite
(K(i) = 3.65 mM). Moreover, measurements of α-ketoglutarate
transport and mitochondrial MMA accumulation indicated that
MMA/α-ketoglutarate exchange depletes mitochondria from
this substrate, which may further contribute to the
inhibition of glutamate-sustained respiration. To study the
effect of chronic in vivo MMA treatment on mitochondrial
function, young rats were intraperitoneally injected with
MMA. No significant difference was observed in respiration
between isolated brain mitochondria from control and
MMA-treated rats, indicating that in vivo MMA treatment did
not lead to permanent mitochondrial respiratory defects.
Taken together, these findings indicate that the inhibitory
effect of MMA on mitochondrial oxidative metabolism can be
ascribed to concurrent inhibition of specific enzymes and
lower availability of respiratory substrates.},
keywords = {Amino Acid Transport System X-AG: metabolism / Analysis of
Variance / Animals / Animals, Newborn / Carboxy-Lyases:
metabolism / Citrate (si)-Synthase: metabolism /
Dose-Response Relationship, Drug / Glutamate Dehydrogenase:
metabolism / Glutamic Acid: metabolism / Ketoglutarate
Dehydrogenase Complex: metabolism / Ketoglutaric Acids:
metabolism / Methylmalonic Acid: metabolism / Methylmalonic
Acid: pharmacology / Mitochondria: drug effects /
Mitochondria: metabolism / Multienzyme Complexes: metabolism
/ Oxygen Consumption: drug effects / Prosencephalon: drug
effects / Prosencephalon: ultrastructure / Rats / Rats,
Wistar / Amino Acid Transport System X-AG (NLM Chemicals) /
Ketoglutaric Acids (NLM Chemicals) / Multienzyme Complexes
(NLM Chemicals) / Glutamic Acid (NLM Chemicals) /
Methylmalonic Acid (NLM Chemicals) / Ketoglutarate
Dehydrogenase Complex (NLM Chemicals) / Glutamate
Dehydrogenase (NLM Chemicals) / Citrate (si)-Synthase (NLM
Chemicals) / Carboxy-Lyases (NLM Chemicals) / aspartate
4-decarboxylase (NLM Chemicals)},
cin = {AG Alamoudi},
ddc = {570},
cid = {I:(DE-2719)1013012},
pnm = {341 - Molecular Signaling (POF3-341)},
pid = {G:(DE-HGF)POF3-341},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:22488725},
doi = {10.1002/jnr.23020},
url = {https://pub.dzne.de/record/141163},
}