Ammonium accumulation is a primary effect of 2-methylcitrate exposure in an in vitro model for brain damage in methylmalonic aciduria.

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State: Public
Version: Final published version
Serval ID
serval:BIB_1AC5AEC0C198
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Ammonium accumulation is a primary effect of 2-methylcitrate exposure in an in vitro model for brain damage in methylmalonic aciduria.
Journal
Molecular genetics and metabolism
Author(s)
Cudré-Cung H.P., Zavadakova P., do Vale-Pereira S., Remacle N., Henry H., Ivanisevic J., Tavel D., Braissant O., Ballhausen D.
ISSN
1096-7206 (Electronic)
ISSN-L
1096-7192
Publication state
Published
Issued date
09/2016
Peer-reviewed
Oui
Volume
119
Number
1-2
Pages
57-67
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Abstract
Using 3D organotypic rat brain cell cultures in aggregates we recently identified 2-methylcitrate (2-MCA) as the main toxic metabolite for developing brain cells in methylmalonic aciduria. Exposure to 2-MCA triggered morphological changes and apoptosis of brain cells. This was accompanied by increased ammonium and decreased glutamine levels. However, the sequence and causal relationship between these phenomena remained unclear. To understand the sequence and time course of pathogenic events, we exposed 3D rat brain cell aggregates to different concentrations of 2-MCA (0.1, 0.33 and 1.0mM) from day in vitro (DIV) 11 to 14. Aggregates were harvested at different time points from DIV 12 to 19. We compared the effects of a single dose of 1mM 2-MCA administered on DIV 11 to the effects of repeated doses of 1mM 2-MCA. Pan-caspase inhibitors Z-VAD FMK or Q-VD-OPh were used to block apoptosis. Ammonium accumulation in the culture medium started within few hours after the first 2-MCA exposure. Morphological changes of the developing brain cells were already visible after 17h. The highest rate of cleaved caspase-3 was observed after 72h. A dose-response relationship was observed for all effects. Surprisingly, a single dose of 1mM 2-MCA was sufficient to induce all of the biochemical and morphological changes in this model. 2-MCA-induced ammonium accumulation and morphological changes were not prevented by concomitant treatment of the cultures with pan-caspase inhibitors Z-VAD FMK or Q-VD-OPh: ammonium increased rapidly after a single 1mM 2-MCA administration even after apoptosis blockade. We conclude that following exposure to 2-MCA, ammonium production in brain cell cultures is an early phenomenon, preceding cell degeneration and apoptosis, and may actually be the cause of the other changes observed. The fact that a single dose of 1mM 2-MCA is sufficient to induce deleterious effects over several days highlights the potential damaging effects of even short-lasting metabolic decompensations in children affected by methylmalonic aciduria.

Keywords
Amino Acid Chloromethyl Ketones/pharmacology, Amino Acid Metabolism, Inborn Errors/chemically induced, Amino Acid Metabolism, Inborn Errors/metabolism, Amino Acid Metabolism, Inborn Errors/physiopathology, Ammonium Compounds/metabolism, Ammonium Compounds/toxicity, Animals, Apoptosis/drug effects, Brain Injuries/chemically induced, Brain Injuries/metabolism, Brain Injuries/pathology, Caspase 3/metabolism, Cell Culture Techniques, Citrates/toxicity, Culture Media/chemistry, Glutamine/metabolism, Humans, Neurons/drug effects, Neurons/metabolism, Neurons/pathology, Quinolines/pharmacology, Rats, 2-Methyl citric acid or 2-methylcitrate, Ammonium, Apoptosis, Brain development, Methylmalonic aciduria, Neurotoxicity
Pubmed
Web of science
Open Access
Yes
Create date
09/09/2016 8:52
Last modification date
20/08/2019 12:51
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