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Paradoxical neuronal hyperexcitability in a mouse model of mitochondrial pyruvate import deficiency
Journal article   Open access   Peer reviewed

Paradoxical neuronal hyperexcitability in a mouse model of mitochondrial pyruvate import deficiency

Andres De la Rossa, Marine H. Laporte, Simone Astori, Thomas Marissal, Sylvie Montessuit, Preethi Sheshadri, Eva Ramos-Fernandez, Pablo Mendez, Abbas Khani, Charles Quairiaux, …
eLife, Vol.11, e72595
02/21/2022
DOI: 10.7554/eLife.72595.sa2
PMCID: PMC8860443
PMID: 35188099
url
https://doi.org/10.7554/eLife.72595.sa2View
Published (Version of record) Open Access

Abstract

Neuronal excitation imposes a high demand of ATP in neurons. Most of the ATP derives primarily from pyruvate-mediated oxidative phosphorylation, a process that relies on import of pyruvate into mitochondria occuring exclusively via the mitochondrial pyruvate carrier (MPC). To investigate whether deficient oxidative phosphorylation impacts neuron excitability, we generated a mouse strain carrying a conditional deletion of MPC1, an essential subunit of the MPC, specifically in adult glutamatergic neurons. We found that, despite decreased levels of oxidative phosphorylation and decreased mitochondrial membrane potential in these excitatory neurons, mice were normal at rest. Surprisingly, in response to mild inhibition of GABA mediated synaptic activity, they rapidly developed severe seizures and died, whereas under similar conditions the behavior of control mice remained unchanged. We report that neurons with a deficient MPC were intrinsically hyperexcitable as a consequence of impaired calcium homeostasis, which reduced M-type potassium channel activity. Provision of ketone bodies restored energy status, calcium homeostasis and M-channel activity and attenuated seizures in animals fed a ketogenic diet. Our results provide an explanation for the seizures that frequently accompany a large number of neuropathologies, including cerebral ischemia and diverse mitochondriopathies, in which neurons experience an energy deficit.
Biology Life Sciences & Biomedicine Life Sciences & Biomedicine - Other Topics Science & Technology

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