title: Dietary energy substrates reverse early neuronal hyperactivity in a mouse model of Alzheimer's disease.
abstract: Deficient energy metabolism and network hyperactivity are the early symptoms of Alzheimer's disease (AD). In this study, we show that administration of exogenous oxidative energy substrates (OES) corrects neuronal energy supply deficiency that reduces the amyloid-beta-induced abnormal neuronal activity in vitro and the epileptic phenotype in AD model in vivo. In vitro, acute application of protofibrillar amyloid-β1-42 (Aβ1-42) induced aberrant network activity in wild-type hippocampal slices that was underlain by depolarization of both the neuronal resting membrane potential and GABA-mediated current reversal potential. Aβ1-42 also impaired synaptic function and long-term potentiation. These changes were paralleled by clear indications of impaired energy metabolism, as indicated by abnormal NAD(P)H signaling induced by network activity. However, when glucose was supplemented with OES pyruvate and 3-beta-hydroxybutyrate, Aβ1-42 failed to induce detrimental changes in any of the above parameters. We administered the same OES as chronic supplementation to a standard diet to APPswe/PS1dE9 transgenic mice displaying AD-related epilepsy phenotype. In the ex-vivo slices, we found neuronal subpopulations with significantly depolarized resting and GABA-mediated current reversal potentials, mirroring abnormalities we observed under acute Aβ1-42 application. Ex-vivo cortex of transgenic mice fed with standard diet displayed signs of impaired energy metabolism, such as abnormal NAD(P)H signaling and strongly reduced tolerance to hypoglycemia. Transgenic mice also possessed brain glycogen levels twofold lower than those of wild-type mice. However, none of the above neuronal and metabolic dysfunctions were observed in transgenic mice fed with the OES-enriched diet. In vivo, dietary OES supplementation abated neuronal hyperexcitability, as the frequency of both epileptiform discharges and spikes was strongly decreased in the APPswe/PS1dE9 mice placed on the diet. Altogether, our results suggest that early AD-related neuronal malfunctions underlying hyperexcitability and energy metabolism deficiency can be prevented by dietary supplementation with native energy substrates.
authors.affiliation: Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden.
authors.forename: Misha
authors.initials: M
authors.lastname: Zilberter
authors.forename: Anton
authors.initials: A
authors.lastname: Ivanov
authors.forename: Sofya
authors.initials: S
authors.lastname: Ziyatdinova
authors.forename: Marat
authors.initials: M
authors.lastname: Mukhtarov
authors.forename: Anton
authors.initials: A
authors.lastname: Malkov
authors.forename: Alan
authors.initials: A
authors.lastname: Alpár
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Tortoriello
authors.forename: Catherine H
authors.initials: CH
authors.lastname: Botting
authors.forename: Lívia
authors.initials: L
authors.lastname: Fülöp
authors.forename: Alex A
authors.initials: AA
authors.lastname: Osypov
authors.forename: Asla
authors.initials: A
authors.lastname: Pitkänen
authors.forename: Heikki
authors.initials: H
authors.lastname: Tanila
authors.forename: Tibor
authors.initials: T
authors.lastname: Harkany
authors.forename: Yuri
authors.initials: Y
authors.lastname: Zilberter
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000008:administration & dosage / Q000494:pharmacology; D000544:Alzheimer Disease / Q000378:metabolism* / Q000503:physiopathology*; D016229:Amyloid beta-Peptides / Q000378:metabolism; D016564:Amyloid beta-Protein Precursor / Q000235:genetics*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002555:Cerebrospinal Fluid; D004032:Diet; D004734:Energy Metabolism; D005260:Female; D006624:Hippocampus / Q000378:metabolism / Q000503:physiopathology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009249:NADP / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D053764:Presenilin-1 / Q000235:genetics*; D019289:Pyruvic Acid / Q000008:administration & dosage / Q000494:pharmacology; D015398:Signal Transduction; D013569:Synapses / Q000502:physiology
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D053764:Presenilin-1; D009249:NADP; D019289:Pyruvic Acid; D020155:3-Hydroxybutyric Acid