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Restoring hippocampal glucose metabolism rescues cognition across Alzheimer disease pathologies

ABSTRACT: Impaired cerebral glucose metabolism is a pathologic feature of Alzheimer Disease (AD), and recent proteomic studies highlight a disruption of glial carbohydrate metabolism with disease progression. Here, we report that inhibition of indoleamine-2,3-dioxygenase 1 (IDO1), which metabolizes tryptophan to kynurenine (KYN) in the first step of the kynurenine pathway, rescues hippocampal memory function and plasticity in preclinical models of amyloid and tau pathology by restoring astrocytic metabolic support of neurons. Activation of IDO1 in astrocytes by amyloid-beta42 and tau oligomers, two major pathological effectors in AD, increases KYN and suppresses glycolysis in an AhR-dependent manner. Conversely, pharmacological IDO1 inhibition restores glycolysis and lactate production. In amyloid-producing APPSwe-PS1∆E9 and 5XFAD mice and in tau-producing P301S mice, IDO1 inhibition restores spatial memory and improves hippocampal glucose metabolism by metabolomic and MALDI-MS analyses. IDO1 blockade also rescues hippocampal long-term potentiation (LTP) in a monocarboxylate transporter (MCT)-dependent manner, suggesting that IDO1 activity disrupts astrocytic metabolic support of neurons. Indeed, in vitro mass-labeling of human astrocytes demonstrates that IDO1 regulates astrocyte generation of lactate that is then taken up by human neurons. In co-cultures of astrocytes and neurons derived from AD subjects, deficient astrocyte lactate transfer to neurons was corrected by IDO1 inhibition, resulting in improved neuronal glucose metabolism. Thus, IDO1 activity disrupts astrocytic metabolic support of neurons across both amyloid and tau pathologies and in a model of AD iPSC-derived neurons. These findings also suggest that IDO1 inhibitors developed for adjunctive therapy in cancer could be repurposed for treatment of amyloid- and tau-mediated neurodegenerative diseases.

ORGANISM(S): Homo sapiens

PROVIDER: GSE245823 | GEO | 2024/09/17

REPOSITORIES: GEO

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Project description:Background:Episodic memory loss is a prominent clinical manifestation of Alzheimer's disease(AD), which is closely related to tau pathology and hippocampal impairment. Given the heterogeneity of brain neurons, the precise role of different brain neurons in terms of their sensitivity to tau accumulation and contribution to AD-like social memory loss remains unclear and requires further investigation. Methods: We investigated the effects of AD-like tau pathology by Tandem mass tag proteomic and phosphoproteomic experiments, social behavioral test, hippocampal electrophysiology, immunofluorescent staining and in vivo optical fiber recording of GCaMP6f and iGABASnFR. Additionally, we utilized optogenetics and administered ursolic acid (UA) via oral gavage to examine their effects on social memory in mice. Results: By proteomic and phosphoproteomic analyses, we identified the characteristics of ventral hippocampal CA1 (vCA1) under both physiological conditions and AD-like tau pathology. As tau progressively accumulated, not dorsal CA1 (dCA1), but vCA1, especially its excitatory and PV neurons, were fully filled with mislocated and phosphorylated tau. Overexpression of human Tau (hTau) in excitatory and PV neurons respectively mimicked AD-like tau accumulation, significantly inhibited the neuronal excitability and suppressed distinct discrimination-associated firings of these neurons within vCA1. Photoactivating excitatory and PV neurons in vCA1 at specific rhythm and time-window efficiently ameliorated tau-impaired social memory. Significantly, one-month administration of UA efficiently decreased tau accumulation via autophagy in a TFEB (transcription factor EB)-dependent manner and recovered vCA1 microcircuit to ameliorate tau-impaired social memory.Conclusion: This study elucidated distinct protein and phosphoprotein networks between dCA1 and vCA1, and highlighted the susceptibility of the vCA1 microcircuit to AD-like tau accumulation. Notably, our novel findings regarding the efficacy of UA in reducing tau load and targeting the vCA1 microcircuit may provide a promising strategy for AD treatment in the future.

Project description:Aubert2005 - Interaction between astrocytes and neurons on energy metabolism Enocded non-curated model. Issues: - Confusing equations A.41 and A.42 - Missing values for parameters Vv,0 and dHb,0 This model is described in the article: Interaction between astrocytes and neurons studied using a mathematical model of compartmentalized energy metabolism. Aubert A, Costalat R. J. Cereb. Blood Flow Metab. 2005 Nov; 25(11): 1476-1490 Abstract: Understanding cerebral energy metabolism in neurons and astrocytes is necessary for the interpretation of functional brain imaging data. It has been suggested that astrocytes can provide lactate as an energy fuel to neurons, a process referred to as astrocyte-neuron lactate shuttle (ANLS). Some authors challenged this hypothesis, defending the classical view that glucose is the major energy substrate of neurons, at rest as well as in response to a stimulation. To test the ANLS hypothesis from a theoretical point of view, we developed a mathematical model of compartmentalized energy metabolism between neurons and astrocytes, adopting hypotheses highly unfavorable to ANLS. Simulation results can be divided between two groups, depending on the relative neuron versus astrocyte stimulation. If this ratio is low, ANLS is observed during all the stimulus and poststimulus periods (continuous ANLS), but a high ratio induces ANLS only at the beginning of the stimulus and during the poststimulus period (triphasic behavior). Finally, our results show that current experimental data on lactate kinetics are compatible with the ANLS hypothesis, and that it is essential to assess the neuronal and astrocytic NADH/NAD+ ratio changes to test the ANLS hypothesis. This model is hosted on BioModels Database and identified by: MODEL1411210000. To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

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Restoring hippocampal glucose metabolism rescues cognition across Alzheimer disease pathologies

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