Abstract

Apolipoprotein E4 (E4) and type 2 diabetes are major risk factors for cognitive decline and late onset Alzheimer’s disease (AD). E4-associated phenotypes and insulin resistance (IR) share several features and appear to interact in driving cognitive dysfunction. However, shared mechanisms that could explain their overlapping pathophysiology have yet to be found. We hypothesized that, compared to E3 mice, E4 mice would be more susceptible to the harmful cognitive effects of high fat diet (HFD)-induced IR due to apoE isoform-specific differences in brain metabolism. While both E3 and E4 mice fed HFD displayed impairments in peripheral metabolism and cognition, deficits in hippocampal-dependent spatial learning and memory were exaggerated in E4 mice. Combining genome-wide measures of DNA hydroxymethylation with comprehensive untargeted metabolomics, we identified novel alterations in purine metabolism, glutamate metabolism, and the pentose phosphate pathway. Finally, in E4 mice, the metabolic and cognitive deficiencies caused by HFD were rescued by switching to a low fat diet for one month, suggesting a functional role was associated with reversal of the same metabolic pathways described above. These results suggest a susceptibility of E4 carriers to metabolic impairments brought on by IR, and may guide development of novel therapies for cognitive decline and dementia.

Document Type

Article

Publication Date

3-8-2017

Notes/Citation Information

Published in Scientific Reports, v. 7, article no. 43701, p. 1-12.

© The Author(s) 2017

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Digital Object Identifier (DOI)

https://doi.org/10.1038/srep43701

Funding Information

L.A.J. was supported by NIEHS grant T32-ES07060, NIH grant T32-HL094294, NSF grant SMA-1408653, an OHSU Tartar Award, the Oregon Tax Check-off Program for Alzheimer’s Research administered by the Layton Aging & AD Center at OHSU, the Collins Medical Trust of Portland, OR, and the OHSU development account of J.R. N.A. was supported by NIH R21AG043857. J.F.S. was supported by NIH grant S10RR027878 and the OSU Mass Spectrometry Core Facility of the Environmental Health Sciences Center grant P30ES000210.

Related Content

Supplementary information accompanies this paper at http://www.nature.com/srep

srep43701-s1.pdf (2993 kB)
Supplementary Information

srep43701-s2.csv (1 kB)
Supplementary DataSet

srep43701-s3.csv (43 kB)
Supplementary Table1

srep43701-s4.csv (153 kB)
Supplementary Table2

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