Human Apolipoprotein E Genotype Differentially Affects Olfactory Behavior and Sensory Physiology in Mice
Brett S East, Gloria Fleming, Kathy Peng, Jonas K Olofsson, Efrat Levy, Paul M Mathews, Donald A Wilson. Neuroscience, 2018-04-18
Topic: Genetics and APOE
Apolipoprotein E (ApoE) is an important lipid carrier in both the periphery and the brain. The ApoE ε4 allele (ApoE4) is the single most important genetic risk-factor for Alzheimer's disease (AD) while the ε2 allele (ApoE2) is associated with a lower risk of AD-related neurodegeneration compared to the most common variant, ε3 (ApoE3). ApoE genotype affects a variety of neural circuits; however, the olfactory system appears to provide early biomarkers of ApoE genotype effects. Here, we directly compared olfactory behavior and olfactory system physiology across all three ApoE genotypes in 6-month- and 12-month-old mice with targeted replacement for the human ApoE2, ApoE3, or ApoE4 genes. Odor investigation and habituation were assessed, along with, olfactory bulb and piriform cortical local field potential activity. The results demonstrate that while initial odor investigation was unaffected by ApoE genotype, odor habituation was impaired in E4 relative to E2 mice, with E3 mice intermediate in function. There was also significant deterioration of odor habituation from 6 to 12 months of age regardless of the ApoE genotype. Olfactory system excitability and odor responsiveness were similarly determined by ApoE genotype, with an ApoE4 > ApoE3 > ApoE2 excitability ranking. Although motivated behavior is influenced by many processes, hyper-excitability of ApoE4 mice may contribute to impaired odor habituation, while hypo-excitability of ApoE2 mice may contribute to its protective effects. Given that these ApoE mice do not have AD pathology, our results demonstrate how ApoE affects the olfactory system at early stages, prior to the development of AD.
Key findings
- The ApoE ε4 allele (ApoE4) is the single most important genetic risk-factor for Alzheimer's disease (AD) while the ε2 allele (ApoE2) is associated with a lower risk of AD-related neurodegeneration compared to the most common variant, ε3 (ApoE3).
- The results demonstrate that while initial odor investigation was unaffected by ApoE genotype, odor habituation was impaired in E4 relative to E2 mice, with E3 mice intermediate in function.
- There was also significant deterioration of odor habituation from 6 to 12 months of age regardless of the ApoE genotype.
- Given that these ApoE mice do not have AD pathology, our results demonstrate how ApoE affects the olfactory system at early stages, prior to the development of AD.
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Study details
- Evidence strengthLow
How this study scored 39/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported and randomised / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record, multi-centre collaboration and free to read, so those were left out: it earned 22 of the 56 points we could judge it on, which is 39 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Neuroscience) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 2 / 5 | 2018 — within 10 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Laboratory or animal study (title names “mice”) — scores zero |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 29678753) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 22 / 56 | Scored on 10 of 20 parts. We have no data for the rest, so they are left out: 22 of the 56 points we could judge it on is 39 out of 100. |
| Total | 39 / 100 | — |
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record names 7 authors; APA and Vancouver show the first six, BibTeX and the downloads carry all of them. Check the citation against the original before you use it.
APA 7th
East, B. S., Fleming, G., Peng, K., Olofsson, J. K., Levy, E., Mathews, P. M., et al. (2018). Human Apolipoprotein E Genotype Differentially Affects Olfactory Behavior and Sensory Physiology in Mice. Neuroscience. https://doi.org/10.1016/j.neuroscience.2018.04.009
Vancouver
East BS, Fleming G, Peng K, Olofsson JK, Levy E, Mathews PM, et al. Human Apolipoprotein E Genotype Differentially Affects Olfactory Behavior and Sensory Physiology in Mice. Neuroscience. 2018. doi:10.1016/j.neuroscience.2018.04.009. PMID: 29678753.
BibTeX
@article{east2018-29678753,
author = {East, Brett S and Fleming, Gloria and Peng, Kathy and Olofsson, Jonas K and Levy, Efrat and Mathews, Paul M and Wilson, Donald A},
title = {{Human Apolipoprotein E Genotype Differentially Affects Olfactory Behavior and Sensory Physiology in Mice}},
journal = {Neuroscience},
year = {2018},
doi = {10.1016/j.neuroscience.2018.04.009},
pmid = {29678753},
url = {https://doi.org/10.1016/j.neuroscience.2018.04.009}
}
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