Publication
Title
CSF biomarker analysis of ABCA7 mutation carriers suggests altered APP processing and reduced inflammatory response
Author
Abstract
Background The Alzheimer's disease (AD) risk gene ABCA7 has suggested functions in lipid metabolism and the immune system. Rare premature termination codon (PTC) mutations and an expansion of a variable number of tandem repeats (VNTR) polymorphism in the gene, both likely cause a lower ABCA7 expression and hereby increased risk for AD. However, the exact mechanism of action remains unclear. By studying CSF biomarkers reflecting different types of AD-related pathological processes, we aim to get a better insight in those processes and establish a biomarker profile of mutation carriers.Methods The study population consisted of 229 AD patients for whom CSF was available and ABCA7 sequencing and VNTR genotyping had been performed. This included 28 PTC mutation and 16 pathogenic expansion carriers. CSF levels of A beta(1-42), A beta(1-40), P-tau(181), T-tau, sAPP alpha, sAPP beta, YKL-40, and hFABP were determined using ELISA and Meso Scale Discovery assays. We compared differences in levels of these biomarkers and the A beta ratio between AD patients with or without an ABCA7 PTC mutation or expansion using linear regression on INT-transformed data with APOE-status, age and sex as covariates.Results Carriers of ABCA7 expansion mutations had significantly lower A beta(1-42) levels (P = 0.022) compared with non-carrier patients. The effect of the presence of ABCA7 mutations on CSF levels was especially pronounced in APOE epsilon 4-negative carriers. In addition, VNTR expansion carriers had reduced A beta(1-40) (P = 0.023), sAPP alpha (P = 0.047), sAPP beta (P = 0.016), and YKL-40 (P = 0.0036) levels.Conclusions Our results are suggestive for an effect on APP processing by repeat expansions given the changes in the amyloid-related CSF biomarkers that were found in carriers. The decrease in YKL-40 levels in expansion carriers moreover suggests that these patients potentially have a reduced inflammatory response to AD damage. Moreover, our findings suggest the existence of a mechanism, independent of lowered expression, affecting neuropathology in expansion carriers.
Language
English
Source (journal)
Alzheimer's research & therapy
Publication
2023
ISSN
1758-9193
DOI
10.1186/S13195-023-01338-Y
Volume/pages
15 :1 (2023) , p. 1-13
Article Reference
195
ISI
001103053000001
Pubmed ID
37946268
Full text (Publisher's DOI)
Full text (open access)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
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Creation 04.12.2023
Last edited 06.12.2023
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