Sentinel Biomarkers of apoE and APP Pathway Alterations in Alzheimer’s Disease and Their Validation in Cellular Models (CHIVAT‑AD)

Over the past years, we have investigated alterations in several key molecular processes involved in Alzheimer’s disease (AD), particularly the apolipoprotein E (apoE) signaling pathway and the metabolism of the amyloid precursor protein (APP). Our primary approach has been the analysis of brain and CSF extracts from patients with AD. Here, we propose a deeper development of the biomarker‑oriented component and the validation of our findings in human cellular models, specifically iPS‑derived cells, which will enable a more accurate interpretation of the detected alterations.
This iPSC model will be implemented using co‑cultures that combine isogenic variant and knockout lines for APOE, which will be highly valuable for deciphering neuron–glia interactions, particularly in the context of defective apoE signaling, dysregulated tau hyperphosphorylation, and pathological β‑amyloid processing. We will also validate, using iPSCs generated from a patient carrying an ADAM10 mutation, the relevance of α‑secretase insufficiency.
More specifically, we will focus on studying the levels of apoE species and their (co)receptors (apoER2, LRP3, TREM2, SORL1, NMDA‑R), APP (glycosylation and fragmentation), as well as secretases (ADAM10, meprin‑β, BACE1, PS1 and their interrelationships). Electrophoretic analyses combined with antibodies targeting distinct domains will allow us to discriminate full‑length proteins from fragments. Glycosylation alterations will be assessed through lectin‑binding assays. Characterizing these changes may also be valuable for the development and refinement of new biomarkers.
Our overarching hypothesis is that the imbalance of all these proteins converges on the apoE pathway, driving disease progression beyond the presence of a specific polymorphism or allelic variant (apoE4) as a risk factor.