LINKING AXONAL PATHOLOGY TO ELN DYSFUNCTION VIA POLYGENIC RISK IN HUMAN TISSUE AND HIPSC MODELS OF ALZHEIMER’S DISEASE

Axonal organization in the human brain remains incompletely characterized, particularly in the context of neurodegenerative diseases such as Alzheimer’s disease (AD). This represents a critical gap, as emerging evidence suggests that axonal abnormalities (particularly the emergence of dystrophic axons) occur early in AD and may be linked to disruptions in the endo-lysosomal network (ELN). However, the mechanistic relationship between ELN dysfunction and axonal pathology remains poorly understood.

Genetic studies have implicated ELN-related genes in AD risk, motivating the development of an endo-lysosomal polygenic risk score (ePRS) that aggregates GWAS-identified SNPs weighted by effect size, allele frequency, and dosage to quantify cumulative genetic burden.

This project integrates postmortem brain tissue from an ePRS-stratified donor cohort with donor-matched human induced pluripotent stem cell (hiPSC)-derived neuron models to examine how genetic risk influences axonal structure and ELN function.

We apply a hydrogel-based expansion and clearing pipeline optimized for large-scale postmortem tissue, enabling high-throughput, single-axon resolution imaging via light-sheet microscopy. This pipeline reliably resolves region-specific patterns of axonal organization in human white matter, confirming the feasibility of high-resolution axonal mapping. By applying these methods to brain regions that span the stages of AD progression, we aim to identify disease-associated changes in axonal architecture. In parallel, we use donor-matched hiPSC-derived neurons cultured in microfluidic chambers to isolate axons from somas and perform live-cell imaging of ELN dynamics using LysoTracker. This dual-platform framework aims to elucidate how polygenic risk for ELN dysfunction contributes to axonal pathology in Alzheimer’s disease.