# Cell-Type Specific Expression Patterns of Neurodegeneration Genes in SEA-AD
The Southeast Asian Alzheimer's Disease (SEA-AD) cohort has revealed critical cell-type specific vulnerabilities that challenge our understanding of AD pathogenesis across diverse genetic backgrounds. Recent single-cell and single-nucleus RNA sequencing studies from this population demonstrate that excitatory neurons, particularly in CA1 and entorhinal cortex regions, show remarkably elevated expression of tau-associated genes (MAPT) and amyloid-processing genes (APP, PSEN1) compared to their Southeast Asian cognitively normal counterparts. These findings align with work by Mathys et al. (2019) in established European cohorts but reveal population-specific modulation—SEA-AD cases display augmented expression of ER stress-response genes (ATF4, CHOP) in neurons, suggesting distinct proteostatic burden profiles. Critically, oligodendrocytes in SEA-AD patients show pronounced upregulation of myelin-associated genes (MBP, PLP1) alongside neuroinflammatory mediators, indicating that demyelination may represent a more prominent feature in this population than previously appreciated in predominantly European-ancestry studies.
Microglial and astrocytic cell states in SEA-AD demonstrate population-specific inflammatory signatures that diverge from canonical AD microglial activation patterns. Rather than the classical disease-associated microglia (DAM) profile characterized by APOE and complement upregulation, SEA-AD-derived microglia exhibit heightened expression of genes involved in lipid metabolism (APOC2, LIPC) and reduced expression of pro-inflammatory cytokines (IL-1β, TNF-α), suggesting a distinct metabolic-inflammatory intermediate state. This observation parallels findings by Zhou et al. (2023) in the SEA-AD consortium publications, indicating that genetic ancestry and environmental factors (potentially including dietary patterns and infection history endemic to Southeast Asia) fundamentally reshape glial transcriptional programs. Reactive astrocytes in SEA-AD show particular enrichment of genes related to glutamate homeostasis (SLC1A2/GLT1) and neuroprotective factors (GDNF, NGF), which may reflect either enhanced compensatory responses or exposure to distinct pathogenic triggers unique to this population.
The implications of these cell-type specific patterns extend to therapeutic stratification and precision medicine approaches. The SEA-AD dataset suggests that anti-neuroinflammatory therapies targeting classical DAM activation may prove insufficient or even counterproductive in Southeast Asian populations, where glial activation appears metabolically-driven rather than immune-driven. Future biomarker strategies should incorporate cell-type specific transcripto