Alzheimer's Disease Mutations Disrupt Neural Stem Cell Fate and Early Brain Development

Alzheimers disease (AD) has been largely considered as an age-related disease, mainly affecting mature or aging adult brain. Recent studies show that AD-associated mutations could impair early life, even during neurodevelopment. However, due to the complex of AD mutations and neurodevelopmental regulations, how mutations in specific genes affect the origin of neurodevelopment is still largely under studied. In this study, we investigate how AD mutations in App gene impact neurodevelopment, with a focus on NSC dynamics and the balance between neurogenesis and gliogenesis. We employed the 5xFAD transgenic line and the APPNL-G-F knock-in model, RNA sequencing, neurosphere assay and histological analyses on the cortex and hippocampus across critical developmental timepoints. Our results reveal that the APPNL-G-F model exhibits early gene expression changes, with suppressed stem cell proliferation, impaired neurogenesis, upregulation of gliogenesis and enhanced neuroinflammatory pathways. In contrast, the 5xFAD model displays minimal embryonic differences, with pronounced postnatal alterations likely driven by both gene mutations and APP overexpression. These findings indicate that AD mutations can inherently impair NSC self-renewal and differentiation, resulting in a suboptimal brain structure that have potentially higher vulnerability towards AD pathology in later life.