Brain Organoids in Neurodegenerative Disease Modeling: Advances, Applications and Future Perspectives.

Neurodegenerative diseases (NDDs) represent incurable and debilitating conditions characterized by progressive deterioration of neurological function. Investigating neurodegeneration remains a critical global challenge in aging societies. Brain organoids-self-organizing three-dimensional structures derived from human pluripotent stem cells-recapitulate cell types and cytoarchitectures of the developing human brain. This in vitro model system has advanced our bridge between conventional two-dimensional cultures and in vivo models. Brain organoids emulate early neural tube formation, neuroepithelial differentiation, and whole-brain regionalization. Furthermore, region-specific organoid models now facilitate mechanistic investigation into acquired and inherited NDDs' pathogenesis, alongside drug discovery and toxicity screening. In this review, we (i) delineate the epidemiology and pathobiology of major NDDs, (ii) analyze limitations of current animal models, (iii) critically evaluate brain organoid generation methodologies, and (iv) focus on organoid applications in modeling Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS).