Advances in neural organoids: structural organization, disease modeling, and applications in gene therapy

Neural organoids and assembloids have emerged as advanced in vitro models that reproduce the cytoarchitecture and functional complexity of the human brain. This review focuses on recent applications of these three-dimensional systems for modeling neurodegenerative diseases and assessing the efficacy of gene therapy, particularly using adeno-associated viral vectors. The development of induced pluripotent stem cell technology enables the creation of patient-specific organoids that reflect individual genetic backgrounds and disease phenotypes. Neural organoids have been used to model Alzheimer's, Parkinson's, and Huntington's diseases, reproducing hallmark features such as protein aggregation, neuroinflammation, and synaptic dysfunction. They have also served as test systems for evaluating AAV-mediated gene delivery, revealing serotype-specific tropism and supporting optimization of vector design and gene expression. Further advances include integration of immune and vascular components and the construction of multi-regional assembloids that replicate inter-regional neuronal communication and complex network dynamics. Ongoing standardization and scalability of neural organoid systems, combined with bioengineering and analytical innovations, are expected to enhance reproducibility and translational relevance. The convergence of organoid models with gene therapy testing frameworks may accelerate preclinical validation and contribute to the development of precision approaches in neurology.