Disease-related AUTS2 disruption causes an imbalance of neuronal/glial lineage specification through the WNT/ß-catenin pathway (RNA-Seq).
Individuals with disruptions in the Autism Susceptibility Candidate 2 (AUTS2) gene frequently exhibit symptoms like intellectual disability, microcephaly, growth retardation, and distinct skeletal and facial differences. The role of AUTS2 in neurodevelopment has been explored using animal models and in vitro embryonic stem cell models. However, the precise molecular mechanisms through which AUTS2 influences neurodevelopment, particularly in humans, are not thoroughly understood. To address this, our study employs a 3D human organoid culture system, in combination with genetic, genomic, cellular, and molecular approaches, to investigate how AUTS2 impacts neurodevelopment through cellular signaling pathways. We used CRISPR/Cas9 technology to create AUTS2-deficient human embryonic stem cells (hESCs), replicating a 190kb genetic deletion observed in a patient. These cells were then differentiated into cerebral organoids. Our single-cell RNA sequencing (scRNA-seq) analysis of these organoids indicates that the absence of AUTS2 results in a significant reduction in neuron-related cells and an increase in choroid plexus (ChP) epithelial cells. Notably, our research reveals that AUTS2 negatively regulates the Wnt/ß-catenin signaling pathway, evidenced by the observed overactivation of this pathway in AUTS2-deficient organoids as well as in a luciferase reporter cell line with AUTS2 deletion.  Importantly, treating the AUTS2-deficient cerebral organoids with a Wnt inhibitor ameliorated the abnormalities in neuronal differentiation. This study offers new insights into the role of AUTS2 in neurodevelopment and suggests new potential targeted therapies for NDDs. Overall design: To understand the role of AUTS2 in human brain development, we utilized a cerebral organoids model system with the CRISPR/Cas9-engineered hESCs with AUTS2 deletion. We then performed bulk RNA-seq on the day 75 WT, AUTS2+/- and AUTS2-/- cerebral organoids.