Deficiency of FABP7 Triggers Premature Neural Differentiation in Idiopathic Normocephalic Autism Organoids

Abstract Autism spectrum disorder (ASD), which is caused by heterogeneous genetic and environmental factors, is characterized by diverse clinical phenotypes linked to distinct pathological mechanisms. ASD individuals with a shared clinical phenotype might contribute to revealing the molecular mechanism underlying ASD progression. Here, it is generated induced pluripotent stem cell (iPSC)‐derived cerebral organoids from normocephalic individuals with ASD in a prospective birth cohort with a shared clinical diagnosis. Multiple cell lines and time series scRNA‐seq combined with a histomorphological analysis revealed premature neural differentiation of neural stem cells (NSCs) and decreased expression of Fatty acid binding protein 7 (FABP7) in ASD organoids. It is subsequently revealed alterations in the phosphorylation levels of Mitogen‐Activated Protein Kinase Kinase 1/2 (MEK1/2), which are downstream of FABP7, and the regulation of the FABP7/MEK pathway reversed improper neural differentiation in the ASD organoids. Moreover, both Fabp7‐knockdown and MEK2‐overexpressing mice exhibited repetitive stereotyped behaviors and social defects relevant to autism. This study reveals the role of the FABP7/MEK pathway in abnormal NSC differentiation in normocephalic individuals with ASD, which might provide a promising therapeutic target for ASD treatment.