Cell‐autonomous role of the AD susceptibility gene BIN1 in the regulation of hiPSC‐derived neurons network activity

Abstract Background Alzheimer’s disease (AD) is a multifactorial disease with a strong genetic background. Recent genomic wide association studies have identified several loci linked to an increased risk of AD. However, genes regulated by these variants and the pathophysiological mechanisms regulated by those genes remain largely elusive. In this work, we studied the role of Bridging Integrator 1 (BIN1), the second most important AD risk gene after APOE, in neurons generated from human induced pluripotent stem cells (hiPSCs) in bi‐dimensional cultures and cerebral organoids. Method We generated isogenic BIN1 wild‐type (WT), heterozygous (HET) and knockout (KO) hiPSC lines and used these cells to generate human‐induced neurons (hiNs) in bi‐dimensional (2D) and three‐dimensional (cerebral organoids) cell cultures. Next, we used calcium imaging and multi‐electrode array electrophysiology to study the functional properties of hiNs networks. Single‐nucleus RNA‐sequencing (snRNAseq) was used to identify gene expression alterations in individual cell types/subtypes. APP processing and TAU phosphorylation was assessed by western blotting and Alphalisa. Result We observed that deletion of BIN1 is sufficient to cause neuronal hyperactivation and network desynchronization in a cell‐autonomous fashion. These functional changes are observed both in 2D cultures and cerebral organoids, and are correlated with increased Tau phosphorylation and transcriptional changes similar to those observed in the brains of AD patients, particularly in glutamatergic neurons. Conclusion Our results reveal a role for BIN1 in the regulation of electrical activity in human neurons and suggest that its implication in AD pathogenesis could be related to the neuronal and network dysfunctions observed in the AD brain.