Whole Cell Patch Clamp Electrophysiology in Human Neuronal Cells

Whole cell patch clamp recording techniques are commonly used to assay membrane excitability, ion channel function, and synaptic activity in neurons. However, assaying these functional properties of human neurons remains difficult because of the difficulty in obtaining human neuronal cells. Recent advents in stem cell biology, especially the development of the induced pluripotent stem cells, made it possible to generate human neuronal cells in both 2-dimensional (2D) monolayer cultures and 3D brain-organoid cultures. Here, we describe the whole cell patch clamp methods of recording neuronal physiology from human neuronal cells.

The Alzheimer susceptibility gene BIN1 induces isoform-dependent neurotoxicity through early endosome defects

The Bridging Integrator 1 (BIN1) gene is a major susceptibility gene for Alzheimer’s disease (AD). Deciphering its pathophysiological role is challenging due to its numerous isoforms. Here we observed in Drosophila that human BIN1 isoform1 (BIN1iso1) overexpression, contrary to human BIN1 isoform8 (BIN1iso8) and human BIN1 isoform9 (BIN1iso9), induced an accumulation of endosomal vesicles and neurodegeneration. Systematic search for endosome regulators able to prevent BIN1iso1-induced neurodegeneration indicated that a defect at the early endosome level is responsible for the neurodegeneration. In human induced neurons (hiNs) and cerebral organoids, BIN1 knock-out resulted in the narrowing of early endosomes. This phenotype was rescued by BIN1iso1 but not BIN1iso9 expression. Finally, BIN1iso1 overexpression also led to an increase in the size of early endosomes and neurodegeneration in hiNs. Altogether, our data demonstrate that the AD susceptibility gene BIN1, and especially BIN1iso1, contributes to early-endosome size deregulation, which is an early pathophysiological hallmark of AD pathology.