CRISPR/Cas9-Correctable mutation-related molecular and physiological phenotypes in iPSC-derived Alzheimer's PSEN2N141I neurons

Basal forebrain cholinergic neurons (BFCNs) are believed to be one of the first cell types to be affected in all forms of AD, and their dysfunction is clinically correlated with impaired short- term memory formation and retrieval. We present an optimized in vitro protocol to generate human BFCNs from iPSCs, using cell lines from presenilin 2 (PSEN2) mutation carriers and controls. As expected, cell lines harboring the PSEN2(N141I) mutation displayed an increase in the A beta 42/40 in iPSC-derived BFCNs. Neurons derived from PSEN2(N141I) lines generated fewer maximum number of spikes in response to a square depolarizing current injection. The height of the first action potential at rheobase current injection was also significantly decreased in PSEN2(N141I) BFCNs. CRISPR/Cas9 correction of the PSEN2 point mutation abolished the electrophysiological deficit, restoring both the maximal number of spikes and spike height to the levels recorded in controls. Increased A beta 42/40 was also normalized following CRISPR/Casmediated correction of the PSEN2(N141I) mutation. The genome editing data confirms the robust consistency of mutation-related changes in A beta 42/40 ratio while also showing a PSEN2-mutation-related alteration in electrophysiology.