ALZHEIMER’S DISEASE MODELS IN IPSC-DERIVED GLUTAMATERGIC NEURONS SHOW INCREASED SECRETION OF PATHOGENIC AMYLOID BETA PEPTIDES

Alzheimer’s disease (AD), a complex, multifactorial neurodegenerative disease, is challenging to study in vitro due to a lack of physiologically relevant models. ioGlutamatergic Neurons are deterministically programmed human iPSC-derived excitatory neurons that provide a consistent, scalable model to study such diseases. A panel of AD models in ioGlutamatergic Neurons was developed and characterised to determine the effects of mutations in PSEN1 and APP on amyloid beta (A-beta) production.

CRISPR-Cas9 was used to engineer mutations in PSEN1 and APP in the parental iPSC-line of the ioGlutamatergic Neurons, which were subsequently programmed using opti-ox technology to generate the disease model cells. The disease models were cultured alongside their genetically matched control. Supernatant was collected on days 10, 20 and 30, and concentrations of A-beta38, A-beta40 and A-beta42 were determined by ELISA.

ioGlutamatergic Neurons carrying the PSEN1 M146L and APP V717I mutations secreted significantly more A-beta42 compared to their wild-type control, showing higher A-beta42:40 ratios. Importantly, a clear correlation between genotype and A-beta42:40 ratios was observed, as wild type, heterozygous and homozygous mutants showed a stepwise increase in A-beta42 production relative to A-beta40. ioGlutamatergic Neurons APP KM670/671NL secreted significantly more A-beta38, A-beta40, and A-beta42 than their wild type control, and the A-beta42:40 ratio did not increase, as expected.

ioGlutamatergic Neurons with mutations in PSEN1 or APP recapitulate the increase in A-beta42 secretion observed in Alzheimer’s patients. This demonstrates their validity as an in vitro model to study AD and for the discovery of drugs targeting the pathogenic A-beta pathway.