Cell Inspire Bio Shenzhen, Guangdong, China (People's Republic)
Abstract: Alzheimer’s disease (AD) is a complex neurodegenerative disease. However, lacking suitable cellular models for drug candidate screening and validation, and lacking enough diversity in existing compound libraries, hindered the development of AD drug discovery. To overcome those hurdles, we generated a series of iPSC-based AD disease models using the cutting-edge genome editing technology mediated by CRISPR/Cas9. We selected an iPSC line with BACE1 overexpression (BACE1 iPSC) for further characterization and drug screening. We differentiated BACE1 iPSCs into neuronal cells and tested the secreted A𝛃40 and A𝛃42 levels in the culture supernatant. In addition, we manufactured neural progenitor cells (NPCs) derived from these genetically modified iPSCs in a large scale, and then further differentiated them into AD-relevant neuronal cells for high throughput drug screening. Our results showed that, BACE1 iPSC retain pluripotency and normal karyotype after genetic modifications. The expression levels of BACE1 were around 80-100 folds higher in BACE1 iPSCs and their derived neural progenitor cells and neurons compared to their relative control. The expression level of BACE1 encoded protein, β-secretase 1, is around 300-600 ng/mg total protein of BACE iPSC derived NSC and generic neurons, which is significantly higher than their control counterpart. And the ectopic expression level of β-secretase 1was stable during neuronal induction from NSCs. Interestingly, the Aβ42 and Aβ40 level were increased significantly in NSCs, or neurons derived from BACE1 iPSCs compared to control cells. Furthermore, we established a workflow for generating NPCs and generic neurons from BACE1 iPSC, and these cells can be used to screen Aβ42 lowering drugs in vitro. With this in vitro platform, we conducted a high-throughput screening of natural chemical compounds and herb extracts derived from traditional Chinese medicines (TCM) and get 6 out of around 100 TCM that can significantly downregulate Aβ42 level. We further confirmed that 2 of these 6 compounds can reduce Phospho-Tau level in BACE1 iPSC-derived generic neurons. Our results indicate that our AD model offers a golden opportunity for development of novel therapeutics for treatment of AD.
