Swift Induction of Human Spinal Lower Motor Neurons and Robust ALS Cell Screening via Single-Cell Imaging

This study presents a newly developed method to rapidly and efficiently induce human spinal lower motor neurons (LMNs) from induced pluripotent stem cells (iPSCs) for elucidation of pathomechanism or drug screening in amyotrophic lateral sclerosis (ALS). Previous methods had several limitations, such as poor efficiency and low purity of LMN induction and the labor-intensiveness of the induction and evaluation procedures. Our new protocol achieved nearly 80% induction efficiency in just a few weeks by combining a small molecule-based approach and transduction of transcription factors. To overcome cellular heterogeneity, we analyzed morphology and viability of iPSC-derived LMNs on a cell-by-cell basis using time-lapse microscopy and machine learning, establishing a highly accurate pathophysiological evaluation system. Our rapid, efficient, and simplified protocol and our single-cell based evaluation method provides a way to conduct large-scale analysis and drug screening using motor neurons derived from iPSCs.