Protocol for the induction of human spinal motor neurons from human induced pluripotent stem cells for studying amyotrophic lateral sclerosis.

Here, we present a protocol for inducing spinal lower motor neurons (LMNs) from human induced pluripotent stem cells (iPSCs). We describe steps for preparation of a chemically induced transitional state (CTraS), transduction with Sendai virus, and LMN differentiation and maintenance. We then detail procedures for live imaging for single-cell-based survival analysis and neurite length of LMNs using BioStation and immunocytochemistry for induction efficiency check. This protocol is optimized for amyotrophic lateral sclerosis (ALS) research and large-scale screening. For complete details on the use and execution of this protocol, please refer to Setsu et al.1.