Transcriptomic profiling of electrophysiologically characterized human iPSC-derived motor neurons having SOD1 A4V mutation

To find the molecular basis for abnormal excitability in human iPSC-derived motor neurons with the SOD1 A4V mutation and its involvement in risk of cell loss, we conducted a patch-seq, which combines genome-wide RNA sequencing and patch-clamp recording. This experiment enables excitability and gene expression to be measured simultaneously at a single cell level such that the links between the two could be explored. MNs differentiated from SOD1 A4V/+ iPSC lines and their isogenic controls were purified by introducing a GFP reporter under the control of the Hb9 promoter and GFP flow sorting. Three weeks after differentiation on P0-1 mouse cortical glial cells, whole cell current clamp recordings were made followed by single MN isolation for single cell Smart-seq2. Smart-seq2 analysis was performed on 192 neurons in two independent batches.