Optimized Protocol to Generate Spinal Motor Neuron Cells from Induced Pluripotent Stem Cells from Charcot Marie Tooth Patients

Modelling rare neurogenetic diseases to develop new therapeutic strategies is highly challenging. The use of human-induced pluripotent stem cells (hiPSCs) is a powerful approach to obtain specialized cells from patients. For hereditary peripheral neuropathies, such as Charcot-Marie-Tooth disease (CMT) Type II, spinal motor neurons (MNs) are impaired but are very difficult to study. Although several protocols are available to differentiate hiPSCs into neurons, their efficiency is still poor for CMT patients. Thus, our goal was to develop a robust, easy, and reproducible protocol to obtain MNs from CMT patient hiPSCs. The presented protocol generates MNs within 20 days, with a success rate of 80%, using specifically chosen molecules, such as Sonic Hedgehog or retinoic acid. The timing and concentrations of the factors used to induce differentiation are crucial and are given hereby. We then assessed the MNs by optic microscopy, immunocytochemistry (Islet1/2, HB9, Tuj1, and PGP9.5), and electrophysiological recordings. This method of generating MNs from CMT patients in vitro shows promise for the further development of assays to understand the pathological mechanisms of CMT and for drug screening.