Ubiquitin staining of SOD1 human ESC-derived sMNs. (A): Immunocytochemical staining of ubiquitin (green) and HB9 (red). An abnormal staining pattern was observed in G93A SOD1-expressing sMNs. Arrowheads show rough staining of ubiquitin or HB9, which might be abnormal ubiquitin inclusions. (B): Quantitative analysis of cells with ubiquitin inclusions (green bars), HB9-positive sMNs (purple bars), and sMNs with ubiquitin inclusions (yellow bars). Mean ± SEM; n = 9; Steel-Dwass test; ∗∗, p < .01. Abbreviations: sMN, spinal motor neuron; SOD, superoxide dismutase; Ub, ubiquitin; WT, wild-type.