GDF15 and HB-EGF protect SOD1G93A motoneurons from NO-induced death. the number of independent experiments (each performed in triplicate or quadruplicate) is indicated in brackets. (A) Wildtype motoneurons were cultured for 24 h in the presence of NTFs and incubated with the NO donor DETANONOate (20 µM) in combination with GDF15 (10 ng/mL) and HB-EGF (20 ng/mL). The percentage of surviving motoneurons was determined 48 h later. (B) SOD1G93A-expressing motoneurons were maintained in culture for 24 h and treated (or not) with DETANONOate (20 µM), GDF15 (10 ng/mL), or HB-EGF (20 ng/mL) for 48 h. The number of surviving motoneurons is expressed as a percentage of the number of motoneurons in the control condition (in the presence of NTFs only). Histograms show mean values ± SEM; the number of independent experiments (each performed in triplicate or quadruplicate) is indicated in brackets. One-way ANOVA followed by Tukey’s post hoc test, * p < 0.05, ** p < 0.01, *** p < 0.001.