Nuclear export inhibitor KPT-350 transiently ameliorates motor deficits, motor neuron loss in GLAST+/−/GLT1-cKO mice. A, KPNB1 immunofluorescence of motor neurons in the lumbar ventral horn from control and GLAST+/−/GLT1-cKO mice at 7 weeks of age. Sections were triple labeled with anti-KPNB1 (green), DAPI (blue), and anti-ChAT (white). Scale bar, 10 μm. B, RanBP-1 immunofluorescence of motor neurons in the lumbar ventral horn from control and GLAST+/−/GLT1-cKO mice at 7 weeks of age. Sections were triple labeled with anti-RanBP-1 (green), DAPI (blue), and anti-ChAT (white). Scale bar, 10 μm. C, CAS immunofluorescence of motor neurons in the lumbar ventral horn from control and GLAST+/−/GLT1-cKO mice at 7 weeks of age. Sections were triple labeled with anti-CAS (red), DAPI (blue), and anti-ChAT (white). Arrowheads indicate the reduction or absence of nuclear CAS immunoreactivity in GLAST+/−/GLT1-cKO mice. Scale bar, 10 μm. D, KPT-350 treatment delayed motor deficits in the hanging wire test (n = 10 for vehicle-treated and n = 9 for KPT-350-treated GLAST+/−/GLT1-cKO mice). *p < 0.05 (post hoc unpaired two-tailed t test at corresponding time point after two-way repeated-measures ANOVA). E, Amelioration of hindlimb paralysis in GLAST+/−/GLT1-cKO mice after KPT-350 treatment. Arrow indicates the fully paralyzed hindlimb of the vehicle-treated GLAST+/−/GLT1-cKO mice. Arrowhead indicates the hindlimb upon which the KPT-350-treated GLAST+/−/GLT1-cKO mice could stand. F, ChAT immunofluorescence of the lumbar ventral horn from vehicle-treated and KPT-350-treated GLAST+/−/GLT1-cKO mice at 7 weeks of age. Scale bar, 100 μm. G, Quantification of ChAT-positive motor neurons at 7 weeks of age (n = 7 for vehicle-treated and n = 5 for KPT-350-treated GLAST+/−/GLT1-cKO mice). ***p < 0.001 (unpaired two-tailed t test). H, Nup153 immunofluorescence of lumbar ventral horns from vehicle-treated and KPT-350-treated GLAST+/−/GLT1-cKO mice at 7 weeks of age. Sections were triple labeled with anti-Nup153 (magenta), DAPI (blue), and Neurotrace (fluorescent Nissl stain, white). Rectangles in the middle panel are enlarged in the right panel. Scale bars: left, 20 μm; right, 5 μm. (I) Quantitative analysis of Nup153-immunostained sections. The percentage of Nup153-negative large ventral horn neurons is not changed in GLAST+/−/GLT1-cKO mice treated with KPT-350 (n = 3 for each groups). n.s., Not significant (unpaired two-tailed t test). All data are expressed as the mean ± SEM.