Fig. 1

ERp57 improves motor performance of mutant SOD1 mice. a SOD1^G93A/ERp57^WT double transgenic mice were generated by crossing heterozygous mice of SOD1^G93A and ERp57^WT transgenic lines. The mutant SOD1 mouse line overexpresses human SOD1^G93A driven by SOD1 promoter. The ERp57^WT mouse line overexpresses wild-type human ERp57 conjugated with a FLAG tag at the C-terminus driven by Prion protein promoter. b Schematic view of the protocol for characterization of SOD1^G93A/ERp57^WT mice, which were monitored weekly through their lifespan to assess several phenotypic parameters, including body weight measurements, motor performance in wire hang test and rotarod test, and clinical score. Electrophysiological activity was evaluated as compound muscle action potential (CMAP). c mRNA levels of human SOD1 (hSOD1) and human and endogenous mouse ERp57 (h/mERp57) were measured by RT-qPCR in lumbar spinal cord. Statistical analysis was performed using one-way ANOVA with Tukey’s multiple comparison test. Mean ± S.E. is shown; n.s., p > 0.05 (n = 3–7 mice per genotype). Each data point represents one animal. d Protein levels of ERp57 and SOD1 in lumbar spinal cord. h/m: human and mouse ERp57 forms. h: human ERp57 form. SOD1 western blot shows human (transgene; upper band) and mouse (endogenous; lower band) SOD1 forms. Each lane corresponds to one animal. e Representative immunofluorescence micrographs of ventral horns of the lumbar spinal cord stained against FLAG epitope in ERp57^WT construct (pseudocolored red) and misfolded human SOD1 (clone C4F6, pseudocolored green). One ventral horn is shown. Asterisk (*) indicates motoneurons discriminated by morphological and anatomical location in the ventral horn. Arrows indicate FLAG-positive cells containing misfolded SOD1. Nuclei stained with Hoechst 33,342 (pseudocolored blue). Scale bar: 50 μm. f Mice motor performance was assessed by wire hang test. Statistical analysis was performed using two-way ANOVA with Tukey’s multiple comparison test. Mean ± S.E. is shown; p values for comparison between SOD1^G93A and SOD1^G93A/ERp57^WT are shown: *, p ≤ 0.05 (n = 6–14 male mice per genotype). g Percentage of mice shown in e able to hold themselves on the wire hang test for more than 10 s at symptomatic stage (17 weeks of age). h Survival of double transgenic mice compared to SOD1^G93A transgenic group. Non-transgenic (Non-Tg) littermates were plotted as control (n = 6 male mice per genotype)