Fig 1: PIWI proteins were dysregulated in postmortem sALS samples. A RT-qPCR for PIWIL1, PIWIL2, PIWIL3, PIWIL4 expression of mRNA using the ?CT method. RT-qPCR using the ?CT method for PIWIL1 and PIWIL4 showed significant differences between ALS and control samples, while PIWIL2 and PIWIL3 showed non-significant differences. B RT-qPCR results of postmortem PIWIL1 and PIWIL4 expression using a control pool for the standard curve method. One-tailed t-test and the Wilcoxon test were used for statistical calculations. PIWIL1 was upregulated 1.2–1.9-fold in sALS patients compared to the mean of control samples, by the standard curve method. C Western blot analysis of PIWIL1 and PIWIL4 in postmortem samples. The increase of PIWIL1 protein and the decrease of PIWIL4 protein were confirmed in ALS samples. D Quantitative analysis of PIWIL1 and PIWIL4 in a Western blot normalized to GAPDH. The increase of PIWIL1 protein and the decrease of PIWIL4 protein were statistically confirmed. ns: not significant. *p < 0.05, **p < 0.01