Fig 1: Transcriptome changes and Olig2 mRNA levels after cuprizone intoxication. Volcano plots of differentially expressed genes of 1 week cuprizone samples (a) and 3 weeks Cuprizone + Siponimod samples (b) compared to controls. Note that key oligodendrocyte transcription factors (i.e., Olig2, Olig1, Sox10) remain stably expressed. mRNA expression of Plp1, Atf3, Cnp and Olig2 after 1 week of cuprizone intoxication in the cortex (c–f) and corpus callosum (g–j), respectively. k–i A combined OLIG2 immunohistochemistry and Olig2 RNA in situ hybridization showing OLIG2+Olig2RNA+ cells in the corpus callosum of control mice (arrows) and OLIG2−Olig2RNA+ cells after 1 week of cuprizone (arrowheads). Note the apoptotic cell lacking both OLIG2 protein and Olig2 RNA (asterisk). c–j Kruskal–Wallis test followed by Dunn’s multiple comparisons test. l one-way ANOVA followed by Tukey’s multiple comparisons test. a, b n = 4; c–j Ctrl n = 6, Cup-Veh and Cup-Sipo n = 4; l both groups n = 4. Scale bar: 50 µm, insets: 20 µm, high-power insets: 10 µm