Fig. 2: Conditional genetic ablation of OPC-expressed Sulf1/2 accelerates oligodendrocyte recruitment and lesion colonization following demyelination.

a–j Dual RNAscope in situ hybridization (ISH) of mouse spinal cord (a–e) revealed increased Sulf1 and Sulf2 mRNA expression following lysolecithin-induced demyelination (f–j; 5 d.p.l.). Sulf1 (gray), Sulf2 (green), or Pdgfra mRNA (red) and DAPI (blue). Yellow arrows denote Pdgfra⁺ OPCs that co-expresses Sulf1/2. Blue arrows denote Sulf2⁺Pdgfra⁺ OPCs or Sulf1⁺Pdgfra⁺ OPCs. RNAscope images were imaged by confocal microscopy, others using widefield epifluorescence. Inducible NG2creER-mediated OPC-specific ablation of Sulf1/2 (Sulf1/2 cKO) in adult mice followed by lysolecithin-induced demyelination (k–r). Analysis of OPC dynamics at 5 days post lesion (d.p.l.) (o–p) (n = 6 and 3 mice, for WT and Sulf1/2 cKO respectively) and 7 d.p.l. (q–r) (n = 5 and 6 mice, for WT and Sulf1/2 cKO, respectively). At 5 d.p.l., Olig2⁺ cell density was significantly increased in Sulf1/2 cKO (o) (**p = 0.0016, two-sided t test). No difference in the proportion of proliferating EdU⁺Olig2⁺ cells compared to wild type (p). At 7 d.p.l., Sulf1/2 cKO exhibited increased overall Olig2⁺ and postmitotic Olig2⁺CC1⁺ oligodendrocyte density (m, n) (cells/mm² quantified in q, **p = 0.0027 and 0.00071, two-sided t test). The percentage of CC1⁺Olig2⁺ oligodendrocytes among Olig2⁺ cells was increased in Sulf1/2 cKO animals compared to controls (r, ***p = 0.0009, two-sided t test). Mean ± SEM shown. Scale: 20 µm (a, f, c, h), 40 µm (b, g, d–j), and 10 µm (k–n).