Fig 1.
Schematic representation of the different phases of Schwann cell development.
Schematic images of transverse sections through the trunk of E9.0 (A), E10.5 (B), E12.5 (C), E14.5 (D) and E18.5 (E) embryos, and a longitudinal section through the postnatal sciatic nerve (F). Insets in C-F show transverse sections through the sciatic nerve. bc, boundary cap; dr, dorsal root; drg, dorsal root ganglia; nt, neural tube; sn, spinal nerve; vr, ventral root.
Fig 2.
Expression of SC lineage markers in E9.0 NCCs.
(A-E,A'-D',A''-D'') Co-expression of Sox10 with Sox9 (A-A''), AP2α (B-B''), Pax3 (C-C''), Nfatc4 (D-D'') in E9.0 NCCs. A-D are merged images of Sox10 (green) and protein of interest (red). Blue is DAPI counterstain. A'-D' shows expression profiles of the protein of interest, while A''-D'' show Sox10 expression. Arrows indicate co-expression of protein of interest with Sox10 in NCCs taking the ventral migratory pathway. Quantification of percent Sox10+ co-expression with each of the proteins of interest (E). Error bars = S.E.M. nt, neural tube. Scale bars, 40μm.
Fig 3.
Expression of SC lineage markers in E10.5 NCC precursors.
(A-P) Co-expression of Sox10 with Sox9 (A-C'), AP2α (D-F'), Pax3 (G-I'), Nfatc4 (J-L'), and Etv5 (M-O') in transverse sections through the E10.5 trunk. Merged images of the protein of interest (red) with Sox10 (green) (A,D,G,J,M). Blue is DAPI counterstain. High magnification images of the DRG, showing merged images of the protein of interest (red) and Sox10 (green) (B,E,H,K,N), and single protein of interest images in white (B',E',H',K',N'). High magnification images of the ventral roots, showing merged images of the protein of interest (red) and Sox10 (green) (C,F,I,L,O), and single protein of interest images in white (C',F',I',L',O'). Arrows mark co-expression of proteins of interest with Sox10 in NCC precursors. Quantification of percentage of Sox10+ cells that co-express each of the proteins of interest (P). Error bars = S.E.M. drg, dorsal root ganglion; nt, neural tube; scg, sympathetic chain ganglion; sn, spinal nerve; vr, ventral root. Scale bars, 60μm.
Fig 4.
Expression of SC lineage markers in E12.5 SCPs.
(A-Y) Co-expression of Sox10 with Sox9 (A-D'), AP2α (E-H'), Pax3 (I-L'), Etv5 (M-P'), Sox2 (Q-T'), and Egr1 (U-X') in transverse sections through the E12.5 trunk. Low magnification merged images of protein of interest (red) and Sox10 (green) (A,E,I,M,Q,U). Blue is DAPI counterstain. High magnification images of the DRG, showing merged images of the protein of interest (red) and Sox10 (green) (B,F,J,N,R,V), and single protein of interest images in white (B',F',J',N',R',V'). High magnification images of the dorsal roots, showing merged images of the protein of interest (red) and Sox10 (green) (C,G,K,O,S,W), and single protein of interest images in white (C',G',K',O',S',W'). High magnification images of the ventral roots, showing merged images of the protein of interest (red) and Sox10 (green) (D,H,L,P,T,X), and single protein of interest images in white (D',H',L',P',T',X'). Arrows indicate co-expression of proteins of interest with Sox10 in SCPs. Quantification of percentage of Sox10+ cells that co-express each of the proteins of interest (Y). Error bars = S.E.M. dr, dorsal root; drg, dorsal root ganglion; sc, spinal cord; scg, sympathetic chain ganglion; sn, spinal nerve; vr, ventral root. Scale bars, 60μm.
Fig 5.
Expression of SC lineage markers in E14.5 iSCs.
(A-Q) Co-expression of Sox10 with Sox9 (A-D'), AP2α (E-H'), Sox2 (I-L') and Egr1 (M-P') in transverse sections through the E14.5 trunk. Low magnification merged images of protein of interest (red) and Sox10 (green) (A,E,I,M). Blue is DAPI counterstain. High magnification images of the DRG, showing merged images of the protein of interest (red) and Sox10 (green) (B,F,J,N), and single protein of interest images in white (B',F',J',N'). High magnification images of the dorsal roots, showing merged images of the protein of interest (red) and Sox10 (green) (C,G,K,O), and single protein of interest images in white (C',G',K',O'). High magnification images of the ventral roots, showing merged images of the protein of interest (red) and Sox10 (green) (D,H,L,P), and single protein of interest images in white (D',H',L',P'). Arrows indicate co-expression of proteins of interest with Sox10 in iSCs. Quantification of percentage of Sox10+ cells that co-express each of the proteins of interest (Q). Error bars = S.E.M. dr, dorsal root; drg, dorsal root ganglion; sc, spinal cord; vr, ventral root. Scale bars, 60μm.
Fig 6.
Expression of SC lineage markers in E18.5 late immature/pro-myelinating SCs.
(A-K) Co-labeling of Sox10 with Sox9 (A-B'), AP2α (C-D'), Jun (E-F') and Yy1 (I-J'), and co-labeling of Sox9 and Oct6 (G-H') in transverse sections through the E18.5 trunk. Low magnification merged images of protein of interest (red) and Sox10 (green) (A,C,E,I) or Sox9 (G). High magnification images of the DRG, showing merged images of the protein of interest (red) and Sox10 (or Sox9) in green (B,D,F,H,J), and single protein of interest images in white (B',D',F',H',J'). Blue is DAPI counterstain in A-I. Arrows indicate co-expression of proteins of interest with Sox10 (or Sox9) in late immature and pro-myelinating SCs. Quantification of percentage of Sox10+ cells that co-express each of the proteins of interest (K). Error bars = S.E.M. drg, dorsal root ganglion; sc, spinal cord; sn, spinal nerve; vr, ventral root. Scale bars, 60μm.
Fig 7.
Expression of SC lineage markers in P7 mature SCs.
(A-F'') Co-labeling of Sox10 with Sox9 (A-A''), Nfatc4 (B-B''), Jun (C-C''), Oct6 (D-D''), Yy1 (E-E''), and Egr2 (F-F'') in longitudinal sections of the P7 sciatic nerve. Merged images of the protein of interest in red and Sox10 in green (A-F). Blue is DAPI counterstain. Expression profiles of the protein of interest (A'-F') and Sox10 (A''-F''). Arrows indicate co-expression of proteins of interest with Sox10 in P7 mature SCs Quantification of percentage of Sox10+ cells that co-express each of the proteins of interest (G). Error bars = S.E.M. Scale bars, 40μm.
Fig 8.
Expression of SC lineage markers in adult P65 uninjured sciatic nerve.
(A-I'') Co-labeling of Sox10 with fluoromyelin (A-A‴), Sox9 (B-B''), Nfatc4 (C-C''), Sox2 (D-D''), Egr1 (E-E''), and Oct6 (F-F''), Jun (G-G''), Yy1 (H-H''), Egr2 (I-I'') in longitudinal sections of the uninjured P65 sciatic nerve. Merged images of protein of interest (green), Sox10 (red) and Hoechst (blue) (B-I). Yellow arrowheads indicate co-labelled cells. Scale bars, 20μm.
Fig 9.
Expression of SC lineage markers in P65 sciatic nerve after acute nerve injury.
(A-E) Co-labeling of Sox10 (red) with Sox9 (A-A''), Nfatc4 (B-B''), Egr1 (C-C''), Yy1 (D-D''), and Egr2 (E-E'') in longitudinal sections of the injured P65 sciatic nerve. Merged images of protein of interest (green), Sox10 (red) and Hoechst (blue) (A-E). Yellow arrowheads indicate co-labelled cells. Scale bars, 20μm.
Fig 10.
Developmental glial-lineage genes are up-regulated after acute nerve injury.
(A-F) Co-labeling of Sox10 (grey) with fluoromyelin (red) and GFP (green) in the distal stump of Sox2-eGFP mice after 5 dpi (A-A‴). Co-labeling of Sox10 with Sox2 (B-B''), Oct6 (C-C''), and Jun (D-D''). Merged images of protein of interest (green), Sox10 (red) and Hoechst (blue) (A-E). Yellow arrowheads indicate co-labelled cells. Quantification of percentage of Sox10+ cells that co-express each of the proteins of interest (F). Error bars = S.E.M. Scale bars, 20μm.
Fig 11.
Summary of temporal expression profiles of key transcription factors in the SC lineage.
Sox9 and Sox10 are expressed throughout SC genesis, beginning at E9.0 in migrating NCCs and persisting until P65 in myelinating and non-myelinating SCs in the sciatic nerve. AP2α, Pax3 and Etv5 are also expressed in NCCs, persisting until E12.5 in SCPs with Nfatc4 expression being restricted to NCCs. Egr1 and Sox2 expression is initiated in SCPs at E12.5, persisting until E14.5 in iSCs. At E18.5, AP2α is expressed in the DRG but is undetectable in the nerves while the expression of Jun, Oct6, and Yy1 is initiated and persists till P65. Rare Sox2+Sox10+ positive cells are also detected in the P65 nerve. Egr2 expression is not detected until P7 in myelinating SCs in the sciatic nerve. Post-injury, high upregulation in expression of Sox2, Oct6, and Jun is observed, while distinct nuclear Egr1 expression is also detected. The straight lines represent continued expression of the markers through the different stages, while the dotted lines represent declining or low expression. The asterisk indicates where expression is restricted to the DRG and is undetectable in the nerves at E18.5. Markers expressed in the nerve after an acute injury have been denoted with ‘√’. The green cells represent the developing axon, while the beige cells represent the NCCs at E9.0-E10.5 and the developing SCs at E12.5 to post-natal stages.