Figure 9. TSCs remain intact and associated with hair follicles following dorsal cutaneous nerve axotomy and distal axon degeneration.

(A and A′) Whole-mount immunostaining of S100 (red) and NFH (green) shows that 17 days after dorsal cutaneous nerve axotomy, while NFH⁺ cutaneous nerve have completely degenerated in the denervated skin (A′, right back skin) compared to the control skin (A, left back skin), TSCs remain intact and associated with hair follicles (A′). (B and B′) Enlarged views of boxed regions in A and A′. At control hair follicles (B), TSCs are associated with longitudinal lanceolate endings and circumferential endings (arrow). At denervated hair follicles (B′), TSCs that were associated with longitudinal lanceolate endings prior to denervation appear normal, while TSCs associated with circumferential axonal terminals (arrows) are partially lost (arrow). (C and C′) Whole-mount immunostaining of S100 (red) and NFH (green) shows that, 44 days after axotomy, TSCs in the denervated skin (C′) remain intact. (D and D′) Enlarged views of boxed regions in C and C′ show that compared to TSCs in the control skin (D), TSCs that were associated with longitudinal lanceolate endings at denervated hair follicles (D′) appear normal, while TSCs associated with circumferential axonal terminals are completely lost (arrow in D). (E and E′) Whole-mount immunostaining of S100 (red) and MBP (green) shows that, at 44 days after axotomy, while myelinating Schwann cells have completely degenerated, TSCs in the denervated skin remain intact (E′). (F and F′) In Plp1^CreER;Rosa26^GCamp3 animals, TSCs were induced to express GCaMP3 by tamoxifen injection before dorsal cutaneous nerve axotomy. Immunostaining for GFP (green) and Tuj1 (red) shows that, at 14 days following axotomy, while Tuj1⁺ cuanteous axons have completely degenerated, genetically labeled TSCs remain intact (F′). (G) Quantification of TSC numbers 5 weeks after denervation surgery shows no changes in TSC numbers at both guard hair and non-guard hair follicles in denervated skin compared to those at the control skin. n = 3. Animals around 8 weeks of age were used for all whole-mount immunostaining experiments in A–E′ and G. Plp1^CreER;Rosa26^GCamp3 mice around 4 weeks old were used in experiments shown in F and F′. Scale bars, 50 μm.

DOI: http://dx.doi.org/10.7554/eLife.01901.015

Figure 9—figure supplement 1. Genetically labeled immature Schwann cells after skin denervation.

Plp1^CreER;Rosa26^LSL-YFP mice were treated with tamoxifen before receiving skin denervation surgeries and examined 4 weeks after denervation. (A–D) On the sham-operated control side of the back skin, wholemount immunostaining with GFP (A), MBP (B) and S100 (C) show that genetically-labeled, YFP⁺ myelinating Schwann cells are positive for MBP and S100 (Arrows in A–D). (A′–D′) Same staining was performed on the denervated back skin. Genetically labeled, YFP⁺ TSCs remained at hair follicles after denervation. GFP⁺ sheaths that are negative for S100 and MBP can be observed (arrows in A′–D′) and they are likely to be genetically labeled immature Schwann cells. Animals around 8 weeks old were used in these experiments. Scale bar, 50 μm.

DOI: http://dx.doi.org/10.7554/eLife.01901.016