Fig. 2: SOX2⁺ cells are present in the adrenal medulla and are derived from Schwann Cell Precursors.

A Immunohistochemistry with antibodies against SOX2 (brown) at P15 and P365 in wild type adrenal medullae. Nuclei counterstained with Hematoxylin, scale bar 20 μm. B Quantification of SOX2⁺ cells over the total nuclei of adrenal medulla. n = 3 females, 3 males for each timepoint, except for 365-day lineage tracing n = 2 females, 2 males, 3 technical replicates for each timepoint, plotted mean and SEM. One-way ANOVA multiple comparisons test: P15 vs. P17 (P-value 0.0008); P15 vs. P21 (P-value 0.9925); P15 vs. P28 (P-value 0.0386); P15 vs. P42 (P-value 0.0006); P15 vs. P84 (P-value 0.0003); P15 vs. P178 (P-value 0.0006); P15 vs. P365 (P-value 0.0013). Source data are provided as a Source Data file. C Immunofluorescence staining of P15 Sox2^eGFP/+ adrenal medulla using antibodies against SOX10 (magenta) or S100β (magenta) and GFP (green), shows double-positive cells in both (arrowheads). Immunofluorescence staining of a P15 wild type (WT) sample using antibodies against GFAP (magenta) and SOX2 (green) shows double-positive cells (arrowheads). Nuclei counterstained with Hoechst, scale bars 10 μm. n = 2 females, 2 males, 3 technical replicates. D RNAscope mRNA in situ hybridisation on wild type P15 samples shows double-positive cells for S100b (red) and Sox2 (blue), Gfap (red) and Sox2 (blue), Sox10 (red) and Sox2 (blue), Plp1 (red) and Sox2 (blue) respectively - (black arrowheads) or single positive (white arrowheads); all nuclei counterstained with Hematoxylin, scale bar 10 μm. n = 2 females, 2 males, 2 technical replicates. E UMAP of the neural crest and SCP lineages between 9.5dpc and 12.5dpc from ref. ²⁸: BCC, boundary cap cells; ChC, chromaffin cells; enteric neu., enteric neurons; SC, Schwann cells; sat. glia, satellite glia; sens. neu., sensory neurons; symp. neu., sympathetic neurons, endo. fib., endoneurial fibroblasts; tSC, terminal Schwann cells; mSC, myelinating Schwann cells; nmSC, non-myelinating Schwann cells. Trajectory of chromaffin cell (ChC) transitioning from the Hub cells (range from blue (uncommitted hub cell) to yellow (chromaffin cell)). Featureplots showing expression of Sox10, Sox2, Chga (scale Log-normalised expression with k-nearest neighbour (kNN) smoothing, ranging from blue (low expression) to red (high expression)). Graph of single features for Sox10 (blue), Sox2 (orange) and Chga (green) along pseudotime. Sox10 expression precedes that of Sox2 in this trajectory, which is maintained until expression of Chga marking chromaffin cells. F Immunofluorescence on P15 mouse adrenals from Wnt1^Cre/+;R26^mTmG/+ genotypes. Immunostaining with antibodies against SOX2 (magenta) and GFP (green) shows double-positive cells (arrowheads). Nuclei are counterstained with Hoechst, scale bars 10μm. n = 1 male, 1 female, 2 technical replicates. G Immunofluorescence on P15 mouse adrenals from a Sox10^CreERT2/+;R26^mTmG/+ line induced with tamoxifen (TMX) at 11.5dpc – immunostaining with antibodies against SOX2 (magenta) and GFP (green) shows double-positive cells (arrowheads). Nuclei counterstained with Hoechst, scale bars 10 μm.