Fig. 7: Regeneration in human utricles.

a An elongated hair cell precursor cell (HCPC, arrowhead) expressing a low level of GPX2 (magenta), MYO7A (blue), and DAPI (gray). Dashed line marks the basement membrane (BM). Magnified image showing a GPX2/MYO7A⁺cell, whose nucleus is lower than other HCs. b, c Five patterns of dynamic expression of transcription factors along the type I and II hair cell lineages: some upregulated, some downregulated, and others transiently expressed in both type I and II lineages. (b: 1, 3 = up, 2, 5 = down, 4 = transient, c: 1, 3 = transient, 2-down/transient, 4, 5 = up) (validated markers highlighted in red. Also see the Source Data file). The location of cells along pseudotime for each lineage is depicted as cell density below the heatmaps. d shows elongated HCPCs (arrowhead) expressing GPX2 (magenta), ATOH1 (yellow), MYO7A (blue), and DAPI (gray) with a nucleus close to the BM. e Nuclei of HCPCs are significantly closer to the BM that those of HCs and supporting cells. f Dynamic expression and SWNE plots predicting upregulation of both POU4F3 and GFI1 as supporting cells transition to both type I and II HCs, with HCPCs colored in magenta. g–h” VS tissues contained many more POU4F3⁺/SOX2⁺/MYO7A⁻ (red/blue/green) HCPCs (arrowheads) than OD tissues. Orthogonal views show POU4F3⁺/SOX2⁺/MYO7A⁻ cells (arrowhead) with nuclei near the BM. Occasional elongated POU4F3⁺/SOX2⁺/MYO7A⁻ cells (asterisks) were found in VS utricle (h”), with nuclei near the BM and below that of other HCs. i The percentage of POU4F3⁺/MYO7A⁻ supporting cells was significantly higher in VS than OD tissues. j Percentages of GFI1⁺/MYO7A⁻ supporting cells are significantly higher in VS compared to OD tissues. Data shown as mean ± S.D. and compared using two-way Student’s t-tests or compared using Kruskal–Wallis with Dunn’s multiple comparisons. **p = 0.0016 between HCs and HCPCs, ***p < 0.0001 between HCs and SCs in (e), **p = 0.0091 in (i), *p = 0.0384 in (j). n = 19 HCs, 69 SCs, and 7 HCPCs from 3 VS tissues in (e). n = 12 for VS, 3 for OD tissues in (i), n = 9 for VS, 2 for OD tissues in (j). Scale bar = 25 and 5 µm in (a, d), 20 µm in (g–h”). Source data are provided as a Source Data file.