Fig. 4: The mature taste receptor expressing K8 dedifferentiates into progenitor-like cells expressing K14 after GLx.
From: Epithelial plasticity enhances regeneration of committed taste receptor cells following nerve injury
a Schematic of the experimental procedure for lineage tracing of K8-positive taste receptor cells. b Schematic of lineage labeling of the taste receptor cells and dedifferentiation after GLx. Tamoxifen-induced Cre activates tdTomato fluorescent protein (red), which labels K8 cells and their progeny in taste buds. c–c'' A subset of taste receptor cells in the sham surgery mice expressed the tdTomato signal. d–d'' Two subtypes of remaining taste receptors are observed at 2 weeks after GLx, the remaining taste receptor cells (arrowhead) expressing tdTomato and newly formed taste receptor cells (arrow) derived from stem/progenitor cells during the chase period. d' The remaining taste receptor cells express Trpm5 and (d'') Snap25, thus indicating the presence of Type II and Type III taste receptor cells. e‒e'' At 4 weeks after GLx, K8-derived taste receptor cells are observed in the taste bud (arrowhead) and nontaste epithelial cells (arrow). e' Trpm5-expressing (Type II) and (e'') Snap25-expressing (Type III) taste receptor cells are derived from the remaining K8-positive cells (arrowhead). f At 6 weeks after GLx, the regenerated taste receptor cells exhibit the presence of K8 (arrowhead). f' A subset of Trpm5-expressing (Type II) and (f'') Snap25-expressing (Type III) taste receptor cells are K8-positive at 6 weeks after GLx. g Quantification of surviving taste receptor cells at 2 weeks after GLx reveals that K8-positive, tdTomato-negative cells are more abundant than K8-positive and tdTomato-negative cells. h, i Quantification of the surviving taste receptor cells at 4 and 6 weeks after GLx reveals that the number of K8- and tdTomato-negative cells is increased compared to the number at 2 weeks after GLx; however, the number of K8 cells derived from K8–positive differentiated cells is similar at 4 and 6 weeks after GLx. j K8-derived tdTomato-positive cells localized within the taste buds in the sham mice. k–m Three weeks after GLx, K8-derived cells were observed in the majority of the trench region of the CVP. The K8-derived cells express (k) the basal/progenitor cell marker K14, (l) proliferative cell marker PCNA, and (m) the taste progenitor marker Sox2. Data on the graph are displayed as the mean ± SD. Scale bar: c–f''—25 µm, j–m—100 µm.
