Keratin 18 is associated with a subset of older taste cells in the rat

Zhang, Chunxiao; Cotter, Murray A.; Lawton, Anne; Oakley, Bruce; Wong, Lianna; Zeng, Qun

doi:10.1046/j.1432-0436.1995.5930155.x

Cited by 50 publications

(41 citation statements)

References 29 publications

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“…Most recently, Okubo [52] have shown that cells within taste buds arise from K14-expressing basal keratinocytes, which sit along the basement membrane of the lingual epithelium, including that of taste papillae. Taste cells within buds do not express K14, but rather express cytokeratin 8 [52,64,65]. In our studies, while BMP4-ß-gal perigemmal cells are located in a position consistent with that of proposed progenitors and many of BMP4 cells were also K14 positive, we could find no evidence that these cells are actively dividing, via both BrdU birthdating and immunostaining for known markers of proliferation.…”

Section: Discussioncontrasting

confidence: 54%

Differential expression of a BMP4 reporter allele in anterior fungiform versus posterior circumvallate taste buds of mice

Nguyen

Barlow

2010

BMC Neurosci

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BackgroundBone Morphogenetic Protein 4 (BMP4) is a diffusible factor which regulates embryonic taste organ development. However, the role of BMP4 in taste buds of adult mice is unknown. We utilized transgenic mice with LacZ under the control of the BMP4 promoter to reveal the expression of BMP4 in the tongues of adult mice. Further we evaluate the pattern of BMP4 expression with that of markers of specific taste bud cell types and cell proliferation to define and compare the cell populations expressing BMP4 in anterior (fungiform papillae) and posterior (circumvallate papilla) tongue.ResultsBMP4 is expressed in adult fungiform and circumvallate papillae, i.e., lingual structures composed of non-taste epithelium and taste buds. Unexpectedly, we find both differences and similarities with respect to expression of BMP4-driven ß-galactosidase. In circumvallate papillae, many fusiform cells within taste buds are BMP4-ß-gal positive. Further, a low percentage of BMP4-expressing cells within circumvallate taste buds is immunopositive for markers of each of the three differentiated taste cell types (I, II and III). BMP4-positive intragemmal cells also expressed a putative marker of immature taste cells, Sox2, and consistent with this finding, intragemmal cells expressed BMP4-ß-gal within 24 hours after their final mitosis, as determined by BrdU birthdating. By contrast, in fungiform papillae, BMP4-ß-gal positive cells are never encountered within taste buds. However, in both circumvallate and fungiform papillae, BMP4-ß-gal expressing cells are located in the perigemmal region, comprising basal and edge epithelial cells adjacent to taste buds proper. This region houses the proliferative cell population that gives rise to adult taste cells. However, perigemmal BMP4-ß-gal cells appear mitotically silent in both fungiform and circumvallate taste papillae, as we do not find evidence of their active proliferation using cell cycle immunomarkers and BrdU birthdating.ConclusionOur data suggest that intragemmal BMP4-ß-gal cells in circumvallate papillae are immature taste cells which eventually differentiate into each of the 3 taste cell types, whereas perigemmal BMP4-ß-gal cells in both circumvallate and fungiform papillae may be slow cycling stem cells, or belong to the stem cell niche to regulate taste cell renewal from the proliferative cell population.

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Section: Discussioncontrasting

confidence: 54%

Differential expression of a BMP4 reporter allele in anterior fungiform versus posterior circumvallate taste buds of mice

Nguyen

Barlow

2010

BMC Neurosci

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“…When it is activated by stress, p53 characteristically functions to stall cell division. However, p53 in mouse tongue cannot be functioning to stall cell division, because p53 is restricted to intragemmal cells that do not divide (Farbman, 1980;Zhang et al, 1995). We conclude that,…”

Section: Implications Of P53 Expression In Postmitotic Taste Cellsmentioning

confidence: 76%

p53 and Bax: Putative death factors in taste cell turnover

Zeng

Oakley

1999

J. Comp. Neurol.

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The turnover of cells in renewing epithelia presents an opportunity to examine cell death pathways in adult vertebrates. In mouse lingual epithelium a typical taste receptor cell survives for 9 days, until it is killed by an unknown cascade of death factors. Apoptosis was implicated by the presence of fragmented DNA in about 8% of taste receptor cells in the vallate papilla. In using immunocytochemistry to seek putative death factors, we observed that squamous epithelial cells of the tongue were negative for Bax, a death factor in the Bcl-2 family of survival/death factors, and were also negative for p53, a tumor-suppressor protein linked to apoptosis and Bax transcription. In contrast, 8-10% of the taste receptor cells were Bax-positive, and 9-11% were p53 positive. These immunopositive taste receptor cells were more likely to display death-related morphologic defects than other receptor cells, and they frequently coexpressed p53 and Bax. In both neonatal and adult mice, the labeling of dividing cells with 5-bromo-2Ј-deoxyuridine indicated that all Bax-positive taste cells were at least 5 days old. On postnatal day 7, when few taste cells were old, no more than 1% of taste cells were immunopositive for either p53 or Bax. We inferred that old taste receptor cells employ p53 and Bax as part of their apoptotic death pathway. The routine expression of p53 by postmitotic, aged taste cells broadens the conventional view that p53 is restricted to mitotic cells that have stress-damaged DNA. Furthermore, the scattered distribution of aged receptor cells within the taste bud excludes some explanations for stable taste signals during receptor cell turnover.

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“…1H). Additionally, we compared the expression of cytokeratin 8 (K8; Krt8 -Mouse Genome Informatics), a marker of immature taste bud cells (Mbiene and Roberts, 2003;Zhang et al, 1995). At E18.5, K8…”

Section: Resultsmentioning

confidence: 99%

ß-Catenin signaling regulates temporally discrete phases of anterior taste bud development

Thirumangalathu

Barlow

2015

Development

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The sense of taste is mediated by multicellular taste buds located within taste papillae on the tongue. In mice, individual taste buds reside in fungiform papillae, which develop at mid-gestation as epithelial placodes in the anterior tongue. Taste placodes comprise taste bud precursor cells, which express the secreted factor sonic hedgehog (Shh) and give rise to taste bud cells that differentiate around birth. We showed previously that epithelial activation of β-catenin is the primary inductive signal for taste placode formation, followed by taste papilla morphogenesis and taste bud differentiation, but the degree to which these later elements were direct or indirect consequences of β-catenin signaling was not explored. Here, we define discrete spatiotemporal functions of β-catenin in fungiform taste bud development. Specifically, we show that early epithelial activation of β-catenin, before taste placodes form, diverts lingual epithelial cells from a taste bud fate. By contrast, β-catenin activation a day later within Shh + placodes, expands taste bud precursors directly, but enlarges papillae indirectly. Further, placodal activation of β-catenin drives precocious differentiation of Type I glial-like taste cells, but not other taste cell types. Later activation of β-catenin within Shh + precursors during papilla morphogenesis also expands taste bud precursors and accelerates Type I cell differentiation, but papilla size is no longer enhanced. Finally, although Shh regulates taste placode patterning, we find that it is dispensable for the accelerated Type I cell differentiation induced by β-catenin.

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Keratin 18 is associated with a subset of older taste cells in the rat

Cited by 50 publications

References 29 publications

Differential expression of a BMP4 reporter allele in anterior fungiform versus posterior circumvallate taste buds of mice

Differential expression of a BMP4 reporter allele in anterior fungiform versus posterior circumvallate taste buds of mice

p53 and Bax: Putative death factors in taste cell turnover

ß-Catenin signaling regulates temporally discrete phases of anterior taste bud development

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