Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA.
Stem Cells Dev. 2020 May 15;29(10):638-647. doi: 10.1089/scd.2020.0022. Epub 2020 Mar 24.
Taste bud cells are specialized epithelial cells that undergo continuous turnover, and thus require active progenitors for their renewal and an intact taste function. Our previous studies suggested that a population of taste bud cells originates from outside of the surrounding tongue epithelium-previously regarded sole source of taste bud progenitors. In this study, we demonstrated that (SRY-related HMG-box gene 10)-expressing cells, known to be in the migrating neural crest, were also distributed in taste bud-surrounding tissue compartments under the tongue epithelium, that is, the connective tissue core of taste papillae and von Ebner's glands. By lineage tracing of -expressing cells using , a model driven by the endogenous promoter, crossing with a reporter line R26-tdTomato (tdT), we found -labeled tdT cells within taste buds in all three types of taste papillae (fungiform, circumvallate, and foliate) as well as in the soft palate in postnatal mice. The tdT taste bud cells were progressively more abundant along the developmental stages, from virtually zero at birth to over 35% in adults. Most of tdT taste bud cells had a low intensity of immunosignals of Keratin 8 (a widely used taste bud cell marker). In circumvallate taste buds, tdT signals were co-localized principally with a type III taste bud cell marker, less so with type I and II cell makers. Together, our data demonstrate a novel progenitor source for taste buds of postnatal mice--labeled cells in the connective tissue core and/or von Ebner's glands.
味蕾细胞是特化的上皮细胞，经历持续的更新，因此需要活跃的祖细胞来进行更新和完整的味觉功能。我们之前的研究表明，一部分味蕾细胞起源于周围舌上皮细胞之外——之前被认为是味蕾祖细胞的唯一来源。在这项研究中，我们证明了（SRY 相关高迁移率族盒基因 10）表达细胞，已知存在于迁移的神经嵴中，也分布在舌上皮细胞下方的味蕾周围组织隔室中，即味觉乳头和 Ebner 腺的结缔组织核心。通过使用表达细胞的谱系追踪，利用内源性启动子驱动的模型，与一个报告线 R26-tdTomato（tdT）进行杂交，我们在所有三种类型的味觉乳头（菌状乳头、轮廓乳头和叶状乳头）以及出生后小鼠的软腭中发现了标记的 tdT 细胞存在于味觉中。在发育阶段，tdT 味觉细胞逐渐增多，从出生时几乎为零到成年时超过 35%。大多数 tdT 味觉细胞的角蛋白 8 免疫信号强度较低（角蛋白 8 是一种广泛用于味觉细胞标记的标志物）。在轮廓乳头中，tdT 信号主要与 III 型味觉细胞标志物共定位，与 I 型和 II 型细胞标志物的共定位较少。总之，我们的数据表明，出生后小鼠的味蕾有一个新的祖细胞来源——连接组织核心和/或 Ebner 腺中的标记细胞。
