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 SOX10 (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 SOX10-expressing cells using SOX10-Cre, a Cre model driven by the endogenous SOX10 promoter, crossing with a Cre reporter line R26-tdTomato (tdT), we found SOX10-Cre-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—SOX10-Cre-labeled cells in the connective tissue core and/or von Ebner's glands.

中文翻译：

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舌头上皮下的SOX10-Cre标签细胞用作味蕾细胞的祖细胞，这些味蕾细胞主要是III型和角蛋白8级。

味蕾细胞是经过持续更新的专门上皮细胞，因此需要活性祖细胞进行更新和完整的味觉功能。我们以前的研究表明，味蕾细胞群起源于周围的舌头上皮细胞-以前被认为是味蕾祖细胞的唯一来源。在这项研究中，我们证明了已知在迁移的神经RY中表达SOX10（SRY相关的HMG-box基因10）的细胞也分布在舌上皮下围绕味蕾的组织隔室中，即味觉乳头和冯·埃伯纳氏腺的结缔组织核心。通过使用SOX10-Cre（Cre）对表达SOX10的细胞进行谱系追踪由内源性SOX10启动子驱动的模型，与Cre报告基因系R26-tdTomato（tdT）交叉，我们发现在所有三种类型的味乳头（真菌形，环戊酸和叶形）中，味蕾内有SOX10-Cre标记的tdT ⁺细胞以及产后小鼠的软pa。在发育阶段，tdT ⁺味蕾细胞逐渐丰富，从出生时的几乎为零到成人的35％以上。大多数tdT ⁺味蕾细胞的角蛋白8（一种广泛使用的味蕾细胞标记物）的免疫信号强度较低。在周缘味蕾中，tdT信号主要与III型味蕾细胞标记共定位，而与I和II型细胞标记物共定位。总之，我们的数据证明了产后小鼠味蕾的新型祖细胞-结缔组织核心和/或冯·埃伯纳腺中SOX10 - Cre标记的细胞。