Interaction between adult stem cells and their progeny is critical for tissue homeostasis and regeneration. In multiple organs, mesenchymal stem cells (MSCs) give rise to transit amplifying cells (TACs), which then differentiate into different cell types. However, whether and how MSCs interact with TACs remains unknown. Using the adult mouse incisor as a model, we present in vivo evidence that TACs and MSCs have distinct genetic programs and engage in reciprocal signaling cross talk to maintain tissue homeostasis. Specifically, an IGF-WNT signaling cascade is involved in the feedforward from MSCs to TACs. TACs are regulated by tissue-autonomous canonical WNT signaling and can feedback to MSCs and regulate MSC maintenance via Wnt5a/Ror2-mediated non-canonical WNT signaling. Collectively, these findings highlight the importance of coordinated bidirectional signaling interaction between MSCs and TACs in instructing mesenchymal tissue homeostasis, and the mechanisms identified here have important implications for MSC–TAC interaction in other organs.

中文翻译：

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间充质干细胞和转运放大细胞之间的相互作用调节组织稳态

成体干细胞与其后代之间的相互作用对于组织稳态和再生至关重要。在多个器官中，间充质干细胞 (MSC) 会产生转运扩增细胞 (TAC)，然后分化成不同的细胞类型。然而，MSCs 是否以及如何与 TACs 相互作用仍然未知。使用成年小鼠门牙作为模型，我们提供了体内证据，表明 TAC 和 MSC 具有不同的遗传程序并参与相互信号交叉对话以维持组织稳态。具体来说，从 MSC 到 TAC 的前馈涉及 IGF-WNT 信号级联。TACs 受组织自主的经典 WNT 信号调节，可以反馈给 MSC，并通过 Wnt5a/Ror2 介导的非经典 WNT 信号调节 MSC 维持。集体，