PI3K/Akt signaling pathway is essential for de novo hair follicle regeneration
PI3K/Akt signaling pathway is essential for de novo hair follicle regeneration
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DOI：
10.1186/s13287-020-01650-6
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发表时间：
2020-04-03
影响因子：
7.5
通讯作者：
Wu, Yaojiong
中科院分区：
文献类型：
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作者：
Chen, Yu;Fan, Zhimeng;Wu, Yaojiong
背景培养的表皮干细胞（Epi-SC）和皮肤源性前体细胞（SKP）能够在植入后重建功能性毛囊，但调节新生毛囊形成的信号通路却很少被研究。在这项研究中，我们旨在了解皮肤类器官形成过程中 Epi-SC 和 SKP 之间的相互作用，并揭示对毛囊从头再生至关重要的关键信号通路。方法 为了追踪移植后的命运，用 tdTomato 标记新生 C57BL/6 小鼠的 Epi-SC，并从新生 C57BL/6/GFP 小鼠中分离 SKP。将Epi-SCs-tdTomato和SKPs-EGFP在Matrigel中的混合物在培养物中和植入裸鼠切除伤口后在双光子显微镜下观察，以观察细胞在毛囊形态发生过程中的动态迁移。通过 RNA-Seq 分析检查两个细胞群之间的信号通讯。通过使用特定抑制剂靶向该通路来观察毛囊从头形成的功能丧失，从而验证了分析揭示的潜在信号通路。结果双光子显微镜分析表明，当Epi-SCs和SKPs在Matrigel中混合培养时，它们发生动态迁移，形成双层皮肤样结构（皮肤类器官），其中Epi-SCs位于外层；当Epi-SCs和SKPs的混合物被移植到裸鼠的切除伤口中时，第5天就形成了类似表皮和真皮的双层结构，随后从头生成了毛囊。在混合物中孵育后，对两种细胞类型的 RNA-Seq 分析显示基因转录组发生显着变化，其中 Epi-SC 中的 PI3K-Akt 信号通路显着上调；同时，在 SKP 中发现了几种可能激活 PI3K 的生长因子和细胞因子的表达升高，表明它们之间存在活跃的相互通讯。此外，通过特异性抑制剂抑制PI3K或Akt可显着抑制Epi-SCs和SKPs介导的毛囊再生。结论 我们的数据表明 PI3K-Akt 信号通路在毛囊从头再生中发挥着至关重要的作用，这一发现可能表明在增强毛发再生方面具有潜在的治疗应用。
Background Cultured epidermal stem cells (Epi-SCs) and skin-derived precursors (SKPs) were capable of reconstituting functional hair follicles after implantation, while the signaling pathways that regulate neogenic hair follicle formation are poorly investigated. In this study, we aimed to understand the interactions between Epi-SCs and SKPs during skin organoid formation and to uncover key signal pathways crucial for de novo hair follicle regeneration. Methods To track their fate after transplantation, Epi-SCs derived from neonatal C57BL/6 mice were labeled with tdTomato, and SKPs were isolated from neonatal C57BL/6/GFP mice. A mixture of Epi-SCs-tdTomato and SKPs-EGFP in Matrigel was observed under two-photon microscope in culture and after implantation into excisional wounds in nude mice, to observe dynamic migrations of the cells during hair follicle morphogenesis. Signaling communications between the two cell populations were examined by RNA-Seq analysis. Potential signaling pathways revealed by the analysis were validated by targeting the pathways using specific inhibitors to observe a functional loss in de novo hair follicle formation. Results Two-photon microscopy analysis indicated that when Epi-SCs and SKPs were mixed in Matrigel and cultured, they underwent dynamic migrations resulting in the formation of a bilayer skin-like structure (skin organoid), where Epi-SCs positioned themselves in the outer layer; when the mixture of Epi-SCs and SKPs was grafted into excisional wounds in nude mice, a bilayer structure resembling the epidermis and the dermis formed at the 5th day, and de novo hair follicles generated subsequently. RNA-Seq analysis of the two cell types after incubation in mixture revealed dramatic alterations in gene transcriptome, where PI3K-Akt signaling pathway in Epi-SCs was significantly upregulated; meanwhile, elevated expressions of several growth factors and cytokine potentially activating PI3K were found in SKPs, suggesting active reciprocal communications between them. In addition, inhibition of PI3K or Akt by specific inhibitors markedly suppressed the hair follicle regeneration mediated by Epi-SCs and SKPs. Conclusions Our data indicate that the PI3K-Akt signaling pathway plays a crucial role in de novo hair follicle regeneration, and the finding may suggest potential therapeutic applications in enhancing hair regeneration.