Restoration of barrier-tissue integrity after injury is dependent on the function of immune cells and stem cells (SCs) residing in the tissue. In response to skin injury, hair-follicle stem cells (HFSCs), normally poised for hair generation, are recruited to the site of injury and differentiate into cells that repair damaged epithelium. We used a SC fate-mapping approach to examine the contribution of regulatory T (Treg) cells to epidermal-barrier repair after injury. Depletion of Treg cells impaired skin-barrier regeneration and was associated with a Th17 inflammatory response and failed HFSC differentiation. In this setting, damaged epithelial cells preferentially expressed the neutrophil chemoattractant CXCL5, and blockade of CXCL5 or neutrophil depletion restored barrier function and SC differentiation after epidermal injury. Thus, Treg-cell regulation of localized inflammation enables HFSC differentiation and, thereby, skin-barrier regeneration, with implications for the maintenance and repair of other barrier tissues.

损伤后屏障组织完整性的恢复取决于存在于组织中的免疫细胞和干细胞 (SC) 的功能。为了应对皮肤损伤，通常准备生发的毛囊干细胞 (HFSC) 被募集到损伤部位并分化为修复受损上皮细胞的细胞。我们使用 SC 命运映射方法来检查调节性 T (Treg) 细胞对损伤后表皮屏障修复的贡献。Treg 细胞的耗竭会损害皮肤屏障再生，并与 Th17 炎症反应和 HFSC 分化失败有关。在这种情况下，受损的上皮细胞优先表达中性粒细胞趋化因子 CXCL5，而阻断 CXCL5 或中性粒细胞耗竭可恢复表皮损伤后的屏障功能和 SC 分化。因此，