Transcriptional Analysis of T Cells Resident in Human Skin

Human skin contains various populations of memory T cells in permanent residence and in transit. Arguably, the best characterized of the skin subsets are the CD8+ permanently resident memory T cells (TRM) expressing the integrin subunit, CD103. In order to investigate the remaining skin T cells, we isolated skin-tropic (CLA+) helper T cells, regulatory T cells, and CD8+ CD103- T cells from skin and blood for RNA microarray analysis to compare the transcriptional profiles of these groups. We found that despite their common tropism, the T cells isolated from skin were transcriptionally distinct from blood-derived CLA+ T cells. A shared pool of genes contributed to the skin/blood discrepancy, with substantial overlap in differentially expressed genes between each T cell subset. Gene set enrichment analysis further showed that the differential gene profiles of each human skin T cell subset were significantly enriched for previously identified TRM core signature genes. Our results support the hypothesis that human skin may contain additional TRM or TRM-like populations.

人类皮肤中存在多种记忆T细胞群，其中一部分永久驻留于皮肤，另一部分则循环转运于体内。目前研究最为透彻的皮肤T细胞亚群，当属表达整合素亚基CD103的CD8+常驻记忆T细胞（TRM）。为探究其余皮肤T细胞亚群，我们从皮肤与血液中分离出皮肤归巢（CLA+）辅助性T细胞、调节性T细胞以及CD8+ CD103- T细胞，通过RNA微阵列分析比较各组细胞的转录谱。研究发现，尽管这些T细胞均具有皮肤归巢特性，但从皮肤分离得到的T细胞在转录层面与血液来源的CLA+ T细胞存在显著差异。导致皮肤与血液来源T细胞转录差异的基因存在共有基因集，且各T细胞亚群的差异表达基因存在大量重叠。基因集富集分析进一步显示，各人类皮肤T细胞亚群的差异基因谱均显著富集于此前已确认的TRM核心特征基因集。本研究结果支持如下假说：人类皮肤中或许存在额外的TRM或类TRM细胞群。