Cell-intrinsic differences between human tracheal epithelial cells from children and adults [FACS-sorted basal cells]

The airway epithelium is a key protective barrier whose integrity is preserved by the self-renewal and differentiation of basal progenitor cells. Epithelial cells are central to the pathogenesis of multiple chronic lung diseases for which age is a principle risk factor. Children are also less susceptible to SARS-CoV-2 infection, suffer less severe symptoms than adults and have a lower rate of mortality. Few studies have addressed differences between airway epithelial cells in children and adults. Here, we perform bulk RNA sequencing studies in laser-captured whole epithelium, FACS-sorted basal cells and cultured basal cells, as well as in vitro cell proliferation experiments, to address the intrinsic molecular differences between paediatric and adult airway basal cells. We find that, while the cellular composition of the paediatric and adult tracheal epithelium is broadly similar, in cell culture, paediatric airway epithelial cells displayed higher colony forming ability, better in vitro growth and outcompeted adult cells in competitive proliferation assays. Although recurring differences between airway epithelial gene expression were seen between samples from children and adults, RNA sequencing showed broad conservation of transcriptional programmes. Genes associated with SARS-CoV-2 infection were not differentially expressed between children and adults, although individuals showed some variability in their expression of viral infection-associated genes. Our results chart important cell intrinsic differences in transcriptional profile and regenerative capacity between tracheal epithelial cells of children and adults. Overall design: Comparison of airway RNAseq data between adults and children. Three related datasets are presented: fresh airway epithelial cells, fresh sorted basal cells and cultured basal cells. This dataset contains FACS-sorted basal cells.

气道上皮是机体关键的保护屏障，其完整性通过基底祖细胞的自我更新与分化得以维持。上皮细胞是多种慢性肺部疾病发病机制的核心环节，而年龄是这类疾病的主要危险因素。儿童感染新冠病毒（SARS-CoV-2）的易感性更低，临床症状较成人更轻微，且死亡率也更低。目前针对儿童与成人气道上皮细胞之间差异的研究尚不多见。本研究针对激光捕获的全层上皮细胞、经荧光激活细胞分选（Fluorescence Activated Cell Sorting, FACS）得到的基底细胞以及体外培养的基底细胞开展批量RNA测序（bulk RNA sequencing），并结合体外细胞增殖实验，探究儿童与成人气道基底细胞的内在分子差异。研究发现，尽管儿童与成人气管上皮的细胞组成整体相似，但在细胞培养体系中，儿童气道上皮细胞展现出更高的集落形成能力、更优异的体外生长状态，且在竞争性增殖实验中可优于成人细胞。尽管儿童与成人的样本间存在反复出现的气道上皮基因表达差异，但RNA测序结果显示转录程序整体保守。与新冠病毒感染相关的基因在儿童与成人之间未呈现差异表达，不过个体间病毒感染相关基因的表达存在一定差异。本研究揭示了儿童与成人气管上皮细胞在转录谱与再生能力上存在重要的细胞内在差异。总体设计：本研究对比了成人与儿童的气道RNA测序数据，共包含三个相关数据集：新鲜气道上皮细胞、新鲜分选的基底细胞以及体外培养的基底细胞，本数据集包含经荧光激活细胞分选的基底细胞样本。