YFP+PDGFRa+ and YFP+PDGFRa– stromal cells isolated from the small intestine of LTBRfloxedPDGFRa/YFP mice

After birth, the intestine undergoes major changes to shift from an immature proliferative state to a functional intestinal barrier. By combining inducible lineage tracing and transcriptomics in mouse models, we identify a pro-differentiation PDGFRαHigh intestinal stromal lineage originating from postnatal LTβR+ perivascular stromal progenitors. Genetic blockage of this lineage increased the intestinal stem cells pool while decreasing epithelial and immune maturation at weaning age, leading to reduced postnatal growth and dysregulated repair responses. Ablating PDGFRα in the LTβR stromal lineage demonstrates that PDGFRα has a major impact on the lineage fate and function, inducing a transcriptomic switch from pro-stemness genes such as Rspo3 and Grem1 to pro-differentiation factors including BMPs, retinoic acid and laminins, and on spatial organization within the crypt-villus and repair responses. Our results show that PDGFRα-induced transcriptomic switch in intestinal stromal cells is required in the first weeks after birth to coordinate postnatal intestinal maturation and function. CD45-CD31- YFP+ stromal cells expressing PDGFRα (YFP+PDGFRα+) or not (YFP+PDGFRα-) were isolated by FACS from the small intestine of LTβRfloxPDGFRα/YFP mice to perform RNA sequencing

出生后，肠道会经历重大转变，从未成熟的增殖状态逐步转向具备完整功能的肠道屏障。本研究通过在小鼠模型中结合诱导型谱系示踪（inducible lineage tracing）与转录组学（transcriptomics）技术，鉴定出一类起源于出生后LTβR阳性（LTβR+）血管周围基质祖细胞的、具有促分化特性的PDGFRα高表达（PDGFRαHigh）肠道基质谱系。该谱系的遗传阻断会在断奶期扩增肠道干细胞池，同时降低上皮细胞与免疫细胞的成熟度，进而导致出生后生长减缓以及修复反应失调。在LTβR阳性基质谱系中敲除PDGFRα的实验证实，PDGFRα对该谱系的命运与功能具有核心调控作用，可诱导转录组发生转向：从Rspo3、Grem1等促干细胞特性基因，切换为BMP家族、视黄酸与层粘连蛋白等促分化因子，并影响隐窝-绒毛结构内的空间组织与修复应答过程。本研究结果表明，在出生后的最初数周内，肠道基质细胞中PDGFRα介导的转录组转向，是协调出生后肠道成熟与正常功能发挥的必要条件。研究人员通过荧光激活细胞分选术（FACS, Fluorescence-Activated Cell Sorting）从LTβRfloxPDGFRα/YFP小鼠的小肠中，分离得到CD45⁻CD31⁻YFP⁺基质细胞的两个亚群：表达PDGFRα的YFP⁺PDGFRα⁺细胞与不表达PDGFRα的YFP⁺PDGFRα⁻细胞，用于开展RNA测序实验。