Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States.
Am J Physiol Gastrointest Liver Physiol. 2024 Feb 1;326(2):G107-G119. doi: 10.1152/ajpgi.00108.2023. Epub 2023 Nov 21.
Nucleotides are potent extracellular signaling molecules during homeostasis, infection, and injury due to their ability to activate purinergic receptors. The nucleotide ATP activates P2X receptors (P2RXs), whereas the nucleotides ADP, ATP, UTP, and UDP-glucose selectively activate different P2Y receptors (P2RYs). Several studies have established crucial roles for P2 receptors during intestinal inflammatory and infectious diseases, yet the most extensive characterization of purinergic signaling has focused on immune cells and the central and enteric nervous systems. As epithelial cells serve as the first barrier against irritants and infection, we hypothesized that the gut epithelium may express multiple purinergic receptors that respond to extracellular nucleotide signals. Using the Human Protein Atlas and Gut Cell Survey, we queried single-cell RNA sequencing (RNAseq) data for the P2 purinergic receptors in the small and large intestines. In silico analysis reveals robust mRNA expression of P2RY1, P2RY2, P2RY11, and P2RX4 throughout the gastrointestinal tract. Human intestinal organoids exhibited a similar expression pattern with a prominent expression of P2RY1, P2RY2, and P2RX4, but this purinergic receptor repertoire was not conserved in T84, Caco2, and HT29 intestinal epithelial cell lines. Finally, P2YR1 and P2YR2 agonists elicited robust calcium responses in human intestinal organoids, but calcium responses were weaker or absent in the cell lines. These findings suggest that the gastrointestinal epithelia respond to extracellular purinergic signaling via P2RY1, P2RY2, P2RY11, and P2RX4 receptors and highlight the benefit of using intestinal organoids as a model of intestinal purinergic signaling. Several studies have revealed crucial roles for P2 receptors during inflammatory and infectious diseases, however, these have largely been demonstrated in immune cells and the enteric nervous system. Although epithelial cells serve as the first barrier against infection and inflammation, the role of purinergic signaling within the gastrointestinal tract remains largely unknown. This work expands our knowledge of purinergic receptor distribution and relative expression along the intestine.
核苷酸是体内平衡、感染和损伤过程中有效的细胞外信号分子，这是由于它们能够激活嘌呤能受体。核苷酸 ATP 激活 P2X 受体（P2RXs），而核苷酸 ADP、ATP、UTP 和 UDP-葡萄糖则选择性地激活不同的 P2Y 受体（P2RYs）。几项研究已经确定了 P2 受体在肠道炎症和感染性疾病中的关键作用，但对嘌呤能信号转导的最广泛描述集中在免疫细胞和中枢及肠神经系统。由于上皮细胞是抵御刺激物和感染的第一道屏障，我们假设肠道上皮可能表达多种嘌呤能受体，以响应细胞外核苷酸信号。我们使用人类蛋白质图谱和肠道细胞调查，在小肠和大肠的单细胞 RNA 测序 (RNAseq) 数据中查询 P2 嘌呤能受体。计算机分析显示，P2RY1、P2RY2、P2RY11 和 P2RX4 在胃肠道中均有丰富的 mRNA 表达。人类肠道类器官表现出相似的表达模式，其中 P2RY1、P2RY2 和 P2RX4 的表达尤为明显，但这种嘌呤能受体谱在 T84、Caco2 和 HT29 肠道上皮细胞系中并不保守。最后，P2YR1 和 P2YR2 激动剂在人类肠道类器官中引起强烈的钙反应，但在细胞系中反应较弱或不存在。这些发现表明，胃肠道上皮通过 P2RY1、P2RY2、P2RY11 和 P2RX4 受体对细胞外嘌呤能信号做出反应，并强调了使用肠道类器官作为肠道嘌呤能信号模型的益处。几项研究已经揭示了 P2 受体在炎症和感染性疾病中的关键作用，然而，这些主要是在免疫细胞和肠神经系统中得到证实的。尽管上皮细胞是抵御感染和炎症的第一道屏障，但嘌呤能信号在胃肠道中的作用在很大程度上仍是未知的。这项工作扩展了我们对沿肠道分布的嘌呤能受体分布和相对表达的认识。
