【Background】The gastrointestinal tract is a barrier between the outside environment and the inside of the organism and is home to an enormous amount of symbiotic bacteria. In addition, various substances derived from bacteria have been shown to influence biological functions. ATP is one of such substance released by bacteria in the digestive tract, and it is known to modulate colonic immune cell functions via the ionotropic P2X4 receptor (P2X4R). However, role of P2X4R in colonic epithelial cells has not been known. Therefore, we analyzed role of P2X4R in colonic epithelial cells.
【Method】We obtained single cell RNA sequence (scRNA-seq) data (GSE148693) from NCBI GEO and analyzed cells expressing P2X4R using Seurat. DNA microarrays were used to identify genes in the colon whose expression is altered by P2X4R deficiency. The expression of P2X4R in colon was investigated by immunostaining.
【Results】scRNA-seq analysis revealed that the P2X4R is expressed in the secretory cell lineage expressing Atoh1 and Muc2. Various gene expressions were altered in the colon of P2X4R-deficient mice compared to that of wild-type mice. Among them Reg4 was expressed in P2X4R-expressing cells. Reg4 has been reported as a marker or deep crypt secretory (DCS) cells, which constitute the tem cell niche in the colon. The expression level of Relm-β, another marker for DCS cells, was also elevated in P2X4R deficient mice. These results suggest that the P2X4R may be involved in the regulation of a stem cell niche in colon epithelial cells.