Tetrameric STAT5 regulates the formation of immune niche cells to protect stem cell regenerative repair against mucosal inflammation.

cell influx post irradiation or colitis. By contrast, depleting tetrameric STAT5 in organoids reduced ISC pluripotency and organoid growth post irradiation. Mechanistically, chromatin immunoprecipitation and single-cell RNA sequencing analyses with crypt cells revealed that depleting STAT5 tetramers decreased STAT5-binding on the Metallothionein 1 (Mt1) locus in crypt T cells and increased Mt1 expression, which leads to T cell migration into crypts and enhanced ISC regeneration. Together, the tetrameric STAT5 suppresses the formation of the crypt T cell niche. Interrupting STAT5 tetramers promotes the expansion of crypt TCRγδ cells, providing a target for promoting ISC regenerative repair during IBD-ulcerative colitis.