Tonicity drives collecting duct maturation in the mammalian kidney.

High tonicity, primarily through NFAT5 activation, drives morphological, transcriptional, and functional maturation of mammalian kidney medullary collecting ducts.

• Why it matters: Understanding how environmental factors influence kidney maturation can improve organoid development and regenerative therapies, addressing gaps in replicating in vivo organogenesis.
• What they did: Researchers demonstrated that elevated salt levels promote CD maturation both in vitro and in vivo, and combined this with hormones to develop a protocol for human medullary CD organoids, including functional water permeability assays.
• The result: This work shows that high tonicity enhances kidney maturation processes, enabling disease modeling and advancing organoid-based treatments for kidney disorders.