Axial Nephron Fate Switching Demonstrates a Plastic System Tunable on Demand [RNA-seq]

The human nephron is a highly patterned tubular structure. Approximately 1 million nephrons form in each kidney during embryonic and fetal development and develop specialized cells that regulate bodily fluid homeostasis, blood pressure, and urine secretion throughout life. This raises the question of how these cells originally develop. Here we interrogate early human nephron patterning using an iPSC-based kidney organoid system that generates hundreds of developmentally synchronized nephron structures. We show that human nephron patterning is controlled by integrated WNT/BMP/FGF signaling. Imposing a WNThigh/BMPlow state established a distal identity that matures into thick ascending loop of Henle cell identities by activating FGF. Simultaneous suppression of FGF signaling reverts cells to a proximal cell-state, thereby indicating the dependence on FGF signaling for distal cell formation in the human nephron. Our system highlights plasticity in nephron identities and mechanisms controlling normal patterning.