Lgr5+ve stem cells in nephrogenesis

Multipotent stem cells and their lineage-restricted progeny drive nephron formation within the developing kidney. Validated markers of these early stem/progenitor populations are essential for deciphering their in vivo function and for evaluating their clinical potential for treating adult kidney disease. Here, we document expression of the adult stem cell marker Lgr5 in the developing kidney and assess the stem/progenitor identity of Lgr5+ve cells via in vivo lineage tracing. The appearance and localization of Lgr5+ve cells coincided with that of the S-shaped body around E14. Lgr5 expression remained restricted to cell clusters within developing nephrons in the cortex until P7, when expression was permanently silenced. In vivo lineage tracing identified Lgr5 as a marker of a novel progenitor population within nascent nephrons dedicated to generating the thick ascending limb of Henle's loop and distal convoluted tubule. The Lgr5 surface marker and experimental models described here will be invaluable for deciphering the contribution of early nephron stem cells to developmental defects and for isolating human nephron progenitors as a prerequisite to evaluating their therapeutic potential. Metanephric kidneys of timed pregnancies of ~14 days of gestation were harvested and cultured for ~10 days. Lgr5-EGFP-Ires-CreERT2-positive embryonic kidneys were identified by fluorescence microscopy and enzymatically digested to a single cell solution. GFPhi and GFPneg cells were sorted by flow cytometry (MoFlo; Dako). RNA, isolated using RNeasy (Qiagen), was analyzed using the Affymetrix platform.