title: Proliferation and migration of label-retaining cells of the kidney papilla.
abstract: The kidney papilla contains a population of cells with several characteristics of adult stem cells, including the retention of proliferation markers during long chase periods (i.e., they are label-retaining cells [LRCs]). To determine whether the papillary LRCs generate new cells in the normal adult kidney, we examined cell proliferation throughout the kidney and found that the upper papilla is a site of enhanced cell cycling. Using genetically modified mice that conditionally expressed green fluorescence protein fused to histone 2B, we observed that the LRCs of the papilla proliferated only in its upper part, where they associate with "chains" of cycling cells. The papillary LRCs decreased in number with age, suggesting that the cells migrated to the upper papilla before entering the cell cycle. To test this directly, we marked papillary cells with vital dyes in vivo and found that some cells in the kidney papilla, including LRCs, migrated toward other parts of the kidney. Acute kidney injury enhanced both cell migration and proliferation. These results suggest that during normal homeostasis, LRCs of the kidney papilla (or their immediate progeny) migrate to the upper papilla and form a compartment of rapidly proliferating cells, which may play a role in repair after ischemic injury.
authors.affiliation: Department of Medicine, Columbia University, New York, NY 10032, USA. jao7@columbia.edu
authors.forename: Juan A
authors.initials: JA
authors.lastname: Oliver
authors.forename: Apostolos
authors.initials: A
authors.lastname: Klinakis
authors.forename: Faisal H
authors.initials: FH
authors.lastname: Cheema
authors.forename: Jonathan
authors.initials: J
authors.lastname: Friedlander
authors.forename: Rosemary V
authors.initials: RV
authors.lastname: Sampogna
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Martens
authors.forename: Charles
authors.initials: C
authors.lastname: Liu
authors.forename: Argiris
authors.initials: A
authors.lastname: Efstratiadis
authors.forename: Qais
authors.initials: Q
authors.lastname: Al-Awqati
mesh_terms: D000367:Age Factors; D000818:Animals; D002465:Cell Movement; D049109:Cell Proliferation; D007668:Kidney / Q000166:cytology* / Q000254:growth & development; D051381:Rats; D013194:Staining and Labeling