The renal papilla is a niche for adult kidney stem cells
Juan A. Oliver, … , Timothy P. Martens, Qais Al-Awqati
Juan A. Oliver, … , Timothy P. Martens, Qais Al-Awqati
Published September 15, 2004
Citation Information: J Clin Invest. 2004;114(6):795-804. https://doi.org/10.1172/JCI20921.
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Article Nephrology

The renal papilla is a niche for adult kidney stem cells

Abstract

Many adult organs contain stem cells, which are pluripotent and are involved in organ maintenance and repair after injury. In situ, these cells often have a low cycling rate and locate in specialized regions (niches). To detect such cells in the kidney, we administered a pulse of the nucleotide bromodeoxyuridine (BrdU) to rat and mouse pups and, after a long (more than 2-month) chase, examined whether the kidney contained a population of low-cycling cells. We found that in the adult kidney, BrdU-retaining cells were very sparse except in the renal papilla, where they were numerous. During the repair phase of transient renal ischemia, these cells entered the cell cycle and the BrdU signal quickly disappeared from the papilla, despite the absence of apoptosis in this part of the kidney. In vitro isolation of renal papillary cells showed them to have a plastic phenotype that could be modulated by oxygen tension and that when injected into the renal cortex, they incorporated into the renal parenchyma. In addition, like other stem cells, papillary cells spontaneously formed spheres. Single-cell clones of these cells coexpressed mesenchymal and epithelial proteins and gave rise to myofibroblasts, cells expressing neuronal markers, and cells of uncharacterized phenotype. These data indicate that the renal papilla is a niche for adult kidney stem cells.

Authors

Juan A. Oliver, Omar Maarouf, Faisal H. Cheema, Timothy P. Martens, Qais Al-Awqati

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Characterization of renal papillary cell clones. (A) As the example show...
Characterization of renal papillary cell clones. (A) As the example shows, many cells coexpressed mesenchymal proteins such as α-smooth muscle actin (left) as well as epithelial proteins such as ZO-1 (right). (B) In standard control conditions in the absence of sera, all cells were spindle-shaped and stained strongly for α-smooth muscle actin (Control; left) but when LIF was added to the media, two phenotypes were apparent (+ LIF; right): the majority of cells grew in a monolayer and were negative for α-smooth muscle actin (nuclei stained with 10 nM Sytox green), but a few cells grew on top of the monolayer of cells, were spindle-shaped, and expressed α-smooth muscle actin. (C) In standard control culture conditions, a small number of cells expressed the intermediate filament nestin. Occasional cells also expressed the neuronal marker class III β-tubulin (III-β-tubulin) and some cells even acquired the morphological characteristics of neurons. Scale bars: A, 20 μm; B and C, 50 μm.