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The mechanism upon which human kidneys undergo regeneration is debated, though different lineage-tracing mouse models have tried to explain the cellular types and the mechanisms involved. Different sources of human renal progenitors have been proposed, but it is difficult to argue whether these populations have the same capacities that have been described in mice. Using the nephrosphere (NS) model, we isolated the quiescent population of adult human renal stem-like PKH high /CD133+/CD24- cells (RSC). The aim of this study was to deepen the RSC in vitro multipotency capacity. RSC, not expressing endothelial markers, generated secondary nephrospheres containing CD31+/vWf+ cells and cytokeratin positive cells, indicating the coexistence of endothelial and epithelial commitment. RSC cultured on decellularized human renal scaffolds generated endothelial structures together with the proximal and distal tubular structures. CD31+ endothelial committed progenitors sorted from nephrospheres generated spheroids with endothelial-like sprouts in Matrigel. We also demonstrated the double commitment toward endothelial and epithelial lineages of single RSC. The ability of the plastic RSC population to recapitulate the development of tubular epithelial and endothelial renal lineages makes these cells a good tool for the creation of organoids with translational relevance for studying the parenchymal and endothelial cell interactions and developing new therapeutic strategies.

In end-stage chronic kidney disease, the option of organ transplantation is limited because of the scarce availability of kidneys. The combination of stem cell research, regenerative medicine, and tissue engineering seems a promising approach to produce new transplantable kidneys. Currently, the possibility to repopulate naturally obtained scaffolds with cells of different sources is advancing. Our aim was to test, for the first time, whether the nephrosphere (NS) cells, composed by renal stem/progenitor-like cells, were able to repopulate different nephron portions of renal extracellular matrix scaffolds obtained after decellularization of human renal tissue slices. Our decellularization protocol enabled us to obtain a completely acellular renal scaffold while maintaining the extracellular matrix structure and composition in terms of collagen IV, laminin, and fibronectin. NS cells, cultured on decellularized renal scaffolds with basal medium, differentiated into proximal and distal tubules as well as endothelium, as highlighted by histology and by the specific expression of epithelial cytokeratin 8.18, proximal tubular CD10, distal tubular cytokeratin 7, and endothelial von Willebrand factor markers. Endothelial medium promoted the differentiation toward the endothelium, whereas epithelial medium promoted the differentiation toward the epithelium. NS cells seem to be a good tool for scaffold repopulation, paving the way for experimental investigations focused on whole-kidney reconstruction., (Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

The existence and identification of adult renal stem cells is a controversial issue. In this study, renal stem cells were identified from cultures of clonal human nephrospheres. The cultured nephrospheres exhibited the activation of stem cell pathways and contained cells at different levels of maturation. In each nephrosphere the presence of 1.12-1.25 cells mirroring stem cell properties was calculated. The nephrosphere cells were able to generate three-dimensional tubular structures in 3D cultures and in vivo. In clonal human nephrospheres a PKH(high) phenotype was isolated using PKH26 epifluorescence, which can identify quiescent cells within the nephrospheres. The PKH(high) cells, capable of self-renewal and of generating a differentiated epithelial, endothelial and podocytic progeny, can also survive in vivo maintaining the undifferentiated status. The PKH(high) status, together with a CD133(+)/CD24(-) phenotype, identified a homogeneous cell population displaying in vitro self-renewal and multipotency capacity. The resident adult renal stem cell population isolated from nephrospheres can be used for the study of mechanisms that regulate self-renewal and differentiation in adult renal tissue as well as in renal pathological conditions., (© 2013.)

Renal cell carcinoma (RCC) tissue is composed of a mixture of neoplastic and normal cells, which complicate proteome analysis. The aim of our study was to investigate whether it is feasible to establish primary cell cultures of RCC and of renal cortex maintaining the tissue phenotype along with a more homogeneous and enriched cytological material. Fourteen (82.3%) primary cultures from 17 surgical cases were established and characterized by morphology, growth rate, immunocytochemistry, and molecular analysis performed by Real-time PCR, Western blotting, two-dimensional electrophoresis (2-DE), and mass spectrometry. Cultures showed >90% cytokeratine-positive epithelial cells. In primary tumor cultures, the molecular phenotype of manganese superoxide dismutase and heat shock protein 27 was the same as that found in tumor tissues with overexpression and increased number of isoforms. Moreover, 27 out 28 specific proteins and their isoforms, present in spots excised from 2-DE gel of cortex or RCC cultures, corresponded to those identified on the 2-DE tissue cortex reference map, suggesting that these primary cultures retain the proteomic profile of the corresponding tissues.

The mechanism upon which human kidneys undergo regeneration is debated, though different lineage-tracing mouse models have tried to explain the cellular types and the mechanisms involved. Different sources of human renal progenitors have been proposed, but it is difficult to argue whether these populations have the same capacities that have been described in mice. Using the nephrosphere (NS) model, we isolated the quiescent population of adult human renal stem-like PKHhigh/CD133+/CD24− cells (RSC). The aim of this study was to deepen the RSC in vitro multipotency capacity. RSC, not expressing endothelial markers, generated secondary nephrospheres containing CD31+/vWf+ cells and cytokeratin positive cells, indicating the coexistence of endothelial and epithelial commitment. RSC cultured on decellularized human renal scaffolds generated endothelial structures together with the proximal and distal tubular structures. CD31+ endothelial committed progenitors sorted from nephrospheres generated spheroids with endothelial-like sprouts in Matrigel. We also demonstrated the double commitment toward endothelial and epithelial lineages of single RSC. The ability of the plastic RSC population to recapitulate the development of tubular epithelial and endothelial renal lineages makes these cells a good tool for the creation of organoids with translational relevance for studying the parenchymal and endothelial cell interactions and developing new therapeutic strategies. [ABSTRACT FROM AUTHOR]