Isolation of adult rat kidney derived stem cells and differentiation into podocyte-like cells

Studies have shown that adult stem cells can be isolated from different organs. However, no agreement has yet been reached on the identification of adult kidney stem cells. In this study, we have shown that the adult rat kidney contains a population of stem cells that are isolatable and, under suitable culture conditions, these stem cells can differentiate into podocyte. Six adult Wistar rats were used in the present study. Their kidneys were chopped and exposed to collagenase I. Then, with passing through 100 µm mesh, single cells in filtered fraction were cultured in a proliferation medium. After 4 passages, the cells were analyzed by flow cytometry, differentiation and gene expression. Morphological analyses revealed that isolated cells are spindle-shaped, and can differentiate into osteocytes and adipocytes. Flow cytometry demonstrated that these cells expressed cell surface markers CD44, CD90, CD133, c-kit, Pax-2, Oct4, sca-1 and vimentin significantly. Also, the high expression of Wt-1 and Wnt-4 genes was seen in these cells. Moreover, expression of synaptopodin and podocalyxin genes showed differentiation of stem cells into podocyte cells. Our findings demonstrate that isolated cells from the kidney of adult rats are mesenchymal stem cells or progenitor cells and can differentiate to podocyte-like cells.