Aligned Nanofiber Topographies Enhance the Differentiation of Adult Renal Stem Cells into Glomerular Podocytes

The use of adult stem/progenitor cells is a challenge in current research about kidney functional regeneration. In this framework, material-induced stem cell differentiation can become a new paradigm to promote advances in therapies. Here, the effects of both isotropic and anisotropic fibrous topographies on the podocyte differentiation of adult renal stem cells (RSCs) from human donors are investigated. The proliferation rate of RSCs is analyzed, immunofluorescence and genetic analyses of specific podocyte markers (Wilms' tumor 1 gene, nephrin, and podocin) are performed to assess the differentiation level on the scaffolds. The studied markers are over-expressed in RSCs cultured on aligned fibers compared to cells cultured on either protein-functionalized films or randomly oriented fibers. In addition, RSCs cultured on aligned fibers are found to differentiate toward podocyte precursors even in basal medium conditions, thus highlighting scaffold-induced commitment without exogenous chemicals or cellular reprogramming. Aligned polymer fiber scaffolds which provide instructive cues for RSC differentiation might lead to new biomimetic systems for renal stem cell engineering.