Human embryonic stem cells differentiate into functional renal proximal tubular–like cells

Abstract

Renal cells are used in basic research, disease models, tissue engineering, drug screening, and in vitro toxicology. In order to provide a reliable source of human renal cells, we developed a protocol for the differentiation of human embryonic stem cells into renal epithelial cells. The differentiated stem cells expressed markers characteristic of renal proximal tubular cells and their precursors, whereas markers of other renal cell types were not expressed or expressed at low levels. Marker expression patterns of these differentiated stem cells and in vitro cultivated primary human renal proximal tubular cells were comparable. The differentiated stem cells showed morphological and functional characteristics of renal proximal tubular cells, and generated tubular structures in vitro and in vivo. In addition, the differentiated stem cells contributed in organ cultures for the formation of simple epithelia in the kidney cortex. Bioreactor experiments showed that these cells retained their functional characteristics under conditions as applied in bioartificial kidneys. Thus, our results show that human embryonic stem cells can differentiate into renal proximal tubular-like cells. Our approach would provide a source for human renal proximal tubular cells that are not affected by problems associated with immortalized cell lines or primary cells.

Rapid and Efficient Differentiation of Human Pluripotent Stem Cells into Intermediate Mesoderm That Forms Tubules Expressing Kidney Proximal Tubular Markers

“…Although the differentiation of hPSCs into cells of the cardiac, hepatic, pancreatic, and neuronal lineages has been widely reported, relatively few previous studies have attempted to derive cells of the kidney lineage from hPSCs. [16][17][18][19] An alternative to directed differentiation was recently demonstrated by means of direct reprogramming of immortalized human kidney cells into nephron progenitor-like cells; however, the efficiency of integration into kidney explant cultures was reportedly low. 63 Mae and colleagues demonstrated induction of an intermediate mesoderm population using a stepwise combination of CHIR, activin, and BMP7 signaling in engineered OSR1-GFP hiPSC cell lines, achieving efficiencies of .90% of OSR1-GFP + cells after 11-18 days of differentiation.…”

“…63 These polarized tubular structures could reproducibly form in monolayer culture, in contrast to previous reports in which tubular structures derived from differentiated hPSCs cells could form only with three-dimensional culture in vitro or after incorporation into mouse metanephric kidneys ex vivo. 17,18 Furthermore, using the combination of FGF9 and activin, we could specifically direct the differentiation of PAX2 + LHX1…”

“…[16][17][18][19] These previous reports have produced cells that share characteristics expected of human kidney progenitor or epithelial cells, although the identities of these differentiated cells have yet to be conclusively verified. In addition, the efficiencies of these protocols for generating cells of the renal lineage are low, necessitating the use of cell sorting to enrich populations of cells using markers that are not entirely specific to the kidney.…”

“…For example, OSR1, used as a marker by Mae and colleagues to label cells of the intermediate mesoderm, 17 is also expressed in lateral plate mesoderm, 20 which gives rise during embryonic development to the adult heart, hematopoietic system, and vasculature. Narayanan and colleagues isolated populations of AQP1 + proximal tubular-like cells, 18 but this marker is expressed not only in the kidney but also broadly in the gastrointestinal system, lungs, and blood cells. 21 In both instances, the sorted cells were heterogeneous and included a small percentage of cells that exhibited properties and behaviors of cells of the kidney lineage.…”

Current status of bioartificial kidney

“…Besides that, government-related organization such as FDA or EMA should approve human clinical trial testing. Recently, methodology about the differentiation of human embryonic stem cells into functional renal tubular cells has been described [4], and it will be helpful to accelerate the development of bioartificial kidney.…”