Generation of a model for human prostate development using patient derived induced pluripotent stem cells

Abstract

Research into highly prevalent prostate diseases is limited by lack of a relevant human model for prostate development and disease. The finding that stem cells can be generated from somatic cells, termed induced pluripotent stem cells (iPSCs), has revolutionised the field of human developmental and disease modelling. However, iPSCs retain an epigenetic signature from their parental tissue of origin which can result in a skewed differentiation potential. In this study, we have generated integration-free iPSCs from patient derived prostatic fibroblasts. These ProiPSCs show typical pluripotent stem cell characteristics including ESC-like morphology, expression of pluripotency markers and the ability to differentiate to cells from the three embryonic germ layers both in vitro, by formation of embryoid bodies, and in vivo, by teratoma formation. Using inductive rodent urogenital sinus mesenchyme (UGM), we have successfully generated prostatic tissue from the ProiPSCs using a tissue recombination approach. The generated tissue shows a normal spatial organisation with a basal and luminal layer characterised by expression of p63 and cytokeratins (CK) 8 and 18 respectively. Furthermore, the epithelial glands generated express the prostate markers androgen receptor (AR) and prostate specific antigen (PSA), confirming full functional differentiation. By harnessing the inductive nature of UGM, we subsequently developed a novel 3D co-culture system which allowed formation of prostatic organoids from both ProiPSCs and urinary tract derived iPSCs (UTiPSCs). The organoids were multi-layered with a basal layer expressing p63 and 34e12 and a luminal layer which expressed CK8/18. Prostatic differentiation was confirmed by positive staining for AR and PSA. In conclusion, we have demonstrated successful reprogramming of human prostate fibroblasts into iPSCs and subsequent differentiation of these cells to prostate epithelial cells in vitro and in vivo. This model provides a novel opportunity for studying prostate development as well as a potential system for disease modelling and drug testing.