Project description:Failures in germline development are a major cause of male infertility. However, the search for novel treatments is hampered by the lack of experimental systems that faithfully recapitulate human spermatogenesis. Here, we have developed a system to differentiate human induced pluripotent stem cells (iPSCs) into primordial germ cell-like cells that self-organize within xenogeneic reconstituted testes (xrTestes) generated from mouse fetal testicular cells. Subsequent transplant of xrTestes into immunodeficient mice resulted in efficient generation of undifferentiated and differentiated spermatogonia as well as preleptotene spermatocytes with striking similarities to their in vivo counterparts. As the fertilization competency of human iPSC-generated germ cells cannot be evaluated due to ethical constraints, we utilized a similar strategy to differentiate rhesus iPSCs through all fetal germ cell stages into spermatogonia-like cells. Together, these newly identified models of human gametogenesis will allow further mechanistic assessment of both germ cell development and genetic causes of infertility.
Project description:Pluripotent stem cells, which are capable to generate any cell type of the human body, such as human embryonic stem cells (hESC) or human induced pluripotent stem cells (hiPS) are a very promising source of cells for regenerative medicine. However, the genesis, the in vitro amplification and the differentiation of these cells still need improvement before clinical use. This study aimed to improve our knowledge on these critical steps in pluripotent stem cell generation. We derived new hESC lines, generated hiPS and compared these cell types with human foreskin fibroblasts and partially reprogrammed fibroblasts. We included in the overall study hESC, hiPS, human foreskin fibroblasts and partially reprogrammed fibroblasts. Here, hESC lines derived from embryos were hybridized on U133 Plus 2.0 GeneChips (Affymetrix). All samples were normalized using the MAS5 (GCOS 1.2) algorithm, using the default analysis settings and global scaling as normalization method, with a trimmed mean target intensity value (TGT) of each array arbitrarily set to 100. Human pluripotent stem cells were compared with somatic samples and partially reprogrammed cells.
Project description:Pluripotent stem cells, which are capable to generate any cell type of the human body, such as human embryonic stem cells (hESC) or human induced pluripotent stem cells (hiPS) are a very promising source of cells for regenerative medicine. However, the genesis, the in vitro amplification and the differentiation of these cells still need improvement before clinical use. This study aimed to improve our knowledge on these critical steps in pluripotent stem cell generation. We derived new hESC lines, generated hiPS and compared these cell types with human foreskin fibroblasts and partially reprogrammed fibroblasts.
Project description:Human primordial germ cells and mouse neonatal and adult germline stem cells are pluripotent and derive embryonic stem cell properties. Here we report the successful establishment of stable pluripotent human adult germline stem cells (haGSCs) derived from spermatogonial cells of adult human testis. Cellular and molecular characterization of haGSCs revealed many similarities to human embryonic stem (hES) cells and haGSCs produced teratomas after subcutaneous transplantation into immunodeficient mice. The haGSCs differentiated into various types of somatic cells of all three germ layers when grown under conditions used to induce the differentiation of hES cells. We conclude that the generation of haGSCs from testicular biopsies may provide simple and non-controversial access to individual cell-based therapy without the ethical and immunological problems associated with hES cells. Keywords: pluripotent stem cells characterisation