Development of human primordial germ cells towards the onset of sperm and egg differentiation in a novel model culture system

ended

Human primordial germ cells (hPGCs), the precursors of sperm and eggs, originate in early pre-gastrulation post-implantation embryos (~wk2). Thereafter, hPGCs undergo wide epigenetic reprogramming during their migration to the primitive gonads (~wk3–7). While technical and ethical constraints preclude direct studies on early human embryos, recent development of 2D models using human pluripotent stem cells (hPSC), which simulate early post-implantation development, have been used to investigate the specification of hPGC-like cells (PGCLCs) equivalent to wk2 hPGCs. These models however cannot support extended maturation of hPGCLCs beyond this early stage. Here, we propose a novel 3D in vitro system to advance development of hPGCLCs up to the onset of gametogenesis, extending our knowledge of the key events of early human germline development. This project will benefit from the cell culture capabilities of the three-layer gradient system (3-LGS), a 3D cell culture method that I invented during my PhD, combined with the expertise of Prof. Surani’s lab in generating hPGCLCs from hPSCs. The 3-LGS will be used to create gonadal organoids from human fetal primary cells, which we call “germinoids”, in order to support further development of hPGCLCs beyond the in vivo equivalent 2-wk stage. During this innovative project, we intend to achieve our objectives to create firstly, the novel co-culture germinoid conditions, and secondly to use the model to advance hPGCLCs differentiation. The generation and characterization of germinoids will be conducted in a collaborative team of experienced scientists and students, under renowned supervision and within a supportive and available work environment and infrastructure. This project will extend my expertise and contribute to the host’s work on early human germ cell development. The outcome will be a breakthrough in the field of human germ cell biology, which will contribute to my ambition to progress my independent research career.