Project description:: Sex determination triggers the differentiation of the bi-potential gonad into either an ovary or testis. In non-mammalian vertebrates, the presence or absence of oestrogen dictates gonad differ-entiation, while in mammals, this mechanism has been supplanted by the testis determining SRY gene. Exogenous oestrogen can override this genetic trigger to shift somatic cell fate in the gonad towards ovarian developmental pathways by limiting the bioavailability of the key testis factor SOX9 within somatic cells. Our previous work has implicated the MAPK pathway in mediating the rapid cellular response to oestrogen. We performed proteomic and phosphoproteomic anal-yses to investigate the precise mechanism through which oestrogen impacts these pathways to ac-tivate -catenin—a factor essential for ovarian development. We show that oestrogen can activate -catenin within 30 minutes, concomitant with the cytoplasmic retention of SOX9. This occurs through changes to the MAP3K1 cascade, suggesting this pathway is a mechanism through which oestrogen influences gonad somatic cell fate. We demonstrate that oestrogen can promote the shift from SOX9 pro-testis activity to -catenin pro-ovary activity through activation of MAP3K1. Our findings define a previously unknown mechanism through which oestrogen can promote a switch in gonad somatic cell fate and provided novel insights into the impacts of exogenous oestrogen exposure on the testis.
Project description:Single cell transcriptomic analyses are increasingly being employed to study human developmental processes in the gonad to advance our understanding of human gametogenesis. However, to date, these analyses have primarily focused on germ cells, while the somatic niche has been largely overlooked. Moreover, a comparative transcriptomic analysis of both female and male early gonad development on the single cell level is currently lacking. We performed single cell RNA-Seq on whole human fetal gonads from first and second trimester, both from male and female. We define gene expression profiles, which include novel marker genes, of major gonadal somatic cell types and validate them on the protein level. We identify the genetic signature of early human male rete cells, both in male and in female gonads. Overall, our study provides an in-depth molecular characterization of both male and female somatic cell types in early fetal gonads.
Project description:In this study, we generated a human inner ear atlas containing three stages of inner ear development. This atlas was used to evaluate the differentiation approach of human pluripotent stem cells in to complex inner ear tissue, known as inner ear organoids. The primary goal of this single-nucleus RNA-sequencing analysis was to capture the cell type diversity of the human inner ear at different stages of development. The secondary goal was to define the similarity of organoid-derived inner ear cell types with the atlas-derived human inner ear cell types and to determine the developmental stage of the organoid-derived inner ear cell types.
