Project description:Mapping the transcriptional landscape of human embryonic skeletogenesis at single-cell resolution during limb bud and primary ossification center (POC) formation. We found significant heterogeneity of stromal cells within the limb bud mesenchyme that specified proximal-distal and anterior-posterior patterning. Embryonic skeletal stem and progenitor cells first appeared during POC formation, which were highly enriched by CADM1 expression and could differentiate into osteoblasts, chondrocytes and periosteal mesenchymal stromal cells.
2021-01-24 | GSE143753 | GEO
Project description:Rhinolophus sinicus limb embryonic development single cell transcriptome
Project description:Although the landscape of epigenomic and transcriptomic regulation during human pre-implantation development has been depicted by applying single-cell sequencing, the investigation of embryonic proteome is almost unrevealed due to the insufficient input quantity from precious human embryonic samples for traditional mass spectrometry (MS). With applying the state-of-the-art ultrahigh sensitivity mass spectrometry technology and nanoliter-scale oil-air-droplet (OAD) chip, we were able to identify more than three thousand proteins in a single oocytes during human pre-implantation development. Hundreds of stage-specific proteins with significant expressional changes were classified. Many that involve important functions, such as paternal genome reprogramming or DNA methylation, were firstly identified in human embryo studies. We discovered a two peaks of “zygotic proteome activation” (ZPA) at 2-cell and morula stages, in which proteins are mainly associated with epigenetic reprogramming. Our study, for the first time, delineates a comprehensive stage-specific proteome landscape at a single-cell level. It is as well a large step of enriching the panorama of functional genomics across human pre-implantation embryo development.
Project description:Human limbs emerge during the fourth post-conception week as mesenchymal buds, which develop into fully formed limbs over the subsequent months. This process is orchestrated by numerous temporally and spatially restricted gene expression programmes, making congenital alterations in phenotype common. Decades of work with model organisms have defined the fundamental mechanisms underlying vertebrate limb development, but an in-depth characterization of this process in humans has yet to be performed. Here we detail human embryonic limb development across space and time using single-cell and spatial transcriptomics. We demonstrate extensive diversification of cells from a few multipotent progenitors to myriad differentiated cell states, including several novel cell populations. We uncover two waves of human muscle development, each characterized by different cell states regulated by separate gene expression programmes, and identify musculin (MSC) as a key transcriptional repressor maintaining muscle stem cell identity. Through assembly of multiple anatomically continuous spatial transcriptomic samples using VisiumStitcher, we map cells across a sagittal section of a whole fetal hindlimb. We reveal a clear anatomical segregation between genes linked to brachydactyly and polysyndactyly, and uncover transcriptionally and spatially distinct populations of the mesenchyme in the autopod. Finally, we perform single-cell RNA sequencing on mouse embryonic limbs to facilitate cross-species developmental comparison, finding substantial homology between the two species.
Project description:Understanding how uniquely human genetic changes altered developmental processes is essential to understanding human evolution. We investigated the role of the Human Accelerated Region HACNS1 in human limb evolution by directly interrogating its biological functions in a humanized mouse model. Using genome-wide epigenetic profiling, we found that HACNS1 maintains its human-specific transcriptional enhancer activity compared to its chimpanzee ortholog in the mouse embryonic limb, and that it alters promoter activity of the transcription factor gene Gbx2. Using single-cell transcriptional profiling, we demonstrate that Gbx2 is upregulated in humanized limb bud chondrogenic mesenchyme, providing insight into the developmental processes altered due to human-specific alterations in enhancer activity. Our findings establish that HACNS1 directs changes in the level and distribution of gene expression during development, and illustrate how humanized mouse models provide insight into regulatory pathways altered in human evolution.
Project description:Mouse embryonic stem cells were used to generate cell types of limb development and characterized using single-cell mRNA-sequencing.
