Project description:Here, we used single-cell RNA sequencing (scRNA-seq) to provide a high-resolution cellular taxonomy of freshly isolated primary human osteoblasts. Based on the gene expression patterns and cell lineage reconstruction, we identified three distinct clusters including preosteoblasts, mature osteoblasts, and an undetermined rare osteoblast subpopulation. Trajectory inference analysis suggested that the undetermined cluster may include osteoblast precursor cells which regulate the osteoblastogenesis process by giving rise to pre and mature osteoblasts. Investigation of the biological processes and signaling pathways enriched in each subpopulation revealed that in addition to bone formation, pre and undetermined osteoblasts may regulate both angiogenesis and hemopoiesis.
Project description:We utilized RNA sequencing to provide the gene expression profile of mesenchymal stem cells (MSCs) derived osteoblasts in different differentiation stages as well as the gene alteration profile of H9 MSCs-derived osteoblasts following different gene regulation treatments, including SDC1 overexpression, knockout of CEBPD, knockout of IL1R1, and knockdown of CORIN. The commitment of stem cells to an osteoblastic lineage is a complex and tightly regulated process, involving coordination between extrinsic signals and intrinsic transcriptional machinery. While many rodent osteoblast studies abound, human osteoblastic signaling networks are not as well-researched due to limitations in cell sources and existing models. Here, we generated human pluripotent stem cell (hPSC)-derived osteoblasts and used this modeling platform to identify functional osteoblastic surface receptors and their downstream transcriptional networks involved in human osteogenesis. We systematically dissected osteoblastic gene expression patterns and identified critical clusters associated with osteogenesis. The osteoblast surface receptor signature study revealed enriched CORIN expression in osteoblasts and enriched SDC1 expression in MSCs. In vitro calcified staining and 3D biomimetic GelMA/microCT (μCT) studies demonstrated that depletion of CORIN as well as ectopic expression of SDC1 significantly impaired osteogenesis. Transcriptome analyses revealed that dysregulation of CORIN or SDC1 alters biological processes and pathways mainly involved in bone formation associated signaling including TGFβ regulating extracellular matrix and Wnt signaling. Genome-wide ChIP enrichment analysis further indicated that CEBPD is a downstream transcription factor involved in CORIN and SDC1-modulated osteogenesis. CEBPD ChIP-seq and RNA-seq validated its role in controlling extracellular matrix organization, bone mineralization, and TGFβ, BMP, and Wnt signaling. Depletion of CEBPD led to impairment of osteoblastic differentiation. Differential expression analysis of single-cell transcriptomes revealed enriched expression of CEBPD and its transcriptional targets during the different stages of osteoblast differentiation. In summary, our findings elucidated the vital signaling in osteoblast lineage commitment.
Project description:The overall purpose of this study is to describe the cellular composition of the human colon and its gene expression using scRNAseq and scATACseq methods. This will potentially provide is with a detailed map of the colon aiding our understanding of how diseases of the colon develop as well as the colons influence on systemic diseases such as type II diabetes.