Single cell RNA sequence discover the musculoskeletal tissue cell atlas during limb development
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ABSTRACT: By using single cell RNA-seq,We dissect the cellular heterogeneity and transcriptome profiles during limb development, and reveal the characteristic features of limb development and musculoskeletal stem/progenitor cell populations involved in limb lineage development. Our study therefore systematically decoded molecular markers and cellular program of limb development that would shed lights on limb developmental biology.
Project description:Detailed information about stage-specific changes in gene expression is crucial for understanding the gene regulatory networks underlying development and the various signal transduction pathways contributing to morphogenesis. Here, we describe the global gene expression dynamics during early murine limb development, when cartilage, tendons, muscle, joints, vasculature, and nerves are specified and the musculoskeletal system of the limbs is established. We used whole-genome microarrays to identify genes with differential expression at 5 stages of limb development (E9.5 to 13.5), during fore-limb and hind-limb patterning. We found that the onset of limb formation is characterized by an up-regulation of transcription factors, which is followed by a massive activation of genes during E10.5 and E11.5 which tampers off at later time points. Among 3520 genes identified as significantly up-regulated in the limb, we find ~30% to be novel, dramatically expanding the repertoire of candidate genes likely to function in the limb. Hierarchical and stage-specific clustering identified expression profiles that correlate with functional programs during limb development and are likely to provide new insights into specific tissue patterning processes. Here we provide for the first time, a comprehensve analysis of developmentally regulated genes during murine limb development, and provide some novel insights into the expression dynamics governing limb morphogenesis. Fifty- one arrays were analyzed, consisting of whole fore-limb and hind-limb bud RNA (experimental) and whole embryo RNA (reference) samples from E9.5 to E13.5 DPC mouse (FVB strain). Embryos were not pooled to generate samples. Each time point has 3 to 5 biological replicates for limb bud samples, duplicates for whole embryos. Comparisons were made between limb bud samples and whole embryo at the same stage, fore-limb samples of different stages, hind-limb samples of different stages, and fore-limb samples compared to hind-limb samples at the same or the next stage.
Project description:26 limb-girdle muscular dystrophy patients from Latvia and 34 patients from Lithuania with clinical symptoms of limb-girdle muscular dystrophies, along with 204 healthy unrelated controls were genotyped for 96 most frequent known limb-girdle muscular dystrophies causing mutations for the region, using VeraCode GoldenGate system. More information can be found in article Robust genotyping tool for autosomal recessive type of limb-girdle muscular dystrophies in BMC Musculoskeletal Disorders by I. Inashkina et al.
Project description:Detailed information about stage-specific changes in gene expression is crucial for understanding the gene regulatory networks underlying development and the various signal transduction pathways contributing to morphogenesis. Here, we describe the global gene expression dynamics during early murine limb development, when cartilage, tendons, muscle, joints, vasculature, and nerves are specified and the musculoskeletal system of the limbs is established. We used whole-genome microarrays to identify genes with differential expression at 5 stages of limb development (E9.5 to 13.5), during fore-limb and hind-limb patterning. We found that the onset of limb formation is characterized by an up-regulation of transcription factors, which is followed by a massive activation of genes during E10.5 and E11.5 which tampers off at later time points. Among 3520 genes identified as significantly up-regulated in the limb, we find ~30% to be novel, dramatically expanding the repertoire of candidate genes likely to function in the limb. Hierarchical and stage-specific clustering identified expression profiles that correlate with functional programs during limb development and are likely to provide new insights into specific tissue patterning processes. Here we provide for the first time, a comprehensve analysis of developmentally regulated genes during murine limb development, and provide some novel insights into the expression dynamics governing limb morphogenesis.
Project description:The coordinated spatial and temporal regulation of gene expression in the murine hindlimb determines the identity of mesenchymal progenitors and the development of diversity of musculoskeletal tissues they form. Hindlimb development has historically been studied with lineage tracing of individual genes selected a priori, or at the bulk tissue level, which does not allow for the determination of single cell transcriptional programs yielding mature cell types and tissues. To identify the cellular trajectories of lineage specification during limb bud development, we used single cell mRNA sequencing (scRNA-seq) to profile the developing murine hindlimb between embryonic days (E)11.5-E18.5. We found cell type heterogeneity at all time points, and the expected cell types that form the mouse hindlimb. In addition, we used RNA fluorescence in situ hybridization (FISH) to examine the spatial locations of cell types and cell trajectories to understand the ancestral continuum of cell maturation. This data provides a resource for the transcriptional program of hindlimb development that will support future studies of musculoskeletal development and generate hypotheses for tissue regeneration.
Project description:m6A regulates virtually every step in RNA metabolism. However, its toles in limb development remains largely unknown. To understand the roles, we created a limb bud-specific conditional knockout (cKO) mice and control heterozygous (cHet) mice of the Mettl14 gene, which encodes an essential subunit in the m6A methyltransferase complex METTL3/METTL14. We harvested limb buds from the mice on E12.5 and applied the proteins to quantitative mass spectrometry to understand how the depletion of Mettl14 affected the proteomes.
Project description:Although connective tissues play critical roles in development, our understanding of connective tissue fibroblast developmental programs lag behind that of other components of the musculoskeletal system mainly because fibroblasts are highly heterogeneous and poorly characterized. Combining single-cell RNA-sequencing-based strategies, including trajectory inference, and in situ hybridization analyses, we address the diversity of connective tissue fibroblasts and their developmental trajectories during chicken limb foetal development. We show that fibroblasts switch from a positional information to a lineage diversification program during their development. Muscle connective tissue and tendon contain several fibroblast populations that emerge asynchronously. In fine, these populations map to distinct layers, prefiguring the adult fibroblast layers. Populations that are close in transcriptional identity are found in neighboring layers. Altogether, we propose that the limb connective tissue is organised in a continuum of promiscuous fibroblasts identities, allowing for the robust and efficient connection of highly different tissues such as muscle, bone and skin.
Project description:An approximately 60% of chronic myeloid leukemia (CML) patients who achieved a deep molecular response for more than 2 years maintained a major molecular response after discontinuation of imatinib. These findings indicate the possibility that a portion of CML patients treated with Tyrosine kinase inhibitors (TKIs) could discontinue TKI therapy, although long-term prognosis and/or adverse events after TKIs cessation remain unclear. Recent reports showed that transient musculoskeletal pain occurs in approximately 30% of CML patients after stopping imatinib. To ascertain the factors underlying musculoskeletal events after TKI cessation, we investigated exosomal miRNA in five CML patients who did not experience musculoskeletal events and five patients with musculoskeletal pain after stopping TKIs.
Project description:Human bone-marrow-derived mesenchymal stem cells from young and old donors and tenogenic, chondrogenic and osteogenic constructs derived from these were subject to RNASeq and miRNASeq. We wished to identify common pathways of musculoskeletal ageing.
Project description:Human bone-marrow-derived mesenchymal stem cells from young and old donors and tenogenic, chondrogenic and osteogenic constructs derived from these were subject to RNASeq and miRNASeq. We wished to identify common pathways of musculoskeletal ageing.