Project description:Bone marrow mesenchymal lineage cells are a heterogeneous cell population involved in bone homeostasis and diseases such as osteoporosis. While it is long postulated that they originate from mesenchymal stem cells (MSCs), the true identity of MSCs and their in vivo bifurcated differentiation routes into osteoblasts and adipocytes remain poorly understood. Here, by employing large scale single cell transcriptome analysis, we computationally defined MSCs and delineated their bi-lineage differentiation paths in young, adult and aging mice. One identified subpopulation is a unique cell type that expresses adipocyte markers but contains no lipid droplets. As non-proliferative precursors for adipocytes, they exist abundantly as pericytes and stromal cells that form a ubiquitous 3D network inside the marrow cavity. Functionally they play critical roles in maintaining marrow vasculature and suppressing bone formation. Therefore, we name them marrow adipogenic lineage precursors (MALPs) and conclude that they are a new component of marrow adipose tissue.
Project description:This study provides gene expression profiles of bone marrow mesenchymal lineage cell and endothelial cell subsets from a CXCR4 gain-of- function mouse model of WHIM syndrome at the population level.
Project description:Radiation causes a collapse of bone marrow cells and elimination of microvasculature. Bone marrow has a limited regenerative ability and the mechanism governing such recovery is largely unknown. Mesenchymal lineage cells provide supportive microenvironment for hematopoiesis and angiogenesis in bone. We recently discovered a non-proliferative mesenchymal subpopulation, marrow adipogenic lineage precursors (MALPs), that express most adipogenic markers with no lipid accumulation. To investigate the acute radiation effects, we performed single cell RNA-sequencing (scRNA-seq) on bone marrow mesenchymal lineage cells at day 3 after focal radiation. Interestingly, computational analysis revealed that MALPs become highly proliferative and acquire myofibroblast features after radiation. Using an adipocyte-specific Adipoq-Cre to label MALPs in vivo, we found that radiation indeed rapidly and transiently expands MALPs. MALPs have a cell body with multiple cell processes that form a 3D network inside bone marrow. Shortly after radiation, MALPs lost most of cell processes, became more elongated, and highly expressed myofibroblast-related genes, coinciding with marrow vessel dilation and diminished bone marrow cellularity. Later when vessels and hematopoietic cells recovered, MALPs returned to the baseline number and a normal reticular shape. Ablation of MALPs completely blocked the recovery of bone marrow vasculature and cellularity, including hematopoietic stem and progenitors. MALPs highly express several hematopoietic and angiogenic factors. Depleting one of them, VEGFa, specifically in MALPs, delayed bone marrow recovery after radiation. Taken together, our research demonstrates a critical role of MALPs in mediating the marrow repair after radiation injury and sheds light on a new cellular target for treating marrow suppression after radiotherapy.
Project description:Bone marrow-derived mesenchymal stem cells (MSCs) differentiate into osteoblasts upon induction by signals present in their niche. As the global signaling cascades involved in the early phases of MSCs osteoblast (OB) differentiation are not well-defined, we employed quantitative mass spectrometry (SILAC based) to delineate changes in human MSCs proteome and phosphoproteome during the first 24 hours of their OB lineage commitment. The temporal profiles of 6,252 proteins and 15,059 phosphorylation sites suggested at least two distinct signaling waves: one peaking within 30 to 60 min after induction and a second upsurge after 24 hours
Project description:TGF-β regulates fetale bone marrow niche emergence. Abrogating TGF-β signaling in mesenchymal cells during development results in a marked expansion of adipocytes and CAR cells in the bone marrow, while osteoblasts are reduced. RNA expression data from Osx-Cre targeted mesenchymal stromal cells obtained from E16.5 mouse hindlimbs of transgenic mice lacking Tgfbr2 in mesenchymal stromal cells or littermate controls.
Project description:2D IDA protein quantitation of mesenchymal stem cells derived from bone
marrow across five donors. A total of 10 2D LC-MS runs were performed, using cells both not stimulated and following a 20 hour treatment with interferon gamma.
Project description:Conflicting reports exist on whether endothelial cells (ECs) serve as a source of bone marrow stromal cells (BMSCs). In studies concerning the endothelial-to-mesenchymal transition (EndoMT), ECs expressing mesenchymal markers, as well as BMSCs expressing endothelial markers, are typically considered intermediates of EndoMT. To understand the lineage relationship between ECs and BMSCs in postnatal mouse bone marrow, we performed single-cell RNA sequencing (scRNA-seq) on ECs and BMSCs obtained from 5-week-old wild-type C57BL/6J mice, and analyzed the potential intermediates of EndoMT. Subsequently, BMSC and EC lineage tracing models, flow cytometry, and immunostaining techniques were used to validate the findings from scRNA-seq analysis.
Project description:Adipose-derived and bone-marrow-derived mesenchymal stem cells were collected from 3 pigs and cultivated in vitro up to 3 passages. At passage 3 cells were cultured to 80% confluence and induced to differentiate in adipose and bone. Cell were harvested at 0 day of differentiation (dd) or pre-differentiation, at 2, 7, and 21dd for RNA extraction. The RNA was used for a large microarray analysis using a specific pig oligo-array with >10,000 annotated genes. The main aim of the microarray analysis was to directly compare the two transcriptomics adaptation of the two mesenchymal stem cells during osteogenic and adipogenic differentiation The mesenchymal stem cells were harvested at 0, 2, 7, and 21 day of differentiation (dd). A dye-swap reference design (reference = mixture of RNA from several porcine tissues) was used.
Project description:To investigate the alteration of bone marrow environment caused by Pinch loss, we performed single-cell RNA-sequencing on bone marrow cells, including hematopoietic cells and non-hematopietic stromal cells. As results indicated, we found both cell type proportion and transcriptomic signatures were dramatically altered by Pinch loss. We identified genes related to ossification, extracellular matrix organization, skeletal system development, and vasculature structure development were significantly differentially expressed between control group and dKO group in many mesenchymal stromal cells. Our results revealed Pinch loss disrupted homeostasis of bone marrow niche, monocytes in bone marrow were actively involved in inflammatory response, and functions of mesenchymal stromal cells was severely disrupted.