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 stromal cells (BMSCs) were isolated from the femora and tibiae of irtTA-GBD*-TAg transgenic mice. Using cellular cloning we established skeletal progenitors with unipotent osteogenic and adipogenic properties. Previous RNA-seq analysis of more progenitor types revealed differential expression in members of the Interferon-gamma (IFNγ) signaling pathway. Treatment of adipogenic progenitors with IFNγ inhibited adipogenesis and promoted osteogenesis. RNA-seq analysis of osteogenic, adipogenic and IFNγ treated adipogenic clones revealed factors controlling the osteogenic versus adipogenic commitment of bone marrow skeletal progenitors.
Project description:In bone marrow, mesenchymal stromal cells (BMSCs), the precursors of adipocytes and osteoblasts, are exposed to a plethora of stimuli that determine the balance between adipogenesis and osteogenesis which in turn are competing and reciprocal. The differentiation of BMSCs, in fact, is a two-step process, lineage commitment (from MSCs to lineage-specific pro-genitors) and maturation (from progenitors to specific cell types). Adipogenesis is a finely tuned multi-step process requiring the sequential activation of numerous transcription factors driving the typical physiological and morphological changes observed in the progenitor cells, i.e., cell cycle arrest, metabolic reprogramming, and lipid accumulation. Among the small non-coding RNAs, microRNAs represent an additional mechanism for controlling adipogenic gene expression. Given their unique ability to simultaneously regulate multiple protein targets and processes, it has been suggested that microRNAs may play a leading role in BMSC differentiation. Here, we evaluated miRNAs differentially regulated during human BMSC adipogenic differentiation in vitro.
Project description:A set of key developmental genes is essential for skeletal growth from multipotent progenitor cells at weaning. Polycomb group proteins, which regulate such genes contributes to the cell lineage commitment and subsequent differentiation via epigenetic chromatin modification and remodeling. However, it is unclear which cell lineage and gene sets are targeted by polycomb proteins during skeletal growth. We now report that mice deficient in a polycomb group gene Cbx2 (cterm/cterm) exhibited skeletal hypoplasia in the tibia, femur, and cranium. Long bone cavities in these mice contained fewer multipotent mesenchymal stromal cells. RNA-sequencing of bone marrow cells showed downregulation and upregulation of osteoblastic and adipogenic genes, respectively. Furthermore, the expression levels of genes specifically expressed in B-cell precursors were decreased. Forced expression of Cbx2 in Cbx2 (cterm/cterm) bone marrow stromal cell recovered fibroblastic colony formation and suppressed adipogenic differentiation. Collectively, our results suggest that Cbx2 controls the maintenance and adipogenic differentiation of mesenchymal stromal cells in the bone marrow.
Project description:Pericryptal myofibroblasts in the colon and rectum play an important role in regulating the normal colorectal stem cell niche and facilitating tumour progression. Myofibroblasts have previously mostly been distinguished from normal fibroblasts only by the expression of α smooth muscle actin (αSMA). We now identify AOC3, a surface monoamine oxidase, as a new marker of myofibroblasts by showing that it is the target protein of the myofibroblast reacting monoclonal antibody (mAb), PR2D3. The normal and tumour tissue distribution and the cell line reactivity of AOC3 match that expected for myofibroblasts. We have shown that the surface expression of AOC3 is sensitive to digestion by trypsin and collagenase and that anti-AOC3 antibodies can be used for FACS sorting of myofibroblasts obtained by non-enzymatic procedures. Whole genome microarray mRNA expression profiles of myofibroblasts and skin fibroblasts revealed four additional genes that are significantly expressed differentially between these two cell types; NKX2-3 and LRRC17 are expressed in myofibroblasts and SHOX2 and TBX5 in skin fibroblasts. Transforming Growth Factor β (TGFβ) substantially down-regulated AOC3 expression in myofibroblasts but not in skin fibroblasts, in which it dramatically increased the expression of αSMA. A knockdown of NKX2-3 in myofibroblasts caused a decrease of myofibroblast-related gene expression and an increased expression of the fibroblast associated gene, SHOX2, suggesting that NKX2-3 is a key mediator for maintaining myofibroblast characteristics. Our results show that colorectal myofibroblasts, as defined by the expression of AOC3, NKX2-3 and other markers, are a distinctly different cell type from TGFβ activated fibroblasts. colorectal myofibroblast specific markers and expression profiles were sought by comparing four primary myofibroblast cultures to a panel of four dermal and foreskin fibroblast cell lines Four primary myofibroblast cultures established from adult human colon compared to four skin fibroblast cell lines to identify intestinal myofibroblast specific markers
Project description:Skin is the largest organ in the body and comprises several types of cells. The intercellular plasticity of keratinocytes, fibroblasts, and skin adipocytes contributes to wound healing and dermal adipogenesis. Although keratinocyte activates dermal adipose tissue (dWAT) differentiation upon hair follicular cycle, regulating dWAT hyperplasia through keratinocyte reprogramming is still unknown. We used the CRISPR/Cas9 base editor to induce single nucleotide polymorphisms in Forkhead-box N1 (Foxn1) and identified the p.L19M variant that induced the formation of a thicker dWAT regardless of hair follicular cycle or wound healing. Foxn1 p.L19M activates Wnt5β through transcriptional activity. Wnt5β signaling induces the conversion of dWAT dermal fibroblasts into adipose precursor cells (APCs) and promotes APC adipocyte differentiation through keratinocyte epithelial-mesenchymal transition (EMT) and adipogenic signaling. Wnt5β is involved in the entire process of dWAT hyperplasia through APC supply and adipogenic signaling as a single factor. Foxn1 p.L19M and Wnt5β are expressed in keratinocytes, and a keratinocyte-derived adipogenic signal is critical for dermal adipogenesis. In addition, transient expression of Foxn1 p.L19M or Wnt5β using adeno-associated virus reproduced dermal adipocyte hyperplasia in mice. Considering the increasing importance of dWAT in functions such as the immune response, wound healing, hair follicle growth, and temperature control, this finding has potential applications in skin regeneration
Project description:While the accumulation of bone marrow adipose tissue has been positively associated with aging and high fat diet, the physiological consequences are mostly unknown. It is well established that osteogenic and adipogenic progenitors share a common developmental origin.Unfavorable microenvironmental changes may bias these cell populations towards an adipogenic fate, which in turn could negatively influence bone homeostasis. Our previously collected data from mice reveal a high plasticity of the mesenchymal osteo-adipogenic stem cell population. Therefore, we now wish to perform by RNA-seq in defined cell population with varying adipogenic commitment within this heterogeneous stem cell pool.This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/
Project description:Bone marrow mesenchymal stromal cells (MSCs) constitute one of the important components of the hematopoietic microenvironmental niche. There is in vitro evidence that marrow MSCs are able to support leukemia progenitor cell proliferation and survival and provide resistance to cytotoxic therapies. How MSCs from leukemia marrow differ from normal counterparts and how they are influenced by the presence of leukemia stem, and progenitor cells are still incompletely understood. In this work, we compared normal donor (ND) and acute myelogenous leukemia (AML) derived MSCs and found that AML-MSCs had increased adipogenic potential with improved ability to support survival of leukemia progenitor cells. To identify underlying changes, RNA-Seq analysis was performed. Gene ontology and pathway analysis revealed adipogenesis to be among the set of altered biological pathways dysregulated in AML-MSCs as compared to ND-MSCs. Expression of both SOX9 and EGR2 was decreased in AML-MSCs as compared to ND-MSCs. Increasing expression of SOX9 decreased adipogenic potential of AML-MSCs and decreased their ability to support AML progenitor cells. These findings suggest that AML-MSCs possess adipogenic potential which may enhance support of leukemia progenitor cells.
Project description:Expression profiling of mouse bone marrow skeletal progenitors with osteogenic and adipogenic potential and adipogenic progenitors treated with IFNγ.