Large Granular Lymphocyte Leukemia Mesenchymal Stem Cells
Ontology highlight
ABSTRACT: The bone marrow microenvironment in Large Granular Lymphocyte Leukemia (LGLL) patients has been unexplored for it’s role in the development of cytopenias, which lead to complications resulting in the most prominent causes of morbidity and mortality. We used microarrays on primary mesenchymal stem cell (MSC) cultures isolated from bone marrow aspirates from LGLL patients to identify genetic programs that may lead to the observed profibrotic and extrinsically senescent phenotype. Isolated primary MSC cultures were maintained under reduced oxygen conditions (2%). All cultures displayed trilineage pluripotency (adipogenesis, osteogenesis, and chondrogenesis). For comparison, normal MSC cultures in early passage (p2-3; same number of population doublings as the LGLL MSCs) and later passage (p7-9; same time spent in culture as the LGLL MSCs) are included.
Project description:The bone marrow microenvironment in Large Granular Lymphocyte Leukemia (LGLL) patients has been unexplored for it’s role in the development of cytopenias, which lead to complications resulting in the most prominent causes of morbidity and mortality. We used microarrays on primary mesenchymal stem cell (MSC) cultures isolated from bone marrow aspirates from LGLL patients to identify genetic programs that may lead to the observed profibrotic and extrinsically senescent phenotype.
Project description:Bone marrow mesenchymal stromal cells (MSCs) that express high levels of stem cell factor (SCF) and CXC chemokine ligand 12 (CXCL12) are one crucial component of the hematopoietic stem cell (HSC) niche. While the secreted factors produced by MSCs to support HSCs have been well described, little is known regarding the transcriptional regulators controlling the cell fate of MSCs and thus indirectly maintaining HSCs. Bmi1 is a polycomb group protein that regulates HSCs both cell intrinsically and extrinsically, but it is unknown in which cell type and how Bmi1 functions to maintain HSCs extrinsically. Here we show that Bmi1 maintains HSCs by preventing adipogenic differentiation of MSCs. Bmi1 is highly expressed in MSCs but becomes downregulated upon adipogenic differentiation and during aging. Deleting Bmi1 from MSCs increased marrow adipocytes, induced HSC quiescence and depletion, and impaired hematopoiesis. We found that Bmi1 repressed multiple developmental programs in MSCs by safeguarding the repressive epigenetic marks histone H2A ubiquitylation and H3 lysine 27 trimethylation. We identified a novel adipogenic program governed by Pax3, which Bmi1 repressed in MSCs. Our results establish Bmi1 as a critical regulator of MSC cell fate that suppresses marrow adipogenesis to create a supportive niche for HSCs.
Project description:Bone marrow mesenchymal stromal cells (MSCs) that express high levels of stem cell factor (SCF) and CXC chemokine ligand 12 (CXCL12) are one crucial component of the hematopoietic stem cell (HSC) niche. While the secreted factors produced by MSCs to support HSCs have been well described, little is known regarding the transcriptional regulators controlling the cell fate of MSCs and thus indirectly maintaining HSCs. Bmi1 is a polycomb group protein that regulates HSCs both cell intrinsically and extrinsically, but it is unknown in which cell type and how Bmi1 functions to maintain HSCs extrinsically. Here we show that Bmi1 maintains HSCs by preventing adipogenic differentiation of MSCs. Bmi1 is highly expressed in MSCs but becomes downregulated upon adipogenic differentiation and during aging. Deleting Bmi1 from MSCs increased marrow adipocytes, induced HSC quiescence and depletion, and impaired hematopoiesis. We found that Bmi1 repressed multiple developmental programs in MSCs by safeguarding the repressive epigenetic marks histone H2A ubiquitylation and H3 lysine 27 trimethylation. We identified a novel adipogenic program governed by Pax3, which Bmi1 repressed in MSCs. Our results establish Bmi1 as a critical regulator of MSC cell fate that suppresses marrow adipogenesis to create a supportive niche for HSCs.
Project description:Multipotent stromal cells (MSCs) are known for their distinctive ability to differentiate into different cell lineages such as adipocytes, chondrocytes and osteocytes. They can be isolated from numerous tissue sources including bone marrow, adipose tissue, skeletal muscle and others. Because of their differentiation potential and their secretion of growth factors, MSCs are believed to have an inherent quality of regeneration and immune suppression, which are considered advantageous in treating multiple disorders such as graft-versus-host disease. Since the number of MSCs derived from a tissue source is low, cellular expansion is necessary to obtain sufficient numbers for a desired cell therapy. However, after several rounds of passaging, our previous results have shown that MSCs exhibit reduced capacity for proliferation and differentiation. In this study, gene markers of MSC proliferation were identified and evaluated for their ability to predict the cell population proliferative quality. Microarray data of human bone marrow-derived MSCs were correlated with two proliferation assays. A collection of 24 genes were observed to significantly correlate with both proliferation assays (|r| > 0.70) for 8 MSC donors at multiple passages. These 24 identified genes were then confirmed using an additional set of MSCs from 8 new donors using RT-qPCR. The proliferative potential of the second set of MSCs was measured for each donor/passage by three proliferation assays for confluency fraction, fraction of EdU+ cells and population doubling time. The second set of MSCs exhibited a greater proliferative potential at passage 4 in comparison to passage 8, which was distinguishable by 15 genes; however, only 7 of the genes (BIRC5, CCNA2, CDC20, CDK1, PBK, PLK1, SPC25) demonstrated significant correlation (FDR: q < 0.05 and |r| > 0.62) with MSC proliferation regardless of passage. These 7 genes and the proliferative capacity of different non-MSC cell lines were assessed for comparison. Our analyses revealed that correlation between gene expression and proliferation was consistently reduced with the introduction of non-MSC cell lines; therefore this set of 7 genes may be more strongly associated with MSC proliferative quality. These correlative methods may be further used to identify additional markers that exhibit strong correlation with a particular MSC quality such as differentiation or immune suppression potential. Our results pave the way toward the identification of specific gene markers that could rapidly determine the quality of an MSC population for a particular cellular therapy in lieu of an extended in vitro or in vivo assay.
Project description:Multipotent stromal cells (MSCs) are known for their distinctive ability to differentiate into different cell lineages such as adipocytes, chondrocytes and osteocytes. They can be isolated from numerous tissue sources including bone marrow, adipose tissue, skeletal muscle and others. Because of their differentiation potential and their secretion of growth factors, MSCs are believed to have an inherent quality of regeneration and immune suppression, which are considered advantageous in treating multiple disorders such as graft-versus-host disease. Since the number of MSCs derived from a tissue source is low, cellular expansion is necessary to obtain sufficient numbers for a desired cell therapy. However, after several rounds of passaging, our previous results have shown that MSCs exhibit reduced capacity for proliferation and differentiation. In this study, gene markers of MSC proliferation were identified and evaluated for their ability to predict the cell population proliferative quality. Microarray data of human bone marrow-derived MSCs were correlated with two proliferation assays. A collection of 24 genes were observed to significantly correlate with both proliferation assays (|r| > 0.70) for 8 MSC donors at multiple passages. These 24 identified genes were then confirmed using an additional set of MSCs from 8 new donors using RT-qPCR. The proliferative potential of the second set of MSCs was measured for each donor/passage by three proliferation assays for confluency fraction, fraction of EdU+ cells and population doubling time. The second set of MSCs exhibited a greater proliferative potential at passage 4 in comparison to passage 8, which was distinguishable by 15 genes; however, only 7 of the genes (BIRC5, CCNA2, CDC20, CDK1, PBK, PLK1, SPC25) demonstrated significant correlation (FDR: q < 0.05 and |r| > 0.62) with MSC proliferation regardless of passage. These 7 genes and the proliferative capacity of different non-MSC cell lines were assessed for comparison. Our analyses revealed that correlation between gene expression and proliferation was consistently reduced with the introduction of non-MSC cell lines; therefore this set of 7 genes may be more strongly associated with MSC proliferative quality. These correlative methods may be further used to identify additional markers that exhibit strong correlation with a particular MSC quality such as differentiation or immune suppression potential. Our results pave the way toward the identification of specific gene markers that could rapidly determine the quality of an MSC population for a particular cellular therapy in lieu of an extended in vitro or in vivo assay. Microarray gene expression analysis with confirmation of genes by RT-qPCR
Project description:The properties of MSCs can be affected by long term culture, therefore casting doubt over the ability of late passage MSCs to accurately recapitulate their biology. Additionally, assumption within the scientific community is often made that early passage MSCs are still representative of the primary MSC population, however, little research has been done to support this. We compared the transcriptomic profiles of murine MSCs freshly isolated from the long bones to MSCs that had been expanded in culture for 10 days. Interestingly, we identified that a single passage in culture induced extensive alterations to MSC molecular signatures associated with cell cycling, differentiation and immune response.
Project description:Molecular profiles of mesenchymal stem cells (MSCs) are critically needed to standardize the composition and effectiveness of MSC therapeutics. This study employs RNA sequencing to identify genes to be used in concert with CD264 as a molecular profile of aging MSCs at a clinically relevant culture passage. CD264- and CD264+ populations were isolated by fluorescence-activated cell sorting from passage 4 MSC cultures. Donor-matched CD264-/+ mRNA samples from 5 donors were subjected to pair-ended, next-generation sequencing. An independent set of 5 donor MSCs was used to validate differential expression of select genes with quantitative reverse transcription PCR. CD264+ cells accounted for 15% to 60% of the cells in MSC cultures and exhibited an aging phenotype. Pairwise differential expression analysis identified 2,322 downregulated genes and 2,695 upregulated genes in CD264+ MSCs relative to donor-matched CD264- MSCs with a Benjamini-Hochberg adjusted p-value (BH padj) < 0.1. Nearly 25% of these genes were unique to CD264-/+MSCs and not differentially expressed at a significance level of BH padj < 0.1 in previous RNA sequencing studies of early- vs. late-passage MSCs. Kyoto Encylopedia of Genes and Genomes pathways for DNA replication, cell cycle, spliceosome, RNA transport and ribosome biogenesis were downregulated in CD264+ MSCs and extracellular matrix-receptor interactions was upregulated (BH padj < 0.1). Pathway results were confirmed by Database for Annotation, Visualization, and Integrated Discovery gene set enrichment analysis. Least Absolute Shrinkage and Selection Operator regression was performed on the most significant genes and pathways and identified microtubule-associated protein 1A (MAP1A) and pituitary tumor-transforming gene 1 (PTTG1) as signature genes of CD264+ MSCs. For both the sequencing and validation sets, the combination of MAP1A and PTTG1 expression clustered MSC samples into distinct groups that had the correct CD264 classification with an accuracy of 100% (p ≤ 0.01). This study provides the first linkage of MAP1A upregulation to aging, CD264, and stem cells, and confirms previous reports of PTTG1 downregulation in aging MSCs. Our findings have application as quality metrics to standardize the composition of MSC therapies and as molecular targets to slow/reverse cellular aging.
Project description:Human mesenchymal stem cells or multipotent stromal cells (MSCs) are of interest for clinical therapy, in part because of their capacity for proliferation and differentiation. However, results from clinical trials and in vitro models have been variable, possibly due to MSC heterogeneity and a lack of standardization between MSC in vitro expansion protocols. Here we defined changes in MSCs during expansion in vitro. In low density cultures, MSCs expand through distinct lag, exponential growth and stationary phases. We assayed cultures of passage 2 human MSCs from three donors at low density (50 cells/cm2) at about 5% confluence on Day 2 and after the cultures had expanded to about 70% confluence on Day 7. On Day 2 genes involved in cell division were up-regulated. On Day 7 genes for cell development were up-regulated. The variations between three donors were less than the variation within the expansion of MSCs from a single donor. The microarray data for selected genes were confirmed by real-time PCR, ELISA and FACScan. About 50% of cells at Day 2 were in S-phase compared to 10% at Day 7. The results demonstrated major differences in early and late stage cultures of MSCs that should be considered in using the cells in experiments and clinical applications. Experiment Overall Design: We assayed cultures of passage 2 human MSCs from three donors at low density (50 cells/cm2) at about 5% confluence on Day 2 and after the cultures had expanded to about 70% confluence on Day 7.
Project description:Mesenchymal stromal cells (MSCs) are multipotent stem cells with potent immunosuppressive and trophic support functions. Although bone marrow is considered the golden standard to isolate classical MSCs (BM-MSC), MSC-like cells are currently also derived from other, more easily accessible extra-embryonic tissues such as the umbilical cord. In this study we compared the gene expression profile of human Wharton's jelly explant-derived MSC cultures with two adult MSC populations derived from bone marrow, namely BM-MSC and multipotent adult progenitor cells (MAPC). Here we demonstrate, by using genome wide gene expression analysis, that WJ-MSCs intrinsically have a differential gene expression profile compared to the adult MSCs. Gene ontology analysis revealed an increased expression of genes associated with cell-adhesion, proliferation, and immune system functioning. Furthermore, in comparison to adult MSC, stem cells from the Wharton’s jelly highly express genes involved in neurotrophic support (e.g. LIF, BDNF, NTF3). Such enhanced signatures make WJ-MSC an attractive candidate for cell-based therapy in neurodegenerative and immune-mediated CNS disorders such as multiple sclerosis or amyotrophic lateral sclerosis.
Project description:The efficacy of mesenchymal stromal cell (MSC) therapy is thought to depend on the intrinsic heterogeneity of MSC cultures isolated from different tissue sources as well as individual MSCs isolated from the same tissue source, neither of which is well understood. The horse model, in contrast to human and mouse, allows for simultaneous sample collection from multiple tissues of the same animal, which circumvents the inter-donor variation in MSC cultures observed in other models. In the present study, we performed single-cell RNA sequencing (scRNA-seq) on primary equine MSCs that were collected from three donor-matched tissue sources; adipose tissue (AT), bone marrow (BM), and peripheral blood (PB). We observed both inter- and intra-source heterogeneity across the three sources of equine MSCs.