Project description:Methylation data for MDS bone marrow derived MSCs before and after 5-Azacitidine treatment. Methylation profiles were measured using the Infinium Human MethylationEPIC BeadChip (Illumina). There are 5 healthy MSC and 8 high-risk MDS-MSC samples, untreated and treated with 5-Azacitidine in vitro.
Project description:Mesenchymal stromal cells (MSC) are crucial components of the bone marrow (BM) microenvironment essential for regulating self-renewal, survival and differentiation of hematopoietic stem/progenitor cells (HSPC) in the stem cell niche. MSC are functionally and phenotypically altered in myelodysplastic syndromes (MDS), contributing to disease progression. MDS MSC do not harbor recurrent genetic alterations but have been shown to exhibit an altered methylome compared to MSC from healthy controls. We examined growth, differentiation and HSPC-supporting capacity of ex vivo expanded MSC from MDS patients in comparison to age-matched healthy controls after direct treatment in vitro with the hypomethylating agent azacitidine (AZA). We show that AZA exerts a direct effect on MSC by modulating their differentiation potential. Osteogenesis was significantly boosted in healthy MSC while adipogenesis was inhibited in both healthy and MDS MSC. In co-culture experiments, both AZA treated MDS MSC and healthy MSC exhibited enhanced support of non-clonal HSPC which was associated with increased cell cycle induction. Conversely, clonal MDS HSPC were inhibited by contact with AZA treated MSC. RNA-sequencing analyses of stromal cells revealed changes in pathways essential for HSPC support as well as in immune regulatory pathways. In sum, our data demonstrate that AZA treatment of stromal cells leads to upregulation of HSPC-supportive genes and cell cycle induction in co-cultured healthy HSPC, resulting in a proliferative advantage over clonal HSPC. Thus, restoration of functional hematopoiesis by AZA may be driven by activated stromal support factors in MSC providing cell cycle cues to healthy HSPC.
Project description:Ineffective hematopoiesis is a hallmark of myelodysplastic syndromes (MDS). Hematopoietic alterations in MDS patients strictly correlate with microenvironment dysfunctions, eventually affecting also the mesenchymal stromal cells (MSCs) compartment. Stromal cells are indeed epigenetically reprogrammed to cooperate with leukemic cells and propagate the disease as "tumor unit"; therefore, changes on MSCs epigenetic profile might contribute to the hematopoietic perturbations typical of MDS. Here, we unveil that the histone variant macroH2A1 (mH2A1) regulates the crosstalk between epigenetics and inflammation in MDS-MSCs, potentially affecting their hematopoietic support ability. We show that the mH2A1 splicing isoform mH2A1.1 accumulates in MDS-MSCs, correlating with the expression of the Toll-like receptor 4 (TLR4), an important pro-tumor activator of MSC phenotype associated to a pro-inflammatory behavior. MH2A1.1-TLR4 axis was further investigated in HS-5 stromal cells after ectopic mH2A1.1 overexpression (mH2A1.1-OE). Proteomic data confirmed the activation of a pro-inflammatory signature associated to TLR4 and nuclear factor kappa B (NFkB) activation. Moreover, mH2A1.1-OE proteomic profile identified several upregulated proteins associated to DNA and histones hypermethylation, including S-adenosylhomocysteine hydrolase, a strong inhibitor of DNA methyltransferase and of the methyl donor S-adenosyl-methionine (SAM). HPLC analysis confirmed higher SAM/SAH ratio along with a metabolic reprogramming. Interestingly, an increased LDHA nuclear localization was detected both in mH2A1.1-OE cells and MDS-MSCs, probably depending on MSC inflammatory phenotype. Finally, coculturing healthy mH2A1-OE MSCs with CD34+ cells, we found a significant reduction in the number of CD34+ cells, which was reflected in a decreased number of colony forming units (CFU -Cs). These results suggest a key role of mH2A1.1 in driving the crosstalk between epigenetic signaling, inflammation and cell metabolism networks in MDS-MSCs.
Project description:The bone marrow (BM) stroma in myeloid neoplasms is altered and it is hypothesized that this cell compartment may also harbor clonal somatically acquired mutations. By exome sequencing of in vitro expanded mesenchymal stromal cells (MSCs) from n = 98 patients with myelodysplastic syndrome (MDS) and n = 28 healthy controls we show that these cells accumulate recurrent mutations in genes such as ZFX (n = 8/98), RANK (n = 5/98), and others. MDS derived MSCs display higher mutational burdens, increased replicative stress, senescence, inflammatory gene expression, and distinct mutational signatures as compared to healthy MSCs. However, validation experiments in serial culture passages, chronological BM aspirations and backtracking of high confidence mutations by re-sequencing primary sorted MDS MSCs indicate that the discovered mutations are secondary to in vitro expansion but not present in primary BM. Thus, we here report that there is no evidence for clonal mutations in the BM stroma of MDS patients.
Project description:Myelodysplastic syndromes (MDS) are a group of clonal disorders of hematopoietic stem cells. Mesenchymal stem cells (MSC) are the progenitors of the Bone Marrow (BM) stroma and have been involved in the physiopathology of MDS. The presence of cytogenetic aberrations on MSC from MDS patients is controversial. The aim of the study is to characterize BM derived MSC from patients with MDS using: kinetic studies, immunophenotyping, fluorescent in situ hybridisation (FISH) analysis and genetic changes by array based comparative genomic hybridization (array-CGH). 32 cases of untreated MDS were included in the study. MSC from MDS achieved confluence at a slower rate than donor-MSC, and the antigenic expression of CD105 and CD104 was also lower. Array-CGH studies showed DNA genomic changes that were proved not to be somatic, and gains were more frequent than looses. The results of array-CGH were confirmed by FISH. When an unsupervised hierarchical cluster analysis was performed two clusters were identified: one of them included the 5q- syndrome patients, while the other incorporated the rest of the MDS patients. Our results shows, for the first time, that MSC from MDS display genomic aberrations, assessed by array-CGH and FISH, some of them specially linked to particular MDS subtypes. Keywords: Genomic comparison between mesenchymal cells
Project description:As an essential cellular component of the bone marrow (BM) microenvironment mesenchymal stromal cells (MSC) play a pivotal role for the physiological regulation of hematopoiesis, in particular through the secretion of cytokines and chemokines. Mass spectrometry (MS) facilitates the identification and quantification of a large amount of secreted proteins (secretome), but can be hampered by the false-positive identification of contaminating proteins released from dead cells or derived from cell medium. To reduce the likelihood of contaminations we applied an approach combining secretome and proteome analysis to characterize the physiological secretome of BM derived human MSC. Our analysis revealed a secretome consisting of 315 proteins. Pathway analyses of these proteins revealed a high abundance of proteins related to cell growth and/or maintenance, signal transduction and cell communication thereby representing key biological functions of BM derived MSC on protein level. Within the MSC secretome we identified several cytokines and growth factors such as VEGFC, TGF-β1, TGF-β2 and GDF6 which are known to be involved in the physiological regulation of hematopoiesis. By comparing the peptide patterns of secretomes and cell lysates 17 proteins were identified as candidates for proteolytic processing. Taken together, our combined MS work-flow reduced the likelihood of contaminations and enabled us to carve out a specific overview about the composition of the secretome from human BM derived MSC. This methodological approach and the specific secretome signature of BM derived MSC may serve as basis foffuture comparative analyses of the interplay of MSC and HSPC in patients with hematological malignancies.
Project description:Myelodysplastic syndromes(MDS) are a group of heterogeneous disease. Emerging evidence has shown the bone marrow(BM) endothelial progenitor cells(EPCs) are also heterogeneity. To uncover the underlying mechanism of heterogeneous BM EPCs in different types of MDS patients. RNA sequencing(RNA-seq) analyses were performed to analyse BM EPCs at day 7 in culture from lower-risk MDS(N=3), higher-risk MDS(N=3), acute myloid leukemia(AML) patients(N=3) and healthy donors(HDs)(N=3). We analysed the hematopoiesis- and immune-related genes and pathways.
Project description:Control of oxidative stress in the bone marrow (BM) is key for maintaining the balance between self-renewal, proliferation, and differentiation of hematopoietic cells. Breakdown of this regulation can lead to diseases characterized by BM failure such as the myelodysplastic syndromes (MDS). To better understand the role of oxidative stress in MDS development, we compared protein carbonylation as an oxidative stress marker in BM of patients with MDS and control subjects, and also patients with MDS under treatment with the iron chelator deferasirox.
Project description:We have demonstrated that DICER1 (a key enzyme of miRNA biogenesis) was underexpressed in myelodysplastic syndrome MSC. We hypothesize that those MSC harbored a deregulated pattern of miRNA versus healthy donors MSC.
Project description:Genetic and epigenetic lesions within hematopoietic cell populations drive diverse hematological malignancies. Myelodysplastic syndromes (MDS) are a group of myeloid neoplasms affecting the hematopoietic stem cells characterized by recurrent genetic abnormalities, myelodysplasia (a pathological definition of abnormal bone marrow structure), ineffective hematopoiesis resulting in blood cytopenia, and a propensity to evolve into acute myelogenous leukemia. Although there is evidence that the accumulation of a set of genetic mutations is an essential event in MDS, there is an increased appreciation of the contribution of specific microenvironments, niches, in the pathogenesis of MDS and response to treatment. In physiologic hematopoiesis, niches are critical functional units that maintain hematopoietic stem and progenitor cells and regulate their maturation into mature blood cells. In MDS and other hematological malignancies, altered bone marrow niches can promote the survival and expansion of mutant hematopoietic clones and provide a shield from therapy. In this review, we focus on our understanding of the composition and function of hematopoietic niches and their role in the evolution of myeloid malignancies, with an emphasis on MDS.