TGF-β Signaling in Fetal Mesenchymal Progenitor Cells Plays an Essential Role in the Emergence of Bone Marrow Hematopoietic Niches

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3847-3847
Author(s):  
Grazia Abou Ezzi ◽  
Teerawit Supakorndej ◽  
Jingzhu Zhang ◽  
Joseph R. Krambs ◽  
Hamza Celik ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Essential Role ◽  
Suppressive Effect ◽  
Mesenchymal Cells ◽  
Lineage Specification ◽  
Mapk Activation ◽  
Hematopoietic Stem

Abstract Hematopoietic stem/progenitor cells (HSPC) reside in a unique microenvironment within the bone marrow called the bone marrow hematopoietic niche. Mesenchymal stromal cells, including CXCL12-abundant reticular (CAR) cells, osteoblasts, arteriolar pericytes, and adipocytes are all important components of the niche. The development and maintenance of mesenchymal stromal cells in the bone marrow is not well characterized. A prior study suggested that these stromal cells are derived from two distinct types of mesenchymal stem/progenitor cells (MSPCs). Primitive MSPCs are present in fetal bone and are responsible for osteoblasts, CAR cells, and adipocytes through approximately 3 weeks after birth, and definitive MPSCs are present at birth and generate bone marrow mesenchymal stromal cells in adult mice. In this study, we abrogated transforming growth factor-b (TGF-β) signaling in MSPCs by deleting Tgfbr2in mesenchymal cells using a doxycycline-repressible Sp7(osterix)-Cre transgene (Osx-Cre).We previously reported that loss of TGF-βsignaling during fetal development results in a marked expansion of CAR cells and adipocytes in the bone marrow, while osteoblasts are significantly reduced. These stromal alterations are associated with significant defects in hematopoiesis, including a shift from lymphopoiesis to myelopoiesis. However, hematopoietic stem cell function is preserved. Interestingly, TGF-βsignaling is dispensable for the maintenance of mesenchymal cells in the bone marrow after birth under steady state conditions. These data show that TGF-βplays an essential role in the lineage specification of fetal but not definitive MSPCs and is required for the establishment of normal hematopoietic niches in fetal and perinatal bone marrow. Canonical TGF-bsignaling is dependent on SMAD4. To investigate whether MSPC lineage specification by TGF-bis dependent on SMAD4, we generated Osx-Cre Smad4Δ/Δmice. Osx-Cre Smad4Δ/Δmice are runted to a similar degree as Osx-CreTgfbr2Δ/Δmice secondary to a loss of mature osteoblasts. However, the magnitude of the increase in bone marrow adiposity is significantly reduced in Osx-Cre Smad4∆/∆mice compared to Osx-Cre, Tgfbr2Δ/Δmice. These data suggested that non-canonical signaling contributes to the suppressive effect of TGF-b on adipogenesis. To test this hypothesis, we generated cultures of mesenchymal stromal cells from wildtype neonatal bone marrow. As expected, in wildtype cultures, the addition of TGF-bpotently suppressed adipocyte formation. To assess the role of MAPK activation on the suppression of adipogenesis by TGF-b, we pharmacologically inhibited MAPK activation. Inhibition of MAPK alone did not suppress adipocyte formation. However, it completely blocked the suppressive effect of TGF-bon adipogenesis. Prior studies showed that phosphorylation of serine 82 of PPARgby MAPK decreases its transcriptional activity. Since PPARgis a master regulator of adipogenesis, we assessed the ability of TGF-b to induce PPARgphosphorylation. Indeed, the addition of TGF-b to the MSPC cultures resulted in reproducible PPARgphosphorylation. These data suggest that TGF-b suppresses adipocyte specification of MSPCs, in part, in a MAPK-dependent fashion through phosphorylation of PPARg. In summary, our data suggest that TGF-b plays a key role in the lineage specification of fetal MSPCs during development and is required for the proper development of fetal hematopoietic niches in the bone marrow. The contribution of TGF-b signaling in MSPCs to the stromal and hematopoietic response to different stressors is an active area of investigation. Disclosures No relevant conflicts of interest to declare.

scholarly journals EBF1 As a Novel Regulator of Bone Marrow Mesenchymal Stromal Progenitors

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 96-96
Author(s):  
Marta Derecka ◽  
Senthilkumar Ramamoorthy ◽  
Pierre Cauchy ◽  
Josip Herman ◽  
Dominic Grun ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Myeloid Cells ◽  
Bone Marrow Niche ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Stem And Progenitor Cells

Abstract Hematopoietic stem and progenitor cells (HSPC) are in daily demand worldwide because of their ability to replenish entire blood system. However, the in vitro expansion of HSPC is still a major challenge since the cues from bone marrow microenvironment remain largely elusive. Signals coming from the bone marrow niche, and specifically mesenchymal stem and progenitor cells (MSPC), orchestrate maintenance, trafficking and stage specific differentiation of HSPCs. Although, it is generally accepted that MSPCs are essential for hematopoietic homeostasis and generating multiple types of stromal cells, the exact transcriptional networks regulating MSPCs are not well established. Early B-cell factor 1 (Ebf1) has been discovered as lineage-specific transcription factor governing B lymphopoiesis. Additionally, it has been shown to play important role in differentiation of adipocytes, which are a niche component supporting hematopoietic regeneration. Thus, in this study we seek to examine if Ebf1 has an alternative function in non-hematopoietic compartment of bone marrow, specifically in mesenchymal stromal cells that maintain proper hematopoiesis. Here, we identified Ebf1 as new transcription regulator of MSPCs activity. Mesenchymal progenitors isolated from Ebf1-/- mice show diminished capacity to form fibroblasticcolonies (CFU-F) indicating reduced self-renewal. Moreover, cells expanded from these colonies display impaired in vitro differentiation towards osteoblasts, chondrocytes and adipocytes. In order to test how this defective MSPCs influence maintenance of HSPCs, we performed long-term culture-initiating cell assay (LTC-IC). After 5 weeks of co-culture of Ebf1-deficient stromal cells with wild type HSPCs we could observe significantly decreased number of cobblestone and CFU colonies formed by primitive HSPCs, in comparison to co-cultures with control stromal cells. Furthermore, in vivo adoptive transfers of wild type HSPCs to Ebf1+/- recipient mice showed a decrease in the absolute numbers of HSPCs in primary recipients and reduced donor chimerism within the HSCP compartment in competitive secondary transplant experiments. Additionally, Prx1-Cre-mediated deletion of Ebf1 specifically in MSPCs of mice leads to reduced frequency and numbers of HSPCs and myeloid cells in the bone marrow. These results confirm that mesenchymal stromal cells lacking Ebf1 render insufficient support for HSPCs to sustain proper hematopoiesis. Interestingly, we also observed a reduced ability of HSPCs sorted from Prx1CreEbf1fl/fl mice to form colonies in methylcellulose, suggesting not only impaired maintenance but also hindered function of these cells. Moreover, HSPCs exposed to Ebf1-deficient niche exhibit changes in chromatin accessibility with reduced occupancy of AP-1, ETS, Runx and IRF motifs, which is consistent with decreased myeloid output seen in Prx1CreEbf1fl/fl mice. These results support the hypothesis that defective niche can cause epigenetic reprograming of HSPCs. Finally, single cell and bulk transcriptome analysis of MSPCs lacking Ebf1 revealed differences in the niche composition and decreased expression of lineage-instructive signals for myeloid cells. Thus, our study establishes Ebf1 as a novel regulator of MSPCs playing a crucial role in the maintenance and differentiation of HSPCs. Disclosures No relevant conflicts of interest to declare.

scholarly journals Aging of Bone Marrow Mesenchymal Stromal Cells: Hematopoiesis Disturbances and Potential Role in the Development of Hematologic Cancers

Cancers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 68
Author(s):  
Fulvio Massaro ◽  
Florent Corrillon ◽  
Basile Stamatopoulos ◽  
Nathalie Meuleman ◽  
Laurence Lagneaux ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Tumor Progression ◽  
Cancer Progression ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Cell Communication ◽  
Bone Marrow Niche ◽  
Hematopoietic Stem ◽  
Wide Range ◽  
Major Player

Aging of bone marrow is a complex process that is involved in the development of many diseases, including hematologic cancers. The results obtained in this field of research, year after year, underline the important role of cross-talk between hematopoietic stem cells and their close environment. In bone marrow, mesenchymal stromal cells (MSCs) are a major player in cell-to-cell communication, presenting a wide range of functionalities, sometimes opposite, depending on the environmental conditions. Although these cells are actively studied for their therapeutic properties, their role in tumor progression remains unclear. One of the reasons for this is that the aging of MSCs has a direct impact on their behavior and on hematopoiesis. In addition, tumor progression is accompanied by dynamic remodeling of the bone marrow niche that may interfere with MSC functions. The present review presents the main features of MSC senescence in bone marrow and their implications in hematologic cancer progression.

The role of children's bone marrow mesenchymal stromal cells in the ex vivo expansion of autologous and allogeneic hematopoietic stem cells

2015 ◽  
Vol 39 (10) ◽  
pp. 1099-1110 ◽  
Author(s):  
Iordanis Pelagiadis ◽  
Eftichia Stiakaki ◽  
Christianna Choulaki ◽  
Maria Kalmanti ◽  
Helen Dimitriou
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Ex Vivo ◽  
Ex Vivo Expansion ◽  
Hematopoietic Stem

scholarly journals Mast Cell-Activated Bone Marrow Mesenchymal Stromal Cells Regulate Proliferation and Lineage Commitment of CD34+ Progenitor Cells

2013 ◽  
Vol 4 ◽  
Author(s):  
Zoulfia Allakhverdi ◽  
Michael R. Comeau ◽  
Myriam Armant ◽  
Rachana Agrawal ◽  
Judith A. Woodfolk ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cell ◽  
Progenitor Cells ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Lineage Commitment

scholarly journals Deciphering Master Gene Regulators and Associated Networks of Human Mesenchymal Stromal Cells

Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 557
Author(s):  
Elena Sánchez-Luis ◽  
Andrea Joaquín-García ◽  
Francisco J. Campos-Laborie ◽  
Fermín Sánchez-Guijo ◽  
Javier De las Rivas
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Transcription Factors ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Cell Structure ◽  
Regulatory Gene ◽  
Human Mscs ◽  
Protein Activity ◽  
Hematopoietic Stem

Mesenchymal Stromal Cells (MSC) are multipotent cells characterized by self-renewal, multilineage differentiation, and immunomodulatory properties. To obtain a gene regulatory profile of human MSCs, we generated a compendium of more than two hundred cell samples with genome-wide expression data, including a homogeneous set of 93 samples of five related primary cell types: bone marrow mesenchymal stem cells (BM-MSC), hematopoietic stem cells (HSC), lymphocytes (LYM), fibroblasts (FIB), and osteoblasts (OSTB). All these samples were integrated to generate a regulatory gene network using the algorithm ARACNe (Algorithm for the Reconstruction of Accurate Cellular Networks; based on mutual information), that finds regulons (groups of target genes regulated by transcription factors) and regulators (i.e., transcription factors, TFs). Furtherly, the algorithm VIPER (Algorithm for Virtual Inference of Protein-activity by Enriched Regulon analysis) was used to inference protein activity and to identify the most significant TF regulators, which control the expression profile of the studied cells. Applying these algorithms, a footprint of candidate master regulators of BM-MSCs was defined, including the genes EPAS1, NFE2L1, SNAI2, STAB2, TEAD1, and TULP3, that presented consistent upregulation and hypomethylation in BM-MSCs. These TFs regulate the activation of the genes in the bone marrow MSC lineage and are involved in development, morphogenesis, cell differentiation, regulation of cell adhesion, and cell structure.

Human Hematopoietic Stem Cells and Leukemic Cells Form Cadherin-Catenin Based Junctional Complexes with Mesenchymal Stromal Cells

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1367-1367 ◽  
Author(s):  
Patrick Wuchter ◽  
Rainer Saffrich ◽  
Wolfgang Wagner ◽  
Frederik Wein ◽  
Mario Stephan Schubert ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Leukemia Cells ◽  
Feeder Layer ◽  
Hematopoietic Stem ◽  
Knock Down ◽  
Junctional Complexes

Abstract The interaction between human hematopoietic stem cells (HSC) and their niche plays a key role in regulating maintenance of “stemness” and differentiation. We have demonstrated that a feeder layer of human mesenchymal stromal cells (MSC) can serve as a surrogate model for the niche for human HSC. We could also show, MSC are intimately connected to one another by a novel kind of adhering junction, consisting of villiformto-vermiform cell projections (processus adhaerentes). With this background, we have analyzed the intercellular junctional complexes between HSC and MSC. In comparison, we also studied the cell-cell contacts between leukemia cells (LC) and MSC. MSC were derived from bone marrow aspirates from healthy voluntary donors. HSC were isolated from umbilical cord blood. Leukemia cells that were CD34+ were obtained from bone marrow aspirates from patients suffering from acute myeloid leukemia at the time point of initial diagnosis. After 24–48 hours of co-cultivation, we stained the cellular contacts with a panel of antibodies specific for various components of tight, gap and adherens junctions. Using advanced confocal laser scanning microscopy in combination with deconvolution and volume rendering software, we were able to produce 3D-images of intercellular junctions between HSC/MSC as well as between LC/MSC. To examine the specific function of N-cadherin, we analyzed the effect of siRNA knock down of N-cadherin in MSC upon co-cultures of HSC and MSC. Intercellular connections between HSC and MSC are mainly characterized by podia formation of the HSC linking to the adjacent MSC. At the intimate contact zone to the MSC, we have identified the cytoplasmic plaque proteins alpha- and beta-catenin, co-localized with the transmembrane glycoprotein N-cadherin. Additionally, we compared these findings with a similar setting consisting of human LC co-cultured with feeder-layer of MSC. Our results demonstrated that in comparison to HSC, the proportion of leukemia cells adherent to the feeder-layer is significantly lower and podia formation is less frequent (ratio 1:3). However, the mechanism of adhesion through cadherin-catenin-complex has remained the same. At a functional level, we found that siRNA knock down of N-cadherin in MSC resulted in decreased adhesion of HSC to MSC and in a reduction of cell divisions of HSC. These results confirm that direct cellular contact via N-cadherin-based junctions is essential for homing and adhesion of HSC to the cellular niche and subsequently for the regulation of self-renewal versus differentiation in HSC.

Muc1 Expression Identifies Human Self-Renewing Stem/Progenitor Populations and Is Elevated in AML CD34+ Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4040-4040
Author(s):  
Szabolcs Fatrai ◽  
Simon M.G.J. Daenen ◽  
Edo Vellenga ◽  
Jan J. Schuringa
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Stromal Cells ◽  
Bone Marrow Stromal Cells ◽  
Fold Increase ◽  
Marrow Stromal Cells ◽  
Muc1 Expression ◽  
Hematopoietic Stem ◽  
Cd34 Cells

Abstract Mucin1 (Muc1) is a membrane glycoprotein which is expressed on most of the normal secretory epithelial cells as well as on hematopoietic cells. It is involved in migration, adhesion and intracellular signalling. Muc1 can be cleaved close to the membrane-proximal region, resulting in an intracellular Muc1 that can associate with or activate various signalling pathway components such as b-catenin, p53 and HIF1a. Based on these properties, Muc1 expression was analysed in human hematopoietic stem/progenitor cells. Muc1 mRNA expression was highest in the immature CD34+/CD38− cells and was reduced upon maturation towards the progenitor stage. Cord blood (CB) CD34+ cells were sorted into Muc1+ and Muc1− populations followed by CFC and LTC-IC assays and these experiments revealed that the stem and progenitor cells reside predominantly in the CD34+/Muc1+ fraction. Importantly, we observed strongly increased Muc1 expression in the CD34+ subfraction of AML mononuclear cells. These results tempted us to further study the role of Muc1 overexpression in human CD34+ stem/progenitor cells. Full-length Muc1 (Muc1F) and a Muc1 isoform with a deleted extracellular domain (DTR) were stably expressed in CB CD34+ cells using a retroviral approach. Upon coculture with MS5 bone marrow stromal cells, a two-fold increase in expansion of suspension cells was observed in both Muc1F and DTR cultures. In line with these results, we observed an increase in progenitor counts in the Muc1F and DTR group as determined by CFC assays in methylcellulose. Upon replating of CFC cultures, Muc1F and DTR were giving rise to secondary colonies in contrast to empty vector control groups, indicating that self-renewal was imposed on progenitors by expression of Muc1. A 3-fold and 2-fold increase in stem cell frequencies was observed in the DTR and Muc1F groups, respectively, as determined by LTC-IC assays. To determine whether the above mentioned phenotypes in MS5 co-cultures were stroma-dependent, we expanded Muc1F and DTR-transduced cells in cytokine-driven liquid cultures. However, no proliferative advantage or increase in CFC frequencies was observed suggesting that Muc1 requires bone marrow stromal cells. In conclusion, our data indicate that HSCs as well as AML cells are enriched for Muc1 expression, and that overexpression of Muc1 in CB cells is sufficient to increase both progenitor and stem cell frequencies.

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