Estrogen-Induced Gene Expression in Bone Marrow c-kit+ Stem Cells and Stromal Cells: Identification of Specific Biological Processes Involved in the Functional Organization of the Stem Cell Niche

2008 ◽  
Vol 17 (6) ◽  
pp. 1153-1164 ◽  
Author(s):  
Caroline Lemieux ◽  
Isabelle Cloutier ◽  
Jean-François Tanguay
Blood ◽  
2018 ◽  
Vol 131 (19) ◽  
pp. 2111-2119 ◽  
Author(s):  
Rafael Kramann ◽  
Rebekka K. Schneider

Abstract Myofibroblasts are fibrosis-driving cells and are well characterized in solid organ fibrosis, but their role and cellular origin in bone marrow fibrosis remains obscure. Recent work has demonstrated that Gli1+ and LepR+ mesenchymal stromal cells (MSCs) are progenitors of fibrosis-causing myofibroblasts in the bone marrow. Genetic ablation of Gli1+ MSCs or pharmacologic targeting of hedgehog (Hh)-Gli signaling ameliorated fibrosis in mouse models of myelofibrosis (MF). Moreover, pharmacologic or genetic intervention in platelet-derived growth factor receptor α (Pdgfrα) signaling in Lepr+ stromal cells suppressed their expansion and ameliorated MF. Improved understanding of cellular and molecular mechanisms in the hematopoietic stem cell niche that govern the transition of MSCs to myofibroblasts and myofibroblast expansion in MF has led to new paradigms in the pathogenesis and treatment of MF. Here, we highlight the central role of malignant hematopoietic clone-derived megakaryocytes in reprogramming the hematopoietic stem cell niche in MF with potential detrimental consequences for hematopoietic reconstitution after allogenic stem cell transplantation, so far the only therapeutic approach in MF considered to be curative. We and others have reported that targeting Hh-Gli signaling is a therapeutic strategy in solid organ fibrosis. Data indicate that targeting Gli proteins directly inhibits Gli1+ cell proliferation and myofibroblast differentiation, which results in reduced fibrosis severity and improved organ function. Although canonical Hh inhibition (eg, smoothened [Smo] inhibition) failed to improve pulmonary fibrosis, kidney fibrosis, or MF, the direct inhibition of Gli proteins ameliorated fibrosis. Therefore, targeting Gli proteins directly might be an interesting and novel therapeutic approach in MF.


2020 ◽  
Vol 21 (2) ◽  
pp. 539
Author(s):  
Vitaly Vodyanoy ◽  
Oleg Pustovyy ◽  
Ludmila Globa ◽  
Randy J. Kulesza ◽  
Iryna Sorokulova

Stem cells are nurtured and regulated by a specialized microenvironment known as stem cell niche. While the functions of the niches are well defined, their structure and location remain unclear. We have identified, in rat bone marrow, the seat of hematopoietic stem cells—extensively vascularized node-like compartments that fit the requirements for stem cell niche and that we called hemmules. Hemmules are round or oval structures of about one millimeter in diameter that are surrounded by a fine capsule, have afferent and efferent vessels, are filled with the extracellular matrix and mesenchymal, hematopoietic, endothelial stem cells, and contain cells of the megakaryocyte family, which are known for homeostatic quiescence and contribution to the bone marrow environment. We propose that hemmules are the long sought hematopoietic stem cell niches and that they are prototypical of stem cell niches in other organs.


Author(s):  
Valeria Perugini ◽  
Matteo Santin

Extracellular matrix-derived products (e.g. Matrigel) are widely used for in vitro cell cultures both as two-dimensional (2D) substrates and as three-dimensional (3D) encapsulation gels because of their ability to control cell phenotypes through biospecific cues. However, batch-to-batch variations, poor stability, cumbersome handling, and the relatively high costs strictly limit their use. Recently, a new substrate known as PhenoDrive-Y has been used as 2D coating of tissue culture plastic showing to direct the bone marrow mesenchymal stromal cells (MSCs) toward the formation of 3D spheroids. When organized into 3D spheroids, the MSCs expressed levels of pluripotency markers and of paracrine angiogenic activity higher than those of the MSCs adhering as fibroblast-like colonies on tissue culture plastic. The formation of the spheroids was attributed to the properties of this biomaterial that resemble the main features of the basement membrane by mimicking the mesh structure of collagen IV and by presenting the cells with orderly spaced laminin bioligands. In this study, PhenoDrive-Y was compared to Matrigel for its ability to drive the formation of perivascular stem cell niche-like structures in 2D co-culture conditions of human endothelial cells and adult bone marrow MSCs. Morphological analyses demonstrated that, when compared to Matrigel, PhenoDrive-Y led endothelial cells to sprout into a more consolidated tubular network and that the MSCs nestled as compact spheroids above the anastomotic areas of this network resemble more closely the histological features of the perivascular stem cell niche. A study of the expressions of relevant markers led to the identification of the pathways linking the PhenoDrive-Y biomimicking properties to the acquired histological features, demonstrating the enhanced levels of stemness, renewal potential, predisposition to migration, and paracrine activities of the MSCs.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 559-559
Author(s):  
Sarah Rivkah Vaiselbuh ◽  
Morris Edelman ◽  
Jeffrey Michael Lipton ◽  
Johnson M. Liu

Abstract Abstract 559 Introduction: Different cellular components of the normal hematopoietic niche have been identified. However, the niche for malignant hematopoiesis remains to be elucidated. Recent work of other groups has suggested that hematopoietic stem cells (HSC) within the bone marrow anchor themselves in place by attaching to osteoblasts and/or vascular sinusoid endothelial cells. We have recently identified mesenchymal stem cells (MSC) as niche-maker cells and found a crucial role of the SDF-1/CXCR4 axis in this process. Stromal Derived Factor-1 (SDF-1/CXCL12) regulates stem cell trafficking and the cell cycle via its receptor CXCR4. Methods: Polyurethane scaffolds, coated in vitro with human bone marrow MSC, were implanted subcutaneously in non-irradiated NOD/SCID mice. CD34+ HSC or primary AML cells (from a leukapheresis product) were injected either in situ or retro-orbitally in the mice and analyzed for engraftment. The mice were treated twice per week with in situ injections of SDF-1, AMD3100 (a CXCR4 antagonist) or PBS (control). After 2 to 4 weeks, the scaffolds were processed and evaluated for cell survival in the mesenchymal niche by immunohistochemistry. Results: We created in vitro MSC-coated scaffolds that retained inoculated AML cells in the presence of SDF-1, while AML cells seeded on empty scaffolds were not retained. In vivo in NOD/SCID mice, the MSC-coated scaffolds, in the presence of SDF-1 enabled homing of both in situ injected normal CD34+ HSC and retroorbital- or in situ injected primary human AML cells. The scaffolds were vascularized and showed osteoclasts and adipocytes present, suggestive of an ectopic human bone marrow microenvironment in the murine host. Finally, the SDF-1-treated scaffolds showed proliferation of the MSC stromal layer with multiple adherent AML cells, while in the AMD3100-treated scaffolds the stromal lining was thin and disrupted at several points, leaving AML cells free floating in proximity. The PBS-treated control-scaffold showed a thin single cell MSC stromal layer without disruption, with few AML cells attached. Conclusion: The preliminary data of this functional ectopic human microenvironment in NOD/SCID mice suggest that AMD3100 (a CXCR4 antagonist) can disrupt the stem cell niche by modulation of the mesenchymal stromal. Further studies are needed to define the role of mesenchymal stem cells in maintaining the hematopoietic/leukemic stem cell niche in vivo. In Vivo Leukemia Stem Cell Niche: (A) Empty polyurethane scaffold. (B)Vascularization in SQ implanted MSC-coated scaffold (s) niche in NOD/SCID mice. (C) DAB Peroxidase (brown) human CD45 positive nests of AML cells (arrows) 1 week after direct in situ AML injection. (D) Human CD45 positive myeloid cells adhere to MSC in vivo (arrows). Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 561-561
Author(s):  
Manoj M Pillai ◽  
Xiaodong Yang ◽  
Mineo Iwata ◽  
Lynne Bemis ◽  
Beverly Torok-Storb

Abstract Abstract 561 Two functionally distinct stromal cell lines were isolated from a primary long term culture (LTC) established from aspirated human marrow. Designated HS5 and HS27a, the lines were immortalized and extensively characterized including expression profiles for both messenger (mRNA) and micro-RNA (miRNA, a recently described class of small non-coding RNAs that regulate gene expression by binding to target mRNAs to prevent their translation). HS5 was found to secrete growth factors that stimulate proliferation and differentiation of hematopoietic progenitors (G-CSF, IL-6, IL-1α and IL1β), whereas HS27a expresses activities associated with the stem cell niche (SDF-1αa, angiopoietin-1 etc). In keeping with this HS5 conditioned media stimulated proliferation and differentiation of isolated CD34+ cells whereas HS27a supported CD34+ cells in an undifferentiated state. When cultured together to better mimic in vivo cell-cell interactions, the gene expression of HS27a and HS5 combined differed from the expected sum of the two parts, exemplified by the 5-fold down regulation of SDF-1α. Comparisons of miRNA expression profiles of HS5 and HS27a determined that mir-886-3p, (previously described by deep sequencing of small RNA libraries) was expressed > 40 fold in HS5 compared to HS27a, this was then confirmed by quantitative RT-PCR. Given the abundance of mir-886-3p and the possibility that it could be secreted by HS5 and taken up by cells in contact with HS5, we tested its effect on gene expression in HS27a. Transcript levels of genes associated with the stem cell niche (Jagged1, BMP4, Angiopoietin-1, SDF-1α, VCAM-1 and N-Cadherin) were determined by quantitative RT-PCR after direct transfection of mir-886-3p precursors into HS27a cells and compared to appropriate controls. Results show SDF-1α mRNA expression was down-regulated by as much as 8 fold 3 days after transfection. Levels of secreted SDF-1α in culture media, as determined by ELISA, were also decreased. Since SDF-1α is a chemokine known to be critical for the homing of hematopoietic stem and progenitor cells to their niche, the functional significance of the SDF-1α down-regulation by mir-886-3p was confirmed by decreased chemotaxis of T-lymphocytic cells (Jurkat) following miRNA transfection of stromal cells. To determine if mir-886-3p directly effects the SDF-1α transcript, the 1.5 kbp 3'untranslated region (UTR) of SDF-1α gene was cloned downstream of the luciferase gene, and co-transfected with mir-886-3p into HS27a cells. Results showed the luciferase activity was down-regulated greater than 50% in the presence of mir-886-3p, suggesting a direct effect on the SDF-1 α transcript. Given the concern over the relevance of immortalized cell lines we investigated Mir-886-3p expression in primary marrow stromal cells at early passage sorted on the basis of +/- expression of CD146. (CD146 or MCAM has been reported to define a population that supports the hematopoietic stem/ precursor cell niche and is expressed by HS27a and not HS5 cells). Results indicated that the CD146+ stromal cells had significantly lower expression of mir-886-3p when compared to CD146- cells. In summary, these data suggest a role for miRNA in modulating the expression of gene products that are associated with the hematopoietic stem cell niche. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2008 ◽  
Vol 112 (8) ◽  
pp. 3026-3035 ◽  
Author(s):  
Jean-Jacques Lataillade ◽  
Olivier Pierre-Louis ◽  
Hans Carl Hasselbalch ◽  
Georges Uzan ◽  
Claude Jasmin ◽  
...  

Abstract Primary myelofibrosis (PMF) is the rarest and the most severe Philadelphia-negative chronic myeloproliferative syndrome. By associating a clonal proliferation and a mobilization of hematopoietic stem cells from bone marrow to spleen with profound alterations of the stroma, PMF is a remarkable model in which deregulation of the stem cell niche is of utmost importance for the disease development. This paper reviews key data suggesting that an imbalance between endosteal and vascular niches participates in the development of clonal stem cell proliferation. Mechanisms by which bone marrow niches are altered with ensuing mobilization and homing of neoplastic hematopoietic stem cells in new or reinitialized niches in the spleen and liver are examined. Differences between signals delivered by both endosteal and vascular niches in the bone marrow and spleen of patients as well as the responsiveness of PMF stem cells to their specific signals are discussed. A proposal for integrating a potential role for the JAK2 mutation in their altered sensitivity is made. A better understanding of the cross talk between stem cells and their niche should imply new therapeutic strategies targeting not only intrinsic defects in stem cell signaling but also regulatory hematopoietic niche–derived signals and, consequently, stem cell proliferation.


Author(s):  
Vitaly Vodyanoy ◽  
Oleg Pustovyy ◽  
Ludmila Globa ◽  
Randy J Kulesza Jr ◽  
Iryna Sorokulova

Stem cells are nurtured and regulated by a specialized microenvironment known as stem cell niche. While the functions of the niches are well defined, their structure and location remain unclear. We have identified in rat bone marrow, the seat of hematopoietic stem cells, extensively vascularized node-like compartments that fit the requirements for stem cell niche and which we called hemmules. Hemmules are round or oval structures of about one millimeter in diameter that are surrounded by a fine capsule, have afferent and efferent vessels, are filled with the extracellular matrix and mesenchymal, hematopoietic, endothelial stem cells, and contain cells of the megakaryocyte family, which are known for homeostatic quiescence and contribution to the bone marrow environment. We propose that hemmules are the long sought hematopoietic stem cell niches and that they are prototypical of stem cell niches in other organs.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. SCI-49-SCI-49
Author(s):  
Paul S. Frenette ◽  
Simón Méndez-Ferrer ◽  
Daniel Lucas-Alcaraz ◽  
Michela Batista ◽  
Sergio Lira ◽  
...  

Abstract Abstract SCI-49 The concept of stem cell niche, proposed by Schofield 30 years ago, refers to the ability of the microenvironment to regulate stem cell fate. The niche provides critical signals allowing hematopoietic stem cells (HSC) to survive, and if so, whether to remain in or to leave the niche (mobilization), or whether to remain quiescent or divide. Some of these signals originate locally from the niche cell(s) but others are coming from afar. For example, we have found that signals from the sympathetic nervous system (SNS) promote the release of HSCs from the bone marrow (BM) niche. Under steady-state conditions, HSC egress in blood is orchestrated in a circadian manner where the fluctuations of circulating HSCs/progenitors are matched with antiphase oscillations in the expression of Cxcl12 mRNA in the BM microenvironment. These oscillations are entrained in the brain by the molecular clock through the local delivery of norepinephrine by SNS nerve terminals in the BM, and transmitted specifically by the β3 adrenergic receptor (Adrβ3) expressed on CXCL12-producing stromal cells, thereby leading to the cyclical degradation of the Sp1 transcription factor. In humans, the circadian release of HSC is inverted compared to rodents and may influence the stem cell yield even when mobilization is enforced by granulocyte colony-stimulating factor (G-CSF), suggesting the potential benefit to harvest HSCs in the clinic at the optimal circadian time. Given the coupling of nervous signals with the stem cell niche, we would expect that the stromal cell forming the niche would be intimately associated with nerve fibers. We have recently found using transgenic mice expressing the green fluorescent protein (GFP) under the Nestin promoter elements (Nes-Gfp), that GFP+ cells (referred to as Nestin+) form a HSC niche in the marrow. Nestin+ cells comprise a relatively small subset (0.08 ± 0.01%) of total BM nucleated cells that is anatomically and functionally associated with the vast majority of CD150+ CD48- Lin- HSCs near blood vessels and SNS fibers of the BM. Nestin+ niche cells express high levels of core genes regulating HSC retention (Cxcl12, Kit ligand, Vcam-1, Angiopoietin-1), and these genes are downregulated by mobilization induced by G-CSF or administration of Adrβ3 agonists. We have identified putative Nestin+ niche cells as bona fide mesenchymal stem cells (MSCs) since they can be propagated as single clonal spheres capable of self-renewal, dramatic in vivo expansion, and multipotency to form osteoblasts, adipocytes, and chondocytes. These data argue for a unique bone marrow niche formed by the pairing of the two rare stem cells, mesenchymal and hematopoietic, that exist in the marrow. Co-authors: Simón Méndez-Ferrer, Ph.D., Daniel Lucas, Ph.D., Michela Batista, Ph.D., Sergio A. Lira, M.D., Mount Sinai School of Medicine, New York, NY; Tatyana V. Michurina, Ph.D., Grigori N. Enikolopov Ph.D., Cold Spring Harbor Laboratory, Cold Spring Harbor, NY Disclosures Frenette: Glycomimetic: Research Funding.


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