Modeling Osteoclast Defect and Altered Hematopoietic Stem Cell Niche in Osteopetrosis with Patient-Derived iPSCs

Abstract Background Patients with osteopetrosis present with defective bone resorption caused by the lack of osteoclast activity and hematopoietic alterations, but their bone marrow hematopoietic stem/progenitor cell and osteoclast contents might be different. Osteoclasts recently have been described as the main regulators of HSCs niche, however, their exact role remains controversial due to the use of different models and conditions. Investigation of their role in hematopoietic stem cell niche formation and maintenance in osteopetrosis patients would provide critical information about the mechanisms of altered hematopoiesis. We used patient-derived induced pluripotent stem cells (iPSCs) to model osteoclast defect and hematopoietic niche compartments in vitro. Methods iPSCs were generated from peripheral blood mononuclear cells of patients carrying TCIRG1 mutation. iPSC lines were differentiated first into hematopoietic stem cells-(HSCs), and then into myeloid progenitors and osteoclasts using a step-wise protocol. Then, we established different co-culture conditions with bone marrow-derived hMSCs and iHSCs of osteopetrosis patients as an in vitro hematopoietic niche model to evaluate the interactions between osteopetrotic-HSCs and bone marrow-derived MSCs as osteogenic progenitor cells. Results We first demonstrated myeloid-skewed hematopoietic differentiation potential of osteopetrotic iPSC-derived hematopoietic progenitors and phenotypically normal and functionally defective osteoclast formation. Upon co-culture with healthy iHSCs, the expression of the genes involved in HSC homing and maintenance (Ang-1, Sdf-1, Jagged-1, N-Cadherine, Kit-L, Opn) in osteopetrotic MSCs which revealed impaired osteogeneic differentiation, as well as their attraction ability over HSCs recovered significantly. Similar change in the phenotype of osteopetrotic iHSCs occured when they interacted with healthy MSCs. Conclusion Our results establish significant alterations in both MSC and HSC compartments of the hematopoietic niche in osteopetrosis patients, which are restored with normal MSC activity supporting the role of defective osteoclasts in all these processes.

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Matrix Glycoprotein Osteopontin Is a Stem Cell Niche Constituent That Constrains the Hematopoietic Stem Cell Pool Size.

Blood ◽

10.1182/blood.v104.11.664.664 ◽

2004 ◽

Vol 104 (11) ◽

pp. 664-664 ◽

Cited By ~ 2

Author(s):

Sebastian Stier ◽

Yon Ko ◽

Randolf Forkert ◽

Christoph Lutz ◽

Thomas Neuhaus ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Hematopoietic Stem Cell ◽

Stem Cell Niche ◽

Wild Type ◽

Hematopoietic Stem ◽

Hematopoietic Stem Cell Niche ◽

Cell Niche ◽

Stem Cell Pool

Abstract Stem cells reside in a physical niche where a balance of signals controls their growth, differentiation and death. Niche components have generally been defined in terms of cells and positive effects on stem cell maintenance or expansion. Here we define a role for a matrix glycoprotein that provides a constraining function in the hematopoietic stem cell niche. Osteopontin (OPN) is an abundant glycoprotein in bone that can function as either cytokine or cell adhesion mediator. It is known to be produced by multiple cells types including osteoblasts, cells recently defined to be a regulatory component of the hematopoietic stem cell niche. Using studies combining OPN deficient mice and exogenous OPN, we demonstrate that OPN modifies primitive hematopoietic cell numbers and function. In OPN deficient mice, increased primitive cell numbers were observed in vivo associated with reduced progenitors and reduced primitive cell apoptotic fraction. To determine whether the effect of OPN deficiency was stroma dependent, we performed in vitro stem cell assays on OPN−/− stroma and observed greater LTC-IC supportive capacity compared with wild type stroma. Furthermore, OPN−/− recipients showed a significantly higher proportion of hematopoietic stem cells after transplantation of OPN+/+ bone marrow in comparison to wild-type recipients, indicating that the OPN null microenvironment was sufficient to increase stem cell number. A reduction in apoptotic fraction was seen in primitive cells in the OPN−/− recipient marrows. A role for OPN in apoptosis was confirmed by exogenous OPN in in-vitro studies. Hypothesizing that OPN may serve as a physiologic constraint on stem cell pool size, we compared OPN−/− with wild type animals following parathyroid hormone activation of the stem cell niche. The expansion of stem cells by PTH was superphysiologic in the absence of OPN. Therefore, OPN is a restricting element of the stem cell niche, limiting the number of stem cells produced by niche activation. Extracellular matrix components such as OPN may serve as modulable, regulatory participants in the stem cell niche.

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Bone Marrow Adipocytes: The Enigmatic Components of the Hematopoietic Stem Cell Niche

Journal of Clinical Medicine ◽

10.3390/jcm8050707 ◽

2019 ◽

Vol 8 (5) ◽

pp. 707 ◽

Cited By ~ 10

Author(s):

Vincent Cuminetti ◽

Lorena Arranz

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Hematopoietic Stem Cell ◽

Stem Cell Niche ◽

Functional Responses ◽

Hematopoietic Stem ◽

Bone Marrow Adipocytes ◽

Hematopoietic Stem Cell Niche ◽

Cell Niche

Bone marrow adipocytes (BMA) exert pleiotropic roles beyond mere lipid storage and filling of bone marrow (BM) empty spaces, and we are only now beginning to understand their regulatory traits and versatility. BMA arise from the differentiation of BM mesenchymal stromal cells, but they seem to be a heterogeneous population with distinct metabolisms, lipid compositions, secretory properties and functional responses, depending on their location in the BM. BMA also show remarkable differences among species and between genders, they progressively replace the hematopoietic BM throughout aging, and play roles in a range of pathological conditions such as obesity, diabetes and anorexia. They are a crucial component of the BM microenvironment that regulates hematopoiesis, through mechanisms largely unknown. Previously considered as negative regulators of hematopoietic stem cell function, recent data demonstrate their positive support for hematopoietic stem cells depending on the experimental approach. Here, we further discuss current knowledge on the role of BMA in hematological malignancies. Early hints suggest that BMA may provide a suitable metabolic niche for the malignant growth of leukemic stem cells, and protect them from chemotherapy. Future in vivo functional work and improved isolation methods will enable determining the true essence of this elusive BM hematopoietic stem cell niche component, and confirm their roles in a range of diseases. This promising field may open new pathways for efficient therapeutic strategies to restore hematopoiesis, targeting BMA.

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Biomimetic reconstruction of the hematopoietic stem cell niche for in vitro amplification of human hematopoietic stem cells

PLoS ONE ◽

10.1371/journal.pone.0234638 ◽

2020 ◽

Vol 15 (6) ◽

pp. e0234638 ◽

Cited By ~ 1

Author(s):

L. Marx-Blümel ◽

C. Marx ◽

F. Weise ◽

J. Frey ◽

B. Perner ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Hematopoietic Stem Cells ◽

Hematopoietic Stem Cell ◽

Stem Cell Niche ◽

Hematopoietic Stem ◽

Hematopoietic Stem Cell Niche ◽

Cell Niche

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Closer to Nature: The Role of MSCs in Recreating the Microenvironment of the Hematopoietic Stem Cell Niche in vitro

Transfusion Medicine and Hemotherapy ◽

10.1159/000520932 ◽

2022 ◽

pp. 1-10

Author(s):

Patrick Wuchter ◽

Anke Diehlmann ◽

Harald Klüter

Keyword(s):

Bone Marrow ◽

Stem Cell ◽

Stem Cell Niche ◽

Model Systems ◽

Bone Marrow Niche ◽

Hematopoietic Stem ◽

Hematopoietic Stem Cell Niche ◽

Cell Niche

Background: The stem cell niche in human bone marrow provides scaffolds, cellular frameworks and essential soluble cues to support the stemness of hematopoietic stem and progenitor cells (HSPCs). To decipher this complex structure and the corresponding cellular interactions, a number of in vitro model systems have been developed. The cellular microenvironment is of key importance, and mesenchymal stromal cells (MSCs) represent one of the major cellular determinants of the niche. Regulation of the self-renewal and differentiation of HSPCs requires not only direct cellular contact and adhesion molecules, but also various cytokines and chemokines. The C-X-C chemokine receptor type 4/stromal cell-derived factor 1 axis plays a pivotal role in stem cell mobilization and homing. As we have learned in recent years, to realistically simulate the physiological in vivo situation, advanced model systems should be based on niche cells arranged in a three-dimensional (3D) structure. By providing a dynamic rather than static setup, microbioreactor systems offer a number of advantages. In addition, the role of low oxygen tension in the niche microenvironment and its impact on hematopoietic stem cells need to be taken into account and are discussed in this review. Summary: This review focuses on the role of MSCs as a part of the bone marrow niche, the interplay between MSCs and HSPCs and the most important regulatory factors that need to be considered when engineering artificial hematopoietic stem cell niche systems. Conclusion: Advanced 3D model systems using MSCs as niche cells and applying microbioreactor-based technology are capable of simulating the natural properties of the bone marrow niche more closely than ever before.

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