scholarly journals A Substrate-Mimicking Basement Membrane Drives the Organization of Human Mesenchymal Stromal Cells and Endothelial Cells Into Perivascular Niche-Like Structures

2021 ◽  
Vol 9 ◽  
Author(s):  
Valeria Perugini ◽  
Matteo Santin
Keyword(s):  
Bone Marrow ◽  
Tissue Culture ◽  
Endothelial Cells ◽  
Stem Cell ◽  
Stromal Cells ◽  
Stem Cell Niche ◽  
Tissue Culture Plastic ◽  
Histological Features ◽  
Cell Niche ◽  
3D Spheroids

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.

scholarly journals The identification of fibrosis-driving myofibroblast precursors reveals new therapeutic avenues in myelofibrosis

Blood ◽  
2018 ◽  
Vol 131 (19) ◽  
pp. 2111-2119 ◽  
Author(s):  
Rafael Kramann ◽  
Rebekka K. Schneider
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Stromal Cells ◽  
Stem Cell Niche ◽  
Solid Organ ◽  
Hematopoietic Stem ◽  
Gli Proteins ◽  
Hematopoietic Stem Cell Niche ◽  
Cell Niche ◽  
Organ Fibrosis

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.

Microenvironmental Cross-Talk of Wnt/Notch Signal in Hematopoietic Stem Cell

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3569-3569
Author(s):  
Jin-A Kim ◽  
Young-Ju Kang ◽  
Kyung-Sin Park ◽  
Eek-Hoon Jho ◽  
Il-Hoan Oh
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Stromal Cells ◽  
Stem Cell Niche ◽  
Bone Marrow Cells ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Notch Signal ◽  
Cell Niche ◽  
Notch Ligands

Abstract Microenvironment in the stem cell niche plays an important role to regulate self-renewal and differentiation of hematopoietic stem cells (HSCs). We previously showed opposing effects of b-catenin activation on HSC depending on target of activation in the bone marrow microenvironment. To further analyze the microenvironmental regulation of HSC by Wnt/b-catenin signal, we examined b-catenin activation mode in the trabecular bone marrows. In-situ immunohistochemistry of bone marrows revealed a compartmentalized enrichment of b-catenin in the spindle shaped, CD45(−) endosteal stroma of bone marrow (SNO cells) compared to CD45(+) hematopoietic cells. Receptors for canonical Wnt signals (Fz1, 2, 7, 8) or co-receptors (LRP5, 6) were also enriched in the CD45(−) mesenchymal stromal cells of bone marrows than hemapoietic cells. Moreover, accumulation of active form b-catenin was selectively observed in the “stimulated” bone marrows that had been irradiated or injected with Wnt 3a conditioned medium (Wnt 3a-CM), but not in the “steady state” bone marrows. To examine the effect of b-catenin activated stroma on HSCs, 5-FU bone marrow cells were co-cultured in-vitro for 5 days and transplanted into irradiated mice. A 3-fold higher expansion of primitive phenotype (Lin-Sca-1+c-kit+) cells were seen after culture without differences in cell cycle progression. Further, CRU analysis of the transplanted co-cultured cells displayed higher numbers of CRUs regenerated in the recipient bone marrows (65 CRU vs. 1155 CRUs for MIG vs. b-catenin MSC group, respectively). To directly test the effect of b-catenin activated stroma on HSC during normal reconstitution process, we compared HSC self-renewal in the marrows reconstituted with control or b-catenin activated MSCs; MIG or b-catenin transduced MSCs were directly injected into femur with bone marrow cells and each group mice marrows were then mixed (1:1) transplanted into secondary recipient mice for competitive CRU assay. A 3-fold higher CRU frequency was seen for the HSCs derived from marrows reconstituted with b-catenin/MSCs, indicating the physiological significance of b-catenin activation for in-vivo reconstitution. We next investigated the underlying mechanism for stromal b-catenin effects on HSCs. Expression analysis of b-catenin transduced or Wnt3a-stimulated MSCs revealed higher levels of notch ligands (jagged-1, dll-1), which was similarly observed in the trabecular endosteum of mice treated with Wnt3a-CM. A microarray-based expression analysis further supported up-regulation of notch ligands in b-catenin transduced MSCs, as evidenced by induction of dlk-1 and microfibrillar glycoprotein-2, a protein facilitating utilization of jagged-1. Importantly, induction of notch down-stream molecules (Hes-1 and Deltex-1) was demonstrated in the hematopoietic cells (Lin-Sca-1+) cells co-cultured on the b-catenin activated MSCs. Furthermore, enhancing effects of b-catenin/MSC for expanding undifferentiated cells were abrogated by treatment of gamma-secretase 2 inhibitors during the co-culture. These results show that b-catenin activated stromal cells activate notch signal in the contacting HSCs and that activated notch signal underlies the observed stimulatory effects of b-catenin activated stroma on HSCs. Taken together, Wnt/β-catenin activated stroma and the cross-talk with HSCs may function as a physiologically regulated microenvironmental cue for HSC self-renewal in the stem cell niche.

scholarly journals The hematopoietic stem cell niche in homeostasis and disease

Blood ◽  
2015 ◽  
Vol 126 (22) ◽  
pp. 2443-2451 ◽  
Author(s):  
Laura M. Calvi ◽  
Daniel C. Link
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Stromal Cells ◽  
Stem Cell Niche ◽  
Hematopoietic Progenitors ◽  
Hematopoietic Stem ◽  
Hematopoietic Malignancies ◽  
Hematopoietic Stem Cell Niche ◽  
Cell Niche ◽  
Stem Cell Niches

Abstract The bone marrow microenvironment contains a heterogeneous population of stromal cells organized into niches that support hematopoietic stem cells (HSCs) and other lineage-committed hematopoietic progenitors. The stem cell niche generates signals that regulate HSC self-renewal, quiescence, and differentiation. Here, we review recent studies that highlight the heterogeneity of the stromal cells that comprise stem cell niches and the complexity of the signals that they generate. We highlight emerging data that stem cell niches in the bone marrow are not static but instead are responsive to environmental stimuli. Finally, we review recent data showing that hematopoietic niches are altered in certain hematopoietic malignancies, and we discuss how these alterations might contribute to disease pathogenesis.

Disruption of Bis Leads to Deterioration of Mesenchymal Stromal Cells Predominantly Affecting Vascular Compartment of Hematopoietic Stem Cell Niche.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3627-3627
Author(s):  
Il-Hoan Oh ◽  
Kyong-Rim Kwon ◽  
Ji-Yeon Ahn ◽  
Myungshin Kim ◽  
Jeong-Hwa Lee
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Stem Cell Niche ◽  
Cellular Stress ◽  
Hematopoietic Stem ◽  
Stromal Component ◽  
Cell Niche ◽  
Vascular Compartment

Abstract Abstract 3627 Poster Board III-563 The stem cell niche plays an important role in the microenvironmental regulation of hematopoietic stem cells (HSCs), but the integration of niche activity remains poorly understood. In this study explored the hematopoietic defect of mice disrupted with Bis/BAG-3/CAIR-1, a protein related to apoptosis and response to cellular stress and show that functional loss of bis leads to series of hematopoietic derangements due to perturbation of vascular stem cell niche. First, mice with targeted disruption of bis (bis−/−) exhibited severe hypocellularity in the bone marrows and spleen starting from 16 days after birth. Affected mice exhibited loss of primitive neonatal HSCs (CD34+Lin-Sca-1+c-kit+) and defect in early stage B-lymphopoiesis including common lymphoid progenitors (IL-17R+LSK), pre-B and pro-B cell populations, but not for mature recycling B-lymphocytes (IgD+B220+). However, this hematological defect of bis−/− mice was not reproduced when bis−/− bone marrow cells were transplanted into wild-type (WT) recipients, pointing to the microenvironmental origin of the phenotypes. Subsequent analysis of bis−/− mice bone marrow revealed a characteristic defect in the mesenchymal stromal component that included a quantitative loss of stromal cells (CD45-CD31-TER119-CD105+) in the bone marrows and rapid sensescence of stromal cells comprising colony forming unit-fibroblast (CFU-F) when re-plated in the ex-vivo culture. Moreover, mesenchymal stromal cells expressing CXCL-12 or IL-7 was lost in the affected bone marrows with lowered density of vascular development, together indicating a perturbation of peri-vascular stem cell niche in the bone marrow. In contrast, no abnormalities were observed in the growth and hematopoietic supporting activities of osteoblasts obtained from bis−/− mice. Collectively, these results indicate that Bis functions to mediate cellular regulation of the stem cell niche activities selectively on the vascular compartment without affecting osteoblastic niche, and suggest that Bis may serve as a molecule that can bridge the microenvironment niche and cellular stress/apoptotic signals during the in-vivo orchestration of hematopoiesis. Disclosures: No relevant conflicts of interest to declare.

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