Wnt1 and BMP2: two factors recruiting multipotent neural crest progenitors isolated from adult bone marrow

Recent studies have shown that neural crest-derived progenitor cells can be found in diverse mammalian tissues including tissues that were not previously shown to contain neural crest derivatives, such as bone marrow. The identification of those "new" neural crest-derived progenitor cells opens new strategies for developing autologous cell replacement therapies in regenerative medicine. However, their potential use is still a challenge as only few neural crest-derived progenitor cells were found in those new accessible locations. In this study, we developed a protocol, based on wnt1 and BMP2 effects, to enrich neural crest-derived cells from adult bone marrow. Those two factors are known to maintain and stimulate the proliferation of embryonic neural crest stem cells, however, their effects have never been characterized on neural crest cells isolated from adult tissues. Using multiple strategies from microarray to 2D-DIGE proteomic analyses, we characterized those recruited neural crest-derived cells, defining their identity and their differentiating abilities.     

Expression and function of galectin-1 in adult neural stem cells

Neural stem cells (NSCs) in the adult mammalian brain proliferate and continuously produce new neurons. To date, there has been little research into the functions of lectins in adult NSCs. Recently, we reported that a lectin, galectin-1, is expressed on adult NSCs and promotes their proliferation through its carbohydrate-binding ability. This evidence raises the possibility that glycans play roles in the proliferation of adult NSCs. Received 6 November 2006; received after revision 13 December 2006; accepted 15 February 2007     

Coaxing bone marrow stromal mesenchymal stem cells towards neuronal differentiation: progress and uncertainties

Multipotent adult stem cells capable of developing into particular neuronal cell types have great potential for autologous cell replacement therapy for central nervous system neurodegenerative disorders and traumatic injury. Bone marrow-derived stromal mesenchymal stem cells (BMSCs) appear to be attractive starting materials. One question is whether BMSCs could be coaxed to differentiate in vitro along neuronal or glial lineages that would aid their functional integration post-transplantation, while reducing the risk of malignant transformation. Recent works suggest that BMSCs could indeed be differentiated in vitro to exhibit some cellular and physiological characteristics of neural cell lineages, but it is not likely to be achievable with simple chemical treatments. We discussed recent findings pertaining to efforts in neuronal differentiation of BMSCs in vitro, and results obtained when these were transplanted in vivo. Received 19 January 2006; received after revision 24 February 2006; accepted 12 April 2006     

Immune suppression by neutrophils and granulocytic myeloid-derived suppressor cells: similarities and differences

Neutrophils are essential effector cells in the host defense against invading pathogens. Recently, novel neutrophil functions have emerged in addition to their classical anti-microbial role. One of these functions is the suppression of T cell responses. In this respect, neutrophils share similarities with granulocytic myeloid-derived suppressor cells (G-MDSCs). In this review, we will discuss the similarities and differences between neutrophils and G-MDSCs. Various types of G-MDSCs have been described, ranging from immature to mature cells shaping the immune response by different immune suppressive mechanisms. However, all types of G-MDSCs share distinct features of neutrophils, such as surface markers and morphology. We propose that G-MDSCs are heterogeneous and represent novel phenotypes of neutrophils, capable of suppressing the immune response. In this review, we will attempt to clarify the differences and similarities between neutrophils and G-MDSCs and attempt to facilitate further research.     

Preparative separation of nucleated cells from human bone marrow

Summary A comparison has been made between the separation of nucleated cells from human bone marrow aspirates by high mol.wt polymers and the buffy coat techniques.Acknowledgment. This investigation was supported by grant DHEW 5R01 CA 19997-02, awarded by the National Cancer Institute.     

Haemopoietic stem cell concentration and CFUs in DNA synthesis in bone marrow from different bone regions

Summary The concentration of colony-forming cells (CFUs) is about 40% less in sternal marrow than in the marrow of lumbar vertebrae and femora. Marrow of trabecular bones in lumbar vertebrae contains fewer mitotically active CFUs than marrow of trabecular bones in the femoral distal epiphysis and metaphysis, or the peripheral marrow near the cortical bone in the femoral diaphysis. Only a minor part of the variability of the results in the CFU-assay is due to differences in CFU-concentrations between individual donor mice; pooling of the cell suspensions does not substantially decrease variability. Specific pathogen-free mice yield the same results as BALB/c mice from conventional breeding.Acknowledgments. This work was performed with support of Euratom contract No. 233-771 BIO B. We thank L. Tessens for his excellent technical assistance.     

mTOR signaling in neural stem cells: from basic biology to disease

The mammalian target of rapamycin (mTOR) pathway is a central controller of growth and homeostasis, and, as such, is implicated in disease states where growth is deregulated, namely cancer, metabolic diseases, and hamartoma syndromes like tuberous sclerosis complex (TSC). Accordingly, mTOR is also a pivotal regulator of the homeostasis of several distinct stem cell pools in which it finely tunes the balance between stem cell self-renewal and differentiation. mTOR hyperactivation in neural stem cells (NSCs) has been etiologically linked to the development of TSC-associated neurological lesions, such as brain hamartomas and benign tumors. Animal models generated by deletion of mTOR upstream regulators in different types of NSCs reproduce faithfully some of the TSC neurological alterations. Thus, mTOR dysregulation in NSCs seems to be responsible for the derangement of their homeostasis, thus leading to TSC development. Here we review recent advances in the molecular dissection of the mTOR cascade, its involvement in the maintenance of stem cell compartments, and in particular the implications of mTOR hyperactivation in NSCs in vivo and in vitro.     

Preparative separation of nucleated cells from human bone marrow.

A comparison has been made between the separation of nucleated cells from human bone marrow aspirates by high mol. wt polymers and the buffy coat techniques.     

Macrophages derived from bone marrow modulate differentiation of myeloid dendritic cells

Dendritic cells (DC) are specialized antigen-presenting cells. Bone marrow monocytes have been widely used to generate murine myeloid DC. We found that mouse macrophages derived from bone marrow CD11b⁺ monocytes influenced the differentiation of these precursors into DC. Modulation of differentiation was demonstrated by the down-regulation of CD11c, CD40, and CD86 expression and by IL-12 production. DC differentiated in the presence of conditioned medium from bone marrow-derived macrophage culture (MCM) had impaired ability to stimulate proliferation of, and IFN- γ production by, allogeneic CD4⁺ T cells. This inhibition of DC differentiation was mainly mediated by secretory products from macrophages but not by cell-cell contact. MCM contained higher concentrations of macrophage-colony-stimulating factor (M-CSF), IL-10, and TGF- β1, whereas IL-6 remained unchanged compared with conditioned medium from fresh monocytes. M-CSF may be the major mediator in MCM inhibiting DC differentiation. This study demonstrates an important influence of bone marrow-derived macrophages on DC precursors during DC differentiation. Received 12 September 2006; received after revision 20 October 2006; accepted 13 November 2006     

Cryoprotection of human bone marrow committed stem cells (CFU-c) by dextran,glycerol and dimethyl sulfoxide

Summary Dextran, glycerol and dimethyl sulfoxide (DMSO), alone or in combination, were used for cryoprotection of human bone marrow cells. The viability of cryopreserved cells was assessed by culture of myelopoiesis-committed stem cells (CFU-c) in vitro. A significantly better protection against freezing injury was obtained by 9% dextran in combination with 3 or 5% DMSO, and also with 5 or 10% DMSO alone, than with either 15% glycerol or 9% dextran with 1% DMSO.Acknowledgments. This work has been supported by the grant Nr. 140.AK-79 (5) from the Swiss Cancer League.     

Dissociated thymus and bone marrow cells: Synergism in Graft Versus Host reaction

Zusammenfassung Thymus- und Knochenmarkzellen von neonatalen Ratten wurden in letal bestrahlte Mäuse inoculiert. Thymus- oder Knochenmarkzellen allein erzeugten keine messbare immunologische Reaktion gegen den Wirt. Eine Kombination beider Zellarten verursachte jedoch eine GVH-Reaktion (Synergismus). Neben einer Schädigung durch zelluläre Immunreaktionen scheinen besonders die Wechselgewebe (erythropoetisches System etc.) des Wirtstieres auch auf humoralem Wege angegriffen zu werden.     

Abscence of chromosomes abnormalities and acute leukemia : relationships with normal bone marrow cells

The absence of chromosome abnormalities in 50% of human acute leukemias stress the significance of cytogenetic abnormalities in malignancies. Karyotypically normal cells from acute leukemias were shown to be non leukemic cells by cytological and cytogenetic comparisons. Chromosomally normal acute promyelocytic leukemias could be explained by differences between proliferation rates of bone marrow cells and by bias when choosing metaphases to be analysed. The role of chromosomal abnormalities in acute leukemia must be therefore questioned from a new definition of cytogenetic methods.