Showing papers on "Stem cell marker published in 1998"

A newly discovered class of human hematopoietic cells with SCID-repopulating activity

Abstract: The detection of primitive hematopoietic cells based on repopulation of immune-deficient mice is a powerful tool to characterize the human stem-cell compartment. Here, we identify a newly discovered human repopulating cell, distinct from previously identified repopulating cells, that initiates multilineage hematopoiesis in NOD/SCID mice. We call such cells CD34neg-SCID repopulating cells, or CD34neg-SRC. CD34neg-SRC are restricted to a Lin-CD34-CD38- population without detectable surface markers for multiple lineages and CD38 or those previously associated with stem cells (HLA-DR, Thy-1 and CD34). In contrast to CD34+ subfractions, Lin-CD34-CD38- cells have low clonogenicity in short-and long-term in vitro assays. The number of CD34neg-SRC increased in short-term suspension cultures in conditions that did not maintain SRC derived from CD34+ populations, providing independent biological evidence of their distinctiveness. The identification of this newly discovered cell demonstrates complexity of the organization of the human stem-cell compartment and has important implications for clinical applications involving stem-cell transplantation.

Extra-insular beta cells associated with ductules are frequent in adult human pancreas.

Abstract: Routine immunohistochemical analysis of human donor pancreata indicated the frequent occurrence of single insulin-immunoreactive cells. In a quantitative analysis of nine organs consecutively recruited from adult donors, 15 percent of all beta cells were found in units with a diameter less than < 20 μm and without associated glucagon-, somatostatin-, or pancreatic polypeptide cells. These single beta-cell units are located in or along ductules, from which they appear to bud as previously noticed in fetal and neonatal organs. They contain significantly smaller beta cells than endocrine aggregates with a larger diameter. The use of ductal cell markers such as cytokeratin 19, carbonic anhydrase-II and carbohydrate antigen 19.9 identified a close topographical association between ductal cells and budding beta cells; it also indicated that pancreatic lobules are composed of nearly one third ductal cells. The presence of Ki67 proliferation marker-immunoreactive ductal cells (0.05 %) and absence of Ki67-immunoreactive budding beta cells is compatible with the view that beta-cell neogenesis depends on ductal cell proliferation and differentiation. The high proportion of budding beta cells in the adult human pancreas suggests the presence of numerous loci with a potential for beta-cell neogenesis. [Diabetologia (1998) 41: 629–633]

Properties and uses of embryonic stem cells: prospects for application to human biology and gene therapy

Abstract: Embryonic stem cells are pluripotent cells derived from the early mouse embryo that can be propagated stably in the undifferentiated state in vitro. They retain the ability to differentiate into all cell types found in an embryonic and adult mouse in vivo, and can be induced to differentiate into many cell types in vitro. Exploitation of ES cell technology for the creation of mice bearing predetermined genetic alterations has received widespread attention because of the sophistication that it brings to the study of gene function in mammals. Analysis of cell differentiation in vitro has also been of value, leading to the identification of novel bioactive factors and the elucidation of cell specification mechanisms. In this paper, we summarise the features of pluripotent cell lines and their applications, foreshadowing the impact that these systems may have on human biology. While the isolation of definitive human pluripotent cell lines has not yet been achieved, potential applications for these cells in the study of human biology, particularly cell specification, can be envisaged. Of particular interest is the possibility that human embryonic stem cells with properties similar to mouse embryonic stem cells might provide a generic system for gene therapy.

Culture of adult human islet preparations with hepatocyte growth factor and 804G matrix is mitogenic for duct cells but not for beta-cells

Abstract: It has recently been reported that human adult β-cells proliferate during culture on an extracellular matrix prepared from rat 804G cells and in the presence of hepatocyte growth factor (HGF) (6). The present study compares the mitogenic effect of this condition on human β-cells and on neighboring non-endocrine duct cells. Islet cell-enriched fractions were prepared from adult human organ donors and cultured in suspension or on 804G matrix, with or without HGF. The combination of 804G matrix and HGF increased the number of 5-bromo-2'-deoxyuridine-positive (BrdU+) cells within 48 h reaching a maximum after 4 days. In sections, virtually all BrdU+ cells were negative for insulin or glucagon and for preproinsulin mRNA but expressed the ductal cell markers cytokeratin 19 and 7, carbonic anhydrase-II, and carbohydrate antigen 19-9. After 4 days of culture, the cytokeratin 19+ ductal cells exhibited a BrdU-labeling index of 30% ( P < 0.01 vs. 2% without HGF and matrix), whereas <0.1% of insulin-positive and <1% of glucagonpositive cells were labeled. Formation of bilayers with ductal cells covering the endocrine cells may cause erroneous interpretation on double positivity in unsectioned tissue. It is concluded that culture of human islet cell preparations with HGF and 804G matrix stimulates the proliferation of the duct cells but not of the underlying β-cells.

Differentiation of human pluripotent teratocarcinoma stem cells induced by bone morphogenetic protein-2.

Abstract: Pluripotent human teratocarcinoma stem cells cultured in vitro provide a resource for the study of early embryonic development in man, as well as a means for discovery of novel factors controlling cell differentiation and commitment We previously reported that the human teratocarcinoma stem cell line GCT 27X-1 could be induced to differentiate into an endodermal progenitor cell by treatment with high doses of retinoic acid A search for polypeptide inducers of differentiation in this system has identified bone morphogenetic protein-2 (BMP-2) as a potent inducer of differentiation In cell line GCT 27X-1, treatment with BMP-2 reduces proliferation, induces morphological changes similar to obtained following treatment with retinoic acid, and causes a decrease in the expression of transcripts for the stem cell markers CD30 and Oct-4 Preliminary immunochemical studies indicate that the differentiated cells produced by BMP-2 are endodermal precursors with a pattern of marker expression similar to that found in retinoic acid treated cells Models of endoderm differentiation in humans will be useful for identifying the molecules which mediate cell interactions in development, and in achieving directed differentiation of cells for use in transplantation

Molecular marker for muscle stem cells

Abstract: In accordance with the invention, Bcl-2 expression is a molecular marker for muscle stem cells. Thus, the invention provides methods for identifying and isolating muscle stem cells. In addition, the invention provides methods for determining whether a test compound modulates muscle stem cell differentiation and/or proliferation. Finally, the invention provides methods for expressing an exogenous coding sequence in a muscle stem cell.

Neoplastic thymic epithelial cells of human thymoma support T cell development from CD4−CD8− cells to CD4+CD8+ cells in vitro

Abstract: Human thymoma is a thymic epithelial cell tumour which often contains a large number of immature T cells and is frequently associated with autoimmune diseases. Since thymic epithelial cells play key roles in the development and selection of T cells in the normal thymus, we hypothesized that the neoplastic thymic epithelial cells of thymoma may support T cell differentiation in the tumour. We characterized CD4-CD8- cells in thymoma and applied an in vitro reconstitution culture system using the CD4-CD8- cells and the neoplastic epithelial cells isolated from thymoma. CD34, a stem cell marker, was expressed on 29.9 +/- 12.2% of CD4-CD8- cells in thymoma. TCRgammadelta was expressed on 27.4 +/- 15.1% of CD4-CD8- cells and CD19, a B cell marker, was expressed on 14.1 +/- 23.1% of CD4-CD8- cells. CD4-CD8- cells expressed both IL-7R alpha-chain and common gamma-chain. Purified CD4-CD8- cells from thymomas were cultured with the neoplastic epithelial cells, and their differentiation into CD4+CD8+ cells via CD4 single-positive intermediates was observed within 9 days' co-culture in the presence of recombinant IL-7. Furthermore, we examined the reconstitution culture using CD34+CD4-CD8- cells purified from normal infant thymus. The CD34+CD4-CD8- cells in normal thymus also differentiated to CD4+CD8+ cells in the allogeneic co-culture with the neoplastic epithelial cells of thymoma. These results indicate that the tumour cells of thymoma retain the function of thymic epithelial cells and can induce differentiation of T cells in thymoma.

Hematopoietic stem cells

Abstract: The present invention relates to human hemotopoietic stem cells characterized as CD34-Lin- and CD34-CD38-Lin- and to methods of isolating and using such cells in compositions and in methods for the reconstitution of a deficient or missing cell population. The present invention also provides a population of human hematopoietic stem cells that can be isolated and genetically altered for introduction in a human patient, to correct various genetic disorders and cultured and further differentiated in vitro to provide a new population of cells.

A process to study changes in gene expression in stem cells

Abstract: The present invention includes a method to identify stem cell genes that are differentially expressed in stem cells at various stages of differentiation when compared to undifferentiated stem cells by preparing a gene expression profile of a stem cell population and comparing the profile to a profile prepared from stem cells at different stages of differentiation, thereby identifying cDNA species, and therefore genes, which are expressed. The present invention also includes methods to identify a therapeutic agent that modulates the expression of at least one stem cell gene associated with the differentiation, proliferation and/or survival of stem cells.

Use of multipotent neural stem cell progeny to augment non-neural tissues

Abstract: Multipotent neural stem cell (MNSC) progeny are transplanted into a recipient wherein they augment host tissue. The stem cells have a universal lineage potential and are capable of producing progeny that, in response to appropriate environmental signals, can differentiate into a variety of differentiated cell types, and not just neural lineages. MNSCs can be proliferated ex vivo to provide an unlimited supply of stem cells and stem cell progeny which give rise to the differentiated cell types of various tissues. The stem cells are readily amenable to genetic modification, if desired. They also have the advantage that they can be obtained from autologous adult human tissue and thus overcome prior art problems of transplant rejections.

Developmental variation in stem-cell markers from human fetal liver and umbilical cord blood leukocytes.

Abstract: Fetal tissues containing haematopoietic stem cells (HSC) are of potential value for allogeneic transplantation and gene therapy. Flow cytometry was used to investigate CD34+ cells from human fetal livers and umbilical cord (placental) blood (UCB). CD34+ cells, expressed as a proportion of CD45-positive leukocytes, were much more abundant in fetal livers (mean 38%) than in UCB (mean 0.3%), but fetal liver cells had lower proportions of CD34+HLA-DR+ and CD34+ CD38+ subsets. In fetal liver, there was a strong and highly significant inverse correlation between CD34+ cells (as a proportion of total leukocytes) and gestational age; no such relationship was found for subsets of CD34+ cells coexpressing CD38 or CDw90 (Thy-1), but CD34+HLA-DR+ cells were less abundant in first- compared to second-trimester livers. In UCB, a trend towards decreasing CD34+ cells (as a proportion of total leukocytes) with increasing gestational age in late pregnancy was also observed. The composition of fetal leukocytes changes during development, and therefore the timing of fetal HSC harvesting could be of relevance to transplantation outcome.

Analysis of hematopoietic stem cell reprogramming with toxigenicity

Abstract: The molecular mechanisms by which a stem cell is committed to individual lineage are largely unknown. Two different models, though not mutually exclusive, are currently debated. The first describes the temporal and hierarchical coordination of lineage-specific transcriptional programs. The second suggests that multilineage genes are expressed in a self-renewing and undifferentiated cell prior to lineage commitment. To challenge these two models in in vivo-appropriate conditions, the expression of an exogenous toxigene was used to create transgenic animals in which an inducible, reversible cell knock-out at a specific stage of differentiation could be achieved. Both additional transgenesis using the megakaryocyte specific alphaIIb promoter and targeted transgenesis were used to express the herpes virus thymidine kinase (tk) gene in the megakaryocytic lineage. When the tk gene was targeted to the locus of the megakaryocyte-specific alphaIIb gene, a typical Glanzman thrombasthenic syndrome was created. Despite this bleeding disorder, the lack of expression of the alphaIIb gene did not affect the development of the mice. In both transgenic and targeted animals, all progenitor cells were sensitive to the effect of the gancyclovir (GCV), both in vivo and ex vivo. Long-term bone marrow cell cultures on stromal layers indicated that most of the very early progenitor cells expressed the enzyme. All the results obtained with this inducible toxic phenotype indicated that genetic programs that are in control of the expression of lineage-specific genes are operative in a totipotent stem cell prior to lineage commitment and strongly support the concept that stem cells express a multilineage transcriptome.