Showing papers on "Cellular differentiation published in 1980"

Induction of differentiation of the human promyelocytic leukemia cell line (HL-60) by retinoic acid.

Abstract: The HL-60 cell line, derived from a patient with acute promyelocytic leukemia, proliferates continuously in suspension culture and consists predominantly (greater than 90%) of promyelocytes. These cells can be induced to differentiate to morphologically and functionally mature granulocytes by incubation with a wide variety of compounds, including butyrate and hypoxanthine and polar planar compounds such as dimethyl sulfoxide and hexamethylene bisacetamide. We have now found that retinoic acid (all-trans-retinoic acid) induces differentiation (as measured morphologically and by the ability to reduce nitroblue tetrazolium) of HL-60 at concentrations as low as 1 nM. Maximal differentiation (approximately 90%) occurs at 1 micro M, a concentration 1/500th to 1/160,000th the concentrations of butyrate (0.5 mM) and dimethyl sulfoxide (160 mM) that promote a similar increase in differentiation. Continuous exposure to retinoic acid is necessary for optimal differentiation, with the percentage of mature cells in the culture directly related to the length of time of exposure to retinoic acid. Retinoic acid and 13-cis-retinoic acid are equally effective in inducing differentiation of HL-60. Retinol (vitamin A), retinal, and retinyl acetate are approximately 1/1000th less potent. This study suggests that retinoids could provide a therapeutic tool in the treatment of acute myeloid leukemia, a disease that has been looked upon as primarily involving a block in myeloid differentiation, and indicates that retinoids, in addition to their well-characterized involvement in epithelial cell differentiation, may also be involved in the differentiation of certain hematopoietic cells.

Discrete stages of human intrathymic differentiation: Analysis of normal thymocytes and leukemic lymphoblasts of T-cell lineage

Abstract: A series of monoclonal antibodies was used to define three discrete stages of human intrathymic T-cell differentiation The earliest stage was confined to <10% of thymocytes, which were·reactive with both OKT9 and OKT10 Subsequently, approximately 70% of human thymocytes acquired a thymocyte-restricted antigen, OKT6, lost OKT9 antigen, and expressed reactivity with OKT4 and OKT5 These last two monoclonal antibodies were previously shown to define inducer (helper) and cytotoxic/suppressor populations, respectively, in peripheral blood The OKT4+, OKT5+, OKT6+ “common” thymocyte population represents the majority of thymocytes and accounts for more than 70% of thymocytes With further maturation, thymocytes lose OKT6 reactivity, segregate into OKT4+ and OKT5+ subsets, and acquire reactivity with OKT3 (and OKT1) This latter stage corresponds to the more functionally mature subset The possible relationship of acute lymphoblastic leukemia of T-cell lineage to these proposed stages of intrathymic differentiation was determined Analysis of 25 tumor populations showed that 21 could be related to one or another differentiative stage The majority (15/21) were derived from an early thymocyte or prothymocyte subpopulation, 5/25 were derived from a common thymocyte subpopulation, and 1/25 was derived from a mature (OKT3+) subpopulation These data suggest that is it now possible to define stages of T-cell differentiation that can be related to T-cell malignancies in humans

Current concepts in immunology: Regulation of the immune response--inducer and suppressor T-lymphocyte subsets in human beings.

Abstract: HUMAN T lymphocytes are endowed with the capacity to recognize specific antigens, execute effector functions, and regulate the type and intensity of virtually all cellular and humoral immune responses.1 Two major functionally distinct subsets of T cells have been defined with heteroantiserums, autoantibodies, and monoclonal antibodies directed at stable cell-surface antigens.2 3 4 5 6 7 8 Both have been independently programmed for their respective inducer (helper) and cytotoxic/suppressor functions during intrathymic differentiation. This review focuses on the biology of human regulatory T-cell subpopulations in health and disease. Development of T Lymphocytes A thymic microenvironment is necessary for the differentiation of T cells in all species. . . .

Perisinusoidal Stellate Cells (Fat-Storing Cells, Interstitial Cells, Lipocytes), Their Related Structure in and around the Liver Sinusoids, and Vitamin A-Storing Cells in Extrahepatic Organs

Abstract: Publisher Summary This chapter discusses the history of the stellate cells. These cells are the integral elements of the wall of the sinusoids and that notion has introduced deep-rooted misconceptions in liver histology. The chapter discusses the morphological characteristics of stellate cells. The stellate cells are distributed only in the lobules of the liver and constitute 1.4% of parenchymal volume in the rat liver. They are stellate-shaped, are located in the space of Disse, and adhere to the sinusoidal wall. Their dendritic processes spread over the outer surface of the sinusoids and encircle the sinusoids or run longitudinally along them. Along the surface of these processes, a number of micropinocytotic vesicles or caveolae are observed. No basal lamina is discernible. The stellate cells are separated from the parenchymal cells by intercellular spaces of varying dimensions in which collagen bundles are often seen. The stellate cells in the liver of various mammals are morphologically classified into two types: in the first type, branching of the cytoplasmic processes is well developed many medium-sized lipid droplets are apparent; in the second type, cytoplasmic processes are not so conspicuous and one or two large lipid droplets are located in the vicinity of the nuclei.

New cell cycle compartments identified by multiparameter flow cytometry

Abstract: Simultaneous measurements of cellular DNA and RNA as well as estimates of the sensitivity of DNA in situ to denaturation by acid (which correlates with the degree of chromatin condensation) and cell ability to incorporate 5-bromodeoxyuridine (BUdR), performed on over 40 different cell systems enabled us to subclassify cells into 12 functionally distinct cell cycle compartments. Quiescent cells had low RNA values, DNA very sensitive to denaturation, and they did not incorporate BUdR. Although in most cell systems they had 2C DNA content (G1Q), quiescent cells with higher DNA values (SQ and G2Q) were also seen. The G1 phase of exponentially growing cells had two distinct compartments, A and B. G1 cells entered S phase only from the B compartment. An increase in RNA and a decrease in the sensitivity of DNA to acid denaturation beyond a specific level characterized the transition of cells from the A to B compartments. Since the G1A to G1B transition was not linear but exponential, it may be assumed that a non-deterministic event triggering cell progression into the cycle resides within G1A. Under adverse growth conditions the probability of a G1A to G1B transition decreased. Cells In G2 had DNA more sensitive to acid denaturation than S or G1 phase cells. Mitotic cells had the most condensed chromatin and their RNA content was twice that of G1A cells. Differentiated cells were characterized by 2C DNA (G1D) but, depending on the cell type, had varying RNA content and different degrees of chromatin condensation. A hitherto undescribed category of cells undergoing transition from quiescence to the cycle (or vice versa) was distinguished based on their intermediate values of RNA, sensitivity of DNA to acid denaturation and inability to incorporate BUdR at the rate characteristic for S cells. Depending on their DNA content (C) at the time of transition these cells could be classified as G1T (2C), ST (4>C>2) or G2T (4C).

Osteoclasts derived from haematopoietic stem cells

Abstract: The origins of the multinucleated osteoclast have been controversial, with osteogenic precursors and haematopoietic stem cells as candidates. Recent evidence for the latter is persuasive but circumstantial. We report here direct evidence obtained in radiation chimaeras from a natural cytoplasmic cell marker transmitted by the donated haematopoietic stem cell.

Phorbol ester-induced differentiation of chronic lymphocytic leukaemia cells.

Abstract: The croton oil-derived tumour-promoting agent 12-O-tetra-decanoyl-phorbol-13-acetate (TPA) exerts pleiotropic effects on the differentiation and proliferation of both normal and malignant animal and human cells in vitro. TPA is mitogenic in nanomolar concentrations to chicken embryo fibroblasts1 and human T lymphocytes2 and inhibits the terminal differentiation of various committed embryonic cells3,4 and mouse Friend erythroleukaemia5 or myeloid leukaemia6 cells. TPA induces a terminal cell differentiation in some murine7 and human7–11 myeloid leukaemia and histiocytic lymphoma cells12. We report here the effect of TPA on chronic lymphocytic leukaemia (CLL) biopsy cells in vitro. In four out of five CLL patients studied, TPA induced the appearance of 90–100% lymphoblastoid and plasmacytoid cells after 4 days of culture. Under the influence of TPA, 86–97% of the cells expressed with time increasing amounts of intracytoplasmic immunoglobulin (C-Ig) of the same phenotype as that detected on the surface (S-Ig) of fresh, non-induced CLL cells. A parallel decrease in both monoclonal S-Ig density and DN A synthesis of the CLL cells was observed. Electron microscopic studies showed a maturation towards plasma cells. We therefore conclude that TPA is capable of inducing differentiation of CLL cells in vitro.

Stromal mechanisms of bone marrow: cloning in vitro and retransplantation in vivo.

Abstract: Since the existence of hemopoietic stem cells has been proved experimentally and these cells together with their descendants were found to spread within the hemopoietic system and to form colonies in hemopoietic organs [24], another challenging problem came to light, i.e. the problem of differentiation factors in hemopoiesis. The development of hemopoietic cells is believed to be regulated by local differentiation factors distributed among various hemopoietic organs. They produce a short-distance effect upon hemopoietic cells which largely accounts for different cellular content in various hemopoietic organs. The effect of local differentiation factors is manifested, in particular, during formation of hemopoietic colonies in irradiated recipient-mice. A typical feature of the colonies is high homogeneity of their cellular content as compared to the normal hemopoietic tissue [24]. Morphologically discernible cells of essentially the same type are found in the colonies by the 7–10th day. At the same time the colonies are shown to have polypotent stem cells and committed precursors for all the three types of hemopoiesis, as well as B cell precursors [15, 21]. Hence, for example, the development of myeloid precursors (regardless of the degree of their committment) is inhibited while they are still included in the erythroid colonies whereas the development of erythroid precursors is suppressed in the myeloid colonies.

Cellular metaplasia or transdifferentiation as a model for retinal cell differentiation.

Abstract: Publisher Summary This chapter discusses the possible mechanisms of transdifferentiation or cellular metaplasia as a model for studying the programming of differentiation in neural and other cells at the cellular and molecular levels. Vertebrate eye tissues are characterized by a unique ability to perform extensive tissue metaplasia and to convert their specificities during regeneration in situ, after the removal of particular tissues. Studies on such instability in differentiation have now been extended to the cellular level by means of cell culture experiments. Besides the pigmented epithelial cells of the retina, cells from the neural retina (NR) of a number of vertebrate species can also extensively transdifferentiate into lens and pigment cells under conditions of cell culture. All the literature since 1975, when the phenomenon was first announced, has been reviewed in the chapter. Transdifferentiation in vitro is a sequential process starting from NR cells and terminating with lens cells, either through the differentiation of pigment cells or not. Several intrinsic and external factors affecting transdifferentiation have been described along with the molecular events observed in the process. There are a number of reasons, although they are not absolutely convincing, as to why transdifferentiation can be a regulatory change not mainly due to a selective outgrowth of mutated cells or a small subpopulation of cells programmed toward only lens or pigment cells.

Microtubule-associated proteins: a monoclonal antibody to MAP2 binds to differentiated neurons.

Abstract: Hybridomas that secret IgG reacting specifically with the brain microtubule-associated protein MAP2 have been prepared with speen cells from BALB/c mice hyperimmunized with high molecular weight neurotubule-associated proteins. Immunofluorecence microscopy using dual fluorochrome labeling of tubulin and MAP2 antigens revealed identical patterns of interphase fiber networks in cells from explants of newborn mouse brain. The anti-MAP2 antibody did not stain primary mouse kidney cells or CHO, 3T3, HeLa, or PtK1 cell lines. Immunoprecipitation and antibody gel staining techniques failed to demonstrate any crossreacting antigen in these cells. MAP2 antigen was not seen in association with the mitotic spindle in any of the cells examined. Radioimmunoassay showed species crossreactivity of the anti-MAP2 antibody with mammalian but not avian neural cell extracts. Glial cells and some neuroblastoma cell lines did not appear to contain MAP2. However, in the B104 rat neuroblastoma cell line the MAP2 antigen appeared to be associated with the cytoskeleton concomitant with differentiation induced by dibutyryl cyclic AMP. In disagreement with most previously published reports, our data suggest that MAP2 is found only in differentiated neuronal cells and raises the possibility that MAP2 is involved in neuronal differentiation or neuron-specific processes.

Epidermal growth factor and expression of specific genes: effects on cultured rat pituitary cells are dissociable from the mitogenic response.

Abstract: Cultured rat pituitary tumor cells, GH3/D6, which synthesize both growth hormone and prolactin, have cell-surface epidermal growth factor (EGF) receptor sites (34,000 per cell) that bind 125I-labeled EGF with a high affinity (Kd approximately 1 nM). Prolonged treatment of the cells with EGF did not stimulate cell division but did inhibit thyroid hormone-stimulated cell growth. In addition, EGF altered the morphology of the cells from a rounded to an elongated conformation. EGF also induced a perturbation of chromatin structure in GH3 cell nuclei that was detected by an increase (40%) in the number of rifampicin-resistant initiation sites for bacterial RNA polymerase. This was accompanied by an increased synthesis of prolactin and an inhibition of synthesis of growth hormone. In the presence of EGF, the synthesis of growth hormone was no longer inducible by thyroid hormone, but it remained responsive to glucocorticoids. The results demonstrate that EGF can elicit major effects on the cellular phenotype and expression of specific genes in the absence of a proliferative response. This suggests that EGF can also regulate differentiated cellular functions.

"Transdifferentiation" of C6 glial cells in culture

Abstract: The activities of cyclic nucleotide phosphohydrolase, an enzyme marker for oligodendrocytes, and glutamine synthetase, an enzyme marker for astrocytes, were studied at early (21 to 26) and late (82 to 88) cell passages. The activity of cyclic nucleotide phosphohydrolase was markedly high and that of glutamine synthetase was low in the early passages, but this relation was reversed in the late passages. These findings suggest a "transdifferentiation" of C6 glial cells with passage in culture.

Constitutive uncoupling of pathways of gene expression that control growth and differentiation in myeloid leukemia: a model for the origin and progression of malignancy.

Abstract: Chemical carcinogens and tumor promoters have pleiotropic effects. Tumor initiators can produce a variety of mutations and tumor promotres can regulate a variety of physiological molecles that control growth and differentiation. The appropriate mutation and the regulation of the appropriate molecules to induce cell growth can initiate and promote the sequence of changes required for transformation of normal cells into malignant cells. After this sequence of changes, some tumors can still be induced to revert with a high frequency from a malignant phenotype to a nonmalignant phenotype. Results obtained from analysis of regulation of growth and differentiation in normal and leukemic myeloid cells, the phenotypic reversion of malignancy by induction of normal differentiation in myeloid leukemia, and the blocks in differentiation-defective leukemic cell mutants have been used to propose a general model for the origin and progression of malignancy. The model states that malignancy originates by changing specific pathways of gene expresion required for growth from inducible to constitutive in cells that can still be induced to differentiate normally by the physiological inducer of differentiation. The malignant cells, unlike the normal cells, then no longer require the physiological inducer for growth. This changes the requirements for growth and uncouples growth from differentiation. Constitutive expression of other specific pathways can uncouple other controls, which then causes blocks in differentiation and the further progression of malignancy. The existence of specific constitutive pathways of gene expression that uncouple controls in malignant cells can also exlain the expresion of fetal proteins, hormones, and some other specialized products of normal development in various types of tumors.

Embryonic-fetal erythroid characteristics of a human leukemic cell line

Abstract: We have studied a number of cell surface, enzyme, and protein markers in the human leukemic K562 cell line. We have confirmed previous observations that these cells accumulate human embryonic hemoglobins after exposure to hemin. In addition, our results demonstrated that these cells possess in the "ininduced" state i surface antigen, lactate dehydrogenase isoenzymes characteristic of embryonic or fetal erythroid cells, fetal and embryonic globin chains, and globin mRNAs. The levels if i antigen, embryonic globin chains, and embryonic globin mRNA increased substantially after exposure of the cells to hemin in suspension culture. In contrast, K562 cells lacked several surface, enzymatic, and functional properties typical of granulocytes, lymphocytes, monocytes, or adult erythroblasts, including HLA surface antigens, surface immunoglobulins, sheep erythrocyte rosetting, phagocytosis, terminal deoxynucleotidyl transferase, carbonic anhydrase, ABO and Rh blood groups, and adult hemoglobins. The K562 cell line therefore exhibits phenotypic properties of embryonic erythroid progenitor cells and a quantitative increase in the expression of some of these properties can be achieved by exposure of the cells to hemin.

Morphological characterization of nitrosourea-induced glioma cell lines and clones.

Abstract: A morphological characterization of cell lines and clones derived from nitrosourea-induced gliomas in CDF rats was performed and compared with normal rat glial cells. The glioma cell lines and clones proved to be morphologically stable. They retained individual characteristics and their state of differentiation despite repeated propagations in vitro. There are no indications suggesting that different cell types are transformed to a common phenotype. Different glioma cell lines maintain their individual morphological distinctiveness, however, normal glial cells give consistent morphological features and growth patterns irrespective of the variation of animal resource and passage level. The criss-cross or streaming cellular alignment and the multilayeredness make glioma cultures morphologically distinguishable from normal glial cultures which are characterized by monolayered epithelioid configuration. Furthermore, an elevated mitotic index and an increased nuclear-cytoplasmic ratio are observed consistently with glioma cells in culture, irrespective of the degree of anaplasia. Differentiated glioma cells preserve certain normal traits of glial components (i.e. morphological differentiation, cytoskeletal elaboration, etc.), yet express various neoplastic phenotypes (i.e., autonomous growth behaviors, tumorigenicity upon transplantation, etc.), though to a lesser extent than glioma cells of anaplastic variety. Despite the intimate interdigitations between apposed plasmalemmae of adjacent tumor cells, no recognizable intercellular junctional devices are present. The in vitro glioma cell system may serve as an excellent model for investigating the mechanisms for autonomous biological behavior and proliferation of neoplastic cells and for therapeutic screening.

T-cell specificity for H-2 and Ir gene phenotype correlates with the phenotype of thymic antigen-presenting cells.

Abstract: Experiments with chimaeric animals have demonstrated that the H-2 restriction specificity and immune response (Ir) gene phenotype of the T cell is acquired during development in the thymus. The mechanism by which this process occurs is unclear. One level of obligate expression of H-2 and Ir gene products is on the surface of antigen-presenting cells (APCs) which come from bone marrow precursors. We have now examined the turnover of APCs in the thymuses of F1 leads to parent (P) radiation-induced bone marrow chimaeras and found that APCs of donor phenotype appear at about 2 months after reconstitution. If the peripheral T-cell population is depleted after this time, new T cells emerging from the parental thymus (containing F1 APCs) behaving like F1 T cells, suggesting that cells from the bone marrow can influence thymic-directed T-cell differentiation. The thymic APC is an attractive condidate to play such a part in the development of the T-cell repertoire.

Clonal analysis of proliferation and differentiation of paired daughter cells: action of granulocyte-macrophage colony-stimulating factor on granulocyte-macrophage precursors.

Abstract: Mouse granulocyte-macrophage progenitor cells were stimulated to divide by the granulocyte-macrophage colony-stimulating factor (GM-CSF). The two daughter cells were separated; one daughter was transferred to medium containing a high concentration of GM-CSF, the other to medium containing a low concentration. Daughter cell-derived clones in the presence of 2500 units of GM-CSF had average cell cycle times 3.5 +/- 2.5 (SEM) hr shorter than clones derived from the paired daughter cell stimulated by 50 units of GM-CSF. Final colony size achieved after stimulation by 50 units of GM-CSF was always smaller than that of colonies stimulated by 2500 units of GM-CSF. In 8 of 41 instances, colonies stimulated by 50 units of GM-CSF developed, or were composed only of, macrophage populations in contrast to the granulocytic composition of colonies derived from the paired daughter cell growing in the presence of 2500 units of GM-CSF. The regulator GM-CSF appears able to directly influence cell cycle times and the pathway of differentiation entered by many bipotential granulocyte-macrophage precursor cells.