SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The study of cell lineages has been, and remains, of crucial importance in developmental biology. It requires the identification of a cell or group of cells and of all of their descendants during embryonic development. Here, we provide a brief survey of how different techniques for achieving this have evolved over the last 100 years.
Osteoclasts are multinucleated cells of hemopoietic origin that are responsible for bone resorption during physiological bone remodeling and in a variety of bone diseases. Osteoclast development requires direct heterotypic cell-cell interactions of the hemopoietic osteoclast precursors with the neighboring osteoblast/stromal cells. However, the molecular mechanisms underlying these heterotypic interactions are poorly understood. We isolated cadherin-6 isoform, denoted cadherin-6/2 from a cDNA library of human osteoclast-like cells. The isolated cadherin-6/2 is 3,423 bp in size consisting of an open reading frame of 2,115 bp, which encodes 705 amino acids. This isoform lacks 85 amino acids between positions 333 and 418 and contains 9 different amino acids in the extracellular domain compared with the previously described cadherin-6. The human osteoclast-like cells also expressed another isoform denoted cadherin-6/1 together with the cadherin-6. Introduction of cadherin-6/2 into L-cells that showed no cell-cell contact caused evident morphological changes accompanied with tight cell-cell association, indicating the cadherin-6/2 we isolated here is functional. Moreover, expression of dominant-negative or antisense cadherin-6/2 construct in bone marrow-derived mouse stromal ST2 cells, which express only cadherin-6/2, markedly impaired their ability to support osteoclast formation in a mouse coculture model of osteoclastogenesis. Our results suggest that cadherin-6 may be a contributory molecule to the heterotypic interactions between the hemopoietic osteoclast cell lineage and osteoblast/bone marrow stromal cells required for the osteoclast differentiation. Since both osteoclasts and osteoblasts/bone marrow stromal cells are the primary cells controlling physiological bone remodeling, expression of cadherin-6 isoforms in these two cell types of different origin suggests a critical role of these molecules in the relationship of osteoclast precursors and cells of osteoblastic lineage within the bone microenvironment.
Trophoblast cell lineage is established through the first cellular differentiation in mammalian embryogenesis, and its developmental potential is restricted to the extraembryonic tissues contributing solely to the placenta. Several lines of evidence suggest a relative lack of importance of DNA methylation in gene regulation in the extraembryonic tissues when compared with embryonic ones. Here we analyzed the dynamics of epigenetic status in the upstream region of mouse Ddah2 gene, which was found to be specifically repressed in a stem cell population of trophoblast cell lineage. We found a tissue-dependent differentially methylated region in the regulatory region of the Ddah2 gene. This region was hypermethylated in trophoblast stem cells and was hypomethylated in differentiated cells both in vivo and in vitro. This change was well correlated with Ddah2 expression. In addition, in vitro methylation confined to the differentially methylated region was sufficient to repress promoter activity in the reporter assay. Furthermore, a repressive pattern of histone modifications was formed around the differentially methylated region in undifferentiated trophoblast stem cells with repressed Ddah2. Our data suggest that DNA methylation-mediated chromatin remodeling is involved in the regulation of the Ddah2 gene expression and thus is important even in trophoblast cell lineage.
BACKGROUND/AIMS: Evidence that bone marrow cells have trans-differentiating potential to hepatocytes has been described in recent reports. However, the molecular mechanism underlying this phenomenon is unclear. To address this issue, we investigated the parameters involved in the trans-differentiation of bone marrow cells into a hepatic lineage. METHODS: Mouse BM cells were cultured in a collagen gel without or with growth factors including basic fibroblast growth factor. The expression of hepatocyte-specific markers, cholangiocyte-specific marker and liver-enriched transcription factors was identified by RT-PCR and immunohistochemistry. RESULTS: Basic fibroblast growth factor was found to be the most effective for inducing albumin in cultured BM cells. Furthermore, on stimulation of basic fibroblast growth factor, BM cells were found to express other hepatocyte-specific markers and a cholangiocyte-specific marker. This conversion was found to be associated with the induction of transcription factors including hepatocyte nuclear factors and GATA family proteins. CONCLUSIONS: We established an in vitro culture system in which mouse bone marrow cells could trans-differentiate to hepatic lineage cells in response to growth factors, without cell fusion. In particular, basic fibroblast growth factor has the ability to induce the trans-differentiation into hepatic lineage cells from BM cells.
The cells of hematopoietic and vascular endothelial cell lineages are believed to share a common precursor, termed hemangioblast. However, the existence of a growth factor acting relatively specifically on hemangioblasts remains unclear. Here we report the identification of hemangiopoietin (HAPO), a novel growth factor acting on both hematopoietic and endothelial cell lineages. In vitro in the human system, recombinant human HAPO (rhHAPO) significantly stimulated the proliferation and hematopoietic and/or endothelial differentiation of human bone marrow mononuclear cells and of purified CD34+, CD133+, kinase domain receptor-positive (KDR+), or CD34+/KDR+ cell populations. In the murine system, rhHAPO stimulated the proliferation of long-term culture-initiating cells (LTC-ICs) as well as CD34+ and stem cell antigen-1 (Sca-1+) cell subsets. In vivo, subcutaneous injection of rhHAPO into normal mice resulted in a significant increase in bone marrow hematopoietic cells. Furthermore, irradiated mice injected with rhHAPO had an enhanced survival rate and accelerated hematopoiesis. Our data suggest that HAPO is a novel growth factor acting on the primitive cells of both hematopoietic and endothelial cell lineages and that HAPO may have a clinical potential in the treatment of various cytopenias and radiation injury and in the expansion of hematopoietic and endothelial stem/progenitor cells.
The nature of early T lineage progenitors in the thymus or bone marrow remains controversial. Here we assess lineage capacity and proliferative potential among five distinct components of the earliest intrathymic stage (DN1, CD25(-)44(+)). All of these express one or more hemato-lymphoid lineage markers. All can produce T lineage cells, but only two of them display kinetics of differentiation, proliferative capacity, and other traits consistent with being canonical T progenitors. The latter also appeared limited to producing cells of the T or NK lineages, while B lineage potential derived mainly from the other, less typical T progenitors. In addition to precisely defining canonical early progenitors in the thymus, this work reconciles conflicting results from numerous groups by showing that multiple progenitors with a DN1 phenotype home to the thymus and make T cells, but possess different proliferative potentials and lineage capacities.
A detailed cell lineage of ascidian embryos has been available since the turn of the century. This cell lineage was deduced from the segregation of pigmented egg cytoplasmic regions into particular blastomeres during embryogenesis. The invariant nature of the cell lineage, the segregation of specific egg cytoplasmic regions into particular blastomeres, and the autonomous development of most embryonic cells suggests that cell fate is determined primarily by cytoplasmic determinants. Modern studies have provided strong evidence for the existence of cytoplasmic determinants, especially in the primary muscle cells, yet the molecular identity, localization, and mode of action of these factors are still a mystery. Recent revisions of the classic cell lineage and demonstrations of the lack of developmental autonomy in certain embryonic cells suggest that induction may also be an important mechanism for the determination of cell fate in ascidians. There is strong evidence for the induction of neural tissue and indirect evidence for inductive interactions in the development of the secondary muscle cells. In contrast to the long-accepted dogma, specification of cell fate in ascidians appears to be established by a combination of cytoplasmic determinants and inductive cell interactions.
This report continues our studies of the cell lineage relationships among the cells of the cerebellar Purkinje cell population. It examines the question of whether there are cell autonomous factors that regulate cell number during mammalian CNS development. Experimental aggregation chimeras were made by the joining of two embryos, one wild-type, one lurcher in genotype; both embryos were of C57BL/6 genetic background. Since all Purkinje cells of +/Lc genotype will degenerate, only wild-type Purkinje cells remain in the cerebellar cortex of the adult chimeras. The number of remaining cells does not vary uniformly from zero (the lurcher value) to wild-type (92,000 for C57BL/6). Rather the cells occur in numerical quanta that represent developmental clones of cells. In an earlier work, the Purkinje cell population of the C3H/HeJ inbred strain was shown to consist of eight such clones in each cerebellar half. Each C3H/HeJ clone contains 10,200 Purkinje cells. Evidence is presented in the present study that the Purkinje cells of the C57BL/6 strain, exist in 10 clones, of 9200 cells per half cerebellum. The findings suggest that a clonal organization exists in the Purkinje cell population of at least two inbred strains of mice, that differences in adult neuronal number can be due to either the number of clones present or the size of each individual clone (i.e., the number of cells per clone), and that the number of cells in a clone appears to be an autonomous property of the lineage itself and hence, presumably, of the progenitor cell that founded the clone.
Although CD45R/B220 is commonly used as a pan-B cell marker in the mouse, not all B220(+) cells belong to the B cell lineage. Here we report the characterization of a subpopulation of B220(+)CD19(-) cells in murine bone marrow, which failed to express markers that are present in early CD19(--) B cell precursors. Instead, these cells expressed low levels of MHC class II and CD11c, which are typically found on dendritic cells (DC). Moreover, these B220(+)CD19(-)CD11c(+) cells expressed Gr-1, indicating that they are related to the recently identified murine plasmacytoid DC or their progenitors. Therefore, we evaluated surface marker expression of the B220(+)CD19(-)CD11c(+) cells in lymphoid tissues of C57BL/6 mice, recombinase activating gene-1 deficient mice, lacking mature B and T lymphocytes, and mice with a targeted disruption of the Ig H chain mu membrane exon (mu MT), lacking mature B lymphocytes. When comparing bone marrow and spleen, we found that the surface profiles of B220(+)CD19(-)CD11c(+) cells were remarkably similar, indicating that they are in a comparable maturation or activation stage in the two lymphoid compartments. In addition, the almost complete absence of peripheral B220(+) B-lineage cells in mu MT mice allowed the anatomical localization of the B220(+)CD19(-)CD11c(+) cells to the red pulp and the T cell areas in the spleen. Taken together, our findings indicate that the mouse bone marrow contains a recirculating population of B220(+)CD19(-) CD11c(+) plasmacytoid DC, the development of which is largely independent of the presence of mature T and B cells.
Cell-transfer studies presented here distinguish three murine B cell lineages: conventional B cells, which develop late and are continually replenished from progenitors in adult bone marrow; Ly-1 B cells (B-1a), which develop early and maintain their numbers by self-replenishment; and Ly-1B "sister" (B-1b) cells, which share many of the properties of Ly-1 B cells, including self-replenishment and feedback regulation of development but can also readily develop from progenitors in adult bone marrow. The sequential emergence of these lineages, the time at which their progenitors function during ontogeny, and the distinctions among their repertoires and functions suggest that evolution has created a layered immune system in which the immune response potential of each successive lineage is adapted to its particular niche.
A key goal of biology is to understand the origin of the many cell types that can be observed during diverse processes such as development, regeneration, and disease. Single-cell RNA-sequencing (scRNA-seq) is commonly used to identify cell types in a tissue or organ. However, organizing the resulting taxonomy of cell types into lineage trees to understand the origins of cell states and relationships between cells remains challenging. Here we present LINNAEUS (Spanjaard et al, Nat Biotechnol 36:469-473. https://doi.org/10.1038/nbt.4124 , 2018; Hu et al, Nat Genet 54:1227-1237. https://doi.org/10.1038/s41588-022-01129-5 , 2022) (LINeage tracing by Nuclease-Activated Editing of Ubiquitous Sequences)-a strategy for simultaneous lineage tracing and transcriptome profiling in thousands of single cells. By combining scRNA-seq with computational analysis of lineage barcodes, generated by genome editing of transgenic reporter genes, LINNAEUS can be used to reconstruct organism-wide single-cell lineage trees. LINNAEUS provides a systematic approach for tracing the origin of novel cell types, or known cell types under different conditions.
Several cell types are present in the intestinal epithelium that likely arise from a common precursor, the stem cell, and each mature cell type expresses a unique set of genes that characterizes its functional phenotype. Although the process of differentiation is intimately linked to the cessation of proliferation, the mechanisms that dictate intestinal cell fate determination are not well characterized. To investigate the reprogramming of gene expression during the cell lineage allocation/differentiation process, we took advantage of a unique system of two clonal derivatives of HT29 cells, Cl16E and Cl19A cells, which spontaneously differentiate as mucus producing goblet and chloride-secreting cells, respectively, as a function of time. By profiling gene expression, we found that these two cell lines show remarkably similar kinetics of change in gene expression and common clusters of coordinately regulated genes. This demonstrates that lineage-specific differentiation of intestinal epithelial cells is characterized overall by the sequential recruitment of functionally similar gene sets independent of the final phenotype of the mature cells.
Embryonic stem cells can differentiate in vitro into hematopoietic cells through two intermediate stages; the first being FLK1(+) E-cadherin- proximal lateral mesoderm and the second being CD45(-) VE-cadherin+ endothelial cells. To further dissect the CD45(-) VE-cadherin+ cells, we have examined distribution of alpha4-integrin on this cell population, because alpha4-integrin is the molecule expressed on hematopoietic stem cells. During culture of FLK1(+) E-cadherin- cells, CD45(-) VE-cadherin+ alpha4-integrin- cells differentiate first, followed by alpha4-integrin+ cells appearing in both CD45(-) VE-cadherin+ and CD45(-) VE-cadherin- cell populations. In the CD45(-) VE-cadherin+ cell population, alpha4-integrin+ subset but not alpha4-integrin- subset had the potential to differentiate to hematopoietic lineage cells, whereas endothelial cell progenitors were present in both subsets. The CD45(-) VE-cadherin- alpha4-integrin+ cells also showed hematopoietic potential. Reverse transcription-polymerase chain reaction analyses showed that differential expression of the Gata2 and Myb genes correlated with the potential of the alpha4-integrin+ cells to give rise to hematopoietic cell differentiation. Hematopoietic CD45(-) VE-cadherin+ alpha4-integrin+ cells were also present in the yolk sac and embryonic body proper of 9.5 day postcoitum mouse embryos. Our results suggest that the expression of alpha4-integrin is a marker of the earliest precursor of hematopoietic cell lineage that was diverged from endothelial progenitors.
Steel factor (S1F), also known as stem cell factor, is a potent growth stimulator of hemopoietic progenitor cells. In the context of transplantation of hemopoietic cells to irradiated allogeneic hosts, natural killer (NK) cells exert restrictive control on hemopoietic cell proliferation, and are regularly found in elevated concentration in areas of intense hemopoiesis. The present study was designed to examine the effects with time of S1F in vivo on the numbers of NK cells, identified by the presence of the NK 1.1 surface molecule, in the spleen and bone marrow. Throughout the first 3 days of S1F exposure, NK cell numbers, in spite of rapid (1 day) and significant increases in the other hemopoietic cell lineages, did not change in either the spleen or the bone marrow. However, NK cells were increased 2-fold in both organs by 7 days of S1F exposure. At this time, immature granuloid and erythroid cells and the large lymphoid cells in the spleen had more than doubled their respective control numbers and in the bone marrow, immature granuloid cells increased by 47% of control levels. The presence of a late, but not early, influence of S1F on NK cells of the spleen and bone marrow suggests an indirect effect of S1F on this lineage, occurring only when S1F-stimulated hemopoiesis becomes sufficiently intense, providing, thus, an abundance of NK cell targets.
To investigate whether hemopoietic stem cells (HSCs) can differentiate into all lineage cells even in the thymus, we injected two types of HSCs (c-kit+ and c-kit < low cells) obtained from C57BL/6 Ly5.1 mice directly into the thymus of 7.5 Gy-irradiated C57BL/6 Ly5.2 mice. When c-kit < low cells (low density/lineage-/CD71-/major histocompatibility complex class I high/Sca-1+/Thy-1low/ c-kit < low) were injected, donor-derived (Ly5.1) cells were detected on day 8 after intrathymic (i.t.) injection, and the number reached a maximum on day 24 after injection. Granulocytes and macrophages were also detected on day 8 after injection. However, B220+ B cells were observed on day 13. Eighteen days after i.t. injection, the injected lobes showed red color due to the synchronous development of erythroid cells. Histological studies revealed the development not only of erythroid lineage cells but also of megakaryocytes in the thymus. In contrast, when c-kit+ cells were injected, a significant number of donor-derived cells were detected on day 5 after i.t. injection (three days earlier than in the case of c-kit < low cell injection). The differentiation into erythroid lineage cells was also observed six days earlier than when c-kit < low HSCs were injected. These findings suggest that c-kit < low HSCs are more primitive than c-kit+ HSCs, although both can differentiate into all lineage cells after i.t. injection.
Breast biology and pathology are currently shaped by the two-cell concept that recognizes only glandular and myoepithelial cells. In the present study, we have visualized a previously unidentified cell population within the epithelial compartment of the breast, which displays the phenotypic characteristics of a committed stem cell. Immunofluorescence double labeling with digital image processing and Western blotting were applied to normal breast tissue as well as to noninvasive and invasive breast cancers using antibodies to basal cytokeratin 5 (Ck5), glandular cytokeratins 8/18 (Ck8/18/19), and smooth muscle alpha-actin (SMA) as markers for myoepithelial cells (SMA). A distinct population of cells was identified that expressed Ck5 in the absence of Ck8/18/19 or SMA. These cells differentiate toward glandular epithelial or myoepithelial Ck5-negative end cells passing through either Ck5/Ck8/18/19 or Ck5/SMA-positive intermediates. Our experiments clearly demonstrate a precursor or committed stem cell function of the Ck5-positive cell that is responsible for regeneration of the human adult breast epithelium. However, the observation that the vast majority of breast cancers display the glandular epithelial immunophenotype strongly suggests that the neoplastic cells derive from a late stage of the glandular epithelial differentiation pathway. The significance of this new cell biological model is that it might serve as a tool to unravel the regulatory mechanisms that govern regeneration and abnormal proliferation of breast epithelium at the cellular level.
In this paper, we continue our examination of the role of cell lineage in the development of the cerebellar Purkinje cell population of the mouse. The analysis of Purkinje cell lineage is based on counts of the number of wild-type Purkinje cells in +/Lc<==>wild-type chimeras. +/Lc Purkinje cells undergo a cell autonomous degeneration early in postnatal development leaving variable numbers of wild-type Purkinje cells in chimeric animals. Using theoretical, statistical, and experimental approaches, we have tested various developmental models to account for the numerical development of Purkinje cell numbers in the +/Lc<==>wild-type chimeras. We have analyzed models based on the assumption that cell lineages are irrelevant to Purkinje cell development, as well as our own previous hypothesis that Purkinje cells descend from a small number of progenitor cells selected during the early stages of neurogenesis. The theoretical approach calculates the distributions of Purkinje cell numbers in hypothetical +/Lc<==>wild-type chimeras and inbred mice based on both clonal and nonclonal hypotheses of neuronal development. Variations of the model are compared with published cell counts from +/Lc<==>C3H/HeJ, +/Lc<==>C57BL/6J, +/Lc<==>AKR/J chimeras, and C3H/HeJ inbred mice. The statistical approach assesses the significance of the fits of the observed data with different variations of the model by Monte Carlo simulation techniques. The results of the comparison suggest that our observed data is more likely to be explained by a clonal model of development than by alternate models in which cell lineages play a minor role. Our experimental approach describes a new +/Lc<==>C3H/HeJ chimera in which all of the Purkinje cells (> 7900) are found on one side of the brain. We have analyzed this chimera with respect to clonal and nonclonal models of Purkinje cell development. The extreme asymmetric distribution of Purkinje cells provides added support to the hypothesis that there is a small number of progenitor cells that generate Purkinje cells. Our findings lead to the conclusion that while not all alternate models of mammalian CNS development can be completely excluded, the early progenitor hypothesis is the most probable model of Purkinje cell development.
The cellular response to periportal liver injury, induced by phenobarbital feeding and cocaine injection, is used to compare the restitutive proliferation of hepatocytes, cholangiocytes, and oval cells in the livers of normal control to those of interleukin-6 (IL-6) knockout mice. After this injury hepatocytes in noninjured middle and central zones start to proliferate first, followed by proliferation of cholangiocytes and intraportal oval cells. Proliferation of all cell types peaks at 2 days, but oval cells continue to proliferate and differentiate through days 4 and 6 as they reconstitute the necrotic zone. By day 10, the injured zone is completely repaired, and no dividing cells remain. During the first 3 to 4 days after injury, the number of proliferating hepatocytes, cholangiocytes, and sinusoidal cells is lower in IL-6 knockout mice than in normal mice, whereas the number of dividing oval cells is higher. However, overall repair of the injury is accomplished in the same time period in both groups. During repair of the periportal zone, oval cells acquire differentiation markers of hepatocytes as they cross the zone of injury. In conclusion, the phenobarbital/cocaine injury model is useful to study restitutive proliferation of mouse liver cell lineages. The proliferative response in IL-6 knockout mice shows that IL-6 is not required for proliferation of liver cells; timely repair of liver injury occurs in both normal and IL-6 knockout mice. Increased proliferation of oval cells in IL-6 knockout mice may compensate for the lower proliferation of other liver cell types.