Search results for "Cell Differentiation"
showing 10 items of 907 documents
Single cell cultures of Drosophila neuroectodermal and mesectodermal central nervous system progenitors reveal different degrees of developmental aut…
2009
Abstract Background The Drosophila embryonic central nervous system (CNS) develops from two sets of progenitor cells, neuroblasts and ventral midline progenitors, which behave differently in many respects. Neuroblasts derive from the neurogenic region of the ectoderm and form the lateral parts of the CNS. Ventral midline precursors are formed by two rows of mesectodermal cells and build the CNS midline. There is plenty of evidence that individual identities are conferred to precursor cells by positional information in the ectoderm. It is unclear, however, how far the precursors can maintain their identities and developmental properties in the absence of normal external signals. Results To s…
Stage-specific inductive signals in the Drosophila neuroectoderm control the temporal sequence of neuroblast specification.
2001
One of the initial steps of neurogenesis in the Drosophila embryo is the delamination of a stereotype set of neural progenitor cells (neuroblasts) from the neuroectoderm. The time window of neuroblast segregation has been divided into five successive waves (S1-S5) in which subsets of neuroblasts with specific identities are formed. To test when identity specification of the various neuroblasts takes place and whether extrinsic signals are involved, we have performed heterochronic transplantation experiments. Single neuroectodermal cells from stage 10 donor embryos (after S2) were transplanted into the neuroectoderm of host embryos at stage 7 (before S1) and vice versa. The fate of these cel…
Rat CNS cell culture. Enhancement of neuronal survival and delay of glial proliferation by serum from patients with multiple sclerosis. A morphologic…
1984
The addition of serum from multiple sclerosis (MS) patients to the culture medium of dissociated cells from cerebral hemispheres of rat embryos caused a delay in glial proliferation and an enhancement of neuronal survival. Sera from normal individuals and patients with other neurological diseases failed to show this effect. These morphological observations are interpreted as the outcome of inhibition of in vitro gliogenesis.
Binding of flunitrazepam to differentiating neurons cultured in a chemically defined, hormone-supplemented medium
1990
[3H]Flunitrazepam (FNZ) binding to cortical neurons from fetal rat brain was investigated in vitro. The use of a synthetic medium specific for neurons made it possible to plot a developmental curve of3H-FNZ binding in an almost pure neuronal culture. Detectable specific binding was present in vitro at time 0 (that is, the 16th gestational day). A progressive increase of binding, due to an increment in the number of recognition sites, was observed on the subsequent days. The affinity of the specific binding sites to3H-FNZ was enhanced by the addition of exogenous GABA, whereas the density was not affected. © 1990 Plenum Publishing Corporation.
Nanoscale Chemical Interaction Enhances the Physical Properties of Bioglass Composites
2013
Bioglasses are favorable biomaterials for bone tissue engineering; however, their applications are limited due to their brittleness. In addition, the early failure in the interface is a common problem of composites of bioglass and a polymer with high mechanical strength. This effect is due to the phase separation, nonhomogeneous mixture, nonuniform mechanical strength, and different degradation properties of two compounds. To address these issues, in this study a nanoscale interaction between poly(methyl methacrylate) (PMMA) and bioactive glass was formed via silane coupling agent (3-trimethoxysilyl)propyl methacrylate (MPMA). A monolith was produced at optimum composition from this hybrid …
Production of ceramides causes apoptosis during early neural differentiation in vitro.
2000
To investigate signal transduction pathways leading to apoptosis during the early phase of neurogenesis, we employed PCC7-Mz1 cells, which cease to proliferate and begin to differentiate into a stable pattern of neurons, astroglial cells, and fibroblasts upon incubation with retinoic acid (RA). As part of lineage determination, a sizable fraction of RA-treated cultures die by apoptosis. Applying natural long-chain C(16)-ceramides as well as membrane-permeable C(2)/C(6)-ceramide analogs caused apoptosis, whereas the biologically nonactive C(2)-dihydroceramide did not. Treating PCC7-Mz1 stem cells with a neutral sphingomyelinase or with the ceramidase inhibitor N-oleoylethanolamine elevated t…
Down-regulation of transcription factors AP-1, Sp-1, and NF-kappa B precedes myocyte differentiation.
1996
Terminal differentiation of myocytes involves withdrawal from the cell cycle, induction of myogenin expression, and finally formation of myotubes. To study the factors that regulate the initial phase of muscle differentiation, we analyzed the binding activities of transcription factors AP-1, Sp-1, and NF-kappa B in L6, C2C12, and rhabdomyosarcoma BA-Han-1C cells. Temporal changes in transcription factor binding activities were compared to the activation of myogenin promoter-driven CAT reporter gene and the expression level of myogenin, a master gene of myogenic differentiation. We observed a prominent decrease in the nuclear binding activities of AP-1, Sp-1, and NF-kappa B already 12 to 24 …
Chromatin remodelling factor Mll1 is essential for neurogenesis from postnatal neural stem cells
2009
Epigenetic mechanisms that maintain neurogenesis throughout adult life remain poorly understood(1). Trithorax group (trxG) and Polycomb group (PcG) gene products are part of an evolutionarily conserved chromatin remodelling system that activate or silence gene expression, respectively(2). Although PcG member Bmi1 has been shown to be required for postnatal neural stem cell self-renewal(3,4), the role of trxG genes remains unknown. Here we show that the trxG member Mll1 (mixed-lineage leukaemia 1) is required for neurogenesis in the mouse postnatal brain. Mll1-deficient subventricular zone neural stem cells survive, proliferate and efficiently differentiate into glial lineages; however, neur…
New emerging potentials for human Wharton's jelly mesenchymal stem cells: immunological features and hepatocyte-like differentiative capacity.
2010
In recent years, human mesenchymal stem cells (MSC) have been extensively studied. Their key characteristics of long-term self-renewal and a capacity to differentiate into diverse mature tissues favour their use in regenerative medicine applications. Stem cells can be found in embryonic and extra-embryonic tissues as well as in adult organs. Several reports indicate that cells of Wharton's jelly (WJ), the main component of umbilical cord extracellular matrix, are multipotent stem cells, expressing markers of bone marrow mesenchymal stem cells (BM-MSC), and giving rise to different cellular types of both connective and nervous tissues. Wharton's jelly mesenchymal stem cells (WJ-MSC) express …
A Mutually Stimulating Loop Involving Emx2 and Canonical Wnt Signalling Specifically Promotes Expansion of Occipital Cortex and Hippocampus
2005
The correct size of the different areas composing the mature cerebral cortex depends on the proper early allocation of cortical progenitors to their distinctive areal fates, as well as on appropriate subsequent tuning of their area-specific proliferation--differentiation profiles. Whereas much is known about the genetics of the former process, the molecular mechanisms regulating proliferation and differentiation rates within distinctive cortical proto-areas are still largely obscure. Here we show that a mutual stimulating loop, involving Emx2 and canonical Wnt signalling, specifically promotes expansion of the occipito-hippocampal anlage. Collapse of this loop occurring in Emx2 2/2 mutants …