bluuebunny/crossref_metadata_2025_split huggingface dataset:
Astrogliosis in culture: I. The model and the effect of antisense oligonucleotides on glial fibrillary acidic protein synthesis
Authors: Yu Albert C. H. , Lee Y. L. , Eng L. F. 
Published: January 2005

AbstractAstrogliosis is a predictable response of astrocytes to various types of injury caused by physical, chemical, and pathological trauma. It is characterized by hyperplasia, hypertrophy, and an increase in immunodetectable glial fibrillary acidic protein (GFAP). As GFAP accumulation is one of the prominent features of astrogliosis, inhibition or delay in GFAP synthesis in damaged and reactive astrocytes might affect astrogliosis and delay scar formation. The aim of this study is to investigate the possibility of utilizing antisense oligonucleotides in controlling the response of astrocytes after mechanically induced injury. We scratched primary astrocyte cultures prepared from newborn rat cerebral cortex with a plastic pipette tip as an injury model and studied the astrogliotic responses in culture. Injured astrocytes became hyperplastic, hypertrophic, and had an increased GFAP content. These observations demonstrate that injured astrocytes in culture are capable of becoming reactive and exhibit gliotic behaviors in culture without neurons. The increase in GFAP content in injured astrocytes could be inhibited by incubating the scratched culture with commerically available liposome complexed with 3′ or 5′ antisense oligonucleotides (20 nt) in the coding region of mouse GFAP. The scratch model provides a simple system to examine in more detail the mechanisms involved in triggering glial reactivity and many of the cellular dynamics associated with scar formation. Antisense oligonucleotide treatment could inhibit the GFAP synthesis in injured astrocytes, hence it may be applicable in modifying scar formation in CNS injury in vivo. © 1993 Wiley‐Liss, Inc.
Serotonin‐activated α2‐macroglobulin inhibits neurite outgrowth and survival of embryonic sensory and cerebral cortical neurons
Authors: Liebl D. J. , Koo P. H. 
Published: January 2005

AbstractMethylamine‐modified alpha‐2‐macroglobulin (MA‐α2M) has been recently shown to inhibit the biological activity of β‐nerve growth factor (NGF) in promoting neurite outgrowth by embryonic dorsal root ganglia in culture (Koo PH, Liebl DJ, J Neurosci Res 31:678–692, 1992). The objectives of this study are to determine whether α2M can also be modified by larger aromatic biogenic amines such as 5‐hydroxytryptamine (5HT; serotonin), the nature of interaction between NGF and 5HT‐modified alpha‐2‐M (5HT‐α2M), and the effect of 5HT‐α2M on the neurite extension and the growth of embryonic sensory and cholinergic neurons in 2 disparate animal species (chicken and rats). This study demonstrates that each mole of α2M can combine with 15.2 ± 1.8 moles of 5HT, in which up to 4.5 ± 0.4 moles may be covalently bonded. As determined by gel filtration and polyacrylamide gel electrophoresis studies, both 5HT‐α2M and normal α2M combine noncovalently with NGF, but 5HT‐α2M by comparison can combine with NGF somewhat more effectively. In contrast to normal α2M, 5HT‐α2M at concentrations greater than about 0.17 μM exerts a dose‐dependent inhibition on the NGF‐stimulated neurite outgrowth by embryonic dorsal root ganglia and dissociated cells in culture, and the inhibitory effect can be overcome by higher NGF concentrations. Both 5HT‐α2M and MA‐α2M at 1.0 μM inhibit neurite extension by embryonic rat cerebral cortical cells and seriously damage these cells in culture. Such neurite‐inhibitory activity, however, can only be partially blocked by extraneously added NGF alone. Normal α2M (at 1.0 μM) and 5HT (at 188 μM), on the other hand, under the identical conditions produce very little or no effect on the normal cellular and axonal growth of these cells. We conclude that α2M can potentially interact with nucleophilic monoamines, including neurotransmitters, to form inhibitory complexes which may inhibit/regulate NGF‐promoted neurite outgrowth and neuronal survival. In addition, higher concentrations of such complexes can seriously damage certain CNS neurons which do not depend solely on NGF for survival. © 1993 Wiley‐Liss, Inc.
Glial progenitor cells of the nerve fiber layer of the olfactory bulb: Effect of astrocyte growth media
Authors: Doucette R. 
Published: January 2005

AbstractThere are two morphologically distinct types of glial cells (i.e., ensheathing cells and astrocytes) in the nerve fiber layer (NFL) of the adult mammalian olfactory bulb. Ensheathing cells provide ensheathment for olfactory axons, whereas astrocytes occupy the interfascicular spaces of the olfactory NFL. During embryonic development, however, only one type of glial cell is found in this layer of the olfactory bulb, namely, the ensheathing cell. Even though ensheathing cells take up residence within the CNS, they are actually derived from the olfactory placode. Far less is known about the developmental origin of interfascicular astrocytes, which arise either from the glial progenitor cells that give rise to ensheathing cells or from astrocyte precursor cells that migrate into the NFL from deeper layers of the bulb primordium. In the present study, enriched populations of ensheathing cells were grown in vitro in media known to promote the growth and differentiation of astrocytes to determine whether ensheathing cell progenitors could differentiate into astrocytes. These media failed to induce the appearance of astrocytes in the ensheathing cell cultures. It was concluded that the astrocytes of the NFL most likely arise from progenitor cells that migrate into this layer from deeper parts of the developing bulb. © 1993 Wiley‐Liss, Inc.
Protease production by cultured microglia: Substrate gel analysis and immobilized matrix degradation
Authors: Colton C. A. , Keri J. E. , Chen W.‐T. , Monsky W. L. 
Published: January 2005

AbstractThe production of collagen‐degrading proteases by cultured neonatal rat microglia was examined using an immobilized fibronectin‐gelatin matrix coupled to a fluorescent marker and by substrate gel analysis. When microglia were plated onto the surface of the matrix and incubated under resting (nonstimulated) conditions, a small but visible amount of immobilized matrix was degraded. Treatment with lipopolysaccharide (LPS) or interleukin‐1 (IL‐1) significantly increased the number of microglia demonstrating substrate degradation. Substrate‐SDS polyacrylamide gel electrophoresis of samples of supernatants from untreated cultured microglia indicated the presence of a 72 and a 92 kD metalloproteinase with characteristics corresponding to collagenases. Supernatants from untreated astrocyte cultures were shown to have primarily a 72 kD metalloproteinase. Proteinase activity increased on stimulation of the microglia with LPS and IL‐1 in a dose‐dependent fashion. These results indicate that cultured microglia release active proteases capable of degrading the extracellular matrix in a localized region. The production of proteases by activated microglia may have important physiological and pathophysiological consequences within the restricted extracellular matrix of the CNS. © 1993 Wiley‐Liss, Inc.
Pathways of migration of transplanted Schwann cells in the demyelinated mouse spinal cord
Authors: Evercooren A. Baron‐van , Duhamel‐Clerin E. , Boutry J. M. , Hauw J. J. , Gumpel M. 
Published: January 2005

AbstractWe have studied the behavior of Schwann cells transplanted at a distance from an induced myelin lesion of the adult mouse spinal cord. These transplanted cells were mouse Schwann cells arising from an immortalized cell line (MSC80) which expresses several Schwann cell phenotypes including the ability to produce myelin. The behavior of MSC80 cells was compared to that of purified rat Schwann cells transplanted in the same conditions. Schwann cells were labeled in vitro with the nuclear fluorochrome Hoechst 33342 and were transplanted at distances of 2‐8 mm from a lysolecithin‐induced myelin lesion in the spinal cord of shiverer and normal mice. Our results show that transplanted MSC80 cells migrated toward the lesion, in both shiverer and normal mouse spinal cord, preferentially along the ependyma, meninges, and blood vessels. They also migrated along white matter tracts but traveled a longer distance in shiverer (8 mm) than in normal (2‐3 mm) white matter. Using these different pathways, MSC80 cells arrived within the lesion of shiverer and normal mouse spinal cord at the average speed of 166 p, m/hr (8 mm/48 hr). Migration was most efficient along the ependyma and the meninges where it attained up to 250 μm/hr. Migration was much slower in white matter tracts (95 μm/hr ± 54 in the shiverer and only 38 pm/hr ± 3 in the normal mouse). We also provide evidence for the specific attraction of MSC80 cells by the lysolecithin‐induced lesion since (1) their number increased progressively with time in the lesion, and (2) MSC80 cells left their preferential pathways of migration specifically at the level of the lesion. Finally, combining the Hoechst Schwann cell labeling method with the immunohistochemical detection of the peripheral myelin protein, PO, we show that some of the MSC80 cells which have reached the lesion participate in myelin repair in both shiverer and normal lesioned mouse spinal cord. A series of control experiments performed with rat Schwann cells indicate that the migrating behavior of transplanted MSC80 cells was identical to that of purified but non‐immortalized rat Schwann cells. © 1993 Wiley‐Liss, Inc.
Uptake, release and metabolism of alaume in neurons and astrocytes in primary cultures
Authors: Westergaard N. , Varming T. , Peng L. , Sonnewald U. , Hertz L. , Schousboe A. 
Published: January 2005

AbstractThe uptake, release, and metabolism of alanine were studied in primary cultures of cerebral cortical neurons or astrocytes and cerebellar granule neurons. All three cell types exhibited a saturable, sodiumdependent uptake of alanine with KM values (ULM) of 256 ± 30, 463 ± 39, and 292 ± 39, respectively, and V values (nmol/min/mg) of 15.9 ± 0.7,7.9 ± 0.01, and 17.4 ± 0.8, respectively. The corresponding val' ues < nmol/min/mg for the specific activity of alanine aminotransferase were 4.7 ± 0.4, 17.1 ± 2.5, and 4.5 ± 0.9 (all values represent the mean ± SEM). Release of alanine from the cells was rectilinear with time over a 10 hr period in case of astrocytes (40 nmol/hr/ mg) and cerebellar granule neurons (21 nmol/hr/mg). In cortical neurons the release rate declined from an initial value of 19 nmol/hr/mg during the first 3 hr to a value of less than 3 nmol/hr/mg during the subsequent 7 hr of incubation. Metabolism of [14C]alanine to 14CO2 was found to have a lag period of 15 min and subsequently the rate of CO2 production was constant over a 45 min period with a value of 0.5 nmol/min/mg in granule neurons and about 0.3 nmol/ min/mg in the other two cell types. Altogether the results show that alanine is preferentially produced in and released from astrocytes and accumulated into both GABAergic cortical neurons and gintamatergic cerebellar granule neurons. © 1993 Wiley‐Liss, Inc.
Localization of basic proteins in human myelin
Authors: McLaurin J. , Ackerley C. A. , Moscarello M. A. 
Published: January 2005

AbstractThe myelin basic protein (MBPs) represent a family of proteins (charge isomers) which account for 35% of the total myelin protein. Localization studies have been inconclusive because MBP is not a single protein. Antibodies obtained by injection of MBP into animals recognized all members of the MBP family. In the studies reported here, we have fractionated the MBPs into specific components or charge isomers. One of these which contains citrulline accounts for about 20% of the total MBP. We report the localization of this single MBP to the intraperiod line of myelin by immunoelectron microscopy. For these studies several specific antibodies were used including antibodies raised against total MBP, specific MBP peptides, and against a tetracitrulline peptide. This latter antibody was specific for component 8 (C‐8) of MBP. Since C‐8 is the only MBP which contains citrulline it was used to localize this particular form of MBP principally to the intraperiod line by immunogold electron microscopy, while antibody against total MBP (consisting of all charge isomers C‐1→C‐8) labelled both the major dense line and the intraperiod line. When the anti‐citrulline antibody was used with a 3 nm gold conjugated Fab fragments prepared from the secondary antibody, 66.5% of the gold particles were localized to the intraperiod line, while 11.2% of gold particles were localized to the major dense line. On the other hand, with the monoclonal anti‐MBP antibodies reactive with residues 69–74, 59.4% of the gold particles were localized to the major dense line and 23.6% of gold particles at the intraperiod line. Other supporting evidence includes increased labelling of myelin by 125I labelled anti‐citrulline IgG when isolated myelin was swollen, a process known to take place at the intraperiod line. Gold particles were demonstrated at the intraperiod line in swollen and recompacted myelin. C‐8 was shown to associate preferentially with lipids asymmetrically localized to the intraperiod line. © 1993 Wiley‐Liss, Inc.
Reverse transcription and polymerase chain reaction technique for quantification of mRNA in Primary astrocyte cultures
Authors: Murphy G. M. , Jia X. ‐C. , Yu A. C. H. , Lee Y. L. , Tinklenberg J. R. , Eng L. F. 
Published: January 2005

AbstractThe reverse transcription and polymerase chain reaction technique (RT‐PCR) was assessed for the quantification of changes in mRNA levels from primary astrocyte cultures. The effects of dibutyryl cyclic AMP (dBcAMP) on glial fibrillary acidic protein (GFAP) mRNA and the effects of tumor necrosis factor‐alpha (TNF‐α), interlekin‐1 beta (IL‐1β), and lipopolysaccharide (LPS) on interleukin‐6 (IL‐6) mRNA were examined. Two quantitative PCR methods were used: one involved carrying out the reaction in the exponential phase and the other involved the coamplification of a competitive target sequence. Increased GFAP mRNA in response to chronic dBcAMP treatment and increased IL‐6 mRNA in response to TNF‐α/IL‐1β were readily detected. Both RT‐PCR techniques were found to be suitable for the detection of large as well as smaller (twofold) changes in mRNA levels. The advantages and limitations of RT‐PCR for mRNA quantification are discussed. © 1993 Wiley‐Liss, Inc.
Cell biology of neuronal endocytosis
Authors: Parton R. G. , Dotti C. G. 
Published: January 2005

AbstractEndocytosis is the process by which cells take in fluid and components of the plasma membrane. In this way cells obtain nutrients and trophic factors, retrieve membrane proteins for degradation, and sample their environment. In neuronal cells endocytosis is essential for the recycling of membrane after neurotransmitter release and plays a critical role during early developmental stages. Moreover, alterations of the endocytic pathway have been attributed a crucial role in the pathophysiology of certain neurological diseases. Although well characterized at the ultrastructural level, little is known of the dynamics and molecular organization of the neuronal endocytic pathways. In this respect most of our knowledge comes from studies of non‐neuronal cells. In this review we will examine the endocytic pathways in neurons from a cell biological viewpoint by making comparisons with non‐neuronal cells and in particular with another polarized cell, the epithelial cell. © 1993 Wiley‐Liss, Inc.
Protein growth factor requirements of rat neural crest cells
Authors: Bannerman P. G. , Pleasure D. 
Published: January 2005

AbstractNascent neural crest cells derived from explanted E12 embryonic rat caudal neural tubes were used as an assay system to investigate the effects of fibroblast growth factors on neural crest cell (NCC) survival, proliferation, migration, and differentiation. In vitro and in vivo all NCC express low affinity nerve growth factor receptors (p75‐LNGFR), whereas a subpopulation of NCC expresses the carbohydrate epitope recognized by the monoclonal antibody HNK‐1 (Bannerman and Pleasure, manuscript in preparation). Both acidic and basic fibroblast growth factor (FGF) promoted the survival of proportionally greater numbers of p75‐LNGF+/HNK‐1− than P75‐LNGFR+/HNK‐1+ NCC. An as yet uncharacterized factor present in neural tube‐conditioned medium was also required for NCC survival. Mitosis was frequent in those NCC closest to the neural tube, less so as the cells migrated away. Neither basic nor acidic fibroblast growth factor (FGF) influenced rates of NCC mitosis in either of these locations, nor did these FGFs alter the rate at which nascent NCC migrated away from the neural tube. However, acidic and basic FGFs did delay the differentiation of neural crest derived neurons in the cultures. FGF is abundant in the embryonic rat neural crest outgrowth zone, and the present study strongley supports an essential role for fgf in early development of the mammalian neural crest. © 1993 Wiley‐Liss, Inc.
Demyelination in a transgenic mouse: A model for multiple sclerosis
Authors: Mastronardi F. G. , Ackerley C. A. , Arsenault L. , Roots B. I. , Moscarello M. A. 
Published: January 2005

AbstractA transgenic mouse containing 70 copies (ND4) of the transgene encoding DM20, a myelin proteolipid protein, appeared clinically normal up to 3 months of age. By 8–10 months, it showed tremors, unsteady gait, and dies shortly thereafter. We concluded that the clinical symptoms correlated with demyelination based on the following criteria: (1) at 10 months of age only 17% of the amount of myelin obtained from normal mice was isolated from the ND4 mice; (2) astrogliosis, a prominent feature of demyelinating disease was minimal at 3 months of age but prominent by 10 months; (3) at the electron microscopic level disrupted myelin was seen at 8 months of age in the ND4 mice and ingested myelin debris was found in astrocytes; (4) lymphocytic infiltration in association with endothelial cells was observed routinely in the ND4 mice; (5) sections through optic nerves showed denuded and thinly myelinated axons in the 8 month old ND4 mice.Although the mechanism by which demyelination takes place is not fully understood, measurements of the amounts of PLP suggest it is down‐regulated by the large amount of DM20. Since DM20 is a major proteolipid in the young but a minor one in the adult, the persistence of high levels in the adult results in improperly assembled myelin which is prone to disruption. Therefore demyelination in the ND4 mouse appears to result from the persistence of immature myelin into the adult. © 1993 Wiley‐Liss, Inc.
Synaptic and photoreceptor components in retinal pigment epithelial cell transplanted retinas of Royal College of Surgeons dystrophic rats
Authors: Sheedlo H. J. , Li L. , Barnstable C. J. , Turner J. E. 
Published: January 2005

AbstractPlexiform layer synaptic and photoreceptor cell components were investigated in retinas of Royal College of Surgeons (RCS) dystrophic rats transplanted with normal retinal pigment epithelial (RPE) cells by immunocytochemistry using previously characterized monoclonal antibodies. In retinas of normal adult rats and RPE‐cell transplanted retinas of 4 month‐old RCS rats, HNK‐1, a marker for a carbohydrate of the neural cell adhesion molecule (N‐CAM), was detected immunocytochemically in the inner and outer plexiform layers and ganglion cell bodies and their axons. HNK‐1 was also detected in the inner plexiform layer of nontreated retinas of 4 month‐old RCS rats, but was reduced to scattered patches in the outer plexiform layer. In addition, immunoreactivity for the SVP‐38 antibody recognizing synaptophysin was found in both plexiform layers of normal adult rat retinas and RPE‐transplanted retinas of 4 month‐old RCS rats. Furthermore, photoreceptor cell bodies and their inner and outer segments were immunostained for the opsin monoclonal antibody RET‐P1 in retinas of normal adult rats and RPE‐cell transplanted retinas of 4 month‐old RCS rats. However, in nontreated retinas of 4 month‐old RCS rats, only immunostained debris material was detected. These results strongly suggest that normal RPE transplants not only rescue photoreceptor cells in RCS rats, but also maintain an essential functional capacity, in this case, synaptic components in the plexiform layers. © 1993 Wiley‐Liss, Inc.
Characterization of the cis‐acting elements of the mouse myelin P2 promoter
Authors: Bharucha V. A. , Peden K. W. C. , Subach B. R. , Narayanan V. , Tennekoon G. I. 
Published: January 2005

AbstractMyelin P2 is a basic protein of an apparent molecular weight of 14,800. Expression of P2 has been found largely in the cytosol of Schwann cells in the peripheral nervous system. Although the function of P2 is unknown, its striking homology to a family of fatty acid binding proteins has led to the idea that P2 may function as a fatty acid transport molecule. To investigate the DNA elements that control the expression of P2, sequences 5′ to the coding region were cloned upstream of the cat reporter gene. A series of 3′ and 5′ promoter mutants was constructed and their activity determined following transfection into secondary Schwann cells and the MT4H1 Schwann cell line. Using this strategy, we have identified a 217 bp silencer region and a 142 bp positive regulatory region. In addition, we have localized the 5′ flanking sequences in the promoter that are responsive to cAMP induction and to the transcription factor CCAAT/enhancer binding protein (C/EBP). © 1993 Wiley‐Liss, Inc.
Expression of the receptor tyrosine kinase c‐kit in oligodendrocyte progenitor cells
Authors: Ida J. A. , Dubois‐Dalcq M. , McKinnon R. D. 
Published: January 2005

AbstractThe growth and differentiation of neural precursor cells in the central nervous system (CNS) are regulated by their response to polypeptide growth factors which interact with specific transmembrane receptor tyrosine kinases (RTKs). We demonstrate that rat oligodendrocyte‐type 2 astrocyte (O‐2A) glial progenitor cells, precursors of the myelin‐forming cells in the CNS, express the transmembrane RTK c‐kit, the gene product of the murine dominant white spotting (W) locus and receptor for stem cell factor. Expression of c‐kit transcripts and immunoreactive protein is lost when O‐2A progenitors differentiate into postmitotic oligodendrocytes. Analysis of developing rat brain revealed an increase in the expression of c‐kit transcripts between postnatal days 10 and 12, a window of time preceding the emergence of oligodendrocytes and the onset of myelination in vivo. Expression of c‐kit in vitro and in vivo suggests a role for this receptor and its ligand during oligodendrocyte development. © 1993 Wiley‐Liss, Inc.
Bactenecin, a leukocytic antimicrobial peptide, is cytotoxic to neuronal and glial cells
Authors: Radermacher S. W. , Schoop V. M. , Schluesener H. J. 
Published: January 2005

AbstractSmall antimicrobial peptides are abundantly produced by leukocytes. These peptides are active against a broad range of pathogens, notably bacteria, fungi, and enveloped viruses, but hardly anything is known about their physiological and pathophysiological relevance.We observed that bactenecin, a dodecapeptide, is strongly cytotoxic ro rat embryonic neurons, fetal rat astrocytes and human gliblastoma cells. This neurotoxicity is unique to bactenecin, as a panel of antibacterial peptides from vertebrates and invertebrates, like defensins, corticostatin, indolicidin, ceropin P1, tachyplesin I, the magainings, or apidaecins did not impair neuronal viability. © 1993 Wiley‐Liss, Inc.