bluuebunny/crossref_metadata_2025_split huggingface dataset:
HSP72 induction by heat stress is not universal in mammalian neural cell lines
Authors: Satoh J. , Tabira T. , Yamamura T. , Kim S. U. 
Published: January 2005

AbstractHeat‐induced expression of 72‐kDa heat shock protein (HSP72) was investigated in a panel of neuronal and non‐neuronal cell lines by immunoblotting and immunocytochemistry using monoclonal antibodies directed to HSP72. By immunoblotting, HSP72 expression was observed in most cell lines of mouse (SN6.1b, CL8c4.7, NSC34.6, B2A, C2C12), RAT (PC12, C‐6, L3), and human (NB‐1, GOTO, IMR‐32, Hela) origin under the heat‐stressed condition. The mouse neuroblastoma cell line N18TG2, however, did not express HSP72 under the heat‐stressed condition. By immunocytochemistry, HSP72 was undetectable in the heat‐stressed N18TG2 cells, while it was identified in the heat‐stressed SN6.1b cells, a clonal hybrid neuron between N18TG2 and mouse septal cholinergic neuron. By exposure to a priming sublethal heat shock, SN6.1b cells but not N18TG2 cells acquired a significant level of tolerance to a subsequent lethal heat shock. These results suggest that heat‐induced expression of HSP72 may contribute to acquisition of the thermotolerant state in SN6.1b cells. © 1994 Wiley‐Liss, Inc.
Neuroprotective activity of acetyl‐L‐carnitine: Studies in vitro
Authors: Forloni G. , Angeretti N. , Smiroldo S. 
Published: January 2005

AbstractThe neuroprotective properties of acetyl‐L‐carnitine (ALCAR) were investigated in primary cell cultures from rat hippocampal formation and cerebral cortex of 17‐day‐old rat embryos. Chronic exposure to ALCAR (10–50 μM), reduced the cell mortality induced by 24 hr fetal calf serum deprivation. Protection was partial when the neuronal cells, chronically treated with ALCAR (50 μM,) were exposed to glutamate (0.25‐1 mM)and kainic acid (250–500 μM) for 24 hr. The neurotoxity induced by N‐methyl‐D‐aspartate (NMDA, 250 μm) was attenuated by the acute co‐exposure with ALCAR (1mM), the chronic treatment with ALCAR (50 μM)significantly reduced the neuronal death induced by NMDA (0.25–1mM) Cell mortality was also investigated in ALCAR‐treated hippocampal cultures chronically treated with β‐amyloid fragment 25–35. ALCAR appeared to have neuroprotective activity. This suggests an explanation of the positive results obtained with ALCAR in the treatment of alzheimer's disease. © 1994 Wiley‐Liss, Inc.
Thrombin receptor peptides induce shape change in neonatal murine astrocytes in culture
Authors: Beecher K. L. , Andersen T. T. , Fenton J. W. , Festoff B. W. 
Published: January 2005

AbstractAstrocytes appear star‐shaped in the brain, increasingly so after injury. When astroglia are cultures in serum‐containing medium, they exhibit a flat, fibroblast‐like morphology. In serum‐free medium, astrocytes become stellate, with many long processes. The serine protease α‐thrombin mimics the effects of serum at subnanomolar concentractions, whereas the thrombin‐inhibiting serpin, protease nexin I (PNI), reverses the thrombin effect. In our current experiements, murine neonatal spinal cord astrocytes became stellate after 4 hr in serum‐free medium, while cortical astrocytes requires 12 hr in serum‐free medium for stellation. Astrocytes from either region flattened after 60 min in medium containing 3.0 to 300 pM proteoloytically active human α‐thrombin. After 12 hr in thrombin‐containing medium, 98% of the astrocytes had a flattened morphology. No flattening occured if α‐thrombin was replaced by γ‐thrombin, which has its fibrinogen‐recognition exosite disrupted. PNI added at 1 nM to serum‐containing medium caused stellation after 3 hr, and astroglia were 50% stellate by 12 hr. The effect of thrombin was mimicked by a 7‐amino acid peptide (TRP‐7) action on astrocytes. These results indicate that astrocytes possess a cell surface receptor for thrombin, similar to that described for platelets, endothelial cells, and neurons. © 1994 Wiley‐Liss, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.
Neurotrophic‐4/5 is a survival factor for embryonic midbrain dopaminergic neurons in enriched cultures
Authors: Hynes M. A. , Poulsen K. , Armanini M. , Berkemeier L. , Phillips H. , Rosenthal A. 
Published: January 2005

AbstractParkinson's disease is a prevalent neurological disease characterized by profound and incapacitating movement disorders. A common pathology in Parkinson's patients is degeneration of substantia nigra dopaminergic neurons that innervate the striatum and a corresponding decrease in striatal dopamine content. We now report that NT‐4/5 can prevent the death of rat embryonic substantia nigra dopaminergic neurons in low density, enriched, primary cultures. Furthermore, these neurons express messenger RNA encoding the trkB receptor for NT‐4/5 and transcripts for NT‐4/5 are present in their environment. In addition, we demonstrate that NT‐4/5 protects embryonic dopaminergic neurons from the toxic effects of the neurotoxin MPP+ THUAS, nt‐4/5 could be a physiological survival factor for midbrain dopaminergic neurons and may be useful as a therapeutic agent for parkinson's disease. © 1994 Wiley‐Liss, Inc.
Re‐expression of glia‐derived nexin/protease nexin 1 depends on mode of lesion‐induction or terminal degeneration: Observations after excitotoxin or 6‐hydroxydopamine lesions of rat substantia nigra
Authors: Scotti A. L. , Monard D. , Nitsch C. 
Published: January 2005

AbstractThe serine protease inhibitor and neurite outgrowth promoter glia derived nexin (GDN) is expressed in the rat CNS during embryogenesis and persists in the olfactory system of the adult where receptor neurons are replaced throughout life. We investigated whether GDN‐immunoreactivity also appears in the adult at sites of synaptic rearrangement following nerve cell death and anterograde terminal degeneration in experimental models for Parkinson's disease. Rat substantia nigra was unilaterally lesioned by stereotaxic application of different toxins: 6‐hydroxydopamine, which selectively destroys dopaminergic neurons, the excitotoxic glutamate analog ibotenic acid, or the glutamate receptor agonists N‐methyl‐D‐aspartate and quisqualate, which cause circumscript lesions of the whole substantia nigra. Nerve cell death and astroglial reactivity were monitored by parallel cresyl staining and immunocytochemistry for glial fibrillary acidic protein, at survival times ranging from 2 to 100 days.Sustained de novo synthesis of GDN occurred in the dopamine depleted caudate putamen following excitotoxin or 6‐hydroxydopamine induced degeneration of the substantia nigra and of the nigrostriatal pathway provided that the lesions were nearly complete. This is consistent with compensatory changes occurring in deafferented caudate putamen and suggests a permissive role of GDN in neuronal plasticity.In the substantia nigra astroglia exhibited GDN‐immunoreactivity following excitotoxin injection but not after application of 6‐hydroxydopamine. Thus differences in action mechanisms of neurotoxins may have distinct consequences on the astrocyte mediated response of the same affected brain region. © 1994 Wiley‐Liss, Inc.
Distribution and differentiation of A2B5+ glial precursors in the developing rat spinal cord
Authors: Fok‐Seang J. , Miller R. H. 
Published: January 2005

AbstractIn many regions of the rat central nervous system, oligodendrocytes develop from migratory A2B5+ precursor cells. In the rat spinal cord, during early embryonic development the capacity for oligodendrogenesis appears to be restricted to ventral regions of the spinal cord, while cultures of postnatal rat spinal cord contain a distinct population of A2B5+ astrocyte precursors. To determine if, as in other regions of the CNS, spinal cord A2B5+ cells give rise directly to oligodendrocytes and astrocytes, the initial distribution, and subsequent dispersion, proliferation, and differentiation of spinal cord A2B5+ cells have been examined in both explant and dissociated cell cultures. Spinal cord oligodendrocytes develop from A2B5+ cells. At E14, A2B5+ cells are restricted to ventral regions of the spinal cord and as development proceeds they become more uniformly distributed throughout the spinal cord. In explant cultures, greater than 95% of the explants that contain oligodendrocytes also contain A2B5+ cells and a proportion of mature oligodendrocytes retain detectable A2B5 immunoreactivity briefly on their surface. The maturation of spinal cord oligodendrocyte precursors occurs in a number of distinct stages characterized by the expression of O4 immunoreactivity, which first appears at E16, and GC immunoreactivity, which first appears at E18. As spinal cord oligodendrocyte precursors acquire O4 immunoreactivity they appear to lose the ability to proliferate in response to PDGF but retain the ability to proliferate in response to bFGF, suggesting that the control of proliferation of oligodendrocyte precursors is, in part, dependent on their maturational state. In the presence of high serum, spinal cord A2B5+ cells fail to develop in isolated E14 dorsal spinal cord cultures, while in ventral cultures they subsequently differentiate into A2B5+ astrocytes suggesting that A2B5+ astrocyte precursors are also initially ventrally located. Unlike oligodendrocyte differentiation, however, the differentiation of spinal cord A2B5+ cells into astrocytes is delayed in early embryonic‐derived cultures compared to those from older animals. These observations suggest that local influences may regulate the timing of spinal cord A2B5+ astrocyte development, but not spinal cord oligodendrocyte development. © 1994 Wiley‐Liss, Inc.
Transient expression of 3,5,3′‐triiodothyronine nuclear receptors in rat oligodendrocytes: In vivo and in vitro immunocytochemical studies
Authors: Besnard F. , Luo M. , Miehe M. , Dusssault J. H. , Puymirat J. , Sarliève L. L. 
Published: January 2005

AbstractIt is generally accepted that the action of thyroid hormones is mediated through specific nuclear receptors. Recent studies have demonstrated the homology of the thyroid receptor with the cellular product of the oncogen v‐erbA. So far, two genes have been identified and classified as α and β subtypes. In this study, the expression of nuclear triiodothyronine (T3) receptors (NT3RS) was examined in secondary cultures containing 85–90% oligodendrocytes (OL) prepared from newborn rat brain primary cultures enriched in OL. These cultures, which are able to produce myelin membranes, were examined by double immunolabelling with a monoclonal antibody (2B3) raised against purified rat liver NT3Rs and with antibodies against two maturation markers of OL: an early marker, galactocerebroside (GC), and myelin basic protein (MBP), which is expressed later than GC. 2B3 recognized three nuclear proteins with the same molecular weights as β, α1, and α2 sybtypes with different capacities for binding T3. In 5‐day ‐old OL secondary cultures (25 days, total time in culture), 2B3‐NT3R immunoreactivity was located in 77% of morphologically immature OL (GC)+ cells, whereas only 44% of morphologically mature OL were immunoreactive. Only 35% of the MBP+ cells co‐expressed NT3Rs. In the corpus callosum of devloping rat brain, at all ages studied from 7–60 days postnatal, the total absence of NT3Rs in dark OL (morphologically mature), confirmed by ultrastructural immunocytochemistry, indicates an even more dramatic decrease during maturation. Furthermore, the percentage of medium OL (less mature) stained by 2B3 is reduced by approximately half in 60‐ compared to 20‐day‐old rat brain. It is of interest to note that the in vitro observation with maturation markers mirrors the in vivo decrease of NT3R expression during development. It is intersting that NT3Rs are absent in vivo before the critical period of active myelination. These data indicate the presence of a nuclear T3 binding protein in the nuclei of OL at the time of myelination both in vitro and in vivo. The transient expression of these NT3Rs during active myelination argues in favour of a direct effect of thyroid hormones on OL. © 1994 Wiley‐Liss, Inc.
Amyloid precursor protein is enriched in axolemma and periaxolemmal‐myelin and associated clathrin‐coated vesicles
Authors: Sapirstein V. S. , Durrie R. , Berg M. J. , Marks N. 
Published: January 2005

AbstractThe amyloid precursor protein (APP) is widely distributed within the CNS, where it is expressed in both neurons and glia. We have isolated axolemma and periaxolemmal‐myelin from rat brain and have determined by Western blot that APPs, Mr 100–110 kDa, are major constituents of these membrane. Isolation of axolemma, periaxolemmal‐myelin, and compact myelin show that while APP represents 1 and 0.6% of the proteins of these respective membranes, it is absent from compact myelin. These results indicate that APP transported down the axon is deposited at sites in the axolemma as well as the synapse, and that within the myelin complex, APP is targeted to the periaxolemmal domain. Both axolemma and periaxolemmal‐myelin contained a 10.5 kDa APP peptide which, based on reactivity with anti‐C‐terminal APP antibodies but not with anti‐N‐terminal antibody, appears to be a membrane‐associated C‐terminal fragment. Western blots with antibodies to Alzheimer precursor‐like proteins (APLP) indicate that APP immune reactivity is not a result of cross reactivity with APLPs. Isolation of axolemma from human autopsy material showed nearly identical results with a clear enrichment, relative to homogenate, of APP Mr 100–100 and the 10.5 kDa C‐terminal peptide. The demonstration of APP in axolemma and periaxolemmal‐myelin was replicated in membrane isolated from bovine brain. Bovine studies were extended to analysis of white matter clathrin‐coated vesicles; these data show that coated vesicles isolated from white matter, under conditions that previous studies indicate are largely endocytic vesicles, contain levels of APP comparable to that found in axolemma and periaxolemmal‐myelin. In addition, these vesicles contain cysteinly and aspartyl proteases. Incubation of axolemma with cathepsin B at pH 6.0 caused a rapid loss in the immune reactivity of APP Mr 100–110 and Mr 10.5 when analyzed with antibodies to APP672–695. This appears to be the result of hydrolysis within the epitope and not proteolysis of APP or the C‐terminal peptide, since no loss of reactivity was observed when analyzed with antibodies to sites more distal to the C‐terminus. Thus, cathepsin B hydrolyses membrane bound APP close to the C‐terminus and may be a useful tool for altering C‐terminal APP function. © 1994 Wiley‐Liss, Inc.
Differential accumulation of gangliosides by the brains of MPTP‐lesioned mice
Authors: Saulino M. F. , Schengrund C.‐L. 
Published: January 2005

AbstractAlthough gangliosides have been reported to enhance recovery from 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐induced lesions of the substantia nigra, evidence as to whether the administered gangliosides actually reach this or any other site of lesion in the central nervous system (CNS) at which they putatively enhance recovery is lacking. Therefore, studies were carried out to determine the amount of 3H‐labeled ganglioside that was accumulated by the brains of MPTP‐treated mice as well as by brains of control mice. No significant difference in the accumulation of 3/‐bovine brain gangliosides or 3H‐GD1a was seen between lesioned and control brains up to 240 min after injection of the labeled lipids. However, significantly more label was associated with the brains of MPTP‐treated mice compared to controls 120 and 240 min after the injection of 3H‐GM1. Analysis of the lipids extracted from the brain of a 3H‐GM1‐treated mouse revealed that the majority of label was still associated with 3‐GM1, 240 min after its administration. Autoradiography of tissue sections from the brains of MPTP‐treated mice injected with 3H‐GM1 showed that label was present in the ventricular spaces of the brain. This observation suggests that the administered gangliosides are present in the cerebrospinal fluid, which indicates that they have the potential to reach the lesioned CNS site at which they putatively enhance recovery. © 1994 Wiley‐Liss, Inc.
Modulation of neurofibromatosis type 1 gene expression during in vitro myoblast differentiation
Authors: Gutman D. H. , Cole J. L. , Collins F. S. 
Published: January 2005

AbstractNeurofibromin, the protein product of the neurofibromatiosis type 1 (NF1) gene, has two alternate isoforms which are generated by alternative splicing of two exons. One of these isoforms containing exon 48a is expressed at highest levels in muscle. Since neurofibromin is a p21‐ras regulator and has been recently shown to be modulated during Schwann cell differentiation, we examined the expression of the NF1 gene product during in vitro muscle differentiation. Previous work demonstrated that C2 © 1994 Wiley‐Liss, Inc. C12murine myoblast cell differentiation could be blocked by the introduction of an activated p21‐ras protein. Using this model system, we demonstrate that differentiationg C2C12 cells upregulate the expression ofNF1 mRNA by 2 days of serum starvation concomitant with increased expression of nicotinic acetylcholine receptor mRNA. This upregulation of mRNA expression paralleled an increase in neurofibromin and N‐ras levels, but no change in the relative abundance of the isoforms containing exon 23a or exon 48a was observed during in vitro myoblast differentiation. The increase in neurofibromin levels paralleled a decrease in the levels of activated p21‐ras as assayed by in vivo 32Porthophosphate incorporation into p21‐ras. These results suggest that in vitro C2C12 cell differentiation is associated with a concomitant increase in NF1 gene expression and decrease in the proportion of activated p21‐ras. © 1994 Wiley‐Liss, Inc.
Cloning and expression of inducible nitric oxide synthase from rat astrocytes
Authors: Galea E. , Reis D. J. , Feinstein D. L. 
Published: January 2005

AbstractIn primary cultures of rat astroglial cells exposure to bacterial endotoxin lipopolysaccharide (LPS) causes induction of a Ca2+‐independent form of the nitric oxide synthase (iNOS) enzyme. We have now cloned the mRNA encoding astroglial iNOS using a combination of cDNA library screening and polymerase chain reaction (PCR) amplification with degenerate oligonucleotides directed against conserved regions of all NOS enzymes. The sequence of astroglial iNOS cDNA is highly similar to the mouse macrophage sequence, having an overall homology of 92% at the DNA level and 93% at the protein level. As in other NOSs, canonical binding sites for redox cofactors are present. The 3′‐untranslated region displays 4 consensus AU‐pentamers, 2 polyadenylation sites, and terminates in a stretch of 17 adenosine residues. In situ hybridization studies with LPS‐treated astrocyte cultures demonstrated the presence of iNOS mRNA in the majority of astroglial cells, identified by antibody staining to the glial fibrillary acidic protein (GFAP). PCR analysis showed that LPS stimulated synthesis of astrocyte iNOS mRNA, which was detected as early as 2 hr after exposure to LPS, peaked at 4 hr, and slowly declined over the next 20 hr. These results confirm that astrocytes can express iNOS and provide tools for the subsequent analysis of iNOS gene expression in rodent brain © 1994 Wiley‐Liss, Inc.
Peptide bond specificity of calpain: Proteolysis of human myelin basic protein
Authors: Banik N. L. , Chou C.‐H. , Deibler G. E. , Krutzch H. C. , Hogan E. L. 
Published: January 2005

AbstractIn order to determine the peptide bond specificity of calpain, human myelin basic protein (HMBP) was treated with purified calpain of bovine brain. Upon incubation, HMBP component I (HMBP‐1) was degraded into several peptides as demonstrated by sodium dodecy1 sulfate‐polyacrylamide gel electrophoresis. Component I was more susceptible to degradation than components II and III. HMBP degradation products were separated by high performance liquid chromatography (HPLC) and the cleavage sites in HMBP molecules were determined by peptide sequence analysis and by N‐ and C‐terminal analyses. The major cleavage site was found to be 94Val‐95 Thr with several minor cleavages at 49Arg‐50Gly, 18Ala‐19Ser, 23His‐24Ala, 27Gly‐28Phe, 59Asp‐60Ser, 70Gly‐71Ser, 97Arg‐98Thr, 110Ser‐111Leu, 145Asp‐146Ala, and 156Leu‐157Gly. These results indicate that calpain is involved in the limited proteolysis of human myelin basic protein and prolonged incubation causes further digestion of the large peptides. © 1994 Wiley‐Liss, Inc.
Distribution of plectin, an intermediate filament‐associated protein, in the adult rat central nervous system
Authors: Errante L. D. , Wiche G. , Shaw G. 
Published: January 2005

AbstractPlectin is a high molecular weight protein originally identified and characterized as a major cytoskeletal component of the C6 rat glioma cell. Here we demonstrate by immunoblotting of crude intermediate filament (IF) protein preparations that plectin is a cytoskeleton‐associated component of the rat spinal cord. We then used avidin‐biotin peroxidase immunocytochemistry and indirect immunofluorescence to localize plectin within the adult rat central nervous system (CNS) and examine its distribution with respect to IF proteins. Plectin immunoreactivity is localized to all ependymal cells including the choroidal epithelial cells and tanycytes, Bergmann glial processes, radially oriented glial cells in the spinal cord, astrocytes in white matter, a subset of astrocytes in gray matter, a subset of motoneurons in the brainstem and spinal cord, and certain endothelial cells. Colocalization studies with neural If proteins show that plectin has a unique distribution pattern which most closely resembles, but is distinct from, that of vimentin. The few plectin positive neurons invariably also contain the neurofilament triplet proteins and peripherin, so that the ability of plectin to bind to the triplet proteins in vitro may reflect an in vivo interaction. The predominance of plectin at the inner ventricular boundaries of the nervous system as well as at the blood‐brain barrier is in line with the pattern of plectin expression in other tissues and suggests a general role for plectin in the maintenance of such junctional regions. © 1994 Wiley‐Liss, Inc.
Axotomy induces preprotachykinin gene expression in a subpopulation of dorsal root ganglion neurons
Authors: Noguchi K. , Dubner R. , De Leon M. , Senba E. , Ruda M. A. 
Published: January 2005

AbstractThe distribution of dorsal root ganglion (DRG) cell sizes that show changes in preprotachykinin (PPT) gene expression and substance P (SP) levels following axotomy was examined using RNA blot analysis, in situ hybridization histochemistry, and immunocytochemistry. PPT mRNA was induced in medium‐sized (1,000–2,000 μm2) and large‐sized (>2,000 μm2) cells in the DRG after axotomy. There was a 165% increase in the number of labeled cells after sciatic transection and a 260% increase after spinal nerve transection which results in axotomy of all the cells in the ganglion. The further increase after spinal nerve transection suggests that the induction occurred in axotomized neurons. PPT mRNA label was also present in a reduced number of small (<1,000 μm2) cells after axotomy. SP immunoreactivity was also induced in medium‐and large‐sized cells and reduced in small‐sized cells. Our findings suggest that the expression of the PPT gene and SP is differentially regulated in different subpopulations of DRG neurons after axotomy and is consistent with the hypothesis that tachykinins may be important in both sensory transmission and regeneration. © 1994 Wiley‐Liss, Inc.