bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leukemia inhibitory factor mRNA expression is upregulated in macrophages and olfactory receptor neurons after target ablation
Authors: Getchell Thomas V. , Shah Dharmen S. , Partin James V. , Subhedar Nishikant K. , Getchell Marilyn L. 
Published: August 2002

AbstractAfter target ablation by olfactory bulbectomy (OBX), the murine olfactory epithelium (OE) undergoes degenerative changes leading to apoptosis of olfactory receptor neurons (ORNs) followed by regenerative changes that include proliferation of progenitor cells leading to neurogenesis and ORN replacement. Macrophages recruited to the OE after OBX are involved in both the degenerative and regenerative processes. Relative quantitative RT‐PCR was used to demonstrate that within hours of OBX, mRNAs encoding three key components in the leukemia inhibitory factor (LIF) signaling pathway, including LIF, LIF receptor (LIFR), and STAT3, as well as cyclin D1, a growth factor sensor indicative of progenitor cell transformation, were upregulated. These mRNAs reached peak levels of expression on or before day 3 post‐OBX, coincident with the peak time for macrophage recruitment and progenitor cell proliferation. Cells expressing LIF mRNA in the OE of mice at 3 days post‐OBX, the time point at which LIF mRNA expression peaked, were identified using non‐isotopic in situ hybridization. LIF mRNA was localized in infiltrating macrophages; near‐adjacent sections exhibited macrophages immunoreactive for F4/80, a marker for activated macrophages, in numbers commensurate with those expressing LIF mRNA. LIF mRNA was also localized in surviving ORNs, identified by their expression of olfactory marker protein (OMP) mRNA and protein in near‐adjacent sections. Our data suggest that LIF functions as a mitogen originating from recruited macrophages through an intercellular signaling pathway that stimulates proliferation of progenitor cells leading to neurogenesis and regeneration, and as an intracellular survival factor for traumatized ORNs. © 2002 Wiley‐Liss, Inc.
Effects of IL‐1β, IL‐6 or LIF on rat sensory neurons co‐cultured with fibroblast‐like cells
Authors: Edoff Karin , Jerregård Helena 
Published: August 2002

AbstractInflammation may affect the local presence of sensory nerve fibers in situ and inflammatory mediators influence sensory neurons in vitro. In the present study we have investigated effects of the cytokines interleukin‐1β (IL‐1β, interleukin‐6 (IL‐6), and leukemia inhibitory factor (LIF) on survival of and neurite growth from neonatal rat sensory neurons co‐cultured with fibroblast‐like cells prepared from neonatal rat skin (sFLCs) or perichondrium (pFLCs). The results showed that both FLC types expressed receptors for all three cytokines. Five ng/ml of either cytokine, but not lower or higher concentrations, supported survival of DRG neurons co‐cultured with sFLCs. Neuronal survival was also enhanced by addition of the soluble IL‐6 receptor (rsIL‐6R) with or without IL‐6. In co‐cultures with pFLCs neuronal survival was promoted by IL‐6, increasing with cytokine concentration. Addition of rsIL‐6R without IL‐6 did also stimulate neuronal survival. The growth of neurites from DRG neurons co‐cultured with sFLCs was stimulated by 0.5 ng/ml LIF, unaffected by 5 ng/ml LIF and inhibited by 50 ng/ml LIF. Considering DRG neurons co‐cultured with pFLCs, 50 ng/ml of either of the three cytokines, as well as rsIL‐6R conditioned medium, stimulated neurite outgrowth. Some of the cytokine effects observed were reduced by application of antibodies against nerve growth factor (NGF). We conclude that that the cytokines examined affect DRG neurons in terms of survival or neuritogenesis, that the effects are influenced by cytokine concentration and the origin of the FLCs and that some of the effects are indirect, probably being mediated by factors released from FLCs. © 2002 Wiley‐Liss, Inc.
Pre‐ and postsynaptic maturation of the neuromuscular junction during neonatal synapse elimination depends on protein kinase C
Authors: Lanuza Maria A. , Garcia Neus , Santafé Manel , González Carmen M. , Alonso Immaculada , Nelson Phillip G. , Tomàs Josep 
Published: August 2002

AbstractThe distribution of acetylcholine receptors (AChRs) within and around the neuromuscular junction changes dramatically during the first postnatal weeks, a period during which polyneuronal innervation is eliminated. We reported previously that protein kinase C (PKC) activation accelerates postnatal synapse loss. Because of the close relationship between axonal retraction and AChR cluster dispersal, we hypothesize that PKC can modulate morphological maturation changes of the AChR clusters in the postsynaptic membrane during neonatal axonal reduction. We applied substances affecting PKC activity to the neonatal rat levator auris longus muscle in vivo. Muscles were then stained immunohistochemically to detect both AChRs and axons. We found that, during the first postnatal days of normal development, substantial axonal loss preceded the formation of areas in synaptic sites that were free of AChRs, implying that axonal loss could occur independently of changes in AChR cluster organization. Nevertheless, there was a close relationship between axonal loss and AChR organization; PKC modulates both, although differently. Block of PKC activity with calphostin C prevented both AChR loss and axonal loss between postnatal days 4 and 6. PKC may act primarily to influence AChR clusters and not axons, insofar as phorbol ester activation of PKC accelerated changes in receptor aggregates but produced relatively little axon loss. © 2002 Wiley‐Liss, Inc.
Varied actions of proinflammatory cytokines on excitotoxic cell death in the rat central nervous system
Authors: Allan Stuart M. 
Published: August 2002

AbstractInterleukin (IL)‐1β mediates diverse forms of neurodegeneration and exacerbates cell death induced by striatal injection of the excitotoxin α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA) in the rat brain. The objective of this study was to determine whether this effect was specific to IL‐1β. Injection of IL‐1α and AMPA in the striatum had effects identical to those of IL‐1β, whereas coinjection of IL‐6 or tumor necrosis factor (TNF)‐α with AMPA failed to induce significant cortical cell death. In contrast to IL‐1α, IL‐1β, and IL‐6, TNFα significantly reduced (by 38%) the local striatal damage. These findings suggest that the effect of IL‐1 on AMPA receptor‐mediated cell death in the rat striatum is not mimicked by other proinflammatory cytokines. Furthermore, TNFα shows neuroprotective effects against acute excitotoxic injury. © 2002 Wiley‐Liss, Inc.
Participation of structural microtubule‐associated proteins (MAPs) in the development of neuronal polarity
Authors: González‐Billault C. , Engelke M. , Jiménez‐Mateos E.M. , Wandosell F. , Cáceres A. , Avila J. 
Published: August 2002

AbstractSeveral lines of evidence have indicated that changes in the structure of neuronal cytoskeleton provide the support for the dramatic morphological changes that occur during neuronal differentiation. It has been proposed that microtubule‐associated proteins can contribute to the development of this phenomenon by controlling the dynamic properties of microtubules. In this report we have characterized the effect of the combined suppression of MAP1B and tau, and MAP1B and MAP2 on neuronal polarization in cultured hippocampal cells grown on a laminin‐containing substrate. We have taken advantage of the use of a mouse line deficient in MAP1B expression obtained by the gene trapping approach. In addition to this engineered mice line we used the antisense oligonucleotide approach to induce the suppression of tau or MAP2, in wild type and MAP1B‐deficient neurons. Together these results show a synergistic role for MAP1B/MAP2 and MAP1B/TAU. © 2002 Wiley‐Liss, Inc.
Cerebrospinal fluid neurofilament and glial fibrillary acidic protein in patients with cerebral vasculitis
Authors: Nylén K. , Karlsson J‐E. , Blomstrand C. , Tarkowski A. , Trysberg E. , Rosengren L.E. 
Published: August 2002

AbstractFew diseases in clinical medicine cause as much diagnostic consternation as central nervous system (CNS) vasculitis because of its varying modes of presentation and frequently overlapping clinical and pathological features. There are no pathognomonic clinical or laboratory findings. The purpose of the present retrospective study was to validate the use of the light subunit of neurofilament triplet protein (NFL) and glial fibrillary acidic protein (GFAP) as markers of CNS tissue damage for patients with systemic or isolated CNS vasculitis. Levels of cerebrospinal fluid (CSF) NFL and GFAP were measured using ELISAs. Both CSF NFL and CSF GFAP concentrations were significantly higher in a patient group diagnosed with CNS vasculitis (P < 0.01 and P < 0.05, respectively) than in a patient group for whom CNS vasculitis was excluded. In the future, analysis of CSF NFL in particular, but also GFAP, may be a useful complement in the difficult clinical task of diagnosing CNS vasculitis. © 2002 Wiley‐Liss, Inc.
Temporal analysis of cytokine gene expression during infiltration of porcine neuronal grafts implanted into the rat brain
Authors: Melchior Benoît , Rémy Séverine , Nerrière‐Daguin Véronique , Heslan Jean‐Marie , Soulillou Jean‐Paul , Brachet Philippe 
Published: August 2002

AbstractA large array of evidence supports the involvement of infiltrating T lymphocytes in the rejection process of intracerebral neuronal xenografts. Little is known, however, about the molecular mechanisms that drive the recruitment of this cell type. In the present work, we used real‐time RT‐PCR methodology to investigate the kinetics of cytokine gene expression during the infiltration of fetal porcine neurons (PNEU) implanted into the striatum of LEW.1A rats. T lymphocyte infiltration was followed by measuring the intracerebral levels of transcripts encoding the β chain of the T cell receptor. These transcripts remained barely detectable until the fourth week (28 days) postimplantation, when a sudden accumulation occurred. Their kinetics, which support previous immunohistochemical observations, indicate that αβT lymphocyte recruitment occurs rapidly after a delay of several weeks in this experimental model. Infiltration of PNEU grafts by T lymphocytes was accompanied by a concomitant, dramatic augmentation of transcripts coding for monocyte chemotactic protein‐1 and RANTES (for regulated on activation, normal T cell expressed and secreted), two chemokines targeting this cell type, among others. Likewise, a sudden accumulation of transcripts of proinflammatory lymphokines [interleukin (IL)‐1α, tumor necrosis factor‐α, IL‐6] as well as Th1 cytokines (IL‐2, interferon‐γ) was also detected. In contrast, IL‐4, ‐10, and ‐13 mRNA remained barely detectable at the different time points. No significant changes were noticed for IL‐12 or transforming growth factor‐β transcripts. These data support the concept that T lymphocyte infiltration of PNEU grafts is actively promoted by a local production of chemokines and proinflammatory lymphokines and is based on a Th1 polarization. © 2002 Wiley‐Liss, Inc.
Characterization of astrocytes derived from human NTera‐2/D1 embryonal carcinoma cells
Authors: Sandhu Jagdeep K. , Sikorska Marianna , Walker P. Roy 
Published: August 2002

AbstractAstrocytes are the predominant cell type in the vicinity of glutamatergic synapses, where they monitor and maintain low levels of glutamate. Synaptic homeostasis of glutamate involves its removal from the synaptic cleft via high‐affinity glutamate transporters, glutamate transporter‐1 (GLT‐1)/excitatory amino acid transporters (EAAT)2 and glutamate and aspartate transporter (GLAST)/EAAT1, and glutamate‐catabolizing enzyme, glutamine synthase. Glutamate transporters have been mostly characterized in rodent astrocytes, due to the lack of a convenient human cell system. We report here that NTera‐2 (NT2/D1, a cell line derived from a human teratocarcinoma and known to differentiate into neurons) can also be differentiated by a 4‐week treatment with retinoic acid into functional astrocytes (NT2/A). Differentiation was accompanied by decreased cell proliferation and cell‐cycle arrest, as measured by flow cytometry, immunostaining for Ki67 and incorporation of 5‐bromo‐2′deoxyuridine (BrdU). Immunocytochemistry and Western blot analysis showed that NT2/A expressed glial fibrillary acidic protein, vimentin and S100β. Reverse transcription polymerase chain reaction (PCR) detected mRNA encoding glutamate transporters GLT‐1/EAAT2 and GLAST/EAAT1. The expression level of GLAST/EAAT1 was higher than that of GLT‐1/EAAT2, which is a typical expression pattern for primary astrocytes. Functionality of the transporters was demonstrated by the uptake of 3H‐glutamate. NT2/A also expressed active glutamine synthase, and treatment with glutamate (up to 1 mM for 24 hr) was non‐toxic, suggesting that these cells were capable of converting it to non‐toxic metabolites. NT2/A and NT2‐derived neurons could be grown as mixed cultures and this may prove to be a useful experimental model to study molecular mechanisms underlying glutamate excitotoxicity. © 2002 Government of Canada. Exclusive worldwide publication rights in the article have been transferred to Wiley‐Liss, Inc.
L‐Serine regulates the activities of microglial cells that express very low level of 3‐phosphoglycerate dehydrogenase, an enzyme for L‐serine biosynthesis
Authors: Sugishita Hiroki , Kuwabara Yasuhide , Toku Kazuko , Doi Lisa , Yang Lihua , Mitoma Junya , Furuya Shigeki , Hirabayashi Yoshio , Maeda Nobuji , Sakanaka Masahiro , Tanaka Junya 
Published: August 2002

AbstractMicroglia are well known to become activated during various kinds of neuropathological events. The factors that are responsible for the activation, however, are not fully determined. In the present study, L‐Ser was shown to enhance production of nitric oxide (NO), interleukin‐6 (IL‐6) and tumor necrosis factor α (TNF α) by lipopolysaccharide (LPS)‐stimulated cultured rat microglial cells. L‐Ser, however, did not enhance the expression of mRNAs encoding inducible NO synthase, IL‐6 and TNF α. On the other hand, astrocytes did not depend on L‐Ser for release of IL‐6 and TNF α. The expression of an enzyme 3‐phosphoglycerate dehydrogenase (3PGDH), which is essential for L‐Ser biosynthesis from a glycolytic intermediate 3‐phosphoglycerate, was investigated. As revealed by Western blotting and immunocytochemical staining, 3PGDH‐protein expression in vitro was the highest in astrocytes, intermediate in neurons and the lowest in microglial cells. Semiquantitative RT‐PCR showed that microglial cells expressed 3PGDH‐mRNA at a lower level than astrocytes. In frozen sections from rat forebrain, only astrocytes were immunoreactive for 3PGDH. The present study suggested that L‐Ser is able to modulate microglial function mainly at the translation level because microglial cells cannot synthesize sufficient amount of L‐Ser due to the scarce expression of 3PGDH. J. Neurosci. Res. 64:392–401, 2001. © 2001 Wiley‐Liss, Inc.
Constitutive expression and delayed light response of casein kinase Iϵ and Iδ mRNAs in the mouse suprachiasmatic nucleus
Authors: Ishida Yoshiki , Yagita Kazuhiro , Fukuyama Tsuyoshi , Nishimura Masataka , Nagano Mamoru , Shigeyoshi Yasufumi , Yamaguchi Shun , Komori Takahide , Okamura Hitoshi 
Published: August 2002

AbstractCasein kinase Iϵ (CKIϵ) and casein kinase Iδ (CKIδ) phosphorylate clock oscillating mPER proteins, and play a key role in the transcription (post)translation feedback loop that generates circadian rhythm. In the present study, the expression profiles of CKIϵ and CKIδ mRNAs were examined in the mice clock center, suprachiasmatic nucleus (SCN). Moderate levels of CKIϵ and CKIδ mRNAs were constantly expressed in the SCN in both light:dark and constant dark conditions. This finding supports the hypothesis that CKI may form a constant threshold to the nuclear entry of mPER proteins as in the Drosophila homologue, double‐time. Further, we demonstrated that the light exposure at subjective night induced a delayed increase in CKIϵ and CKIδ mRNAs in the SCN. CKIϵ and CKIδ proteins may play a role on light‐induced phase‐shift. J. Neurosci. Res. 64:612–616, 2001. © 2001 Wiley‐Liss, Inc.
Changes in gene expression following induction of ischemic tolerance in rat brain: Detection and verification
Authors: Wrang Maria L. , Møller Flemming , Alsbo Carsten W. , Diemer Nils H. 
Published: August 2002

AbstractTolerance against ischemic insults can be elicited in the CA1 region of rat hippocampus by inducing a short ischemic period 2–3 days prior to the ischemic insult. To detect genes whose expression changes following induction of ischemic tolerance (IT), we applied a differential display technique called restriction fragment differential display‐PCR (RFDD‐PCR). RFDD‐PCR displays the coding region of mRNA and allows detection of differentially expressed mRNA. Double‐stranded cDNA generated using a T25V primer is digested by the endonuclease TaqI, and adapters are ligated onto the cDNA fragments. When amplifying the adapter‐containing cDNA fragments under high‐stringency conditions, reproducible PCR profiles are obtained. By comparing these profiles from naïve and ischemia‐tolerant rat brains statistically, significant expression changes of 20 fragments were identified. To verify the observed changes, quantitative PCR and in situ hybridization were performed for three fragments representing proteins with quite different functions (GluR2‐flop, SC1, and p68 RNA helicase). Quantitative PCR displayed the same degree of regulation as RFDD‐PCR, but in situ hybridization did not display any regulation. As the applied PCR‐based techniques detect only polyadenylated mRNA, whereas in situ hybridization detects both nonadenylated and adenylated mRNA, changes in the polyadenylation state of the mRNA, rather than inconsistent changes in the total amount of mRNA, probably explain this discrepancy. Thus, our results show that the expression of genes hitherto not related to IT changes with the induction of IT and that the degree of regulation displayed by RFDD‐PCR can be verified by quantitative PCR. J. Neurosci. Res. 65:54–58, 2001. © 2001 Wiley‐Liss, Inc.
Expression of small heat shock proteins and intermediate filaments in the human optic nerve head astrocytes exposed to elevated hydrostatic pressure in vitro
Authors: Salvador‐Silva Mercedes , Ricard Cynthia S. , Agapova Olga A. , Yang Ping , Hernandez M. Rosario 
Published: August 2002

AbstractThe small heat shock proteins (sHSP), αB‐crystallin and Hsp27 are chaperone molecules that maintain the integrity of intermediate filament (IF) network and prevent unfolding of cellular proteins induced by stress. In the optic nerve head (ONH) of eyes with glaucoma, reactive astrocytes expressed Hsp27, perhaps in response to stress related to elevated intraocular pressure. In this study, we determined the effect of elevated hydrostatic pressure (HP) in the synthesis, distribution and co‐localization of αB‐crystallin and Hsp27 with IF in cultured ONH astrocytes. Astrocyte monolayers were pressurized to 60 mm Hg (92% air 8% CO2) and incubated at 37°C for 6, 24 or 48 hr. Controls were exposed to ambient pressure. Cells were analyzed by immunocytochemistry, Western blot and immunoprecipitation using antibodies to Hsp27, αB‐crystallin, vimentin or GFAP. Control astrocytes seemed flat, polygonal with short processes. αB‐crystallin appeared granular in the perinuclear area and filamentous in the cell periphery. Fine granular Hsp27 was distributed throughout the cytoplasm. GFAP and vimentin co‐localized with Hsp27 in the cytoplasm. Astrocytes exposed to HP were star‐shaped with long processes. Hsp27 was condensed in large granules around the nucleus. GFAP and vimentin co‐localized with Hsp27 and αB‐crystallin in the perinuclear area. Western blot and metabolic labeling detected increased synthesis of Hsp27, GFAP and vimentin but no change in αB‐crystallin. These results indicated that GFAP and vimentin associate with Hsp27 and αB‐crystallin in ONH astrocytes. HP affected the integrity of the cytoskeleton consistent with morphological changes. Small HSP may reinforce and maintain IF integrity in response to HP. J. Neurosci. Res. 66:59–73, 2001. © 2001 Wiley‐Liss, Inc.
Excitation of the pedunculopontine tegmental NMDA receptors induces wakefulness and cortical activation in the rat
Authors: Datta Subimal , Patterson Elissa H. , Spoley Eric E. 
Published: August 2002

AbstractMicroinjection of the excitatory amino acid, L‐glutamate into the brainstem pedunculo pontine tegmentum (PPT) has been shown to induce wakefulness, however, it has been unclear that receptors mediate this effect. The aim of this study was to test the hypothesis that in the PPT, L‐glutamate induces cortical activation and wakefulness via activation of NMDA receptors. To test this hypothesis, three sets of micro‐injections into the PPT were carried out on two different groups of rats that were then allowed to move freely although chronic instrumentation recorded sleep/wake states. Three days after the initial control injections of saline, in a contra‐lateral site, Group I was micro‐injected with saline + glutamate (saline first, and glutamate 15 min later); after another 3 days, the same rats were micro‐injected with the NMDA‐receptor‐specific antagonist, 2‐amino‐5‐phosphonopentanoic acid, (AP5) + glutamate. Group II received the same initial control injections (saline only), then AP5 + glutamate and the saline + glutamate micro‐injections last. In rats that were not pretreated with AP5, microinjection of a 90 ng dose of L‐glutamate (0.48 nmol in a volume of 0.1 μl vehicle) kept animals awake for 2–3 hr by eliminating both slow‐wave sleep (SWS) and rapid eye movement (REM) sleep. These behavioral state changes were accompanied by concomitant increase in the power of gamma (γ) frequency (20–60 Hz) waves in the cortical EEG. Pretreatment of L‐glutamate injection sites with 0.48 nmol of AP5 blocked L‐glutamate‐induced‐wakefulness and preserved a normal amount of wakefulness and sleep. Pretreatment with AP5 decreased the power of γ‐wave activity below its control level. These results support the hypothesis that the glutamate‐induced‐wakefulness and cortical activation effects are mediated via the NMDA receptors. J. Neurosci. Res. 66:109–116, 2001. © 2001 Wiley‐Liss, Inc.