bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early induction of secondary injury factors causing activation of calpain and mitochondria‐mediated neuronal apoptosis following spinal cord injury in rats
Authors: Wingrave J. Michael , Schaecher Kurt E. , Sribnick Eric A. , Wilford Gloria G. , Ray Swapan K. , Hazen‐Martin Debra J. , Hogan Edward L. , Banik Naren L. 
Published: June 2003

AbstractTo investigate a potential relationship between calpain and mitochondrial damage in spinal cord injury (SCI), a 40 gram‐centimeter force (g‐cm) injury was induced in rats by a weight‐drop method and allowed to progress for 4 hr. One‐centimeter segments of spinal cord tissue representing the adjacent rostral, lesion, and adjacent caudal areas were then removed for various analyses. Calcium green 2‐AM staining of the lesion and penumbra sections showed an increase in intracellular free calcium (Ca2+) levels following injury, compared with corresponding tissue sections from sham‐operated (control) animals. Western blot analysis showed increased calpain expression and activity in the lesion and penumbra segments following SCI. Double‐immunofluorescent labeling indicated that increased calpain expression occurred in neurons in injured segments. Western blot analysis also showed an increased Bax:Bcl‐2 ratio, indicating the induction of the mitochondria‐mediated cell death pathway in the lesion and penumbra. The morphology of mitochondria was altered in lesion and penumbra following SCI: mostly hydropic change (swelling) in the lesion, with the penumbra shrunken or normal. At 4 hr after induction of injury, a substantial amount of cytochrome c had been released into the cytoplasm, suggesting a trigger for apoptosis through caspase 3 activation. Neuronal death after 4 hr of injury was detected by a combined TUNEL and double‐immunofluoresence assay in the lesion and penumbra sections of injured cord, compared with sham controls. These results suggest that an early induction of secondary factors is involved in the pathogenesis of SCI. The increased Ca2+ levels could activate calpain and mediate mitochondrial damage leading to neuronal death in lesion and penumbra following injury. Thus, secondary injury processes mediating cell death are induced as early as 4 hr after the injury, and calpain and caspase inhibitors may provide neuroprotection. © 2003 Wiley‐Liss, Inc.
Gene expression profiling of ciliary neurotrophic factor‐overexpressing rat striatal progenitor cells (ST14A) indicates improved stress response during the early stage of differentiation
Authors: Böttcher Tobias , Mix Eilhard , Koczan Dirk , Bauer Peter , Pahnke Jens , Peters Sabine , Weinelt Sabine , Knoblich Rupert , Strauss Ulf , Cattaneo Elena , Thiesen Hans‐Jürgen , Rolfs Arndt 
Published: June 2003

AbstractNeuronal progenitor cells delivering neurotrophic factors are a promising therapeutic tool for treatment of neurodegenerative diseases. Although several promising results have come from studies in different animal models, detailed knowledge of the action of neurotrophic factors in the CNS is still lacking. A clonally derived, immortalized rat striatal cell line (ST14A) expressing ciliary neurotrophic factor (CNTF) offers a stable and controlled background with which to analyze CNTF actions on the transcriptional level in CNS progenitor cells. To identify early transcriptional changes induced by CNTF expression, we transfected the CNTF gene into ST14A cells, which differentiate at the nonpermissive temperature of 39°C via suppression of the immortalizing SV40 large T antigen. This shows a CNTF‐dependent hypoxic/ischemic stress response during the earliest stage of differentiation, with expression of specific transcripts and evidence of translational repression leading to decreased protein synthesis in the transfected cells. This process is mediated by the Ras/MAP kinase pathway and is accompanied by impaired proliferation and metabolism as well as signs of neuronal differentiation. The stress‐like response in the early stage of differentiation improves the ability of the transfected cells to respond to and cope with a stressful environment in vivo. The present data indicate higher viability, longer life, and greater differentiation capacity of CNTF‐ST14A cells if they are used for transplantation. We conclude that the stress‐like response during the early stage of differentiation improves the ability of the CNTF‐ST14A cells to respond and adapt to a stressful environment, which renders them useful candidate cells for in vivo trials of treatment for neurodegenerative diseases in animal models, e.g., of Huntington's disease. © 2003 Wiley‐Liss, Inc.
Altered astrocyte calcium homeostasis and proliferation in theTs65Dn mouse, a model of Down syndrome
Authors: Bambrick Linda L. , Yarowsky Paul J. , Krueger Bruce K. 
Published: June 2003

AbstractGenes from the Down syndrome (DS) critical region of human chromosome 21, which contribute to the pathology of DS, are also found on mouse chromosome 16. Several animal models of DS with triplication of genes from the DS critical region have been generated, including mouse trisomy 16 (Ts16) and a partial trisomic mouse, Ts65Dn. Using computer‐assisted imaging of fura‐2 fluorescence, we found an elevation of intracellular cytoplasmic calcium in cortical astrocytes from neonatal Ts65Dn mouse brain, similar to that observed previously in embryonic Ts16 astrocytes. Furthermore, astrocytes from both Ts65Dn and Ts16 cortex fail to respond to the anti‐proliferative actions of glutamate. These results suggest that defective regulation of cell proliferation and cellular calcium can result from triplication of DS critical region genes. © 2003 Wiley‐Liss, Inc.
Effects of GDNF on 6‐OHDA‐induced death in a dopaminergic cell line: Modulation by inhibitors of PI3 kinase and MEK
Authors: Ugarte Susana D. , Lin Eva , Klann Eric , Zigmond Michael J. , Perez Ruth G. 
Published: June 2003

AbstractParkinson's disease is a neurodegenerative disorder associated with the selective death of dopaminergic neurons. Glial cell line‐derived neurotrophic factor (GDNF) can protect dopaminergic neurons in several parkinsonian models. We used the dopaminergic cell line MN9D to explore the mechanisms underlying GDNF‐mediated protection against the neurotoxin 6‐hydroxydopamine (6‐OHDA). MN9D cell viability was decreased 24 hr after a 15‐min exposure to 6‐OHDA (50–1,000 μM) as revealed by staining with Hoechst reagent and Trypan blue. The addition of GDNF (10 ng/ml) before, during, and after exposure to 6‐OHDA significantly increased the number of viable cells as assessed by Hoechst staining. In contrast, 6‐OHDA‐induced cell membrane damage was unaffected as measured by Trypan blue exclusion. The PI3K specific inhibitor LY294002 (10–50 μM) blocked GDNF‐mediated protection against nuclear condensation, as did the MAPK kinase (MEK) inhibitor U0126 (5– 20 μM). These studies suggest that GDNF can protect dopaminergic cells against some but not all aspects of 6‐OHDA‐induced toxicity by acting through both PI3K and MAPK signaling pathways. © 2003 Wiley‐Liss, Inc.
Hemin induces an iron‐dependent, oxidative injury to human neuron‐like cells
Authors: Goldstein Laurel , Teng Zhi‐Peng , Zeserson Eli , Patel Monica , Regan Raymond F. 
Published: June 2003

AbstractHemin is released from hemoglobin after CNS hemorrhage and is present at high micromolar concentrations in intracranial hematomas. This highly reactive compound is potentially cytotoxic via a variety of oxidative and nonoxidative mechanisms. However, despite its clinical relevance, little is known of its effect on neuronal cells. In this study, we tested the hypotheses that hemin is toxic to human neurons at physiologically relevant concentrations and that its toxicity is iron dependent and oxidative. A homogeneous population of neuron‐like cells was produced by sequential treatment of SH‐SY5Y cells with retinoic acid and brain‐derived neurotrophic factor, using the protocol of Encinas et al. Hemin exposure for 24 hr resulted in cell death that progressively increased between 3 and 30 μM (EC50 approximately 10 μM); protoporphyrin IX, the iron‐free congener of hemin, was not toxic. Cell death commenced at 14 hr and was preceded by a marked increase in cellular reactive oxygen species (ROS). Most injury and ROS production were prevented by concomitant treatment with an equimolar concentration of the lipid‐soluble iron chelator phenanthroline; the water‐soluble chelator deferoxamine was also effective at concentrations of 0.1 mM or higher. Heme oxygenase‐2 was constitutively expressed by these cells, and heme oxygenase‐1 was induced by hemin. Heme oxygenase inhibition attenuated ROS generation and reduced injury by about one‐third. Cell death was also prevented with the sulfhydryl reducing agents glutathione and mercaptoethanol. Nuclear morphology in the hours prior to cell lysis revealed a predominantly homogenous staining pattern; the percentage of fragmented nuclei was increased only at 4 hr and then accounted for only 1.45% ± 0.25% of cells. The general caspase inhibitor zVAD‐fmk had no effect on cell viability. These results suggest that hemin is toxic to human neuron‐like cells at concentrations that are less than 3% of those observed in intracranial hematomas. In this model, its toxicity is iron dependent, oxidative, and predominantly necrotic. © 2003 Wiley‐Liss, Inc.
Insulin‐like growth factor 1 is essential for normal dendritic growth
Authors: Cheng Clara M. , Mervis Ronald F. , Niu Shui‐Lin , Salem Norman , Witters Lee A. , Tseng Victor , Reinhardt Rickey , Bondy Carolyn A. 
Published: June 2003

AbstractThis study evaluated somatic and dendritic growth of neurons in the frontoparietal cortex of Igf1–/– brains. Pyramidal neuron density was increased by ∼25% (P = .005) and soma size reduced by ∼10% (P < .001). Golgi staining revealed that cortical layer II–III neurons exhibited a significant reduction in dendritic length and complexity in Igf1 null mice. Dendritic spine density and presumably synaptic contacts were reduced by 16% (P = .002). Similar findings were obtained for cortical layer V and piriform cortex pyramids. Supporting a reduction in synapses, synaptotagmin levels were reduced by 30% (P < .02) in the Igf1 null brain. Investigation of factors critically involved in dendritic growth and synaptogenesis showed an ∼50% reduction in cortical CDC42 protein expression (P < .001) and an ∼10% reduction in brain cholesterol levels (P < .01) in Igf1 null mice. Evidence is presented that Igf1 deletion causes disruptions in lipid and microtubule metabolism, leading to impaired neuronal somatic and dendritic growth. Published 2003 Wiley‐Liss, Inc.
Two populations of microglial cells isolated from rat primary mixed glial cultures
Authors: Kuwabara Yasuhide , Yokoyama Akiko , Yang Lihua , Toku Kazuko , Mori Kohji , Takeda Ikuko , Shigekawa Takako , Zhang Bo , Maeda Nobuji , Sakanaka Masahiro , Tanaka Junya 
Published: June 2003

AbstractBecause of variations in the morphology and function of microglial cells, it has often been claimed that microglial cells should be classified into two or more subtypes. However, such subtypes have not fully been characterized. In the present study, we isolated microglial cells expressing microglia‐markers CD11b and CD68 from rat mixed glial cultures on the fifth and on the thirteenth days in vitro (DIV 5 and 13) and demonstrate that these two populations of microglial cells have distinct morphology and function. Microglial cells isolated on DIV 5, which we have termed immature cells, are characterized by the presence of large somata, large peroxidase‐ and alkaline phosphatase‐positive granules, and high proliferative activity and suppressed responsiveness to lipopolysaccharide (LPS). In contrast, the microglial cells isolated on DIV 13, which we have termed mature cells, are devoid of granules, appear to be in a state of cell cycle arrest, and respond to LPS by the induction of inducible nitric oxide synthase (iNOS), tumor necrosis factor‐α, and interleukin‐6. Isolated immature cells maintained in pure culture failed to express iNOS in response to LPS. However, if these cells were cultured on astrocyte‐derived extracellular matrix (AsECM) or pure laminin, the cells exhibited an induction of iNOS in response to LPS. AsECM and laminin were also able to induce a state of cell cycle arrest in cultured isolated immature cells. Thus, classification into two types of microglial cells is possible, but both types are in the same cell lineage, because the immature cells can differentiate into mature microglial cells in the presence of laminin or AsECM. Therefore, “microglioblasts” may be the appropriate term for the immature cells. © 2003 Wiley‐Liss, Inc.
Expression of Foxp2, a gene involved in speech and language, in the developing and adult striatum
Authors: Takahashi Kaoru , Liu Fu‐Chin , Hirokawa Katsuiku , Takahashi Hiroshi 
Published: June 2003

AbstractMany members of the forkhead/winged helix transcriptional factors are known to be regulators of embryogenesis. Mutations of the Fox gene family have been implicated in a range of human developmental disorders. Foxp2, a member of the Fox gene family, has recently been identified as the first gene that is linked to an inherited form of language and speech disorder. To elucidate the anatomical basis of language processing in the brain, we have examined the expression pattern of Foxp2 gene and its homologous gene, Foxp1, in the rat brain through development. Expression of Foxp2 mRNA was detected in the ventral telencephalon as early as embryonic day 13. Foxp2 mRNA was expressed primarily in differentiated cells of the lateral ganglionic eminence (striatal primordium). Of particular interest was that the developmental expression of Foxp2 followed a compartmetnal order in the striatum. Patches containing high levels of Foxp2 were aligned with patches enriched in mu‐opoid receptor, a marker for striosomal cells, in the striatum through postnatal development. Conversely, Foxp2‐positive patches were devoid of calbindin‐D28k, a maker for striatal matrix cells. Therefore, Foxp2 was preferentially expressed in striosomal compartment in the striatum during development. In the mature striatum, Foxp2 expression was maintained in striosomes, although its expression level was reduced. In contrast to Foxp2, Foxp1 was expressed in both the striosomal and matrix compartments in the striatum through development. The striatum is known to be involved in the process of procedural memory, and mutation of Foxp2 results in neurological disorders of language and speech. Given the preferential expression of Foxp2 in the striosomal compartment, the striatum, particularly the striosomal system, may participate in neural information processing for language and speech. Our suggestion is consistent with the declarative/procedural model proposed by Ullman and colleagues (Ullman et al. [1997] J. Cogn. Neurosci. 9:266–276; Ullman [2001] Nat. Rev. Neurosci. 2:717–726), in which the procedural memory‐dependent mental grammar is rooted in the basal ganglia and the frontal cortex and the declarative memory‐dependent mental lexicon is rooted in the temporal lobe. © 2003 Wiley‐Liss, Inc.
Cloning and expression of the rat BACE1 promoter
Authors: Lange‐Dohna Christine , Zeitschel Ulrike , Gaunitz Frank , Perez‐Polo J. Regino , Bigl Volker , Roßner Steffen 
Published: June 2003

AbstractThe pathogenic processing of the amyloid precursor protein (APP) into β‐amyloid peptides, which give rise to β‐amyloid plaques in the brains of Alzheimer's disease patients, requires the enzymatic activity of the beta‐site APP‐cleaving enzyme 1 (BACE1). We report the cloning and sequence of a 1.5‐kb DNA fragment upstream of the coding sequence of the rat BACE1 gene and the construction of a BACE1 promoter/luciferase reporter construct. The basal activity of this promoter construct was highest in neuronal cell lines such as BE(2)‐C and PC12 and in the pancreatic cell line AR42J, somewhat lower in rat primary neurons, and astrocytic and microglial cultures, very low in hepatocytes, and almost absent in fibroblasts and in the monocyte‐macrophage cell line RAW264.7. The first 600 bp of this promoter are highly conserved among rat, mouse, and human, suggesting that this region contains regulatory elements that modulate BACE1 transcription. Indeed, this fragment contains several putative transcription factor binding sites such as MZF1, Sp1, four GATA‐1 sites, and one YY1 site. Directed mutagenesis of GATA‐1 elements led to altered luciferase expression, indicating that these sites are involved in the regulation of BACE1 transcription. Additionally, the analysis of promoter activities of deletion mutants suggests the presence of activators of BACE1 transcription between bases −514 to −753 and of suppressor elements between bases −754 and −1541. The BACE1 promoter sequence data and the constructs described here will be useful to identify factors that influence the expression of BACE1 in experimental paradigms in vitro. © 2003 Wiley‐Liss, Inc.
Spontaneous central nervous system remyelination is not altered in NFH‐lacZ transgenic mice after chemical demyelination
Authors: Jean Isabelle , Fressinaud Catherine 
Published: June 2003

AbstractHarmonious functioning of the nervous system depends on neuron–glia interactions, particularly between the axons and their myelinating cells, i.e., oligodendrocytes (OL) in the central nervous system (CNS). In human demyelinating diseases such as multiple sclerosis (MS), demyelination may be associated with axonal damage, but alterations of the axonal cytoskeleton, which is composed mainly of neurofilaments (NF) and microtubules, are largely unknown, as are the consequences on remyelination. In a model of demyelination induced by lysophosphatidylcholine (LPC), we have shown that demyelination was correlated with a decrease in NF immunolabelling, and that these axonal abnormalities were reduced by platelet‐derived growth factor (PDGF)‐enhanced remyelination in adult rats. We have analysed the spontaneous remyelination after LPC stereotaxic injection in the CNS of transgenic NFH‐lacZ mice, which present axonal atrophy caused by abnormal distribution of NF, associated with hypermyelination in the PNS, and normal myelin thickness in the CNS. Axonal atrophy in the CNS of NFH‐lacZ mice was confirmed, but it was not worsened by demyelination. On the contrary, demyelination induced axonal atrophy in wild‐type mice, demonstrating that NF are essential for axonal calibre determination. Moreover, an efficient spontaneous remyelination occurred in NFH‐lacZ as well as in wild‐type mice, indicating that the NF are not necessary for CNS remyelination. These findings point out that NF modifications observed in MS may not be responsible for the lack of remyelination in this disease. © 2003 Wiley‐Liss, Inc.
Regulation of CNS glial phenotypes in N20.1 cells
Authors: Studzinski Diane M. , Benjamins Joyce A. 
Published: June 2003

AbstractThe N20.1 oligodendroglial cell line, immortalized with SV40 T antigen, simultaneously expresses oligodendroglial markers and glial fibrillary acidic protein (GFAP), an astroglial marker. This study examines the plasticity of N20.1 cells with regard to GFAP expression, and its relationship to expression of SV40 T antigen, p53, and a novel nuclear antigen detected by the A007 monoclonal antibody. Marked changes occur in GFAP levels and cell morphology when N20.1 cells are switched from the permissive temperature (34°C) to the non‐permissive temperature (39°C), and with cyclic AMP elevation at 39°C. At 34°C, levels of GFAP are high; when cells are switched to 39°C, GFAP levels decrease significantly, then increase slightly when forskolin is added. At both temperatures, the cells display feathery GFAP immunostaining. When forskolin is added at 39°C, however, cells display bright fibrous GFAP staining in elongated processes. The changes in GFAP were compared to changes in T antigen and p53. As expected, the decrease in T antigen at 39°C was accompanied by movement of p53 from the nucleus to cytoplasm. Total p53 levels did not change, however, and forskolin did not alter the respective distribution or levels of p53 at either temperature. At both temperatures, the cell bodies and processes show internal expression of sulfatide, as demonstrated with the O4, Sulph I, and A007 antibodies. We show, for the first time, abundant nuclear immunoreactivity with the A007 monoclonal antibody in the N20.1 cells. This nuclear reactivity is seen at 34°C, but not at 39°C, similar to p53, and is not detected with the other sulfatide antibodies. Double‐label immunostaining shows that the nuclear A007 immunoreactivity is co‐localized in nuclear structures with T antigen and p53 at 34°C, but is not found in every nucleus containing these antigens. We conclude that regulation of GFAP expression and morphology in N20.1 cells is dependent on a combination of T antigen expression and level of cAMP and may be related to regulation of p53 and the A007 nuclear antigen. © 2003 Wiley‐Liss, Inc.
Fractalkine protein localization and gene expression in mouse brain
Authors: Tarozzo G. , Bortolazzi S. , Crochemore C. , Chen S.‐C. , Lira A.S. , Abrams J.S. , Beltramo M. 
Published: June 2003

AbstractFew chemokines are expressed constitutively in the brain at detectable levels; amongst them is fractalkine. We analyzed the distribution of fractalkine in the mouse brain with the aim of giving a neuroanatomical support to the study of its physiological function. To this end, we carried out an analysis of fractalkine protein localization and gene expression. An anti‐fractalkine antibody was produced and used to perform an immunohistochemical study. The results indicated a high level of fractalkine protein in cortex, hippocampus, basal ganglia, and olfactory bulb. In particular, the presence of abundant immunoreactive neurons was observed in layers II, III, V, and VI of the cortex. In the hippocampus, the CA1 region was the most intensely labeled, but immunoreactive neurons were present also in CA2 and CA3, whereas in the basal ganglia, immunoreactive cells were observed in the caudate putamen. Other brain structures such as the brainstem showed a few scattered immunoreactive cells. The presence of fractalkine immunoreactive fibers was revealed only in the olfactory bulb and in the anterior olfactory nuclei. Gene expression study results, obtained by both semiquantitative PCR and in situ hybridization, matched protein localization with the highest levels of fractalkine transcript detected in the hippocampus, cortex, and striatum. The present study showed that fractalkine protein and mRNA are constitutively expressed at a high level in forebrain structure, but are almost absent in the hindbrain. Furthermore, localization at the cellular body level would suggest a paracrine or cell‐to‐cell interaction role for fractalkine more than a neurotransmission modulatory function. © 2003 Wiley‐Liss, Inc.
Structural Characterization and Degradability of Poly(L‐lactic acid)s Incorporating Phenyl‐Substituted α‐Hydroxy Acids as Comonomers
Authors: Moon Sung‐Il , Urayama Hiroshi , Kimura Yoshiharu 
Published: June 2003

AbstractThree types of copolymers of poly(L‐lactic acid) (PLLA) were synthesized by direct polycondensation of L‐lactic acid and phenyl‐substituted α‐hydroxy acids (L‐phenyllactic acid and D‐ and L‐mandelic acids). It was found that the glass transition temperature of the copolymers comprising L‐mandelic acid became significantly higher (from 58 to 69 °C) with increasing content of L‐mandelic acid (from 0 to 50 mol‐%) although the Mw decreased (from 87 000 to 4 000 Da). The cast films of the L‐mandelic acid containing copolymers showed improved tensile properties compared with those of the PLLA film. This may be due to a pinning effect of the L‐mandelic acid units on the helix formation of PLLA, although 30% of the units were racemized. The enzymatic degradability of the L‐mandelic acid containing copolymers was much higher than that of PLLA, as analyzed with Proteinase K® originating from Tritirachium album.Synthesis of copolymers of L‐lactic acid and phenyl‐substituted α‐hydroxy acids.magnified imageSynthesis of copolymers of L‐lactic acid and phenyl‐substituted α‐hydroxy acids.