bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mice expressing the α1B‐adrenergic receptor induces a synucleinopathy with excessive tyrosine nitration but decreased phosphorylation
Authors: Papay Robert , Zuscik Michael J. , Ross Sean A. , Yun June , McCune Dan F. , Gonzalez‐Cabrera Pedro , Gaivin Robert , Wendy B. Macklin  , Drazba Judy , Perez Dianne M. 
Published: March 2003

AbstractWe had previously reported that systemic overexpression of the α1B‐adrenergic receptor (AR) in a transgenic mouse induced a neurodegenerative disease that resembled the parkinsonian‐like syndrome called multiple system atrophy (MSA). We now report that our mouse model has cytoplasmic inclusion bodies that colocalize with oligodendrocytes and neurons, are positive for α‐synuclein and ubiquitin, and therefore may be classified as a synucleinopathy. α‐Synuclein monomers as well as multimers were present in brain extracts from both normal and transgenic mice. However, similar to human MSA and other synucleinopathies, transgenic mice showed an increase in abnormal aggregated forms of α‐synuclein, which also increased its nitrated content with age. However, the same extracts displayed decreased phosphorylation of α‐synuclein. Other traits particular to MSA such as Purkinje cell loss in the cerebellum and degeneration of the intermediolateral cell columns of the spinal cord also exist in our mouse model but differences still exist between them. Interestingly, long‐term therapy with the α1‐AR antagonist, terazosin, resulted in protection against the symptomatic as well as the neurodegeneration and α‐synuclein inclusion body formation, suggesting that signaling of the α1B‐AR is the cause of the pathology. We conclude that overexpression of the α1B‐AR can cause a synucleinopathy similar to other parkinsonian syndromes.
22R‐Hydroxycholesterol protects neuronal cells from β‐amyloid‐induced cytotoxicity by binding to β‐amyloid peptide
Authors: Yao Zhi‐Xing , Brown Rachel C. , Teper Gary , Greeson Janet , Papadopoulos Vassilios 
Published: March 2003

Abstract22R‐hydroxycholesterol, a steroid intermediate in the pathway of pregnenolone formation from cholesterol, was found at lower levels in Alzheimer's disease (AD) hippocampus and frontal cortex tissue specimens compared to age‐matched controls. β‐Amyloid (Aβ) peptide has been shown to be neurotoxic and its presence in brain has been linked to AD pathology. 22R‐hydroxycholesterol was found to protect, in a dose‐dependent manner, against Aβ‐induced rat sympathetic nerve pheochromocytoma (PC12) and differentiated human Ntera2/D1 teratocarcinoma (NT2N) neuron cell death. Other steroids tested were either inactive or acted on rodent neurons only. The effect of 22R‐hydroxycholesterol was found to be stereospecific because its enantiomer 22S‐hydroxycholesterol failed to protect the neurons from Aβ‐induced cell death. Moreover, the effect of 22R‐hydroxycholesterol was specific for Aβ‐induced cell death because it did not protect against glutamate‐induced neurotoxicity. The neuroprotective effect of 22R‐hydroxycholesterol was seen when using Aβ1−42 but not the Aβ25−35 peptide. To investigate the mechanism of action of 22R‐hydroxycholesterol we examined the direct binding of this steroid to Aβ using a novel cholesterol‐protein binding blot assay. Using this method the direct specific binding, under native conditions, of 22R‐hydroxycholesterol to Aβ1−42 and Aβ17−40, but not Aβ25−35, was observed. These data suggest that 22R‐hydroxycholesterol binds to Aβ and the formed 22R‐hydroxycholesterol/Aβ complex is not toxic to rodent and human neurons. We propose that 22R‐hydroxycholesterol offers a new means of neuroprotection against Aβ toxicity by inactivating the peptide.
Effect of tumor necrosis factor‐α converting enzyme (TACE) and metalloprotease inhibitor on amyloid precursor protein metabolism in human neurons
Authors: Blacker Megan , Noe Mark C. , Carty Thomas J. , Goodyer Cynthia G. , LeBlanc Andréa C. 
Published: March 2003

AbstractTumor necrosis factor‐α (TNF‐α) is implicated in inflammatory processes and much effort is being directed at inhibiting the release of TNF‐α for treatment of inflammatory conditions. In this context, the drug CP‐661,631 has been developed to inhibit the TNF‐α converting enzyme (TACE). However, TACE is also implicated in amyloid precursor protein secretion. Amyloid precursor protein (APP) undergoes constitutive and regulated secretion by α‐secretase endoproteolytic cleavage within the amyloid β peptide (Aβ) domain. Alternative cleavage at the N‐ and C‐terminus of the Aβ domain by β‐ and γ‐secretases results in the production of Aβ. In many cellular andin vivoanimal models, increased secretion of APP results in a concomitant decrease in the production of Aβ suggesting that the two pathways are intricately linked. However, in human primary neuron cultures, increased APP secretion is not associated with a decrease in total Aβ production. To determine if the use of CP‐661,631 may enhance amyloidogenic processing in human brain, we have assessed the effect of CP‐661,631 on APP metabolism in primary cultures of human neurons. Our results show that CP‐661,631 effectively prevents regulated APP secretion but does not increase total Aβ levels in human primary neuron cultures.
Induction of heat shock proteins (HSPs) by sodium arsenite in cultured astrocytes and reduction of hydrogen peroxide‐induced cell death
Authors: Fauconneau Bernard , Petegnief Valérie , Sanfeliu Coral , Piriou Alain , Planas Anna M. 
Published: March 2003

AbstractInduction of heat shock proteins (HSPs) protects cells from oxidative injury. Here Hsp72, Hsp27 and heme oxygenase‐1 (HO‐1) were induced in cultured rat astrocytes, and protection against oxidative stress was investigated. Astrocytes were treated with sodium arsenite (20–50 µm) for 1 h, which was non‐toxic to cells, 24 h later they were exposed to 400 µmH2O2for 1 h, and cell death was evaluated at different time points. Arsenite triggered strong induction of HSPs, which was prevented by 1 µg/mL cycloheximide (CXH). H2O2caused cell loss and increased cell death with features of apoptosis, i.e. TdT‐mediated dUTP nick‐end labelling (TUNEL) reaction and caspase‐3 activation. These features were abrogated by pre‐treatment with arsenite, which prevented cell loss and significantly reduced the number of dead cells. The protective effect of arsenite was not detected in the presence of CHX. Pre‐treatment with arsenite increased protein kinase B (Akt) and extracellular signal regulated kinase 1/2 (ERK1/2) phosphorylation after H2O2. However, while Akt phosphorylation was prevented by CHX, Erk1/2 phosphorylation was further enhanced by CHX. The results show that transient arsenite pre‐treatment induces Hsp72, HO‐1 and, to a lesser extent, Hsp27; it reduces H2O2‐induced astrocyte death; and it causes selective activation of Akt following H2O2. It is suggested that HSP expression at the time of H2O2exposure protects astrocytes from oxidative injury and apoptotic cell death by means of pro‐survival Akt.
Overexpression of PrPc triggers caspase 3 activation: potentiation by proteasome inhibitors and blockade by anti‐PrP antibodies
Authors: Paitel E. , Alves da Costa C. , Vilette D. , Grassi J. , Checler F. 
Published: March 2003

AbstractWe examined the influence of cellular prion protein (PrPc) in the control of cell death in stably transfected HEK293 cell line and in the PrPc‐inducible Rov9 cells. PrPc expression in stably transfected HEK293 human cells did not modify basal apoptotic tonus but drastically potentiated staurosporine‐stimulated cellular toxicity and DNA fragmentation as well as caspase 3‐like activity and immunoreactivity. An identical staurosporine‐induced caspase 3 activation was observed after doxycycline in the PrPc‐inducible Rov9 cell line. Interestingly, proteasome inhibitors increase PrPc‐like immunoreactivity and unmasked a basal caspase 3 activation. Conversely, we show that anti‐PrPc antibodies sequestrate PrPc at the cell surface and drastically lower PrPc‐dependent caspase activation. We suggest that intracellular PrPc could sensitize human cells to pro‐apoptotic phenotype and that blockade of PrPc internalization could be a track to prevent intracellular toxicity associated with PrPc overexpression.
Spatial learning deficit in transgenic mice that conditionally over‐express GSK‐3β in the brain but do not form tau filaments
Authors: Hernández Félix , Borrell José , Guaza Carmen , Avila Jesús , Lucas José J. 
Published: March 2003

AbstractDeregulation of glycogen synthase kinase‐3 (GSK‐3) activity in neurones has been postulated as a key feature in Alzheimer's disease (AD) pathogenesis. This was further supported by our recent characterization of transgenic mice that conditionally over‐express GSK‐3β in hippocampal and cortical neurones. These mice, designated Tet/GSK‐3β, showed many of the biochemical and cellular aspects of AD neuropathology such as tau hyperphosphorylation and somatodendritic localization, decreased nuclear β‐catenin, neuronal death and reactive gliosis. Tet/GSK‐3β mice, however, did not show tau filament formation up to the latest tested age of 3 months at least. Here we report spatial learning deficits of Tet/GSK‐3β mice in the Morris water maze. In parallel, we also measured the increase in GSK‐3 activity while further exploring the possibility of tau filament formation in aged mice. We found a significant increase in GSK‐3 activity in the hippocampus of Tet/GSK‐3β mice whereas no tau fibrils could be found even in very old mice. These data reinforce the hypothesis of GSK‐3 deregulation in AD pathogenesis, and suggest that Tet/GSK‐3β mice can be used as an AD model and, most remarkably, can be used to test the therapeutic potential of the selective GSK‐3 inhibitors that are currently under development. Additionally, these experiments suggest that destabilization of microtubules and alteration of intracellular metabolic pathways contribute to AD pathogenesis independent of toxicity triggered by the aberrant tau deposits.
The role of thrombin and thrombin receptors in ischemic, hemorrhagic and traumatic brain injury: deleterious or protective?
Authors: Xi Guohua , Reiser Georg , Keep Richard F. 
Published: March 2003

AbstractIn the last two decades it has become apparent that thrombin has many extravascular effects that are mediated by a family of protease‐activated receptors (PARs). PAR‐1, ‐3 and ‐4 are activated via cleavage by thrombin. The importance of extravascular thrombin in modulating ischemic, hemorrhagic and traumatic injury in brain has recently become clear. Thus, in vitro, thrombin at low concentration protects neurons and astrocytes from cell death caused by a number of different insults. In vivo, pretreating the brain with a low dose of thrombin (thrombin preconditioning), attenuates the brain injury induced by a large dose of thrombin, an intracerebral hemorrhage or by focal cerebral ischemia. Thrombin may also be an important mediator of ischemic preconditioning. In contrast, high doses of thrombin kill neurons and astrocytes in vitro and cause disruption of the blood–brain barrier, brain edema and seizures in vivo. This review examines the role of thrombin in brain injury and the molecular mechanisms and signaling cascades involved.
GABAB receptor mRNA in the raphe nuclei: co‐expression with serotonin transporter and glutamic acid decarboxylase
Authors: Serrats Jordi , Artigas Francesc , Mengod Guadalupe , Cortés Roser 
Published: March 2003

AbstractWe have used double‐label in situ hybridization techniques to examine the cellular localization of GABAB receptor mRNA in relation to serotonin transporter mRNA and glutamic acid decarboxylase mRNA in the rat dorsal raphe, median raphe and raphe magnus nuclei. The degree of cellular co‐localization of these markers notably varied among the different nuclei. In the dorsal raphe, cell bodies showing GABAB receptor mRNA were very abundant, the 85% being also labelled for serotonin transporter mRNA, and a low proportion (5%) showing glutamic acid decarboxylase mRNA. In the median raphe, the level of co‐expression of GABAB receptor mRNA with serotonin transporter mRNA was significantly lower. Some cells were also identified that contained GABAB receptor mRNA in the absence of either one of the other mRNA species studied. Our results support the presence of GABAB receptors in serotonergic as well as GABAergic neurones in the dorsal and median raphe, providing the anatomical basis for the reported dual inhibitory/disinhibitory effect of the GABAB agonist baclofen on serotonergic function.
Expression and functional characterization of the extraneuronal monoamine transporter in normal human astrocytes
Authors: Inazu Masato , Takeda Hiroshi , Matsumiya Teruhiko 
Published: March 2003

AbstractIn this study we examined the functional expression of the extraneuronal monoamine transporter (EMT) in normal human astrocytes (NHA). RT‐PCR with EMT‐specific primers demonstrated the presence of EMT mRNA in NHA. The RT‐PCR products were subjected to restriction‐site analysis using three different enzymes (HinfI, SacI and BclI). The restriction patterns with the three enzymes were identical and were exactly as expected from the known restriction map of human EMT cDNA. DNA sequencing was performed for the RT‐PCR products from NHA. Sequence analysis demonstrated that the sequences of RT‐PCR products were identical to that of EMT. The extract of NHA was immunoblotted with anti‐EMT polyclonal antibody raised against EMT polypeptides. Western blotting indicated that anti‐EMT polyclonal antibody recognized a band of 63 kDa. Immunocytochemical staining using anti‐EMT polyclonal antibody in NHA revealed that the plasma membrane, as well as intracellular, perinuclear compartments, presumably endoplasmic reticulum or Golgi membranes, showed a considerable level of immunoreactivity. We examined the time course of temperature‐dependent [3H]MPP+ uptake in NHA for 60 min. Temperature‐dependent [3H]MPP+ uptake increased in a time‐dependent manner for the initial 45 min and almost reached a plateau level (8.70 ± 0.59 pmol/mg protein) at 60 min. In the presence of 3 µm decynium22 (D22) (the most potent EMT inhibitor), temperature‐dependent [3H]MPP+ uptake was strongly reduced by 61% (3.39 ± 0.76 pmol/mg protein at 60 min). D22‐sensitive [3H]MPP+ uptake was saturable over a MPP+ concentration of 6.25–200 µm. Km for this process was 78.01 ± 7.64 µm and Vmax was 295.4 ± 12.8 pmol/mg protein/min. D22‐sensitive [3H]MPP+ uptake was reduced when the astrocyte membrane potential was depolarized by increasing the concentration of K+ in the uptake buffer or by adding Ba2+ to the uptake buffer. These results provide evidence that the MPP+ transport activity in NHA is potential‐sensitive. Moreover, D22‐sensitive [3H]MPP+ uptake was independent of extracellular Na+. D22‐sensitive [3H]MPP+ uptake was inhibited by D22, various organic cations, steroids and monoamine neurotransmitters. Our results showed that the EMT is functionally expressed in NHA and may also play a key role in the disposition of cationic drugs, neurosteroids, the neurotoxin MPP+ and monoamine neurotransmitters in the brain.
Selective E2F‐dependent gene transcription is controlled by histone deacetylase activity during neuronal apoptosis
Authors: Boutillier Anne‐Laurence , Trinh Emmanuelle , Loeffler Jean‐Philippe 
Published: March 2003

AbstractThe alteration of chromatin through histone acetylation and deacetylation participates in the regulation of gene expression. We have investigated the effects of histone deacetylase inhibition on neuronal fate. We show that treatment of primary neurones with trichostatin A (TSA) or sodium butyrate (NaBu) induces typical features of apoptosis, a cell death that relies on specific genetic programmes. We have further explored the molecular mechanisms implicated in the TSA response and demonstrated that TSA‐induced apoptosis is partly dependent on the activation of the transcription factor E2F‐1, which has pro‐apoptotic functions in these neurones. Furthermore, the increased e2f‐1 transcriptional response is probably the result of mechanisms occurring through E2F‐responsive elements. Histone acetylation also takes place at the e2f‐1 promoter, but this modification is neither required nor by itself sufficient to induce increased transcription at the e2f‐1 promoter. Activation might thus occur through acetylation of non‐histone proteins binding this regulatory element. Finally, we show that TSA induces the transcription of E2F‐dependent genes, such as its cell cycle target cyclin E, but also pro‐apoptotic genes, such as Apaf1. Taken together, our results suggest that, in neuroprotective conditions, histone deacetylase activity allows a constitutive repression of the e2f‐1 gene in mature neurones in order to ensure survival. Deregulation of this repression will ultimately lead to an E2F‐dependent cell death.
Lipid interaction of α‐synuclein during the metal‐catalyzed oxidation in the presence of Cu2+and H2O2
Authors: Lee Eui‐Nam , Lee Sun‐Young , Lee Daekyun , Kim Jongsun , Paik Seung R. 
Published: March 2003

Abstractα‐Synuclein co‐exists with lipids in the Lewy bodies, a pathological hallmark of Parkinson's disease. Molecular interaction between α‐synuclein and lipids has been examined by observing lipid‐induced protein self‐oligomerization in the presence of a chemical coupling reagent ofN‐(ethoxycarbonyl)‐2‐ethoxy‐1,2‐dihydroquinoline. Lipids such as phosphatidic acid, phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine, and even arachidonic acid induced the self‐oligomerization whereas phosphatidylcholine did not affect the protein. Because the oligomerizations occurred from critical micelle concentrations of the lipids, the self interaction of α‐synuclein was shown to be a lipid‐surface dependent phenomenon with head group specificity. By employing β‐synuclein and a C‐terminally truncated α‐synuclein (α‐syn97), the head‐group dependent self‐oligomerization was demonstrated to occur preferentially at the N‐terminal region while the fatty acid interaction leading to the protein self‐association required the presence of the acidic C‐terminus of α‐synuclein. In the presence of Cu2+and H2O2, phosphatidylinositol (PI), along with other acidic lipids, actually enhanced the metal‐catalyzed oxidative self‐oligomerization of α‐synuclein. The dityrosine crosslink formation responsible for the PI‐enhanced covalent self‐oligomerization was more sensitive to variation of copper concentrations than that of H2O2during the metal‐catalyzed oxidation. The enhancement by PI was shown to be due to facilitation of copper localization to the protein because actual binding affinity between copper and α‐synuclein increased fromKdof 44.7 μmto 5.9 μmin the presence of the lipid. Taken together, PI not only affects α‐synuclein to be more self‐interactive by providing the lipid surface, but also enhances the metal‐catalyzed oxidative protein self‐oligomerization by facilitating copper localization to the protein when the metal and H2O2are provided. This observation therefore could be implicated in the formation of Lewy bodies as lipids and metal‐catalyzed oxidative stress have been considered to be a part of pathological causes leading to the neurodegeneration.
Localization of presenilin–nicastrin complexes and γ‐secretase activity to the trans‐Golgi network
Authors: Siman Robert , Velji Jamel 
Published: March 2003

AbstractAbundant biochemical and genetic evidence suggests that presenilins are catalytic components of γ‐secretase, the protease responsible for generating the Alzheimer amyloid β‐protein. However, the differential localization of presenilins to early secretory compartments and γ‐secretase substrates to late secretory compartments and the plasma membrane (the ‘spatial paradox’) argues against this view. We investigated this issue by studying the localization of nicastrin, another putative γ‐secretase component, and its association with presenilin‐1 into proteolytically active complexes. Glycosidase digests revealed that nicastrin exists in multiple glycoforms and is terminally sialylated, a modification often associated with the trans‐Golgi network. Trafficking of nicastrin to the trans‐Golgi network was confirmed by density gradient fractionation and immunofluorescence microscopy. In presenilin‐deficient cells, however, nicastrin trafficking and maturation were abnormal, as the protein was restricted to early secretory compartments and failed to be sialylated. Mature sialylated nicastrin in trans‐Golgi network fractions was complexed quantitatively with N‐ and C‐terminal fragments of presenilin‐1, whereas immature nicastrin present in early secretory compartments was not. Additionally, trans‐Golgi network fractions contained the γ‐secretase substrate β‐amyloid precursor protein C83 and were enriched in presenilin‐dependent γ‐secretase proteolytic activity. The results resolve the apparent spatial paradox by demonstrating that presenilin–nicastrin complexes and presenilin‐dependent γ‐secretase activity are co‐localized to a late secretory compartment. The findings provide further evidence that presenilin‐containing complexes are the γ‐secretase, and indicate that presenilins also regulate γ‐secretase assembly.
Auditing nursing content in patient records
Authors: Ehrenberg Anna , Ehnfors Margareta , Smedby Björn 
Published: March 2003

Auditing nursing content in patient records The objective of this paper is twofold: (a) to explore different approaches in reviewing records based on a literature review of studies of audits of patient records and (b) to apply these approaches on a sample of records to illuminate consequences of their application.The method used was a literature review of papers on recording of nursing care (n=56). Based on our findings, an audit of a stratified sample of records (n=298) from Swedish community health care and nursing homes was performed, applying the different approaches for auditing previously described in the literature.The review showed that audits of patient records were performed using four different approaches with varying aims. The focus of the four approaches can be described as formal structure, process comprehensiveness, knowledge‐based and concordance with actual care. The results of this study suggest that audits of patient records should not be solely limited to encompass the formal structure of recording. To avoid a superficial picture or a false sense of high quality and to obtain a more complete and reliable portrait of the quality of recording, we suggest the process comprehensiveness approach in combination with a critical review of the knowledge base for the assessment, diagnosis and interventions of patient records.