bluuebunny/crossref_metadata_2025_split huggingface dataset:
F‐spondin plays a critical role in murine neuroblastoma survival by maintaining IL‐6 expression
Authors: Cheng Yung‐Chih , Liang Chi‐Ming , Chen Yen‐Po , Tsai Inn‐Ho , Kuo Cheng‐Chin , Liang Shu‐Mei 
Published: June 2009

AbstractF‐spondin is associated with the regulation of axonal growth and the development of the nervous system. Its mechanism of action, however, is not clearly understood. In this study, we found that murine neuroblastoma Neuro‐2a cells expressed a significant level of IL‐6, but only trace amounts of IL‐12, tumor necrosis factor α and nitric oxide. Knock‐down of F‐spondin mRNA in murine neuroblastoma NB41A3 and Neuro‐2a cells using small interfering RNAs led to decreased IL‐6 levels along with lower resistance to serum starvation and cytotoxic amyloid β1–42 (Aβ1–42) peptide. Restoring decline of F‐spondin or IL‐6 induced by F‐spondin knock‐down through adding exogenous F‐spondin, IL‐6 or over‐expressing F‐spondin reversed the cell death induced by Aβ1–42 peptide or serum starvation. The decrease of IL‐6 level was positively correlated with decrease of NF‐κB and inhibition of p38 mitogen‐activated protein kinase (MAPK). Over‐expressing MEKK, a kinase activator of the p38 MAPK pathway, increased IL‐6 production, restored the decrease of p38 induced by F‐spondin knock‐down, and rescued the cells from death caused by Aβ1–42 peptide. Taken together, these results suggest that F‐spondin may play a critical role in murine neuroblastoma survival under adverse conditions by maintaining IL‐6 level via a MEKK/p38 MAPK/NF‐κB‐dependent pathway.
l‐Aspartate as an amino acid neurotransmitter: mechanisms of the depolarization‐induced release from cerebrocortical synaptosomes
Authors: Cavallero Anna , Marte Antonella , Fedele Ernesto 
Published: June 2009

AbstractThe role ofl‐aspartate as a classical neurotransmitter of the CNS has been a matter of great debate. In this study, we have characterized the main mechanisms of its depolarization‐induced release from rat purified cerebrocortical synaptosomes in superfusion and compared them with those of the well‐known excitatory neurotransmitterl‐glutamate. High KCl and 4‐aminopyridine were used as depolarizing agents. At 15 mM KCl, the overflows of both transmitters were almost completely dependent on external Ca2+. At 35 and 50 mM KCl, the overflows ofl‐aspartate, but not those ofl‐glutamate, became sensitive todl‐threo‐β‐benzyloxyaspartic acid (dl‐TBOA), an excitatory amino acid transporter inhibitor. In the presence ofdl‐TBOA, the 50 mM KCl‐evoked release ofl‐aspartate was still largely external Ca2+‐dependent. Thedl‐TBOA insensitive, external Ca2+‐independent component of the 50 mM KCl‐evoked overflows ofl‐aspartate andl‐glutamate was significantly decreased by the mitochondrial Na+/Ca2+exchanger blocker CGP 37157. The Ca2+‐dependent, KCl‐evoked overflows ofl‐aspartate andl‐glutamate were diminished by botulinum neurotoxin C, although to a significantly different extent. The 4‐aminopyridine‐inducedl‐aspartate andl‐glutamate release was completely external Ca2+‐dependent and never affected bydl‐TBOA. Superimposable results have been obtained by pre‐labeling synaptosomes with [3H]d‐aspartate and [3H]l‐glutamate. Therefore, our data showing thatl‐aspartate is released from nerve terminals by calcium‐dependent, exocytotic mechanisms support the neurotransmitter role of this amino acid.
A highly conserved tryptophan residue in the fourth transmembrane domain of the A1 adenosine receptor is essential for ligand binding but not receptor homodimerization
Authors: Suzuki Tokiko , Namba Kazunori , Yamagishi Ryosuke , Kaneko Hiroki , Haga Tatsuya , Nakata Hiroyasu 
Published: June 2009

AbstractDimerization between G protein‐coupled receptors (GPCRs) is a clearly established phenomenon. However, limited information is currently available on the interface essential for this process. Based on structural comparisons and sequence homology between rhodopsin and A1 adenosine receptor (A1R), we initially hypothesized that four residues in transmembrane (TM) 4 and TM5 are involved in A1R homodimerization. Accordingly, these residues were substituted with Ala by site‐directed mutagenesis. Interestingly, the mutant protein displayed no significant decrease in homodimer formation compared with wild‐type A1R, as evident from coimmunoprecipitation and BRET2 analyses (improved bioluminescence resonance energy transfer system offered by Perkin‐Elmer Life Sciences), but lost ligand binding activity almost completely. Further studies disclosed that this effect was derived from the mutation of one particular residue, Trp132, which is highly conserved among many GPCRs. Confocal immunofluorescence and cell‐surface biotinylation studies revealed that the mutant receptors localized normally at transfected cell membranes, signifying that loss of ligand binding was not because of defective cellular trafficking. Molecular modeling of the A1R‐ligand complex disclosed that Trp132 interacted with several residues located in TM3 and TM5 that stabilized agonist binding. Thus, loss of interactions of Trp with these residues may, in turn, disrupt binding to agonists. Our study provides strong evidence of the essential role of the highly conserved Trp132 in TM4 of adenosine receptors.
The SIRT1 activator resveratrol protects SK‐N‐BE cells from oxidative stress and against toxicity caused by α‐synuclein or amyloid‐β (1‐42) peptide
Authors: Albani Diego , Polito Letizia , Batelli Sara , De Mauro Stefania , Fracasso Claudia , Martelli Giuliana , Colombo Laura , Manzoni Claudia , Salmona Mario , Caccia Silvio , Negro Alessandro , Forloni Gianluigi 
Published: June 2009

AbstractHuman sirtuins are a family of seven conserved proteins (SIRT1‐7). The most investigated is the silent mating type information regulation‐2 homolog (SIRT1, NM_012238), which was associated with neuroprotection in models of polyglutamine toxicity or Alzheimer’s disease (AD) and whose activation by the phytocompound resveratrol (RES) has been described. We have examined the neuroprotective role of RES in a cellular model of oxidative stress, a common feature of neurodegeneration. RES prevented toxicity triggered by hydrogen peroxide or 6‐hydroxydopamine (6‐OHDA). This action was likely mediated by SIRT1 activation, as the protection was lost in the presence of the SIRT1 inhibitor sirtinol and when SIRT1 expression was down‐regulated by siRNA approach. RES was also able to protect SK‐N‐BE from the toxicity arising from two aggregation‐prone proteins, the AD‐involved amyloid‐β (1‐42) peptide (Aβ42) and the familiar Parkinson’s disease linked α‐synuclein(A30P) [α‐syn(A30P)]. Alpha‐syn(A30P) toxicity was restored by sirtinol addition, while a partial RES protective effect against Aβ42 was found even in presence of sirtinol, thus suggesting a direct RES effect on Aβ42 fibrils. We conclude that SIRT1 activation by RES can prevent in our neuroblastoma model the deleterious effects triggered by oxidative stress or α‐syn(A30P) aggregation, while RES displayed a SIRT1‐independent protective action against Aβ42.
Subcellular compartment‐specific molecular diversity of pre‐ and post‐synaptic GABAB‐activated GIRK channels in Purkinje cells
Authors: Fernández‐Alacid Laura , Aguado Carolina , Ciruela Francisco , Martín Ricardo , Colón José , Cabañero María José , Gassmann Martin , Watanabe Masahiko , Shigemoto Ryuichi , Wickman Kevin , Bettler Bernhard , Sánchez‐Prieto José , Luján Rafael 
Published: June 2009

AbstractActivation of G protein‐gated inwardly‐rectifying K+ (GIRK or Kir3) channels by metabotropic gamma‐aminobutyric acid (B) (GABAB) receptors is an essential signalling pathway controlling neuronal excitability and synaptic transmission in the brain. To investigate the relationship between GIRK channel subunits and GABAB receptors in cerebellar Purkinje cells at post‐ and pre‐synaptic sites, we used biochemical, functional and immunohistochemical techniques. Co‐immunoprecipitation analysis demonstrated that GIRK subunits are co‐assembled with GABAB receptors in the cerebellum. Immunoelectron microscopy showed that the subunit composition of GIRK channels in Purkinje cell spines is compartment‐dependent. Thus, at extrasynaptic sites GIRK channels are formed by GIRK1/GIRK2/GIRK3, post‐synaptic densities contain GIRK2/GIRK3 and dendritic shafts contain GIRK1/GIRK3. The post‐synaptic association of GIRK subunits with GABAB receptors in Purkinje cells is supported by the subcellular regulation of the ion channel and the receptor in mutant mice. At pre‐synaptic sites, GIRK channels localized to parallel fibre terminals are formed by GIRK1/GIRK2/GIRK3 and co‐localize with GABAB receptors. Consistent with this morphological evidence we demonstrate their functional interaction at axon terminals in the cerebellum by showing that GIRK channels play a role in the inhibition of glutamate release by GABAB receptors. The association of GIRK channels and GABAB receptors with excitatory synapses at both post‐ and pre‐synaptic sites indicates their intimate involvement in the modulation of glutamatergic neurotransmission in the cerebellum.
Oxidized phosphatidylcholine formation and action in oligodendrocytes
Authors: Qin Jingdong , Testai Fernando D , Dawson Sylvia , Kilkus John , Dawson Glyn 
Published: June 2009

AbstractReactive oxygen species play a major role in neurodegeneration. Increasing concentrations of peroxide induce neural cell death through activation of pro‐apoptotic pathways. We now report that hydrogen peroxide generated sn‐2 oxidized phosphatidylcholine (OxPC) in neonatal rat oligodendrocytes and that synthetic OxPC [1‐palmitoyl‐2‐(5′‐oxo)valeryl‐sn‐glycero‐3 phosphorylcholine, POVPC] also induced apoptosis in neonatal rat oligodendrocytes. POVPC activated caspases 3 and 8, and neutral sphingomyelinase (NSMase) but not acid sphingomyelinase. Downstream pro‐apoptotic pathways activated by POVPC treatment included the Jun N‐terminal kinase proapoptotic cascade and the degradation of phospho‐Akt. Activation of NSMase occurred within 1 h, was blocked by inhibitors of caspase 8, increased mainly C18 and C24:1 ceramides, and appeared to be concentrated in detergent‐resistant microdomains (Rafts). We concluded that OxPC initially activated NSMase and converted sphingomyelin into ceramide to mediate a series of downstream pro‐apoptotic events in oligodendrocytes.
Stress hormones collaborate to induce lymphocyte apoptosis after high level spinal cord injury
Authors: Lucin Kurt M. , Sanders Virginia M. , Popovich Phillip G. 
Published: June 2009

AbstractPost‐traumatic immune suppression renders individuals with spinal cord injury (SCI) susceptible to infection. Normally, proper immune function is regulated by collaboration between the sympathetic nervous system (SNS) and hypothalamic–pituitary–adrenal (HPA) axis and involves the controlled release of glucocorticoids (GCs) and norepinephrine (NE). Recently, we showed that after high thoracic (T3) SCI, aberrant levels of GCs and NE accumulate in the blood and spleen, respectively. These changes are associated with splenic atrophy, splenic leucopenia, increased intrasplenic caspase 3 levels, and suppressed B lymphocyte function. As GCs boost SNS function, in part by increasing the expression and affinity of β2 adrenergic receptors (β2ARs) while simultaneously preventing β2AR down‐regulation, we predicted that surges in stress hormones (i.e., GCs and NE) in the blood and spleen of mice with high‐level SCI would act concurrently to adversely affect lymphocyte function and survival. Here, we show that post‐SCI concentrations of GCs enhance the sensitivity of lymphocytes to β2AR stimulation causing an increase in intracellular Bcl‐2 interacting mediator of cell death (Bim) and subsequent apoptosis.In vivo, the combined antagonism of GC receptors and β2ARs significantly diminished lymphocyte Bim levels and SCI‐induced splenic lymphopenia. Together, these data suggest that pharmacological antagonists of the HPA/SNS axes should be considered as adjunct therapies for ameliorating post‐traumatic immune suppression in quadriplegics and high paraplegics.
Morphine withdrawal regulates phosphorylation of cAMP response element binding protein (CREB) through PKC in the nucleus tractus solitarius‐A2catecholaminergic neurons
Authors: Martín Fátima , Laorden M. Luisa , Milanés M. Victoria 
Published: June 2009

AbstractThe transcription factor cAMP response element binding protein (CREB) has been implicated in the actions of drugs of abuse in several brain areas. However, little is known about CREB regulation in the nucleus tractus solitarius (NTS)‐A2catecholaminergic cell group, one of the key regions of the brain stress system. Morphine withdrawal modulates gene expression in the NTS through various second‐messenger signal transduction systems including activation of extracellular signal‐regulated kinases 1/2 (ERK1/2) and protein kinase C (PKC). In the current study we used immunoblotting and immunohistochemistry to investigate changes in CREB phosphorylation in the NTS and kinases that may mediate the morphine withdrawal‐triggered activation of CREB and hypothalamo‐pituitary‐adrenocortical (HPA) axis (another stress system circuit) response after naloxone‐induced morphine withdrawal. We found an increased phosphorylation of CREB (pCREB) selectively within tyrosine hydroxylase (TH) immunoreactive neurons in the NTS from morphine‐withdrawn rats, which parallel elevated corticosterone levels. We also measured expression levels of TH and phosphorylated ERK1/2(pERK1/2), and found that both are up‐regulated following morphine withdrawal. SL327, an inhibitor of ERK activation, at doses which reduced the hyperactive pERK1/2levels, did not attenuated the rise in pCREB and TH immunoreactivity or plasma corticosterone secretion during morphine withdrawal, indicating that ERK kinase/ERK pathway was not directly needed for either activation of CREB and TH expression in the NTS or HPA axis hyperactivity. In contrast, PKC inhibitor calphostin C reduced the withdrawal‐triggered rise in pCREB, pERK1/2, TH expression and corticosterone secretion. The results indicate that PKC mediates both CREB activation and HPA response by morphine withdrawal and might suggest that CREB activation in the NTS is related to TH expression associated with morphine withdrawal.
Leucine‐rich repeat kinase 2 phosphorylates brain tubulin‐beta isoforms and modulates microtubule stability – a point of convergence in Parkinsonian neurodegeneration?
Authors: Gillardon Frank 
Published: June 2009

AbstractAutosomal dominant mutations in leucine‐rich repeat kinase 2 (LRRK2) are the most common genetic cause of late‐onset Parkinson’s disease. The most prevalent LRRK2(G2019S) mutation has repeatedly been shown to enhance kinase activity and neurotoxicity, however, the molecular mechanisms leading to neurodegeneration remain poorly defined. Here we show that recombinant human LRRK2 preferentially phosphorylates tubulin‐beta purified from bovine brain and that phosphorylation is three‐fold enhanced by the LRRK2(G2019S) mutation. By tandem mass spectrometry, Thr107 was identified as phosphorylation site which is highly conserved between tubulin‐beta family members and also between tubulin‐beta genes of different species. LRRK2 was co‐immunoprecipitated with tubulin‐beta both from wild‐type mouse brain and from LRRK2 over‐expressing, non‐neuronal human embryonic kidney 293 cells. However, an effect of LRRK2 on tubulin phosphorylation and assembly was only detectable in mouse brain samples. In vitro co‐incubation of bovine brain tubulins with LRRK2 increased microtubule stability in the presence of microtubule‐associated proteins which may explain the reduction in neurite length in LRRK2‐deficient neurons in culture. These findings suggest that LRRK2(G2019S)‐induced neurodegeneration in Parkinsonian brains may be partly mediated by increased phosphorylation of tubulin‐beta and constraining of microtubule dynamics.
Activation of the histaminergic H3receptor induces phosphorylation of the Akt/GSK‐3β pathway in cultured cortical neurons and protects against neurotoxic insults
Authors: Mariottini Chiara , Scartabelli Tania , Bongers Gerold , Arrigucci Silvia , Nosi Daniele , Leurs Rob , Chiarugi Alberto , Blandina Patrizio , Pellegrini‐Giampietro Domenico E. , Beatrice Passani Maria 
Published: June 2009

AbstractStimulation of histamine H3receptors (H3R) activates Gi/o‐proteins that inhibit adenylyl cyclase and triggers MAPK and phospholipase A2. In a previous study, we showed that H3R‐mediated phosphorylation of Akt at Ser473 occurs in primary cultures of rat cortical neurons, but neither the downstream targets nor the function of such activation were explored. In this report we address these questions. Western blotting experiments showed that H3R‐mediated activation of Akt in cultured rat cortical neurons was inhibited by LY 294004 and U0126, suggesting that it depends on phosphoinositide‐3‐kinase and mitogen‐activated protein kinase kinase. H3R activation phosphorylated, hence inactivated, the Akt downstream effector glycogen synthase kinase‐3β, increased the expression of the antiapoptotic protein Bcl‐2 and protected cultured rat and mouse cortical neurons from neurotoxic insults in a dose‐dependent manner. All these effects were inhibited by the H3R antagonist inverse/agonist thioperamide. Mouse cortical cells expressed H3R as revealed by immunostaining experiments, and stimulation of H3R phoshorylated Akt and decreased caspase 3 activity. Hence, we uncovered a yet unexplored action of the H3R that may help understand the impact of H3R signaling in the CNS.
Functional dissection of the α‐synuclein promoter: transcriptional regulation by ZSCAN21 and ZNF219
Authors: Clough Richard Lee , Dermentzaki Georgia , Stefanis Leonidas 
Published: June 2009

AbstractAlpha‐Synuclein (SNCA) is an abundant neuronal protein involved in synaptic neurotransmission. SNCA expression levels have been strongly implicated in Parkinson’s disease pathogenesis. We have previously demonstrated that in the PC12 cell line elements in intron 1 may mediate SNCA transcriptional regulation in response to neurotrophins. We have now identified transcription factor (TF) binding sites in intron 1 and the 5′‐promoter of SNCA. A binding site for the TF zinc finger and SCAN domain containing (ZSCAN)21 in the 5′‐region of intron 1 is required for intron 1 transcriptional activity. Small interfering RNA against ZSCAN21 inhibits activation in the luciferase assay and diminishes SNCA protein levels in naïve and neurotrophin‐treated PC12 cells and in primary cultured cortical neurons, demonstrating that ZSCAN21 is a novel transcriptional regulator of SNCA in neuronal cells. The 5′‐promoter of SNCA has a complex architecture, including multiple binding sites for the TF zinc finger protein (ZNF)219, which functions as both an activator and a repressor. Targeting ZSCAN21 or other TFs controlling SNCA transcriptional activity may provide novel therapeutic avenues not only for Parkinson’s disease but also for other synucleopathies.
Transformation of vivianite by anaerobic nitrate‐reducing iron‐oxidizing bacteria
Authors: MIOT J. , BENZERARA K. , MORIN G. , BERNARD S. , BEYSSAC O. , LARQUET E. , KAPPLER A. , GUYOT F. 
Published: June 2009

AbstractIn phosphate‐rich environments, vivianite (FeII3(PO4)2, 8H2O) is an important sink for dissolved Fe(II) and is considered as a very stable mineral due to its low solubility at neutral pH. In the present study, we report the mineralogical transformation of vivianite in cultures of the nitrate‐reducing iron‐oxidizing bacterial strain BoFeN1 in the presence of dissolved Fe(II). Vivianite was first transformed into a greenish phase consisting mostly of an amorphous mixed valence Fe‐phosphate. This precipitate became progressively orange and the final product of iron oxidation consisted of an amorphous Fe(III)‐phosphate. The sub‐micrometer analysis by scanning transmission X‐ray microscopy of the iron redox state in samples collected at different stages of the culture indicated that iron was progressively oxidized at the contact of the bacteria and at a distance from the cells in extracellular minerals. Iron oxidation in the extracellular minerals was delayed by a few days compared with cell‐associated Fe‐minerals. This led to strong differences of Fe redox in between these two types of minerals and finally to local heterogeneities of redox within the sample. In the absence of dissolved Fe(II), vivianite was not significantly transformed by BoFeN1. Whereas Fe(II) oxidation at the cell contact is most probably directly catalyzed by the bacteria, vivianite transformation at a distance from the cells might result from oxidation by nitrite. In addition, processes leading to the export of Fe(III) from bacterial oxidation sites to extracellular minerals are discussed including some involving colloids observed by cryo‐transmission electron microscopy in the culture medium.
Clinical supervision: an appropriate term for physiotherapists?
Authors: Hall Toni , Cox Diane 
Published: June 2009

AbstractThe aim of this study was to investigate the experiences of physiotherapists engaged in clinical supervision. It aimed to indicate whether physiotherapists understood the purpose of clinical supervision and whether the term affected their understanding and use of the process. The study is set in a physiotherapy department in an acute District General Hospital. Sixteen potential participants were contacted, eight qualified physiotherapists consented to take part. The study adopted a qualitative approach using semi‐structured audio‐taped interviews which were transcribed prior to content analysis.A key finding was that the physiotherapists did not have a clear understanding of the purpose of clinical supervision in relation to other support available, for example annual appraisal and rotational reviews. Tensions arose for those who associated clinical supervision with line management and appraisal. Clinical supervision was most effective for physiotherapists who had selected their own supervisor, who were clear about its purpose and who were able to make the link between clinical supervision, continuing professional development and reflective practice.The study concludes that the purpose of clinical supervision in relation to other support needs to be clarified to help physiotherapists use the process more effectively and that clinical supervisors should receive support and training in this important role. Clinical supervision is used for different purposes at different stages of a career and can enhance the development of confident practitioners. The term ‘clinical supervision’ is inappropriate for physiotherapists due to its lack of clarity. ‘Peer Support and Development’ is an example of an alternative title that may better describe the purpose of the activity.