bluuebunny/crossref_metadata_2025 huggingface dataset:
Activin and BMPs regulate sensory neuronal differentiation
Authors: Hall A. K. , Dinsio K. J. , Haner N. , Cruise B. A.
Published: July 2010

Regulated expression of neuropeptide transmitters in the sensory nervous system results in the ability to feel pain and modulate inflammation. These functions are carried out by sensory neurons that express calcitonin gene‐related peptide (CGRP) and project to skin, muscle or gut target tissues. Activin and members of the bone morphogenetic protein (BMP) family have been suggested to contribute to the induction of CGRP in embryonic dorsal root ganglion neurons. Bioassays using embryonic target tissues as well as cell lines derived from these tissues clearly implicate a target derived factor in the induction of CGRP. Further, embryonic tissues that serve as sensory neuron targets express biochemically detectable amounts of BMPs and activin, as well as inhibitory molecules. These data support the hypothesis that BMPs and activin regulate sensory neuron cell phenotype development. In addition, activin also appears to induce neuropeptide expression following skin injury in the adult. Following a skin wound an increased proportion of CGRP expressing neurons are present in sensory ganglia innervating the wound region. While adult skin has low activin expression, following excisional skin wound, activin protein expression in skin adjacent to the wound increased, while BMP‐2, BMP‐4, and BMP‐6 expression decreased. These data suggest that activin and BMPs are important regulators of CGRP in development and disease.
Role of bone morphogenetic protein signalling in noradrenergic neuron development
Authors: Rohrer H. , Stanke M. , Schneider C. , Muller F. , Howard M. , Vogel‐Hopker A.
Published: July 2010

The autonomic nervous system serves as an excellent model system in which one can study the emergence of distict neuronal subtypes, noradrenergic and cholinergic neurons, from the pool of pluripotent neural crest stem cells.

We have shown that signalling molecules of the family of bone morphogenetic proteins (BMPs) are essential for sympathetic neuron development. BMPs are expressed in the vicinity of developing sympathetic ganglia and control the expression of a group of transcription factors that are involved in the further specification and differentiation of sympathetic neurons. This group of transcription factors includes the bHLH proteins Mash1 and dHand and the paired homeodomain transcription factors Phox2a and Phox2b. Each of these factors is sufficient to elicit the generation of sympathetic neurons, expressing subtype‐specific and pan‐neuronal genes, to elicit the early development of sympathetic neurons. In the the central nervous system, the development of noradrenergic neurons of the locus coeruleus (LC) depends on Mash1, Phox2a and Phox2b and our recent results reveal that LC neurons are generated in response to the graded action of BMPs in the dorsal hindbrain.

Supported by grants from the Deutsche Forschungsgemeinschaft, Fonds der chemischen Industrie and the EU.
Symposium 2: The Genetic, Molecular and Cellular Bases of Neurofibromatosis Type 1. A role of NF1 as a tumor suppressor
Authors: Parada L. F. , Zhu Y.
Published: July 2010

To gain insight into the role of the NF1 (Neurofibromatosis type 1) gene during neural development and in tumorigenesis, we have utilized the bacteriophage P1, Cre/loxP system to generate a conditional allele at the NF1 locus (NF1 flox) that permits temporal and spatial ablation of function through Cre‐mediated recombination. We have been using these mice to assess the scope of NF1 requirement in distinct cell types. At the center of this approach is to identify the cells that give origin to the tumors most frequently found in NF1 patients: neurofibromas, neurofibrosarcomas, and astrocytomas. We have hypothesized that specific stem cells must lose NF1 by LOH to begin this process. I will discuss the consequences of NF1 loss in neurons, Schwann cells, and neural precursors. Distinct tumor phenotypes appear in each case. In malignant tumors, our mouse models indicate that the p53 pathway must also become mutated to cooperate with loss of NF1. Additionally, we have genetic evidence that the haploin‐sufficient state is essential for tumor appearance. These data suggest that profilactic therapies preceding tumor appearance should be considered for NF1. Acknowledgements: Funded by NINDS, NNFF, and DOD.
CNS glial progenitors and schwann cells in neurofibromatosis Type 1
Authors: Ratner N. , Miller S. J. , Ling B. , Huang Y. N. , Bennett M. R. , Mckinnon R. , Rizvi T. A.
Published: July 2010

Neurofibromatosis type 1 (NF1) one of the most common of all autosomal dominant disorders, affecting about 1 in 3500 individuals. NF1 is considered to be a tumor suppressor disease, in which lack of the NF1 gene product causes disease. NF1 predisposes patients to central nervous system dysfunction including learning disabilities and brain tumors, to bright spots on MRI scans, postulated to be nests of dysmyelination, and to peripheral nerve tumors, both benign and malignant. Glial abnormalities might account for some or all of these defects. To test this, we prepared cultures from spinal cords of embryonic day 12.5 mouse embryos with NF1 mutations. The data show that glial progenitors, both O2A cells and glial restricted progenitors (GRPs) are dramatically amplified in cultures from mutant mice spinal cords, as compared to cultures from wild type littermates. Cells with a single mutant allele show an intermediate phenotype; signalling pathway defects including elevated Ras‐GTP appear to cause the increased cell number. Schwann cells cultured from NF1 mutant E12.5 dorsal root ganglia are also highly abnormal. Mutant Schwann cells differentially express the epidermal growth factor receptor protein (EGFR). EGFR was tested for ability to drive tumor formation in transgenic mice‐ CNPase‐EGFR mice show nerve thickening, consistent with early tumor formation. The data are consistent with a key role for glial cells in brain and peripheral nerve dysfunction in NF1.

Acknowledgements:  Supported by NIH‐NS28840, the DOD Program on Neurofibromatosis, and the NMSS.
RAS activation is both necessary and sufficient to promote perineurial glial growth in Drosophila peripheral nerves
Authors: Stern M. , Fazio G. , Lynn A. , Yager J.
Published: July 2010

Drosophila peripheral nerves contain motor and sensory axons surrounded by two layers of glia: an inner peripheral glia and an outer perineurial glia. Although it is known that intercellular signalling occurs among cells of the peripheral nerve, the effects of this signalling on nerve structure is incompletely understood. It was previously shown that growth of the perineurial glia is negatively regulated by five genes: ine, which encodes a putative neurotransmitter transporter, eag, which encodes a potassium channel, push, which encodes a large, Zn2+ finger‐containing protein, amn, which encodes a putative neuropeptide with similarity to pituitary adenylate cyclase activator peptide (PACAP), and NF1, the Drosophila orthologue of human NF1. Single or various double mutants in any of these genes exhibit perineurial glial hypertrophy. We found that the Ras12A/Rase2f heteroallelic combination, which decreases Ras activity, rescues the thick perineurial glia phenotype exhibited in ine; NF1 double mutants. This result demonstrates that Ras activity is required for the effect of NF1 mutations on perineurial glial growth. We also expressed a constitutively active Ras transgene in an ine– background specifically in peripheral glia using a Gal4‐UAS system. These larvae exhibited perineurial glia thickness comparable to that of ine; NF1 double mutants. Thus, expression of constitutively active Ras in peripheral glia mimics the effect of NF1 mutations on perineurial glial growth. These results demonstrate that Ras activity is both necessary and sufficient to activate perineurial glial growth in peripheral nerves and that Ras activity controls perineurial glial growth in a cell nonautonomous manner.
Interaction between parkin and alpha‐synuclein
Authors: Shimura H. , Schlossmacher M. , Hattori N. , Mizuno Y. , Kosik K. , Selkoe D.
Published: July 2010

Mutations in the parkin gene have been identified in autosomal recessive Parkinson's disease (ARPD) throughout the world. Several groups have shown that parkin acts as an ubiquitin (Ub) ligase in in vivo and in vitro studies and identified several molecules to be ubiquitinated by parkin. Two rare mutations, Ala53Thr and Ala30Pro, in the α‐synuclein (αS) gene have been identified in autosomal dominant PD cases. αS is a major constituent of Lewy bodies the pathological hallmark of PD. Therefore, αvS metabolism is likely to play a central role in the pathogenesis of PD. We investigated the possible interaction between the two familial PD‐linked gene products, parkin and αS. We first demonstrated that parkin epitopes can be found within Lewy bodies by immunohistochemistry and immuno‐EM. We also detected parkin biochemically in affinity purified Lewy bodies. Furthermore, we identified a protein complex in normal human brain that includes parkin as an E3 Ub ligase, UbcH7 as its associated E2 protein and a novel 22 kDa glycosylated isoform of αS (αSp22) as its substrate. In an in vitro ubiquitination assay, αSp22 was further modified by normal but not mutant parkin into high Mr polyubiquitinated species. We observed accumulation of nonubiquitinated αSp22 in ARPD brain homogenates. Importantly enzymatic digestion of αSp22 abolish the binding of recombinant parkin with deglycosylated αS. We conclude that αSp22 is a substrate for parkin's Ub ligase activity in normal brain, and that loss of function in parkin‐deficient ARPD causes pathological αSp22 accumulation. These findings demonstrate a critical functional relationship between the two PD‐linked gene products.
Poster Sessions AP05: Neuronal and Glial Cell Biology. Novel roles for acetylcholinesterase in brain tumors
Authors: Kaur H. , Bigbee J. W.
Published: July 2010

Acetylcholinesterase (AChE) is classically known for terminating cholinergic transmission, however, increasing evidence shows that the biological function of AChE is not limited to this role. Interestingly, the AChE gene is either amplified, mutated and/or aberrantly expressed by cells in a variety of human tumors despite the fact that AChE is not present in their normal counterparts. Studies from our laboratory and others have shown that AChE is transiently expressed during normal neural development when cells are invariably engaged in intense growth and movement. Together, these observations support the idea that AChE may play a role in tumorigenesis, however, this hypothesis has not been tested before. In support of this idea, we have found that neuroblastoma cells genetically engineered to over‐express AChE developed tumors in vivo at a notably greater rate compared with transfection controls. Tumor cells were implanted into the brains of irradiated Fischer rats and following a 10‐day survival period, macroscopic examination revealed that the tumor mass generated from the AChE over‐expressing cells was six‐fold greater than transfection controls. Moreover, histochemical and Western blot analyses of two human glioma cell lines revealed that the different levels of AChE expression in these cells directly correlated with their proliferation rates. These studies showed that the high AChE‐expressing cells divided at a 50% greater rate than the low AChE‐expressing cells. Interestingly, the high AChE‐expressing cells also exhibited increased MAPK phosphorylation, a key step in the regulation of cell growth. These findings together with the consistent observation that AChE is misexpressed in human tumors, and the fact that AChE levels are up‐regulated during normal development, support the idea that AChE plays a role in tumor cell growth.
Alignment, zippering and splaying of microtubules during axogenesis
Authors: Baas P. W. , Yu W. , Ling C.
Published: July 2010

Microtubules are reconfigured from a scattered array to a paraxial bundle during axogenesis. One popular model posits that this reconfiguration results from the assembly dynamics of the microtubules together with structural proteins that stabilize and crosslink them. Here we show that the microtubules undergo behaviors that are not consistent with a model based on these principles alone. When cultured on polylysine, rat sympathetic neurons extend modest lamellae which contain a mass of nonaligned microtubules. Application of a mixture of growth factors called matrigel results in a rapid expansion of the lamellae followed by the outgrowth of axons. Fluorescence‐imaging of living neurons reveals sluggish movements of microtubules in neurons not exposed to matrigel. After addition of matrigel, the movements become rapid and result in dramatic changes in the microtubule array. Microtubules now extend to the periphery of the lamellae where they invade newly forming axons. The microtubules align with one another and relative to the cell cortex, and draw together into bundles. Microtubules within a bundle move apart as well, particularly in the growth cones that form at the tips of developing axons. These microtubule behaviors, which we refer to as alignment, zippering and splaying, are reminiscent of those observed in vitro when microtubules are subjected to forces generated by molecular motor proteins. High‐resolution images obtained with electron microscopy support this view, and also suggest that microtubule reconfiguration occurs in conjunction with alterations in actin, which may be a substrate for microtubule movements. We conclude that the reconfiguration of microtubules underlying axogenesis involves complex microtubule behaviors, many of which are consistent with movements generated by motor‐driven forces.
Symposium 8: Regulation of Oligodendrocyte Development. Guidance of oligodendrocyte precursor migration in the developing spinal cord
Authors: Miller R. H. , Wang R‐Z. , Tsai H‐H.
Published: July 2010

Oligodendrocyte precursors arise in restricted regions of the developing neuroepithelium due to local signals that include sonic hedgehog. In the spinal cord the founder cells of the oligodendrocyte lineage develop in a specific domain of the ventral ventricular zone. These cells or their progeny subsequently migrate long distances to populate the entire spinal cord and myelinate axons in the peripheral presumptive white matter. The majority of migration in the oligodendrocyte lineage is accomplished by immature precursors, which then stop, proliferate and differentiate in the appropriate location. Several distinct mechanisms appear to regulate this migration. The initial dispersal of cells from the ventral ventricular zone is guided by chemorepellent cues including netrin‐1 present in the ventral ventricular domain. Migratory precursors are arrested in particular locations within the developing spinal cord as the result of the localized expression of the chemokine, CXCL1 by astrocytes. This chemokine, signalling through the CXCR2 receptor combines with PDGF to inhibit cell migration and enhance cell proliferation thereby facilitating the local expansion of the oligodendrocyte lineage and myelination of all relevant axons.
Regulation of development of oligodendrocytes
Authors: Ikenaka K.
Published: July 2010

Oligodendrocyte (OL) is the myelin‐forming glial cell in the central nervous system. In the spinal cord, molecular markers for OL precursor cells (OPCs), such as PDGF a‐receptor (PDGFR a), are first expressed in a strictly restricted focus of the ventral ventricular lumen at E12.5 in mouse and later spread throughout the cord. To investigate how they originate from these specific regions, we used an explant culture system of E12 mouse cervical spinal cord. When we cultured the ventral and dorsal spinal cords separately, a robust increase in the number of O4+ cells was observed in the ventral fragment. This phenomenon suggests the presence of factors inhibiting OL development from dorsal spinal cord. BMP4 is secreted from dorsal spinal cord and is a strong candidate for this factor; however, it did not affect OL development in our system. Here we show that Wnt‐1 and Wnt‐3a, in contrast, may have a role in OL maturation. The developmental profile of wnt‐1/3a gene expressions in the dorsal spinal cord showed a significant correlation with that of the dorsal activity, which was very strong at E11, and then reduced to an undetectable level by E14. When Wnt‐3a was added to the dissociation culture prepared from E14 mouse ventral cervical cords, the numbers of OL decreased. b‐Catenin and LEF family proteins are known to form a transcription factor complex at the down stream of Wnt signalling. OL–like differentiation of CG4 cells was inhibited by constitutively active LEF‐b‐Catenin, supporting the idea that Wnt signalling directly inhibits OL differentiation.
Fibroblast growth factor receptor‐3 null mice exhibit a delay in the development of oligodendrocytes and myelination
Authors: Bansal R. , Oh L. Y. S.
Published: July 2010

Fibroblast growth factors (FGFs) comprise of a family of twenty‐three members which bind to four receptor tyrosine kinases (R1–R4). They induce a broad spectrum of biological effects in a variety of cell types, including neurons and glia in the CNS. In oligodendrocytes (OLs), FGF‐2 elicits a number of specific responses depending on their stage of development. During OL development in vitro, the expressions of FGF‐receptor mRNAs are differentially regulated. R1 mRNA increases gradually along with OL maturation, whereas R3 and R2 mRNAs peak at the OL progenitor and mature OL stages, respectively, suggesting a differential roles of these receptors in OL development. R3 is also expressed by astrocytes. To determine the roles of R3 during OL development and myelination in vivo, we have employed mice lacking functional R3 (R3‐null). During myelination (P7, P9, P13), reduced numbers of differentiated OLs and myelinated fibers are observed in the brains of R3 null mice compared to wild type mice. Moreover, up‐regulation of glial fibrillary acidic protein‐positive astrocytes is found in the cerebellum and spinal cord of R3 null mutants. However, the number of OL progenitors (PDGF‐Ra), BrdU incorporation, and cell survival (TUNEL assay) are all comparable, and R3‐null myelin in adult mice appears to be similar to that of wild type mice. In mixed primary cultures of post‐natal R3 null brain (that have few if any neurons), OLs exhibit a delay in differentiation similar to that observed in vivo. In summary, our results elucidate regulatory roles of FGF‐R3 in mouse brain, in particular with regard to its roles in the timing of OL maturation and myelin formation (MS Society, Canada, NIH NS38878‐03).
The oligodendrocyte lineage genes Olig1 and Olig2 in CNS development
Authors: Stiles C. D. , Lu Q. R. , Sun T. , Rowitch D. H.
Published: July 2010

The oligodendrocyte lineage genes Olig1 and Olig2 encode related bHLH proteins that are co‐expressed in neural progenitors. Targeted disruption of these two genes sheds light on the ontogeny of oligodendroglia and genetic requirements for their development from multipotent CNS progenitors. Olig2 is required for oligodendrocyte and motor neuron specification in the spinal cord. Olig1 has roles in development and maturation of oligodendrocytes, evident especially within the brain. Both Olig genes contribute to neural pattern formation. Neither Olig gene is required for astrocytes. These findings, together with fate mapping of Olig‐expressing cells, challenge the notion that oligodendrocytes arise from a glial‐restricted precursor. Rather, they indicate that oligodendrocytes are derived from Olig‐specified progenitors that give rise also to neurons.
Symposium 10: Differentiation Plasticity of Stem Cells. Direct differentiation of radial glial cells from embryonic stem cells
Authors: Liour S. S. , Yu R. K.
Published: July 2010

The major role of radial glial cells in neuronal development is to provide support and guidance for neuronal migration. In vitro, neurons, astrocytes and oligodendrocytes have also been generated from neural stem cells and embryonic stem cells, but the generation of radial glial cells in vitro has not yet been reported. Since radial glial cells can lead to neurons and astrocytes during brain development, neurogenesis and gliogenesis of stem cells in vitro may at least in part also utilize the same mechanisms. To test this hypothesis, we utilized five different clones of embryonic (ES) and embryonal carcinoma (EC) stem cell lines to investigate the differentiation of radial glial cells during in vitro neural differentiation. Here, we demonstrate that radial glial cells can be generated from ES/EC cell lines. These ES/EC cell‐derived radial glial cells are similar in morphology to radial glial cells in vivo. They also express several cytoskeletal markers that are characteristics of radial glial cells in vivo. The processes of these in vitro‐generated radial glial cells are organized into scaffolds that appear to support the migration of newly generated neurons in culture. Like radial glial cells in vivo, they appear to differentiate subsequently into astrocytes. Differentiation of radial glial cells may be a common pathway during in vitro neural differentiation of ES cells. This novel in vitro model system may facilitate the investigation of regulation of radial glial cell differentiation and its biological function.

Acknowledgements:  Supported by USPHS Grant NS11853 and a grant from the Children's Medical Research Foundation.
Potential of umbilical cord blood cells for brain repair
Authors: Sanberg P. R. , Chopp M. , Willing A. E. , Zigova T. , Saporta S. , Song S. , Bickford P. , Garbuzova‐Davis S. , Newman M. , Cameron D. F. , Sanchez‐Ramos J.
Published: July 2010

Our laboratory is characterizing the mononuclear cells from human umbilical cord blood (HUCB) for possible therapeutic value. Studies on HUCB cells demonstrated their ability to respond to growth factors by increased expression of neural markers and down regulation of several genes associated with development of blood lines. HUCB cells were also transplanted into the subventricular zone of the developing rat brain. It was found that some of the HUCB cells responded to external factors and were able to adopt neural fates similar to endogenous stem cells. We also tested whether intravenously infused HUCB cells enter brain, survive, differentiate and improve neurological functional recovery after stroke or traumatic brain injury (TBI) in rats. HUCB cells were injected into the tail vein at least 24 h after stroke or TBI. Behavioral impairments were significantly improved as early as 14 days in both TBI and stroke animals, compared to controls. Injected cells entered brain and migrated into the parenchyma of the injured brain. Some of these expressed neuronal, astrocytic, or endothelial markers. Our data suggest that intravenous administration of HUCB cells can provide neural stem cells, and may be a useful treatment for brain repair.

Acknowledgements:  Supported by Saneron CCEL Therapeutics, Inc. and a FL Hi‐Tech Corridor Grant.
P2 Receptors of microglia: sensors for danger signals in the CNS
Authors: Di Virgilio F.
Published: July 2010

Following tissue damage or invasion by pathogens a number of soluble signals are generated to alert the immune system of the impending danger and initiate inflammation. Some danger signals are released from injured or dying cells. Once released, danger signals activate a autocrine/paracrine network that recruits inflammatory cells, stimulates cytokine production, promotes dendritic cell maturations and increases the antigen (Ag) presenting efficiency. These events also occurs in the central nervous system (CNS) where cytokines and cytokine‐releasing cells have a central role in spreading inflammation. P2 receptors of microglia are the focus of increasing interest, especially after they were shown to mediate chemotaxis, cytokine release and cell death in microglia. We propose that P2 receptors may function in microglia as sensors of the ATP/UTP concentration in the pericellular space, and therefore as sensors of danger signals in the CNS. Furthermore, microglia itself can release ATP when stimulated by inflammatory stimuli. Thus extracellular nucleotides may be included in the family of the early inflammatory mediators acting via P2 receptors to spread inflammation in the CNS.

References  1. Ferrari D., Villalba M., Chiozzi P., Falzoni S., Ricciardi‐Castagnoli P. and Di Virgilio F. (1996) Mouse microglia cells express a plasma membrane pore gated by extracellular ATP. J. Immunol.156, 1531–1539.

2. Ferrari D., Chiozzi P., Falzoni S., Hanau S. and Di Virgilio F. (1997) Purinergic modulation of interleukin‐1B release from microglia cells stimulated with bacterial endotoxin. J. Exp. Med.185, 579–582.
Colloquium 4: The Emerging Role of Peroxisome Proliferator Activated Receptors in Brain. Role of PPARg and its natural ligand 15D‐PGJ2 in the regulation of microglia activation
Authors: Minghetti L. , Bernardo A. , Ajmone‐Cat M. A. , Levi G.
Published: July 2010

The peroxisome proliferator‐activated receptor γ (PPARγ) is a member of a large group of nuclear receptors controlling lipid and glucose metabolism, energy homeostasis, adipose cell and macrophage differentiation. We have recently shown that PPARγ is constitutively expressed in rat primary microglial cultures and is down regulated during microglial activation by endotoxin (LPS), suggesting that this receptor could play an important role in controlling microglial activation. To verify this hypothesis, we have studied the effects of the PPARγ natural ligand 15d‐PGJ2 on several functions associated with microglial activation. In microglial cultures stimulated by LPS, interferon‐γ or by their combination, 1–5 µM 15d‐PGJ2 reduced the production of nitric oxide (NO) and the expression of inducible NO synthase, the synthesis of tumour necrosis factoralfa and the expression of MHC‐II antiogens. The effects of 15d‐PGJ2 occurred through the repression of the transcription factors, STAT‐1 and NF‐kB, and were mimicked by ciglitazone, a synthetic PPARγ agonist, suggesting the involvement of PPARγ. At lower concentrations 15d‐PGJ2, but not ciglitazone, reduced the LPS‐induced PGE2 production, suggesting that PPARγ independent mechanism(s) could contribute to this inhibitory activity. Finally, at high concentration (10 µM) 15d‐PGJ2 induced a time‐dependent mitochondrial impairment which was paralleled by an increased number of apoptotic and necrotic microglial cells. Altogether, our observations strongly suggest that 15d‐PGJ2, which is synthesised by LPS‐ activated microglia, is able to regulate the brain inflammatory response through multiple mechanisms affecting the functional state and the survival of activated microglia.
PPAR‐agonists prevent experimental autoimmune encephalomyelitis
Authors: Feinstein D. L. , Brosnan C. F. , Whitacre C. C. , Landreth G. E. , Gavrilyuk V. , Heneka M. T.
Published: July 2010

The development of clinical symptoms in multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE) involves T cell activation and migration into the central nervous system, production of glial‐derived inflammatory molecules, and demyelination and axonal damage. Ligands of the peroxisome proliferator‐activated receptor (PPAR) exert anti‐inflammatory effects on glial cells, reduce proliferation and activation of T cells, and induce myelin gene expression. We demonstrate in two models of EAE that orally administered PPARg ligand pioglitazone reduced the incidence and severity of monophasic, chronic disease in C57BL/6 mice immunized with myelin oligodendrocyte glycoprotein peptide, and of relapsing disease in B10.Pl mice immunized with myelin basic protein. Pioglitazone also reduced clinical signs when provided after disease onset. Clinical symptoms were reduced by two other PPARg agonists suggesting a role for this receptor in protective effects. Suppression of clinical signs was paralleled by decreased lymphocyte infiltration, lessened demyelination, reduced chemokine and cytokine expression, and increased IkB expression in brain. Pioglitazone also reduced the antigen‐dependent interferon‐g production from EAE‐derived T cells. These results suggest that orally administered PPARg agonists could provide therapeutic benefit in neurological diseases having an inflammatory component, including multiple sclerosis.
The unfolded protein response is activated in Pelizaeus–Merzbacher disease
Authors: Gow A. , Southwood C. M. , Garbern J. , Jiang W.
Published: July 2010

Of the myriad physiological processes ongoing in all living organisms, few are more important to survival at the levels of the cell and the organism than adaptations to stress. Even primordial life forms contended with ever changing environmental conditions by rapid changes at the transcriptional and post‐transcriptional levels and since that time virtually all species have retained, and expanded, rudimentary signalling pathways that preserve life under adverse conditions. In eukaryotes, one of these pathways is known as the unfolded protein response (UPR), which connects events in the endoplasmic reticulum with transcription through a receptor kinase cascade.

Herein, we demonstrate activation of the UPR in patients with the leukodystrophy, Pelizaeus‐Merzbacher disease (PMD), and show that this pathway is activated by coding region mutations in, but not duplication of, the PLP1 gene. Moreover, we demonstrate that the CHOP gene product, currently the most reliable indicator of an activated UPR, plays a pivotal role in the pathogenesis of PMD. These data indicate that the UPR may potentially modulate the severity of disease in any cell type expressing mutant secretory pathway proteins. Thus, PMD is the first member of a novel class of disparate degenerative diseases linked by a common molecular mechanism.
How to dissect the Node of Ranvier
Authors: Rasband M. N. , Park E. W. , Zhen D. K. , Trimmer J. S.
Published: July 2010

The node of Ranvier is composed of a complex community of axonal and glial proteins responsible for the propagation of electrical signals in myelinated nerve fibers. Both voltage‐dependent sodium and potassium channels are found in high densities in discrete axonal membrane domains, but the underlying molecular mechanisms of targeting, clustering and anchoring these proteins are unknown. We have developed monoclonal and polyclonal antibodies against known components of the node of Ranvier and have used these in immunoaffinity chromatographic procedures to co purify proteins associated with these target antigens. The isolated protein fractions were then (1) separated by SDS‐PAGE and analyzed by mass‐spectrometry and (2) used to immunize mice to develop monoclonal antibodies against novel components of the node of Ranvier. Taking this approach, we have identified a set of candidate interacting proteins that may be important for clustering, targeting, and/or anchoring proteins known to be present at the node of Ranvier. Further, we have developed a library of monoclonal antibodies against novel components of the node of Ranvier, paranode, and juxtaparanode, to be used in expression cloning and mass spectrometry to identify the corresponding antigens.
The crying shame of robot nannies
Authors: Sharkey Noel , Sharkey Amanda
Published: July 2010

Childcare robots are being manufactured and developed with the long term aim of creating surrogate carers. While total childcare is not yet being promoted, there are indications that it is ‘on the cards’. We examine recent research and developments in childcare robots and speculate on progress over the coming years by extrapolating from other ongoing robotics work. Our main aim is to raise ethical questions about the part or full-time replacement of primary carers. The questions are about human rights, privacy, robot use of restraint, deception of children and accountability. But the most pressing ethical issues throughout the paper concern the consequences for the psychological and emotional wellbeing of children. We set these in the context of the child development literature on the pathology and causes of attachment disorders. We then consider the adequacy of current legislation and international ethical guidelines on the protection of children from the overuse of robot care.
Band structures of two-dimensional magnonic crystals with different shapes and arrangements of scatterers
Authors: Cao Yongjun , Yun Guohong , Liang Xixia , Bai Narsu
Published: July 2010

The spin-wave band structures of two-dimensional magnonic crystals with different shapes and arrangements of scatterers are investigated numerically. It is shown that the magnonic band gap of spin waves in magnonic crystals can be optimized by changing the shape or the arrangement of scatterers in background materials. The largest absolute gap can be achieved when the scatterer has the same symmetry as that of the coordination polygon of lattice point, such as the case of square rods in square lattices. For a given shape of scatterer, the gap width is the largest when the lattice has the largest coordination number if the scatterer does not reduce the symmetry.
Numerical model analysis of the shaded dye-sensitized solar cell module
Authors: Chen Shuanghong , Weng Jian , Huang Yang , Zhang Changneng , Hu Linhua , Kong Fantai , Wang Lijun , Dai Songyuan
Published: July 2010

On the basis of a numerical model analysis, the photovoltaic performance of a partially shadowed dye-sensitized solar cell (DSC) module is investigated. In this model, the electron continuity equation and the Butler–Vollmer equation are applied considering electron transfer via the interface of transparent conducting oxide/electrolyte in the shaded DSC. The simulation results based on this model are consistent with experimental results. The influence of shading ratio, connection types and the intensity of irradiance has been analysed according to experiments and numerical simulation. It is found that the performance of the DSC obviously declines with an increase in the shaded area due to electron recombination at the TCO/electrolyte interface and that the output power loss of the shadowed DSC modules in series is much larger than that in parallel due to the ‘breakdown’ occurring at the TCO/electrolyte interface. The impact of shadow on the DSC performance is stronger with increase in irradiation intensity.
Parallel near-field optical micro/nanopatterning on curved surfaces by transported micro-particle lens arrays
Authors: Khan Ashfaq , Wang Zengbo , Sheikh Mohammad A , Whitehead David J , Li Lin
Published: July 2010

Although laser surface nanopatterning by particle lens arrays (PLA), utilizing near-field enhancement, has been extensively utilized previously, a suitable technique for the deposition of PLA on the curved surface of a cylinder was not available. In this paper, a novel technique for nanopatterning on curved surfaces using PLA is demonstrated. In the proposed technique, a hexagonal closed pack monolayer of SiO2 spheres is first formed by self-assembly on a flat glass surface. The formed monolayer of particles is then picked up by a flexible optically transparent sticky surface and placed on the substrate to be patterned. A 532 nm wavelength Nd : YVO4 laser was used to irradiate the substrate with the laser passing through the flexible, transparent surface and the particles. Experimental investigations are made to ascertain the properties of the patterns. In addition, the optical near-field distribution around the particles is numerically simulated. The proposed technique is validated for nanopatterning of the curved surface of a cylinder.
Effect of laser beam energy density on the structural and electrical properties of TiO2-doped Bi5Nb3O15 thin film grown by pulsed laser deposition
Authors: Sun Jong-Woo , Kang Lee-Seung , Kim Jin-Seong , Paik Dong-Soo , Nahm Sahn , Seong Tae-Geun , Kang Chong-Yun , Kim Jong-Hee
Published: July 2010

With the addition of TiO2, the dielectric constant (εr) of a Bi5Nb3O15(B5N3) film was slightly increased and the leakage current decreased, probably due to the increased dipole moment and the decreased number of free electrons in the film, respectively. The energy density of the laser beam considerably influenced the structure and electrical properties of the 1.0 mol% TiO2-doped B5N3 (TBN) films. At low beam energy densities (⩽2.0 J cm−2), Bi3NbO7 and Bi8Nb18O57 phases with a porous microstructure were formed and a poor interface was also formed between the film and the electrode. However, for the TBN film grown at 200 °C at a high beam energy density of 4.0 J cm−2, a dense Bi3NbO7 phase was formed with a sharp interface. The εr value of this TBN film was very high, approximately 115, with a low leakage current density of 1.4 × 10−8 A cm−2 at 0.5 MV cm−1 and a high breakdown field of 0.55 MV cm−1. This improvement in the εr value and the electrical properties was explained by the formation of a dense Bi3NbO7 phase with a (1 1 1) preferred orientation, Ti doping and a sharp interface, indicating that the TBN film is a good candidate material for embedded capacitors.
Gluconate Metabolism Is Required for Virulence of the Soft-Rot Pathogen Pectobacterium carotovorum
Authors: Mole Beth , Habibi Sohrab , Dangl Jeffery L. , Grant Sarah R.
Published: July 2010

Pectobacterium carotovorum is a ubiquitous soft rot pathogen that uses global virulence regulators to coordinate pathogenesis in response to undefined environmental conditions. We characterize an operon in P. carotovorum required for gluconate metabolism and virulence. The operon contains four genes that are highly conserved among proteobacteria (initially annotated ygbJKLM), one of which was misassigned as a type III secreted effector, (ygbK, originally known as hopAN1). A mutant with a deletion-insertion within this operon is unable to metabolize gluconate, a precursor for the pentose phosphate pathway. The mutant exhibits attenuated growth on the leaves of its host of isolation, potato, and those of Arabidopsis thaliana. Notably, the mutant hypermacerates potato tubers and is deficient in motility. Global virulence regulators that are responsive to cell wall pectin breakdown products and other undefined environmental signals, KdgR and FlhD, respectively, are misregulated in the mutant. The alteration of virulence mediated via changes in transcription of known global virulence regulators in our ygbJ-M operon mutant suggests a role for host-derived catabolic intermediates in P. carotovorum pathogenesis. Thus, we rename this operon in P. carotovorum vguABCD for virulence and gluconate metabolism.
Interactions Between Tobamovirus Replication Proteins and Cellular Factors: Their Impacts on Virus Multiplication
Authors: Ishibashi Kazuhiro , Nishikiori Masaki , Ishikawa Masayuki
Published: July 2010

Most viral gene products function inside cells in the presence of various host proteins, nucleic acids, and lipids. Thus, viral gene products come into direct contact with these molecules. The replication proteins of tobamovirus participate not only in viral genome replication but also in counterdefense mechanisms against RNA silencing and other plant defense systems. Accumulating evidence indicates that these functions are carried out through interactions with specific host components. Interactions with some cellular factors, however, are inhibitory to virus multiplication and contribute to host range restriction of tobamovirus. The interactions that have positive and negative impacts on virus multiplication should have been maintained and lost, respectively, during adaptation of the viruses to their respective natural hosts. This review lists the host factors that interact with the replication proteins of tobamovirus and discusses how they influence multiplication of the virus.
Alterations in the Host Defense Properties of Human Milk Following Prolonged Storage or Pasteurization
Authors: Akinbi Henry , Meinzen‐Derr Jareen , Auer Christine , Ma Yan , Pullum Derek , Kusano Ryosuke , Reszka Krzysztof J , Zimmerly Kira
Published: July 2010

Objectives:

Preterm infants are often fed pasteurized donor milk or mother's milk that has been stored frozen for up to 4 weeks. Our objectives were to assess the impact of pasteurization or prolonged storage at −20°C on the immunologic components of human milk and the capability of the different forms of human milk to support bacterial proliferation.

Materials and Methods:

The concentrations and activities of major host defense proteins in the whey fractions of mother's milk stored for 4 weeks at −20°C or pasteurized human donor milk were compared with freshly expressed human milk. Proliferation of bacteria incubated in the 3 forms of human milk was assessed.

Results:

Relative to freshly expressed human milk, the concentrations of lysozyme, lactoferrin, lactoperoxidase, and secretory immunoglobulin A were reduced 50% to 82% in pasteurized donor milk and the activities of lysozyme and lactoperoxidase were 74% to 88% lower (P < 0.01). Proliferation of bacterial pathogens in pasteurized donor milk was enhanced 1.8‐ to 4.6‐fold compared with fresh or frozen human milk (P < 0.01).

Conclusions:

The immunomodulatory proteins in human milk are reduced by pasteurization and, to a lesser extent, by frozen storage, resulting in decreased antibacterial capability. Stringent procedure to minimize bacterial contamination is essential during handling of pasteurized milk.
Isolation of atypical enteropathogenic Escherichia coli from children with and without diarrhoea in Delhi and the National Capital Region, India
Authors: Ghosh Pankaj Kumar , Ali Arif
Published: July 2010

A total of 17 typical and atypical enteropathogenicEscherichia coli(EPEC) were isolated from 396 children with and without diarrhoea. Out of 12 EPEC isolates from patients with diarrhoea, 3 (25 %) were atypical EPEC while 9 (75 %) were typical EPEC. It was observed that atypical EPEC strains had colonized the intestines of healthy children and its isolation rates were higher in healthy children than in children with diarrhoea. Interestingly all of the atypical EPEC isolates carried a megaplasmid, mostly comparable with the size of EPEC adherence factor (EAF) encoding gene but no virulence gene was detected in this megaplasmid. Studies also indicated that multidrug resistance EPEC are emerging and all the atypical EPEC strains showed significantly less resistance to all antimicrobial agents used in this study than typical EPEC. This study also supports the opinion that Shiga toxin-producingE. colidoes not pose a major threat to human health in India. Subtyping analysis reveals thateae-α1,eae-β2 andeae-λcould be common EPEC subtypes prevalent in children with diarrhoea in Delhi. The present study is believed to be the first report of the detection of atypical EPEC from children without diarrhoea and records of isolation ofeae-γ1,eae-γ2 and the rareeae-λsubtype in India. The data also indicated that typical EPEC are a common cause of diarrhoea and atypical EPEC are emerging as colonizers of the intestine of children with and without diarrhoea in Delhi and the National Capital Region, India.
Mycobacterium avium complex suppurative parotitis in a patient with human immunodeficiency virus infection presenting with immune reconstitution inflammatory syndrome
Authors: Babiker Zahir Osman Eltahir , Beeston Christine , Purcell Janet , Desai Niranjan , Ustianowski Andrew
Published: July 2010

Restoration of the immune system following initiation of antiretroviral therapy can result in an adverse phenomenon known as immune reconstitution inflammatory syndrome (IRIS). Herein, we report a case of Mycobacterium avium complex (MAC) suppurative parotitis associated with IRIS in a patient with advanced human immunodeficiency virus disease. To the best of our knowledge, this is the first reported case of MAC parotitis in the setting of IRIS and clinicians should be aware of this condition.
Functional roles for the GerE-family carboxyl-terminal domains of nitrate response regulators NarL and NarP of Escherichia coli K-12
Authors: Lin Alice V. , Stewart Valley
Published: July 2010

NarL and NarP are paralogous response regulators that control anaerobic gene expression in response to the favoured electron acceptors nitrate and nitrite. Their DNA-binding carboxyl termini are in the widespread GerE–LuxR–FixJ subfamily of tetrahelical helix–turn–helix domains. Previous biochemical and crystallographic studies with NarL suggest that dimerization and DNA binding by the carboxyl-terminal domain (CTD) is inhibited by the unphosphorylated amino-terminal receiver domain. We report here that NarL-CTD and NarP-CTD, liberated from their receiver domains, activated transcriptionin vivofrom the class IInapFandyeaRoperon control regions, but failed to activate from the class InarGandfdnGoperon control regions. Alanine substitutions were made to examine requirements for residues in the NarL DNA recognition helix. Substitutions for Val-189 and Arg-192 blocked DNA binding as assayed bothin vivoandin vitro, whereas substitution for Arg-188 had a strong effect onlyin vivo. Similar results were obtained with the corresponding residues in NarP. Finally, Ala substitutions identified residues within the NarL CTD as important for transcription activation. Overall, results are congruent with those obtained for other GerE-family members, including GerE, TraR, LuxR and FixJ.
Huaier aqueous extract inhibits proliferation of breast cancer cells by inducing apoptosis
Authors: Zhang Ning , Kong Xiaoli , Yan Shi , Yuan Cunzhong , Yang Qifeng
Published: July 2010

Aqueous extract of Trametes robiniophila murr (Huaier) has been commonly used in China for cancer complementary therapy in recent years; however, the mechanisms of its anticancer effects are largely unknown. In the present study, we aim to investigate its inhibitory effect on both MCF‐7 and MDA‐MB‐231 cells, and explore the possible mechanisms of its anticancer effect. Cell viability and motility were measured by MTT and invasive assays, migration and scratch assays in vitro, respectively. The distribution of cell cycle, PI‐Annexin‐V staining and Rhodamine 123 assay were analyzed by flow cytometry, and western blot were used to test the apoptotic pathways. We found that Huaier extract could strongly inhibit cell viability of MCF‐7 and MDA‐MB‐231 cells in a time‐ and dose‐dependent manner; however, MDA‐MB‐231 cells showed more susceptibility to the treatment. Furthermore, cell invasiveness and migration were also suppressed with exposure to Huaier extract. We also indicated that Huaier could induce G0/G1 cell‐cycle arrest, p53 accumulation and activation selectively in MCF‐7 cells. Inspiringly, the PI‐Annexin‐V staining assay and western blot analysis confirmed cell apoptosis executed by caspase‐3. Decreased mitochondrial membrane potential by Rhodamine 123 assay and down‐regulation of Bcl‐2 and up‐regulation of BCL2‐associated X protein (BAX) indicated that Huaier induced apoptosis through the mitochondrial pathway. Caspase activation during Huaier‐induced apoptosis was confirmed by pan‐caspase inhibitor, Z‐VAD‐fmk. As expected, the inhibitor decreased Huaier‐induced apoptosis in both cell lines. Based on our findings, Huaier can induce cell apoptosis in both ER‐positive and ER‐negative breast cancer cell lines and is an effective complementary agent for breast cancer treatment. (Cancer Sci 2010; 101: 2375–2383)