1.
Region Specific and Worldwide Distribution of Collagen-Binding M Proteins with PARF Motifs among Human Pathogenic Streptococcal Isolates.
Source
Department of Microbial Pathogenesis, Helmholtz Centre for Infection Research, Braunschweig, Germany.
Abstract
Some of the variety of Streptococcus pyogenes and Streptococcus dysgalactiae ssp. equisimilis (SDSE) M proteins act as collagen-binding adhesins that facilitate acute infection. Moreover, their potential to trigger collagen autoimmunity has been implicated in the pathogenesis of acute rheumatic fever and attributed to a collagen-binding motif called PARF (peptide associated with rheumatic fever). For the first time we determine the rate of clinical isolates with collagen-binding M proteins that use a PARF motif (A/T/E)XYLXX(L/F)N in a defined geographic region, Vellore in South India. In this region both, incidence of streptococcal infections and prevalence of acute rheumatic fever are high. M proteins with PARF motif conferred collagen-binding activity to 3.9% of 153 S. pyogenes and 10.6% of 255 SDSE clinical isolates from Vellore. The PARF motif occurred in three S. pyogenes and 22 SDSE M protein types. In one of the S. pyogenes and five of the SDSE M proteins that contained the motif, collagen-binding was impaired, due to influences of other parts of the M protein molecule. The accumulated data on the collagen binding activity of certain M protein types allowed a reanalysis of published worldwide emm-typing data with the aim to estimate the rates of isolates that bind collagen via PARF. The results indicate that M proteins, which bind collagen via a PARF motif, are epidemiologically relevant in human infections, not only in Vellore. It is imperative to include the most relevant collagen-binding M types in vaccines. But when designing M protein based vaccines it should be considered that collagen binding motifs within the vaccine antigen remain potential risk factors.
- PMID:
- 22253902
- [PubMed - as supplied by publisher]
- PMCID: PMC3256231
Persistence of Borrelia burgdorferi in Rhesus Macaques following Antibiotic Treatment of Disseminated Infection.
Source
Divisions of Bacteriology & Parasitology, Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana, United States of America.
Abstract
The persistence of symptoms in Lyme disease patients following antibiotic therapy, and their causes, continue to be a matter of intense controversy. The studies presented here explore antibiotic efficacy using nonhuman primates. Rhesus macaques were infected with B. burgdorferi and a portion received aggressive antibiotic therapy 4-6 months later. Multiple methods were utilized for detection of residual organisms, including the feeding of lab-reared ticks on monkeys (xenodiagnosis), culture, immunofluorescence and PCR. Antibody responses to the B. burgdorferi-specific C6 diagnosticpeptide were measured longitudinally and declined in all treated animals. B. burgdorferi antigen, DNA and RNA were detected in the tissues of treated animals. Finally, small numbers of intact spirochetes were recovered by xenodiagnosis from treated monkeys. These results demonstrate that B. burgdorferi can withstand antibiotic treatment, administered post-dissemination, in a primate host. Though B. burgdorferi is not known to possess resistance mechanisms and is susceptible to the standard antibiotics (doxycycline, ceftriaxone) in vitro, it appears to become tolerant post-dissemination in the primate host. This finding raises important questions about the pathogenicity of antibiotic-tolerant persisters and whether or not they can contribute to symptoms post-treatment.
- PMID:
- 22253822
- [PubMed - in process]
- PMCID: PMC3256191
Disruption of the Murine Glp2r Impairs Paneth Cell Function and Increases Susceptibility to Small Bowel Enteritis.
Source
Department of Medicine, Mt. Sinai Hospital, Samuel Lunenfeld Research Institute (S.-J.L., J.L., K.K.L., D.H., B.Y., D.J.D.), and the Department of Cell and Systems Biology (H.M., D.S.G.), University of Toronto, Toronto Ontario, Canada M5G 1X5.
Abstract
Exogenous glucagon-like peptide-2 receptor (GLP-2R) activation elicits proliferative and cytoprotective responses in the gastrointestinal mucosa and ameliorates experimental small and large bowel gut injury. Nevertheless, the essential physiological role(s) of the endogenous GLP-2R remain poorly understood. We studied the importance of the GLP-2R for gut growth, epithelial cell lineage allocation, the response to mucosal injury, and host-bacterial interactions in Glp2r(-/-) and littermate control Glp2r(+/+) mice. Glp2r(-/-) mice exhibit normal somatic growth and preserved small and large bowel responses to IGF-I and keratinocyte growth factor. However, Glp2r(-/-) mice failed to up-regulate intestinal epithelial c-fos expression in response to acute GLP-2 administration and do not exhibit changes in small bowel conductance or small or large bowel growth after administration of GLP-2R agonists. The crypt and villus compartment and the numbers and localization of Paneth, enteroendocrine, and goblet cells were comparable in Glp2r(+/+) vs. Glp2r(-/-) mice. Although the severity and extent of colonic mucosal injury in response to 3% oral dextran sulfate was similar across Glp2r genotypes, Glp2r(-/-) mice exhibited significantly increased morbidity and mortality and increased bacterial translocation after induction of enteritis with indomethacin and enhanced mucosal injury in response to irinotecan. Moreover, bacterial colonization of the small bowel was significantly increased, expression of Paneth cell antimicrobial gene products was reduced, and mucosal bactericidal activity was impaired in Glp2r(-/-) mice. Although the Glp2r is dispensable for gut development and the response to colonic injury, Glp2r(-/-) mice exhibit enhanced sensitivity to small bowel injury, and abnormal host-bacterial interactions in the small bowel.
- PMID:
- 22253424
- [PubMed - as supplied by publisher]
Molecular Characterization and Biological Function of Neuroendocrine Regulatory Peptide-3 in the Rat.
Source
Department of Physiology (H.F., T.O., Y.U.), School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan; Department of Molecular Pharmacology (K.S., E.M.-S., N.M.), National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka 565-8565, Japan; Department of Cellular Neurophysiology (G.D.), Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, European Union Centre of Excellence, Prague 14220, Czech Republic; Institut des Sciences Biologiques, Physiologie Moléculaire et Integrative, Centre Nationale de la Recheche Scientifique, Paris 75794, France; and Innovative Drug Research Laboratories (M.Y.), Kyowa Hakko Kirin Co., Ltd., Machida, Tokyo 194-8533, Japan.
Abstract
Neuroendocrine regulatory peptide (NERP)-3, derived from the neurosecretory protein VGF (non-aconymic), is a new biologically active peptide identified through peptidomic analysis of the peptides secreted by an endocrine cell line. Using a specific antibody recognizing the C-terminal region of NERP-3, immunoreactive (ir)-NERP-3 was identified in acid extracts of rat brain and gut as a 30-residue NERP-3 with N-terminal pyroglutamylation. Assessed by radioimmunoassay, ir-NERP-3 was more abundant in the brain, including the posterior pituitary (PP), than in the gut. Immunohistochemistry demonstrated that ir-NERP-3 was significantly increased in the suprachiasmatic nucleus, the magnocellular division of the paraventricular nucleus, and the external layer of the median eminence, but not in the supraoptic nucleus, after dehydration. The immunoreactivity was, however, markedly decreased in all of these locations after chronic salt loading. Intracerebroventricular administration of NERP-3 in conscious rats induced Fos expression in a subset of arginine vasopressin (AVP)-containing neurons in the supraoptic nucleus and the magnocellular division of the paraventricular nucleus. On in vitro isolated rat PP preparations, NERP-3 caused a significant AVP release in a dose-related manner, suggesting that NERP-3 in the PP could be an autocrine activator of AVP release. Taken together, the present results suggest that NERP-3 in the hypothalamo-neurohypophyseal system may be involved in the regulation of body fluid balance.
- PMID:
- 22253422
- [PubMed - as supplied by publisher]
Hexafluoroisopropanol induces self-assembly of β-amyloid peptides into highly ordered nanostructures.
Source
Council of Scientific and Industrial Research, Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India.
Abstract
Deposition of insoluble fibrillar aggregates of β-amyloid (Aβ) peptides in the brain is a hallmark of Alzheimer's disease. Apart from forming fibrils, these peptides also exist as soluble aggregates. Fibrillar and a variety of nonfibrillar aggregates of Aβ have also been obtained in vitro. Hexafluoroisopropanol (HFIP) has been widely used to dissolve Aβ and other amyloidogenic peptides. In this study, we show that the dissolution of Aβ40, 42, and 43 in HFIP followed by drying results in highly ordered aggregates. Although α-helical conformation is observed, it is not stable for prolonged periods. Drying after prolonged incubation of Aβ40, 42, and 43 peptides in HFIP leads to structural transition from α-helical to β-conformation. The peptides form short fibrous aggregates that further assemble giving rise to highly ordered ring-like structures. Aβ16-22, a highly amyloidogenic peptide stretch from Aβ, also formed very similar rings when dissolved in HFIP and dried. HFIP could not induce α-helical conformation in Aβ16-22, and rings were obtained from freshly dissolved peptide. The rings formed by Aβ40, 42, 43, and Aβ16-22 are composed of the peptides in β-conformation and cause enhancement in thioflavin T fluorescence, suggesting that the molecular architecture of these structures is amyloid-like. Our results clearly indicate that dissolution of Aβ40, 42 and 43 and the amyloidogenic fragment Aβ16-22 in HFIP results in the formation of annular amyloid-like structures. Copyright © 2012 EuropeanPeptide Society and John Wiley & Sons, Ltd.
Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
- PMID:
- 22252985
- [PubMed - as supplied by publisher]
Running throughout middle-age improves memory function, hippocampal neurogenesis and BDNF levels in female C57Bl/6J mice.
Source
Swammerdam Institute for Life Science - Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands; Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA.
Abstract
Age-related memory loss is considered to commence at middle-age and coincides with reduced adult hippocampal neurogenesis and neurotrophin levels. Consistent physical activity at midlife may preserve brain-derived neurotrophic factor (BDNF) levels, new cell genesis and learning. In the present study, 9-month-old female C57Bl/6J mice were housed with or without a running wheel and injected with bromodeoxyuridine (BrdU) to label newborn cells. Morris water maze learning, open field activity and rotarod behavior were tested 1 and 6 months after exercise onset. Here we show that long-term running improved retention of spatial memory and modestly enhanced rotarod performance at 15 months of age. Both hippocampal neurogenesis and mature BDNF peptide levels were elevated after long-term running. Thus, regular exercise from the onset and during middle-age may maintain brain function. © 2012 Wiley Periodicals, Inc. Develop Neurobiol, 2012.
Copyright © 2012 Wiley Periodicals, Inc.
- PMID:
- 22252978
- [PubMed - as supplied by publisher]
The Microtubule-Associated Protein 1A (MAP1A) is an Early Molecular Target of Soluble Aβ-Peptide.
Source
Neurobiology Research Unit 9201, Center for Integrated Molecular Brain Imaging (CIMBI), Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
Abstract
A progressive accumulation of amyloid β-protein (Aβ) is widely recognized as a pathological hallmark of Alzheimer's disease (AD). Substantial progress has been made toward understanding the neurodegenerative cascade initiated by small soluble species of Aβ and recent evidence supports the notion that microtubule rearrangements may be proximate to neuritic degeneration and deficits in episodic declarative memory. Here, we examined primary cortical neurons for changes in markers associated with synaptic function following exposure to sublethal concentrations of non-aggregated Aβ-peptide. This data show that soluble Aβ species at a sublethal concentration induce degradation of the microtubule-associated protein 1A (MAP1A) without concurrently affecting dendritic marker MAP2 and/or the pre-synaptic marker synaptophysin. In addition, MAP1A was found to highly co-localize with the postsynaptic density-95 (PSD-95) protein, proposing that microtubule perturbations might be central for the Aβ-induced neuronal dysfunctions as PSD-95 plays a key role in synaptic plasticity. In conclusion, this study suggests that disruption of MAP1A could be a very early manifestation of Aβ-mediated synaptic dysfunction-one that presages the clinical onset of AD by years. Moreover, our data support the notion of microtubule-stabilizing agents as effective AD drugs.
- PMID:
- 22252785
- [PubMed - as supplied by publisher]
Enhanced cellular uptake and metabolic stability of lipo-oligoarginine peptides.
Source
Department of Radiology, The Methodist Hospital Research Institute, Weill Cornell Medical College, Houston, TX 77030.
Abstract
Developing efficient cellular delivery vectors is crucial for designing novel therapeutic agents to enhance their plasma membrane permeability and metabolic stability in cells. Previously, we engineered cell penetrating peptide vectors named as "lipo-oligoarginine peptides" (LOAPs) by conjugating a proper combination of fatty acid and oligoarginine that translocated into cell easily without adverse effect on cell viability. In the present study, we report a systemic evaluation of cellular uptake and metabolic stability of LOAPs in Jurkat cells by introducing different combination of D-Arg residues in the peptide backbone. The cellular uptake and intracellular fate, cell viability, and metabolic stability and proteolytic degradation patterns of various LOAPs consisted of different combination of L- and D-Arg sequences were confirmed by flow cytometry, cytotoxicity assay, and analytical RP-HPLC with MALDI-TOF mass. All investigated LOAPs penetrated the cell efficiently with low cellular toxicity. The LOAPs having D-Arg residues at their N-termini seemed to have better metabolic stability than the LOAPs having C-terminal D-Arg residues. The metabolic degradation patterns were similar among all investigated LOAPs. The major hydrolytic site was between lauroyl group and β-Ala residue. Without the lipid chain, the oligoarginine peptide was pumped out ofcells easily. The results presented in this study suggest that structurally modified LOAPs could be used as a novel CPP design toward improved therapeutic application. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96: 772-779, 2011.
Copyright © 2011 Wiley Periodicals, Inc.
- PMID:
- 22252426
- [PubMed - in process]
- PMCID: PMC3261498
- [Available on 2012/5/31]
Functional importance of GLP-1 receptor species and expression levels in cell lines.
Source
Novo Nordisk, Diabetes Research Unit, Novo Nordisk Park, 2760 Maaloev, Denmark.
Abstract
Of the mammalian species, only the GLP-1 receptors of rat and human origin have been described and characterized. Here, we report the cloning of the homologous GLP-1 receptors from mouse, rabbit, pig, cynomolgus monkey and chimp. The GLP-1 receptor is highly conserved across species, thus underlining the physiological importance of thepeptide hormone and its receptor across a wide range of mammals. We expressed the receptors by stable transfection of BHK cells, both in cell lines with high expression levels of the cloned receptors, as well as in cell lines with lower expression levels, more comparable to endogenous expression of these receptors. High expression levels of cloned GLP-1 receptors markedly increased the potency of GLP-1 and other high affinity ligands, whereas the K(d) values were not affected. For a low affinity ligand like the ago-allosteric modulator Compound 2, expression levels of the human GLP-1 receptor were important for maximal efficacy as well as potency. The two natural metabolites of GLP-1, GLP-1(9-37) and GLP-1(9-36)amide were agonists when tested on a cell line with high expression of the recombinant human GLP-1 receptor, whereas they behaved as (low potent) antagonists on a cell line that expressed the receptor endogenously, as well as cells expressing a moderate level of the recombinant human GLP-1 receptor. The amide form was a more potent agonist than the free acid from. In conclusion, receptor expression level is an important parametre for selecting cell lines with cloned GLP-1 receptors for functional characterization of physiological and pharmaceutical ligands.
Copyright © 2011 Elsevier B.V. All rights reserved.
- PMID:
- 22252224
- [PubMed - as supplied by publisher]
Identification, synthesis and characterization of a novel antimicrobial peptideHKPLP derived from Hippocampus kuda Bleeker.
Source
State Key Laboratory of Biocontrol, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, National Engineering ResearchCenter of South China Sea Marine Biotechnology, Department of Biochemistry, College of Life Sciences, Sun Yat-sen University, Guangzhou, China.
Abstract
A novel gene encoding 55 amino-acid residues has been identified from the brooding pouch cDNA library of Hippocampus kuda Bleeker. The deduced amino-acid sequence is highly homologous to several pleurocidin-like peptides from the winter flounder and comprises a signal peptide, a pro-peptide and a mature peptide. The glycine-rich mature peptide, designated HKPLP, contains 24 amino-acid residues and has been synthesized by solid-phase peptidesynthesis. The purified HKPLP exhibits antimicrobial activity against several Gram-positive and Gram-negative bacterial strains at low concentrations (MIC 1.5-7.5 μM). Thermal stability assay data show good heat stability. CD spectroscopy experiments indicate that the dominant contents are anti-parallel and parallel sheets, which may have β-sheet or β-strand motif. It is inferred that HKPLP participates in the host defense during egg fertilization and embryo development as an antimicrobial peptide in brooding pouch.The Journal of Antibiotics advance online publication, 18 January 2012; doi:10.1038/ja.2011.120.
- PMID:
- 22252202
- [PubMed - as supplied by publisher]
Selective binding of CD4 and CD8 T-cells to antigen presenting cells for enrichment of CMV and HIV specific T-lymphocytes.
Source
Department of Pediatric Hematology and Oncology, Bambino Gesù Children Hospital, Rome, Italy.
Abstract
Adherent antigen presenting cells (APC) pulsed with protein or peptide antigens were used to capture specific CD4 or CD8 T-cells derived from established T-cell lines or from PBMC of immune subjects based on physiological interaction between TCR and MHC-peptide complex. This method could be applied independently of epitope specificity, HLA restriction alleles, activation markers and secreted cytokines, parameters required by other methods for selection of specific T cells. Non specific T-cells were removed by applying a 1g force that did not affect binding of specific T-lymphocytes. Lymphocyte selection was specific and the average recovery was 36% for CD4 T-cells. CD8 T-cells proved trickier to purify, since solid phase APC were recognized as targets for cytotoxicity. Specificity was comparable to CD4 cells, but the average recovery for CD8 cells was 26%. No residual alloreactivity was detected in expanded T-cells. Frequency and recovery of specific T-cells were comparable to other current technologies, such as generation of T-cell lines and cytokine capture method. Since antigen and IL2 are the only reagents added to the cultures, this physiological procedure can be proposed for selection and expansion of pathogen specific T-cells not only for research purposes, but also for adoptive reconstitution of immunocompromised subjects if performed under GMP conditions.
Copyright © 2012. Published by Elsevier B.V.
- PMID:
- 22251662
- [PubMed - as supplied by publisher]
B Lymphocytes Treated In Vitro with Antigen Coupled to Cholera Toxin B Subunit Induce Antigen-Specific Foxp3+ Regulatory T Cells and Protect against Experimental Autoimmune Encephalomyelitis.
Source
University of Gothenburg Vaccine Research Institute, Sahlgrenska Academy at the University of Gothenburg, SE-405 30, Göteborg, Sweden.
Abstract
The ability of activated B cells to protect against various experimental autoimmune or allergic diseases makes them attractive for use in cell-based therapies. We describe an efficient way to generate B cells with strong suppressive functions by incubating naive B cells with a relevant Ag conjugated to cholera toxin B subunit (CTB). This allows most B cells, irrespective of BCR, to take up and present Ag and induces their expression of latency-associated polypeptide (LAP)/TGF-β and after adoptive transfer also their production of IL-10. With OVA as model Ag, when naive T cells were cocultured in vitro with B cells pretreated with OVA conjugated to CTB (OVA/CTB) Ag-specific CD4(+) Foxp3 regulatory T (Treg) cells increased >50-fold. These cells effectively suppressed CD25(-)CD4(+) effector T (Teff) cells in secondary cultures. Adoptive transfer of OVA/CTB-treated B cells to mice subsequently immunized with OVA in CFA induced increase in Foxp3 Treg cells together with suppression and depletion of Teff cells. Likewise, adoptive transfer of B cells pulsed with myelin oligodendrocyte glycoprotein peptide(35-55) (MOGp) conjugated to CTB increased the number of Treg cells, suppressed MOGp-specific T cell proliferation and IL-17 and IFN-γ production, and prevented the development of experimental autoimmune encephalomyelitis. Similar effects were seen when B cells were given "therapeutically" to mice with early-stage experimental autoimmune encephalomyelitis. Our results suggest that B cells pulsed in vitro with relevant Ag/CTB conjugates may be used in cell therapy to induce Ag-specific suppression of autoimmune disease.
The role of ghrelin in the control of energy balance.
Source
Department of Internal Medicine and Endocrinology, Metabolic Diseases Institute, Obesity Research Center, University of Cincinnati, 2180 E. Galbraith Rd, Cincinnati, OH, 54237, USA.
Abstract
Ghrelin is the only potent orexigenic peptide in circulation. It stimulates food intake and leads to positive energy balance, adipogenesis, and body weight gain. However, the physiological significance of ghrelin in the regulation of energy homeostasis is controversial, since loss of ghrelin function in rodents does not necessarily lead to anorexia and weight loss. In this chapter, we discuss the metabolic function of ghrelin and are highlighting recent findings including the discovery and function of ghrelin-acylating enzyme ghrelin O-acyltransferase (GOAT). Based on available published data, we conclude that ghrelin is a principally important endogenous regulator of energy balance, which however may affect both food intake and systemic metabolism via independent mechanisms. Importantly, ghrelin, when acylated by GOAT, might represent a key molecular link between the sensing of consumed calories and the neuroendocrine control of energy homeostasis. Thus, agents antagonizing the action of ghrelin may have therapeutic potential in the therapy of obesity.
Leptin receptors.
Source
Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, Scotland, EH16 4TH, UK.
Abstract
The hormone leptin, secreted predominantly from adipose tissue, plays a crucial role in the regulation of numerous neuroendocrine functions, from energy homeostasis to reproduction. Genetic deficiency as a consequence of leptin or leptin receptor mutations, although rare in humans, leads to early onset of chronic hyperphagia and massive obesity. In most human obesity, however, leptin levels are chronically elevated. Under these conditions of persistent hyperleptinaemia, and particularly when obesity is associated with a high-fat diet, leptin resistance develops, and signalling through the leptin receptor is curtailed, fuelling further weight gain. Here, we review the role of leptin receptors in the regulation of feeding and obesity development. Leptin receptors are found in each of the major components of the CNS "feeding" circuitry-the brainstem, hypothalamus and distributed reward centres. Through these receptors, leptin exerts influences on signalling and integration within these circuits to alter feeding behaviours. Although some progress is now being made with peptide analogues, the leptin receptor has not proved to be amenable to small molecule pharmacological intervention to date. Where clinical benefit from recombinant leptin administration has been achieved, this has been under circumstances of complete endogenous leptin deficiency or relative hypoleptinaemia such as in lipodystrophy.
[68Ga-labeled peptides for clinical trials - Production according to the German Drug Act: The Göttingen experience.]
Source
Priv.-Doz. Dr. rer. nat. Birgit Meller, Abteilung für Nuklearmedizin, Universitätsmedizin Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Deutschland, Tel. 05 51/39 49 84, Fax 05 51/39 85 26, E-Mail: birgit.meller@medizin.uni-halle.de.
Abstract
The AMG implies far-reaching implications for the synthesis of new radiopharmaceuticals for clinical trials. Aim, methods: As a part of the DFG-funded Clinical Research Group (KFO 179) a project designated "Immuno-PET for assessment of early response to radiochemotherapy of advanced rectal cancer" was initiated. This trial is focused on a trivalent bispecific humanized monoclonal antibody, and a 68Ga-labeled peptide. Following the new regulatory framework we established a GMP-compliant cleanroom laboratory and applied for a manufacturing permission. Results: During the project constructural, personnel and organizational conditions for a successful application were established, including a quality management system. A GMP-conform cleanroom laboratory class C was constructed, equipped with a two-chamber lock. The actual manufacturing is performed in a closed system with subsequent sterile filtration. The manufacturing processes have been automatised and validated as well as the necessary quality controls. The manufacturing permission was granted after an official inspection. Conclusions: The new German Drug Act is considered as a break in the production practice of nuclear medicine. The early involvement and communication with the authorities avoids time-consuming and costly planning errors. It is much to be hoped that the new legal situation in Germany will not cause serious impairments in the realization of clinical trials in German nuclear medicine.
Further characterization of the prototypical nociceptin/orphanin FQ peptidereceptor agonist Ro 64-6198 in rodent models of conflict anxiety and despair.
Source
CNS Research, CNS Discovery, pRED, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070, Basel, Switzerland.
Abstract
RATIONALE:
Ro 64-6198, the prototypical non-peptide nociceptin/orphanin FQ peptide (NOP) receptor agonist, has potent anxiolytic-like effects in several preclinical models and species. However the effects of Ro 64-6198 on distinctive anxiety-provoking conditions related to unconditioned conflict behavior as well as its role in despair-like behavior remain to be addressed.
OBJECTIVE:
Here we examined the effects of Ro 64-6198 on unconditioned conflict anxiety using stimuli with different salience and on regulation of autonomic reactivity and compared these to the effects of benzodiazepine receptor agonists. We also addressed the potential effects of Ro 64-6198 on despair-like behavior.
MATERIALS AND METHODS:
Ro 64-6198 (0.1 to 10 mg/kg i.p.) and either diazepam or chlordiazepoxide were tested in the Vogel conflict punished drinking test (VCT) in Sprague Dawley rats, in the social approach-avoidance (SAA) test in Lewis rats, in the novelty-induced hypophagia (NIH) in C57BL/6J mice, and in stress-induced hyperthermia in NMRI mice, as well as in the forced swim test (FST) in Sprague Dawley rats and the tail suspension test (TST) in C57BL/6J mice.
RESULTS:
Ro 64-6198 (0.3 to 3 mg/kg) dose-dependently produced anxiolytic-like effects in the VCT, SAA, NIH, and SIH, similar to benzodiazepine receptor agonists. Ro 64-6198 did not alter immobility time in the FST and TST.
CONCLUSIONS:
Ro 64-6198 produced marked anxiolytic-like effects in response to a variety of mild to strong anxiogenic stimuli, whereas it did not facilitate depression-related behaviors. This data extend previous literature suggesting that NOP receptors are a viable target for the treatment of anxiety disorders.
Structural basis of high-affinity nuclear localization signal interactions with importin-α
Source
School of Chemistry and Molecular Biosciences Australian Infectious Diseases Research Centre Australian Research Council Centre of Excellence for Integrative Legume Research, The University of Queensland, Brisbane, QLD 4072, Australia School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
Abstract
Classical nuclear localization signals (cNLSs), comprising one (monopartite cNLSs) or two clusters of basic residues connected by a 10-12 residue linker (bipartite cNLSs), are recognised by the nuclear import factor importin-α. The cNLSs bind along a concave groove on importin-α, however, specificity determinants of cNLSs remain poorly understood. We present a structural and interaction analysis study of importin-α binding to both designed and naturally-occurring high-affinity cNLS-like sequences; the peptide inhibitors Bimax1 and Bimax2, and cNLS peptides of cap-binding protein 80. Our data suggest that cNLSs and cNLS-like sequences can achieve high affinity through maximising interactions at the importin-α minor site, and by taking advantage of multiple linker-region interactions. Our study defines an extended set of binding cavities on the importin-α surface, and also expands on recent observations that longer linker sequences are allowed, and that long-range electrostatic complementarity can contribute to cNLS-binding affinity. Altogether, our study explains the molecular and structural basis of the results of a number of recent studies including systematic mutagenesis and peptide library approaches, and provides an improved level of understanding on the specificity determinants of a cNLS. Our results have implications for identifying cNLSs in novel proteins.
© 2012 John Wiley & Sons A/S.
CD36 Ectodomain Phosphorylation Blocks Thrombospondin-1 Binding: Structure-Function Relationships and Regulation by Protein Kinase C.
Source
Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland OH.
Abstract
OBJECTIVE:
CD36 phosphorylation on its extracellular domain inhibits binding of thrombospondin-1. The mechanisms of cellular CD36 ectodomain phosphorylation and whether it can be regulated in cells are not known. We determined structure-function relationships of CD36 phosphorylation related to thrombospondin-1 peptide binding in vitro and explored mechanisms regulating phosphorylation by protein kinase C (PKC) in melanoma cells.
METHODS AND RESULTS:
Phosphorylation of CD36 peptide on Thr92 by PKCα suppressed binding of thrombospondin-1 peptides in vitro, and the level of inhibition correlated with the level of phosphorylation. Basal phosphorylation levels of CD36 in vivo in platelets, endothelial cells, and melanoma cells were assessed by immunoprecipitation and immunoblot and were found to be very low. Treatment of CD36-transfected melanoma cells with phorbol 12-myristate 13-acetate (PMA), a PKC activator, induced substantial CD36 phosphorylation and decreased ligand-mediated recruitment of Src-family proteins to CD36. PMA treatment did not induce detectable extracellular or cell surface-associated kinase activity, and both cycloheximide and brefeldin A blocked CD36 phosphorylation.
CONCLUSIONS:
New protein synthesis and trafficking through the Golgi are required for PMA-induced CD36 phosphorylation, suggesting that phosphorylation probably occurs intracellularly. These studies suggest a novel in vivo pathway for CD36 phosphorylation that modulates cellular affinity for thrombospondin-related proteins to blunt vascular cell signaling.
Neuroplasticity of sensory and sympathetic nerve fibers in the painful arthritic joint.
Source
Research Service, VA Medical Center, One Veterans Drive, Minneapolis, MN 55417, USA.
Abstract
OBJECTIVE.: Many forms of arthritis are accompanied by significant chronic joint pain. Here we studied whether there is significant sprouting of sensory and sympathetic nerve fibers in the painful arthritic knee joint and whether nerve growth factor (NGF) drives this pathological reorganization. METHODS.: A painful arthritic knee joint was produced by injection of complete Freund's adjuvant (CFA) into the knee joint of young adult mice. CFA-injected mice were then treated systemically with vehicle or anti-NGF antibody. Pain behaviors were assessed and at 28 days following the initial CFA injection, the knee joints were processed for immunohistochemistry using antibodies raised against calcitonin gene-related peptide (CGRP; sensory nerve fibers), neurofilament 200 kDa (NF200; sensory nerve fibers), growth associated protein-43 (GAP43; sprouted nerve fibers), tyrosine hydroxylase (TH; sympathetic nerve fibers), CD31 (endothelial cells) or CD68 (monocytes/macrophages). RESULTS.: In CFA-injected mice, but not vehicle-injected mice, there was a significant increase in the density of CD68(+) macrophages, CD31(+) blood vessels, CGRP(+) , NF200(+) , GAP43(+) , and TH(+) nerve fibers in the synovium as well as joint pain-related behaviors. Administration of anti-NGF reduced these pain-related behaviors and the ectopic sprouting of nerve fibers, but had no significant effect on the increase in density of CD31(+) blood vessels or CD68(+) macrophages. CONCLUSIONS.: Ectopic sprouting of sensory and sympathetic nerve fibers occurs in the painful arthritic joint and may be involved in the generation and maintenance of arthritic pain.
Copyright © 2012 by the American College of Rheumatology.
How the immunoassay transformed C-peptide from a duckling into a swan.
Source
Laboratory of Diabetes and Metabolic Disorders, Feinstein Institute for Medical Research, North Shore-Long Island Jewish Health System, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY, USA, jesserothmd@hotmail.com.
Abstract
This edition of 'Then and now' re-examines Lise Heding's very highly cited paper 'Radioimmunological determination of human C-peptide in serum', which was published in Diabetologia in 1975. We show how this article and other related articles by Heding contributed to heightened respect for C-peptide (and transformation of Heding's research programme). Initially thought of as an inert discard, C-peptide in blood is now recognised as an excellent surrogate measure of insulin secretion under a wide range of conditions. The assay is especially valuable for acute ascertainment of the insulin secretory capabilities of patients with type 1 diabetes or of transplanted beta cells. The assay is also being used to monitor endogenous beta cell loss or in vivo expansion of beta cell mass over the long term. We conclude with two promising future applications: (1) measurements of C-peptide in blood (along with insulin, glucose, and HbA(1c)) at annual intervals as a potential approach to earlier diagnosis of diabetes; and (2) among many recent advances in recognising properties of C-peptide (including status as a candidate hormone), most promising is C-peptide as a possible therapy for diabetic neuropathy and nephropathy.
No comments:
Post a Comment