A multicentric multimodal in vivo microscopy MRI study of bipolar disorder reveals axonal loss and demyelination

Introduction

Bipolar disorder has been repeatedly associated with abnormalities of white matter. However, DTI is intrinsically limited and the precise cellular mechanisms that underlie these alterations remains unknown.

Objectives

Our aim was to investigate microscopical characteristics of white matter using MRI in patients with bipolar and healthy controls.

Methods

77 patients and 71 controls from 3 sites had a T1 structural MRI, a multi-shell HARDI MRI and at one site with a T1-weighted VFA-SPGR acquisition, and a T2 MSME acquisition. The volume fraction and the orientation dispersion was extracted using NODDI from DW images in each site. Myelin Water Fraction was extracted in 33 patients and 36 controls to probe myelin characteristics. White matter bundles were reconstructed using deterministic tractography. Statistical analyses were performed after harmonization by the ComBat algorithm and controlled for age, gender and handedness.

Results

We found significant lower axonal density in patients along the short fibers of the left cingulum, the left anterior arcuate and the left inferior fronto-occipital fasciculus. We found lower mean MWF in patients along the short fibers of the right cingulum, the left inferior fronto-occipital fasciculus, the left anterior arcuate and the splenium of the corpus callosum. We found higher mean orientation dispersion in patients only along the left uncinate fasciculus.

Conclusions

We report alterations of limbic and inter-hemispheric white matter tracts in patients with bipolar disorder reflecting axonal loss, demyelination and architecture alterations. These results contribute to better capture the plurality of the mechanisms involved in bipolar disorder that cannot be deciphered with classical diffusion MRI.

Disclosure

No significant relationships.

Amiodarone-induced Ataxia: A Case Report of Severe Cerebellar Dysfunction and Review of Literature

Amiodarone therapy is widely prescribed in patients with atrial fibrillation. The higher prevalence of this arrhythmic heart disease, and the specific age-related issues of homeostasis in the elderly population, makes this group particularly exposed to its adverse effects. Among the many described side-effects, neurological impairments are the less documented and studied. Because amiodarone can be responsible for severe complications, as described in the case below, a close monitoring is necessary throughout its prescription. Awareness should be brought on the amiodarone-induced neurological side-effects as they could be overlooked.

Antibioticumgebruik bij de niet-gecompliceerde keizersnede bij het rund in Vlaanderen

De keizersnede is een routine-ingreep voor dierenartsen in de Vlaamse rundveepraktijk. Alhoewel de ingreep wordt aangeleerd volgens een standaardprotocol, blijkt uit eerder onderzoek dat het antibioticumgebruik bij deze indicatie sterk varieert tussen dierenartsen. In deze studie werd door middel van een vragenlijst getracht een beeld te schetsen van wanneer welke antibiotica gebruikt worden en in welke mate dit overeenstemt met de aanbevelingen van het kenniscentrum “Antimicrobial Consumption and Resistance in Animals” (AMCRA). Uit de resultaten blijkt dat alle respondenten antibiotica gebruiken tijdens de ingreep. Negentien percent dient ook standaardantibiotica toe kort na de operatie. Penicilline wordt in 52% van de gevallen als eerste keuze ingezet, wat overeenstemt met de AMCRA-richtlijnen. Het overige deel van de respondenten (48%) opteert voor breedspectrumantibiotica, zoals penicillineneomycine, penicilline-dihydrostreptomycine, lincomycine-spectinomycine, die volgens AMCRA tweedekeuzemiddelen zijn. Voor wat betreft de intramusculaire behandelingen vóór en na de ingreep, behandelt slechts 35% overeenkomstig de referentiedosering voor een koe tussen de 600 en 800 kg. Er wordt vooral ondergedoseerd bij behandelingen na de ingreep en bij nabehandeling. Op basis van de evaluatie van het tijdstip van behandelen en de antibioticumkeuze blijkt dat slechts 23% van de respondenten handelt in overeenstemming met de voorschriften van het AMCRA-formularium. Uit deze resultaten kan besloten worden dat het gebruik van antibiotica tijdens een nietgecompliceerde keizersnede sterk varieert en slechts tot op zekere hoogte overeenkomt met wat door AMCRA wordt aanbevolen. Onvoldoende kennis van de richtlijnen kan hier aan de basis liggen. Een betere communicatie is dan ook een eerste en belangrijke stap om de bewustwording te verbeteren.

Cerebellar parcellation in schizophrenia and bipolar disorder

OBJECTIVE

The cerebellum is involved in cognitive processing and emotion control. Cerebellar alterations could explain symptoms of schizophrenia spectrum disorder (SZ) and bipolar disorder (BD). In addition, literature suggests that lithium might influence cerebellar anatomy. Our aim was to study cerebellar anatomy in SZ and BD, and investigate the effect of lithium.

METHODS

Participants from 7 centers worldwide underwent a 3T MRI. We included 182 patients with SZ, 144 patients with BD, and 322 controls. We automatically segmented the cerebellum using the CERES pipeline. All outputs were visually inspected.

RESULTS

Patients with SZ showed a smaller global cerebellar gray matter volume compared to controls, with most of the changes located to the cognitive part of the cerebellum (Crus II and lobule VIIb). This decrease was present in the subgroup of patients with recent-onset SZ. We did not find any alterations in the cerebellum in patients with BD. However, patients medicated with lithium had a larger size of the anterior cerebellum, compared to patients not treated with lithium.

CONCLUSION

Our multicenter study supports a distinct pattern of cerebellar alterations in SZ and BD.

Een BVDV type 2a-besmetting op een melkveebedrijf in België

In dit artikel wordt het verloop van een boviene virale diarree virus (BVDV) type 2a-besmetting op een Belgisch melkveebedrijf beschreven. In een periode van veertien dagen stierven zeventien volwassen melkkoeien als gevolg van acuut optredende diarree en dehydratatie. Van bij het begin van de uitbraak werd aan een infectie met het BVDV gedacht, maar dit vermoeden werd niet meteen door laboratoriumtesten bevestigd. Pas tijdens de vierendertig daaropvolgende maanden kon op verschillende tijdstippen BVDV type 2a worden geïdentificeerd.

Perception, motivators and obstacles of biosecurity in cattle production

Farm biosecurity includes the prevention of disease transmission within and between farms. Two studies were set up to investigate what motivates and withholds farmers to implement biosecurity measures. The first study aimed to assess the perception of cattle farmers towards biosecurity and to identify possible reasons for its low application. This study consisted of a focus group discussion, of which the trends were used to develop a questionnaire for Flemish cattle farmers. Although the 91 participating farmers were familiar with several measures, they associated them with disease prevention rather than biosecurity. Nearly all farmers (98%) identified their herd veterinarian as their main source of information. Twenty percent and 32% of the respondents were convinced that the implementation of biosecurity would cost them more money and time, respectively. Finally, 80% of the farmers saw room for improvement of their herd, but indicated a need for practical information. The second study aimed to identify the key elements of twenty preselected biosecurity measures, motivators and obstacles for their implementation. They were judged by twenty-two cattle stakeholders, such as farmers, veterinarians and advisors, on feasibility, efficacy and return on investment. A box for parturition, a plan for rodent control and cleaning and disinfection of the stables scored highest overall. The lowest scoring measures were showering before entering the stables and an animal-free period of 24 hours. Their return on investment scored very low, since high investments are required. For a farmer to understand why biosecurity is beneficial, he must understand all risks and costs of disease and how biosecurity may reduce these risks and costs.

Biosecurity practices in Belgian cattle farming: Level of implementation, constraints and weaknesses

Over the last few years, a shift from curative towards preventive medicine occurred in the livestock sector. This led to an increased importance of biosecurity to better control infectious diseases by preventing their introduction and/or reducing their spread. Farmers are the main responsible actors of biosecurity measures (BSM). Existing studies report a low implementation level of BSM by the cattle farmers. Barriers such as cost, usefulness, importance, workload and lack of knowledge were investigated but the decision-making process of farmers related to a given BSM is not yet clarified. The objectives of this study were to (i) assess the level of implementation of BSM in cattle farms, (ii) assess the correlation between the importance that farmers give to a BSM and its effective implementation and (iii) identify the main reasons of non-implementation. A randomized survey was implemented in Belgium from December 2016 up to April 2017 with face-to-face interviews conducted in 100 Belgian farms. A descriptive analysis of data was performed using Microsoft Excel^® and Stata14^® . Chi-square and Spearman's rank correlation tests, respectively, allowed comparing implementation levels in dairy herds vs. beef herds and investigating the correlation between the importance that farmers give to a BSM and its implementation level. Biosecurity measures were poorly implemented to prevent disease introduction through direct contact and almost not to avoid indirect transmission. Some measures showed a significant difference in terms of implementation level between beef and dairy herds. A positive correlation was highlighted between the importance that farmers give to a BSM and its actual effective implementation. Perceived lack of efficiency, feasibility and usefulness are the reasons most often mentioned for non-implementation. Other factors potentially influencing the decision-making process should be further investigated and clarified. Evidence-based studies would be useful to convince the farmers of the need of implementing BSM.

Voorkomen van resistentie tegen de ‘meest kritisch belangrijke antimicrobiële geneesmiddelen’ bij Escherichia coli-isolaten van hond en kat

Om een beter inzicht te krijgen in het voorkomen van antimicrobiële resistentie tegen ‘de meest kritisch belangrijke antibiotica met hoogste prioriteit voor humane geneeskunde’ bij kleine huisdieren werd een descriptieve retrospectieve analyse van 811 antibiogrammen bij hond en kat uitgevoerd. De antibiogrammen werden door een diergeneeskundig, diagnostisch laboratorium uitgevoerd op 811 Escherichia coli-isolaten afkomstig van klinische stalen van honden en katten genomen door dierenartsen uit Vlaanderen, waarbij de isolaten voornamelijk van fecale (62,5%) of urogenitale (30,5%) oorsprong waren. De antimicrobiële gevoeligheid werd bepaald aan de hand van de disk-diffusiemethode met breekpunten voorzien door de leverancier van de antibioticumschijfjes. Met deze testmethode was 9,5% van de Escherichia coli-isolaten resistent tegen of intermediair gevoelig voor marbofloxacine, 16,7% voor enrofloxacine en 15,7% voor cefovecin. Het enigszins onverwachte verschil in resistentie tussen marbofloxacine en enrofloxacine kan mogelijk ten minste deels verklaard worden door de verschillende klinische breekpunten die gebruikt worden om de resultaten van een gevoeligheidstest voor honden- en kattenisolaten bij beide agentia te interpreteren. Het is mogelijk dat de waargenomen resistentie in deze studie het gevolg is van het regelmatige gebruik van onder andere fluoroquinolonen en derdegeneratiecefalosporinen, zodat het gebruik van deze ‘meest kritisch belangrijke antibiotica met hoogste prioriteit voor humane geneeskunde’ een belangrijk aandachtspunt in de kleinehuisdierensector blijft.

Guanidinylated Neomycin Conjugation Enhances Intranasal Enzyme Replacement in the Brain

Iduronidase (IDUA)-deficient mice accumulate glycosaminoglycans in cells and tissues and exhibit many of the same neuropathological symptoms of patients suffering from Mucopolysaccharidosis I. Intravenous enzyme-replacement therapy for Mucopolysaccharidosis I ameliorates glycosaminoglycan storage and many of the somatic aspects of the disease but fails to treat neurological symptoms due to poor transport across the blood-brain barrier. In this study, we examined the delivery of IDUA conjugated to guanidinoneomycin (GNeo), a molecular transporter. GNeo-IDUA and IDUA injected intravenously resulted in reduced hepatic glycosaminoglycan accumulation but had no effect in the brain due to fast clearance from the circulation. In contrast, intranasally administered GNeo-IDUA entered the brain rapidly. Repetitive intranasal treatment with GNeo-IDUA reduced glycosaminoglycan storage, lysosome size and number, and neurodegenerative astrogliosis in the olfactory bulb and primary somatosensory cortex, whereas IDUA was less effective. The enhanced efficacy of GNeo-IDUA was not the result of increased nose-to-brain delivery or enzyme stability, but rather due to more efficient uptake into neurons and astrocytes. GNeo conjugation also enhanced glycosaminoglycan clearance by intranasally delivered sulfamidase to the brain of sulfamidase-deficient mice, a model of Mucopolysaccharidosis IIIA. These findings suggest the general utility of the guanidinoglycoside-based delivery system for restoring missing lysosomal enzymes in the brain.

Review of transmission routes of 24 infectious diseases preventable by biosecurity measures and comparison of the implementation of these measures in pig herds in six European countries

This study aimed to review the transmission routes of important infectious pig diseases and to translate these into biosecurity measures preventing or reducing the transmission between and within pig herds. Furthermore, it aimed to identify the level of implementation of these measures in different European countries and discuss the observed variations to identify potentials for improvement. First, a literature review was performed to show which direct and indirect transmission routes of 24 infectious pig diseases can be prevented through different biosecurity measures. Second, a quantitative analysis was performed using the Biocheck.UGent™, a risk-based scoring system to evaluate biosecurity in pig herds, to obtain an insight into the implementation of these biosecurity measures. The database contained farm-specific biosecurity data from 574 pig farms in Belgium, Denmark, France, Germany, the Netherlands and Sweden, entered between January 2014 and January 2016. Third, a qualitative analysis based on a review of literature and other relevant information resources was performed for every subcategory of internal and external biosecurity in the Biocheck.UGent™ questionnaire. The quantitative analysis indicated that at the level of internal, external and overall biosecurity, Denmark had a significantly distinct profile with higher external biosecurity scores and less variation than the rest of the countries. This is likely due to a widely used specific pathogen-free (SPF) system with extensive focus on biosecurity since 1971 in Denmark. However, the observed pattern may also be attributed to differences in data collection methods. The qualitative analysis identified differences in applied policies, legislation, disease status, pig farm density, farming culture and habits between countries that can be used for shaping country-specific biosecurity advice to attain improved prevention and control of important pig diseases in European pig farms.

The impact of antimicrobial use guidelines on prescription habits in fourteen Flemish small animal practices

A prospective study was performed to explore the prescription habits in fourteen first-line, small animal practices during first consultations of cats and dogs. Consultations one month prior to the implementation of antimicrobial use guidelines and at least 20 days thereafter were examined. Differences in the proportion of consultations during which antimicrobials were prescribed, were assessed. Additionally, changes in the choice of active substance were critically evaluated against the introduced antimicrobial use guidelines. The proportion of consultations where antimicrobials were prescribed decreased in cats and dogs (both –12%) after the introduction of the antimicrobial use guidelines. There was an increase of consultations of cats (+13%) and dogs (+10%) where veterinarians handled according to those guidelines. However, an increase in the prescription of third-choice antimicrobials and highest priority critically important antimicrobials was noticed both in cats (+8% and +12%, respectively) and dogs (both +5%). This unexpected increase invites to create extra awareness amongst prescribers.

Overall Structural Model of NS5A Protein from Hepatitis C Virus and Modulation by Mutations Confering Resistance of Virus Replication to Cyclosporin A

Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) is a RNA-binding phosphoprotein composed of a N-terminal membrane anchor (AH), a structured domain 1 (D1), and two intrinsically disordered domains (D2 and D3). The knowledge of the functional architecture of this multifunctional protein remains limited. We report here that NS5A-D1D2D3 produced in a wheat germ cell-free system is obtained under a highly phosphorylated state. Its NMR analysis revealed that these phosphorylations do not change the disordered nature of D2 and D3 domains but increase the number of conformers due to partial phosphorylations. By combining NMR and small angle X-ray scattering, we performed a comparative structural characterization of unphosphorylated recombinant D2 domains of JFH1 (genotype 2a) and the Con1 (genotype 1b) strains produced in Escherichia coli. These analyses highlighted a higher intrinsic folding of the latter, revealing the variability of intrinsic conformations in HCV genotypes. We also investigated the effect of D2 mutations conferring resistance of HCV replication to cyclophilin A (CypA) inhibitors on the structure of the recombinant D2 Con1 mutants and their binding to CypA. Although resistance mutations D320E and R318W could induce some local and/or global folding perturbation, which could thus affect the kinetics of conformer interconversions, they do not significantly affect the kinetics of CypA/D2 interaction measured by surface plasmon resonance (SPR). The combination of all our data led us to build a model of the overall structure of NS5A, which provides a useful template for further investigations of the structural and functional features of this enigmatic protein.

Reducing Antimicrobial Usage in Pig Production without Jeopardizing Production Parameters

Antimicrobial usage (AMU) has been described to be high in pig production. Although farmers are aware of the high usage, little is known about intervention to improve the situation. This study evaluated the extent to which AMU could be reduced in pig production by the optimization of herd management, biosecurity status, vaccination strategy, anthelmintic therapy and advice on prudent AMU. Furthermore, the effects of these interventions on the herd production results were explored. This intervention study was conducted on 61 Flemish pig herds and included three visits per herd. During the initial visit, information was gathered on herd management, biosecurity status (quantified by means of the Biocheck.UGent^™ risk-based scoring system), vaccination strategy, anthelmintic therapy and AMU. This info was then translated into a herd-specific action plan which was discussed with the farmer and herd veterinarian/other advisors during the second visit. In the final herd visit (±8 months later), comparable data were obtained to evaluate the progress. Overall, a significant improvement of 2.4 points external and 7 points internal biosecurity on the herds was obtained, combined with additional vaccination, anthelmintic therapy and prudent AMU. This was accompanied by a significant reduction in the AMU with a decrease of 52% for the pigs from birth till slaughter and 32% for breeding animals, based on treatment incidences (TIs) and included an important reduction in the use of critically important antimicrobials. More importantly, the increased biosecurity levels and decreased AMU were combined with significantly improved technical results such as the number of weaned piglets per sow per year (+1.1), daily weight gain (+5.9 g/day) and mortality in the finisher period (-0.6%). Guided interventions as a team effort of farmer and herd veterinarian/other advisors have shown to be a promising method in the reduction of AMU in pig production.

Assessment of two essential elements of BVDV control on selected Flemish dairy and beef farms

Bovine viral diarrhea virus (BVDV) is one of the most important viruses to cause disease in cattle worldwide. The virus is endemically present in Belgium. Clinical diagnosis of BVDV infection is difficult. Therefore, monitoring through testing is necessary to detect the presence of the virus on farms. As vaccination alone does not suffice for eradication, a combination of measures is required for successful control. Via a questionnaire, the BVDV policy on 241 selected Flemish cattle farms was investigated. This revealed some striking results. For the majority of the herds, the BVDV status was unknown (63%), and only 23% had a monitoring program in place. Furthermore, on seven out of ten (71%) BVDV-vaccinating farms, vaccination against BVDV was implemented as a strategy without knowing the actual BVDV status.

Insights into the mechanism by which interferon-γ basic amino acid clusters mediate protein binding to heparan sulfate

The extensive functional repertoire of heparin and heparan sulfate, which relies on their ability to interact with a large number of proteins, has recently emerged. To understand the forces that drive such interactions the binding of heparin to interferon-γ (IFNγ), used as a model system, was investigated. NMR-based titration experiments demonstrated the involvement of two adjacent cationic domains (D1: KTGKRKR and D2: RGRR), both of which are present within the carboxy-terminal sequence of the cytokine. Kinetic analysis showed that these two domains contribute differently to the interaction: D1 is required to form a complex and constitutes the actual binding site, whereas D2, although unable to associate with heparin by itself, increased the association rate of the binding. These data are consistent with the view that D2, through nonspecific electrostatic forces, places the two molecules in favorable orientations for productive binding within the encounter complex. This mechanism was supported by electrostatic potential analysis and thermodynamic investigations. They showed that D1 association to heparin is driven by both favorable enthalpic and entropic contributions, as expected for a binding sequence, but that D2 gives rise to entropic penalty, which opposes binding in a thermodynamic sense. The binding mechanism described herein, by which the D2 domain kinetically drives the interaction, has important functional consequences and gives a structural framework to better understand how specific are the interactions between proteins and heparin.

Spontaneous bleeding in a neonatal calf persistently infected with BVDV1b

A calf developed skin bleeding on the second day of its life. It was referred to the clinic onsuspicion of bovine neonatal pancytopenia (BNP). Hematology showed extreme thrombocytopenia,moderate anemia, but no leukopenia. A PCR test on a heparinized blood sample was bovine viraldiarrhea virus (BVDV) positive, as were the two BVDV antigen ELISAs performed three and tenweeks later. Non-cytopathic BVDV type 1b was isolated from the blood. Although the calf recoveredfrom hemorrhagic disease, and continued to be healthy, it was euthanized at eleven weeks of agebecause of persistent BVDV infection. On the basis of the case history, BNP could be excludedfrom the differential diagnosis. This case illustrates that hemorrhagic disease is not exclusivelyassociated with BVDV type 2 and that the clinical signs in neonatal calves infected with BVDV1bcan be identical to the clinical presentation of BNP.

Molecular characteristics of Human Endogenous Retrovirus type-W in schizophrenia and bipolar disorder

Epidemiological and genome-wide association studies of severe psychiatric disorders such as schizophrenia (SZ) and bipolar disorder (BD), suggest complex interactions between multiple genetic elements and environmental factors. The involvement of genetic elements such as Human Endogenous Retroviruses type 'W' family (HERV-W) has consistently been associated with SZ. HERV-W envelope gene (env) is activated by environmental factors and encodes a protein displaying inflammation and neurotoxicity. The present study addressed the molecular characteristics of HERV-W env in SZ and BD. Hundred and thirty-six patients, 91 with BD, 45 with SZ and 73 healthy controls (HC) were included. HERV-W env transcription was found to be elevated in BD (P<10-4) and in SZ (P=0.012) as compared with HC, but with higher values in BD than in SZ group (P<0.01). The corresponding DNA copy number was paradoxically lower in the genome of patients with BD (P=0.0016) or SZ (P<0.0003) than in HC. Differences in nucleotide sequence of HERV-W env were found between patients with SZ and BD as compared with HC, as well as between SZ and BD. The molecular characteristics of HERV-W env also differ from what was observed in Multiple Sclerosis (MS) and may represent distinct features of the genome of patients with BD and SZ. The seroprevalence for Toxoplasma gondii yielded low but significant association with HERV-W transcriptional level in a subgroup of BD and SZ, suggesting a potential role in particular patients. A global hypothesis of mechanisms inducing such major psychoses is discussed, placing HERV-W at the crossroads between environmental, genetic and immunological factors. Thus, particular infections would act as activators of HERV-W elements in earliest life, resulting in the production of an HERV-W envelope protein, which then stimulates pro-inflammatory and neurotoxic cascades. This hypothesis needs to be further explored as it may yield major changes in our understanding and treatment of severe psychotic disorders.

A genetic model of substrate reduction therapy for mucopolysaccharidosis

Inherited defects in the ability to catabolize glycosaminoglycans result in lysosomal storage disorders known as mucopolysaccharidoses (MPS), causing severe pathology, particularly in the brain. Enzyme replacement therapy has been used to treat mucopolysaccharidoses; however, neuropathology has remained refractory to this approach. To test directly whether substrate reduction might be feasible for treating MPS disease, we developed a genetic model for substrate reduction therapy by crossing MPS IIIa mice with animals partially deficient in heparan sulfate biosynthesis due to heterozygosity in Ext1 and Ext2, genes that encode the copolymerase required for heparan sulfate chain assembly. Reduction of heparan sulfate by 30-50% using this genetic strategy ameliorated the amount of disease-specific biomarker and pathology in multiple tissues, including the brain. In addition, we were able to demonstrate that substrate reduction therapy can improve the efficacy of enzyme replacement therapy in cell culture and in mice. These results provide proof of principle that targeted inhibition of heparan sulfate biosynthetic enzymes together with enzyme replacement might prove beneficial for treating mucopolysaccharidoses.

Secondary storage of dermatan sulfate in Sanfilippo disease

Mucopolysaccharidoses are a group of genetically inherited disorders that result from the defective activity of lysosomal enzymes involved in glycosaminoglycan catabolism, causing their intralysosomal accumulation. Sanfilippo disease describes a subset of mucopolysaccharidoses resulting from defects in heparan sulfate catabolism. Sanfilippo disorders cause severe neuropathology in affected children. The reason for such extensive central nervous system dysfunction is unresolved, but it may be associated with the secondary accumulation of metabolites such as gangliosides. In this article, we describe the accumulation of dermatan sulfate as a novel secondary metabolite in Sanfilippo. Based on chondroitinase ABC digestion, chondroitin/dermatan sulfate levels in fibroblasts from Sanfilippo patients were elevated 2-5-fold above wild-type dermal fibroblasts. Lysosomal turnover of chondroitin/dermatan sulfate in these cell lines was significantly impaired but could be normalized by reducing heparan sulfate storage using enzyme replacement therapy. Examination of chondroitin/dermatan sulfate catabolic enzymes showed that heparan sulfate and heparin can inhibit iduronate 2-sulfatase. Analysis of the chondroitin/dermatan sulfate fraction by chondroitinase ACII digestion showed dermatan sulfate storage, consistent with inhibition of iduronate 2-sulfatase. The discovery of a novel storage metabolite in Sanfilippo patients may have important implications for diagnosis and understanding disease pathology.

Cooperative, heparan sulfate-dependent cellular uptake of dimeric guanidinoglycosides

Oligoarginine and guanidinium-rich molecular transporters have been shown to facilitate the intracellular delivery of a diverse range of biologically relevant cargos. Several such transporters have been suggested to interact with cell-surface heparan sulfate proteoglycans as part of their cell-entry pathway. Unlike for other guanidinium-rich transporters, the cellular uptake of guanidinoglycosides at nanomolar concentrations is exclusively heparan sulfate dependent. As distinct cells differ in their expression levels and/or the composition of cell-surface heparan sulfate proteoglycans, one might be able to exploit such differences to selectively target certain cell types. To systematically investigate the nature of their cell-surface interactions, monomeric and dimeric guanidinoglycosides were synthesized by using neomycin, paromomycin, and tobramycin as scaffolds. These transporters differ in the number and 3D arrangement of their guanidinium groups. Their cellular uptake was measured by flow cytometry in wild-type and mutant Chinese hamster ovary cells after the corresponding fluorescent streptavidin-phycoerythrin-Cy5 conjugates had been generated. All derivatives showed negligible uptake in mutant cells lacking heparan sulfate. Decreasing the number of guanidinium groups diminished uptake, but the three dimensional arrangement of these groups was less important for cellular delivery. Whereas conjugates prepared with the monomeric carriers showed significantly reduced uptake in mutant cells expressing heparan sulfate chains with altered patterns of sulfation, conjugates prepared with the dimeric guanidinoglycosides could overcome this deficiency and maintain high levels of uptake in such deficient cells. This finding suggests that cellular uptake depends on the valency of the transporter and both the content and arrangement of the sulfate groups on the cell-surface receptors. Competition studies with chemically desulfated or carboxy-reduced heparin derivatives corroborated these observations. Taken together, these findings show that increasing the valency of the transporters retains heparan sulfate specificity and provides reagents that could distinguish different cell types based on the specific composition of their cell-surface heparan sulfate proteoglycans.

Hijacking of the pleiotropic cytokine interferon-γ by the type III secretion system of Yersinia pestis

Yersinia pestis, the causative agent of bubonic plague, employs its type III secretion system to inject toxins into target cells, a crucial step in infection establishment. LcrV is an essential component of the T3SS of Yersinia spp, and is able to associate at the tip of the secretion needle and take part in the translocation of anti-host effector proteins into the eukaryotic cell cytoplasm. Upon cell contact, LcrV is also released into the surrounding medium where it has been shown to block the normal inflammatory response, although details of this mechanism have remained elusive. In this work, we reveal a key aspect of the immunomodulatory function of LcrV by showing that it interacts directly and with nanomolar affinity with the inflammatory cytokine IFNγ. In addition, we generate specific IFNγ mutants that show decreased interaction capabilities towards LcrV, enabling us to map the interaction region to two basic C-terminal clusters of IFNγ. Lastly, we show that the LcrV-IFNγ interaction can be disrupted by a number of inhibitors, some of which display nanomolar affinity. This study thus not only identifies novel potential inhibitors that could be developed for the control of Yersinia-induced infection, but also highlights the diversity of the strategies used by Y. pestis to evade the immune system, with the hijacking of pleiotropic cytokines being a long-range mechanism that potentially plays a key role in the severity of plague.

Heparan sulfate mimicry: a synthetic glycoconjugate that recognizes the heparin binding domain of interferon-gamma inhibits the cytokine activity

Cell-associated heparan sulfate (HS) is endowed with the remarkable ability to bind numerous proteins. As such, it represents a unique system that integrates signaling from circulating ligands with cellular receptors. This polysaccharide is extraordinary complex, and examples that define the structure-function relationship of HS are limited. In particular, it remains difficult to understand the structures by which HS interact with proteins. Among them, interferon-gamma (IFNgamma), a dimeric cytokine, binds to a complex oligosaccharide motif encompassing a N-acetylated glucosamine-rich domain and two highly sulfated sequences, each of which binds to one IFNgamma monomer. Based on this template, we have synthesized a set of glycoconjugate mimetics and evaluated their ability to interact with IFNgamma. One of these molecules, composed of two authentic N-sulfated octasaccharides linked to each other through a 50-Angstroms-long spacer termed 2O(10), displays high affinity for the cytokine and inhibits IFNgamma-HS binding with an IC(50) of 35-40 nm. Interestingly, this molecule also inhibits the binding of IFNgamma to its cellular receptor. Thus, in addition to its ability to delocalize the cytokine from cell surface-associated HS, this compound has direct anti-IFNgamma activity. Altogether, our results represent the first synthetic HS-like molecule that targets a cytokine, strongly validating the HS structural determinants for IFNgamma recognition, providing a new strategy to inhibit IFNgamma in a number of diseases in which the cytokine has been identified as a target, and reinforcing the view that it is possible to create"tailor-made"sequences based on the HS template to isolate therapeutic activities.

Endocan or endothelial cell specific molecule-1 (ESM-1): a potential novel endothelial cell marker and a new target for cancer therapy

Endocan, previously called endothelial cell specific molecule-1, is a soluble proteoglycan of 50 kDa, constituted of a mature polypeptide of 165 amino acids and a single dermatan sulphate chain covalently linked to the serine residue at position 137. This dermatan sulphate proteoglycan, which is expressed by the vascular endothelium, has been found freely circulating in the bloodstream of healthy subjects. Experimental evidence is accumulating that implicates endocan as a key player in the regulation of major processes such as cell adhesion, in inflammatory disorders and tumor progression. Inflammatory cytokines such as TNF-alpha, and pro-angiogenic growth factors such as VEGF, FGF-2 and HGF/SF, strongly increased the expression, synthesis or the secretion of endocan by human endothelial cells. Endocan is clearly overexpressed in human tumors, with elevated serum levels being observed in late-stage lung cancer patients, as measured by enzyme-linked immunoassay, and with its overexpression in experimental tumors being evident by immunohistochemistry. Recently, the mRNA levels of endocan have also been recognized as being one of the most significant molecular signatures of a bad prognosis in several types of cancer including lung cancer. Overexpression of this dermatan sulphate proteoglycan has also been shown to be directly involved in tumor progression as observed in mouse models of human tumor xenografts. Collectively, these results suggest that endocan could be a biomarker for both inflammatory disorders and tumor progression as well as a validated therapeutic target in cancer. On the basis of the recent successes of immunotherapeutic approaches in cancer, the preclinical data on endocan suggests that an antibody raised against the protein core of endocan could be a promising cancer therapy.

Synthesis of Tailor-Made Glycoconjugate Mimetics of Heparan Sulfate That Bind IFN-γ in the Nanomolar Range

We have recently described the preparation of three building blocks for the combinatorial synthesis of heparan sulfate (HS) fragments. Herein we show that one of these building blocks (disaccharide 4) allows the preparation, in high yields and with total alpha stereoselectivity, of tetra-, hexa- and octasaccharides from the heparin (HP) regular region, by using 2+2, 2+4 and 4+4 glycosylation strategies, respectively. These oligosaccharides were processed into sulfated derivatives bearing an allyl moiety in the anomeric position. The UV-promoted conjugation of these compounds with alpha,omega-bis(thio)poly(ethylene glycol) spacers of three different lengths allowed us to prepare nine benzylated glycoconjugates. After final deprotection, the glycoconjugates 1 a-c, 2 a-c and 3 a-c were obtained and their ability to inhibit the interaction between IFN-gamma and HP was tested by using surface plasmon resonance detection. Compound 3 b, containing two HP octasaccharides linked by a 50-A linker was able to inhibit the IFN-gamma/HP interaction with an IC(50) value of approximately 35 nM. In addition, the nine glycoconjugates were perfect tools in the study to ascertain the topology of the IFN-gamma binding site on HS. Compounds 1 a-c, 2 a-c and 3 a-c, by mimicking the alternating sulfated and nonsulfated regions found in HS, thus comprise the first example of a library of synthetic HS mimetics giving access to the "second level of molecular diversity" found in HS.

Tissue-specificity of 412 retrotransposon expression in Drosophila simulans and D. melanogaster

We analyse the expression of the retrotransposon 412 in the soma, testes, and ovaries in populations of Drosophila simulans and D. melanogaster, using RT-PCR and in situ hybridization. We find that expression of 412 is highly variable in the soma, confirming previous findings based on Northern blots. No 412RNA is detected in the ovaries by either in situ hybridization or RT-PCR, in any population of either species. Transcripts are, however, detected in the male germline, which show a very characteristic spatial pattern of 412 expression in primary spermatocytes. There is no relationship between expression of the 412 element in the soma and in the testes in the populations. These findings show that the expression of 412 is independently regulated in the soma and the testes, and this raises the question of the real influence of the somatic transcripts on the organism and on the transposition rate.

Negative and translation termination-dependent positive control of FLI-1 protein synthesis by conserved overlapping 5' upstream open reading frames in Fli-1 mRNA

The proto-oncogene Fli-1 encodes a transcription factor of the ets family whose overexpression is associated with multiple virally induced leukemias in mouse, inhibits murine and avian erythroid cell differentiation, and induces drastic perturbations of early development in Xenopus. This study demonstrates the surprisingly sophisticated regulation of Fli-1 mRNA translation. We establish that two FLI-1 protein isoforms (of 51 and 48 kDa) detected by Western blotting in vivo are synthesized by alternative translation initiation through the use of two highly conserved in-frame initiation codons, AUG +1 and AUG +100. Furthermore, we show that the synthesis of these two FLI-1 isoforms is regulated by two short overlapping 5' upstream open reading frames (uORF) beginning at two highly conserved upstream initiation codons, AUG -41 and GUG -37, and terminating at two highly conserved stop codons, UGA +35 and UAA +15. The mutational analysis of these two 5' uORF revealed that each of them negatively regulates FLI-1 protein synthesis by precluding cap-dependent scanning to the 48- and 51-kDa AUG codons. Simultaneously, the translation termination of the two 5' uORF appears to enhance 48-kDa protein synthesis, by allowing downstream reinitiation at the 48-kDa AUG codon, and 51-kDa protein synthesis, by allowing scanning ribosomes to pile up and consequently allowing upstream initiation at the 51-kDa AUG codon. To our knowledge, this is the first example of a cellular mRNA displaying overlapping 5' uORF whose translation termination appears to be involved in the positive control of translation initiation at both downstream and upstream initiation codons.

Spi-1/PU.1 is a positive regulator of the Fli-1 gene involved in inhibition of erythroid differentiation in friend erythroleukemic cell lines

Spi-1/PU.1 and Fli-1 are two members of the ETS family of transcription factors whose expression is deregulated by proviral insertion in most erythroleukemic cell lines induced by the spleen focus-forming virus (SFFV) and Friend murine leukemia virus (F-MuLV) components of the Friend viral complex, respectively. In this study, we present evidence that transcription of the Fli-1 gene is positively regulated by Spi-1/PU.1 in SFFV-transformed cell lines: (i) all SFFV-transformed cell lines expressing Spi-1/PU.1 are characterized by a specific pattern of Fli-1 gene transcripts initiated in the -200 region instead of position -400 as reported for F-MuLV-transformed cell lines; (ii) these Fli-1 transcripts initiated in the -200 region are downregulated in parallel with that of Spi-1/PU.1 during hexamethylenebisacetamide (HMBA) induced differentiation; and (iii) Fli-1 transcription is upregulated in SFFV cells lines following stable transfection of a Spi-1/PU.1 expression vector. Furthermore, we found by transient transfection assays that the -270/-41 region of the Fli-1 gene displays promoter activity which is transactivated by Spi-1/PU.1. This promoter is strictly dependent on the integrity of two highly conserved ETS DNA binding sites that bind the Spi-1/PU.1 protein in vitro. Finally, we show that transfection of constitutive or inducible Fli-1 expression vectors in SFFV-transformed cells inhibits their erythroid differentiation induced by HMBA. Overall, these data indicate that Fli-1 is a target gene of the Spi-1/PU.1 transcription factor in SFFV-transformed cell lines. We further suggest that deregulated synthesis of Fli-1 may trigger a common mechanism contributing to erythroleukemia induced by either SFFV or F-MuLV.

Evidence for interactions between rat hepatoma cell apoptosis and differentiation

Partial copper depletion of a variant rat hepatoma cell line induces a transient inhibition of growth and the genesis of stable, well-differentiated revertants. We report a burst of cell death, synchronous with the peak of reversion. The characteristics of this cell mortality were typical of apoptosis and included detachment from the plastic support, chromatin condensation and fragmentation, and internucleosomal DNA degradation. Although commitment to cell death was induced by copper deficiency, the apoptotic process was partially inhibited as assessed from electrophoretic patterns of DNA degradation. Redifferentiation was closely linked to the apoptotic death program. Analysis of rescued detached cells in all three media (standard, Cu-, Fe-) indicated that the frequency of revertants was significantly higher among floating as opposed to adherent cell populations. Nevertheless, experimental copper depletion increased by 10(4) times the revertant frequency among adherent cells. We propose that redifferentiation of the variant hepatoma cells (and concomitant recovery of tumorigenicity) is determined by the gene expression pattern of programmed cell death.

The time-pattern of rises and falls in proliferation fades with senescence of mortal lines and is perpetuated in immortal rat hepatoma Fao cell line

Immortal cells perpetuate the rises and falls of proliferation that are progressively damped in mortal long-term cultured cells. For immortal rat hepatoma Fao cells, similar waves of proliferation occurred about every 3-4 wk. Under the same conditions, embryonic human fibroblasts and transformed but not immortalized embryonic fibroblasts display similarly recurring proliferation waves that progressively decrease in amplitude until senescence of the lines. In addition, strains of diploid normal human skin fibroblasts cultured under different culture conditions display a similar time-pattern of proliferation. Although the amplitude and baseline of these fluctuations are characteristic for each cell line, a common point was marked slow down in proliferation after every sequence of about 25 population doublings for all cells. Renewed proliferation waves of Fao cells allow about 22-23 additional population doublings each. Normal embryonic fibroblast culture and its transformed counterpart accumulate about 30 and 60 population doublings, respectively, before senescence. Normal fibroblast strains accumulate about 25 population doublings over their entire life spans. This halt in proliferation after every stretch of about 25 population doublings may correspond to a structural or functional stop following attrition of telomeric DNA. This putative stop may be bypassed once in transformed embryonic cells and repetitively in immortal cells. In support of this hypothesis, we observed rapid telomere shortening, in two steps, during divisions of mortal embryonic cells, and maintenance of long telomeres in immortal Fao cells, which may indicate episodic repair of telomeres. Alternatively, such maintenance of long telomeres may reflect survival and successive clonal growth of rare cells with long telomeres. We suggest that the balance between telomere attrition and repair processes regulates the waves of proliferation.

Extinction of peroxisomal functions in hepatoma cell-fibroblast hybrids

Although peroxisomes are ubiquitous, differences in the number of organelles and in the expression of associated metabolic activities are observed, depending on the cell type. To investigate the control of peroxisomal activity in connection with cell differentiation, we constructed hybrids between two types of cells whose histogenetic origins dictate significant differences in peroxisomal activities: hepatoma cells and fibroblasts, with high and low expression, respectively, of peroxisomal functions. In these hybrids, extinction of the elevated activities that characterize liver cells is observed, in parallel with the well-documented extinction of differentiated functions. This suggests the existence in fibroblasts of a negative trans-acting regulation.

Application of spheroid culture to human hepatocytes and maintenance of their differentiation

Human hepatocytes cultured with a hormonally defined medium on non-adherent poly-(2-hydroxyethyl methacrylate)-coated surface were able to form spheroids. The maintenance of liver-specific functions was assessed by following secretion of albumin, transferrin and alpha 1-antitrypsin that were still detectable after 4 months of spheroidal culture. Moreover, cytochrome P-450 IA was induced by methylcholanthrene for up to 2 weeks. This cell system is very promising for long-term in vitro studies of human hepatocyte functions.