Reference Data Set for Circular Dichroism Spectroscopy Comprised of Validated Intrinsically Disordered Protein Models

Circular dichroism (CD) spectroscopy is an analytical technique that measures the wavelength-dependent differential absorbance of circularly polarized light and is applicable to most biologically important macromolecules, such as proteins, nucleic acids, and carbohydrates. It serves to characterize the secondary structure composition of proteins, including intrinsically disordered proteins, by analyzing their recorded spectra. Several computational tools have been developed to interpret protein CD spectra. These methods have been calibrated and tested mostly on globular proteins with well-defined structures, mainly due to the lack of reliable reference structures for disordered proteins. It is therefore still largely unclear how accurately these computational methods can determine the secondary structure composition of disordered proteins. Here, we provide such a required reference data set consisting of model structural ensembles and matching CD spectra for eight intrinsically disordered proteins. Using this set of data, we have assessed the accuracy of several published CD prediction and secondary structure estimation tools, including our own CD analysis package, SESCA. Our results show that for most of the tested methods, their accuracy for disordered proteins is generally lower than for globular proteins. In contrast, SESCA, which was developed using globular reference proteins, but was designed to be applicable to disordered proteins as well, performs similarly well for both classes of proteins. The new reference data set for disordered proteins should allow for further improvement of all published methods.

Amino Acid Residues Controlling Domain Interaction and Interdomain Electron Transfer in Cellobiose Dehydrogenase

The function of cellobiose dehydrogenase (CDH) in biosensors, biofuel cells, and as a physiological redox partner of lytic polysaccharide monooxygenase (LPMO) is based on its role as an electron donor. Before donating electrons to LPMO or electrodes, an interdomain electron transfer from the catalytic FAD-containing dehydrogenase domain to the electron shuttling cytochrome domain of CDH is required. This study investigates the role of two crucial amino acids located at the dehydrogenase domain on domain interaction and interdomain electron transfer by structure-based engineering. The electron transfer kinetics of wild-type Myriococcum thermophilum CDH and its variants M309A, R698S, and M309A/R698S were analyzed by stopped-flow spectrophotometry and structural effects were studied by small-angle X-ray scattering. The data show that R698 is essential to pull the cytochrome domain close to the dehydrogenase domain and orient the heme propionate group towards the FAD, while M309 is an integral part of the electron transfer pathway - its mutation reducing the interdomain electron transfer 10-fold. Structural models and molecular dynamics simulations pinpoint the action of these two residues on the domain interaction and interdomain electron transfer.

Detection of antinuclear antibodies: recommendations from EFLM, EASI and ICAP

OBJECTIVES

Antinuclear antibodies (ANA) are important for the diagnosis of various autoimmune diseases. ANA are usually detected by indirect immunofluorescence assay (IFA) using HEp-2 cells (HEp-2 IFA). There are many variables influencing HEp-2 IFA results, such as subjective visual reading, serum screening dilution, substrate manufacturing, microscope components and conjugate. Newer developments on ANA testing that offer novel features adopted by some clinical laboratories include automated computer-assisted diagnosis (CAD) systems and solid phase assays (SPA).

METHODS

A group of experts reviewed current literature and established recommendations on methodological aspects of ANA testing. This process was supported by a two round Delphi exercise. International expert groups that participated in this initiative included (i) the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group "Autoimmunity Testing"; (ii) the European Autoimmune Standardization Initiative (EASI); and (iii) the International Consensus on ANA Patterns (ICAP).

RESULTS

In total, 35 recommendations/statements related to (i) ANA testing and reporting by HEp-2 IFA; (ii) HEp-2 IFA methodological aspects including substrate/conjugate selection and the application of CAD systems; (iii) quality assurance; (iv) HEp-2 IFA validation/verification approaches and (v) SPA were formulated. Globally, 95% of all submitted scores in the final Delphi round were above 6 (moderately agree, agree or strongly agree) and 85% above 7 (agree and strongly agree), indicating strong international support for the proposed recommendations.

CONCLUSIONS

These recommendations are an important step to achieve high quality ANA testing.

Neurologic manifestations of COVID-19 in critically ill patients: results of the prospective multicenter registry PANDEMIC

Background

Neurologic manifestations are increasingly reported in patients with coronavirus disease 2019 (COVID-19). Yet, data on prevalence, predictors and relevance for outcome of neurological manifestations in patients requiring intensive care are scarce. We aimed to characterize prevalence, risk factors and impact on outcome of neurologic manifestations in critically ill COVID-19 patients.

Methods

In the prospective, multicenter, observational registry study PANDEMIC (Pooled Analysis of Neurologic DisordErs Manifesting in Intensive care of COVID-19), we enrolled COVID-19 patients with neurologic manifestations admitted to 19 German intensive care units (ICU) between April 2020 and September 2021. We performed descriptive and explorative statistical analyses. Multivariable models were used to investigate factors associated with disorder categories and their underlying diagnoses as well as to identify predictors of outcome.

Results

Of the 392 patients included in the analysis, 70.7% (277/392) were male and the mean age was 65.3 (SD ± 3.1) years. During the study period, a total of 2681 patients with COVID-19 were treated at the ICUs of 15 participating centers. New neurologic disorders were identified in 350 patients, reported by these centers, suggesting a prevalence of COVID-19-associated neurologic disorders of 12.7% among COVID-19 ICU patients. Encephalopathy (46.2%; 181/392), cerebrovascular (41.0%; 161/392) and neuromuscular disorders (20.4%; 80/392) were the most frequent categories identified. Out of 35 cerebrospinal fluid analyses with reverse transcriptase PCR for SARS-COV-2, only 3 were positive. In-hospital mortality was 36.0% (140/389), and functional outcome (mRS 3 to 5) of surviving patients was poor at hospital discharge in 70.9% (161/227). Intracerebral hemorrhage (OR 6.2, 95% CI 2.5–14.9, p < 0.001) and acute ischemic stroke (OR 3.9, 95% CI 1.9–8.2, p < 0.001) were the strongest predictors of poor outcome among the included patients.

Conclusions

Based on this well-characterized COVID-19 ICU cohort, that comprised 12.7% of all severe ill COVID-19 patients, neurologic manifestations increase mortality and morbidity. Since no reliable evidence of direct viral affection of the nervous system by COVID-19 could be found, these neurologic manifestations may for a great part be indirect para- or postinfectious sequelae of the infection or severe critical illness. Neurologic ICU complications should be actively searched for and treated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04080-3.

AB0059 Src-LIKE ADAPTOR PROTEIN DEFICIENCY DOSE-DEPENDENTLY PROTECTS MICE AGAINST COLLAGEN-INDUCED ARTHRITIS

Background

Src-like adaptor protein (SLAP), an adaptor between E3 ubiquitin ligase c-Cbl and the TCR complex, is a negative regulator of T-cell activation. SLAP regulates the expression of the CD3 ζ-chain. In accordance with our previous data, SLAP expression is increased in the CD4+ T-cells of patients with rheumatoid arthritis (RA). Recent data demonstrate that SLAP deficiency can prevent zymosan-induced arthritis in mice.

Objectives

We investigated the role of SLAP in collagen-induced arthritis (CIA).

Methods

Homozygous and heterozygous SLAP knock out and wild type (WT) C57BL/6J mice were used. After the isolation of genomial DNA, the genotype of the mice was determined. Then the animals were injected once (primary immunization) or twice (secondary immunization) with type II. collagen, or left untreated (the first injection was applied together with complete Freund’s adjuvant). Mice were monitored twice a week for 70 days, and the severity scores were evaluated. The scores were calculated for each limb (1 limb score: 0=no swelling; 4=the severe swelling).

Results

SLAP deficiency provided almost complete protection from the primary immunization of CIA. By contrast secondary immunization led to similar arthritis of the SLAP-KO, heterozygous or WT mice.

Conclusion

The authors’ present data suggest that SLAP deficiency protects dose-dependently from CIA.

Acknowledgements

This work was supported by OTKA/NKFIHO NN 111023; OTKA/NKFIHN K 131479.

Disclosure of Interests

None declared

Folding of VemP into translation-arresting secondary structure is driven by the ribosome exit tunnel

The ribosome is a fundamental biomolecular complex that synthesizes proteins in cells. Nascent proteins emerge from the ribosome through a tunnel, where they may interact with the tunnel walls or small molecules such as antibiotics. These interactions can cause translational arrest with notable physiological consequences. Here, we studied the arrest caused by the regulatory peptide VemP, which is known to form α-helices inside the ribosome tunnel near the peptidyl transferase center under specific conditions. We used all-atom molecular dynamics simulations of the entire ribosome and circular dichroism spectroscopy to study the driving forces of helix formation and how VemP causes the translational arrest. To that aim, we compared VemP dynamics in the ribosome tunnel with its dynamics in solution. We show that the VemP peptide has a low helical propensity in water and that the propensity is higher in mixtures of water and trifluorethanol. We propose that helix formation within the ribosome is driven by the interactions of VemP with the tunnel and that a part of VemP acts as an anchor. This anchor might slow down VemP progression through the tunnel enabling α-helix formation, which causes the elongation arrest.

Effects of one-year tofacitinib therapy on bone metabolism in rheumatoid arthritis

Janus kinase (JAK) inhibitors are used to treat rheumatoid arthritis (RA). We assessed the effects of tofacitinib on bone density and bone markers in association with clinical and laboratory parameters in RA. Tofacitinib stabilized bone density and resulted in a positive balance of bone turnover.

INTRODUCTION

Janus kinase (JAK) inhibitors emerged as new therapeutic options in rheumatoid arthritis (RA). We have little information on how it affects areal and volumetric bone mineral density (BMD) and bone turnover markers. The aim of this study was to assess the effects of 1-year tofacitinib therapy on bone metabolism in RA.

METHODS

Thirty RA patients with active disease were treated with either 5 mg bid or 10 mg bid tofacitinib for 12 months. We determined DAS28, CRP, IgM rheumatoid factor (RF), and anti-cyclic citrullinated peptide (CCP) levels, as well as serum levels of sclerostin, osteocalcin (OC), P1NP, DKK-1, OPG, RANKL, and 25-hydroxy-vitamin D3. Areal and volumetric BMD were assessed by DXA and peripheral quantitative CT (QCT), respectively.

RESULTS

Twenty-six patients (13 on each arm) completed the study. Tofacitinib was clinically effective by suppressing DAS28, CRP, and HAQ. This was accompanied by the attenuation of further bone loss. Tofacitinib therapy significantly increased OC, OPG, and vitamin D3, while decreased CTX levels (p < 0.05). Age and multiple bone markers (OC, CTX, P1NP, RANKL) inversely correlated with L2-4 and femoral neck BMD by DXA. CRP, DAS28, and RANKL inversely determined volumetric BMD by QCT. Age, CRP, anti-CCP, and DKK-1 influenced the effects of tofacitinib therapy on BMD changes.

CONCLUSIONS

One-year tofacitinib treatment stabilized BMD in RA patients and resulted in a positive balance of bone turnover as indicated by bone biomarkers. Further studies are needed to evaluate the potential beneficial effects of JAK inhibitors on inflammatory bone loss.

Automated Pupillometry for Assessment of Treatment Success in Nonconvulsive Status Epilepticus

BACKGROUND

Altered pupillary function may reflect nonconvulsive status epilepticus (NCSE). Neurological pupil index (NPi) assessed by automated pupillometry is a surrogate marker of global pupillary function. We aimed to assess NPi changes in relation to NCSE treatment response.

METHODS

In this prospective observational study, serial automated pupillometry was performed in 68 NCSE episodes. In accordance with local standards, patients were treated with clonazepam (1-2 mg), levetiracetam (40 mg/kg), and lacosamide (5 mg/kg) in a stepwise approach under continuous electroencephalography monitoring until NCSE was terminated. Patients with refractory NCSE received individualized regimens. NPi was assessed bilaterally before and after each treatment step. For statistical analysis, the lower NPi of both sides (minNPi) was used. Nonparametric testing for matched samples and Cohen's d to estimate effect size were performed. Principal component analysis was applied to assess the contribution of baseline minNPi, age, sex, and NCSE duration to treatment outcome.

RESULTS

In 97.1% of 68 episodes, NCSE could be terminated; in 16.2%, NCSE was refractory. In 85.3% of episodes, an abnormal baseline minNPi ≤ 4.0 was obtained. After NCSE termination, minNPi increased significantly (p < 0.001). Cohen's d showed a strong effect size of 1.24 (95% confidence interval 0.88-1.61). Baseline minNPi was higher in clonazepam nonresponders vs. responders (p = 0.008), minNPi increased in responders (p < 0.001) but not in nonresponders. NCSE refractivity was associated with normal baseline minNPi (principal component analysis, component 1, 32.6% of variance, r = 0.78), male sex, and longer NCSE duration (component 2, 27.1% of variance, r = 0.62 and r = 0.78, respectively).

CONCLUSIONS

Automated pupillometry may be a helpful noninvasive neuromonitoring tool for the assessment of patients with NCSE and response to treatment.

Synthesis, radiolabeling, and pre-clinical evaluation of [44Sc]Sc-AAZTA conjugate PSMA inhibitor, a new tracer for high-efficiency imaging of prostate cancer

PURPOSE

The aim of this work was to demonstrate the suitability of AAZTA conjugated to PSMA inhibitor (B28110) labeled with scandium-44 as a new PET tracer for diagnostic imaging of prostate cancer.

BACKGROUND

Nowadays, scandium-44 has received significant attention as a potential radionuclide with favorable characteristics for PET applications. A polyaminopolycarboxylate heptadentate ligand based on a 1,4-diazepine scaffold (AAZTA) has been thoroughly studied as chelator for Gd³⁺ ions for MRI applications. The excellent results of the equilibrium, kinetic, and labeling studies led to a preliminary assessment of the in vitro and in vivo behavior of [⁴⁴Sc][Sc-(AAZTA)]^- and two derivatives, i.e., [⁴⁴Sc][Sc (CNAAZTA-BSA)] and [⁴⁴Sc][Sc (CNAAZTA-cRGDfK)].

RESULTS

B28110 was synthesized by hybrid approach, combining solid-phase peptide synthesis (SPPS) and solution chemistry to obtain high purity (97%) product with an overall yield of 9%. Subsequently, the radioactive labeling was performed with scandium-44 produced from natural calcium target in cyclotron, in good radiochemical yields (RCY) under mild condition (pH 4, 298 K). Stability study in human plasma showed good RCP% of [⁴⁴Sc]Sc-B28110 up to 24 h (94.32%). In vivo PET/MRI imaging on LNCaP tumor-bearing mice showed high tracer accumulation in the tumor regions as early as 20 min post-injection. Ex vivo biodistribution studies confirmed that the accumulation of ⁴⁴Sc-PSMA-617 was two-fold lower than that of the radiolabeled B28110 probes.

CONCLUSIONS

This work demonstrated the suitability of B28110 for the complexation with scandium-44 at room temperature and the high performance of the resulting new tracer based on AAZTA chelator for the diagnosis of prostate cancer using PET.

How accurate is circular dichroism-based model validation?

Circular dichroism (CD) spectroscopy is highly sensitive to the secondary structure (SS) composition of proteins. Several methods exist to either estimate the SS composition of a protein or to validate existing structural models using its CD spectrum. The accuracy and precision of these methods depend on the quality of both the measured CD spectrum and the used reference structure. Using a large reference protein set with high-quality CD spectra and synthetic data derived from this set, we quantified deviations from both ideal spectra and reference structures due to experimental limitations. We also determined the impact of these deviations on SS estimation, CD prediction, and SS validation methods of the SESCA analysis package. With regard to the CD spectra, our results suggest intensity scaling errors and non-SS contributions as the main causes of inaccuracies. These factors also can lead to overestimated model errors during validation. The errors of the used reference structures combine non-additively with errors caused by the CD spectrum, which increases the uncertainty of model validation. We have further shown that the effects of scaling errors in the CD spectrum can be nearly eliminated by appropriate re-scaling, and that the accuracy of model validation methods can be improved by accounting for typical non-SS contributions. These improvements have now been implemented within the SESCA package and are available at: https://www.mpibpc.mpg.de/sesca .

Expression of the Neuronal tRNA n-Tr20 Regulates Synaptic Transmission and Seizure Susceptibility

The mammalian genome has hundreds of nuclear-encoded tRNAs, but the contribution of individual tRNA genes to cellular and organismal function remains unknown. Here, we demonstrate that mutations in a neuronally enriched arginine tRNA, n-Tr20, increased seizure threshold and altered synaptic transmission. n-Tr20 expression also modulated seizures caused by an epilepsy-linked mutation in Gabrg2, a gene encoding a GABA_A receptor subunit. Loss of n-Tr20 altered translation initiation by activating the integrated stress response and suppressing mTOR signaling, the latter of which may contribute to altered neurotransmission in mutant mice. Deletion of a highly expressed isoleucine tRNA similarly altered these signaling pathways in the brain, suggesting that regulation of translation initiation is a conserved response to tRNA loss. Our data indicate that loss of a single member of a tRNA family results in multiple cellular phenotypes, highlighting the disease-causing potential of tRNA mutations.

Cerebrospinal fluid findings in COVID-19 patients with neurological symptoms

•

Largest cohort of patients with COVID-19 and neurological symptoms who underwent LP.

•

In all 30 cases, RT-PCR for SARS-CoV-2 from CSF was negative.

•

CSF analysis findings, including WBC, were normal in most patients with COVID-19.

•

Neurological symptoms in COVID-19 seem to be caused mainly by indirect mechanism.

FRI0047 STRATEGIES REGARDING GOAL SETTING AND SELF-MANAGEMENT IN DIFFICULT-TO-TREAT RHEUMATOID ARTHRITIS: PRELIMINARY RESULTS OF A SYSTEMATIC LITERATURE REVIEW INFORMING THE 2020 EULAR RECOMMENDATIONS FOR THE MANAGEMENT OF DIFFICULT-TO-TREAT RHEUMATOID ARTHRITIS

Background:

Rheumatoid arthritis (RA) patients treated according to European League Against Rheumatism (EULAR) recommendations failing ≥2 biological or targeted synthetic disease-modifying antirheumatic drugs with a different mode of action who still have complaints which may be suggestive of active disease and for whom management is perceived as problematic by patient and/or rheumatologist have been defined as suffering from ‘difficult-to-treat RA’. A mismatch in goal setting between patient and health care professional, and suboptimal self-management may contribute to this disease state, while specific management recommendations regarding these factors are currently lacking.1

Objectives:

To systematically summarise evidence in the literature on the identification and optimisation of a mismatch in goal setting and suboptimal self-management in difficult-to-treat RA patients, informing the 2020 EULAR recommendations for the management of difficult-to-treat RA.

Methods:

A systematic literature review (SLR) was performed: PubMed, Embase and Cochrane databases were searched up to December 2018. Relevant papers were selected and appraised. Effect sizes were extracted or calculated.

Results:

Three studies were selected on the identification and four on the optimisation of a mismatch in goal setting (Figure 1). No accurate measures were found to identify a mismatch in goal setting, but patients expressed a desire to take their quality of life goals more explicitly into account. Education was found to improve goal setting (4 of 4 studies, effect size not calculable).

Five studies were selected on the identification and 31 on the optimisation of suboptimal self-management (Figure 1). Although formal evaluations in high quality studies were lacking, the Arthritis Self-Efficacy Score was found to be the most reliable tool to identify suboptimal self-management. Patients were found to desire more education on nutrition, the disease and the diagnostic process to be able to improve self-management. Self-management programs, educational and psychological interventions were found to improve self-management (Table 1).

Table 1:

Effect sizes of studies on the optimisation of self-management

OutcomeType of interventionBenefit of intervention compared to control1innofnselected studiesStudies with effect size (n)Effect size per study2Self-efficacySelf-management programs12/1360.18−0.39; 0.23−0.67; 0.37; 0.43−0.53; 0.49;37.52−8.25Education6/630.05−0.17; 0.22−0.59; 1.23Psychological2/220.20−0.35; 0.45AnxietyPsychological1/210.173Depressive symptomsPsychological1/210.15−0.333RA knowledgeEducation3/320.34−0.47; 0.84

n: number of studies; RA: rheumatoid arthritis.

1. Mostly usual care or wait list; 2. If different outcome measures were used the range in effect sizes over these measures is reported; 3. Pooled effect size, reported in systematic literature review.

Conclusion:

In difficult-to-treat RA patients, limited evidence was found on a mismatch in goal setting and suboptimal self-management, especially regarding their identification. Non-pharmacological interventions were found to improve goal setting and self-management.

References:

[1]Smolen JSet al. Ann Rheum Dis2020. Epub ahead of print.

Disclosure of Interests:

Nadia M. T. Roodenrijs: None declared, Attila Hamar: None declared, Melinda Kedves: None declared, György Nagy: None declared, Jacob M. van Laar Grant/research support from: MSD, Genentech, Consultant of: MSD, Roche, Pfizer, Eli Lilly, BMS, Désirée van der Heijde Consultant of: AbbVie, Amgen, Astellas, AstraZeneca, BMS, Boehringer Ingelheim, Celgene, Cyxone, Daiichi, Eisai, Eli-Lilly, Galapagos, Gilead Sciences, Inc., Glaxo-Smith-Kline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, UCB Pharma; Director of Imaging Rheumatology BV, Paco Welsing: None declared

THU0356 DISEASE ACTIVITY ASSESSMENT IN SYSTEMIC SCLEROSIS PATIENTS BASED ON THE CURRENTLY AVAILABLE ACTIVITY INDICES AND THE PHYSICIAN GLOBAL ASSESSMENT

Background:

Disease activity assessment is crucial in defining the appropriate therapy and to monitor the efficacy of treatment in systemic sclerosis.

Objectives:

We aimed to test the performance of the ’old’ European Scleroderma Trials and Research Group (EUSTAR) Activity Index (old-AI) (1), the ’new’ EUSTAR activity index (new-AI) (2), and the scleroderma activity index derived from the old-AI (Pecs-AI) (3). We compared the three indices to the disease activity based on the physician’s global assessment (PGA). We also assessed the correlations with the change in modified Rodnan Skin Score (MRSS), FVC and arthritis after one year follow-up.

Methods:

We evaluated 77 patients (50 diffuse /dcSSc/ and 27 limited cutaneous SSc /lcSSc/ patients) from a single tertiary clinical center. Cohort enrichment was performed to increase the number of patients with early disease and dcSSc. Seventy-two patients were re-evaluated after one year. Nine patients had overlap syndromes: rheumatoid arthritis (n=3), Sjögren syndrome (n=2), polymyositis (n=2), and mixed connective tissue disease (n=2). The overall disease activity was evaluated using both composite indices (old-AI, Pecs-AI, new-AI) and the PGA of disease activity, based on the blinded evaluation of a single physician (LV). In addition to the minimal essential data from the EUSTAR database we also performed detailed assessment of the musculoskeletal involvement evaluating measures of hand function, DAS28 scores, and the Clinical Disease Activity Index (CDAI) (4).

Results:

Three times more patients with active disease were identified by the new-AI compared to the old-AI at baseline investigation (n=37, 48.7%, vs. n=11, 14.3%). Two patients (18%) with active disease based on the old-AI were missed by the new-AI. Pecs-AI index identified 15 patients (19.5%) with active disease (cut-off >2.75 points). Active disease was equally frequent in dcSSc and lcSSc patients based on old-AI, but was more frequent in dcSSc patients based on the new-AI in the whole cohort, and also after excluding overlap cases.

Patients with active disease based on the old-AI had more frequently rheumatoid factor (6/9, vs. 12/45, p=0.047), and DLCO<70% (11/11, vs. 36/65, p<0.01). Active disease based on the new-Al was associated with current cyclophosphamide treatment (9/37, vs.2/39, p=0.023), and diabetes mellitus (7/30, vs. 0/39, p<0.01). The PGA correlated moderately at both baseline and one year follow-up examination with the old-AI (rho: 0.519, and rho: 0.692, respectively, p<0.001), the new-AI (rho: 0.401, and rho: 0.429, respectively, p<0.001), and the Pecs-AI (rho: 0.425, and rho: 0.593, respectively, p<0.001).

CDAI correlated significantly with the old-AI (rho: 0.345, and rho: 0.283, respectively, p<0.05) and the Pecs-AI (rho: 0.363, and rho: 0.324, respectively, p<0.05) at both the baseline and one-year follow-up investigations, but showed no consistent correlation to the new-AI or PGA.

Conclusion:

The two validated disease activity indices indentify different patient groups. Joint involvement is potentially underrepresented in the new EUSTAR activity index. Active disease is also present in lcSSc and should be assessed regularly in these patients.

References:

[1]Valentini G, et al. Ann Rheum Dis 2003; 62: 901-3.

[2]Valentini G, et al. Ann Rheum Dis 2017;76:270–276.

[3]Minier T, et al. Rheumatology (Oxford) 2010;49(6):1133-45.

[4]Lorand V, et al. Rheumatology (Oxford). 2016;55(10):1849-58.

Acknowledgments:

This work was supported by the EU Seventh Framework Program [FP7/2007-2013] under Grant Agreement n° 305495 (DeSScipher), by the Hungarian Scientific Research Fund (contract n°: 112939), and the EU under the Grant Agreement n° PEPSYS GINOP-232-15-2016-00050.

Disclosure of Interests:

Tünde Minier Speakers bureau: Actelion, Abbvie, MSD, Pfizer, Lilly, Roche, Veronika Lóránd: None declared, Zsófia Bálint: None declared, Dalma Komjati: None declared, Gabriella Nagy Speakers bureau: MSD, Antonietta Kovács: None declared, Orsolya Koncz: None declared, Cecília Varjú Consultant of: Boehringer Ingelheim RCV GmbH & Co KG, Speakers bureau: Lilly, László Czirják Consultant of: Actelion, BI, Roche-Genentech, Lilly, Medac, Novartis, Pfizer, Bayer AG, Gabor Kumanovics Consultant of: Boehringer, Teva, Speakers bureau: Roche, Lilly, Novartis, Balazs Nemeth: None declared

THU0181 SOLUBLE VASCULAR BIOMARKERS IN RHEUMATOID ARTHRITIS AND ANKYLOSING SPONDYLITIS: EFFECTS OF ONE-YEAR ANTI-TNF-Α THERAPY

Background:

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) have been associated with inflammatory atherosclerosis, increased cardiovascular (CV) morbidity and mortality. Numerous proteins may serve as biomarkers of inflammatory atherosclerosis. The treatment of arthritis by tumour necrosis factor α (TNF-α) inhibitors may decrease the serum concentrations of these biomarkers.

Objectives:

In this study we wished to determine circulating levels of oxidized LDL (oxLDL) - β2 glycoprotein I (β2GPI) complexes (AtherOx), anti-hsp60 antibodies, soluble urokinase plasminogen activator receptor (sUPAR) and N-terminal B-type natriuretic peptide (NT-proBNP) in sera of RA and AS patients. We also wished to assess the effects of anti-TNF treatment on these biomarkers.

Methods:

Altogether 53 arthritis patients including 36 RA patients treated with either etanercept (ETN) or certolizumab pegol (CZP) and 17 AS patients treated with ETN were included in a 12-month follow-up study.Circulating oxLDL/β2gpI complexes, anti-human Hsp60 immunoglobulin G (IgG) levels and BNP8-29fragment levels were assessed by ELISA. suPAR levels were assessed by suPARnostic®Quick Triage test. All laboratory assessments were performed at baseline, as well as 6 and 12 months after treatment initiation. Results were associated with DAS28, BASDAI, CRP.

Results:

In the mixed cohort of 53 arthritis patients, the circulating levels of oxLDL/β2gpI significantly decreased after 12 months of anti-TNF therapy (0.20±0.11 U/ml) compared to baseline (0.24±0.10 U/ml; p=0.014). There was a tendency of non-significant decrease after 6 months (0.23±0.14 U/ml) versus baseline. Anti-Hsp60 antibody levels did not change after 6 months (158.6±138.6 AU/ml) and 12 months (167.3±143.3 AU/ml) compared to baseline (170.3±140.4 AU/ml). Among the patients, 21.2% had low, 36.4% “observe”, 9.1% high and 33.3% critical suPAR levels. suPAR levels showed a tendency of non-significant decrease after 6 months (11.3±17.7 ng/ml) and 12 months (10.3±15.3 ng/ml) versus baseline (11.5±16.4 ng/ml). However, when the four serum level categories described above were considered, suPAR concentrations exerted significant decrease in RA patients with critical suPAR levels (>9ng/ml) (p=0.04). Similarly, BNP fragment levels showed only a tendency of decrease after 6 months (518.2±422.4 pmol/l) and 12 months (484.1±418.2 pmol/l) versus baseline (530.8±441.8 pmol/l). However, serum BNP levels at baseline and after 12 months were significantly increased in CCP positive compared to CCP negative RA patients (baseline: 670.6±323.0 versus 138.0±436.4 pmol/l; p=0.030 and 12 months: 652.9±283.2 versus 456.5±423.1 pmol/l; p=0.021), as well as in RF positive compared to RF negative RA patients (baseline: 680.6±381.6 versus 292.9±198.3 pmol/l; p=0.007 and 12 months: 668.9±346.5 versus 312.2±207.0 pmol/l; p=0.001).

Conclusion:

One-year anti-TNF therapy significantly decreased circulating oxLDL/β2gpI complex levels. This therapy also decreased suPAR levels in patients with critically high suPAR. BNP fragment levels were associated with seropositivity in RA. These vascular biomarkers may reflect the effects of TNF inhibition on endothelial activation.

Acknowledgments:

This study was sponsored by an investigator-initiated grant from Pfizer.

Disclosure of Interests:

Anita Pusztai: None declared, Attila Hamar: None declared, Ágnes Horváth: None declared, Edit Végh: None declared, Nóra Bodnár: None declared, György Kerekes: None declared, Monika Czókolyová: None declared, Szilvia Szamosi: None declared, Levente Bodoki: None declared, Katalin Hodosi: None declared, Andrea Domjan: None declared, Gábor Nagy: None declared, Ibolya Szöllösi: None declared, Luis Lopez Employee of: Retired employee of Corgenix Inc., Eiji Matsuura: None declared, Zoltán Prohászka: None declared, Sándor Szántó: None declared, Zoltán Nagy: None declared, Yehuda Shoenfeld: None declared, Zoltán Szekanecz Grant/research support from: Pfizer, UCB, Consultant of: Sanofi, MSD, Abbvie, Pfizer, Roche, Novertis, Lilly, Gedeon Richter, Amgen, Gabriella Szücs: None declared

SAT0052 THERAPEUTIC STRATEGIES IN DIFFICULT-TO-TREAT RHEUMATOID ARTHRITIS: PRELIMINARY RESULTS OF A SYSTEMATIC LITERATURE REVIEW INFORMING THE 2020 EULAR RECOMMENDATIONS FOR THE MANAGEMENT OF DIFFICULT-TO-TREAT RHEUMATOID ARTHRITIS

Background:

Rheumatoid arthritis (RA) patients treated according to European League Against Rheumatism (EULAR) recommendations failing ≥2 biological or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) with a different mode of action who still have complaints which may be suggestive of active disease may be defined as suffering from ‘difficult-to-treat RA’. Management recommendations for RA focus predominantly on the earlier phases of the disease and specific recommendations for difficult-to-treat RA patients are currently lacking.1

Objectives:

To systematically summarise evidence in the literature on pharmacological and non-pharmacological therapeutic strategies for difficult-to-treat RA patients, informing the 2020 EULAR recommendations for the management of difficult-to-treat RA.

Methods:

A systematic literature review (SLR) was performed: PubMed, Embase and Cochrane databases were searched up to December 2019. Relevant papers were selected and appraised.

Results:

Thirty articles were selected for therapeutic strategies in patients with limited DMARD options due to contraindications, 73 for patients in whom previous b/tsDMARDs were not effective (‘true refractory RA’), and 51 for patients with predominantly non-inflammatory complaints. For patients with limited DMARD options, limited evidence was found on effective DMARD options for patients with concomitant obesity, and on safe DMARD options for patients with concomitant hepatitis B and C. In patients who failed ≥2 bDMARDs, tocilizumab, tofacitinib, baricitinib, upadacitinib and filgotinib were found to be more effective than placebo, but evidence was insufficient to prioritise. In patients who failed ≥1 bDMARD, there was a tendency of non-tumour necrosis factor inhibitor (TNFi) bDMARDs to be more effective than TNFi (Figure 1). Generally, b/tsDMARDs become less effective when patients failed more bDMARDs, this tendency was not clear for upadacitinib and filgotinib (Figure 2). In patients with predominantly non-inflammatory complaints (mainly function, pain and fatigue), exercise, education, psychological and self-management interventions were found to be of additional benefit.

Conclusion:

This SLR underscores the scarcity of evidence on the optimal treatment of difficult-to-treat RA patients. As difficult-to-treat RA is a newly defined disease state, all evidence is to an extent indirect. Several b/tsDMARDs were found to be effective in patients who failed ≥2 bDMARDs and generally effectiveness decreased with a higher number of failed bDMARDs. Additionally, a beneficial effect of non-pharmacological interventions was found on non-inflammatory complaints.

References:

[1] Smolen JSet al. Ann Rheum Dis2020. Epub ahead of print.

Disclosure of Interests:

Nadia M. T. Roodenrijs: None declared, Attila Hamar: None declared, Melinda Kedves: None declared, György Nagy: None declared, Jacob M. van Laar Grant/research support from: MSD, Genentech, Consultant of: MSD, Roche, Pfizer, Eli Lilly, BMS, Désirée van der Heijde Consultant of: AbbVie, Amgen, Astellas, AstraZeneca, BMS, Boehringer Ingelheim, Celgene, Cyxone, Daiichi, Eisai, Eli-Lilly, Galapagos, Gilead Sciences, Inc., Glaxo-Smith-Kline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, UCB Pharma; Director of Imaging Rheumatology BV, Paco Welsing: None declared

1724. Plasmid-free CRISPR-Cas9 System for Genetic Engineering of Rhizopus delemar

Background

Mucormycosis is a serious infection caused by fungi of the order Mucorales. Rhizopus delemar is the most common etiologic agent of mucormycosis. Pathogenesis studies of mucormycosis have been hampered by poor genetic trackability of the organism, owing to rare chromosomal integration events and multinucleated nature of the cells. The clustered regularly interspaced short palindromic repeat (CRISPR)-associated nuclease 9 (Cas9) system has been widely used in genetic manipulation through efficient homologous and non-homologous break points in a variety of organisms including R. delemar. However, plasmid-free CRISPR/Cas9 system has not been previously described in the fungus. Here, we introduce a rapid plasmid-free system for inducing orotidine 5’-phosphate decarboxylase (pyrF) gene mutation in R. delemar.

Methods

Protoplasts of R. delemar 99–880 strain were transformed with 20 nucleotide gRNA targeting the N-terminus of pyrF gene and the Cas9 enzyme. Screening for pyrF auxotrophy was carried out by plating transformed protoplasts on potato dextrose agar (PDA) plates containing 1 mg/mL 5-fluoroorotic acid (5-FOA) and 100 µg/mL uracil. Putative mutant strains were selected for uracil auxotrophy by plating simultaneously on media with or without uracil. pyrF disruption was verified by using PCR and qRT–PCR.

Results

Approximately100 transformants were generated through plating on 5-FOA plates. Only three transformants did not grow on minimal medium lacking uracil, indicating that they were true pyrF null mutants. PCR analysis showed that these three transformants have undergone nucleotide deletion events within the pyrF gene. The lack of pyrF gene expression was further verified by using qRT–PCR relative to wild-type R. delemar 99–880.

Conclusion

Similar to the plasmid-based genome manipulation strategy, the plasmid-free CRISPR/Cas9 system can induce gene editing in R. delemar. This rapid and simple approach adds an additional tool in our conquest to understand pathogenesis of mucormycosis.

Disclosures

All authors: No reported disclosures.

SESCA: Predicting Circular Dichroism Spectra from Protein Molecular Structures

Circular dichroism (CD) spectroscopy is a highly sensitive but low-resolution technique to study the structure of proteins. Combined with molecular modeling or other complementary techniques, CD spectroscopy can provide essential information at higher resolution. To this end, we introduce a new computational method to calculate the electronic circular dichroism spectra of proteins from a structural model or ensemble using the average secondary structure composition and a precalculated set of basis spectra. The method is designed for model validation to estimate the error of a given protein structural model based on the measured CD spectrum. We compared the predictive power of our method to that of existing algorithms, namely, DichroCalc and PDB2CD, and found that it predicts CD spectra more accurately. Our results indicate that the derived basis sets are robust to both experimental errors in the reference spectra and the choice of the secondary structure classification algorithm. For over 80% of the globular reference proteins, our basis sets accurately predict the experimental spectrum solely from their secondary structure composition. For the remaining 20%, correcting for intensity normalization considerably improves the prediction power. Additionally, we show that the predictions for short peptides and an example complex of intrinsically disordered proteins strongly benefit from accounting for side-chain contributions and structural flexibility.

Abdominal Compartment Syndrome After Liver Transplant in Drug-Induced Acute Liver Failure: A Case Report

The incidence of drug-induced acute liver failure (ALF) has been increasing in recent years. Despite the complex intensive treatment, liver transplant should be performed in progressive cases. A systemic inflammatory response syndrome and the burden of surgical intervention promote abdominal compartment syndrome (ACS); observed preoperatively, they are significant negative prognostic factors. THE CASE: We demonstrate a young woman with liver transplant after ALF and a consecutive ACS. We presumed drug toxicity in the background of the rapidly progressive ALF, based on the preoperative hematologic examination and the histology of the removed liver. An ACS has occurred in the postoperative period that must have been resolved with mesh, and later, anatomic segment 2-3 resection had to be performed to further decrease the pressure. The patient left the hospital after 62 days with good graft function. DISCUSSION: A complex intensive care is mandatory in the case of orthotopic liver transplant for ALF. Outcomes are good after orthotopic liver transplant. An ACS might occur after surgery. In these rare cases a delayed abdominal closure or even a liver resection can be the only solution and sometimes an urgent need to resolve the life-threatening problem.

Effect of preoperative injection of superparamagnetic iron oxide particles on rates of sentinel lymph node dissection in women undergoing surgery for ductal carcinoma in situ (SentiNot study)

Background

One-fifth of patients with a preoperative diagnosis of ductal carcinoma in situ (DCIS) have invasive breast cancer (IBC) on definitive histology. Sentinel lymph node dissection (SLND) is performed in almost half of women having surgery for DCIS in Sweden. The aim of the present study was to try to minimize unnecessary SLND by injecting superparamagnetic iron oxide (SPIO) nanoparticles at the time of primary breast surgery, enabling SLND to be performed later, if IBC is found in the primary specimen.

Methods

Women with DCIS at high risk for the presence of invasion undergoing breast conservation, and patients with DCIS undergoing mastectomy were included. The primary outcome was whether this technique could reduce SLND. Secondary outcomes were number of SLNDs avoided, detection rate and procedure-related costs.

Results

This was a preplanned interim analysis of 189 procedures. IBC was found in 47 and a secondary SLND was performed in 41 women. Thus, 78·3 per cent of patients avoided SLND (P &lt; 0·001). At reoperation, SPIO plus blue dye outperformed isotope and blue dye in detection of the sentinel node (40 of 40 versus 26 of 40 women; P &lt; 0·001). Costs were reduced by a mean of 24·5 per cent in women without IBC (€3990 versus 5286; P &lt; 0·001).

Conclusion

Marking the sentinel node with SPIO in women having surgery for DCIS was effective at avoiding unnecessary SLND in this study. Registration number: ISRCTN18430240 (http://www.isrctn.com).

Cross-specificity of protective human antibodies against Klebsiella pneumoniae LPS O-antigen

Humoral immune responses to microbial polysaccharide surface antigens can prevent bacterial infection but are typically strain specific and fail to mediate broad protection against different serotypes. Here we describe a panel of affinity-matured monoclonal human antibodies from peripheral blood immunoglobulin M-positive (IgM⁺) and IgA⁺ memory B cells and clonally related intestinal plasmablasts, directed against the lipopolysaccharide (LPS) O-antigen of Klebsiella pneumoniae, an opportunistic pathogen and major cause of antibiotic-resistant nosocomial infections. The antibodies showed distinct patterns of in vivo cross-specificity and protection against different clinically relevant K. pneumoniae serotypes. However, cross-specificity was not limited to K. pneumoniae, as K. pneumoniae-specific antibodies recognized diverse intestinal microbes and neutralized not only K. pneumoniae LPS but also non-K. pneumoniae LPS. Our data suggest that the recognition of minimal glycan epitopes abundantly expressed on microbial surfaces might serve as an efficient humoral immunological mechanism to control invading pathogens and the large diversity of the human microbiota with a limited set of cross-specific antibodies.

Preventive andTherapeutic Effects of Chlorhexidine Containing Varnish on Candida Biofilm

The aim of the study was to assess the preventive and therapeutic efficacy of a sustained-release varnish (SRV) Cervitec Plus� compared with Corsodyl� mouthwash against Candida albicans, Candida parapsilosis, Candida tropicalis and Candida glabrata on acrylate surfaces. Nystatin as the positive control, and sterile saline solution as the negative control, were used. To examine the preventive efficacy of the agents, Candida biofilms were developed in Sabouraud liquid medium, and mature biofilms were treated with the antifungal. To investigate the preventive efficacy, the agents were applied to the wells of the plates and the biofilms were grown in the treated wells. To determine the metabolic activity of biofilms, the XTT-assay was used. In the case of C. albicans and C. parapsilosis, the most effective therapeutic product was Corsodyl� followed by Cervitec Plus� and Nystatin. The differences were statistically significant when Corsodyl� was compared to Nystatin ( p � 0.05). In relation to C. tropicalis and C. glabrata, Corsodyl� showed the greatest therapeutic efficacy followed by Nystatin and Cervitec Plus�. For both species, the results of Corsodyl� and Cervitec Plus� showed statistically significant difference ( p � 0.05). The most effective preventive product for each examined Candida species was Nystatin, followed by Cervitec Plus� and Corsodyl�. Significant differences were between Nystatin and Corsodyl� (p � 0.05). The preventive and therapeutic efficacy of Cervitec Plus� and Corsodyl�, against the examined Candida species, was detected. Because of the disadvantageous side-effects of Nystatin, Cervitec Plus� can be considered as an alternative preventive agent against Candida species.

Mycoplasma infection followed by time-lapse microscopy

Early detection of mycoplasma infection is crucial for saving precious often irreplaceable data from the tissues of patients. Mycoplasma infections cause diseases in the upper and lower respiratory tracts, urethritis in men resulting in painful dysuria, urgency and urethral discharge. Cough, fever, headache, urethritis may persist for several weeks and convalescence is slow. The symptoms of these diseases are aggravated by the detection of mycoplasma infections, that takes either a long time, besides being expensive or is specific and restricted to only a limited number of contaminant strains. Mycoplasmas are hard to detect visually but could be seen and followed by time-lapse microscopy. Our hypothesis is that one can detect mycoplasma infection irrespective of its origin and type of mycoplasma. Main lines of supporting evidence are provided by the time-lapse microscopy showing dynamic morphological alterations caused by mycoplasmas before changes in human cell cultures become visible. Morphometric measurements of mycoplasma infections revealed four subphases: i) detachment of infected cells, ii) aggregation, iii) biofilm formation and iv) shrinkage of infected cells. The applicability of time-lapse microscopy for the detection of mycoplasma infection was validated by a mycoplasma test Kit. Most important implications related to morphometric parameters include the observation of mycoplasma infected cultures for an extended period of time instead of applying static snap-shot microscopy. A reliable method is offered to estimate the time of mycoplasma exposure that elapsed during the cell growth. This microphotometric approach served a more economical detection of mycoplasma contamination at its early stage of cell growth and spread, irrespective of the origin of contaminated serum, without defining the type of mycoplasma.

Exploring the binding pathways of the 14-3-3ζ protein: Structural and free-energy profiles revealed by Hamiltonian replica exchange molecular dynamics with distancefield distance restraints

The 14-3-3 protein family performs regulatory functions in eukaryotic organisms by binding to a large number of phosphorylated protein partners. Whilst the binding mode of the phosphopeptides within the primary 14-3-3 binding site is well established based on the crystal structures of their complexes, little is known about the binding process itself. We present a computational study of the process by which phosphopeptides bind to the 14-3-3ζ protein. Applying a novel scheme combining Hamiltonian replica exchange molecular dynamics and distancefield restraints allowed us to map and compare the most likely phosphopeptide-binding pathways to the 14-3-3ζ protein. The most important structural changes to the protein and peptides involved in the binding process were identified. In order to bind phosphopeptides to the primary interaction site, the 14-3-3ζ adopted a newly found wide-opened conformation. Based on our findings we additionally propose a secondary interaction site on the inner surface of the 14-3-3ζ dimer, and a direct interference on the binding process by the flexible C-terminal tail. A minimalistic model was designed to allow for the efficient calculation of absolute binding affinities. Binding affinities calculated from the potential of mean force along the binding pathway are in line with the available experimental estimates for two of the studied systems.

Low Efficacy of Antibiotics Against Staphylococcus aureus Airway Colonization in Ventilated Patients

Background

Airway-colonization by Staphylococcus aureus predisposes to the development of ventilator-associated tracheobronchitis (VAT) and ventilator-associated pneumonia (VAP). Despite extensive antibiotic treatment of intensive care unit patients, limited data are available on the efficacy of antibiotics on bacterial airway colonization and/or prevention of infections. Therefore, microbiologic responses to antibiotic treatment were evaluated in ventilated patients.

Methods

Results of semiquantitative analyses of S. aureus burden in serial endotracheal-aspirate (ETA) samples and VAT/VAP diagnosis were correlated to antibiotic treatment. Minimum inhibitory concentrations of relevant antibiotics using serially collected isolates were evaluated.

Results

Forty-eight mechanically ventilated patients who were S. aureus positive by ETA samples and treated with relevant antibiotics for at least 2 consecutive days were included in the study. Vancomycin failed to reduce methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA) burden in the airways. Oxacillin was ineffective for MSSA colonization in approximately 30% of the patients, and responders were typically coadministered additional antibiotics. Despite antibiotic exposure, 15 of the 39 patients (approximately 38%) colonized only by S. aureus and treated with appropriate antibiotic for at least 2 days still progressed to VAP. Importantly, no change in antibiotic susceptibility of S. aureus isolates was observed during treatment. Staphylococcus aureus colonization levels inversely correlated with the presence of normal respiratory flora.

Conclusions

Antibiotic treatment is ineffective in reducing S. aureus colonization in the lower airways and preventing VAT or VAP. Staphylococcus aureus is in competition for colonization with the normal respiratory flora. To improve patient outcomes, alternatives to antibiotics are urgently needed.

A Consensus-Based Set of Measures for Oral Health Care

Increasingly more responsive and accountable health care systems are demanded, which is characterized by transparency and explicit demonstration of competence by health care providers and the systems in which they work. This study aimed to establish measures of oral health for transparent and explicit reporting of routine data to facilitate more patient-centered and prevention-oriented oral health care. To accomplish this, an intermediate objective was to develop a comprehensive list of topics that a range of stakeholders would perceive as valid, important, and relevant for describing oral health and oral health care. A 4-stage approach was used to develop the list of topics: 1) scoping of literature and its appraisal, 2) a meeting of experts, 3) a 2-stage Delphi process (online), and 4) a World Café discussion. The aim was to create consensus through structured conversations via a range of stakeholders (general dental practitioners, patients, insurers, and policy makers) from the Netherlands, Germany, the United Kingdom, Ireland, Hungary, and Denmark. The study was part of the ADVOCATE project, and it resulted in a list of 48 topics grouped into 6 clusters: 1) access to dental care, 2) symptoms and diagnosis, 3) health behaviors, 4) oral treatments, 5) oral prevention, and 6) patient perception. All topics can be measured, as they all have a data source with defined numerators and denominators. This study is the first to establish a comprehensive and multiple-stakeholder consented topic list designed for guiding the implementation of transparent and explicit measurement of routine data of oral health and oral health care. Successful measurement within oral health care systems is essential to facilitate learning from variation in practice and outcomes within and among systems, and it potentiates improvement toward more patient-centered and prevention-oriented oral health care.

Chemically Induced Cell Cycle Arrest in Perfusion Cell Culture

In contrast to most present methods, continuous imaging of live cells would require full automation in each processing step. As an integrated system that would meet all requirements does not exist, we have established a long-term scanning-perfusion platform that: (a) replaces old medium with fresh one, (b) bypasses physical contact with the cell culture during continuous cell growth, (c) provides uninterrupted photomicrography of single cells, and (d) secures near physiological conditions and sterility up to several weeks. The system was validated by synchronizing cells using serum starvation and butyrate-induced cell cycle arrest of HaCaT cells.

In Situ Electron Microscopy of Lactomicroselenium Particles in Probiotic Bacteria

Electron microscopy was used to test whether or not (a) in statu nascendi synthesized, and in situ measured, nanoparticle size does not differ significantly from the size of nanoparticles after their purification; and (b) the generation of selenium is detrimental to the bacterial strains that produce them. Elemental nano-sized selenium produced by probiotic latic acid bacteria was used as a lactomicroselenium (lactomicroSel) inhibitor of cell growth in the presence of lactomicroSel, and was followed by time-lapse microscopy. The size of lactomicroSel produced by probiotic bacteria was measured in situ and after isolation and purification. For these measurements the TESLA BS 540 transmission electron microscope was converted from analog (aTEM) to digital processing (dTEM), and further to remote-access internet electron microscopy (iTEM). Lactobacillus acidophilus produced fewer, but larger, lactomicroSel nanoparticles (200-350 nm) than Lactobacillus casei (L. casei), which generated many, smaller lactomicroSel particles (85-200 nm) and grains as a cloudy, less electrodense material. Streptococcus thermophilus cells generated selenoparticles (60-280 nm) in a suicidic manner. The size determined in situ in lactic acid bacteria was significantly lower than those measured by scanning electron microscopy after the isolation of lactomicroSel particles obtained from lactobacilli (100-500 nm), but higher relative to those isolated from Streptococcus thermopilus (50-100 nm). These differences indicate that smaller lactomicroSel particles could be more toxic to the producing bacteria themselves and discrepancies in size could have implications with respect to the applications of selenium nanoparticles as prebiotics.

Activation of GCN2 kinase by ribosome stalling links translation elongation with translation initiation

Ribosome stalling during translation has recently been shown to cause neurodegeneration, yet the signaling pathways triggered by stalled elongation complexes are unknown. To investigate these pathways we analyzed the brain of C57BL/6J-Gtpbp2^nmf205-/- mice in which neuronal elongation complexes are stalled at AGA codons due to deficiencies in a tRNA^Arg_UCU tRNA and GTPBP2, a mammalian ribosome rescue factor. Increased levels of phosphorylation of eIF2α (Ser51) were detected prior to neurodegeneration in these mice and transcriptome analysis demonstrated activation of ATF4, a key transcription factor in the integrated stress response (ISR) pathway. Genetic experiments showed that this pathway was activated by the eIF2α kinase, GCN2, in an apparent deacylated tRNA-independent fashion. Further we found that the ISR attenuates neurodegeneration in C57BL/6J-Gtpbp2^nmf205-/- mice, underscoring the importance of cellular and stress context on the outcome of activation of this pathway. These results demonstrate the critical interplay between translation elongation and initiation in regulating neuron survival during cellular stress.

DOI:http://dx.doi.org/10.7554/eLife.14295.001

Information stored in DNA is used to make proteins in a two-step process. First, the DNA is copied to make molecules of messenger ribonucleic acid (or messenger RNA for short). Next, machines called ribosomes use the messenger RNAs as templates to assemble chains of amino acids – the building blocks of proteins – in a process called translation. Another type of RNA molecule called transfer RNA carries each amino acid to the ribosomes. If a specific transfer RNA is not available for translation at the right time, the ribosome might stall as it moves along the messenger RNA. At this point, the ribosome needs to be restarted or it will fall off the mRNA without finishing the protein.

In 2014, a group of researchers reported that certain types of brain cells are very sensitive to ribosome stalling, and tend to die if translation does not continue. A protein called GTPBP2 was shown to play an important role in restarting stalled ribosomes in these cells. Here, Ishimura, Nagy et al. – including some of the researchers from the earlier work – investigated the molecular pathways that ribosome stalling triggers in brain cells using mutant mice that lacked the GTPBP2 protein. The experiments show that ribosome stalling activates an enzyme known as GCN2, which was already known to sense other types of malfunctions in cellular processes.

Ishimura, Nagy et al. also show that GCN2 triggers stress responses in the cells by activating a communication system called the ATF4 pathway. This pathway protects the cells from damage, and its absence results in more rapid cell deterioration and death. The next challenges are to understand the exact mechanism by which GCN2 senses stalled ribosomes, and to find out how ribosome stalling causes the death of brain cells.

DOI:http://dx.doi.org/10.7554/eLife.14295.002

Multidimensional Analysis of 16 Glucose Isomers by Ion Mobility Spectrometry

Diastereomeric adducts comprising an enantiomerically pure monosaccharide analyte, a peptide, and/or an amino acid and a divalent metal ion (for 16 different monosaccharide isomers) are generated by electrospray ionization and analyzed by combined ion mobility spectrometry-mass spectrometry (IMS-MS) techniques. Mobility distributions of [l-Ser + M + H](+) (where l-Ser is l-serine and M is a given monosaccharide), [l-Phe-Gly + M + H](+) (where l-Phe-Gly is l-phenylalanine-glycine), and [Mn(II) + (l-Phe-Gly - H) + M](+) complex ions are used to determine collision cross sections (ccs in Å(2)), and groups of cross sections for different clusters are proposed as means of identifying the sugar isomers. Within one type of complex, variations in ccs do not always allow delineation between the 16 glucose isomers, but interestingly, when ccs of three different ions are combined as a spatial vector, enantiomers are partially resolved. As a result of this analysis, l-glucose, d-glucose, l-allose, d-allose, d-gulose, d-galactose, and l-mannose are delineated, and for all eight enantiomeric pairs, d and l entities display different coordinates. In addition, different combinations of amino acids, peptide, and metal ions are surveyed, and the potential for yielding unique coordinates for the generated diastereomeric complexes is assessed.

Radiosurgery for cerebral cavernomas

The role of stereotactic radiosurgery (SRS) in the management of cerebral cavernomas (CCMs) remains controversial. However, during the last decade the increasing knowledge on natural history and numerous publications from SRS centers using modern treatment protocols has been changing the initial resistance of the neurosurgical community. Unfortunately, the quality of publications on CCM SRS remains heterogeneous. Controversies arise from the lack of control groups, the different definition of hemorrhage, heterogeneous patient populations, and poor definition of treatment protocols. The key for proper interpretation of results is the understanding of the natural history of CCMs, which is varied both according to anatomical location and the presence or absence of previous hemorrhage. Hemispheric lesions appear to be more benign with lower annual bleed rate and risk of persisting disability, whereas those found in the thalamus, basal ganglia and brainstem typically have higher rebleed risk resulting in higher cumulative morbidity following subsequent hemorrhages. However, we are still unable at presentation to predict the future behavior of an individual lesion. In the present paper we critically review and analyze the modern SRS literature on CCMs. The expanding number of available data with current treatment protocols strongly supports the initial intuition that SRS is an effective treatment alternative for deep-seated CCMs with multiple hemorrhages reducing pretreatment annual rebleed rates from 32% pre-treatment to 1.5% within 2 years after treatment (N.=197). Moreover, it appears to stabilize lesions with no more than one bleed, and it is also effective for CCMs causing therapy resistant epilepsy especially if applied within 3 years after presentation. In modern SRS series the rate of persisting adverse radiation effects is low, resulting only in mild morbidity even in deep-seated lesions (4.16%, N.=376), and morbidity caused by post-treatment hemorrhages is also low (5.3%, N.=132). Admittedly, there is no high quality evidence to define the relative roles of microsurgery, SRS and wait-and-see policy in the management of detected CCMs at present. However, based on increasing positive experience, we recommend early SRS soon after presentation in neurologically intact or minimally disabled patients harboring deep-seated CCMs, because waiting for the cumulative morbidity of the natural history to justify an otherwise low-risk intervention does not serve the patient well.

Dynamic Reorganization of Vortex Matter into Partially Disordered Lattices

We report structural evidence of dynamic reorganization in vortex matter in clean NbSe(2) by joint small-angle neutron scattering and ac susceptibility measurements. The application of oscillatory forces in a transitional region near the order-disorder transition results in robust bulk vortex lattice configurations with an intermediate degree of disorder. These dynamically originated configurations correlate with intermediate pinning responses previously observed, resolving a long-standing debate regarding the origin of such responses.

Increased levels of anti-heat-shock protein 60 (anti-Hsp60) indicate endothelial dysfunction, atherosclerosis and cardiovascular diseases in patients with mixed connective tissue disease

Heat-shock protein 60 (Hsp60) has been shown to provoke inflammation, and anti-Hsp60 may facilitate the development of atherosclerosis. In this study, we have investigated 30 patients with mixed connective tissue disease (MCTD) and assessed anti-Hsp60 and their relationship to cardiovascular diseases (CVD). Out of 30 patients with MCTD, 15 had CVDs. Anti-Hsp60 antibody was determined by enzyme-linked immunosorbent assay. Since endothelial dysfunction and accelerated atherosclerosis are characteristic to MCTD, a wide array of MCTD-, endothelial dysfunction- and CVD-associated parameters was investigated: serum lipid levels, paraoxonase activity (PON1), rich nuclear ribonucleoprotein U1 (anti-U1RNP), anti-endothelial cell antibodies, anti-cardiolipin and anti-β2-glycoprotein I antibody isotypes (anti-CL and anti-β2GPI), endothelin-1 (ET-1) levels, also intima-media thickness (IMT), a quantitative indicator of atherosclerosis. In MCTD, anti-Hsp60 antibody levels were significantly higher than in healthy individuals (p < 0.02). MCTD patients with CVD had significantly higher levels of anti-Hsp60 compared to MCTD without CVD (p = 0.001). Patients with MCTD had significantly lower high-density lipoprotein cholesterol (p = 0.02) and PON activity (p < 0.001), and significantly increased systolic (p < 0.0002) and diastolic (p < 0.001) blood pressure compared to healthy individuals. Anti-U1RNP levels (p < 0.002) and IMT were higher in patients compared to controls (p = 0.002). The CVD-positive MCTD patients had increased anti-Hsp60 (p < 0.0013), anti-CL IgG (p = 0.0005), ET-1 serum concentration (p < 0.05) and IMT levels (p < 0.001) compared to MCTD patients without CVD. Anti-Hsp60 showed a strong correlation with anti-oxLDL (r = 0.36, p = 0.01) and serum ET-1 (r = 0.62, p < 0.001) and negative correlation with PON activity (r = -0.47, p = 0.01). Anti-Hsp60 indicates endothelial injury, CVD, and can function as a novel atherosclerotic risk factor, also a valuable diagnostic marker in patients with MCTD.