Brain injury in COVID-19 is associated with dysregulated innate and adaptive immune responses.

COVID-19 is associated with neurological complications including stroke, delirium and encephalitis. Furthermore, a post-viral syndrome dominated by neuropsychiatric symptoms is common, and is seemingly unrelated to COVID-19 severity. The true frequency and underlying mechanisms of neurological injury are unknown, but exaggerated host inflammatory responses appear to be a key driver of COVID-19 severity. We investigated the dynamics of, and relationship between, serum markers of brain injury [neurofilament light (NfL), glial fibrillary acidic protein (GFAP) and total tau] and markers of dysregulated host response (autoantibody production and cytokine profiles) in 175 patients admitted with COVID-19 and 45 patients with influenza. During hospitalization, sera from patients with COVID-19 demonstrated elevations of NfL and GFAP in a severity-dependent manner, with evidence of ongoing active brain injury at follow-up 4 months later. These biomarkers were associated with elevations of pro-inflammatory cytokines and the presence of autoantibodies to a large number of different antigens. Autoantibodies were commonly seen against lung surfactant proteins but also brain proteins such as myelin associated glycoprotein. Commensurate findings were seen in the influenza cohort. A distinct process characterized by elevation of serum total tau was seen in patients at follow-up, which appeared to be independent of initial disease severity and was not associated with dysregulated immune responses unlike NfL and GFAP. These results demonstrate that brain injury is a common consequence of both COVID-19 and influenza, and is therefore likely to be a feature of severe viral infection more broadly. The brain injury occurs in the context of dysregulation of both innate and adaptive immune responses, with no single pathogenic mechanism clearly responsible.

Argonaute Autoantibodies as Biomarkers in Autoimmune Neurologic Diseases.

OBJECTIVE: To identify and characterize autoantibodies (Abs) as novel biomarkers for an autoimmune context in patients with central and peripheral neurologic diseases. METHODS: Two distinct approaches (immunoprecipitation/mass spectrometry-based proteomics and protein microarrays) and patients' sera and CSF were used. The specificity of the identified target was confirmed by cell-based assay (CBA) in 856 control samples. RESULTS: Using the 2 methods as well as sera and CSF of patients with central and peripheral neurologic involvement, we identified Abs against the family of Argonaute proteins (mainly AGO1 and AGO2), which were already reported in systemic autoimmunity. AGO-Abs were mostly of immunoglobulin G 1 subclass and conformation dependent. Using CBA, AGO-Abs were detected in 21 patients with a high suspicion of autoimmune neurologic diseases (71.4% were women; median age 57 years) and only in 4/856 (0.5%) controls analyzed by CBA (1 diagnosed with small-cell lung cancer and the other 3 with Sjögren syndrome). Among the 21 neurologic patients identified, the main clinical presentations were sensory neuronopathy (8/21, 38.1%) and limbic encephalitis (6/21, 28.6%). Fourteen patients (66.7%) had autoimmune comorbidities and/or co-occurring Abs, whereas AGO-Abs were the only autoimmune biomarker for the remaining 7/21 (33.3%). Thirteen (61.9%) patients were treated with immunotherapy; 8/13 (61.5%) improved, and 3/13 (23.1%) remained stable, suggesting an efficacy of these treatments. CONCLUSIONS: AGO-Abs might be potential biomarkers of autoimmunity in patients with central and peripheral nonparaneoplastic neurologic diseases. In 7 patients, AGO-Abs were the only biomarkers; thus, their identification may be useful to suspect the autoimmune character of the neurologic disorder. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that AGO-Abs are more frequent in patients with autoimmune neurologic diseases than controls.

The Antibody Society's antibody validation webinar series.

In the wake of the reproducibility crisis and numerous discussions on how commercially available antibodies as research tool contribute to it, The Antibody Society developed a series of 10 webinars to address the issues involved. The webinars were delivered by speakers with both academic and commercial backgrounds. This report highlights the problems, and offers solutions to help the scientific community appropriately identify the right antibodies and to validate them for their research and development projects. Despite the various solutions proposed here, they must be applied on a case-by-case basis. Each antibody must be verified based on the content of the product sheet, and subsequently through experimentation to confirm integrity, specificity and selectivity. Verification needs to focus on the precise application and tissue/cell type for which the antibody will be used, and all verification data must be reported openly. The various approaches discussed here all have caveats, so a combination of solutions must be considered.

Antibody validation: a view from the mountains.

Validation of antibodies and other protein binders is a subject of pressing concern for the research community and one which is uppermost in the minds of all who use antibodies as research and diagnostic reagents. Assessing an antibody's fitness for purpose includes accurate ascertainment of its target specificity and suitability for the envisaged task. Moreover, standardised procedures are essential to guarantee sample quality in testing procedures. The problem of defining precise standards for antibody validation has engendered much debate in recent publications and meetings, but gradually a consensus is emerging. At the 8th Alpbach Affinity Proteomics workshop (March 2017), a panel of leaders in the antibody field discussed suggestions which could bring this complex but essential issue a step nearer to a resolution. 'Alpbach recommendations' for best practice include tailoring binder validation processes according to the intended applications and promoting greater transparency in publications and in the information available from commercial antibody developers/providers. A single approach will not fit all applications and end users must ensure that the reported validation holds for their specific requirements, highlighting the need for adequate training in the fundamentals of antibody characterisation and validation across the user community.

Affinity Proteomics in the mountains: Alpbach 2015.

The 2015 Alpbach Workshop on Affinity Proteomics, organised by the EU AFFINOMICS consortium, was the 7th workshop in this series. As in previous years, the focus of the event was the current state of affinity methods for proteome analysis, including complementarity with mass spectrometry, progress in recombinant binder production methods, alternatives to classical antibodies as affinity reagents, analysis of proteome targets, industry focus on biomarkers, and diagnostic and clinical applications. The combination of excellent science with Austrian mountain scenery and winter sports engender an atmosphere that makes this series of workshops exceptional. The articles in this Special Issue represent a cross-section of the presentations at the 2015 meeting.

The Biobanking Analysis Resource Catalogue (BARCdb): a new research tool for the analysis of biobank samples.

We report the development of a new database of technology services and products for analysis of biobank samples in biomedical research. BARCdb, the Biobanking Analysis Resource Catalogue, is a freely available web resource, listing expertise and molecular resource capabilities of research centres and biotechnology companies. The database is designed for researchers who require information on how to make best use of valuable biospecimens from biobanks and other sample collections, focusing on the choice of analytical techniques and the demands they make on the type of samples, pre-analytical sample preparation and amounts needed. BARCdb has been developed as part of the Swedish biobanking infrastructure (BBMRI.se), but now welcomes submissions from service providers throughout Europe. BARCdb can help match resource providers with potential users, stimulating transnational collaborations and ensuring compatibility of results from different labs. It can promote a more optimal use of European resources in general, both with respect to standard and more experimental technologies, as well as for valuable biobank samples. This article describes how information on service and reagent providers of relevant technologies is made available on BARCdb, and how this resource may contribute to strengthening biomedical research in academia and in the biotechnology and pharmaceutical industries.

Development of proteome-wide binding reagents for research and diagnostics.

Alongside MS, antibodies and other specific protein-binding molecules have a special place in proteomics as affinity reagents in a toolbox of applications for determining protein location, quantitative distribution and function (affinity proteomics). The realisation that the range of research antibodies available, while apparently vast is nevertheless still very incomplete and frequently of uncertain quality, has stimulated projects with an objective of raising comprehensive, proteome-wide sets of protein binders. With progress in automation and throughput, a remarkable number of recent publications refer to the practical possibility of selecting binders to every protein encoded in the genome. Here we review the requirements of a pipeline of production of protein binders for the human proteome, including target prioritisation, antigen design, 'next generation' methods, databases and the approaches taken by ongoing projects in Europe and the USA. While the task of generating affinity reagents for all human proteins is complex and demanding, the benefits of well-characterised and quality-controlled pan-proteome binder resources for biomedical research, industry and life sciences in general would be enormous and justify the effort. Given the technical, personnel and financial resources needed to fulfil this aim, expansion of current efforts may best be addressed through large-scale international collaboration.

Fruits of the ESF Research Networking Programme in Functional Genomics.

Foreword to the special issue of New Biotechnology comprising review articles by former steering committee members to mark the end of the European Science Foundation Research Networking Programme in Functional Genomics.

Optimised 'on demand' protein arraying from DNA by cell free expression with the 'DNA to Protein Array' (DAPA) technology.

We have previously described a protein arraying process based on cell free expression from DNA template arrays (DNA Array to Protein Array, DAPA). Here, we have investigated the influence of different array support coatings (Ni-NTA, Epoxy, 3D-Epoxy and Polyethylene glycol methacrylate (PEGMA)). Their optimal combination yields an increased amount of detected protein and an optimised spot morphology on the resulting protein array compared to the previously published protocol. The specificity of protein capture was improved using a tag-specific capture antibody on a protein repellent surface coating. The conditions for protein expression were optimised to yield the maximum amount of protein or the best detection results using specific monoclonal antibodies or a scaffold binder against the expressed targets. The optimised DAPA system was able to increase by threefold the expression of a representative model protein while conserving recognition by a specific antibody. The amount of expressed protein in DAPA was comparable to those of classically spotted protein arrays. Reaction conditions can be tailored to suit the application of interest. BIOLOGICAL SIGNIFICANCE: DAPA represents a cost effective, easy and convenient way of producing protein arrays on demand. The reported work is expected to facilitate the application of DAPA for personalized medicine and screening purposes.

Workshop on laboratory protocol standards for the Molecular Methods Database.

Management of data to produce scientific knowledge is a key challenge for biological research in the 21st century. Emerging high-throughput technologies allow life science researchers to produce big data at speeds and in amounts that were unthinkable just a few years ago. This places high demands on all aspects of the workflow: from data capture (including the experimental constraints of the experiment), analysis and preservation, to peer-reviewed publication of results. Failure to recognise the issues at each level can lead to serious conflicts and mistakes; research may then be compromised as a result of the publication of non-coherent protocols, or the misinterpretation of published data. In this report, we present the results from a workshop that was organised to create an ontological data-modelling framework for Laboratory Protocol Standards for the Molecular Methods Database (MolMeth). The workshop provided a set of short- and long-term goals for the MolMeth database, the most important being the decision to use the established EXACT description of biomedical ontologies as a starting point.

Affinity proteomics: the role of specific binding reagents in human proteome analysis.

Affinity proteomics is the field of proteome analysis based on the use of antibodies and other binding reagents as protein-specific detection probes. In this review, the particular strengths of affinity methods for determination of protein localization, functional characterization, biomarker discovery and intracellular applications, and their resulting impact in basic and clinical research are highlighted. An additional focus is on the requirements for systematic binder generation and current large-scale binder projects, including bioinformatic frameworks for epitope selection and for documentation of available binding reagents and their performance. In addition to current affinity proteomics methods and applications, including arrays of proteins, binders, lysates and tissues, approaches coupling mass spectrometry-based proteomics and affinity proteomics are reviewed.

European and international collaboration in affinity proteomics.

In affinity proteomics, specific protein-binding molecules (a.k.a. binders), principally antibodies, are applied as reagents in proteome analysis. In recent years, advances in binder technologies have created the potential for an unprecedented view on protein expression and distribution patterns in plasma, cells and tissues and increasingly on protein function. Particular strengths of affinity proteomics methods include detecting proteins in their natural environments of cell or tissue, high sensitivity and selectivity for detection of low abundance proteins and exploiting binding actions such as functional interference in living cells. To maximise the use and impact of affinity reagents, it will be essential to create comprehensive, standardised binder collections. With this in mind, the EU FP7 programme AFFINOMICS (http://www.affinomics.org), together with the preceding EU programmes ProteomeBinders and AffinityProteome, aims to extend affinity proteomics research by generating a large-scale resource of validated protein-binding molecules for characterisation of the human proteome. Activity is directed at producing binders to about 1000 protein targets, primarily in signal transduction and cancer, by establishing a high throughput, coordinated production pipeline. An important aspect of AFFINOMICS is the development of highly efficient recombinant selection methods, based on phage, cell and ribosome display, capable of producing high quality binders at greater throughput and lower cost than hitherto. The programme also involves development of innovative and sensitive technologies for specific detection of target proteins and their interactions, and deployment of binders in proteomics studies of clinical relevance. The need for such binder generation programmes is now recognised internationally, with parallel initiatives in the USA for cancer (NCI) and transcription factors (NIH) and within the Human Proteome Organisation (HUPO). The papers in this volume of New Biotechnology are all contributed by participants at the 5th ESF Workshop on Affinity Proteomics organised by the AFFINOMICS consortium and held in Alpbach, Austria, in March 2011.

Eukaryotic ribosome display with in situ DNA recovery.

Ribosome display is a cell-free display technology for in vitro selection and optimisation of proteins from large diversified libraries. It operates through the formation of stable protein-ribosome-mRNA (PRM) complexes and selection of ligand-binding proteins, followed by DNA recovery from the selected genetic information. Both prokaryotic and eukaryotic ribosome display systems have been developed. In this chapter, we describe the eukaryotic rabbit reticulocyte method in which a distinct in situ single-primer RT-PCR procedure is used to recover DNA from the selected PRM complexes without the need for prior disruption of the ribosome.

Producing protein microarrays from DNA microarrays.

The development of protein microarrays makes possible interaction-based protein assays in miniaturised, multiplexed formats. A major requirement determining their uptake and use is the availability and stability of purified, functional proteins for immobilisation. With conventional methods, involving individual expression and purification of recombinant proteins, the cost of commercial high-content protein arrays is often found to be prohibitively high. Moreover, due to the need for specialised microarray production equipment, custom-made protein arrays containing more focussed sets of proteins of interest are also in little use. In the DNA array to protein array technology described herein, repeated economical printing of protein microarrays from a reusable template DNA microarray is performed on demand by cell-free -protein synthesis. Once the template DNA microarray has been obtained, protein microarrays are made using purely macro-handling procedures, making protein arraying accessible without sophisticated microarraying apparatus.

Cell free expression put on the spot: advances in repeatable protein arraying from DNA (DAPA).

We have previously described the 'DNA array to protein array' (DAPA) method for microarraying of proteins expressed by cell-free systems in situ on the array surface. In this technique, a DNA array on one slide acts as the template for generating a protein array on a second slide, mediated by a cell free lysate between the two juxtaposed slides. Here we explore the feature of the repeatability of the technology, in which the same DNA array is reused several times, and use the method to generate a microarray of 116 diverse proteins. The capabilities of DAPA technology in comparison with other protein array methods are discussed.

"4D Biology for health and disease" workshop report.

The "4D Biology Workshop for Health and Disease", held on 16-17th of March 2010 in Brussels, aimed at finding the best organising principles for large-scale proteomics, interactomics and structural genomics/biology initiatives, and setting the vision for future high-throughput research and large-scale data gathering in biological and medical science. Major conclusions of the workshop include the following. (i) Development of new technologies and approaches to data analysis is crucial. Biophysical methods should be developed that span a broad range of time/spatial resolution and characterise structures and kinetics of interactions. Mathematics, physics, computational and engineering tools need to be used more in biology and new tools need to be developed. (ii) Database efforts need to focus on improved definitions of ontologies and standards so that system-scale data and associated metadata can be understood and shared efficiently. (iii) Research infrastructures should play a key role in fostering multidisciplinary research, maximising knowledge exchange between disciplines and facilitating access to diverse technologies. (iv) Understanding disease on a molecular level is crucial. System approaches may represent a new paradigm in the search for biomarkers and new targets in human disease. (v) Appropriate education and training should be provided to help efficient exchange of knowledge between theoreticians, experimental biologists and clinicians. These conclusions provide a strong basis for creating major possibilities in advancing research and clinical applications towards personalised medicine.

Protein microarrays printed from DNA microarrays.

Protein arrays are miniaturised and highly parallelised formats of interaction-based functional protein assays. Major bottlenecks in protein microarraying are the limited availability and high cost of purified, functional proteins for immobilisation and the limited stability of immobilised proteins in their functional state. In contrast, protein-coding DNA is readily available by PCR, and DNA arrays can be stored over prolonged times without deterioration. This chapter presents a method for the rapid and economical "printing" of replicate protein microarrays directly from a single DNA array template using cell-free protein synthesis, termed "DNA array to protein array," DAPA. The procedure is a truly enabling technology, making customised protein microarrays affordable for laboratories with no access to routine microarray spotting. The experimental effort involved for the printing of a protein array from the template DNA array is comparable to the assembly of a Western blot.