Fragment Discovery by X-ray Crystallographic Screening Targeting the CTP Binding Site of Pseudomonas aeruginosa IspD.

With antimicrobial resistance (AMR) reaching alarming levels, new anti-infectives with unpreceded mechanisms of action are urgently needed. The 2-C-methylerythritol-D-erythritol-4-phosphate (MEP) pathway represents an attractive source of drug targets due to its essential role in numerous pathogenic Gram-negative bacteria and Mycobacterium tuberculosis (Mt), whilst being absent in human cells. Here, we solved the first crystal structure of Pseudomonas aeruginosa (Pa) IspD, the third enzyme in the MEP pathway and present the discovery of a fragment-based compound class identified through crystallographic screening of PaIspD.

Autoreactive B cells remain active despite clinical disease control in rheumatoid arthritis.

Background: Autoimmune diseases (AIDs) are frequently hallmarked by the presence of autoreactive B cell responses which are involved in disease pathogenesis. However, the dynamics of such responses and their relation to clinical disease activity in humans is poorly understood. Rheumatoid arthritis (RA), a prototypic chronic AID, is hallmarked by B cell responses directed against citrullinated proteins.

Antigen-specific Fab profiling achieves molecular-resolution analysis of human autoantibody repertoires in rheumatoid arthritis.

The presence of autoantibodies is a defining feature of many autoimmune diseases. The number of unique autoantibody clones is conceivably limited by immune tolerance mechanisms, but unknown due to limitations of the currently applied technologies. Here, we introduce an autoantigen-specific liquid chromatography-mass spectrometry-based IgG1 Fab profiling approach using the anti-citrullinated protein antibody (ACPA) repertoire in rheumatoid arthritis (RA) as an example.

On the Synthesis and Structure of 'Naked' Ga(I) and In(I) Salts and the Surprising Stability of Simple Ga(I) and In(I) Salts in the Coordinating Solvents Ether and Acetonitrile.

In this work, we present the solid-state structures of solvent-free Ga[pf] and In[pf] salts ([pf]=[Al(OR)]; R=C(CF)), which are very rare examples of salts with truly 'naked' metal cations. Both salts may serve as starting materials for subvalent gallium and indium chemistry with very weakly coordinating ligands providing the freedom of choice for solvents and ligands for the future. On the other hand, we report and rationalize the formation and isolation of [M(OEt)][pf] and [M(MeCN)][pf] (M=Ga, In), underlining the surprising stability of these subvalent group 13 M ions against disproportionation.

Beyond the surface - Autoreactive B cells in human autoimmune diseases.

Background: The generation and persistence of autoreactive B and plasma cells is crucial to the pathogenesis of many human autoimmune diseases. Secreted autoantibodies frequently serve as biomarkers in clinical practice and, in some cases, function as pathogenic effector molecules. Nonetheless, the primary break of B cell tolerance against autoantigens, the triggers that maintain autoreactive B cell memory, and the phenotype that autoreactive B cells adopt during the disease course are poorly understood.

A robust nanoscale RP HPLC-MS approach for sensitive Fc proteoform profiling of IgG allotypes.

The conserved region (Fc) of IgG antibodies dictates the interactions with designated receptors thus defining the immunological effector functions of IgG. Amino acid sequence variations in the Fc, recognized as subclasses and allotypes, as well as post-translational modifications (PTMs) modulate these interactions. Yet, the high similarity of Fc sequences hinders allotype-specific PTM analysis by state-of-the-art bottom-up methods and current subunit approaches lack sensitivity and face co-elution of near-isobaric allotypes.

Structures, Bonding Analyses and Reactivity of a Dicationic Digallene and Diindene Mimicking trans-bent Ditetrylenes.

The reaction of bisdicyclohexylphosphinoethane (dcpe) and the subvalent M sources [M (PhF) ][pf] (M=Ga , In ; [pf] =[Al(OR ) ] ; R =C(CF ) ) yielded the salts [{M(dcpe)} ][pf] , containing the first dicationic, trans-bent digallene and diindene structures reported so far. The non-classical M ⇆M double bonds are surprisingly short and display a ditetrylene-like structure. The bonding situation was extensively analyzed by quantum chemical calculations, QTAIM (Quantum Theory of Atoms in Molecules) and EDA-NOCV (Energy Decomposition Analysis with the combination of Natural Orbitals for Chemical Valence) analyses and is compared to that in the isoelectronic and isostructural, but neutral digermenes and distannenes.

Autoreactive B cells in rheumatoid arthritis include mainly activated CXCR3+ memory B cells and plasmablasts.

Many autoimmune diseases (AIDs) are characterized by the persistence of autoreactive B cell responses, which have been directly implicated in disease pathogenesis. How and why these cells are generated or how they are maintained for years is largely unknown. Rheumatoid arthritis (RA) is among the most common AIDs and is characterized by autoantibodies recognizing proteins with posttranslational modifications (PTMs).

Anti-topoisomerase, but not anti-centromere B cell responses in systemic sclerosis display active, Ig-secreting cells associated with lung fibrosis.

Objectives: Almost all patients with systemic sclerosis (SSc) harbour autoantibodies. Anti-topoisomerase antibodies (ATA) and anti-centromere antibodies (ACA) are most prevalent and associate with distinct clinical phenotypes. B cell responses underlying these phenotypes are ill-defined.

Anti-carbamylated protein antibodies in systemic sclerosis.

Background: To investigate the presence of different isotypes of anti-carbamylated protein (CarP) antibodies in systemic sclerosis (SSc) patients and its association with skin involvement.

Methods: Sera of 194 SSc patients from the Leiden CCISS cohort, fulfilling ACR/EULAR 2013 criteria and a clinical diagnosis of SSc, 83 patients with other connective tissue diseases/Raynaud's Phenomenon, 24 rheumatoid arthritis patients and 98 age and sex-matched healthy controls were tested for the presence of anti-CarP IgG, IgA and IgM, determined by ELISA. Clinical characteristics, that were evaluated in SSc patients, included age, anti-topoisomerase antibodies (ATA), anti-centromere antibodies (ACA) and modified Rodnan Skin Score (mRSS).

Observation of magnetic structural universality and jamming transition with NMR.

Nuclear magnetic resonance (NMR) has been instrumental in deciphering the structure of proteins. Here we show that transverse NMR relaxation, through its time-dependent relaxation rate, is distinctly sensitive to the structure of complex materials or biological tissues at the mesoscopic scale, from micrometers to tens of micrometers. Based on the ideas of universality, we show analytically and numerically that the time-dependent transverse relaxation rate approaches its long-time limit in a power-law fashion, with the dynamical exponent reflecting the universality class of mesoscopic magnetic structure.

Structure-activity relationships of actively FhuE transported rifabutin derivatives with potent activity against Acinetobacter baumannii.

Hospital-acquired infections are on the rise and represent both, a clinical and financial burden. With resistance emerging and an ever-dwindling armamentarium at hand, infections caused by Acinetobacter baumannii are particularly problematic, since these bacteria have a high level of resistance and resilience to traditional and even last-resort antibiotics. The antibiotic rifabutin was recently found to show potent in vitro and in vivo activity against extensively drug resistant A.

The perfluoroadamantoxy aluminate as an ideal weakly coordinating anion? - synthesis and first applications.

Weakly coordinating anions (WCAs) facilitate the stabilization and isolation of highly reactive and almost "naked" cations. Alkoxyaluminate-based WCAs such as [Al(OC(CF))] ([]) are widely used due to their synthetic accessibility and their high stability. However, small cations are still able to coordinate the oxygen atoms of the [] anion or even to abstract an alkoxy ligand.

Papillary Thyroid Microcarcinoma: Insights from a Cohort of 257 Thyroidectomized Patients.

Papillary thyroid microcarcinoma management evolved, and less aggressive strategies are now considered. Questions, however, remain on these tumors' behavior, particularly on developing countries' real ground healthcare scenarios. Our aim is to gather insights on the natural history of papillary thyroid microcarcinoma on patients treated with thyroidectomy in Brazil.

A subset of antibodies targeting citrullinated proteins confers protection from rheumatoid arthritis.

Although elevated levels of anti-citrullinated protein antibodies (ACPAs) are a hallmark of rheumatoid arthritis (RA), the in vivo functions of these antibodies remain unclear. Here, we have expressed monoclonal ACPAs derived from patients with RA, and analyzed their functions in mice, as well as their specificities. None of the ACPAs showed arthritogenicity nor induced pain-associated behavior in mice.

Progression from suspected to definite systemic sclerosis and the role of anti-topoisomerase I antibodies.

Introduction: Early diagnosis of systemic sclerosis (SSc) is important to start therapeutic interventions timely. Important risk factors for progression to SSc are the SSc-specific autoantibodies, of whom anti-centromere antibodies (ACA) and anti-topoisomerase I antibodies (ATA) are the most frequent. ATA is associated with a severe disease course.

How long are Ga⇆Ga double bonds and Ga-Ga single bonds in dicationic gallium dimers?

Syntheses and characterization of two salts [(L)GaGa(L)][] ([] = [Al(OR)]; R = C(CF)) are reported. They include the first dicationic digallene [(L)Ga⇆Ga(L)] (L = CDP = C(PPh)) and a digallane [(L)Ga-Ga(L)] (L = [NacNac]). The CDP-supported digallene dication includes a -bent [L-GaGa-L] bond that is analogous to neutral R-GaGa-R molecules and related to Robinson's famous "Digallyne" [R-GaGa-R].

Identification of Neural Mechanisms in First Single-Sweep Analysis in oVEMPs and Novel Normative Data.

Background: Bone-conducted (BC) VEMPs provide important tools for measuring otolith function. However, two major drawbacks of this method are encountered in clinical practice-small n10 amplitude and averaging technique. In this study, we present the results of a new VEMP setup measuring technique combined with a novel single-sweep analysis.

Impact of Polymer-Assisted Epitaxial Graphene Growth on Various Types of SiC Substrates.

The growth parameters for epitaxial growth of graphene on silicon carbide (SiC) have been the focus of research over the past few years. However, besides the standard growth parameters, the influence of the substrate pretreatment and properties of the underlying SiC wafer are critical parameters for optimizing the quality of monolayer graphene on SiC. In this systematic study, we show how the surface properties and the pretreatment determine the quality of monolayer graphene using polymer-assisted sublimation growth (PASG) on SiC.

Autoreactive B cell responses targeting nuclear antigens in systemic sclerosis: Implications for disease pathogenesis.

A hallmark of disease pathogenesis of systemic sclerosis (SSc) is the presence of autoreactive B cell responses targeting nuclear proteins. Almost all SSc-patients harbour circulating antinuclear autoantibodies of which anti-topoisomerase 1, anti-centromere protein, anti-RNA polymerase III and anti-fibrillarin autoantibodies (ATA, ACA, ARA and AFA, respectively) are the most common and specific for SSc. In clinical practice, autoantibodies serve as diagnostic biomarkers and can aid in the identification of clinical phenotypes of the disease.

Randomized phase I trial of antigen-specific tolerizing immunotherapy with peptide/calcitriol liposomes in ACPA+ rheumatoid arthritis.

BACKGROUNDAntigen-specific regulation of autoimmune disease is a major goal. In seropositive rheumatoid arthritis (RA), T cell help to autoreactive B cells matures the citrullinated (Cit) antigen-specific immune response, generating RA-specific V domain glycosylated anti-Cit protein antibodies (ACPA VDG) before arthritis onset. Low or escalating antigen administration under "sub-immunogenic" conditions favors tolerance.

Absence of Epstein-Barr virus DNA in anti-citrullinated protein antibody-expressing B cells of patients with rheumatoid arthritis.

Objective: Rheumatoid arthritis (RA) is characterized by the presence of disease-specific autoreactive B cell responses, in particular those generating anti-citrullinated protein antibodies (ACPA). For many years, Epstein-Barr virus (EBV) has been implicated in disease pathogenesis, possibly by facilitating the development and persistence of autoreactive B cells. To test this hypothesis, the presence of EBV episomes in ACPA-expressing B cells was analyzed.

Sex-specific risk of anti-topoisomerase antibodies on mortality and disease severity in systemic sclerosis: 10-year analysis of the Leiden CCISS and EUSTAR cohorts.

Background: We aimed to evaluate sex-specific risk of anti-topoisomerase I antibodies (ATA) on mortality, diffuse cutaneous systemic sclerosis, interstitial lung disease, and pulmonary hypertension in two cohorts of people with systemic sclerosis.

Methods: This study was a 10-year analysis of the prospective Leiden Combined Care in Systemic Sclerosis (CCISS) cohort in the Netherlands and the international European Scleroderma Trials and Research (EUSTAR) cohort. We included participants with systemic sclerosis according to the 2013 American College of Rheumatology-European League Against Rheumatism (ACR-EULAR) classification criteria; available autoantibody status; available skin subtyping; at least one available radiographic assessment of interstitial lung disease; and with a known date of disease onset.

Benchmarking computational methods for B-cell receptor reconstruction from single-cell RNA-seq data.

Multiple methods have recently been developed to reconstruct full-length B-cell receptors (BCRs) from single-cell RNA sequencing (scRNA-seq) data. This need emerged from the expansion of scRNA-seq techniques, the increasing interest in antibody-based drug development and the importance of BCR repertoire changes in cancer and autoimmune disease progression. However, a comprehensive assessment of performance-influencing factors such as the sequencing depth, read length or number of somatic hypermutations (SHMs) as well as guidance regarding the choice of methodology is still lacking.

Direct Comparison of Subvalent, Polycationic Group 13 Cluster Compounds: Lessons learned on Isoelectronic DMPE Substituted Gallium and Indium Tetracation Salts.

The tetracationic, univalent cluster compounds [{M(dmpe)} ] (M=Ga, In; dmpe=bis(dimethylphosphino)ethane) were synthesized as their pf salts ([pf] =[Al(OR ) ] ; R =C(CF ) ). The four-membered ring in [{M(dmpe)} ] is slightly puckered for M=Ga and almost square planar for M=In. Yet, although structurally similar, only the gallium cluster is prevalent in solution, while the indium cluster forms temperature dependent equilibria that include even the monomeric cation [In(dmpe)] .