A new T-antigen negative HEK293 cell line with improved AAV productivity.

Viral vectors for gene therapy, such as recombinant adeno-associated viruses, are produced in human embryonic kidney (HEK) 293 cells. However, the presence of the SV40 T-antigen-encoding CDS SV40GP6 and SV40GP7 in the HEK293T genome raises safety issues when these cells are used in manufacturing for clinical purposes. We developed a new T-antigen-negative HEK cell line from ExcellGene's proprietary HEKExpress,® using the CRISPR-Cas9 strategy. We obtained a high number of clonally-derived cell populations and all of them were demonstrated T-antigen negative. Stability study and AAV production evaluation showed that the deletion of the T-antigen-encoding locus did not impact neither cell growth nor viability nor productivity. The resulting CMC-compliant cell line, named HEKzeroT,® is able to produce high AAV titers, from small to large scale.

Failure and multiple failure for disease modifying antirheumatic drugs in rheumatoid arthritis: Real-life evidence from a tertiary referral center in Italy.

BACKGROUND: Rheumatoid Arthritis (RA) is a chronic inflammatory disease with a heterogeneous treatments' clinical response. Goals of treatment are remission and low disease activity, which are not achieved in all patients despite the introduction of early treatment and the treat to target strategy. OBJECTIVE: To investigate the causes of disease-modifying antirheumatic drugs (DMARDs) discontinuation and treatment failure and multiple failure for inefficacy, and to identify possible failure predictors' according to RA patient characteristics in a real-world setting. METHODS: 718 RA patients were retrospectively evaluated. Conventional synthetic (cs) and biologic (b)DMARDs treatments line/s, effectiveness, and reasons of discontinuations were evaluated. Patients failing to at least two csDMARDs or bDMARDs' drug for inefficacy were defined "csDMARDs multifailure" and "bDMARDs multifailure", respectively. Discontinuation of at least two cs- and bDMARDs was termed "global multifailure". RESULTS: In total, 1422 csDMARDs and 714 bDMARDs treatment were analysed. Causes of csDMARDs discontinuation were intolerance (21.8%), inefficacy (20.2%), acute adverse reactions (5.3%) and severe infections (0.6%) while csDMARDs multifailure for inefficacy was observed in 5.7% of cases. Reasons of bDMARDs withdrawal were inefficacy (29%), intolerance (10.0%), acute adverse reaction (6.3%) and severe infections (1.5%). Altogether, 8.4% of patients were bDMARDs multifailure for inefficacy while 16.6% were global multifailure. Longstanding disease (≥ 12 months) and smoke habit, resulted as positive predictor of csDMARDs failure (OR 2.6 and OR 2.7, respectively). Thyreopathy was associated with both csDMARDs failure and global multifailure (OR 2.4 and OR 1.8, respectively). Higher prevalence of failure to at least one bDMARDs and global multifailure was detected in female than male (OR 2.3 and OR 2, respectively). CONCLUSIONS: Different causes of drug discontinuation were observed on DMARDs treatments. Demographic and clinical features were identified as possible predictors of both cs- and bDMARDs treatment failure and multiple failure, underlining the need of a more personalized therapeutic approach to achieve treatment targets.

Assessment of microvascular involvement in lupus nephritis patients by retinal OCT-angiography and kidney biopsies.

OBJECTIVES: Ocular and renal microvascular damage in lupus nephritis (LN) share similar physiopathological pathways that have investigated using traditional fundus examination and high-resolution colour electroretinography. Optical coherence tomography angiography (OCTA) is a recent, non-invasive technique for imaging the microvasculature of retina and choroid. Aim of the study was to investigate through OCTA analysis the relationship between retinal microvascular alterations and renal functional and histologic features. METHODS: Systemic lupus erythematosus (SLE) patients with LN, SLE without renal involvement and healthy controls were recruited and accomplished an ophthalmological evaluation, including OCTA. SLE-LN patients underwent a rheumatological evaluation, including disease-related clinical and laboratory features collection and kidney biopsy examination. RESULTS: This cross-sectional study enrolled forty-six eyes of 23 LN patients, thirty-two eyes of 16 SLE patients and forty-two eyes of 21 controls. Thirteen SLE-LN patients (56.5%) displayed lupus retinopathy, 10 at moderate (77%) and 3 at severe stage (23%) by fundus oculi examination. Analysis of OCTA data showed with high/moderate accuracy a reduction of retinal capillary vessel density in both SLE and SLE-LN patients compared to controls in superficial and deep plexi. A reduction in fovea thickness and an increase in foveal avascular zone were also detected. OCTA data of LN patients correlated with LN duration, disease activity, kidney function and the presence of LN-vascular lesions at kidney biopsy. CONCLUSIONS: Our results suggest the role of OCTA in early detection of systemic vascular involvement in SLE-LN patients and related kidney functional-histological impairment.

Long-term effectiveness and drug survival of golimumab in patients affected by psoriatic arthritis with cutaneous involvement.

OBJECTIVES: To determine the effectiveness of golimumab (GLM) in improving joint, periarticular structures and cutaneous manifestations in patients with moderate to severe psoriatic arthritis (PsA) with cutaneous psoriasis in different real-life clinical settings and 48-month drug survival. METHODS: Clinical and laboratory records were collected from PsA patients treated with GLM at baseline (T0) and after 6, 12, 24, 36, and 48 months of treatment. Comparisons were performed using a paired t-test or Wilcoxon test. Drug survival rates were analyzed using Kaplan-Meier estimates. p value < 0.05 was considered statistically significant. RESULTS: Data from 105 patients were collected. PsO occurred in 80% of patients and enthesitis in 78%, peripheral and axial arthritis in 63.8% and 35.3%, respectively, while erosions in 36.2%. The main comorbidities were cardiovascular diseases (31.4%) and metabolic syndrome (MetS) (19%). A statistically significant improvement in articular and cutaneous psoriasis was registered at T48 of GLM-therapy in clinical (DAPSA p < 0.0001; PASI p < 0.01; BASDAI p < 0.0001) and laboratory (CRP < 0.05) indexes. Gender (p = 0.652), BMI (p = 0.655), smoking habit (p = 0.466), and line of treatment (p = 0.208) did not affect treatment efficacy nor persistence. At T48, 42% of patients discontinued GLM: the most frequent reason was an insufficient response or loss of efficacy (28.6%). CONCLUSION: A 48-month GLM high drug persistence of PsA patients was observed in real-life, in patients presenting high disease activity, elevated prevalence of comorbidities, and more than one line of treatment at baseline. Patients' characteristics as gender, smoke, BMI, different lines of treatment, and concomitant methotrexate treatment affected treatment persistence, making GLM effective and safe in moderate-severe PsA in a long-term real-life setting. Key Points • Golimumab was effective in psoriatic arthritis, including both musculoskeletal and cutaneous manifestations. • Golimumab effectiveness and drug survival were not affected by comorbidities and patient-related characteristics. • The 4-year drug survival curves confirm the efficacy and safety of golimumab in psoriatic arthritis patients in a real-life setting.

Palmitoylated acyl protein thioesterase APT2 deforms membranes to extract substrate acyl chains.

Many biochemical reactions require controlled recruitment of proteins to membranes. This is largely regulated by posttranslational modifications. A frequent one is S-acylation, which consists of the addition of acyl chains and can be reversed by poorly understood acyl protein thioesterases (APTs). Using a panel of computational and experimental approaches, we dissect the mode of action of the major cellular thioesterase APT2 (LYPLA2). We show that soluble APT2 is vulnerable to proteasomal degradation, from which membrane binding protects it. Interaction with membranes requires three consecutive steps: electrostatic attraction, insertion of a hydrophobic loop and S-acylation by the palmitoyltransferases ZDHHC3 or ZDHHC7. Once bound, APT2 is predicted to deform the lipid bilayer to extract the acyl chain bound to its substrate and capture it in a hydrophobic pocket to allow hydrolysis. This molecular understanding of APT2 paves the way to understand the dynamics of APT2-mediated deacylation of substrates throughout the endomembrane system.

The burden of depressive disorders in musculoskeletal diseases: is there an association between mood and inflammation?

IMPORTANCE: Evidence emerged concerning how inflammatory arthritis and mood disorders can often occur in the same patient and show a similar clinical pattern. An overview of the rheumatological and psychiatric aspects of these diseases can certainly be useful for the improvement of patients' clinical and therapeutic management. OBJECTIVE: The aim of this narrative review was to summarize existing literature about common pathogenetic and clinical aspects as a means of improving management and therapeutic approach in patients affected by rheumatoid arthritis, psoriatic arthritis and spondyloarthritis. Outcomes such as disease activity indexes and patient reported outcomes (PROs) were considered. FINDINGS: Common pathogenetic pathways emerged between inflammatory arthritis and mood disorders. Pro-inflammatory mechanisms, such as TNFα, IL-6, IL-17 and oxidative stress factors as well as neurotransmitter alterations at the level of CNS and blood-brain barrier (BBB) cells are involved. The activation of these common pathogenetic pathways is, also, affected by the same triggers, such as smoking, stress, lifestyle, and evidence has emerged concerning the possibility of the clinical efficacy of using the same therapeutic approaches. CONCLUSIONS: The main causes of the variability in clinical studies outcomes are the rheumatological diseases considered, the prevalence of depression in the general population and in patients with rheumatological diseases and the type of depressive symptom examined. Patients affected by inflammatory arthritis can present symptoms and signs in common with mood disorders, leading to possible clinical overlap. There are still few studies analyzing this concept: they are extremely heterogeneous, both in the characteristics of the population taken into consideration and in the methods used for the definition of depressive disorder, but the suggestions of the data obtained so far are promising and deserve to be pursued.

CLoNe: automated clustering based on local density neighborhoods for application to biomolecular structural ensembles.

MOTIVATION: Proteins are intrinsically dynamic entities. Flexibility sampling methods, such as molecular dynamics or those arising from integrative modeling strategies, are now commonplace and enable the study of molecular conformational landscapes in many contexts. Resulting structural ensembles increase in size as technological and algorithmic advancements take place, making their analysis increasingly demanding. In this regard, cluster analysis remains a go-to approach for their classification. However, many state-of-the-art algorithms are restricted to specific cluster properties. Combined with tedious parameter fine-tuning, cluster analysis of protein structural ensembles suffers from the lack of a generally applicable and easy to use clustering scheme. RESULTS: We present CLoNe, an original Python-based clustering scheme that builds on the Density Peaks algorithm of Rodriguez and Laio. CLoNe relies on a probabilistic analysis of local density distributions derived from nearest neighbors to find relevant clusters regardless of cluster shape, size, distribution and amount. We show its capabilities on many toy datasets with properties otherwise dividing state-of-the-art approaches and improves on the original algorithm in key aspects. Applied to structural ensembles, CLoNe was able to extract meaningful conformations from membrane binding events and ligand-binding pocket opening as well as identify dominant dimerization motifs or inter-domain organization. CLoNe additionally saves clusters as individual trajectories for further analysis and provides scripts for automated use with molecular visualization software. AVAILABILITY AND IMPLEMENTATION: www.epfl.ch/labs/lbm/resources, github.com/LBM-EPFL/CLoNe. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Tackling the autoimmune side in Spondyloarthritis: A systematic review.

Spondyloarthritis (SpA) are a heterogeneous group of inflammatory chronic diseases characterized by sharing common pathogenic, clinical and radiologic features. The aim of this review is to support clinicians in understanding and managing this complex disease, from pathogenesis to therapeutic targets, through a systematic review of the current literature in accordance with PRISMA guidelines and checklist. HLA-B27 has been found to be associated with axial involvement either in SA and in PsA patients: it might be involved through presentation of an "arthritogenic peptide" to autoreactive CD8+ T cells or might accumulate in misfolded form and induce production pro-inflammatory cytokines by binding to several innate immune receptors. This genetic background in combination with mechanical stress leads to the activation of both innate and acquired immune responses as well as a possible role of autoimmunity in SpA pathogenesis. The release of IL-23 and IL-17 is relevant for their systemic and local effect on bone, inducing the activation of osteoclasts. Thus, the regulatory role of IL-17 on fibroblasts, osteoblasts and chondrocytes has an impact in both synovial inflammation and joint destruction. Innovative therapies targeting IL-12/23 and IL-17 and the use of small targeted synthetic molecules, as JAK-inhibitors, proved to be effective in SpA patients representing an alternative strategy to TNF-inhibitors.

One-year effectiveness, retention rate, and safety of secukinumab in ankylosing spondylitis and psoriatic arthritis: a real-life multicenter study.

BACKGROUND: Secukinumab (SEC) is effective for ankylosing spondylitis (AS) and psoriatic arthritis (PsA) in randomized trials, but real-life data are lacking. RESEARCH DESIGN AND METHODS: Real-life, prospective observational study on 169 consecutive outpatients at baseline (T0) and at 6 (T6) and 12 months (T12) after starting SEC (39 AS, 23%; 130 PsA, 77%). RESULTS: Significant improvement was seen at T6 and T12 for all clinical variables, including TJC, SJC, ESR, CRP, DAPSA, ASDAS-CRP, and BASDAI, as well as in patient-reported outcomes like VAS-pain. By multivariable regression analysis, in AS patients high BASDAI at T0 correlated with diagnostic delay (R2 = 0.4; p = 0.009) and peripheral joint involvement (R2 = 0.4; p = 0.04). During follow-up, reduction of BASDAI positively correlated with high ESR (R2 = 0.65; p = 0.04). ASDAS-CRP at T0 positively correlated with high ESR (R2 = 0.34; p = 0.004). Reduction of ASDAS-CRP from T0 to T6 correlated with current smoking status (R2 = 0.42; p = 0.003). In PsA patients, reduction of DAPSA score from T0 to T12 is negatively correlated with the presence of metabolic syndrome (R2 = 0.41; p = 0.0025). SEC was well tolerated; 10 patients discontinued treatment for non-severe adverse events. CONCLUSIONS: Secukinumab is effective and safe in patients with AS and PsA in a real-life setting.

Retention rates and identification of factors associated with anti-TNFα, anti-IL17, and anti-IL12/23R agents discontinuation in psoriatic arthritis patients: results from a real-world clinical setting.

INTRODUCTION: Biologic disease-modifying antirheumatic drugs (bDMARDs) play a pivotal role in the treatment of psoriatic arthritis (PsA). Despite this, their discontinuation due to inefficacy or adverse events is often observed. The aims of this study are to describe retention rates and treatment trends of anti-TNFα, anti-IL17, and anti-IL12/23R agents in patients with PsA and to identify factors associated with bDMARDs discontinuation in a real-world clinical setting. METHODS: A retrospective cohort study based on the analysis of the three Italian prescription cohorts of patients with PsA has been performed. Survival analysis was performed using Kaplan-Meier curves and Cox proportional-hazards model. RESULTS: During the follow up, which lasted 25.5 (12-60) months, 68 patients discontinued a bDMARD: 13 for primary failure, 12 for secondary failure, 15 for adverse events, 5 for remission, 12 because of lost at follow-up, and 11 for other causes. Cox proportional-hazards demonstrated that a shorter disease duration (HR 0.994991, 95% CI 0.9910336-0.9989647, p = 0.014) and first-line bDMARD (HR 0.5090986, 95% CI 0.3073519-0.8432722, p = 0.009) have a protective role on bDMARD retention rate, while the multivariable analysis failed in demonstrating an independent protective role of male sex on drug retention rate (p = 0.083). No significant differences in retention rate have been found regarding biologic drugs, combination therapy or monotherapy, and class of bDMARD (anti-TNFα or anti-pIL12/23R and anti-IL-17). CONCLUSIONS: This study shows that a shorter disease duration and treatment with a first-line bDMARD are predictors of bDMARDs retention rate, further highlighting the importance of early diagnosis of PsA. Key Points • No significant difference in retention among patients treated with anti-IL17A, anti-IL12/23R, and anti-TNFα agents has been demonstrated. • A shorter disease duration and first-line bDMARD treatment are associated with persistence in biologic treatment.

KAP1 is an antiparallel dimer with a functional asymmetry.

KAP1 (KRAB domain-associated protein 1) plays a fundamental role in regulating gene expression in mammalian cells by recruiting different transcription factors and altering the chromatin state. In doing so, KAP1 acts both as a platform for macromolecular interactions and as an E3 small ubiquitin modifier ligase. This work sheds light on the overall organization of the full-length protein combining solution scattering data, integrative modeling, and single-molecule experiments. We show that KAP1 is an elongated antiparallel dimer with an asymmetry at the C-terminal domains. This conformation is consistent with the finding that the Really Interesting New Gene (RING) domain contributes to KAP1 auto-SUMOylation. Importantly, this intrinsic asymmetry has key functional implications for the KAP1 network of interactions, as the heterochromatin protein 1 (HP1) occupies only one of the two putative HP1 binding sites on the KAP1 dimer, resulting in an unexpected stoichiometry, even in the context of chromatin fibers.

An update on pathogenesis of psoriatic arthritis and potential therapeutic targets.

Introduction: Innate immune response and bone remodeling are key factors contributing to the pathogenesis of psoriatic arthritis (PsA). Moreover, the evidence of autoantibodies in patients' sera suggests an autoimmune side in PsA. Besides the immune pathways, studies strongly support the role of genetic risk alleles in affecting the clinical heterogeneity of PsA as well as the response to therapy. A good clinical response to treatment, indeed, represents a challenge in PsA patients and the identification of patient-targeted therapies is still a critical issue. Areas covered: We performed a systematic review aiming at describing new evidence on PsA pathogenesis and treatments. Reported items for systematic reviews (PRISMA checklist) were analyzed. Studies included from the PubMed database addressed the following items: innate immunity, autoimmunity, bone remodeling, and therapeutic targets in PsA; time frame of research 1970-2019. Specifically, we reviewed data on IL-17 inhibitors, abatacept, JAK inhibitors, ABT 122, and A (3) adenosine receptors agonist, CF101. Expert opinion: In PsA an intriguing pathogenetic network has been documented. Several biological and synthetic drugs are promising in terms of efficacy and safety profile.

Challenges in the treatment of Rheumatoid Arthritis.

Rheumatoid Arthritis (RA) is a chronic inflammatory disease characterized by a heterogeneous clinical response to the different treatments. Some patients are difficult to treat and do not reach the treatment targets as clinical remission or low disease activity. Known negative prognostic factors, such as the presence of auto-antiantibodies and joint erosion, the presence of a genetic profile, comorbidities and extra-articular manifestations, pregnancy or a pregnancy wish may concur to the treatment failure. In this review we aimed at identify difficult to treat RA patients and define the optimal therapeutic and environmental targets. Genetic markers of severity such as HLA-DRB1, TRAF1, PSORS1C1 and microRNA 146a are differently associated with joint damage; other gene polymorphisms seem to be associated with response to biologic disease modifying anti-rheumatic drugs (bDMARDs). The presence of comorbidities and/or extra-articular manifestations may influence the therapeutic choice; overweight and obese patients are less responsive to TNF inhibitors. In this context the patient profiling can improve the clinical outcome. Targeting different pathways, molecules, and cells involved in the pathogenesis of RA may in part justify the lack response of some patients. An overview of the future therapeutic targets, including bDMARDs (inhibitors of IL-6, GM-CSF, matrix metalloproteinases, chemokines) and targeted synthetic DMARDs (filgotinib, ABT-494, pefacitinib, decernotinib), and environmental targets is addressed. Environmental factors, such as diet and cigarette smoke, may influence susceptibility to autoimmune diseases and interfere with inflammatory pathways. Mediterranean diet, low salt intake, cocoa, curcumin, and physical activity seem to show beneficial effects, however studies of dose finding, safety and efficacy in RA need to be performed.

Evaluation of alexithymia in patients affected by rheumatoid arthritis and psoriatic arthritis: A cross-sectional study.

Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are chronic autoimmune diseases leading to joint damage, functional limitation, and disability and are typically associated with several comorbidities. Alexithymia is a personality trait characterized by a disregulation of emotion processing and regulation of emotions that involves a dissociation of emotional and physical responses to life events. A broad association between alexithymia and symptoms as depression, inflammation, and pain has been demonstrated. We aimed at evaluate an association among inflammatory arthritis, as RA and PsA, and alexithymia, and a possible link with clinical characteristics and disease activity.In this cross-sectional study, we enrolled, from January to December 2017, patients affected by RA or PsA referring to the outpatient's clinic of the Rheumatology Unit of the University of Rome Tor Vergata. The 20-item Toronto Alexithymia Scale (TAS-20) was used to assess alexithymia. Disease activity, function, quality of life, and clinimetric indexes were assessed.A total of 50 RA patients and 51 PsA patients were enrolled. The TAS-20 score showed 38.6% (39/101) patients had alexithymia, 26.7% (27/101) patients were in the borderline of alexithymia and 34.7% (35/101) patients did not have alexithymia. A statistical significant association was observed between alexithymia and inflammatory indices (ESR: P = .029, CRP: P = .043) and between alexithymia and clinimetric parameters (ptVAS, pVAS, GH, P < .0001 for all comparisons). A significant trend of association has been demonstrated between alexithymia and female gender and concomitant steroid therapy. No correlations among variables such as age, duration of disease, and comorbidities and alexithymia status were observed.This study suggests that alexithymia assessment should be a part of the comprehensive management of RA and PsA patients.

Potential Role of Cytochrome c and Tryptase in Psoriasis and Psoriatic Arthritis Pathogenesis: Focus on Resistance to Apoptosis and Oxidative Stress.

Psoriasis (PsO) is an autoimmune disease characterized by keratinocyte proliferation, chronic inflammation and mast cell activation. Up to 42% of patients with PsO may present psoriatic arthritis (PsA). PsO and PsA share common pathophysiological mechanisms: keratinocytes and fibroblast-like synoviocytes are resistant to apoptosis: this is one of the mechanism facilitating their hyperplasic growth, and at joint level, the destruction of articular cartilage, and bone erosion and/or proliferation. Several clinical studies regarding diseases characterized by impairment of cell death, either due to apoptosis or necrosis, reported cytochrome c release from the mitochondria into the extracellular space and finally into the circulation. The presence of elevated cytochrome c levels in serum has been demonstrated in diseases as inflammatory arthritis, myocardial infarction and stroke, and liver diseases. Cytochrome c is a signaling molecule essential for apoptotic cell death released from mitochondria to the cytosol allowing the interaction with protease, as the apoptosis protease activation factor, which lead to the activation of factor-1 and procaspase 9. It has been demonstrated that this efflux from the mitochondria is crucial to start the intracellular signaling responsible for apoptosis, then to the activation of the inflammatory process. Another inflammatory marker, the tryptase, a trypsin-like serine protease produced by mast cells, is released during inflammation, leading to the activation of several immune cells through proteinase-activated receptor-2. In this review, we aimed at discussing the role played by cytochrome c and tryptase in PsO and PsA pathogenesis. To this purpose, we searched pathogenetic mechanisms in PUBMED database and review on oxidative stress, cytochrome c and tryptase and their potential role during inflammation in PsO and PsA. To this regard, the cytochrome c release into the extracellular space and tryptase may have a role in skin and joint inflammation.

Anti-LL37 Antibodies Are Present in Psoriatic Arthritis (PsA) Patients: New Biomarkers in PsA.

Psoriatic arthritis (PsA) is a chronic inflammatory arthritis associated with psoriasis. A third of psoriatic patients develop PsA via unknown mechanisms. No reliable diagnostic markers are available for PsA, or prognostic biomarkers for PsA development in psoriasis. We previously uncovered a pro-inflammatory role for cathelicidin LL37 in lesional psoriasis skin. LL37 binds nucleic acids and stimulates plasmacytoid/myeloid dendritic cells (pDC, mDCs) to secrete type I interferon (IFN-I) and pro-inflammatory factors. LL37 becomes an autoantigen for psoriatic Th1-Th17/CD8 T cells. Anti-LL37 antibodies were detected in systemic lupus erythematosus, an autoimmune disease characterized by neutrophil-extracellular-traps release (NETosis) in target organs. LL37 can be substrate of irreversible post-translational modifications, citrullination or carbamylation, linked to neutrophil activity. Here we analyzed inflammatory factors, included LL37, in PsA and psoriasis plasma and PsA synovial fluids (SF)/biopsies. We show that LL37 (as a product of infiltrating neutrophils) and autoantibodies to LL37 are elevated in PsA, but not OA SF. Anti-LL37 antibodies correlate with clinical inflammatory markers. Anti-carbamylated/citrullinated-LL37 antibodies are present in PsA SF/plasma and, at lower extent, in psoriasis plasma, but not in controls. Plasma anti-carbamylated-LL37 antibodies correlate with PsA (DAS44) but not psoriasis (PASI) disease activity. Ectopic lymphoid structures, and deposition of immunoglobulin-(Ig)G-complexes (IC) co-localizing with infiltrating neutrophils, are observed in PsA and not OA synovial tissues (ST). Activated complement (C5a, C9), GM-CSF and IFN-I are up-regulated in PsA and not OA synovia and in PsA and psoriasis plasma but not in HD. C9 and GM-CSF levels in PsA SF correlate with clinical inflammatory markers and DAS44 (C9) and with anti-carbamylated/citrullinated-LL37 antibodies (GM-CSF and IFN-I). Thus, we uncover a role for LL37 as a novel PsA autoantibody target and correlation studies suggest participation of anti-LL37 antibodies to PsA pathogenesis. Notably, plasma antibodies to carbamylated-LL37, which correlate with DAS44, suggest their use as new disease activity markers. GM-CSF and complement C5a and C9 elevation may be responsible for autoantigens release by neutrophils and their modification, fueling inflammation and autoreactivity establishment. Finally, targeting GM-CSF, C5a, C9 can be beneficial in PsA.

Assessment of data-assisted prediction by inclusion of crosslinking/mass-spectrometry and small angle X-ray scattering data in the 12th Critical Assessment of protein Structure Prediction experiment.

Integrative modeling approaches attempt to combine experiments and computation to derive structure-function relationships in complex molecular assemblies. Despite their importance for the advancement of life sciences, benchmarking of existing methodologies is rather poor. The 12th round of the Critical Assessment of protein Structure Prediction (CASP) offered a unique niche to benchmark data and methods from two kinds of experiments often used in integrative modeling, namely residue-residue contacts obtained through crosslinking/mass-spectrometry (CLMS), and small-angle X-ray scattering (SAXS) experiments. Upon assessment of the models submitted by predictors for 3 targets assisted by CLMS data and 11 targets by SAXS data, we observed no significant improvement when compared to the best data-blind models, although most predictors did improve relative to their own data-blind predictions. Only for target Tx892 of the CLMS-assisted category and for target Ts947 of the SAXS-assisted category, there was a net, albeit mild, improvement relative to the best data-blind predictions. We discuss here possible reasons for the relatively poor success, which point rather to inconsistencies in the data sources rather than in the methods, to which a few groups were less sensitive. We conclude with suggestions that could improve the potential of data integration in future CASP rounds in terms of experimental data production, methods development, data management and prediction assessment.

A rheostat mechanism governs the bifurcation of carbon flux in mycobacteria.

Fatty acid metabolism is an important feature of the pathogenicity of Mycobacterium tuberculosis during infection. Consumption of fatty acids requires regulation of carbon flux bifurcation between the oxidative TCA cycle and the glyoxylate shunt. In Escherichia coli, flux bifurcation is regulated by phosphorylation-mediated inhibition of isocitrate dehydrogenase (ICD), a paradigmatic example of post-translational mechanisms governing metabolic fluxes. Here, we demonstrate that, in contrast to E. coli, carbon flux bifurcation in mycobacteria is regulated not by phosphorylation but through metabolic cross-activation of ICD by glyoxylate, which is produced by the glyoxylate shunt enzyme isocitrate lyase (ICL). This regulatory circuit maintains stable partitioning of fluxes, thus ensuring a balance between anaplerosis, energy production, and precursor biosynthesis. The rheostat-like mechanism of metabolite-mediated control of flux partitioning demonstrates the importance of allosteric regulation during metabolic steady-state. The sensitivity of this regulatory mechanism to perturbations presents a potentially attractive target for chemotherapy.