FtsZ filament structures in different nucleotide states reveal the mechanism of assembly dynamics.

Treadmilling protein filaments perform essential cellular functions by growing from one end while shrinking from the other, driven by nucleotide hydrolysis. Bacterial cell division relies on the primitive tubulin homolog FtsZ, a target for antibiotic discovery that assembles into single treadmilling filaments that hydrolyse GTP at an active site formed upon subunit association. We determined high-resolution filament structures of FtsZ from the pathogen Staphylococcus aureus in complex with different nucleotide analogs and cations, including mimetics of the ground and transition states of catalysis. Together with mutational and biochemical analyses, our structures reveal interactions made by the GTP γ-phosphate and Mg2+ at the subunit interface, a K+ ion stabilizing loop T7 for co-catalysis, new roles of key residues at the active site and a nearby crosstalk area, and rearrangements of a dynamic water shell bridging adjacent subunits upon GTP hydrolysis. We propose a mechanistic model that integrates nucleotide hydrolysis signaling with assembly-associated conformational changes and filament treadmilling. Equivalent assembly mechanisms may apply to more complex tubulin and actin cytomotive filaments that share analogous features with FtsZ.

The Versatility of Collagen in Pharmacology: Targeting Collagen, Targeting with Collagen.

Collagen, a versatile family of proteins with 28 members and 44 genes, is pivotal in maintaining tissue integrity and function. It plays a crucial role in physiological processes like wound healing, hemostasis, and pathological conditions such as fibrosis and cancer. Collagen is a target in these processes. Direct methods for collagen modulation include enzymatic breakdown and molecular binding approaches. For instance, Clostridium histolyticum collagenase is effective in treating localized fibrosis. Polypeptides like collagen-binding domains offer promising avenues for tumor-specific immunotherapy and drug delivery. Indirect targeting of collagen involves regulating cellular processes essential for its synthesis and maturation, such as translation regulation and microRNA activity. Enzymes involved in collagen modification, such as prolyl-hydroxylases or lysyl-oxidases, are also indirect therapeutic targets. From another perspective, collagen is also a natural source of drugs. Enzymatic degradation of collagen generates bioactive fragments known as matrikines and matricryptins, which exhibit diverse pharmacological activities. Overall, collagen-derived peptides present significant therapeutic potential beyond tissue repair, offering various strategies for treating fibrosis, cancer, and genetic disorders. Continued research into specific collagen targeting and the application of collagen and its derivatives may lead to the development of novel treatments for a range of pathological conditions.

What do patients on methotrexate need and expect at the clinic? An online patient survey.

To verify, via a survey, the experience and needs of patients receiving methotrexate (MTX), their general management and the quality of the information provided by the rheumatologist. We conducted a 51-item online survey between May and July 2020 addressed to persons diagnosed with an immune-mediated disease and treated with MTX (regardless of the route of administration). Recruitment was done via Twitter. We obtained 294 responses, of which 283 were complete and could be analysed. Almost 82% of the respondents were women, 80% resided in Spain, 75% were between 31 and 60 years old, and 57% were active workers. Diseases included psoriasis (41%), lupus, Sjögren's or vasculitides (33%), and rheumatoid arthritis (16%), among others. Eighty per cent had read the leaflet inserted in the package, of whom 62% found it helpful. Only 15% of the respondents reported having been offered additional written material, which was considered barely functional (33 out of 100). Most patients (88%) responded that they had not received advice on any reliable sources to consult on the internet, and those who received it considered it unhelpful (24 out of 100). Patients receiving MTX due to an autoimmune disease demand more and better-quality written or web-based information than what is currently offered at their clinics.

Usnea aurantiaco-atra (Jacq) Bory: Metabolites and Biological Activities.

BACKGROUND: Lichens are complex symbiotic associations between a fungus and an alga or cyanobacterium. Due to their great adaptability to the environment, they have managed to colonize many terrestrial habitats, presenting a worldwide distribution from the poles to the tropical regions and from the plains to the highest mountains. In the flora of the Antarctic region, lichens stand out due to their variety and development and are a potential source of new bioactive compounds. METHODS: A phytochemical study of the Antarctic lichen Usnea aurantiaco-atra (Jacq) Bory was conducted with the intention of determining the most important metabolites. In addition, the cytotoxic and antioxidant activities of its extracts were determined. RESULTS: Cytotoxicity studies revealed that the hexane extract contains usnic acid as a majority metabolite, in addition to linoleic acid, ergosterols and terpenes, and demonstrates cytotoxic activity against an A375 melanoma cell line. On the other hand, the presence of total phenols in the extracts did not influence their antioxidant activity. CONCLUSIONS: U. aurantiaco-atra contains mainly usnic acid, although there are terpenes and ergosta compounds that could be responsible for its cytotoxic activity. The presence of phenols did not confer antioxidant properties.

Biologic therapy in refractory neurobehçet's disease: a multicentre study of 41 patients and literature review.

OBJECTIVES: To assess efficacy and safety of biologic therapy (BT) in neurobehçet's disease (NBD) refractory to glucocorticoids and at least one conventional immunosuppressive drug. METHODS: Open-label, national, multicentre study. NBD diagnosis was based on the International Consensus Recommendation criteria. Outcome variables were efficacy and safety. Main efficacy outcome was clinical remission. Other outcome variables analysed were glucocorticoid-sparing effect and improvement in laboratory parameters. RESULTS: We studied 41 patients [21 women; age 40.6 (10.8) years]. Neurological damage was parenchymal (n = 33, 80.5%) and non-parenchymal (n = 17, 41.5%). First BTs used were infliximab (n = 19), adalimumab (n = 14), golimumab (n = 3), tocilizumab (n = 3) and etanercept (n = 2). After 6 months of BT, neurological remission was complete (n = 23, 56.1%), partial (n = 15, 37.6%) and no response (n = 3, 7.3%). In addition, median (IQR) dose of oral prednisone decreased from 60 (30-60) mg/day at the initial visit to 5 (3.8-10) mg/day after 6 months (P < 0.001). It was also the case for mean erythrocyte sedimentation rate [31.5 (25.6)-15.3 (11.9) mm/1st h, P = 0.011] and median (IQR) C-reactive protein [1.4 (0.2-12.8) to 0.3 (0.1-3) mg/dl, P = 0.001]. After a mean follow-up of 57.5 months, partial or complete neurological remission persisted in 37 patients (90.2%). BT was switched in 22 cases (53.6%) due to inefficacy (n = 16) or adverse events (AEs) (n = 6) and discontinued due to complete prolonged remission (n = 3) or severe AE (n = 1). Serious AEs were observed in two patients under infliximab treatment. CONCLUSIONS: BT appears to be effective and relatively safe in refractory NBD.

SP1 and NFY Regulate the Expression of PNPT1, a Gene Encoding a Mitochondrial Protein Involved in Cancer.

The Polyribonucleotide nucleotidyltransferase 1 gene (PNPT1) encodes polynucleotide phosphorylase (PNPase), a 3'-5' exoribonuclease involved in mitochondrial RNA degradation and surveillance and RNA import into the mitochondrion. Here, we have characterized the PNPT1 promoter by in silico analysis, luciferase reporter assays, electrophoretic mobility shift assays (EMSA), chromatin immunoprecipitation (ChIP), siRNA-based mRNA silencing and RT-qPCR. We show that the Specificity protein 1 (SP1) transcription factor and Nuclear transcription factor Y (NFY) bind the PNPT1 promoter, and have a relevant role regulating the promoter activity, PNPT1 expression, and mitochondrial activity. We also found in Kaplan-Meier survival curves that a high expression of either PNPase, SP1 or NFY subunit A (NFYA) is associated with a poor prognosis in liver cancer. In summary, our results show the relevance of SP1 and NFY in PNPT1 expression, and point to SP1/NFY and PNPase as possible targets in anti-cancer therapy.

Relevance of gastrointestinal manifestations in a large Spanish cohort of patients with systemic lupus erythematosus: what do we know?

OBJECTIVE: SLE can affect any part of the gastrointestinal (GI) tract. GI symptoms are reported to occur in >50% of SLE patients. To describe the GI manifestations of SLE in the RELESSER (Registry of SLE Patients of the Spanish Society of Rheumatology) cohort and to determine whether these are associated with a more severe disease, damage accrual and a worse prognosis. METHODS: We conducted a nationwide, retrospective, multicentre, cross-sectional cohort study of 3658 SLE patients who fulfil ≥4 ACR-97 criteria. Data on demographics, disease characteristics, activity (SLEDAI-2K or BILAG), damage (SLICC/ACR/DI) and therapies were collected. Demographic and clinical characteristics were compared between lupus patients with and without GI damage to establish whether GI damage is associated with a more severe disease. RESULTS: From 3654 lupus patients, 3.7% developed GI damage. Patients in this group (group 1) were older, they had longer disease duration, and were more likely to have vasculitis, renal disease and serositis than patients without GI damage (group 2). Hospitalizations and mortality were significantly higher in group 1. Patients in group 1 had higher modified SDI (SLICC Damage Index). The presence of oral ulcers reduced the risk of developing damage in 33% of patients. CONCLUSION: Having GI damage is associated with a worse prognosis. Patients on a high dose of glucocorticoids are at higher risk of developing GI damage which reinforces the strategy of minimizing glucocorticoids. Oral ulcers appear to decrease the risk of GI damage.

Synthetic developmental regulator MciZ targets FtsZ across Bacillus species and inhibits bacterial division.

Cell division in most bacteria is directed by FtsZ, a conserved tubulin-like GTPase that assembles forming the cytokinetic Z-ring and constitutes a target for the discovery of new antibiotics. The developmental regulator MciZ, a 40-amino acid peptide endogenously produced during Bacillus subtilis sporulation, halts cytokinesis in the mother cell by inhibiting FtsZ. The crystal structure of a FtsZ:MciZ complex revealed that bound MciZ extends the C-terminal ß-sheet of FtsZ blocking its assembly interface. Here we demonstrate that exogenously added MciZ specifically inhibits B. subtilis cell division, sporulation and germination, and provide insight into MciZ molecular recognition by FtsZ from different bacteria. MciZ and FtsZ form a complex with sub-micromolar affinity, analyzed by analytical ultracentrifugation, laser biolayer interferometry and isothermal titration calorimetry. Synthetic MciZ analogs, carrying single amino acid substitutions impairing MciZ ß-strand formation or hydrogen bonding to FtsZ, show a gradual reduction in affinity that resembles their impaired activity in bacteria. Gene sequences encoding MciZ spread across genus Bacillus and synthetic MciZ slows down cell division in Bacillus species, including pathogenic Bacillus cereus and Bacillus anthracis. Moreover, B. subtilis MciZ is recognized by the homologous FtsZ from Staphylococcus aureus and inhibits division when it is expressed into S. aureus cells.

Abatacept in interstitial lung disease associated with rheumatoid arthritis: national multicenter study of 263 patients.

OBJECTIVE: To assess the efficacy of abatacept (ABA) in RA patients with interstitial lung disease (ILD) (RA-ILD). METHODS: This was an observational, multicentre study of RA-ILD patients treated with at least one dose of ABA. ILD was diagnosed by high-resolution CT (HRCT). We analysed the following variables at baseline (ABA initiation), 12 months and at the end of the follow-up: Modified Medical Research Council (MMRC) scale (1-point change), forced vital capacity (FVC) or diffusion lung capacity for carbon monoxide (DLCO) (improvement or worsening ≥10%), HRCT, DAS on 28 joints evaluated using the ESR (DAS28ESR) and CS-sparing effect. RESULTS: We studied 263 RA-ILD patients [150 women/113 men; mean (s.d.) age 64.6 (10) years]. At baseline, they had a median duration of ILD of 1 (interquartile range 0.25-3.44) years, moderate or severe degree of dyspnoea (MMRC grade 2, 3 or 4) (40.3%), FVC (% of the predicted) mean (s.d.) 85.9 (21.8)%, DLCO (% of the predicted) 65.7 (18.3) and DAS28ESR 4.5 (1.5). The ILD patterns were: usual interstitial pneumonia (UIP) (40.3%), non-specific interstitial pneumonia (NSIP) (31.9%) and others (27.8%). ABA was prescribed at standard dose, i.v. (25.5%) or s.c. (74.5%). After a median follow-up of 12 (6-36) months the following variables did not show worsening: dyspnoea (MMRC) (91.9%); FVC (87.7%); DLCO (90.6%); and chest HRCT (76.6%). A significant improvement of DAS28ESR from 4.5 (1.5) to 3.1 (1.3) at the end of follow-up (P < 0.001) and a CS-sparing effect from a median 7.5 (5-10) to 5 (2.5-7.5) mg/day at the end of follow-up (P < 0.001) was also observed. ABA was withdrawn in 62 (23.6%) patients due to adverse events (n = 30), articular inefficacy (n = 27), ILD worsening (n = 3) and other causes (n = 2). CONCLUSION: ABA may be an effective and safe treatment for patients with RA-ILD.

Clinically significant renal involvement in primary Sjögren's syndrome is associated with important morbidity: data from the Spanish Sjögrenser cohort.

OBJECTIVES: To investigate the prevalence, associated factors, and effects of primary overt renal disease on morbidity in patients with primary Sjögren's syndrome (pSS). METHODS: All patients in the Sjögrenser (registry of adult pSS patients of the Spanish Society of Rheumatology) cohort were retrospectively investigated for the presence of clinically significant renal involvement directly related to pSS activity. RESULTS: Of the 437 patients investigated, 39 (9%) presented overt renal involvement during follow-up. Severe renal disease necessitating kidney biopsy was relatively rare (2%). Renal involvement may complicate pSS at any time during the disease course and is associated with severe disease (indicated by higher scores of involvement, activity, and damage), systemic multiorgan involvement, and a higher frequency of lymphoma. Multivariate analysis showed that older age (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.00-1.07), higher European League Against Rheumatism Sjögren's Syndrome Disease Activity Index scores (OR 1.1, CI 1.03-1.18), serum anti-La/SSB positivity (OR 6.65, CI 1.41-31.372), and non-vasculitic cutaneous involvement (OR 5.47, 1.03-29.02) were independently associated with this complication. Chronic renal failure developed in 23 of 39 patients (59%); only 1 of them progressed to end-stage renal disease necessitating renal replacement therapy. Patients with overt renal disease showed higher Sjögren's syndrome disease damage index scores, higher rates of hospitalisation due to disease activity and higher rates of clinically relevant comorbidities. CONCLUSIONS: Overt renal involvement in pSS is not uncommon. Although it usually shows a favourable prognosis, is associated with significant morbidity.

"There is something you must see": breaking down the remission concept in rheumatoid arthritis from a rheumatologist's perspective.

OBJECTIVES: To explore the remission concept in rheumatoid arthritis (RA) and the implications of the existing definitions when applied to clinical practice among rheumatologists with different profiles. METHODS: A qualitative study through focus groups was conducted. Three focus groups were organised from February to March 2016. Each group was composed of rheumatologists with extensive clinical experience with different profiles; experts in basic research (RBR), experts in imaging techniques research (RIR), and experts in clinical research (RCR). The data was collected with audio recording. Verbatim transcriptions of the audio files were made, and a subsequent reflexive thematic analysis assisted by ATLAS.ti (GmbH, Berlin, v. 7) software was performed. RESULTS: From the reflexive thematic analysis, three main themes were generated: (1) remission limitations, (2) instruments or measures to assess remission, and (3) a new definition of remission. Rheumatologists mentioned frequently that the following variables should be considered when developing a new remission definition: inflammatory activity, calprotectin, psychological variables, sex, disease stage, and sociocultural factors. Contrary to what could be expected, all groups acknowledged that their research field could contribute with domains for a gold standard remission instrument, but not in a hierarchical arrangement of importance. The dissonance existing in the entire remission evaluation process was outlined: remission in clinical practice versus remission in clinical trials, remission following the American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) Boolean versus Musculoskeletal Ultrasound (US) remission, and remission from the rheumatologist's point of view versus the patient's point of view. CONCLUSIONS: Currently, rheumatologists would not accept a domain as more important than others in remission. Our suggestion is, not to generate a universal definition of remission - one that could cover all aspects - but rather to develop definitions of remission for the different settings that could be pondered by the patient's perspective.

Digestive involvement in primary Sjögren's syndrome: analysis from the Sjögrenser registry.

OBJECTIVES: Digestive involvement (DI) has been reported in 10-30% of primary Sjögren's syndrome (pSS) patients, and few studies have systematically analysed the prevalence of DI in pSS patients. The aim of this study was to describe DI prevalence in pSS patients from the Sjögrenser Study, and to analyse its clinical associations. METHODS: All patients included in the Sjögrenser study, a Spanish multicentre randomised cohort, containing demographic, clinical and histologic data, have been analysed retrospectively. Patients were classified according to the presence of DI (oesophageal, gastric, intestinal, hepatic and pancreatic), and we have performed DI clinical associations, descriptive statistics, Student t or χ2 test, and uni and multivariate logistic regression. RESULTS: From 437 included patients, 95% were women, with a median age of 58 years, 71 (16.2%) presented DI: 21 (29.5%) chronic atrophic gastritis, 12 (16.9%) oesophageal motility dysfunction, 3 (4.2%) lymphocytic colitis, 18 (25.3%) primary biliary cholangitis, 15 (21.1%) autoimmune hepatitis, 7 (9.8%) pancreatic involvement and 5 (7%) coeliac disease. Half of them developed DI at the same time or after pSS diagnosis. Patients with DI were significantly older at pSS diagnosis (p=0.032), more frequently women (p=0.009), presented more autoimmune hypothyroidism and C3 hypocomplementaemia (p=0.040), and were treated more frequently with glucocorticoids, immunosuppressant and biologic therapies. Patients with pancreatic involvement presented more central nervous system and renal involvement, Raynaud's phenomenon, lymphoma and C3/C4 hypocomplementaemia. CONCLUSIONS: DI is frequent in Sjögrenser patients, mainly in the form of autoimmune disorders, and seem to be associated with a more severe phenotype. Our results suggest that DI should be evaluated in pSS patients, especially those with more severe disease.

Prevalence and factors associated with osteoporosis and fragility fractures in patients with primary Sjögren syndrome.

This study aimed at determining socio-demographic and clinical factors of primary Sjögren syndrome (pSS) associated with osteoporosis (OP) and fragility fracture. SJOGRENSER is a cross-sectional study of patients with pSS, classified according to American European consensus criteria developed in 33 Spanish rheumatology departments. Epidemiological, clinical, serological and treatment data were collected and a descriptive analysis was conducted. Bivariate and multivariate analyses were performed using a binomial logistic regression to study the factors associated with OP and fragility fracture in pSS. 437 patients were included (95% women, with a median age of 58.6 years). 300 women were menopausal (76.4%). Prevalence of OP was 18.5% [in men (N = 21) this measured 19%]. A total of 37 fragility fractures were recorded. In the multivariate analysis, there was an association between OP and age: in the 51-64 age range (menopausal women), the OR measured 9.993 (95% CI 2301-43,399, p = 0.002); In the age > 64 years group, OR was 20.610 (4.679-90.774, p < 0.001); between OP and disease duration, OR was 1.046 (1.008-1085, p = 0.017); past treatment with corticosteroids, OR 2.548 (1.271-5.105, p = 0.008). Similarly, an association was found between fragility fractures and age: in the 51-64 age group, OR measured 5.068 (1.117-22,995, p = 0.035), age > 64 years, OR was 7.674 (1.675-35,151, p < 0.009); disease duration, OR 1.049 (CI 1.003-1097, p < 0.036) and the ESSDAI index, OR 1.080 (1.029-1134, p = 0.002). Patients with pSS can develop osteoporosis and fragility fractures over the course of the disease. Age, corticosteroids treatment and disease duration were associated with the development of OP. Disease duration and ESSDAI were associated with the development of fractures in patients with pSS.

Clinical and genetic characteristics of ankylosing spondylitis patients with peripheral arthritis at disease onset.

OBJECTIVES: The aim of this study was to assess the clinical and genetic characteristics associated with the presence of peripheral arthritis (PA) at disease onset in patients with ankylosing spondylitis (AS). METHODS: 456 Spanish AS patients, diagnosed according to the modified New York Criteria, who had at least ten years of follow-up since initial disease onset were selected from the National Spondyloarthropathies Registry (REGISPONSER). 18.9% of AS patients initially presented PA. Clinical variables and 384 single nucleotide polymorphisms (SNPs) distributed in 190 genes were analysed. SNP genotyping was performed using the Illumina GoldenGate genotyping platform. Association tests for allele frequencies and for categorical clinical variables were performed by the χ2 test and with the unpaired t-test for continuous variables. p-values of <0.05 were considered statistically significant. RESULTS: AS patients with PA showed an earlier age of disease onset (p=0.021), longer disease duration (p=0.020) and longer duration of AS symptoms from onset (p=0.034) than AS patients without PA. We found significant associations with the presence of PA at disease onset in 14 SNPs located in 10 genes: HLA-DQB2 (rs2857210 and rs9276615), HLA-DOB (rs2857151, rs2621332 and rs1383261), JAK2 (rs7857730), IL-23R (rs11209008 and rs10489630), CYP1B1 (rs1056836), NELL1 (rs8176786), KL (rs564481), and MEFV (rs224204), IL-2RB (rs743777) and IL-1A (rs1800587). CONCLUSIONS: Both clinical and genetic factors are associated with the presence of PA at disease onset in Spanish AS patients. The results suggest that this subset of AS patients with PA at disease onset might have differentiation factors involved in disease pathogenesis.

ESSDAI activity index of the SJÖGRENSER cohort: analysis and comparison with other European cohorts.

The objective of the study was to assess the ESSDAI index characteristics in the SJÖGRENSER cohort (Spanish Rheumatology Association's registry of patients with Primary Sjögren Syndrome [PSS]). SJÖGRENSER is a prospective multicentric study on a cohort of Spanish patients with PSS who meet the 2002 American-European consensus from rheumatology units. 298 variables were studied in patients for the inclusion of the study from an anonymous list from each department. The ESSDAI (EULAR Sjögren's syndrome disease activity index) includes 12 domains and measures systematic activity in PSS patients. Each domain is divided into 3-4 levels, (0: no activity; 1: low activity; 2: moderate activity; 3: high activity) and is attributed a weight. Each domain score is obtained by multiplying the activity level by the weight assigned. According to ESSDAI: low activity < 5; moderate activity 5-13, and high activity ≥ 14. ESSDAI was compared between several European PSS cohorts (EULAR, ASSES, GEAS, GRISS, Ducth). 437 patients were included from 33 Spanish rheumatology units. 95.2% were women with a median age of 58.63 years [p25-p75: 50.02-67.98 years] and average PSS evolution of 10.4 years (6-16 years). ESSDAI median on entering the study was 2 (0-4). 31% of patients had ESSDAI 0; low activity 49%, moderate activity 15%, and high activity 5%. Those with greater activity were the joint, haematological and biological domains, whereas the lung was the most affected organ with pleural and parenchymatous involvement. Unlike other European cohorts, the initial SJÖGRENSER cohort was characterised by low-zero systemic activity in 80% of patients, which differentiates it from other cohorts and provides a prospective study opportunity.

The Conception of Synthetic Entities from a Personalist Perspective.

Synthetic biology opens up the possibility of producing new entities not found in nature, whose classification as organisms or machines has been debated. In this paper we are focusing on the delimitation of the moral value of synthetic products, in order to establish the ethically right way to behave towards them. In order to do so, we use personalism as our ethical framework. First, we examine how we can distinguish between organisms and machines. Next, we discuss whether the products of synthetic biology can be considered organisms at all and assess what their moral value is and how should we behave towards them. Finally, we discuss the hypothetical case of synthetic humans.

Gender differences in early systemic sclerosis patients: a report from the EULAR scleroderma trials and research group (EUSTAR) database.

OBJECTIVES: To describe differences in clinical presentation between men and women in a large group of patients with early (<3 years' duration) systemic sclerosis (SSc) according to disease subsets. METHODS: A cross-sectional analysis of the prospective EULAR Scleroderma Trial and Research database (EUSTAR) was performed. Patients fulfilling preliminary ACR 1980 classification criteria for SSc, with less than 3 years from the first non-Raynaud's symptom at first entry, were selected. A group of patients with less than 3 years from the first SSc symptom, including Raynaud's phenomenon, was also analysed. SSc related variables, including antibodies, SSc subsets, disease activity and organ involvement were included. Descriptive and bivariate analyses were performed. RESULTS: A total of 1,027 patients were included, 90% Caucasian, 80% women, and 40% with diffuse cutaneous disease. In early stages of SSc, men showed more frequently than women active disease, diffuse cutaneous subset, anti-Scl-70 antibodies, elevated acute phase reactants, muscular and pulmonary involvement. Differences between men and women were confirmed in the limited, but not in the diffuse SSc subset. The results were similar when 650 patients with less than three years from the first SSc symptom, including Raynaud's phenomenon, were analysed. CONCLUSIONS: In early stages of SSc, men present signs and symptoms of more severe disease. In the limited disease subset, men might appear with clinical features and organ involvement similar to those of the diffuse subgroup. In clinical practice, the identification of such differences might help to select the appropriate management for each particular patient.

Zampanolide Binding to Tubulin Indicates Cross-Talk of Taxane Site with Colchicine and Nucleotide Sites.

The marine natural product zampanolide and analogues thereof constitute a new chemotype of taxoid site microtubule-stabilizing agents with a covalent mechanism of action. Zampanolide-ligated tubulin has the switch-activation loop (M-loop) in the assembly prone form and, thus, represents an assembly activated state of the protein. In this study, we have characterized the biochemical properties of the covalently modified, activated tubulin dimer, and we have determined the effect of zampanolide on tubulin association and the binding of tubulin ligands at other binding sites. Tubulin activation by zampanolide does not affect its longitudinal oligomerization but does alter its lateral association properties. The covalent binding of zampanolide to ß-tubulin affects both the colchicine site, causing a change of the quantum yield of the bound ligand, and the exchangeable nucleotide binding site, reducing the affinity for the nucleotide. While these global effects do not change the binding affinity of 2-methoxy-5-(2,3,4-trimethoxyphenyl)-2,4,6-cycloheptatrien-1-one (MTC) (a reversible binder of the colchicine site), the binding affinity of a fluorescent analogue of GTP (Mant-GTP) at the nucleotide E-site is reduced from 12 ± 2 × 105 M-1 in the case of unmodified tubulin to 1.4 ± 0.3 × 105 M-1 in the case of the zampanolide tubulin adduct, indicating signal transmission between the taxane site and the colchicine and nucleotide sites of ß-tubulin.

Factors associated with severe dry eye in primary Sjögren's syndrome diagnosed patients.

INTRODUCTION: Primary Sjögren's syndrome (pSS) is an autoimmune disease, characterized by lymphocytic infiltration of exocrine glands and other organs, resulting in dry eye, dry mouth and extraglandular systemic findings. OBJECTIVE: To explore the association of severe or very severe dry eye with extraocular involvement in patients diagnosed with primary Sjögren's syndrome. METHODS: SJOGRENSER registry is a multicenter cross-sectional study of pSS patients. For the construction of our main variable, severe/very severe dry eye, we used those variables that represented a degree 3-4 of severity according to the 2007 Dry Eye Workshop classification. First, bivariate logistic regression models were used to identify the effect of each independent variable on severe/very severe dry eye. Secondly, multivariate analysis using regression model was used to establish the independent effect of patient characteristics. RESULTS: Four hundred and thirty-seven patients were included in SJOGRENSER registry; 94% of the patients complained of dry eye and 16% developed corneal ulcer. Schirmer's test was pathological in 92% of the patients; 378 patients presented severe/very severe dry eye. Inflammatory articular involvement was significantly more frequent in patients with severe/very severe dry eye than in those without severe/very severe dry eye (82.5 vs 69.5%, p = 0,028). Inflammatory joint involvement was associated with severe/very severe dry eye in the multivariate analysis, OR 2.079 (95% CI 1.096-3.941). CONCLUSION: Severe or very severe dry eye is associated with the presence of inflammatory joint involvement in patients with pSS. These results suggest that a directed anamnesis including systemic comorbidities, such as the presence of inflammatory joint involvement or dry mouth in patients with dry eye, would be useful to suspect a pSS.

Self-Organization of FtsZ Polymers in Solution Reveals Spacer Role of the Disordered C-Terminal Tail.

FtsZ is a self-assembling GTPase that forms, below the inner membrane, the mid-cell Z-ring guiding bacterial division. FtsZ monomers polymerize head to tail forming tubulin-like dynamic protofilaments, whose organization in the Z-ring is an unresolved problem. Rather than forming a well-defined structure, FtsZ protofilaments laterally associate in vitro into polymorphic condensates typically imaged on surfaces. We describe here nanoscale self-organizing properties of FtsZ assemblies in solution that underlie Z-ring assembly, employing time-resolved x-ray scattering and cryo-electron microscopy. We find that FtsZ forms bundles made of loosely bound filaments of variable length and curvature. Individual FtsZ protofilaments further bend upon nucleotide hydrolysis, highlighted by the observation of some large circular structures with 2.5-5° curvature angles between subunits, followed by disassembly end-products consisting of highly curved oligomers and 16-subunit -220 Å diameter mini-rings, here observed by cryo-electron microscopy. Neighbor FtsZ filaments in bundles are laterally spaced 70 Å, leaving a gap in between. In contrast, close contact between filament core structures (∼50 Å spacing) is observed in straight polymers of FtsZ constructs lacking the C-terminal tail, which is known to provide a flexible tether essential for FtsZ functions in cell division. Changing the length of the intrinsically disordered C-tail linker modifies the interfilament spacing. We propose that the linker prevents dynamic FtsZ protofilaments in bundles from sticking to one another, holding them apart at a distance similar to the lateral spacing observed by electron cryotomography in several bacteria and liposomes. According to this model, weak interactions between curved polar FtsZ protofilaments through their the C-tails may facilitate the coherent treadmilling dynamics of membrane-associated FtsZ bundles in reconstituted systems, as well as the recently discovered movement of FtsZ clusters around bacterial Z-rings that is powered by GTP hydrolysis and guides correct septal cell wall synthesis and cell division.