Complement Biosynthesis in Human Synovial Tissue

The complement system, which comprises a group of at least 20 plasma proteins, plays a major role in host defence against bacterial infections and in immunologically-mediated inflammation. The pro-inflammatory biological activities generated as a result of complement activation include increased vascular permeability, chemotaxis of neutrophils and mononuclear phagocytes, enzyme secretion by phagocytic cells and cytolysis. Complement activation occurs within inflamed synovial joints of patients with rheumatoid arthritis and is thought to play a role in the pathogenesis of the condition. Although plasma levels of most complement components are maintained by hepatic synthesis, the cell responsible being the hepatocyte, it is now well established that other cells including monocytes, macrophages, fibroblasts and epithelial cells of the gastrointestinal and genitourinary tracts synthesise complement components when cultured in vitro. Such cells are potential sources of extrahepatic synthesis of complement components in vivo. Synovial fluid macrophages and adherent synovial membrane cells have been shown to synthesise complement components when cultured in vitro, as have isolated fragments of synovial membrane from patients with either rheumatoid arthritis or osteoarthritis. However, the only evidence for extrahepatic synthesis occurring in vivo comes from metabolic studies with radiolabelled (125I) C3, which indicated that up to 50% of C3 present in the rheumatoid joint was synthesised locally. The principal aim of this study was to provide conclusive evidence that a large number of complement components including C4, C2, C3, C5, factor B and C1-inhibitor, were synthesised in synovial tissue in vivo. The availability of cDNA probes for these complement components allowed the use of molecular biological technology, in addition to immunochemical techniques, to study complement biosynthesis by synovial tissue from patients with rheumatoid arthritis or osteoarthritis and by normal synovial tissue from a patient undergoing patellectomy. Using Northern and dot-blot analyses, mRNAs coding for C1-inhibitor (2.1 kb), factor B (2.6 kb), C1q B-chain (1.4 kb), C2 (2.9 kb), C3 (5.2 kb) and C4 (5.5 kb) were detected in RNA isolated from both rheumatoid synovium and synovial membrane from osteoarthritis patients. Although the presence of C5 mRNA was also investigated, it was not detected in any sample. Dot-blot analysis showed the presence of mRNA coding for C1-inhibitor in RNA isolated from normal synovial membrane. Quantitative analyses of the data using the students t-test did not show any statistically significant difference between the steady state levels of C3, C1-inhibitor or factor B mRNA in synovium from rheumatoid arthritis and osteoarthritis patients. Although ' the levels of C2 mRNA were significantly higher in rheumatoid synovium, and C4 mRNA levels were higher in osteoarthritis synovium, the P value was only marginally significant in both cases (0. 05). When fragments of normal synovium or synovial membrane fragments from patients with rheumatoid arthritis or osteoarthritis, were cultured in vitro, synthesis of C1-inhibitor, C2, C3, C4 and factor B was detected by ELISA and C2, C3 and factor B were shown to be functionally active. Following the demonstration of complement biosynthesis in synovial tissue in vivo, the next step would be to identify the cells within the synovium reponsible for complement biosynthesis. A number of cell-types that are present in synovial membrane have previously been shown to be capable of synthesising complement components in vitro. These include mononuclear phagocytes and possibly the B-cells of the synovial membrane lining, fibroblasts and endothelial cells. However, the cells responsible for complement biosynthesis in vivo remain unidentified. This question may only be answered with the use of in situ hybridisation on frozen sections of synovial tissue. As an initial step in this study, cells were isolated from synovial tissue of patients with rheumatoid arthritis and osteoarthritis and cultured in vitro, ELISA analyses of the culture supernatants showed synthesis of C4, C3, factor B and C1-inhibitor by both the adherent and non-adherent synovial cells. Immunohistochemistry showed that in both cell populations, fibroblasts were present in by far the greatest abundance (>95%), although a small proportion (5%) of macrophages was identified. This study thus provides conclusive evidence that synthesis of complement components occurs locally within normal and inflamed synovial tissue in vivo. The local synthesis of complement within normal synovial joints may be of importance in their defence against infection, whereas in inflamed joints it may contribute to the inflammatory response. Further work is required to define the regulation of complement synthesis within the synovial joint as well as to identify the cells responsible for complement biosynthesis in vivo

Characterisation of a novel Fc conjugate of Macrophage Colony-Stimulating Factor (CSF1)

We have produced an Fc conjugate of colony-stimulating factor (CSF) 1 with an improved circulating half-life. CSF1-Fc retained its macrophage growth-promoting activity, and did not induce proinflammatory cytokines in vitro. Treatment with CSF1-Fc did not produce adverse effects in mice or pigs. The impact of CSF1-Fc was examined using the Csf1r-enhanced green fluorescent protein (EGFP) reporter gene in MacGreen mice. Administration of CSF1-Fc to mice drove extensive infiltration of all tissues by Csf1r-EGFP positive macrophages. The main consequence was hepatosplenomegaly, associated with proliferation of hepatocytes. Expression profiles of the liver indicated that infiltrating macrophages produced candidate mediators of hepatocyte proliferation including urokinase, tumor necrosis factor, and interleukin 6. CSF1-Fc also promoted osteoclastogenesis and produced pleiotropic effects on other organ systems, notably the testis, where CSF1-dependent macrophages have been implicated in homeostasis. However, it did not affect other putative CSF1 targets, notably intestine, where Paneth cell numbers and villus architecture were unchanged. CSF1 has therapeutic potential in regenerative medicine in multiple organs. We suggest that the CSF1-Fc conjugate retains this potential, and may permit daily delivery by injection rather than continuous infusion required for the core molecule

Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

Evaluation of Musical Creativity and Musical Metacreation Systems

The field of computational creativity, including musical metacreation, strives to develop artificial systems that are capable of demonstrating creative behavior or producing creative artefacts. But the claim of creativity is often assessed, subjectively only on the part of the researcher and not objectively at all. This article provides theoretical motivation for more systematic evaluation of musical metacreation and computationally creative systems and presents an overview of current methods used to assess human and machine creativity that may be adapted for this purpose. In order to highlight the need for a varied set of evaluation tools, a distinction is drawn among three types of creative systems: those that are purely generative, those that contain internal or external feedback, and those that are capable of reflection and self-reflection. To address the evaluation of each of these aspects, concrete examples of methods and techniques are suggested to help researchers (1) evaluate their systems' creative process and generated artefacts, and test their impact on the perceptual, cognitive, and affective states of the audience, and (2) build mechanisms for reflection into the creative system, including models of human perception and cognition, to endow creative systems with internal evaluative mechanisms to drive self-reflective processes. The first type of evaluation can be considered external to the creative system and may be employed by the researcher to both better understand the efficacy of their system and its impact and to incorporate feedback into the system. Here we take the stance that understanding human creativity can lend insight to computational approaches, and knowledge of how humans perceive creative systems and their output can be incorporated into artificial agents as feedback to provide a sense of how a creation will impact the audience. The second type centers around internal evaluation, in which the system is able to reason about its own behavior and generated output. We argue that creative behavior cannot occur without feedback and reflection by the creative/metacreative system itself. More rigorous empirical testing will allow computational and metacreative systems to become more creative by definition and can be used to demonstrate the impact and novelty of particular approaches

Dipeptidyl peptidase-1 inhibition in patients hospitalised with COVID-19: a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial

Background Neutrophil serine proteases are involved in the pathogenesis of COVID-19 and increased serine protease activity has been reported in severe and fatal infection. We investigated whether brensocatib, an inhibitor of dipeptidyl peptidase-1 (DPP-1; an enzyme responsible for the activation of neutrophil serine proteases), would improve outcomes in patients hospitalised with COVID-19. Methods In a multicentre, double-blind, randomised, parallel-group, placebo-controlled trial, across 14 hospitals in the UK, patients aged 16 years and older who were hospitalised with COVID-19 and had at least one risk factor for severe disease were randomly assigned 1:1, within 96 h of hospital admission, to once-daily brensocatib 25 mg or placebo orally for 28 days. Patients were randomly assigned via a central web-based randomisation system (TruST). Randomisation was stratified by site and age (65 years or ≥65 years), and within each stratum, blocks were of random sizes of two, four, or six patients. Participants in both groups continued to receive other therapies required to manage their condition. Participants, study staff, and investigators were masked to the study assignment. The primary outcome was the 7-point WHO ordinal scale for clinical status at day 29 after random assignment. The intention-to-treat population included all patients who were randomly assigned and met the enrolment criteria. The safety population included all participants who received at least one dose of study medication. This study was registered with the ISRCTN registry, ISRCTN30564012. Findings Between June 5, 2020, and Jan 25, 2021, 406 patients were randomly assigned to brensocatib or placebo; 192 (47·3%) to the brensocatib group and 214 (52·7%) to the placebo group. Two participants were excluded after being randomly assigned in the brensocatib group (214 patients included in the placebo group and 190 included in the brensocatib group in the intention-to-treat population). Primary outcome data was unavailable for six patients (three in the brensocatib group and three in the placebo group). Patients in the brensocatib group had worse clinical status at day 29 after being randomly assigned than those in the placebo group (adjusted odds ratio 0·72 [95% CI 0·57–0·92]). Prespecified subgroup analyses of the primary outcome supported the primary results. 185 participants reported at least one adverse event; 99 (46%) in the placebo group and 86 (45%) in the brensocatib group. The most common adverse events were gastrointestinal disorders and infections. One death in the placebo group was judged as possibly related to study drug. Interpretation Brensocatib treatment did not improve clinical status at day 29 in patients hospitalised with COVID-19

Apprentissage de représentations auto-supervisé à partir de signaux d'électroencéphalographie

International audienceThe supervised learning paradigm is limited by the cost - and sometimes the impracticality - of data collection and labeling in multiple domains. Self-supervised learning, a paradigm which exploits the structure of unlabeled data to create learning problems that can be solved with standard supervised approaches, has shown great promise as a pretraining or feature learning approach in fields like computer vision and time series processing. In this work, we present self-supervision strategies that can be used to learn informative representations from multivariate time series. One successful approach relies on predicting whether time windows are sampled from the same temporal context or not. As demonstrated on a clinically relevant task (sleep scoring) and with two electroencephalography datasets, our approach outperforms a purely supervised approach in low data regimes, while capturing important physiological information without any access to labels.Le paradigme de l’apprentissage supervisé est limité par le coût - et parfois l’impraticabilité - de la collecte de données et de l’étiquetage dans de multiples domaines. L'apprentissage auto-supervisé, un paradigme qui exploite la structure de données non étiquetées pour créer des problèmes d'apprentissage qui peuvent être résolus avec des approches supervisées standard, s'est révélé très prometteur en tant qu'approche de pré-entraînement ou d'apprentissage de traits caractéristiques dans des domaines tels que la vision par ordinateur et le traitement de séries temporelles. Dans ce travail, nous présentons des stratégies d'auto-supervision pouvant être utilisées pour apprendre des représentations informatives à partir de séries temporelles multivariées. Une approche fructueuse consiste à prédire si des fenêtres temporelles sont échantillonnées dans le même contexte temporel ou non. Comme le démontre une tâche cliniquement pertinente (classification des stades du sommeil) et avec deux jeux de données d'électroencéphalographie, notre approche surpasse une approche purement supervisée dans des régimes de données faibles, tout en capturant des informations physiologiques importantes sans accès aux étiquettes