Complement dysregulation is associated with severe COVID-19 illness

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) may manifest as thrombosis, stroke, renal failure, myocardial infarction, and thrombocytopenia, reminiscent of other complement- mediated diseases. Multiple clinical and preclinical studies have implicated complement in the pathogenesis of COVID-19 illness. We previously found that the SARS-CoV-2 spike protein activates the alternative pathway of complement (APC) in vitro through interfering with the function of complement factor H, a key negative regulator of APC. Here, we demonstrated that serum from 58 COVID-19 patients (32 patients with minimal oxygen requirement, 7 on high flow oxygen, 17 requiring mechanical ventilation and 2 deaths) can induce complementmediated cell death in a functional assay (the modified Ham test) and increase membrane attack complex (C5b-9) deposition on the cell surface. A positive modified Ham assay (>20% cell-killing) was present in 41.2% COVID-19 patients requiring intubation (n=7/17) and only 6.3% in COVID-19 patients requiring minimal oxygen support (n=2/32). C5 and factor D inhibition effectively mitigated the complement amplification induced by COVID-19 patient serum. Increased serum factor Bb level was associated with disease severity in COVID-19 patients, suggesting that APC dysregulation plays an important role. Moreover, SARS-CoV-2 spike proteins directly block complement factor H from binding to heparin, which may lead to complement dysregulation on the cell surface. Taken together, our data suggest that complement dysregulation contributes to the pathogenesis of COVID-19 and may be a marker of disease severity

Using C. elegans to decipher the cellular and molecular mechanisms underlying neurodevelopmental disorders

Prova tipográfica (uncorrected proof)Neurodevelopmental disorders such as epilepsy, intellectual disability (ID), and autism spectrum disorders (ASDs) occur in over 2 % of the population, as the result of genetic mutations, environmental factors, or combination of both. In the last years, use of large-scale genomic techniques allowed important advances in the identification of genes/loci associated with these disorders. Nevertheless, following association of novel genes with a given disease, interpretation of findings is often difficult due to lack of information on gene function and effect of a given mutation in the corresponding protein. This brings the need to validate genetic associations from a functional perspective in model systems in a relatively fast but effective manner. In this context, the small nematode, Caenorhabditis elegans, presents a good compromise between the simplicity of cell models and the complexity of rodent nervous systems. In this article, we review the features that make C. elegans a good model for the study of neurodevelopmental diseases. We discuss its nervous system architecture and function as well as the molecular basis of behaviors that seem important in the context of different neurodevelopmental disorders. We review methodologies used to assess memory, learning, and social behavior as well as susceptibility to seizures in this organism. We will also discuss technological progresses applied in C. elegans neurobiology research, such as use of microfluidics and optogenetic tools. Finally, we will present some interesting examples of the functional analysis of genes associated with human neurodevelopmental disorders and how we can move from genes to therapies using this simple model organism.The authors would like to acknowledge Fundação para a Ciência e Tecnologia (FCT) (PTDC/SAU-GMG/112577/2009). AJR and CB are recipients of FCT fellowships: SFRH/BPD/33611/2009 and SFRH/BPD/74452/2010, respectively

Analysis of shared heritability in common disorders of the brain

ience, this issue p. eaap8757 Structured Abstract INTRODUCTION Brain disorders may exhibit shared symptoms and substantial epidemiological comorbidity, inciting debate about their etiologic overlap. However, detailed study of phenotypes with different ages of onset, severity, and presentation poses a considerable challenge. Recently developed heritability methods allow us to accurately measure correlation of genome-wide common variant risk between two phenotypes from pools of different individuals and assess how connected they, or at least their genetic risks, are on the genomic level. We used genome-wide association data for 265,218 patients and 784,643 control participants, as well as 17 phenotypes from a total of 1,191,588 individuals, to quantify the degree of overlap for genetic risk factors of 25 common brain disorders. RATIONALE Over the past century, the classification of brain disorders has evolved to reflect the medical and scientific communities' assessments of the presumed root causes of clinical phenomena such as behavioral change, loss of motor function, or alterations of consciousness. Directly observable phenomena (such as the presence of emboli, protein tangles, or unusual electrical activity patterns) generally define and separate neurological disorders from psychiatric disorders. Understanding the genetic underpinnings and categorical distinctions for brain disorders and related phenotypes may inform the search for their biological mechanisms. RESULTS Common variant risk for psychiatric disorders was shown to correlate significantly, especially among attention deficit hyperactivity disorder (ADHD), bipolar disorder, major depressive disorder (MDD), and schizophrenia. By contrast, neurological disorders appear more distinct from one another and from the psychiatric disorders, except for migraine, which was significantly correlated to ADHD, MDD, and Tourette syndrome. We demonstrate that, in the general population, the personality trait neuroticism is significantly correlated with almost every psychiatric disorder and migraine. We also identify significant genetic sharing between disorders and early life cognitive measures (e.g., years of education and college attainment) in the general population, demonstrating positive correlation with several psychiatric disorders (e.g., anorexia nervosa and bipolar disorder) and negative correlation with several neurological phenotypes (e.g., Alzheimer's disease and ischemic stroke), even though the latter are considered to result from specific processes that occur later in life. Extensive simulations were also performed to inform how statistical power, diagnostic misclassification, and phenotypic heterogeneity influence genetic correlations. CONCLUSION The high degree of genetic correlation among many of the psychiatric disorders adds further evidence that their current clinical boundaries do not reflect distinct underlying pathogenic processes, at least on the genetic level. This suggests a deeply interconnected nature for psychiatric disorders, in contrast to neurological disorders, and underscores the need to refine psychiatric diagnostics. Genetically informed analyses may provide important "scaffolding" to support such restructuring of psychiatric nosology, which likely requires incorporating many levels of information. By contrast, we find limited evidence for widespread common genetic risk sharing among neurological disorders or across neurological and psychiatric disorders. We show that both psychiatric and neurological disorders have robust correlations with cognitive and personality measures. Further study is needed to evaluate whether overlapping genetic contributions to psychiatric pathology may influence treatment choices. Ultimately, such developments may pave the way toward reduced heterogeneity and improved diagnosis and treatment of psychiatric disorders

SARS‐CoV‐2 infection results in upregulation of Plasminogen Activator Inhibitor‐1 and Neuroserpin in the lungs, and an increase in fibrinolysis inhibitors associated with disease severity

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection results in coagulation activation although it is usually not associated with consumption coagulopathy. D‐dimers are also commonly elevated despite systemic hypofibrinolysis. To understand these unusual features of coronavirus disease 2019 (COVID‐19) coagulopathy, 64 adult patients with SARS‐CoV‐2 infection (36 moderate and 28 severe) and 16 controls were studied. We evaluated the repertoire of plasma protease inhibitors (Serpins, Kunitz, Kazal, Cystatin‐like) targeting the fibrinolytic system: Plasminogen Activator Inhibitor‐1 (PAI‐1), Tissue Plasminogen Activator/Plasminogen Activator Inhibitor‐1 complex (t‐PA/PAI‐1), α‐2‐Antiplasmin, Plasmin‐α2‐Antiplasmin Complex, Thrombin‐activatable Fibrinolysis Inhibitor (TAFI)/TAFIa, Protease Nexin‐1 (PN‐1), and Neuroserpin (the main t‐PA inhibitor of the central nervous system). Inhibitors of the common (Antithrombin, Thrombin‐antithrombin complex, Protein Z [PZ]/PZ inhibitor, Heparin Cofactor II, and α2‐Macroglobulin), Protein C ([PC], Protein C inhibitor, and Protein S), contact (Kallistatin, Protease Nexin‐2/Amyloid Beta Precursor Protein, and α‐1‐Antitrypsin), and complement (C1‐Inhibitor) pathways, in addition to Factor XIII, Histidine‐rich glycoprotein (HRG) and Vaspin were also investigated by enzyme‐linked immunosorbent assay. The association of these markers with disease severity was evaluated by logistic regression. Pulmonary expression of PAI‐1 and Neuroserpin in the lungs from eight post‐mortem cases was assessed by immunohistochemistry. Results show that six patients (10%) developed thrombotic events, and mortality was 11%. There was no significant reduction in plasma anticoagulants, in keeping with a compensated state. However, an increase in fibrinolysis inhibitors (PAI‐1, Neuroserpin, PN‐1, PAP, and t‐PA/PAI‐1) was consistently observed, while HRG was reduced. Furthermore, these markers were associated with moderate and/or severe disease. Notably, immunostains demonstrated overexpression of PAI‐1 in epithelial cells, macrophages, and endothelial cells of fatal COVID‐19, while Neuroserpin was found in intraalveolar macrophages only. These results imply that the lungs in SARS‐CoV‐2 infection provide anti‐fibrinolytic activity resulting in a shift toward a local and systemic hypofibrinolytic state predisposing to (immuno)thrombosis, often in a background of compensated disseminated intravascular coagulation

Silent cerebral infarction during immune TTP remission: prevalence, predictors, and impact on cognition.

Immune thrombotic thrombocytopenic purpura (iTTP) survivors have increased risk of cardiovascular disease, including strokes, and report persistent cognitive difficulties during remission. We conducted this prospective study involving iTTP survivors during clinical remission to determine the prevalence of silent cerebral infarction (SCI), defined as magnetic resonance imaging (MRI) evidence of brain infarction without corresponding overt neurodeficits. We also tested the hypothesis that SCI is associated with cognitive impairment, assessed using the National Institutes of Health ToolBox Cognition Battery. For cognitive assessments, we used fully corrected T scores adjusted for age, sex, race, and education. Based on the diagnostic and statistical manual 5 criteria, we defined mild and major cognitive impairment as T scores with a 1 or 2 standard deviation (SD) and \u3e2 SD below the mean on at least 1 test, respectively. Forty-two patients were enrolled, with 36 completing MRIs. SCI was present in 50% of the patients (18), of which 8 (44.4%) had prior overt stroke including during acute iTTP. Patients with SCI had higher rates of cognitive impairment (66.7% vs 27.7%; P = .026), including major cognitive impairment (50% vs 5.6%; P = .010). In separate logistic regression models, SCI was associated with any (mild or major) cognitive impairment (odds ratio [OR] 10.5 [95% confidence interval (95% CI), 1.45-76.63]; P = .020) and major cognitive impairment (OR 7.98 [95% CI, 1.11-57.27]; P = .039) after adjusting for history of stroke and Beck depression inventory scores. MRI evidence of brain infarction is common in iTTP survivors; the strong association of SCI with impaired cognition suggests that these silent infarcts are neither silent nor innocuous

Characterization of an antennal carboxylesterase from the pest moth Spodoptera littoralis degrading a host plant odorant.

Background: Carboxyl/cholinesterases (CCEs) are highly diversified in insects. These enzymes have a broad range of proposed functions, in neuro/developmental processes, dietary detoxification, insecticide resistance or hormone/pheromone degradation. As few functional data are available on purified or recombinant CCEs, the physiological role of most of these enzymes is unknown. Concerning their role in olfaction, only two CCEs able to metabolize sex pheromones have been functionally characterized in insects. These enzymes are only expressed in the male antennae, and secreted into the lumen of the pheromone-sensitive sensilla. CCEs able to hydrolyze other odorants than sex pheromones, such as plant volatiles, have not been identified. Methodology: In Spodoptera littoralis, a major crop pest, a diversity of antennal CCEs has been previously identified. We have employed here a combination of molecular biology, biochemistry and electrophysiology approaches to functionally characterize an intracellular CCE, SlCXE10, whose predominant expression in the olfactory sensilla suggested a role in olfaction. A recombinant protein was produced using the baculovirus system and we tested its catabolic properties towards a plant volatile and the sex pheromone components. Conclusion: We showed that SlCXE10 could efficiently hydrolyze a green leaf volatile and to a lesser extent the sex pheromone components. The transcript level in male antennae was also strongly induced by exposure to this plant odorant. In antennae, SlCXE10 expression was associated with sensilla responding to the sex pheromones and to plant odours. These results suggest that a CCE-based intracellular metabolism of odorants could occur in insect antennae, in addition to the extracellular metabolism occurring within the sensillar lumen. This is the first functional characterization of an Odorant- Degrading Enzyme active towards a host plant volatile

An interleukin-17–mediated paracrine network promotes tumor resistance to anti-angiogenic therapy

Although angiogenesis inhibitors have provided substantial clinical benefit as cancer therapeutics, their use is limited by resistance to their therapeutic effects. While ample evidence indicates that such resistance can be influenced by the tumor microenvironment, the underlying mechanisms remain incompletely understood. Here, we have uncovered a paracrine signaling network between the adaptive and innate immune systems that is associated with resistance in multiple tumor models: lymphoma, lung and colon. Tumor-infiltrating T helper type 17 (T(H)17) cells and interleukin-17 (IL-17) induced the expression of granulocyte colony-stimulating factor (G-CSF) through nuclear factor κB (NF-κB) and extracellular-related kinase (ERK) signaling, leading to immature myeloid-cell mobilization and recruitment into the tumor microenvironment. The occurrence of T(H)17 cells and Bv8-positive granulocytes was also observed in clinical tumor specimens. Tumors resistant to treatment with antibodies to VEGF were rendered sensitive in IL-17 receptor (IL-17R)-knockout hosts deficient in T(H)17 effector function. Furthermore, pharmacological blockade of T(H)17 cell function sensitized resistant tumors to therapy with antibodies to VEGF. These findings indicate that IL-17 promotes tumor resistance to VEGF inhibition, suggesting that immunomodulatory strategies could improve the efficacy of anti-angiogenic therapy