Summary As part of the innate immune response, neutrophils are at the forefront of defence against infection, resolution of inflammation and wound healing. They are the most abundant leucocytes in the peripheral blood, have a short lifespan and an estimated turnover of 1010 to 1011 cells per day. Neutrophils efficiently clear microbial infections by phagocytosis and by oxygen‐dependent and oxygen‐independent mechanisms. In 2004, a new neutrophil anti‐microbial mechanism was described, the release of neutrophil extracellular traps (NETs) composed of DNA, histones and anti‐microbial peptides. Several microorganisms, bacterial products, as well as pharmacological stimuli such as PMA, were shown to induce NETs. Neutrophils contain relatively few mitochondria, and derive most of their energy from glycolysis. In this scenario we aimed to analyse some of the metabolic requirements for NET formation. Here it is shown that NETs formation is strictly dependent on glucose and to a lesser extent on glutamine, that Glut‐1, glucose uptake, and glycolysis rate increase upon PMA stimulation, and that NET formation is inhibited by the glycolysis inhibitor, 2‐deoxy‐glucose, and to a lesser extent by the ATP synthase inhibitor oligomycin. Moreover, when neutrophils were exposed to PMA in glucose‐free medium for 3 hr, they lost their characteristic polymorphic nuclei but did not release NETs. However, if glucose (but not pyruvate) was added at this time, NET release took place within minutes, suggesting that NET formation could be metabolically divided into two phases; the first, independent from exogenous glucose (chromatin decondensation) and, the second (NET release), strictly dependent on exogenous glucose and glycolysis.

Objectives: Neutrophils play an important role in the control of pathogens through several mechanisms, including phagocytosis and the formation of neutrophil extracellular traps (NETs). The latter consists of DNA as a backbone with embedded antimicrobial peptides, histones, and proteases, providing a matrix to entrap and in some cases to kill microbes. Some metabolic requirements for NET formation have recently been described. The virus-induced formation of NETs and the role of these traps in viral infections remain scarcely reported. Here, we analyzed whether dengue virus serotype-2 (DENV-2) induces NET formation and the DENV-2 effect on phorbol myristate acetate (PMA)-induced NETs. Methods: Peripheral blood-derived neutrophils were exposed in vitro to DENV-2 or exposed to DENV-2 and then stimulated with PMA. NET formation was assessed by fluorescence microscopy. Cell membrane Glut-1, glucose uptake, and reactive oxygen species (ROS) production were assessed. Results: DENV-2 does not induce the formation of NETs. Moreover, DENV-2 inhibits PMA-induced formation of NETs by about 80%. This effect is not related to the production of ROS. The mechanism seemingly accountable for this inhibitory effect is the DENV-2-mediated inhibition of PMA-induced glucose uptake by neutrophils. Conclusion: Our results suggest that DENV-2 inhibits glucose uptake as a metabolism-based way to avoid the formation of NETs.

Background: The Mediterranean Diet (MD) has been linked to a reduced risk of developing degenerative diseases, including atherosclerosis, heart stroke, diabetes, arthritis and cancer. However, only a few scientific investigations have attempted to validate this impression. The ingredients of the MD include significant amounts of omega (ω3, ω6, and ω9) unsaturated fatty acids (UFAs). A few studies of these UFAs in the prevention or treatment of arthritis have yielded controversial results, but a general belief regarding their beneficial effects has prevailed. Objective: To investigate the effects of three relevant UFAs, namely Docosahexaenoic Acid (DHA), Arachidonic Acid (AA), and Oleic Acid (OA) (ω3, ω6, and ω9, respectively), in the development of arthritis using a murine model of Collagen-Induced Arthritis (CIA). Methods: DBA-1 mice were immunized with chicken collagen type II (CII) and were subsequently treated with ω-UFAs for 53 days. Dexamethasone (DEXA) was used as a positive anti-inflammatory agent. The effect of the treatments was evaluated through several parameters: inflammation indices, antibody levels, cell proliferation, and histopathological findings. Results and Conclusion: The anti-inflammatory effect of the tested substances was inversely correlated with the histopathological findings: a greater antiinflammatory effect was associated with less articular damage. Oleic acid (ω9) was the most efficient anti-inflammatory UFA, followed by DHA and then AA. DEXA completely inhibited the development of arthritis, whereas the untreated CII-immunized mice developed the most severe articular damage. DBA-1 mice with CII-induced arthritis constitute an adequate model for the study of arthritis and its treatment.

Coatis (Nasua narica) and raccoons (Procyon lotor) potentially play an important role in zoonotic diseases because they may carry pathogens and can transmit them to humans. To date, our understanding of the immune function of these two carnivores is deficient. The aim of this study was to compare the number of leucocyte subtypes and the phagocytic capacity between the coati and the raccoon. Blood samples were collected, and leucocyte subtypes were characterized and counted by flow cytometry and microscopy, respectively. Phagocytosis was analysed by kinetic assay. Differences in leucocytes between these two species were found; the total count of neutrophils was higher in raccoons than in coatis, but lymphocytes and eosinophils were higher in coatis than in raccoons. Antigen reduction was more rapid for the coatis. However, raccoons had a higher efficient endocytic process than coatis. This study provides the basis for understanding the procyonid immune system, which informs conservation, particularly since some procyonids are imperilled.