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Septins possess a conserved guanine nucleotide-binding (G) domain that participates in the stabilization of organized hetero-oligomeric complexes which assemble into filaments, rings and network-like structures. The fruit fly, Drosophila melanogaster, has five such septin genes encoding Sep1, Sep2, Sep4, Sep5 and Pnut. Here, we report the crystal structure of the heterodimer formed between the G-domains of Sep1 and Sep2, the first from an insect to be described to date. A G-interface stabilizes the dimer (in agreement with the expected arrangement for the Drosophila hexameric particle) and this bears significant resemblance to its human counterparts, even down to the level of individual amino acid interactions. On the other hand, a model for the G-interface formed between the two copies of Pnut which occupy the centre of the hexamer, shows important structural differences, including the loss of a highly favourable bifurcated salt-bridge network. Whereas wild-type Pnut purifies as a monomer, the reintroduction of the salt-bridge network results in stabilizing the dimeric interface in solution as shown by size exclusion chromatography and thermal stability measurements. Adaptive steered molecular dynamics reveals an unzipping mechanism for dimer dissociation which initiates at a point of electrostatic repulsion within the switch II region. Overall, the data contribute to a better understanding of the molecular interactions involved in septin assembly/disassembly.

Objectives Emerging evidence of dysregulation of the myeloid cell compartment urges investigations on neutrophil characteristics in coronavirus disease 2019 (COVID‐19). We isolated neutrophils from the blood of COVID‐19 patients receiving general ward care and from patients hospitalised at intensive care units (ICUs) to explore the kinetics of circulating neutrophils and factors important for neutrophil migration and activation. Methods Multicolour flow cytometry was exploited for the analysis of neutrophil differentiation and activation markers. Multiplex and ELISA technologies were used for the quantification of protease, protease inhibitor, chemokine and cytokine concentrations in plasma. Neutrophil polarisation responses were evaluated microscopically. Gelatinolytic and metalloproteinase activity in plasma was determined using a fluorogenic substrate. Co‐culturing healthy donor neutrophils with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) allowed us to investigate viral replication in neutrophils. Results Upon ICU admission, patients displayed high plasma concentrations of granulocyte–colony‐stimulating factor (G‐CSF) and the chemokine CXCL8, accompanied by emergency myelopoiesis as illustrated by high levels of circulating CD10−, immature neutrophils with reduced CXCR2 and C5aR expression. Neutrophil elastase and non‐metalloproteinase‐derived gelatinolytic activity were increased in plasma from ICU patients. Significantly higher levels of circulating tissue inhibitor of metalloproteinase 1 (TIMP‐1) in patients at ICU admission yielded decreased total MMP proteolytic activity in blood. COVID‐19 neutrophils were hyper‐responsive to CXCL8 and CXCL12 in shape change assays. Finally, SARS‐CoV‐2 failed to replicate inside human neutrophils. Conclusion Our study provides detailed insights into the kinetics of neutrophil phenotype and function in severe COVID‐19 patients, and supports the concept of an increased neutrophil activation state in the circulation., In this study, we found that patients suffering from severe COVID‐19 presented with immature, activated blood neutrophils and were characterized by elevated plasma levels of G‐CSF and CXCL8 that disappeared towards ICU discharge. Elevated neutrophil‐derived proteases in plasma of ICU patients were associated with increased non‐metalloproteinase‐derived gelatinolytic activity but decreased total MMP proteolytic activity. SARS‐CoV‐2 failed to replicate inside human neutrophils, suggesting that changes observed in neutrophils from patients with COVID‐19 are indirect consequences of SARS‐CoV‐2 infection in vivo.

Cerebral malaria (CM) is a multifactorial syndrome involving an exacerbated proinflammatory status, endothelial cell activation, coagulopathy, hypoxia, and accumulation of leukocytes and parasites in the brain microvasculature. Despite significant improvements in malaria control, 15% of mortality is still observed in CM cases, and 25% of survivors develop neurologic sequelae for life-even after appropriate antimalarial therapy. A treatment that ameliorates CM clinical signs, resulting in complete healing, is urgently needed. Previously, we showed a hyperbaric oxygen (HBO)-protective effect against experimental CM. Here, we provide molecular evidence that HBO targets brain endothelial cells by decreasing their activation and inhibits parasite and leukocyte accumulation, thus improving cerebral microcirculatory blood flow. HBO treatment increased the expression of aryl hydrocarbon receptor over hypoxia-inducible factor 1-α (HIF-1α), an oxygen-sensitive cytosolic receptor, along with decreased indoleamine 2,3-dioxygenase 1 expression and kynurenine levels. Moreover, ablation of HIF-1α expression in endothelial cells in mice conferred protection against CM and improved survival. We propose that HBO should be pursued as an adjunctive therapy in CM patients to prolong survival and diminish deleterious proinflammatory reaction. Furthermore, our data support the use of HBO in therapeutic strategies to improve outcomes of non-CM disorders affecting the brain.-Bastos, M. F., Kayano, A. C. A. V., Silva-Filho, J. L., Dos-Santos, J. C. K., Judice, C., Blanco, Y. C., Shryock, N., Sercundes, M. K., Ortolan, L. S., Francelin, C., Leite, J. A., Oliveira, R., Elias, R. M., Câmara, N. O. S., Lopes, S. C. P., Albrecht, L., Farias, A. S., Vicente, C. P., Werneck, C. C., Giorgio, S., Verinaud, L., Epiphanio, S., Marinho, C. R. F., Lalwani, P., Amino, R., Aliberti, J., Costa, F. T. M. Inhibition of hypoxia-associated response and kynurenine production in response to hyperbaric oxygen as mechanisms involved in protection against experimental cerebral malaria.

Reversible cerebral vasoconstriction syndrome (RCVS) is a clinical-radiological syndrome characterised by severe thunderclap headaches with or without other neurological symptoms and multifocal constriction of cerebral arteries that usually resolves spontaneously within 3 months. Most patients recover completely, but up to 10% have a permanent neurological disability and some even die. Previously RCVS has been described in many clinical contexts and under different names with the term RCVS first being suggested in 2007 to unify the group. The condition may be spontaneous, but in up to 60% of cases it is secondary to another cause, including vasoactive substances (medications and illicit drugs), blood products and the post-partum state. It is believed to have a similar pathophysiological mechanism to the posterior reversible encephalopathy syndrome (PRES), and both can occur in similar clinical contexts and are frequently associated. Treatment options include calcium channel antagonists. RCVS occurs in a broad range of clinical situations making it an increasingly recognised condition about which doctors in various specialties need to be aware.

Background Multiple sclerosis (MS) is an autoimmune and neurodegenerative disease that affects young adults. It is characterized by generating a chronic demyelinating autoimmune inflammation in the central nervous system. An experimental model for studying MS is the experimental autoimmune encephalomyelitis (EAE), induced by immunization with antigenic proteins from myelin. Aims The present study investigated the evolution of EAE in pregabalin treated animals up to the remission phase. Methods and results The results demonstrated a delay in the onset of the disease with statistical differences at the 10th and the 16th day after immunization. Additionally, the walking track test (CatWalk) was used to evaluate different parameters related to motor function. Although no difference between groups was obtained for the foot print pressure, the regularity index was improved post treatment, indicating a better motor coordination. The immunohistochemical analysis of putative synapse preservation and glial reactivity revealed that pregabalin treatment improved the overall morphology of the spinal cord. A preservation of circuits was depicted and the glial reaction was downregulated during the course of the disease. qRT-PCR data did not show immunomodulatory effects of pregabalin, indicating that the positive effects were restricted to the CNS environment. Conclusions Overall, the present data indicate that pregabalin is efficient for reducing the seriousness of EAE, delaying its course as well as reducing synaptic loss and astroglial reaction.

Multiple sclerosis, which is the most common cause of chronic neurological disability in young adults, is an inflammatory, demyelinating, and neurodegenerative disease of the CNS, which leads to the formation of multiple foci of demyelinated lesions in the white matter. The diagnosis is based currently on magnetic resonance image and evidence of dissemination in time and space. However, this could be facilitated if biomarkers were available to rule out other disorders with similar symptoms as well as to avoid cerebrospinal fluid analysis, which requires an invasive collection. Additionally, the molecular mechanisms of the disease are not completely elucidated, especially those related to the neurodegenerative aspects of the disease. The identification of biomarker candidates and molecular mechanisms of multiple sclerosis may be approached by proteomics. In the last 10 years, proteomic techniques have been applied in different biological samples (CNS tissue, cerebrospinal fluid, and blood) from multiple sclerosis patients and in its experimental model. In this review, we summarize these data, presenting their value to the current knowledge of the disease mechanisms, as well as their importance in identifying biomarkers or treatment targets.

Despite the evolution of treatments in the past decade, acute inflammatory autoimmune diseases of the peripheral nervous system are still a concern due to their considerable morbidity and mortality [1]. Guillain-Barr e syndrome (GBS) is an acute inflammatory disorder. The study of experimental autoimmune neuritis (EAN), the experimental model of GBS, has provided most of the knowledge regarding GBS disease mechanisms. Inflammatory lesions are primarily located in the sciatic nerves and the cauda equina of EAN-affected Lewis rats [2]. Lesions are characterized by an accumulation of inflammatory cells, primarily T cells, and macrophages. The inflammatory response during EAN is characterized mainly by the migration of neuritogenic cells into the peripheral nerves and by the production and secretion of proinflammatory cytokines, such as IFNc, TNFa, IL-6, and IL-17 [3]. During the last years, hematopoietic factors, such as erythropoietin, granulocyte–macrophage colony-stimulating factor and granulocyte–colony-stimulating factor (G-CSF), have been successfully used to modify experimental autoimmune diseases [4,5]. Moreover, G-CSF has an important and strong tolerogenic function. This cytokine recruits immature dendritic cells (DCs), which induce tolerance through the enhancement of regulatory T cells [5]. In this study, we investigated the effects of short-term G-CSF treatment on the evolution of EAN. EAN was induced using the neuritogenic peptide P253-78 as previously described [6]. The clinical signs of EAN were significantly reduced by the in vivo administration of G-CSF in a short-term treatment regimen (Figure 1A). The development of EAN is characterized by the sensitization and activation of neuritogenic T cells in the peripheral immune organs. These cells migrate into peripheral nerves and release inflammatory mediators, which may contribute directly or indirectly to the destruction of the myelin sheath. We observed a significant reduction in the specific proliferative response of T cells from Lewis rats with EAN treated with G-CSF compared with the cells from the control animals (Figure 1B). Moreover, G-CSF treatment reduced the mononuclear cell infiltration into the sciatic nerve (Figure 1C). The EAN autoaggressive response is characterized by the expression and release of Th1 and/or Th17 cytokines. Therefore, we evaluated the expression, by real-time PCR (Figure S1), of Th1 and Th17 cytokines and transcription factors, in the lymph nodes 10 days after immunization, prior to the migration of the neuritogenic cells from the periphery to the target tissue. We observed a consistent downregulation in the expression of the Th1 (T-bet) and Th17 (RORa and RORct) transcription factors in the G-CSFtreated group compared with control group (Figure 1D). Corroborating the changes in the transcription factors expression profile, the expression of proinflammatory cytokines (IFNc, IL-17A, IL17E, and IL-6) was reduced in the G-CSF-treated group compared with the control group. G-CSF treatment also led to an increase in the expression of anti-inflammatory cytokines, such as IL-10 and

The induction of autoimmune encephalomyelitis (EAE) in Lewis rats results in a period of exacerbation followed by complete recovery. Therefore, this model is widely used for studying the evolution of multiple sclerosis. In the present investigation, differentially expressed proteins in the spinal cord of Lewis rats during the evolution of EAE were assessed using the combination of 2DE and MALDI-TOF MS. The majority of the differentially expressed proteins were identified during the acute phase of EAE, in relation to naïve control animals. On the other hand, recovered rats presented a similar protein expression pattern in comparison with the naïve ones. This observation can be explained, at least in part, by the intense catabolism existent in acute phase due to nervous tissue damage. In recovered rats, we have described the upregulation of proteins that are apparently involved in the recovery of damaged tissue, such as light and medium neurofilaments, glial fibrillary acidic protein, tubulins subunits, and quaking protein. These proteins are involved mainly in cell growth, myelination, and remyelination as well as in astrocyte and oligodendrocyte maturation. The present study has demonstrated that the inflammatory response, characterized by an increase of the proliferative response and infiltration of autoreactive T lymphocytes in the central nervous system, occurs simultaneously with neurodegeneration.

Objective Movement disorders are chronic illnesses that can lead to functional impairment and psychological distress. This study examined the relations between functional impairment, depression, and anxiety in individuals with movement disorders, and whether these associations were mediated by feelings of self-perceived burden. Method This cross-sectional study sampled individuals (57 males and 57 females; mean age of 62) with chronic movement disorders from a movement disorders clinic. Patients completed measures of depression, anxiety, functional impairment, and self-perceived burden. Results Functional impairment was associated with depression, but not anxiety, and was mediated by self-perceived burden for individuals with chronic movement disorders. Conclusions Self-perceived burden may have an important role relative to individuals’ adaptation to chronic illness with implications for future interventions.

Objectives.— To review conjectured modes of action of migraine triggers and to present a new hypothesis about them. Background.— Migraine attacks are initiated in many migraineurs by a variety of “triggers,” although in some patients no external trigger can be identified. Many triggers provoke attacks with such a short latency that only some kind of neural mechanism can explain the triggering. Results.— We present here a hypothesis that the pain of migraine has its ultimate origin in the cortex, but that the immediate generator is in the brainstem. Our hypothesis is that most migraines have triggers that produce excitation of cortical neurons and that this directly causes withdrawal of descending sensory inhibition originating in the brainstem. A wide range of evidence from the literature that cortical activation induced by a number of different mechanisms often produces headache is presented to support this notion. Several nuclei in the brainstem appear to participate in the selective control of trigeminovascular sensation through descending inhibitory mechanisms that arise in the cortex. In this review we focus on 2 of them, the periaqueductal gray matter and nucleus raphe magnus. Our own past results and those of others show that this inhibition is specific for craniovascular sensation and involves the neurotransmitter 5-hydroxytryptamine. Finally, we summarize our own recent experiments, which show that cortical activation by migraine triggers (including cortical spreading depression) inhibits neuronal discharge in the brainstem and facilitates trigeminovascular sensation. Conclusion.— If the hypothesis can be proven and the neurotransmitters involved in the hypothetical trigger pathway can be identified, it may be possible to develop novel migraine preventative therapies.

Multiple sclerosis is an idiopathic demyelinating disease of the CNS. Despite being extensively studied during the last decades, many molecular aspects of the disease are still to be elucidated. Moreover, biomarkers for treatment and early diagnosis are major issues to be tackled. In this edition of Kroksveen et al. (Proteomics 2015, 15, 3361-3369) present biomarker candidates for the early detection of multiple sclerosis. Despite the need for validation in larger sets of samples, this dataset contributes to resolve open questions associated to multiple sclerosis.

The effect of epidermal growth factor (EGF) and insulin on DNA, RNA, and cytoskeletal protein labeling in primary rat astroglial cell cultures was investigated. Cultures were grown for 15–30 days in vitro in 10% fetal calf serum (FCS)-supplemented medium and then maintained in serum-free basal medium (DMEM) supplemented with fatty acid-free bovine serum albumin (BSA) for a starvation period of 24 hr before the addition of factors. The effect of factors was tested at different times (4, 10, 22, and 28 hr). At each time, [methyl-3H]thymidine or [5, 6 -3H]uridine was added to the control and treated cells; the incubation time after the addition of labeled precursors was 2 hr at 37°C. The results obtained indicated that the addition of EGF or FCS significantly stimulated [methyl-3H]thymidine incorporation into DNA, reaching the maximum effect after 22 hr. EGF alone significantly stimulated [3H]uridine incorporation into RNA, and this effect was already maximum at 4 hr and remained constant up to 22 hr. The addition of insulin alone caused a slight increase in nucleic acid labeling for short times (4–10 hr). In contrast with EGF, no detectable stimulation of incorporation of labeled precursors after insulin treatment for 22 hr was observed. On the other hand, the addition of insulin in the presence of EGF induced an increase of the values observed with EGF alone on macromolecular synthesis at all the times studied. Furthermore, a decrease in cell number was observed in confluent cultures maintained for 1 week in medium containing DMEM + BSA in comparison to serum-supplemented (DMEM + BSA + FCS) cultures. The addition of EGF to DMEM + BSA significantly increased cell number, while addition of insulin had no effect. The highest values for cell number were observed when insulin and transferrin were added together with EGF. Moreover, EGF treatment in the presence of serum significantly increased the incorporation of labeled amino acids into vimentin, glial fibrillary acidic protein, and actin.