Human malarial disease: a consequence of inflammatory cytokine release

Malaria causes an acute systemic human disease that bears many similarities, both clinically and mechanistically, to those caused by bacteria, rickettsia, and viruses. Over the past few decades, a literature has emerged that argues for most of the pathology seen in all of these infectious diseases being explained by activation of the inflammatory system, with the balance between the pro and anti-inflammatory cytokines being tipped towards the onset of systemic inflammation. Although not often expressed in energy terms, there is, when reduced to biochemical essentials, wide agreement that infection with falciparum malaria is often fatal because mitochondria are unable to generate enough ATP to maintain normal cellular function. Most, however, would contend that this largely occurs because sequestered parasitized red cells prevent sufficient oxygen getting to where it is needed. This review considers the evidence that an equally or more important way ATP deficency arises in malaria, as well as these other infectious diseases, is an inability of mitochondria, through the effects of inflammatory cytokines on their function, to utilise available oxygen. This activity of these cytokines, plus their capacity to control the pathways through which oxygen supply to mitochondria are restricted (particularly through directing sequestration and driving anaemia), combine to make falciparum malaria primarily an inflammatory cytokine-driven disease

SARS-CoV-2 Receptor ACE2 Is an Interferon-Stimulated Gene in Human Airway Epithelial Cells and Is Detected in Specific Cell Subsets across Tissues.

There is pressing urgency to understand the pathogenesis of the severe acute respiratory syndrome coronavirus clade 2 (SARS-CoV-2), which causes the disease COVID-19. SARS-CoV-2 spike (S) protein binds angiotensin-converting enzyme 2 (ACE2), and in concert with host proteases, principally transmembrane serine protease 2 (TMPRSS2), promotes cellular entry. The cell subsets targeted by SARS-CoV-2 in host tissues and the factors that regulate ACE2 expression remain unknown. Here, we leverage human, non-human primate, and mouse single-cell RNA-sequencing (scRNA-seq) datasets across health and disease to uncover putative targets of SARS-CoV-2 among tissue-resident cell subsets. We identify ACE2 and TMPRSS2 co-expressing cells within lung type II pneumocytes, ileal absorptive enterocytes, and nasal goblet secretory cells. Strikingly, we discovered that ACE2 is a human interferon-stimulated gene (ISG) in vitro using airway epithelial cells and extend our findings to in vivo viral infections. Our data suggest that SARS-CoV-2 could exploit species-specific interferon-driven upregulation of ACE2, a tissue-protective mediator during lung injury, to enhance infection

Trypanosoma cruzi trans-sialidase in complex with a neutralizing antibody: Structure/function studies towards the rational design of inhibitors

Trans-sialidase (TS), a virulence factor from Trypanosoma cruzi, is an enzyme playing key roles in the biology of this protozoan parasite. Absent from the mammalian host, it constitutes a potential target for the development of novel chemotherapeutic drugs, an urgent need to combat Chagas' disease. TS is involved in host cell invasion and parasite survival in the bloodstream. However, TS is also actively shed by the parasite to the bloodstream, inducing systemic effects readily detected during the acute phase of the disease, in particular, hematological alterations and triggering of immune cells apoptosis, until specific neutralizing antibodies are elicited. These antibodies constitute the only known submicromolar inhibitor of TS's catalytic activity. We now report the identification and detailed characterization of a neutralizing mouse monoclonal antibody (mAb 13G9), recognizing T. cruzi TS with high specificity and subnanomolar affinity. This mAb displays undetectable association with the T. cruzi superfamily of TS-like proteins or yet with the TS-related enzymes from Trypanosoma brucei or Trypanosoma rangeli. In immunofluorescence assays, mAb 13G9 labeled 100% of the parasites from the infective trypomastigote stage. This mAb also reduces parasite invasion of cultured cells and strongly inhibits parasite surface sialylation. The crystal structure of the mAb 13G9 antigen-binding fragment in complex with the globular region of T. cruzi TS was determined, revealing detailed molecular insights of the inhibition mechanism. Not occluding the enzyme's catalytic site, the antibody performs a subtle action by inhibiting the movement of an assisting tyrosine (Y119), whose mobility is known to play a key role in the trans-glycosidase mechanism. As an example of enzymatic inhibition involving non-catalytic residues that occupy sites distal from the substrate-binding pocket, this first near atomic characterization of a high affinity inhibitory molecule for TS provides a rational framework for novel strategies in the design of chemotherapeutic compounds.Fil: Buschiazzo, Alejandro. Instituto Pasteur de Montevideo; UruguayFil: Muia, Romina Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Larrieux, Nicole. Instituto Pasteur de Montevideo; UruguayFil: Pitcovsky, Tamara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Mucci, Juan Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Campetella, Oscar Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin

Predictors of self-injury cessation and subsequent psychological growth: results of a probability sample survey of students in eight universities and colleges

BACKGROUND: Factors affecting non-suicidal self-injury cessation are poorly understood. The aim of this study was to identify differences between individuals with current and past non-suicidal self-injury (NSSI) in a large probability sample of university students using quantitative and qualitative methods. Predictors of psychological growth related following NSSI cessation were also examined. METHOD: The sample included 836 students who participated in a larger online study of well-being at eight U.S. colleges and who reported current or past history of repeated NSSI. The average age of respondents used in analysis was 21.3 years. They were 78.3 % female and 21.7 % male and were 70.7 % Caucasian, 1.4 % African American/Black, 5.5 % Hispanic, 7.8 % Asian/Asian American and 14.7 % other. Analyses tested differences in demographics, NSSI characteristics (e.g. lifetime frequency, number of NSSI functions, NSSI disclosure), formal help-seeking, psychosocial factors, and mental health and trauma histories. RESULTS: Individuals with current NSSI status were more likely to be female and slightly younger, to report higher NSSI lifetime frequency, more NSSI forms and functions, thinking of themselves as a “self-injurer”, and current psychological distress. Individuals with current NSSI status were less likely to report that self-injury interfered with life, that therapy was useful in stopping, perceiving social support, having a sense of meaning in life, access to more emotion regulation strategies, and life satisfaction. Qualitative data suggested that cessation may be attributable to changes in ability to regulate emotion (62.6 %), self-awareness (38.7 %), and important relationships to others (36.0 %). Psychological growth after stopping NSSI was predicted by more severe NSSI (form and perceived NSSI dependence), having talked about NSSI with others and higher numbers of confidantes, perceived life satisfaction, and a history of suicide action. CONCLUSIONS: These findings add to the still nascent body of literature examining processes related to NSSI cessation. Our results point to the importance of help-seeking and social support, as well as psychosocial processes in stopping NSSI

Educational interventions for general practitioners to identify and manage depression as a suicide risk factor in young people: a systematic review and meta-analysis protocol

BACKGROUND: Suicide is a major public health problem and globally is the second leading cause of death in young adults. Globally, there are 164,000 suicides per year in young people under 25 years. Depression is a strong risk factor for suicide. Evidence shows that 45% of those completing suicide, including young adults, contact their general practitioner rather than a mental health professional in the month before their death. Further evidence indicates that risk factors or early warning signs of suicide in young people go undetected and untreated by general practitioners. Healthcare-based suicide prevention interventions targeted at general practitioners are designed to increase identification of at-risk young people. The rationale of this type of intervention is that early identification and improved clinical management of at-risk individuals will reduce morbidity and mortality. This systematic review will synthesise evidence on the effectiveness of education interventions for general practitioners in identifying and managing depression as a suicide risk factor in young people. METHODS/DESIGN: We shall conduct a systematic review and meta-analysis following the Cochrane Handbook for Systematic Reviews of Interventions guidelines and conform to the reporting guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. Electronic databases will be systematically searched for randomised controlled trials and quasi-experimental studies investigating the effectiveness of interventions for general practitioners in identifying and managing depression as a suicide risk factor in young people in comparison to any other intervention, no intervention, usual care or waiting list. Grey literature will be searched by screening trial registers. Only studies published in English will be included. No date restrictions will be applied. Two authors will independently screen titles and abstracts of potential studies. The primary outcome is identification and management of depression. Secondary outcomes are suicidal ideation, suicide attempts, deliberate self-harm, knowledge of suicide risk factors and suicide-related behaviours, attitudes towards suicide risk and suicide-related behaviours, confidence in dealing with suicide risk factors and suicide-related behaviour. DISCUSSION: Our study will inform the development of future education interventions and provide feasibility and acceptability evidence, to help general practitioners identify and manage suicidal behaviour in young people. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number: CRD42014009110. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/2046-4053-3-145) contains supplementary material, which is available to authorized users