The effect of human cytomegalovirus on neutrophil survival, autophagy, and extracellular traps

Neutrophils provide a rapid first response to invading pathogens and orchestrate the immune response. They are able to employ potent antipathogenic mechanisms such as phagocytosis, reactive oxygen species (ROS) generation, protease release from granules, and formation of neutrophil extracellular traps (NETs). Despite this, certain pathogens have evolved mechanisms to benefit from neutrophil effector functions. Human cytomegalovirus (HCMV) is a clinically important pathogen that infects the majority of the human population. Monocytes are considered the main vehicle of HCMV dissemination throughout the body, but little research has been done on its interaction with neutrophils. The virus encodes a range of immunomodulatory proteins including an IL-8 homologue that acts as a powerful neutrophil chemoattractant. Viral conservation of a protein that recruits neutrophils to the site of HCMV infection suggests that the interaction between neutrophils and HCMV provides an overall advantage to the virus, but little evidence exists so far to suggest this is the case. Here I report that human peripheral blood neutrophils exposed to a clinical strain of HCMV display a profound survival phenotype, as assessed by morphology, phosphatidylserine exposure, cell permeability, and caspase-3/7 activity. This occurs in the absence of viral gene production. Neutrophils also upregulated their release of inflammatory cytokines in response to HCMV, with higher concentrations of IL-6, IL-8, and MIP-1α detected in the secretomes of infected neutrophils. These secretomes induced monocyte chemotaxis and increased monocyte permissivity to HCMV infection, as well as augmented survival in healthy, uninfected neutrophils. These experiments were confirmed with clean HCMV after the discovery of contaminating Mycoplasma spp. in the viral inocula of the initial experiments. Mycoplasma-HCMV coinfection induced an autophagic phenotype in neutrophils, as assessed by Western blotting and qPCR of autophagy-related components. Inhibition of autophagy using 3-MA reversed a profound survival effect. The unintended inclusion of Mycoplasma spp. further led to the serendipitous discovery of yet another pathogenic ability to overcome neutrophil immune functions: contaminating Mycoplasma spp. as well as Mycoplasma pneumoniae profoundly degraded NETs. These extracellular chromatin structures were stimulated using PMA or pyocyanin, and their release was dependent on the generation of ROS: severely ROS-deficient murine bone marrow neutrophils were unable to generate NETs. However, small amounts of ROS were sufficient for NETs generation, as neutrophils from acute respiratory distress syndrome patients, including many that had attenuated ROS-responses, were still capable of NETs generation. The NETs-degradative properties of mycoplasma were confirmed by fluorescence confocal and scanning electron microscopy, as well as spectrophotometry and agarose gel electrophoresis. This study demonstrates that two pervasive pathogens, HCMV and M. pneumoniae, both frequently found in coinfections in clinical contexts, are able to overcome neutrophil antipathogenic mechanisms to potentially enhance pathogen dissemination. These data provide not only a novel example of manipulation of an anti-viral response in a cell not productively infected, but also a novel example of pathogenic NETs degradation. These findings may have implications on our understanding of mycoplasma and HCMV pathogenesis and provide new targets for the generation of therapies.Gates Cambridg

Factors associated with mobile phone usage to access maternal and child healthcare among women of urban slums in Dhaka, Bangladesh: a cross-sectional study.

INTRODUCTION: With the acute shortage of human resources and infrastructure, mobile phones can be a critical tool for accessing health services and strengthening health systems in Bangladesh. Yet, there is a scarcity of evidence on the use of mobile phones in this context for accessing health services. In this study, we sought to explore the current use of mobile phones for accessing maternal and child healthcare and its determinants among recently delivered women in urban slums of Bangladesh. METHODS: The data were collected through interviewing 800 recently delivered women from eight slums of Dhaka city of Bangladesh during May and June 2018. The study followed a cross-sectional design and a two-stage cluster random sampling procedure was followed. A pretested structured questionnaire was employed to collect information. Chi square tests were performed for descriptive analyses and a multilevel binary logistic regression model was executed to explore the determinants of mobile phone usage for accessing maternal and childcare among the participants. RESULTS: Overall, 73.8% of study participants used mobile phones for accessing maternal and child healthcare. After adjusting for potential confounders, participants' age, husband's occupation, sex of household head, women's ownership of mobile phones and household wealth status were found to be significantly associated with higher odds of using mobile phones to access maternal and child healthcare. CONCLUSION: The study highlighted the possibility of implementing large-scale mobile health (mHealth) interventions in slum settlements for accessing maternal and child healthcare and is a sustainable mitigation strategy for the acute health worker crisis in Bangladesh. The findings of this study are particularly crucial for policymakers and practitioners while they revise the health policy to incorporate mHealth interventions as highlighted in the recently initiated Digital Health Strategy of Bangladesh

Phenotype of ARDS alveolar and blood neutrophils

RATIONALE: Acute respiratory distress syndrome is refractory to pharmacological intervention. Inappropriate activation of alveolar neutrophils is believed to underpin this disease's complex pathophysiology, yet these cells have been little studied. OBJECTIVES: To examine the functional and transcriptional profiles of patient blood and alveolar neutrophils compared with healthy volunteer cells, and to define their sensitivity to phosphoinositide 3-kinase inhibition. METHODS: Twenty-three ventilated patients underwent bronchoalveolar lavage. Alveolar and blood neutrophil apoptosis, phagocytosis, and adhesion molecules were quantified by flow cytometry, and oxidase responses were quantified by chemiluminescence. Cytokine and transcriptional profiling were used in multiplex and GeneChip arrays. MEASUREMENTS AND MAIN RESULTS: Patient blood and alveolar neutrophils were distinct from healthy circulating cells, with increased CD11b and reduced CD62L expression, delayed constitutive apoptosis, and primed oxidase responses. Incubating control cells with disease bronchoalveolar lavage recapitulated the aberrant functional phenotype, and this could be reversed by phosphoinositide 3-kinase inhibitors. In contrast, the prosurvival phenotype of patient cells was resistant to phosphoinositide 3-kinase inhibition. RNA transcriptomic analysis revealed modified immune, cytoskeletal, and cell death pathways in patient cells, aligning closely to sepsis and burns datasets but not to phosphoinositide 3-kinase signatures. CONCLUSIONS: Acute respiratory distress syndrome blood and alveolar neutrophils display a distinct primed prosurvival profile and transcriptional signature. The enhanced respiratory burst was phosphoinositide 3-kinase-dependent but delayed apoptosis and the altered transcriptional profile were not. These unexpected findings cast doubt over the utility of phosphoinositide 3-kinase inhibition in acute respiratory distress syndrome and highlight the importance of evaluating novel therapeutic strategies in patient-derived cells.This work was funded by a non-commercial grant from GSK, with additional support from The Wellcome Trust, Papworth Hospital, The British Lung Foundation and the NIHR Cambridge Biomedical Research Centre. DMLS holds a Gates Cambridge Scholarship; CS is in receipt of a Wellcome Trust Early Postdoctoral Research Fellowship for Clinician Scientists [WT101692MA].This is the author accepted manuscript. The final version is available from ATS Journals via http://dx.doi.org/10.1164/rccm.201509-1818O

Identification of LukPQ, a novel, equid-adapted leukocidin of Staphylococcus aureus.

Bicomponent pore-forming leukocidins are a family of potent toxins secreted by Staphylococcus aureus, which target white blood cells preferentially and consist of an S- and an F-component. The S-component recognizes a receptor on the host cell, enabling high-affinity binding to the cell surface, after which the toxins form a pore that penetrates the cell lipid bilayer. Until now, six different leukocidins have been described, some of which are host and cell specific. Here, we identify and characterise a novel S. aureus leukocidin; LukPQ. LukPQ is encoded on a 45 kb prophage (ΦSaeq1) found in six different clonal lineages, almost exclusively in strains cultured from equids. We show that LukPQ is a potent and specific killer of equine neutrophils and identify equine-CXCRA and CXCR2 as its target receptors. Although the S-component (LukP) is highly similar to the S-component of LukED, the species specificity of LukPQ and LukED differs. By forming non-canonical toxin pairs, we identify that the F-component contributes to the observed host tropism of LukPQ, thereby challenging the current paradigm that leukocidin specificity is driven solely by the S-component

Eros is a novel transmembrane protein that controls the phagocyte respiratory burst and is essential for innate immunity

The phagocyte respiratory burst is crucial for innate immunity. The transfer of electrons to oxygen is mediated by a membrane-bound heterodimer, comprising gp91$\textit{phox}$ and p22$\textit{phox}$ subunits. Deficiency of either subunit leads to severe immunodeficiency. We describe Eros (essential for reactive oxygen species), a protein encoded by the previously undefined mouse gene $\textit{bc017643}$, and show that it is essential for host defense via the phagocyte NAPDH oxidase. Eros is required for expression of the NADPH oxidase components, gp91$\textit{phox}$ and p22$\textit{phox}$. Consequently, $\textit{Eros}$-deficient mice quickly succumb to infection. $\textit{Eros}$ also contributes to the formation of neutrophil extracellular traps (NETS) and impacts on the immune response to melanoma metastases. $\textit{Eros}$ is an ortholog of the plant protein Ycf4, which is necessary for expression of proteins of the photosynthetic photosystem 1 complex, itself also an NADPH oxio-reductase. We thus describe the key role of the previously uncharacterized protein Eros in host defense.D.C. Thomas was funded by a Wellcome Trust/CIMR Next Generation Fellowship, a National Institute for Health Research (NIHR) Clinical Lectureship, and a Starter Grant for Clinical Lecturers (Academy of Medical Sciences). K.G.C. Smith was funded by funded by the Medical Research Council (program grant MR/L019027) and is a Wellcome Investigator and a NIHR Senior Investigator. S. Clare and G. Dougan were funded by the Wellcome Trust (grant 098051). The Cambridge Institute for Medical Research is in receipt of a Wellcome Trust Strategic Award (079895). J.C.L is funded by a Wellcome Intermediate Clinical Fellowship 105920/2/14/2

Magnitude and associated factors of unmet need for family planning among rural women in Ethiopia: a multilevel cross-sectional analysis

Objective This study was aimed to assess the magnitude and associated factors of unmet need for family planning among rural women in Ethiopia.Design Cross-sectional study.Setting Ethiopia.Participants Reproductive age group women.Primary outcome Unmet need for family planning.Methods This study drew data from Ethiopian Demographic and Health Survey, which was conducted from 18 January to 27 June 2016. A total of 8327 rural reproductive-aged (15–49 years) women were included. A two-level multivariable logistic regression model was carried out to identify individual and community-level factors associated with unmet need for family planning. Adjusted OR (AOR) with a 95% CI was used to assess the strength of association between independent and dependent variables.Results The overall unmet need for family planning among rural women was 24.08% (95% CI 23.17 to 25.01), of which 14.79% was for spacing and 9.29% for limiting. Number of children (AOR=1.15; 95% CI 1.07 to 1.24) and working status of women (AOR=1.18; 95% CI 1.02 to 1.37) were significantly associated with a higher odds of unmet need for family planning. However, women with primary education (AOR=0.87; 95% CI 0.74 to 0.94), women married at age 18 or later (AOR=0.82; 95% CI 0.70 to 0.96), women from households with high wealth index (AOR=0.77; 95% CI 0.64 to 0.94), women who deem distance to a health facility as not a big problem (AOR=0.85; 95% CI 0.73 to 0.99), women from communities with a high percentage of educated women (AOR=0.73; 95% CI 0.59 to 0.89) and women who live in communities with high media exposure (AOR=0.81, 95% CI 0.68 to 0.98) were significantly associated with a lower odds of unmet needs for family planning.Conclusion Unmet need for family planning among reproductive-aged women in rural Ethiopia was high. Number of children, working status of women, women’s education, age at first marriage, household wealth, distance to a health facility, community women’s education and community media exposure were significantly associated with unmet needs for family planning. Therefore, to reduce unmet need for family planning, public health policymakers should consider both individual and community-level factors when designing FP programmes and emphasis should be given to high-risk populations

Evasion of Neutrophil Extracellular Traps by Respiratory Pathogens.

The release of neutrophil extracellular traps (NETs) is a major immune mechanism intended to capture pathogens. These histone- and protease-coated DNA structures are released by neutrophils in response to a variety of stimuli, including respiratory pathogens, and have been identified in the airways of patients with respiratory infection, cystic fibrosis, acute lung injury, primary graft dysfunction, and chronic obstructive pulmonary disease. NET production has been demonstrated in the lungs of mice infected with Staphylococcus aureus, Klebsiella pneumoniae, and Aspergillus fumigatus. Since the discovery of NETs over a decade ago, evidence that "NET evasion" might act as an immune protection strategy among respiratory pathogens, including group A Streptococcus, Bordetella pertussis, and Haemophilus influenzae, has been growing, with the majority of these studies being published in the past 2 years. Evasion strategies fall into three main categories: inhibition of NET release by down-regulating host inflammatory responses; degradation of NETs using pathogen-derived DNases; and resistance to the microbicidal components of NETs, which involves a variety of mechanisms, including encapsulation. Hence, the evasion of NETs appears to be a widespread strategy to allow pathogen proliferation and dissemination, and is currently a topic of intense research interest. This article outlines the evidence supporting the three main strategies of NET evasion-inhibition, degradation, and resistance-with particular reference to common respiratory pathogens

Exploring Factors Associated with Women’s Willingness to Provide Digital Fingerprints in Accessing Healthcare Services: A Cross-Sectional Study in Urban Slums of Bangladesh

Digital fingerprints are increasingly used for patient care and treatment delivery, health system monitoring and evaluation, and maintaining data integrity during health research. Yet, no evidence exists about the use of fingerprinting technologies in maternal healthcare services in urban slum contexts, globally. The present study aimed to explore the recently delivered women’s willingness to give digital fingerprints to community health workers to access healthcare services in the urban slums of Bangladesh and identify the associated factors. Employing a two-stage cluster random sampling procedure, we chose 458 recently delivered women from eight randomly selected urban slums of Dhaka city, Bangladesh. Chi-square tests were performed for descriptive analyses, and binary logistic regression analyses were performed to explore the factors associated with willingness to provide fingerprints. Overall, 78% of the participants reported that they were willing to provide digital fingerprints if that eased access to healthcare services. After adjusting for potential confounders, the sex of the household head, family type, and household wealth status were significantly associated with the willingness to provide fingerprints to access healthcare services. The study highlighted the potentials of using fingerprints for making healthcare services accessible. Focus is needed for female-headed households, women from poor families, and engaging husbands and in-laws in mobile health programs.Medicine, Faculty ofNon UBCPopulation and Public Health (SPPH), School ofReviewedFacultyResearcherPostdoctoralOthe

Human Cytomegalovirus Delays Neutrophil Apoptosis and Stimulates the Release of a Prosurvival Secretome

Human cytomegalovirus (HCMV) is a major cause of viral disease in the young and the immune-suppressed. At sites of infection, HCMV recruits the neutrophil, a cell with a key role in orchestrating the initial immune response. Herein, we report a profound survival response in human neutrophils exposed to the clinical HCMV isolate Merlin, but not evident with the attenuated strain AD169, through suppression of apoptosis. The initial survival event, which is independent of viral gene expression and involves activation of the ERK/MAPK and NF-κB pathways, is augmented by HCMV-stimulated release of a secretory cytokine profile that further prolongs neutrophil lifespan. As aberrant neutrophil survival contributes to tissue damage, we predict that this may be relevant to the immune pathology of HCMV, and the presence of this effect in clinical HCMV strains and its absence in attenuated strains implies a beneficial effect to the virus in pathogenesis and/or dissemination. In addition, we show that HCMV-exposed neutrophils release factors that enhance monocyte recruitment and drive monocyte differentiation to a HCMV-permissive phenotype in an IL-6-dependent manner, thus providing an ideal vehicle for viral dissemination. This study increases understanding of HCMV–neutrophil interactions, highlighting the potential role of neutrophil recruitment as a virulence mechanism to promote HCMV pathology in the host and influence the dissemination of HCMV infection. Targeting these mechanisms may lead to new antiviral strategies aimed at limiting host damage and inhibiting viral spread