Identification of RSV Fusion Protein Interaction Domains on the Virus Receptor, Nucleolin.

Nucleolin is an essential cellular receptor to human respiratory syncytial virus (RSV). Pharmacological targeting of the nucleolin RNA binding domain RBD1,2 can inhibit RSV infections in vitro and in vivo; however, the site(s) on RBD1,2 which interact with RSV are not known. We undertook a series of experiments designed to: document RSV-nucleolin co-localization on the surface of polarized MDCK cells using immunogold electron microscopy, to identify domains on nucleolin that physically interact with RSV using biochemical methods and determine their biological effects on RSV infection in vitro, and to carry out structural analysis toward informing future RSV drug development.

A quantitative super-resolution imaging toolbox for diagnosis of motile ciliopathies.

Airway clearance of pathogens and particulates relies on motile cilia. Impaired cilia motility can lead to reduction in lung function, lung transplant, or death in some cases. More than 50 proteins regulating cilia motility are linked to primary ciliary dyskinesia (PCD), a heterogeneous, mainly recessive genetic lung disease.

International consensus guideline for reporting transmission electron microscopy results in the diagnosis of primary ciliary dyskinesia (BEAT PCD TEM Criteria).

Primary ciliary dyskinesia (PCD) is a heterogeneous genetic condition. European and North American diagnostic guidelines recommend transmission electron microscopy (TEM) as one of a combination of tests to confirm a diagnosis. However, there is no definition of what constitutes a defect or consensus on reporting terminology.

Targeting Host Cell Surface Nucleolin for RSV Therapy: Challenges and Opportunities.

Nucleolin (NCL) has been reported as a cellular receptor for the human respiratory syncytial virus (RSV). We studied the effects of re-purposing AS1411, an anti-cancer compound that binds cell surface NCL, as a possible novel strategy for RSV therapy in vitro and in vivo. AS1411 was administered to RSV-infected cultures of non-polarized (HEp-2) and polarized (MDCK) epithelial cells and to virus-infected mice and cotton rats.

Performance of residents using digital images versus glass slides on certification examination in anatomical pathology: a mixed methods pilot study.

Background: It is anticipated that many licensing examination centres for pathology will begin fully digitizing the certification examinations. The objective of our study was to test the feasibility of a fully digital examination and to assess the needs, concerns and expectations of pathology residents in moving from a glass slide-based examination to a fully digital examination.

Methods: We conducted a mixed methods study that compared, after randomization, the performance of senior residents (postgraduate years 4 and 5) in 7 accredited anatomical pathology training programs across Canada on a pathology examination using either glass slides or digital whole-slide scanned images of the slides.

Loss of GD1-positive Lactobacillus correlates with inflammation in human lungs with COPD.

Objectives: The present study assesses the relationship between contents of GD1 (glycerol dehydratase)-positive Lactobacillus, presence of Lactobacillus and the inflammatory response measured in host lung tissue in mild to moderate chronic obstructive pulmonary disease (COPD). We hypothesise that there will be a loss of GD1 producing Lactobacillus with increasing severity of COPD and that GD1 has anti-inflammatory properties.

Setting: Secondary care, 1 participating centre in Vancouver, British Columbia, Canada.

Respiratory syncytial virus receptor expression in the mouse and viral tropism.

Human respiratory syncytial virus (RSV) infects airway epithelium and can cause serious illnesses such as bronchiolitis and pneumonia. With the discovery of cell-surface nucleolin as a fusion receptor for RSV, the question arose as to whether nucleolin could explain RSV tropism in vivo. Here, we report the distribution of cell-surface nucleolin expression in tissues of normal mice and how this distribution of expression relates to what is known about RSV tropism and its clinical manifestations.

A new transcriptional role for matrix metalloproteinase-12 in antiviral immunity.

Interferon-α (IFN-α) is essential for antiviral immunity, but in the absence of matrix metalloproteinase-12 (MMP-12) or IκBα (encoded by NFKBIA) we show that IFN-α is retained in the cytosol of virus-infected cells and is not secreted. Our findings suggest that activated IκBα mediates the export of IFN-α from virus-infected cells and that the inability of cells in Mmp12(-/-) but not wild-type mice to express IκBα and thus export IFN-α makes coxsackievirus type B3 infection lethal and renders respiratory syncytial virus more pathogenic. We show here that after macrophage secretion, MMP-12 is transported into virus-infected cells.

Virus-induced signaling influences endosome trafficking, virus entry, and replication.

Viruses are obligate intracellular pathogens that interact with host cell machinery for enabling entry, replication, and spread. This chapter describes methods for studying the interaction of viruses with host cell signaling pathways and surface receptors during cellular infection, with an emphasis on protein kinases. We also describe how use of immunofluorescence confocal microscopy for imaging virus-host interactions provides a powerful approach for obtaining structural correlations that extend results of immunological and biochemical assays.

Respiratory viral detection and small airway inflammation in lung tissue of patients with stable, mild COPD.

Background: Viral respiratory tract infections are implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). In lung tissue specimens from patients with stable, mild COPD and from control smokers without airflow obstruction, we determined the prevalence and load of nucleic acid from common respiratory viruses and concomitant inflammation of small airways measuring less than 2-mm in diameter.

Methods: Frozen lung tissue obtained from patients with stable, mild COPD (n = 20) and control subjects (n = 20) underwent real-time quantitative PCR (qPCR) for 13 respiratory viruses, and quantitative histology for inflammation of small airways.

RSV fusion: time for a new model.

In this review we propose a partially hypothetical model of respiratory syncytial virus (RSV) binding and entry to the cell that includes the recently discovered RSV receptor nucleolin, in an attempt to stimulate further inquiry in this research area. RSV binding and entry is likely to be a two-step process, the first involving the attachment of the virus to the cell membrane, which may be enhanced by electrostatic interactions with cellular glycoproteins/heparin and the viral G protein, and the second involving fusion to the cell membrane mediated by the viral F protein and a specific cellular fusion receptor. With our recent discovery of nucleolin as a functional fusion receptor for RSV, comes the possibility of a number of new approaches to the development of novel strategies for RSV prophylaxis and therapy, as well as raising some new questions concerning the pathobiology of RSV infection and tropism.

Functional genetic variation in NFKBIA and susceptibility to childhood asthma, bronchiolitis, and bronchopulmonary dysplasia.

Respiratory diseases are the most frequent chronic illnesses in babies and children. Although a vigorous innate immune system is critical for maintaining lung health, a balanced response is essential to minimize damaging inflammation. We investigated the functional and clinical impact of human genetic variants in the promoter of NFKBIA, which encodes IκBα, the major negative regulator of NF-κB.

Host and Viral Factors in Respiratory Syncytial Virus Infection.

Respiratory syncytial virus (RSV) is a major worldwide pathogen for which there is still no effective vaccine or antiviral treatment available, and immunoprophylaxis with RSV-specific antibodies (e.g., palivizumab) is used in limited clinical settings.

Formation of a stable mimic of ambient particulate matter containing viable infectious respiratory syncytial virus and its dry-deposition directly onto cell cultures.

Epidemiological associations of worse respiratory outcomes from combined exposure to ambient particulate matter (PM) and respiratory viral infection suggest possible interactions between PM and viruses. To characterize outcomes of such exposures, we developed an in vitro mimic of the in vivo event of exposure to PM contaminated with respiratory syncytial virus (RSV). Concentration of infectious RSV stocks and a particle levitation apparatus were the foundations of the methodology developed to generate specific numbers of PM mimics (PM(Mimics)) of known composition for dry, direct deposition onto airway epithelial cell cultures.

Associations and interactions of genetic polymorphisms in innate immunity genes with early viral infections and susceptibility to asthma and asthma-related phenotypes.

Background: The innate immune system is essential for host survival because of its ability to recognize invading pathogens and mount defensive responses.

Objectives: We sought to identify genetic associations of innate immunity genes with atopy and asthma and interactions with early viral infections (first 12 months of life) in a high-risk birth cohort.

Methods: Three Canadian family-based studies and 1 Australian population-based case-control study (n = 5565) were used to investigate associations of 321 single nucleotide polymorphisms (SNPs) in 26 innate immunity genes with atopy, asthma, atopic asthma, and airway hyperresponsiveness.

The RSV fusion receptor: not what everyone expected it to be.

This article reviews current knowledge about respiratory syncytial virus (RSV) binding and entry into cells. The recent discovery of Nucleolin as a fusion receptor for RSV opens new avenues for developing interventions, while raising questions concerning RSV pathobiology and tropism. We also discuss characteristics of a good RSV drug target.

Identifying targets in the hunt for effective respiratory syncytial virus interventions.

Respiratory syncytial virus (RSV) is a major cause of human infections worldwide. There is currently no effective vaccine or antiviral therapy available for widespread clinical use; prophylaxis with anti-RSV antibodies is used in only a small percentage of potential recipients. New targets for effective RSV interventions are needed.

Is thrombotic microangiopathy a paraneoplastic phenomenon? Case report and review of the literature.

It is currently recognized that the pathogenesis of malignancy-associated thrombotic microangiopathy (TMA) is distinct from thrombotic thrombocytopenic purpura. This carries important implications in its classification and its management. Here, we report a case of occult malignancy presenting initially as acute kidney injury secondary to TMA and highlight the importance of considering an underlying malignancy in patients not responding to conventional therapy for TMA.

Identification of nucleolin as a cellular receptor for human respiratory syncytial virus.

Human respiratory syncytial virus (RSV) causes a large burden of disease worldwide. There is no effective vaccine or therapy, and the use of passive immunoprophylaxis with RSV-specific antibodies is limited to high-risk patients. The cellular receptor (or receptors) required for viral entry and replication has yet to be described; its identification will improve understanding of the pathogenesis of infection and provide a target for the development of novel antiviral interventions.

Intrinsic phenotypic differences of asthmatic epithelium and its inflammatory responses to respiratory syncytial virus and air pollution.

A substantial proportion of healthcare cost associated with asthma is attributable to exacerbations of the disease. Within the airway, the epithelium forms the mucosal immune barrier, the first structural cell defense against common environmental insults such as respiratory syncytial virus (RSV) and particulate matter. We sought to characterize the phenotype of differentiated asthmatic-derived airway epithelial cultures and their intrinsic inflammatory responses to environmental challenges.

The relationship between respiratory viral loads and diagnosis in children presenting to a pediatric hospital emergency department.

Background: respiratory viral infections account for a considerable proportion of pediatric emergency room visits. Illnesses range in severity from mild upper respiratory tract infections to serious lower respiratory tract infections (LRTI). The relationship between viral load and specific viruses to clinical diagnosis made by physicians in this setting is poorly understood.

Toll-like receptor 4-mediated activation of p38 mitogen-activated protein kinase is a determinant of respiratory virus entry and tropism.

Respiratory viruses exert a heavy toll of morbidity and mortality worldwide. Despite this burden there are few specific treatments available for respiratory virus infections. Since many viruses utilize host cell enzymatic machinery such as protein kinases for replication, we determined whether pharmacological inhibition of kinases could, in principle, be used as a broad antiviral strategy for common human respiratory virus infections.

Rosai-Dorfman disease involving the neurohypophysis.

Rosai-Dorfman disease is a rare, histiocytic proliferative disorder of unknown etiology commonly affecting lymph nodes. Extranodal lesions with or without nodal involvement also occur. We report the case of a 63 year-old woman with disseminated Rosai-Dorfman disease involving the neurohypophysis and associated with adenohypophysial PRL cell hyperplasia.