scholarly journals Norovirus Attachment and Entry

Viruses ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 495 ◽  
Author(s):  
Vincent R. Graziano ◽  
Jin Wei ◽  
Craig B. Wilen
Keyword(s):  
Viral Entry ◽  
Molecular Mechanisms ◽  
Viral Gastroenteritis ◽  
Blood Group Antigens ◽  
Cell Tropism ◽  
Murine Norovirus ◽  
Human Norovirus ◽  
Future Directions ◽  
Minor Capsid Protein

Human norovirus is a major human pathogen causing the majority of cases of viral gastroenteritis globally. Viral entry is the first step of the viral life cycle and is a significant determinant of cell tropism, host range, immune interactions, and pathogenesis. Bile salts and histo-blood group antigens are key mediators of norovirus entry; however, the molecular mechanisms by which these molecules promote infection and the identity of a potential human norovirus receptor remain unknown. Recently, there have been several important advances in norovirus entry biology including the identification of CD300lf as the receptor for murine norovirus and of the role of the minor capsid protein VP2 in viral genome release. Here, we will review the current understanding about norovirus attachment and entry and highlight important future directions.

scholarly journals NMR Experiments Shed New Light on Glycan Recognition by Human and Murine Norovirus Capsid Proteins

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 416
Author(s):  
Robert Creutznacher ◽  
Thorben Maass ◽  
Patrick Ogrissek ◽  
Georg Wallmann ◽  
Clara Feldmann ◽  
...  
Keyword(s):  
Blood Group ◽  
Protein Interactions ◽  
Capsid Proteins ◽  
Blood Group Antigens ◽  
Biological Processes ◽  
Murine Norovirus ◽  
Human Norovirus ◽  
Head Groups ◽  
Significant Difference

Glycan–protein interactions are highly specific yet transient, rendering glycans ideal recognition signals in a variety of biological processes. In human norovirus (HuNoV) infection, histo-blood group antigens (HBGAs) play an essential but poorly understood role. For murine norovirus infection (MNV), sialylated glycolipids or glycoproteins appear to be important. It has also been suggested that HuNoV capsid proteins bind to sialylated ganglioside head groups. Here, we study the binding of HBGAs and sialoglycans to HuNoV and MNV capsid proteins using NMR experiments. Surprisingly, the experiments show that none of the norovirus P-domains bind to sialoglycans. Notably, MNV P-domains do not bind to any of the glycans studied, and MNV-1 infection of cells deficient in surface sialoglycans shows no significant difference compared to cells expressing respective glycans. These findings redefine glycan recognition by noroviruses, challenging present models of infection.

scholarly journals Enteric Viruses and Inflammatory Bowel Disease

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 104
Author(s):  
Georges Tarris ◽  
Alexis de Rougemont ◽  
Maëva Charkaoui ◽  
Christophe Michiels ◽  
Laurent Martin ◽  
...  
Keyword(s):  
Association Studies ◽  
Enteric Viruses ◽  
Enteric Virus ◽  
Viral Gastroenteritis ◽  
Blood Group Antigens ◽  
Genome Wide Association Studies ◽  
Virus Infections ◽  
T Helper ◽  
Inflammatory Bowel

Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), is a multifactorial disease in which dietary, genetic, immunological, and microbial factors are at play. The role of enteric viruses in IBD remains only partially explored. To date, epidemiological studies have not fully described the role of enteric viruses in inflammatory flare-ups, especially that of human noroviruses and rotaviruses, which are the main causative agents of viral gastroenteritis. Genome-wide association studies have demonstrated the association between IBD, polymorphisms of the FUT2 and FUT3 genes (which drive the synthesis of histo-blood group antigens), and ligands for norovirus and rotavirus in the intestine. The role of autophagy in defensin-deficient Paneth cells and the perturbations of cytokine secretion in T-helper 1 and T-helper 17 inflammatory pathways following enteric virus infections have been demonstrated as well. Enteric virus interactions with commensal bacteria could play a significant role in the modulation of enteric virus infections in IBD. Based on the currently incomplete knowledge of the complex phenomena underlying IBD pathogenesis, future studies using multi-sampling and data integration combined with new techniques such as human intestinal enteroids could help to decipher the role of enteric viruses in IBD.

scholarly journals Antibody Is Critical for the Clearance of Murine Norovirus Infection

2008 ◽  
Vol 82 (13) ◽  
pp. 6610-6617 ◽  
Author(s):  
Karen A. Chachu ◽  
David W. Strong ◽  
Anna D. LoBue ◽  
Christiane E. Wobus ◽  
Ralph S. Baric ◽  
...  
Keyword(s):  
Immune Response ◽  
B Cells ◽  
Murine Norovirus ◽  
Wild Type ◽  
Human Norovirus ◽  
Mucosal Infection ◽  
Antibody Levels ◽  
Deficient Mice ◽  
Immune Antibody

ABSTRACT Human noroviruses cause more than 90% of epidemic nonbacterial gastroenteritis. However, the role of B cells and antibody in the immune response to noroviruses is unclear. Previous studies have demonstrated that human norovirus specific antibody levels increase upon infection, but they may not be protective against infection. In this report, we used murine norovirus (MNV), an enteric norovirus, as a model to determine the importance of norovirus specific B cells and immune antibody in clearance of norovirus infection. We show here that mice genetically deficient in B cells failed to clear primary MNV infection as effectively as wild-type mice. In addition, adoptively transferred immune splenocytes derived from B-cell-deficient mice or antibody production-deficient mice were unable to efficiently clear persistent MNV infection in RAG1−/− mice. Further, adoptive transfer of either polyclonal anti-MNV serum or neutralizing anti-MNV monoclonal antibodies was sufficient to reduce the level of MNV infection both systemically and in the intestine. Together, these data demonstrate that antibody plays an important role in the clearance of MNV and that immunoglobulin G anti-norovirus antibody can play an important role in clearing mucosal infection.

Future Directions for Pharmacogenetics

1993 ◽  
Vol 6 (1) ◽  
pp. 44-46
Author(s):  
Michael W. Jann ◽  
Y.W. Francis Lam
Keyword(s):  
Molecular Mechanisms ◽  
Regulatory Control ◽  
Ethnic Variation ◽  
Metabolizing Enzymes ◽  
Future Directions ◽  
Clinical Investigations ◽  
Length Polymorphisms ◽  
Polymerase Chain

The discipline of pharmacogenetics will continue to expand as scientific and clinical investigations increase our understanding of genetic variabilities in drug metabolism and response. These research efforts will include determination of molecular mechanisms for the different polymorphisms and evaluation of their clinical significance. The availability of molecular methodologies such as restriction fragment length polymorphisms analysis, polymerase chain reaction, and expression of cDNAs in cell cultures will further the investigative work in detection of normal and mutant alleles, identification of new substrates for different polymorphic metabolizing enzymes, and evaluation of mechanisms of individual susceptibility to biological disorders. Other areas such as the role of pharmacogenetics in drug development and regulatory control, in evaluation of potential drug-drug interactions, ethnic variation in polymorphic metabolism, and response, also need to be evaluated.

Acquired cholesteatoma: summary of the cascade of molecular events

2013 ◽  
Vol 127 (6) ◽  
pp. 542-549 ◽  
Author(s):  
L Louw
Keyword(s):  
Molecular Mechanisms ◽  
Bone Erosion ◽  
Chronic Otitis Media ◽  
Future Directions ◽  
Molecular Events ◽  
Matrix Interactions ◽  
Proliferation And Apoptosis ◽  
Acquired Cholesteatoma ◽  
Role Players

AbstractBackground:Cholesteatoma is considered a benign, gradually expanding and destructive epithelial lesion of the temporal bone. The pathogenesis of different classifications of cholesteatoma is marked by similar underlying cellular and molecular processes. Stepwise explanations of the histopathogenesis have been described previously. The current paper focuses on expounding the molecular events of cholesteatoma.Method and results:Cholesteatoma pathogenesis encompasses a complex network of signalling pathways during: epidermal hyperplasia, perimatrix–matrix interactions and mucosal disease. This paper presents a review of the molecular events driven by inflammatory mediators and enzymes during: cholesteatoma growth (cell proliferation and apoptosis); maintenance and deterioration (angiogenesis and hypoxia, oxidative stress and toxicity); and complications (bone erosion and hearing loss). The cascade of molecular events applicable to atelectasis and cholesteatoma that coexist with chronic otitis media and bone erosion as sequelae is summarised.Conclusion:The role of lipids in this disease is relatively unexplored, but there is evidence in support of fatty acid role-players that needs confirmation. Future directions in lipid research to delineate molecular mechanisms are proposed.

scholarly journals Onset of Human Cytomegalovirus Replication in Fibroblasts Requires the Presence of an Intact Vimentin Cytoskeleton

2009 ◽  
Vol 83 (14) ◽  
pp. 7015-7028 ◽  
Author(s):  
Matthew S. Miller ◽  
Laura Hertel
Keyword(s):  
Intermediate Filaments ◽  
Human Cytomegalovirus ◽  
Viral Entry ◽  
Initial Phase ◽  
Axonal Neuropathy ◽  
Cell Tropism ◽  
Giant Axonal Neuropathy ◽  
Cmv Infection ◽  
Viral Particles

ABSTRACT Like all viruses, herpesviruses extensively interact with the host cytoskeleton during entry. While microtubules and microfilaments appear to facilitate viral capsid transport toward the nucleus, evidence for a role of intermediate filaments in herpesvirus entry is lacking. Here, we examined the function of vimentin intermediate filaments in fibroblasts during the initial phase of infection of two genotypically distinct strains of human cytomegalovirus (CMV), one with narrow (AD169) and one with broad (TB40/E) cell tropism. Chemical disruption of the vimentin network with acrylamide, intermediate filament bundling in cells from a patient with giant axonal neuropathy, and absence of vimentin in fibroblasts from vimentin−/− mice severely reduced entry of either strain. In vimentin null cells, viral particles remained in the cytoplasm longer than in vimentin+/+ cells. TB40/E infection was consistently slower than that of AD169 and was more negatively affected by the disruption or absence of vimentin. These findings demonstrate that an intact vimentin network is required for CMV infection onset, that intermediate filaments may function during viral entry to facilitate capsid trafficking and/or docking to the nuclear envelope, and that maintenance of a broader cell tropism is associated with a higher degree of dependence on the vimentin cytoskeleton.

scholarly journals A Single-Amino-Acid Substitution in the P2 Domain of VP1 of Murine Norovirus Is Sufficient for Escape from Antibody Neutralization

2007 ◽  
Vol 81 (22) ◽  
pp. 12316-12322 ◽  
Author(s):  
Vance P. Lochridge ◽  
Michele E. Hardy
Keyword(s):  
Amino Acid ◽  
Host Cells ◽  
Single Amino Acid ◽  
Carbohydrate Binding ◽  
Viral Gastroenteritis ◽  
Murine Norovirus ◽  
Norwalk Virus ◽  
Human Norovirus ◽  
Disulfide Linkage ◽  
Capsid Protein Vp1

ABSTRACT Noroviruses cause epidemic outbreaks of acute viral gastroenteritis worldwide, and the number of reported outbreaks is increasing. Human norovirus strains do not grow in cell culture. However, murine norovirus (MNV) replicates in the RAW 264.7 macrophage cell line and thus provides a tractable model to investigate norovirus interactions with host cells. Epitopes recognized by monoclonal antibodies (MAbs) against the human norovirus strains Norwalk virus and Snow Mountain virus (SMV) identified regions in the P domain of major capsid protein VP1 important for interactions with putative cellular receptors. To determine if there was a relationship between domains of MNV VP1 and VP1 of human norovirus strains involved in cell binding, epitope mapping by phage display was performed with an MNV-1-neutralizing MAb, A6.2.1. A consensus peptide, GWWEDHGQL, was derived from 20 third-round phage clones. A synthetic peptide containing this sequence and constrained through a disulfide linkage reacted strongly with the A6.2.1 MAb, whereas the linear sequence did not. Four residues in the A6.2.1-selected peptide, G327, G333, Q334, and L335, aligned with amino acid residues in the P2 domain of MNV-1 VP1. This sequence is immediately adjacent to the epitope recognized by anti-SMV MAb 61.21. Neutralization escape mutants selected with MAb A6.2.1 contained a leucine-to-phenylalanine substitution at position 386 in the P2 domain. The predicted location of these residues on VP1 suggests that the phage peptide and the mutation in the neutralization-resistant viruses may be in close proximity to each other and to residues reported to be important for carbohydrate binding to VP1 of human norovirus strains.

scholarly journals New Insights Into the Role of Aberrant Hippocampal Neurogenesis in Epilepsy

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Chen ◽  
Fuchao Chen ◽  
Yue Wu ◽  
Benhong Zhou
Keyword(s):  
Molecular Mechanisms ◽  
Wide Spectrum ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Future Directions ◽  
The Past ◽  
The Central Nervous System ◽  
Spontaneous Recurrent Seizures ◽  
Patients With Epilepsy

Data accumulated over the past four decades have confirmed that adult hippocampal neurogenesis (HN) plays a key role in the wide spectrum of hippocampal pathology. Epilepsy is a disorder of the central nervous system characterized by spontaneous recurrent seizures. Although neurogenesis in persistent germinative zones is altered in the adult rodent models of epilepsy, the effects of seizure-induced neurogenesis in the epileptic brain, in terms of either a pathological or reparative role, are only beginning to be explored. In this review, we described the most recent advances in neurogenesis in epilepsy and outlooked future directions for neural stem cells (NSCs) and epilepsy-in-a-dish models. We proposed that it may help in refining the underlying molecular mechanisms of epilepsy and improving the therapies and precision medicine for patients with epilepsy.

scholarly journals Specific Interactions between Human Norovirus and Environmental Matrices: Effects on the Virus Ecology

Viruses ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 224 ◽  
Author(s):  
Mohan Amarasiri ◽  
Daisuke Sano
Keyword(s):  
Extracellular Polymeric Substances ◽  
Current Knowledge ◽  
Enteric Bacteria ◽  
Blood Group Antigens ◽  
Dependent Manner ◽  
Specific Interactions ◽  
Environmental Matrices ◽  
Human Norovirus ◽  
Future Directions ◽  
Specific Receptors

Human norovirus is the major cause of non-bacterial epidemic gastroenteritis. Human norovirus binds to environmental solids via specific and non-specific interactions, and several specific receptors for human norovirus have been reported. Among them, histo-blood group antigens (HBGA) are the most studied specific receptor. Studies have identified the presence of HBGA-like substances in the extracellular polymeric substances (EPS) and lipopolysaccharides (LPS) of human enteric bacteria present in aquatic environments, gastrointestinal cells, gills, and palps of shellfish, and cell walls, leaves, and veins of lettuce. These HBGA-like substances also interact with human norovirus in a genotype-dependent manner. Specific interactions between human norovirus and environmental matrices can affect norovirus removal, infectivity, inactivation, persistence, and circulation. This review summarizes the current knowledge and future directions related to the specific interactions between human norovirus and HBGA-like substances in environmental matrices and their possible effects on the fate and circulation of human norovirus.

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