scholarly journals Human parvovirus B19 interacts with globoside under acidic conditions as an essential step in endocytic trafficking

2021 ◽  
Vol 17 (4) ◽  
pp. e1009434
Author(s):  
Jan Bieri ◽  
Remo Leisi ◽  
Cornelia Bircher ◽  
Carlos Ros
Keyword(s):  
Parvovirus B19 ◽  
Endocytic Trafficking ◽  
Erythroid Cells ◽  
Binding Assays ◽  
Essential Step ◽  
Viral Particles ◽  
Internalization Process ◽  
Intracellular Compartments ◽  
Acidic Conditions

The glycosphingolipid (GSL) globoside (Gb4) is essential for parvovirus B19 (B19V) infection. Historically considered the cellular receptor of B19V, the role of Gb4 and its interaction with B19V are controversial. In this study, we applied artificial viral particles, genetically modified cells, and specific competitors to address the interplay between the virus and the GSL. Our findings demonstrate that Gb4 is not involved in the binding or internalization process of the virus into permissive erythroid cells, a function that corresponds to the VP1u cognate receptor. However, Gb4 is essential at a post-internalization step before the delivery of the single-stranded viral DNA into the nucleus. In susceptible erythroid Gb4 knockout cells, incoming viruses were arrested in the endosomal compartment, showing no cytoplasmic spreading of capsids as observed in Gb4-expressing cells. Hemagglutination and binding assays revealed that pH acts as a switch to modulate the affinity between the virus and the GSL. Capsids interact with Gb4 exclusively under acidic conditions and dissociate at neutral pH. Inducing a specific Gb4-mediated attachment to permissive erythroid cells by acidification of the extracellular environment led to a non-infectious uptake of the virus, indicating that low pH-mediated binding to the GSL initiates active membrane processes resulting in vesicle formation. In summary, this study provides mechanistic insight into the interaction of B19V with Gb4. The strict pH-dependent binding to the ubiquitously expressed GSL prevents the redirection of the virus to nonpermissive tissues while promoting the interaction in acidic intracellular compartments as an essential step in infectious endocytic trafficking.

scholarly journals Human parvovirus B19 interacts with globoside under acidic conditions as an essential step in endocytic trafficking

2021 ◽  
Author(s):  
Jan Bieri ◽  
Remo Leisi ◽  
Cornelia Bircher ◽  
Carlos Ros
Keyword(s):  
Parvovirus B19 ◽  
Endocytic Trafficking ◽  
Cellular Receptor ◽  
Erythroid Cells ◽  
Binding Assays ◽  
Essential Step ◽  
Internalization Process ◽  
Acidic Conditions ◽  
Infectious Entry

AbstractThe glycosphingolipid (GSL) globoside (Gb4) is essential for parvovirus B19 (B19V) infection. Historically considered the cellular receptor of B19V, the role of Gb4 and its interaction with B19V are controversial. In this study, we applied artificial viral particles, genetically modified cells, and specific competitors to address the interplay between the virus and the GSL. Our findings demonstrate that Gb4 is not involved in the binding or internalization process of the virus into permissive erythroid cells, a function that corresponds to the VP1u cognate receptor. However, Gb4 is essential at a post-internalization step before the delivery of the single-stranded viral DNA into the nucleus. In susceptible erythroid Gb4 knockout cells, incoming viruses were arrested in the endosomal compartment, showing no cytoplasmic spreading of capsids as observed in Gb4-expressing cells. Hemagglutination and binding assays revealed that pH acts as a switch to modulate the affinity between the virus and the GSL. Capsids interact with Gb4 exclusively under acidic conditions and dissociate at neutral pH. Inducing a specific Gb4-mediated attachment to permissive erythroid cells by acidification of the extracellular environment led to a non-infectious uptake of the virus, indicating that low pH-mediated binding to the GSL initiates active membrane processes resulting in vesicle formation. In summary, this study provides mechanistic insight into the interaction of B19V with Gb4. The strict pH-dependent binding to the ubiquitously expressed GSL prevents the redirection of the virus to nonpermissive tissues while promoting the interaction in acidic intracellular compartments as an essential step in infectious endocytic trafficking.Author summaryThe neutral glycosphingolipid globoside (Gb4) has been historically considered the cellular receptor of B19V, however, its wide expression profile does not correlate well with the restricted tropism of the virus. Here, we show that Gb4 is essential for the infection at a step following virus uptake and before the delivery of the viral ssDNA into the nucleus. B19V interacts with Gb4 exclusively under acidic conditions, prohibiting the interaction on the plasma membrane and promoting it inside the acidic endosomal compartments, which are engaged by the virus and the GSL after internalization. In the absence of Gb4, incoming viruses are retained in the endocytic compartment and the infection is aborted. This study reveals the mechanism of the interaction between the virus and the glycosphingolipid and redefines the role of Gb4 as an essential intracellular partner required for infectious entry.

scholarly journals Including the animal standpoint in critical public relations research

2021 ◽  
Vol 10 (2) ◽  
pp. 139-161
Author(s):  
Núria Almiron ◽  
Laura Fernández
Keyword(s):  
Political Economy ◽  
Public Relations ◽  
Animal Studies ◽  
Critical Animal Studies ◽  
Essential Step ◽  
Challenges And Opportunities ◽  
Discourse Studies ◽  
Theoretical Paper ◽  
Short Explanation

In this paper we argue that adopting critical animal studies perspectives in critical public relations can not only be very fruitful, but that it is also a necessity if the aims of the latter are to be achieved. To this end, this text introduces the challenges and opportunities that the field of critical animal studies brings to critical public relations studies. First, a short explanation of what critical animal studies is and why it can contribute to critical public relations studies is provided. Then the main fields of research where this contribution can be most relevant are discussed, including ethics, discourse studies and political economy. The final aim of this theoretical paper is to expand research within the field of critical public relations by including a critical animal studies approach. Eventually, the authors suggest that embracing the animal standpoint in critical public relations is an essential step to furthering the study of power, hegemony, ideology, propaganda or social change and to accomplishing the emancipatory role of research.

Identifying the etiologic role of Parvovirus B19 in non-immune hydrops fetalis by histopathology, immunohistochemistry and nucleic acid testing: a retrospective study

Open Medicine ◽  
2007 ◽  
Vol 2 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Koray Ergunay ◽  
Gulcin Altinok ◽  
Bora Gurel ◽  
Ahmet Pinar ◽  
Arzu Sungur ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Real Time ◽  
San Francisco ◽  
Real Time Pcr ◽  
Nested Pcr ◽  
Parvovirus B19 ◽  
Etiologic Agent ◽  
Hydrops Fetalis ◽  
Nucleic Acid Detection

AbstractIntrauterine Parvovirus B19 infections may cause fetal anemia, non-immune hydrops fetalis or abortion. This study focuses on the pathogenic role of Parvovirus B19 in non-immune hydrops fetalis at Hacettepe University, a major reference hospital in Turkey. Twenty-two cases of non-immune hydrops fetalis were retrospectively selected out of a total of 431 hydrops fetalis specimens from the Department of Pathology archieves. Paraffine embedded tissue sections from placental and liver tissues from each case were evaluated by histopathology, immunohistochemistry, nested PCR and commercial quantitative Real-time PCR. Viral DNA was detected in placental tissues by Real-time PCR in 2 cases (2/22, 9.1%) where histopathology also revealed changes suggestive of Parvovirus B19 infection. No significant histopathologic changes were observed for the remaining sections. Nested PCR that targets the VP1 region of the viral genome and immunohistochemistry for viral capsid antigens were negative for all cases. As a result, Parvovirus B19 is identified as the etiologic agent for the development of non-immune hydrops fetalis for 9.1% of the cases in Hacettepe University, Turkey. Real-time PCR is observed to be an effective diagnostic tool for nucleic acid detection from paraffine embedded tissues. Part of this study was presented as a poster at XIIIth International Congress of Virology, San Francisco, USA (Abstract V-572).

scholarly journals Antiviral Role of Phenolic Compounds against Dengue Virus: A Review

Biomolecules ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Vanessa Loaiza-Cano ◽  
Laura Milena Monsalve-Escudero ◽  
Carlos da Silva Maia Bezerra Filho ◽  
Marlen Martinez-Gutierrez ◽  
Damião Pergentino de Sousa
Keyword(s):  
Phenolic Compounds ◽  
Dengue Virus ◽  
Biological Activities ◽  
Antiviral Effect ◽  
Health Concern ◽  
Host Proteins ◽  
Viral Particles ◽  
Antiviral Role ◽  
Productive Replication

Phenolic compounds have been related to multiple biological activities, and the antiviral effect of these compounds has been demonstrated in several viral models of public health concern. In this review, we show the antiviral role of phenolic compounds against dengue virus (DENV), the most widespread arbovirus globally that, after its re-emergence, has caused multiple epidemic outbreaks, especially in the last two years. Twenty phenolic compounds with anti-DENV activity are discussed, including the multiple mechanisms of action, such as those directed against viral particles or viral proteins, host proteins or pathways related to the productive replication viral cycle and the spread of the infection.

scholarly journals Role of the V1G1 subunit of V-ATPase in breast cancer cell migration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria De Luca ◽  
Roberta Romano ◽  
Cecilia Bucci
Keyword(s):  
Breast Cancer ◽  
Cell Migration ◽  
Cell Motility ◽  
Cancer Progression ◽  
Tumor Formation ◽  
Downstream Signaling ◽  
Late Endosomes ◽  
Intracellular Compartments

AbstractV-ATPase is a large multi-subunit complex that regulates acidity of intracellular compartments and of extracellular environment. V-ATPase consists of several subunits that drive specific regulatory mechanisms. The V1G1 subunit, a component of the peripheral stalk of the pump, controls localization and activation of the pump on late endosomes and lysosomes by interacting with RILP and RAB7. Deregulation of some subunits of the pump has been related to tumor invasion and metastasis formation in breast cancer. We observed a decrease of V1G1 and RAB7 in highly invasive breast cancer cells, suggesting a key role of these proteins in controlling cancer progression. Moreover, in MDA-MB-231 cells, modulation of V1G1 affected cell migration and matrix metalloproteinase activation in vitro, processes important for tumor formation and dissemination. In these cells, characterized by high expression of EGFR, we demonstrated that V1G1 modulates EGFR stability and the EGFR downstream signaling pathways that control several factors required for cell motility, among which RAC1 and cofilin. In addition, we showed a key role of V1G1 in the biogenesis of endosomes and lysosomes. Altogether, our data describe a new molecular mechanism, controlled by V1G1, required for cell motility and that promotes breast cancer tumorigenesis.

scholarly journals Human Mucosal Mast Cells Capture HIV-1 and Mediate Viraltrans-Infection of CD4+T Cells

2015 ◽  
Vol 90 (6) ◽  
pp. 2928-2937 ◽  
Author(s):  
Ai-Ping Jiang ◽  
Jin-Feng Jiang ◽  
Ji-Fu Wei ◽  
Ming-Gao Guo ◽  
Yan Qin ◽  
...  
Keyword(s):  
T Cells ◽  
Mast Cells ◽  
Cell Surface ◽  
Bacterial Infections ◽  
Mucosal Mast Cells ◽  
Mucosal Tissues ◽  
Viral Particles ◽  
Molecular Patterns ◽  
Hiv 1

ABSTRACTThe gastrointestinal mucosa is the primary site where human immunodeficiency virus type 1 (HIV-1) invades, amplifies, and becomes persistently established, and cell-to-cell transmission of HIV-1 plays a pivotal role in mucosal viral dissemination. Mast cells are widely distributed in the gastrointestinal tract and are early targets for invasive pathogens, and they have been shown to have increased density in the genital mucosa in HIV-infected women. Intestinal mast cells express numerous pathogen-associated molecular patterns (PAMPs) and have been shown to combat various viral, parasitic, and bacterial infections. However, the role of mast cells in HIV-1 infection is poorly defined. In this study, we investigated their potential contributions to HIV-1 transmission. Mast cells isolated from gut mucosal tissues were found to express a variety of HIV-1 attachment factors (HAFs), such as DC-SIGN, heparan sulfate proteoglycan (HSPG), and α4β7 integrin, which mediate capture of HIV-1 on the cell surface. Intriguingly, following coculture with CD4+T cells, mast cell surface-bound viruses were efficiently transferred to target T cells. Prior blocking with anti-HAF antibody or mannan before coculture impaired viraltrans-infection. Cell-cell conjunctions formed between mast cells and T cells, to which viral particles were recruited, and these were required for efficient cell-to-cell HIV-1 transmission. Our results reveal a potential function of gut mucosal mast cells in HIV-1 dissemination in tissues. Strategies aimed at preventing viral capture and transfer mediated by mast cells could be beneficial in combating primary HIV-1 infection.IMPORTANCEIn this study, we demonstrate the role of human mast cells isolated from mucosal tissues in mediating HIV-1trans-infection of CD4+T cells. This finding facilitates our understanding of HIV-1 mucosal infection and will benefit the development of strategies to combat primary HIV-1 dissemination.

Ypsilon Schachtel, aDrosophilaY-box protein, acts antagonistically to Orb in theoskarmRNA localization and translation pathway

Development ◽  
2002 ◽  
Vol 129 (1) ◽  
pp. 197-209 ◽  
Author(s):  
Jennifer H. Mansfield ◽  
James E. Wilhelm ◽  
Tulle Hazelrigg
Keyword(s):  
Subcellular Localization ◽  
Essential Role ◽  
Genetic Interaction ◽  
Mrna Localization ◽  
Rna Localization ◽  
Essential Step ◽  
Positive Regulator ◽  
Body Patterning ◽  
Translational Regulators

Subcellular localization of mRNAs within the Drosophila oocyte is an essential step in body patterning. Yps, a Drosophila Y-box protein, is a component of an ovarian ribonucleoprotein complex that also contains Exu, a protein that plays an essential role in mRNA localization. Y-box proteins are known translational regulators, suggesting that this complex might regulate translation as well as mRNA localization. Here we examine the role of the yps gene in these events. We show that yps interacts genetically with orb, a positive regulator of oskar mRNA localization and translation. The nature of the genetic interaction indicates that yps acts antagonistically to orb. We demonstrate that Orb protein is physically associated with both the Yps and Exu proteins, and that this interaction is mediated by RNA. We propose a model wherein Yps and Orb bind competitively to oskar mRNA with opposite effects on translation and RNA localization.

scholarly journals The AP2 clathrin adaptor protein complex regulates the abundance of GLR-1 glutamate receptors in the ventral nerve cord of Caenorhabditis elegans

2015 ◽  
Vol 26 (10) ◽  
pp. 1887-1900 ◽  
Author(s):  
Steven D. Garafalo ◽  
Eric S. Luth ◽  
Benjamin J. Moss ◽  
Michael I. Monteiro ◽  
Emily Malkin ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Secretory Pathway ◽  
Adaptor Protein ◽  
Intracellular Compartments ◽  
Clathrin Adaptor ◽  
Strength And Plasticity

Regulation of glutamate receptor (GluR) abundance at synapses by clathrin-mediated endocytosis can control synaptic strength and plasticity. We take advantage of viable, null mutations in subunits of the clathrin adaptor protein 2 (AP2) complex in Caenorhabditis elegans to characterize the in vivo role of AP2 in GluR trafficking. In contrast to our predictions for an endocytic adaptor, we found that levels of the GluR GLR-1 are decreased at synapses in the ventral nerve cord (VNC) of animals with mutations in the AP2 subunits APM-2/μ2, APA-2/α, or APS-2/σ2. Rescue experiments indicate that APM-2/μ2 functions in glr-1–expressing interneurons and the mature nervous system to promote GLR-1 levels in the VNC. Genetic analyses suggest that APM-2/μ2 acts upstream of GLR-1 endocytosis in the VNC. Consistent with this, GLR-1 accumulates in cell bodies of apm-2 mutants. However, GLR-1 does not appear to accumulate at the plasma membrane of the cell body as expected, but instead accumulates in intracellular compartments including Syntaxin-13– and RAB-14–labeled endosomes. This study reveals a novel role for the AP2 clathrin adaptor in promoting the abundance of GluRs at synapses in vivo, and implicates AP2 in the regulation of GluR trafficking at an early step in the secretory pathway.

scholarly journals Recent insights into nitrite signaling processes in blood

2017 ◽  
Vol 398 (3) ◽  
pp. 319-329 ◽  
Author(s):  
Christine C. Helms ◽  
Xiaohua Liu ◽  
Daniel B. Kim-Shapiro
Keyword(s):  
Nitric Oxide ◽  
Human Physiology ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Nitrite Reduction ◽  
No Production ◽  
The Past ◽  
Acidic Conditions ◽  
Hypoxic Vasodilation

Abstract Nitrite was once thought to be inert in human physiology. However, research over the past few decades has established a link between nitrite and the production of nitric oxide (NO) that is potentiated under hypoxic and acidic conditions. Under this new role nitrite acts as a storage pool for bioavailable NO. The NO so produced is likely to play important roles in decreasing platelet activation, contributing to hypoxic vasodilation and minimizing blood-cell adhesion to endothelial cells. Researchers have proposed multiple mechanisms for nitrite reduction in the blood. However, NO production in blood must somehow overcome rapid scavenging by hemoglobin in order to be effective. Here we review the role of red blood cell hemoglobin in the reduction of nitrite and present recent research into mechanisms that may allow nitric oxide and other reactive nitrogen signaling species to escape the red blood cell.

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