scholarly journals The Regulation of Flavivirus Infection by Hijacking Exosome-Mediated Cell–Cell Communication: New Insights on Virus–Host Interactions

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 765
Author(s):  
José Manuel Reyes-Ruiz ◽  
Juan Fidel Osuna-Ramos ◽  
Luis Adrián De Jesús-González ◽  
Selvin Noé Palacios-Rápalo ◽  
Carlos Daniel Cordero-Rivera ◽  
...  
Keyword(s):  
Viral Infections ◽  
Cell Communication ◽  
Cell Interaction ◽  
Host Cells ◽  
Human Pathogens ◽  
Cellular Functions ◽  
Cellular Targets ◽  
Host Interaction ◽  
Flavivirus Infection

The arthropod-borne flaviviruses are important human pathogens, and a deeper understanding of the virus–host cell interaction is required to identify cellular targets that can be used as therapeutic candidates. It is well reported that the flaviviruses hijack several cellular functions, such as exosome-mediated cell communication during infection, which is modulated by the delivery of the exosomal cargo of pro- or antiviral molecules to the receiving host cells. Therefore, to study the role of exosomes during flavivirus infections is essential, not only to understand its relevance in virus–host interaction, but also to identify molecular factors that may contribute to the development of new strategies to block these viral infections. This review explores the implications of exosomes in flavivirus dissemination and transmission from the vector to human host cells, as well as their involvement in the host immune response. The hypothesis about exosomes as a transplacental infection route of ZIKV and the paradox effect or the dual role of exosomes released during flavivirus infection are also discussed here. Although several studies have been performed in order to identify and characterize cellular and viral molecules released in exosomes, it is not clear how all of these components participate in viral pathogenesis. Further studies will determine the balance between protective and harmful exosomes secreted by flavivirus infected cells, the characteristics and components that distinguish them both, and how they could be a factor that determines the infection outcome.

scholarly journals Cathepsins: innate immune proteases that regulate viral entry into host cells

2018 ◽  
Vol 72 ◽  
pp. 253-263 ◽  
Author(s):  
Magdalena Bossowska-Nowicka ◽  
Felix N. Toka ◽  
Matylda Mielcarska ◽  
Lidia Szulc-Dąbrowska
Keyword(s):  
Viral Entry ◽  
Antigen Processing ◽  
Viral Infections ◽  
Innate Immune ◽  
Host Cells ◽  
Human Pathogens ◽  
Cellular Mechanisms ◽  
Cathepsin Proteases ◽  
Cell Adhesion And Migration

Cathepsins are group of endolysosomal proteases that regulate the mechanisms of innate and adaptive immunity, including cell adhesion and migration, antigen processing and presentation and resistance to several viral infections. Some cathepsins are required for Toll-like receptor (TLR)3, TLR7 and TLR9 cleavage and the formation of functional receptors that participate in sensing viral nucleic acids. Moreover, cathepsins directly stimulate or inhibit cytokine secretion involved in the regulation of antiviral innate immune response. Recent findings underline the important role of cathepsins in the entry of filoviruses, reoviruses, retroviruses and other types of viruses into the host cell. Many enveloped viruses require the presence of cathepsins for efficient fusion with membranes of infected cells, and the inhibition of their activity results in a significant reduction of virus replication. In addition, many viruses utilize conserved cellular mechanisms, such as endocytosis or low pH within the endosome, for efficient penetration into the cell interior, disassembly of viral capsid, and other stages of productive viral replication cycle. Therefore, a better understanding of the functional role of cathepsin proteases in the pathogenesis of viral infections should lead to the development of novel therapeutics for a variety of particularly dangerous human pathogens.

The Role of microRNAs in the Viral Infections

2019 ◽  
Vol 24 (39) ◽  
pp. 4659-4667 ◽  
Author(s):  
Mona Fani ◽  
Milad Zandi ◽  
Majid Rezayi ◽  
Nastaran Khodadad ◽  
Hadis Langari ◽  
...  
Keyword(s):  
Viral Infections ◽  
Rna Viruses ◽  
Regulation Of Gene Expression ◽  
Molecular Structures ◽  
Main Function ◽  
Cellular Functions ◽  
Viral Genes ◽  
Non Coding Rnas ◽  
Post Transcriptional Regulation

MicroRNAs (miRNAs) are non-coding RNAs with 19 to 24 nucleotides which are evolutionally conserved. MicroRNAs play a regulatory role in many cellular functions such as immune mechanisms, apoptosis, and tumorigenesis. The main function of miRNAs is the post-transcriptional regulation of gene expression via mRNA degradation or inhibition of translation. In fact, many of them act as an oncogene or tumor suppressor. These molecular structures participate in many physiological and pathological processes of the cell. The virus can also produce them for developing its pathogenic processes. It was initially thought that viruses without nuclear replication cycle such as Poxviridae and RNA viruses can not code miRNA, but recently, it has been proven that RNA viruses can also produce miRNA. The aim of this articles is to describe viral miRNAs biogenesis and their effects on cellular and viral genes.

scholarly journals Silver Nanoparticles as Potential Antiviral Agents

Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2034
Author(s):  
Zubair Ahmed Ratan ◽  
Fazla Rabbi Mashrur ◽  
Anisha Parsub Chhoan ◽  
Sadi Md. Shahriar ◽  
Mohammad Faisal Haidere ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Potential Role ◽  
Viral Infections ◽  
Antiviral Agents ◽  
Host Cells ◽  
Characterization Methods ◽  
New Horizons ◽  
Bacteria And Fungi ◽  
The Impact

Since the early 1990s, nanotechnology has led to new horizons in nanomedicine, which encompasses all spheres of science including chemistry, material science, biology, and biotechnology. Emerging viral infections are creating severe hazards to public health worldwide, recently, COVID-19 has caused mass human casualties with significant economic impacts. Interestingly, silver nanoparticles (AgNPs) exhibited the potential to destroy viruses, bacteria, and fungi using various methods. However, developing safe and effective antiviral drugs is challenging, as viruses use host cells for replication. Designing drugs that do not harm host cells while targeting viruses is complicated. In recent years, the impact of AgNPs on viruses has been evaluated. Here, we discuss the potential role of silver nanoparticles as antiviral agents. In this review, we focus on the properties of AgNPs such as their characterization methods, antiviral activity, mechanisms, applications, and toxicity.

scholarly journals Recent Updates on Research Models and Tools to Study Virus–Host Interactions at the Placenta

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 5 ◽  
Author(s):  
Jae Kyung Lee ◽  
Soo-Jin Oh ◽  
Hosun Park ◽  
Ok Sarah Shin
Keyword(s):  
Viral Infections ◽  
Protective Role ◽  
Biological Mechanisms ◽  
Cellular Targets ◽  
Host Interactions ◽  
Wide Range ◽  
Hofbauer Cells ◽  
Maternal Fetal Transmission ◽  
Immunological Barrier

The placenta is a unique mixed organ, composed of both maternal and fetal tissues, that is formed only during pregnancy and serves as the key physiological and immunological barrier preventing maternal–fetal transmission of pathogens. Several viruses can circumvent this physical barrier and enter the fetal compartment, resulting in miscarriage, preterm birth, and birth defects, including microcephaly. The mechanisms underlying viral strategies to evade the protective role of placenta are poorly understood. Here, we reviewed the role of trophoblasts and Hofbauer cells in the placenta and have highlighted characteristics of vertical and perinatal infections caused by a wide range of viruses. Moreover, we explored current progress and future opportunities in cellular targets, pathogenesis, and underlying biological mechanisms of congenital viral infections, as well as novel research models and tools to study the placenta.

Racemization Hypothesis of COVID-19. Tip of the Iceberg

2020 ◽  
Keyword(s):  
Phase Transitions ◽  
Host Cell ◽  
Viral Infections ◽  
Proteolytic Enzymes ◽  
Viral Proteins ◽  
Cell Interaction ◽  
Cell Physiology ◽  
Viral Glycoprotein ◽  
Host Interaction ◽  
The Impact

The impact of viral infections on the central nervous system is widely known. Virus-related neuropsychiatric and neurobehavioral syndromes are caused by the distortion of cognitive, affective, behavioral, and perceptual domains. Although it is a commonly known phenomenon, the mechanism behind it is not well-understood. The contagious and deadly features of coronavirus disease 2019 (COVID-19) have been associated with the virus-host cell interaction at the molecular level. However, there is no reliable biomarker characterizing the disease progression. Studies of the structure, function, and evolution of coronavirus transmembrane spike glycoproteins (S-, N-, and E-proteins) suggest an essential role of protein chirality in virus-cell membrane interaction. The virus-host interaction is the subject of multidisciplinary research from the biochirality and systems biology, to cell physiology and non-equilibrium thermodynamics of phase transitions in proteins. At the protein level, virus-host interaction is modulated by the amino acid sequence of viral proteins and cellular metabolism. Enzymatic and spontaneous post-translational modifications (PTMs) are two mutually influential mechanisms governing the dynamics of virus and host cell proteome. Among them, phosphorylation and racemization are the most inter-related and studied. The spontaneous phase transitions within viral glycoprotein impacts the cell-entry capability of the virus. The spontaneous racemization is a particular and highly specific metabolic event in virus-cell interaction that is the focus of our attention. Many viral proteins are characterized by a high proportion of the serine (Ser) residues, which are the common target of the host-cell glycosylation, phosphorylation, and racemization, and proteolytic enzymes. Particularly, coronavirus N proteins were found to be phosphorylated at multiple Ser residues, a portion of which are shown to be phosphorylation-prone by the Ser-associated kinases. Since Ser is known as one of the most racemization prone amino acids, we promote an idea of the specific impact of spontaneous racemization at Ser residues on virus-host interaction.

scholarly journals Interrelationships of Interferon and Immunity During Viral Infections

1970 ◽  
Vol 56 (1) ◽  
pp. 212-226 ◽  
Author(s):  
Lowell A. Glasgow
Keyword(s):  
Immune Responses ◽  
Vaccinia Virus ◽  
Host Resistance ◽  
Host Response ◽  
Viral Infections ◽  
Cell Interaction ◽  
Relative Importance ◽  
Host Interaction ◽  
Interferon Responses

Interferon is one determinant of host resistance. The immune responses, cellular or humoral, are other components. Cell-mediated responses appear to be involved in host resistance to certain viral infections, particularly the herpesvirus group and vaccinia virus. It is suggested that immune and interferon responses may complement one another and contribute to host resistance. The relative importance of each component depends upon the virus-host interaction. Finally, evidence has been presented which suggests that production of interferon as a result of antigen-sensitized cell interaction may further link these two components of the host response.

scholarly journals MiR-146a in Immunity and Disease

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Nicole Rusca ◽  
Silvia Monticelli
Keyword(s):  
Immune Responses ◽  
Recent Progress ◽  
Viral Infections ◽  
Cellular Functions ◽  
Adaptive Immune Responses ◽  
Adaptive Immune ◽  
Different Types ◽  
A Cell ◽  
And Function

MicroRNAs (miRNAs) are regulatory molecules able to influence all aspects of the biology of a cell. They have been associated with diseases such as cancer, viral infections, and autoimmune diseases, and in recent years, they also emerged as important regulators of immune responses. MiR-146a in particular is rapidly gaining importance as a modulator of differentiation and function of cells of the innate as well as adaptive immunity. Given its importance in regulating key cellular functions, it is not surprising that miR-146a expression was also found dysregulated in different types of tumors. In this paper, we summarize recent progress in understanding the role of miR-146a in innate and adaptive immune responses, as well as in disease.

scholarly journals Critical Negatively Charged Residues Are Important for the Activity of SARS-CoV-1 and SARS-CoV-2 Fusion Peptides

2021 ◽  
Author(s):  
Alex L. Lai ◽  
Jack H. Freed
Keyword(s):  
Critical Role ◽  
Binding Energies ◽  
Host Cells ◽  
Topological Model ◽  
Pseudotyped Virus ◽  
Fusion Peptides ◽  
Human Pathogens ◽  
Charged Residues ◽  
The Difference

AbstractCoronaviruses are a major infectious disease threat, and include the human pathogens of zoonotic origin SARS-CoV (“SARS-1”), SARS-CoV-2 (“SARS-2”) and MERS-CoV (“MERS”). Entry of coronaviruses into host cells is mediated by the viral spike (S) protein. Previously, we identified that the domain immediately downstream of the S2’ cleavage site is the bona fide FP (amino acids 798-835) for SARS-1 using ESR spectroscopy technology. We also found that the SARS-1 FP induces membrane ordering in a Ca2+ dependent fashion. In this study, we want to know which residues are involved in this Ca2+ binding, to build a topological model and to understand the role of the Ca2+. We performed a systematic mutation study on the negatively charged residues on the SARS-1 FP. While all six negatively charged residues contributes to the membrane ordering activity of the FP to some extent, D812 is the most important residue. We provided a topological model of how the FP binds Ca2+ ions: both FP1 and FP2 bind one Ca2+ ion, and there are two binding sites in FP1 and three in FP2. We also found that the corresponding residue D830 in the SARS-2 FP plays a similar critical role. ITC experiments show that the binding energies between the FP and Ca2+ as well as between the FP and membranes also decreases for all mutants. The binding of Ca2+, the folding of FP and the ordering activity correlated very well across the mutants, suggesting that the function of the Ca2+ is to help to folding of FP in membranes to enhance its activity. Using a novel pseudotyped virus particle (PP)-liposome methodology, we monitored the membrane ordering induced by the FPs in the whole S proteins in its trimer form in real time. We found that the SARS-1 and SARS-2 PPs also induce membrane ordering as the separate FPs do, and the mutations of the negatively charged residues also greatly reduce the membrane ordering activity. However, the difference in kinetic between the PP and FP indicates a possible role of FP trimerization. This finding could lead to therapeutic solutions that either target the FP-calcium interaction or block the Ca2+ channel to combat the ongoing COVID-19 pandemic.

Racemization Hypothesis of COVID-19. Tip of the Iceberg

2020 ◽  
Keyword(s):  
Phase Transitions ◽  
Host Cell ◽  
Viral Infections ◽  
Proteolytic Enzymes ◽  
Viral Proteins ◽  
Cell Interaction ◽  
Cell Physiology ◽  
Viral Glycoprotein ◽  
Host Interaction ◽  
The Impact

The impact of viral infections on the central nervous system is widely known. Virus-related neuropsychiatric and neurobehavioral syndromes are caused by the distortion of cognitive, affective, behavioral, and perceptual domains. Although it is a commonly known phenomenon, the mechanism behind it is not well-understood. The contagious and deadly features of coronavirus disease 2019 (COVID-19) have been associated with the virus-host cell interaction at the molecular level. However, there is no reliable biomarker characterizing the disease progression. Studies of the structure, function, and evolution of coronavirus transmembrane spike glycoproteins (S-, N-, and E-proteins) suggest an essential role of protein chirality in virus-cell membrane interaction. The virus-host interaction is the subject of multidisciplinary research from the biochirality and systems biology, to cell physiology and non-equilibrium thermodynamics of phase transitions in proteins. At the protein level, virus-host interaction is modulated by the amino acid sequence of viral proteins and cellular metabolism. Enzymatic and spontaneous post-translational modifications (PTMs) are two mutually influential mechanisms governing the dynamics of virus and host cell proteome. Among them, phosphorylation and racemization are the most inter-related and studied. The spontaneous phase transitions within viral glycoprotein impacts the cell-entry capability of the virus. The spontaneous racemization is a particular and highly specific metabolic event in virus-cell interaction that is the focus of our attention. Many viral proteins are characterized by a high proportion of the serine (Ser) residues, which are the common target of the host-cell glycosylation, phosphorylation, and racemization, and proteolytic enzymes. Particularly, coronavirus N proteins were found to be phosphorylated at multiple Ser residues, a portion of which are shown to be phosphorylation-prone by the Ser-associated kinases. Since Ser is known as one of the most racemization prone amino acids, we promote an idea of the specific impact of spontaneous racemization at Ser residues on virus-host interaction.

scholarly journals Host Calcium Channels and Pumps in Viral Infections

Cells ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 94 ◽  
Author(s):  
Xingjuan Chen ◽  
Ruiyuan Cao ◽  
Wu Zhong
Keyword(s):  
Calcium Channels ◽  
Calcium Release ◽  
Transient Receptor Potential ◽  
Viral Infections ◽  
Receptor Potential ◽  
Host Cells ◽  
Viral Gene ◽  
Host Interaction ◽  
Transduction Mechanisms ◽  
Transient Receptor

Ca2+ is essential for virus entry, viral gene replication, virion maturation, and release. The alteration of host cells Ca2+ homeostasis is one of the strategies that viruses use to modulate host cells signal transduction mechanisms in their favor. Host calcium-permeable channels and pumps (including voltage-gated calcium channels, store-operated channels, receptor-operated channels, transient receptor potential ion channels, and Ca2+-ATPase) mediate Ca2+ across the plasma membrane or subcellular organelles, modulating intracellular free Ca2+. Therefore, these Ca2+ channels or pumps present important aspects of viral pathogenesis and virus–host interaction. It has been reported that viruses hijack host calcium channels or pumps, disturbing the cellular homeostatic balance of Ca2+. Such a disturbance benefits virus lifecycles while inducing host cells’ morbidity. Evidence has emerged that pharmacologically targeting the calcium channel or calcium release from the endoplasmic reticulum (ER) can obstruct virus lifecycles. Impeding virus-induced abnormal intracellular Ca2+ homeostasis is becoming a useful strategy in the development of potent antiviral drugs. In this present review, the recent identified cellular calcium channels and pumps as targets for virus attack are emphasized.

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