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1.
J Med Virol ; 93(11): 6116-6123, 2021 11.
Article in English | MEDLINE | ID: covidwho-1349155

ABSTRACT

Virus invasion activates the host's innate immune response, inducing the production of numerous cytokines and interferons to eliminate pathogens. Except for viral DNA/RNA, viral proteins are also targets of pattern recognition receptors. Membrane-bound receptors such as Toll-like receptor (TLR)1, TLR2, TLR4, TLR6, and TLR10 relate to the recognition of viral proteins. Distinct TLRs perform both protective and detrimental roles for a specific virus. Here, we review viral proteins serving as pathogen-associated molecular patterns and their corresponding TLRs. These viruses are all enveloped, including respiratory syncytial virus, hepatitis C virus, measles virus, herpesvirus human immunodeficiency virus, and coronavirus, and can encode proteins to activate innate immunity in a TLR-dependent way. The TLR-viral protein relationship plays an important role in innate immunity activation. A detailed understanding of their pathways contributes to a novel direction for vaccine development.


Subject(s)
Immunity, Innate , Pathogen-Associated Molecular Pattern Molecules/metabolism , Toll-Like Receptors/immunology , Toll-Like Receptors/metabolism , Viral Proteins/metabolism , Virus Diseases/immunology , Viruses/immunology , Animals , HIV/immunology , HIV/metabolism , HIV/pathogenicity , Hepacivirus/immunology , Hepacivirus/metabolism , Hepacivirus/pathogenicity , Herpesviridae/immunology , Herpesviridae/metabolism , Herpesviridae/pathogenicity , Humans , Measles virus/immunology , Measles virus/metabolism , Measles virus/pathogenicity , Pathogen-Associated Molecular Pattern Molecules/chemistry , Respiratory Syncytial Viruses/immunology , Respiratory Syncytial Viruses/metabolism , Respiratory Syncytial Viruses/pathogenicity , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Viral Proteins/chemistry , Virus Diseases/virology , Viruses/metabolism , Viruses/pathogenicity
2.
Antioxid Redox Signal ; 35(16): 1376-1392, 2021 12.
Article in English | MEDLINE | ID: covidwho-1342795

ABSTRACT

Significance: It is estimated that close to 50 million cases of sepsis result in over 11 million annual fatalities worldwide. The pathognomonic feature of sepsis is a dysregulated inflammatory response arising from viral, bacterial, or fungal infections. Immune recognition of pathogen-associated molecular patterns is a hallmark of the host immune defense to combat microbes and to prevent the progression to sepsis. Mitochondrial antiviral signaling protein (MAVS) is a ubiquitous adaptor protein located at the outer mitochondrial membrane, which is activated by the cytosolic pattern recognition receptors, retinoic acid-inducible gene I (RIG-I) and melanoma differentiation associated gene 5 (MDA5), following binding of viral RNA agonists. Recent Advances: Substantial progress has been made in deciphering the activation of the MAVS pathway with its interacting proteins, downstream signaling events (interferon [IFN] regulatory factors, nuclear factor kappa B), and context-dependent type I/III IFN response. Critical Issues: In the evolutionary race between pathogens and the host, viruses have developed immune evasion strategies for cleavage, degradation, or blockade of proteins in the MAVS pathway. For example, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) M protein and ORF9b protein antagonize MAVS signaling and a protective type I IFN response. Future Directions: The role of MAVS as a sensor for nonviral pathogens, host cell injury, and metabolic perturbations awaits better characterization in the future. New technical advances in multidimensional single-cell analysis and single-molecule methods will accelerate the rate of new discoveries. The ultimate goal is to manipulate MAVS activities in the form of immune-modulatory therapies to combat infections and sepsis. Antioxid. Redox Signal. 35, 1376-1392.


Subject(s)
Adaptor Proteins, Signal Transducing/immunology , Sepsis/immunology , Signal Transduction/immunology , Virus Diseases/immunology , Animals , Host-Pathogen Interactions/immunology , Humans , Immune Evasion/immunology , Sepsis/virology
3.
Sci Immunol ; 7(73): eabm7996, 2022 07 15.
Article in English | MEDLINE | ID: covidwho-1949936

ABSTRACT

The acute effects of various respiratory viral infections have been well studied, with extensive characterization of the clinical presentation as well as viral pathogenesis and host responses. However, over the course of the recent COVID-19 pandemic, the incidence and prevalence of chronic sequelae after acute viral infections have become increasingly appreciated as a serious health concern. Post-acute sequelae of COVID-19, alternatively described as "long COVID-19," are characterized by symptoms that persist for longer than 28 days after recovery from acute illness. Although there exists substantial heterogeneity in the nature of the observed sequelae, this phenomenon has also been observed in the context of other respiratory viral infections including influenza virus, respiratory syncytial virus, rhinovirus, severe acute respiratory syndrome coronavirus, and Middle Eastern respiratory syndrome coronavirus. In this Review, we discuss the various sequelae observed following important human respiratory viral pathogens and our current understanding of the immunological mechanisms underlying the failure of restoration of homeostasis in the lung.


Subject(s)
COVID-19 , Respiratory Tract Infections , Virus Diseases , COVID-19/complications , COVID-19/immunology , Coronavirus , Humans , Pandemics , Respiratory Tract Infections/immunology , Respiratory Tract Infections/virology , Virus Diseases/complications , Virus Diseases/immunology
4.
Immunology ; 164(1): 15-30, 2021 09.
Article in English | MEDLINE | ID: covidwho-1769724

ABSTRACT

ADP-ribosylation is the addition of one or more (up to some hundreds) ADP-ribose moieties to acceptor proteins. This evolutionary ancient post-translational modification (PTM) is involved in fundamental processes including DNA repair, inflammation, cell death, differentiation and proliferation, among others. ADP-ribosylation is catalysed by two major families of enzymes: the cholera toxin-like ADP-ribosyltransferases (ARTCs) and the diphtheria toxin-like ADP-ribosyltransferases (ARTDs, also known as PARPs). ARTCs sense and use extracellular NAD, which may represent a danger signal, whereas ARTDs are present in the cell nucleus and/or cytoplasm. ARTCs mono-ADP-ribosylate their substrates, whereas ARTDs, according to the specific family member, are able to mono- or poly-ADP-ribosylate target proteins or are devoid of enzymatic activity. Both mono- and poly-ADP-ribosylation are dynamic processes, as specific hydrolases are able to remove single or polymeric ADP moieties. This dynamic equilibrium between addition and degradation provides plasticity for fast adaptation, a feature being particularly relevant to immune cell functions. ADP-ribosylation regulates differentiation and functions of myeloid, T and B cells. It also regulates the expression of cytokines and chemokines, production of antibodies, isotype switch and the expression of several immune mediators. Alterations in these processes involve ADP-ribosylation in virtually any acute and chronic inflammatory/immune-mediated disease. Besides, pathogens developed mechanisms to contrast the action of ADP-ribosylating enzymes by using their own hydrolases and/or to exploit this PTM to sustain their virulence. In the present review, we summarize and discuss recent findings on the role of ADP-ribosylation in immunobiology, immune evasion/subversion by pathogens and immune-mediated diseases.


Subject(s)
ADP-Ribosylation/immunology , Alarmins/metabolism , Virus Diseases/immunology , Animals , Humans , Immune Evasion , Immunity, Cellular , Immunization , Inflammation , Virulence
6.
Cancer Treat Res Commun ; 31: 100537, 2022.
Article in English | MEDLINE | ID: covidwho-1693708

ABSTRACT

This overview describes the research of Nobutu Yamamoto (Philadelphia) concerning immunotherapy with GcMAF for patients with cancer and for patients infected with pathogenic envelope viruses. GcMAF (Group-specific component Macrophage-Activating Factor) is a mammalian protein with an incredible potency to directly activate macrophages. Since the late 1980s Yamamoto's investigations were published in numerous journals but in order to understand the details of his research, a minute survey of many of his patents was required. But even then, regrettably, a precise description of his experiments was sometimes lacking. This overview tries to summarize all of Yamamoto's research on GcMAF, as well as some selected more recent papers from other investigators, who tried to verify and/or reproduce Yamamoto's reports. In my opinion the most important result of the GcMAF research deserves widespread renewed attention: human GcMAF injections (100 ng per week, intramuscular or intravenous) can help to cure patients with a great variety of cancers as well as patients infected with pathogenic envelope viruses like the human immunodeficiency virus 1 (HIV-1), influenza, measles and rubella (and maybe also SARS-CoV-2). From Yamamoto's data it can be calculated that GcMAF is a near-stoichiometric activator of macrophages. Yamamoto monitored the progress of his immunotherapy via the serum level of an enzyme called nagalase (α-N-acetylgalactosaminidase activity at pH 6). I have extensively discussed the properties and potential catalytic site of this enzyme activity in an Appendix entitled: "Search for the potential active site of the latent α-N-acetylgalactosaminidase activity in the glycoproteins of some envelope viruses".


Subject(s)
Immunotherapy , Macrophage-Activating Factors , Neoplasms , Vitamin D-Binding Protein , Animals , Humans , Macrophage-Activating Factors/therapeutic use , Neoplasms/immunology , Neoplasms/therapy , Neoplasms/virology , Virus Diseases/drug therapy , Virus Diseases/immunology , Virus Diseases/virology , Vitamin D-Binding Protein/therapeutic use , alpha-N-Acetylgalactosaminidase/immunology
8.
Viruses ; 14(1)2022 01 14.
Article in English | MEDLINE | ID: covidwho-1625756

ABSTRACT

Bats are reservoirs of a large number of viruses of global public health significance, including the ancestral virus for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the causative agent of coronavirus disease 2019 (COVID-19). Although bats are natural carriers of multiple pathogenic viruses, they rarely display signs of disease. Recent insights suggest that bats have a more balanced host defense and tolerance system to viral infections that may be linked to the evolutionary adaptation to powered flight. Therefore, a deeper understanding of bat immune system may provide intervention strategies to prevent zoonotic disease transmission and to identify new therapeutic targets. Similar to other eutherian mammals, bats have both innate and adaptive immune systems that have evolved to detect and respond to invading pathogens. Bridging these two systems are innate lymphocytes, which are highly abundant within circulation and barrier tissues. These cells share the characteristics of both innate and adaptive immune cells and are poised to mount rapid effector responses. They are ideally suited as the first line of defense against early stages of viral infections. Here, we will focus on the current knowledge of innate lymphocytes in bats, their function, and their potential role in host-pathogen interactions. Moreover, given that studies into bat immune systems are often hindered by a lack of bat-specific research tools, we will discuss strategies that may aid future research in bat immunity, including the potential use of organoid models to delineate the interplay between innate lymphocytes, bat viruses, and host tolerance.


Subject(s)
Chiroptera/immunology , Host-Pathogen Interactions/immunology , Immunity, Innate/immunology , Lymphocytes/immunology , Animals , Chiroptera/virology , Disease Reservoirs/virology , Humans , Immune Tolerance , Virus Diseases/immunology , Virus Diseases/transmission , Viruses/pathogenicity
9.
Cells ; 11(2)2022 01 07.
Article in English | MEDLINE | ID: covidwho-1615837

ABSTRACT

Oxidized cholesterols, the so-called oxysterols, are widely known to regulate cholesterol homeostasis. However, more recently oxysterols have emerged as important lipid mediators in the response to both bacterial and viral infections. This review summarizes our current knowledge of selected oxysterols and their receptors in the control of intracellular bacterial growth as well as viral entry into the host cell and viral replication. Lastly, we briefly discuss the potential of oxysterols and their receptors as drug targets for infectious and inflammatory diseases.


Subject(s)
Bacterial Infections/immunology , Oxysterols/immunology , Virus Diseases/immunology , Animals , Humans
10.
Viruses ; 14(1)2021 12 30.
Article in English | MEDLINE | ID: covidwho-1613999

ABSTRACT

We acknowledge the publications for this Special Issue, "Basic Studies for Vaccine Development Targeting Virus Infections" [...].


Subject(s)
Virus Diseases/immunology , Animals , Humans , Orthomyxoviridae , Orthomyxoviridae Infections , Transcriptome , Virus Diseases/prevention & control , Zika Virus , Zika Virus Infection
12.
Int J Mol Sci ; 23(1)2021 Dec 28.
Article in English | MEDLINE | ID: covidwho-1580697

ABSTRACT

Viral infections have afflicted human health and despite great advancements in scientific knowledge and technologies, continue to affect our society today. The current coronavirus (COVID-19) pandemic has put a spotlight on the need to review the evidence on the impact of nutritional strategies to maintain a healthy immune system, particularly in instances where there are limited therapeutic treatments. Selenium, an essential trace element in humans, has a long history of lowering the occurrence and severity of viral infections. Much of the benefits derived from selenium are due to its incorporation into selenocysteine, an important component of proteins known as selenoproteins. Viral infections are associated with an increase in reactive oxygen species and may result in oxidative stress. Studies suggest that selenium deficiency alters immune response and viral infection by increasing oxidative stress and the rate of mutations in the viral genome, leading to an increase in pathogenicity and damage to the host. This review examines viral infections, including the novel SARS-CoV-2, in the context of selenium, in order to inform potential nutritional strategies to maintain a healthy immune system.


Subject(s)
SARS-CoV-2/immunology , Selenium/immunology , Selenium/pharmacology , Virus Diseases/diet therapy , Virus Diseases/immunology , Animals , Dietary Supplements , Humans , Reactive Oxygen Species/metabolism , SARS-CoV-2/drug effects , Selenium/deficiency , Selenoproteins/physiology
13.
Front Cell Infect Microbiol ; 10: 596166, 2020.
Article in English | MEDLINE | ID: covidwho-1574497

ABSTRACT

Viral infections continue to cause considerable morbidity and mortality around the world. Recent rises in these infections are likely due to complex and multifactorial external drivers, including climate change, the increased mobility of people and goods and rapid demographic change to name but a few. In parallel with these external factors, we are gaining a better understanding of the internal factors associated with viral immunity. Increasingly the gastrointestinal (GI) microbiome has been shown to be a significant player in the host immune system, acting as a key regulator of immunity and host defense mechanisms. An increasing body of evidence indicates that disruption of the homeostasis between the GI microbiome and the host immune system can adversely impact viral immunity. This review aims to shed light on our understanding of how host-microbiota interactions shape the immune system, including early life factors, antibiotic exposure, immunosenescence, diet and inflammatory diseases. We also discuss the evidence base for how host commensal organisms and microbiome therapeutics can impact the prevention and/or treatment of viral infections, such as viral gastroenteritis, viral hepatitis, human immunodeficiency virus (HIV), human papilloma virus (HPV), viral upper respiratory tract infections (URTI), influenza and SARS CoV-2. The interplay between the gastrointestinal microbiome, invasive viruses and host physiology is complex and yet to be fully characterized, but increasingly the evidence shows that the microbiome can have an impact on viral disease outcomes. While the current evidence base is informative, further well designed human clinical trials will be needed to fully understand the array of immunological mechanisms underlying this intricate relationship.


Subject(s)
Dysbiosis/virology , Microbiota/immunology , Probiotics/therapeutic use , Virus Diseases/immunology , Virus Diseases/microbiology , Animals , COVID-19/immunology , Dysbiosis/immunology , Gastrointestinal Microbiome/immunology , Host Microbial Interactions , Humans , SARS-CoV-2/isolation & purification , Viral Vaccines/administration & dosage , Viral Vaccines/immunology
14.
Viruses ; 13(12)2021 11 27.
Article in English | MEDLINE | ID: covidwho-1574265

ABSTRACT

Modulation of the antiviral innate immune response has been proposed as a putative cellular target for the development of novel pan-viral therapeutic strategies. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is especially relevant due to its essential role in the regulation of local and systemic inflammation in response to viral infections, being, therefore, a putative therapeutic target. Here, we review the extraordinary diversity of strategies that viruses have evolved to interfere with JAK-STAT signaling, stressing the relevance of this pathway as a putative antiviral target. Moreover, due to the recent remarkable progress on the development of novel JAK inhibitors (JAKi), the current knowledge on its efficacy against distinct viral infections is also discussed. JAKi have a proven efficacy against a broad spectrum of disorders and exhibit safety profiles comparable to biologics, therefore representing good candidates for drug repurposing strategies, including viral infections.


Subject(s)
Janus Kinases/metabolism , STAT Transcription Factors/metabolism , Signal Transduction/drug effects , Virus Diseases/metabolism , Viruses/metabolism , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Humans , Immunity, Innate , Inflammation , Janus Kinase Inhibitors/pharmacology , Janus Kinase Inhibitors/therapeutic use , Janus Kinases/antagonists & inhibitors , Virus Diseases/drug therapy , Virus Diseases/immunology , Viruses/classification , Viruses/drug effects
15.
Biochem J ; 478(23): 4071-4092, 2021 12 10.
Article in English | MEDLINE | ID: covidwho-1556088

ABSTRACT

The COVID-19 pandemic reminds us that in spite of the scientific progress in the past century, there is a lack of general antiviral strategies. In analogy to broad-spectrum antibiotics as antibacterial agents, developing broad spectrum antiviral agents would buy us time for the development of vaccines and treatments for future viral infections. In addition to targeting viral factors, a possible strategy is to understand host immune defense mechanisms and develop methods to boost the antiviral immune response. Here we summarize the role of NAD+-consuming enzymes in the immune defense against viral infections, with the hope that a better understanding of this process could help to develop better antiviral therapeutics targeting these enzymes. These NAD+-consuming enzymes include PARPs, sirtuins, CD38, and SARM1. Among these, the antiviral function of PARPs is particularly important and will be a focus of this review. Interestingly, NAD+ biosynthetic enzymes are also implicated in immune responses. In addition, many viruses, including SARS-CoV-2 contain a macrodomain-containing protein (NSP3 in SARS-CoV-2), which serves to counteract the antiviral function of host PARPs. Therefore, NAD+ and NAD+-consuming enzymes play crucial roles in immune responses against viral infections and detailed mechanistic understandings in the future will likely facilitate the development of general antiviral strategies.


Subject(s)
Antiviral Agents/therapeutic use , Immunity, Innate , NAD/metabolism , Virus Diseases/drug therapy , ADP-ribosyl Cyclase 1/metabolism , Armadillo Domain Proteins/metabolism , COVID-19/drug therapy , COVID-19/immunology , Cytoskeletal Proteins/metabolism , Humans , NAD/immunology , Poly (ADP-Ribose) Polymerase-1/metabolism , Protein Domains , SARS-CoV-2 , Sirtuins/metabolism , Viral Nonstructural Proteins/metabolism , Virus Diseases/immunology
16.
J Med Virol ; 93(12): 6798-6802, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1530182

ABSTRACT

Viral infections have been on the rise for the past decades. The impact of the viruses worsened amidst the pandemic burdening the already overwhelmed health care system in African countries. This article sheds light on how the coronavirus together with the already existing viral infections, some of which re-emerged, impacted the continent. The strategies in place such as immunization, education, will have to be strengthened in all African countries to reduce the burden. Furthermore, governments can further collaborate with other countries in creating guidelines to reduce co-infection of the diseases.


Subject(s)
COVID-19/enzymology , COVID-19/virology , Coinfection/epidemiology , Coinfection/virology , Virus Diseases/epidemiology , Africa/epidemiology , COVID-19/immunology , Coinfection/immunology , Humans , Pandemics/prevention & control , SARS-CoV-2/immunology , Vaccination/methods , Virus Diseases/immunology , Virus Diseases/virology
17.
PLoS Pathog ; 17(9): e1009811, 2021 09.
Article in English | MEDLINE | ID: covidwho-1526706
18.
Front Immunol ; 12: 768695, 2021.
Article in English | MEDLINE | ID: covidwho-1523709

ABSTRACT

A major barrier to human immunodeficiency virus (HIV-1) cure is the latent viral reservoir, which persists despite antiretroviral therapy (ART), including across the non-dividing myeloid reservoir which is found systemically in sanctuary sites across tissues and the central nervous system (CNS). Unlike activated CD4+ T cells that undergo rapid cell death during initial infection (due to rapid viral replication kinetics), viral replication kinetics are delayed in non-dividing myeloid cells, resulting in long-lived survival of infected macrophages and macrophage-like cells. Simultaneously, persistent inflammation in macrophages confers immune dysregulation that is a key driver of co-morbidities including cardiovascular disease (CVD) and neurological deficits in people living with HIV-1 (PLWH). Macrophage activation and dysregulation is also a key driver of disease progression across other viral infections including SARS-CoV-2, influenza, and chikungunya viruses, underscoring the interplay between macrophages and disease progression, pathogenesis, and comorbidity in the viral infection setting. This review discusses the role of macrophages in persistence and pathogenesis of HIV-1 and related comorbidities, SARS-CoV-2 and other viruses. A special focus is given to novel immunomodulatory targets for key events driving myeloid cell dysregulation and reservoir maintenance across a diverse array of viral infections.


Subject(s)
HIV Infections/immunology , Immunologic Factors/immunology , Macrophages/immunology , Virus Diseases/immunology , COVID-19/immunology , HIV-1/immunology , Humans , SARS-CoV-2/immunology
19.
J Virol ; 95(12)2021 05 24.
Article in English | MEDLINE | ID: covidwho-1501541

ABSTRACT

Long disregarded as junk DNA or genomic dark matter, endogenous retroviruses (ERVs) have turned out to represent important components of the antiviral immune response. These remnants of once-infectious retroviruses not only regulate cellular immune activation, but may even directly target invading viral pathogens. In this Gem, we summarize mechanisms by which retroviral fossils protect us from viral infections. One focus will be on recent advances in the role of ERVs as regulators of antiviral gene expression.


Subject(s)
Endogenous Retroviruses/physiology , Retroelements , Virus Diseases/immunology , Animals , Endogenous Retroviruses/genetics , Enhancer Elements, Genetic , Gene Expression Regulation , Humans , Immunity, Cellular , Promoter Regions, Genetic , RNA, Double-Stranded/genetics , RNA, Double-Stranded/metabolism , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , RNA, Viral/genetics , RNA, Viral/metabolism , Receptors, Pattern Recognition/metabolism , Receptors, Virus/antagonists & inhibitors , Receptors, Virus/metabolism , Viral Proteins/metabolism , Virion/metabolism , Virus Diseases/genetics , Virus Diseases/virology
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