scholarly journals How fragile we are. Influence of STimulator of INterferon Genes, STING, variants on pathogen recognition and immune response efficiency

2021 ◽  
Author(s):  
Jeremy Morere ◽  
Cecilia Hognon ◽  
Tom Miclot ◽  
Tao Jiang ◽  
Elise Dumont ◽  
...  
Keyword(s):  
Immune Response ◽  
Molecular Mechanisms ◽  
Viral Infections ◽  
Inflammatory Diseases ◽  
Dynamical Behavior ◽  
Structural Features ◽  
Type I Interferons ◽  
Machine Learning Techniques ◽  
Type I ◽  
Interaction Patterns

The STimulator of INterferon Genes (STING) protein is a cornerstone of the human immune response. Its activation by cGAMP upon the presence of cytosolic DNA stimulates the production of type I interferons and inflammatory cytokines which are crucial for protecting cells from infections. STING signaling pathway can also influence both tumor-suppressive and tumor-promoting mechanisms, rendering it an appealing target for drug design. In the human population, several STING variants exist and exhibit dramatic differences in their activity, impacting the efficiency of the host defense against infections. Understanding the differential molecular mechanisms exhibited by these variants is of utmost importance notably towards personalized medicine treatments against diseases such as viral infections (COVID-19, Dengue...), cancers, or auto-inflammatory diseases. Owing to micro-seconds scale molecular modeling simulations and post-processing by contacts analysis and Machine Learning techniques, we reveal the dynamical behavior of four STING variants (wild type, G230A, R293Q, and G230A-R293Q) and we rationalize the variability of efficiency observed experimentally. Our results show that the decrease of STING activity is linked to a stiffening of key-structural features of the binding cavity, together with changes of the interaction patterns within the protein.

scholarly journals Human Type I Interferon Antiviral Effects in Respiratory and Reemerging Viral Infections

2020 ◽  
Vol 2020 ◽  
pp. 1-27 ◽  
Author(s):  
Patricio L. Acosta ◽  
Alana B. Byrne ◽  
Diego R. Hijano ◽  
Laura B. Talarico
Keyword(s):  
Immune System ◽  
Host Defense ◽  
Immune Modulation ◽  
Molecular Mechanisms ◽  
Viral Infections ◽  
Current Knowledge ◽  
Type I Interferons ◽  
Type I ◽  
Antiviral Effects ◽  
Wide Range

Type I interferons (IFN-I) are a group of related proteins that help regulate the activity of the immune system and play a key role in host defense against viral infections. Upon infection, the IFN-I are rapidly secreted and induce a wide range of effects that not only act upon innate immune cells but also modulate the adaptive immune system. While IFN-I and many IFN stimulated genes are well-known for their protective antiviral role, recent studies have associated them with potential pathogenic functions. In this review, we summarize the current knowledge regarding the complex effects of human IFN-I responses in respiratory as well as reemerging flavivirus infections of public health significance and the molecular mechanisms by which viral proteins antagonize the establishment of an antiviral host defense. Antiviral effects and immune modulation of IFN-stimulated genes is discussed in resisting and controlling pathogens. Understanding the mechanisms of these processes will be crucial in determining how viral replication can be effectively controlled and in developing safe and effective vaccines and novel therapeutic strategies.

scholarly journals When human guanylate-binding proteins meet viral infections

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Rongzhao Zhang ◽  
Zhixin Li ◽  
Yan-Dong Tang ◽  
Chenhe Su ◽  
Chunfu Zheng
Keyword(s):  
Innate Immunity ◽  
Viral Infection ◽  
Binding Proteins ◽  
Molecular Mechanisms ◽  
Viral Infections ◽  
Innate Immune ◽  
Type I Interferons ◽  
Type I ◽  
Downstream Signaling ◽  
Antiviral Innate Immunity

AbstractInnate immunity is the first line of host defense against viral infection. After invading into the cells, pathogen-associated-molecular-patterns derived from viruses are recognized by pattern recognition receptors to activate the downstream signaling pathways to induce the production of type I interferons (IFN-I) and inflammatory cytokines, which play critical functions in the host antiviral innate immune responses. Guanylate-binding proteins (GBPs) are IFN-inducible antiviral effectors belonging to the guanosine triphosphatases family. In addition to exerting direct antiviral functions against certain viruses, a few GBPs also exhibit regulatory roles on the host antiviral innate immunity. However, our understanding of the underlying molecular mechanisms of GBPs' roles in viral infection and host antiviral innate immune signaling is still very limited. Therefore, here we present an updated overview of the functions of GBPs during viral infection and in antiviral innate immunity, and highlight discrepancies in reported findings and current challenges for future studies, which will advance our understanding of the functions of GBPs and provide a scientific and theoretical basis for the regulation of antiviral innate immunity.

scholarly journals SLC19A1 is a cyclic dinucleotide transporter

2019 ◽  
Author(s):  
Rutger D. Luteijn ◽  
Shivam A. Zaver ◽  
Benjamin G. Gowen ◽  
Stacia Wyman ◽  
Nick Garelis ◽  
...  
Keyword(s):  
Immune Response ◽  
Ex Vivo ◽  
Inflammatory Diseases ◽  
Type I Interferons ◽  
Target Cells ◽  
Type I ◽  
Functional Responses ◽  
A Genome ◽  
Sting Pathway ◽  
Cyclic Dinucleotide

The accumulation of DNA in the cytosol serves as a key immunostimulatory signal associated with infections, cancer and genomic damage1,2. Cytosolic DNA triggers immune responses by activating the cGAS/STING pathway3. The binding of DNA to the cytosolic enzyme cGAMP synthase (cGAS), activates its enzymatic activity, leading to the synthesis of a second messenger, cyclic[G(2’,5’)pA(3’,5’)] (2’3’-cGAMP)4–8. 2’3’-cGAMP, a cyclic dinucleotide (CDN), activates the protein ‘stimulator of interferon genes’ (STING)9, which in turn activates the transcription factors IRF3 and NF-κB promoting the transcription of genes encoding type I interferons and other cytokines and mediators that stimulate a broader immune response. Exogenous 2’3’-cGAMP and other CDNs, including CDNs produced by bacteria and synthetic CDNs used in cancer immunotherapy, must traverse the cell membrane to activate STING in target cells. How these charged CDNs pass through the lipid bilayer is unknown. Here we used a genome-wide CRISPR interference screen to identify the reduced folate carrier SLC19A1 as the major CDN transporter for uptake of synthetic and naturally occurring CDNs. CDN uptake and functional responses are inhibited by depleting SLC19A1 from cells and enhanced by overexpressing SLC19A1. In both cell lines and primary cells ex vivo, CDN uptake is inhibited competitively by folate and blocked by the SLC19A1 inhibitor sulfasalazine, a medication approved for the treatment of inflammatory diseases. The identification of SLC19A1 as the major transporter of CDNs into cells has far reaching implications for the immunotherapeutic treatment of cancer10, transport of 2’3’-cGAMP from tumor cells to other immune cells to trigger the anti-tumor immune response11, host responsiveness to CDN-producing pathogenic microorganisms12, and potentially in certain inflammatory diseases.

scholarly journals Type I Interferon at the Interface of Antiviral Immunity and Immune Regulation: The Curious Case of HIV-1

Scientifica ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-20 ◽  
Author(s):  
Adriano Boasso
Keyword(s):  
Immune Response ◽  
Molecular Mechanisms ◽  
Viral Infections ◽  
Type I Interferon ◽  
Critical Role ◽  
Antiviral Immunity ◽  
Target Cells ◽  
Type I ◽  
Cell Immunity ◽  
Hiv 1

Type I interferon (IFN-I) play a critical role in the innate immune response against viral infections. They actively participate in antiviral immunity by inducing molecular mechanisms of viral restriction and by limiting the spread of the infection, but they also orchestrate the initial phases of the adaptive immune response and influence the quality of T cell immunity. During infection with the human immunodeficiency virus type 1 (HIV-1), the production of and response to IFN-I may be severely altered by the lymphotropic nature of the virus. In this review I consider the different aspects of virus sensing, IFN-I production, signalling, and effects on target cells, with a particular focus on the alterations observed following HIV-1 infection.

scholarly journals Complexities of Type I Interferon Biology: Lessons from LCMV

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 172 ◽  
Author(s):  
Tamara Suprunenko ◽  
Markus Hofer
Keyword(s):  
Molecular Mechanisms ◽  
Viral Infections ◽  
Type I Interferon ◽  
Malignant Tumors ◽  
Antiviral Immunity ◽  
Lymphocytic Choriomeningitis ◽  
Type I Interferons ◽  
Host Responses ◽  
Type I ◽  
Novel Treatments

Over the past decades, infection of mice with lymphocytic choriomeningitis virus (LCMV) has provided an invaluable insight into our understanding of immune responses to viruses. In particular, this model has clarified the central roles that type I interferons play in initiating and regulating host responses. The use of different strains of LCMV and routes of infection has allowed us to understand how type I interferons are critical in controlling virus replication and fostering effective antiviral immunity, but also how they promote virus persistence and functional exhaustion of the immune response. Accordingly, these discoveries have formed the foundation for the development of novel treatments for acute and chronic viral infections and even extend into the management of malignant tumors. Here we review the fundamental insights into type I interferon biology gained using LCMV as a model and how the diversity of LCMV strains, dose, and route of administration have been used to dissect the molecular mechanisms underpinning acute versus persistent infection. We also identify gaps in the knowledge regarding LCMV regulation of antiviral immunity. Due to its unique properties, LCMV will continue to remain a vital part of the immunologists’ toolbox.

scholarly journals How dendritic cells sense and respond to viral infections

2021 ◽  
Vol 135 (19) ◽  
pp. 2217-2242
Author(s):  
Laura Marongiu ◽  
Mihai Valache ◽  
Fabio A. Facchini ◽  
Francesca Granucci
Keyword(s):  
Immune Response ◽  
Dendritic Cells ◽  
Viral Infections ◽  
Adaptive Immune Response ◽  
Type I Interferons ◽  
Type I ◽  
Viral Pathogens ◽  
Cross Presentation ◽  
Antiviral Responses ◽  
Sense And Respond

Abstract The ability of dendritic cells (DCs) to sense viral pathogens and orchestrate a proper immune response makes them one of the key players in antiviral immunity. Different DC subsets have complementing functions during viral infections, some specialize in antigen presentation and cross-presentation and others in the production of cytokines with antiviral activity, such as type I interferons. In this review, we summarize the latest updates concerning the role of DCs in viral infections, with particular focus on the complex interplay between DC subsets and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Despite being initiated by a vast array of immune receptors, DC-mediated antiviral responses often converge towards the same endpoint, that is the production of proinflammatory cytokines and the activation of an adaptive immune response. Nonetheless, the inherent migratory properties of DCs make them a double-edged sword and often viral recognition by DCs results in further viral dissemination. Here we illustrate these various aspects of the antiviral functions of DCs and also provide a brief overview of novel antiviral vaccination strategies based on DCs targeting.

scholarly journals In VivoConditions Enable IFNAR-Independent Type I Interferon Production by Peritoneal CD11b+Cells upon Thogoto Virus Infection

2016 ◽  
Vol 90 (20) ◽  
pp. 9330-9337 ◽  
Author(s):  
Georg Kochs ◽  
Martina Anzaghe ◽  
Stefanie Kronhart ◽  
Valentina Wagner ◽  
Patricia Gogesch ◽  
...  
Keyword(s):  
Virus Infection ◽  
Positive Feedback ◽  
Molecular Mechanisms ◽  
Viral Infections ◽  
Type I Interferons ◽  
Type I ◽  
Type I Ifn ◽  
Cell Type ◽  
Type I Ifns

ABSTRACTType I interferons (IFNs) crucially contribute to host survival upon viral infections. Robust expression of type I IFNs (IFN-α/β) and induction of an antiviral state critically depend on amplification of the IFN signal via the type I IFN receptor (IFNAR). A small amount of type I IFN produced early upon virus infection binds the IFNAR and activates a self-enhancing positive feedback loop, resulting in induction of large, protective amounts of IFN-α. Unexpectedly, we found robust, systemic IFN-α expression upon infection of IFNAR knockout mice with the orthomyxovirus Thogoto virus (THOV). The IFNAR-independent IFN-α production requiredin vivoconditions and was not achieved duringin vitroinfection. Using replication-incompetent THOV-derived virus-like particles, we demonstrate that IFNAR-independent type I IFN induction depends on viral polymerase activity but is largely independent of viral replication. To discover the cell type responsible for this effect, we used type I IFN reporter mice and identified CD11b+F4/80+myeloid cells within the peritoneal cavity of infected animals as the main source of IFNAR-independent type I IFN, corresponding to the particular tropism of THOV for this cell type.IMPORTANCEType I IFNs are crucial for the survival of a host upon most viral infections, and, moreover, they shape subsequent adaptive immune responses. Production of protective amounts of type I IFN critically depends on the positive feedback amplification via the IFNAR. Unexpectedly, we observed robust IFNAR-independent type I IFN expression upon THOV infection and unraveled molecular mechanisms and determined the tissue and cell type involved. Our data indicate that the host can effectively use alternative pathways to induce type I IFN responses if the classical feedback amplification is not available. Understanding how type I IFN can be produced in large amounts independently of IFNAR-dependent enhancement will identify mechanisms which might contribute to novel therapeutic strategies to fight viral pathogens.

scholarly journals Getting on in Old Age: How the Gut Microbiota Interferes With Brain Innate Immunity

2021 ◽  
Vol 15 ◽  
Author(s):  
Omar Mossad ◽  
Thomas Blank
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Immune System ◽  
Gut Microbiota ◽  
Inflammatory Diseases ◽  
Cell Types ◽  
Innate Immune ◽  
Type I Interferons ◽  
Type I ◽  
Age Related

The immune system is crucial for defending against various invaders, such as pathogens, cancer cells or misfolded proteins. With increasing age, the diminishing immune response, known as immunosenescence, becomes evident. Concomitantly, some diseases like infections, autoimmune diseases, chronic inflammatory diseases and cancer, accumulate with age. Different cell types are part of the innate immunity response and produce soluble factors, cytokines, chemokines, and type I interferons. Improper maturation of innate immune cells or their dysfunction have been linked to numerous age-related diseases. In parallel to the occurrence of the many functional facets of the immune response, a symbiotic microbiota had been acquired. For the relevant and situation-dependent function of the immune system the microbiome plays an essential role because it fine-tunes the immune system and its responses during life. Nevertheless, how the age-related alterations in the microbiota are reflected in the innate immune system, is still poorly understood. With this review, we provide an up-to-date overview on our present understanding of the gut microbiota effects on innate immunity, with a particular emphasis on aging-associated changes in the gut microbiota and the implications for the brain innate immune response.

scholarly journals Bacterial Cyclic Dinucleotides and the cGAS–cGAMP–STING Pathway: A Role in Periodontitis?

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 675
Author(s):  
Samira Elmanfi ◽  
Mustafa Yilmaz ◽  
Wilson W. S. Ong ◽  
Kofi S. Yeboah ◽  
Herman O. Sintim ◽  
...  
Keyword(s):  
Immune Response ◽  
Periodontal Disease ◽  
Innate Immune ◽  
Host Cells ◽  
Type I Interferons ◽  
Type I ◽  
Vaccine Adjuvants ◽  
Cyclic Dinucleotides ◽  
Sting Pathway

Host cells can recognize cytosolic double-stranded DNAs and endogenous second messengers as cyclic dinucleotides—including c-di-GMP, c-di-AMP, and cGAMP—of invading microbes via the critical and essential innate immune signaling adaptor molecule known as STING. This recognition activates the innate immune system and leads to the production of Type I interferons and proinflammatory cytokines. In this review, we (1) focus on the possible role of bacterial cyclic dinucleotides and the STING/TBK1/IRF3 pathway in the pathogenesis of periodontal disease and the regulation of periodontal immune response, and (2) review and discuss activators and inhibitors of the STING pathway as immune response regulators and their potential utility in the treatment of periodontitis. PubMed/Medline, Scopus, and Web of Science were searched with the terms “STING”, “TBK 1”, “IRF3”, and “cGAS”—alone, or together with “periodontitis”. Current studies produced evidence for using STING-pathway-targeting molecules as part of anticancer therapy, and as vaccine adjuvants against microbial infections; however, the role of the STING/TBK1/IRF3 pathway in periodontal disease pathogenesis is still undiscovered. Understanding the stimulation of the innate immune response by cyclic dinucleotides opens a new approach to host modulation therapies in periodontology.

scholarly journals CD169/SIGLEC1 is expressed on circulating monocytes in COVID-19 and expression levels are associated with disease severity

Infection ◽  
2021 ◽  
Author(s):  
Jan-Moritz Doehn ◽  
Christoph Tabeling ◽  
Robert Biesen ◽  
Jacopo Saccomanno ◽  
Elena Madlung ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Disease Severity ◽  
Clinical Studies ◽  
Viral Infections ◽  
Severe Disease ◽  
Type I Interferons ◽  
Type I ◽  
Interferon Signaling ◽  
Expression Levels

AbstractCoronavirus disease 2019 (COVID-19) is caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Type I interferons are important in the defense of viral infections. Recently, neutralizing IgG auto-antibodies against type I interferons were found in patients with severe COVID-19 infection. Here, we analyzed expression of CD169/SIGLEC1, a well described downstream molecule in interferon signaling, and found increased monocytic CD169/SIGLEC1 expression levels in patients with mild, acute COVID-19, compared to patients with severe disease. We recommend further clinical studies to evaluate the value of CD169/SIGLEC1 expression in patients with COVID-19 with or without auto-antibodies against type I interferons.

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