scholarly journals The Innate Antiviral Response in Animals: An Evolutionary Perspective from Flagellates to Humans

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 758 ◽  
Author(s):  
Karim Majzoub ◽  
Florian Wrensch ◽  
Thomas F. Baumert
Keyword(s):  
Viral Infections ◽  
Current Knowledge ◽  
Innate Immune ◽  
Model Organisms ◽  
Animal Cells ◽  
Molecular Systems ◽  
Host Interactions ◽  
Animal Hosts ◽  
Immune Pathways ◽  
Innate Antiviral Response

Animal cells have evolved dedicated molecular systems for sensing and delivering a coordinated response to viral threats. Our understanding of these pathways is almost entirely defined by studies in humans or model organisms like mice, fruit flies and worms. However, new genomic and functional data from organisms such as sponges, anemones and mollusks are helping redefine our understanding of these immune systems and their evolution. In this review, we will discuss our current knowledge of the innate immune pathways involved in sensing, signaling and inducing genes to counter viral infections in vertebrate animals. We will then focus on some central conserved players of this response including Toll-like receptors (TLRs), RIG-I-like receptors (RLRs) and cGAS-STING, attempting to put their evolution into perspective. To conclude, we will reflect on the arms race that exists between viruses and their animal hosts, illustrated by the dynamic evolution and diversification of innate immune pathways. These concepts are not only important to understand virus-host interactions in general but may also be relevant for the development of novel curative approaches against human disease.

scholarly journals The L1-dependant and Pol III transcribed Alu retrotransposon, from its discovery to innate immunity

2021 ◽  
Vol 48 (3) ◽  
pp. 2775-2789
Author(s):  
Ludwig Stenz
Keyword(s):  
Human Genome ◽  
Viral Infections ◽  
De Novo ◽  
Current Knowledge ◽  
Innate Immune ◽  
De Novo Mutation ◽  
Neuronal Diversity ◽  
Alu Sequences ◽  
Pol Iii ◽  
The Brain

AbstractThe 300 bp dimeric repeats digestible by AluI were discovered in 1979. Since then, Alu were involved in the most fundamental epigenetic mechanisms, namely reprogramming, pluripotency, imprinting and mosaicism. These Alu encode a family of retrotransposons transcribed by the RNA Pol III machinery, notably when the cytosines that constitute their sequences are de-methylated. Then, Alu hijack the functions of ORF2 encoded by another transposons named L1 during reverse transcription and integration into new sites. That mechanism functions as a complex genetic parasite able to copy-paste Alu sequences. Doing that, Alu have modified even the size of the human genome, as well as of other primate genomes, during 65 million years of co-evolution. Actually, one germline retro-transposition still occurs each 20 births. Thus, Alu continue to modify our human genome nowadays and were implicated in de novo mutation causing diseases including deletions, duplications and rearrangements. Most recently, retrotransposons were found to trigger neuronal diversity by inducing mosaicism in the brain. Finally, boosted during viral infections, Alu clearly interact with the innate immune system. The purpose of that review is to give a condensed overview of all these major findings that concern the fascinating physiology of Alu from their discovery up to the current knowledge.

scholarly journals Canonical and Noncanonical Autophagy as Potential Targets for COVID-19

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1619 ◽  
Author(s):  
Melissa Bello-Perez ◽  
Isabel Sola ◽  
Beatriz Novoa ◽  
Daniel J. Klionsky ◽  
Alberto Falco
Keyword(s):  
Molecular Mechanisms ◽  
Viral Infections ◽  
Current Knowledge ◽  
Therapeutic Targets ◽  
Innate Immune ◽  
Interacting Proteins ◽  
Innate Immune Responses ◽  
Molecular Machinery ◽  
Autophagy Pathway

The SARS-CoV-2 pandemic necessitates a review of the molecular mechanisms underlying cellular infection by coronaviruses, in order to identify potential therapeutic targets against the associated new disease (COVID-19). Previous studies on its counterparts prove a complex and concomitant interaction between coronaviruses and autophagy. The precise manipulation of this pathway allows these viruses to exploit the autophagy molecular machinery while avoiding its protective apoptotic drift and cellular innate immune responses. In turn, the maneuverability margins of such hijacking appear to be so narrow that the modulation of the autophagy, regardless of whether using inducers or inhibitors (many of which are FDA-approved for the treatment of other diseases), is usually detrimental to viral replication, including SARS-CoV-2. Recent discoveries indicate that these interactions stretch into the still poorly explored noncanonical autophagy pathway, which might play a substantial role in coronavirus replication. Still, some potential therapeutic targets within this pathway, such as RAB9 and its interacting proteins, look promising considering current knowledge. Thus, the combinatory treatment of COVID-19 with drugs affecting both canonical and noncanonical autophagy pathways may be a turning point in the fight against this and other viral infections, which may also imply beneficial prospects of long-term protection.

Mitochondria—Striking a balance between host and endosymbiont

Science ◽  
2019 ◽  
Vol 365 (6454) ◽  
pp. eaaw9855 ◽  
Author(s):  
Richard J. Youle
Keyword(s):  
Gene Expression ◽  
Quality Control ◽  
Energy Production ◽  
Viral Infections ◽  
Nuclear Genome ◽  
Innate Immune ◽  
Mitochondrial Genomes ◽  
Proteotoxic Stress ◽  
Immune Pathways ◽  
Mutational Meltdown

Mitochondria are organelles with their own genome that arose from α-proteobacteria living within single-celled Archaea more than a billion years ago. This step of endosymbiosis offered tremendous opportunities for energy production and metabolism and allowed the evolution of fungi, plants, and animals. However, less appreciated are the downsides of this endosymbiosis. Coordinating gene expression between the mitochondrial genomes and the nuclear genome is imprecise and can lead to proteotoxic stress. The clonal reproduction of mitochondrial DNA requires workarounds to avoid mutational meltdown. In metazoans that developed innate immune pathways to thwart bacterial and viral infections, mitochondrial components can cross-react with pathogen sensors and invoke inflammation. Here, I focus on the numerous and elegant quality control processes that compensate for or mitigate these challenges of endosymbiosis.

scholarly journals Phagocytosis, Degranulation and Extracellular Traps Release by Neutrophils—The Current Knowledge, Pharmacological Modulation and Future Prospects

2021 ◽  
Vol 12 ◽  
Author(s):  
Barbara Gierlikowska ◽  
Albert Stachura ◽  
Wojciech Gierlikowski ◽  
Urszula Demkow
Keyword(s):  
Molecular Mechanisms ◽  
Viral Infections ◽  
Current Knowledge ◽  
Innate Immune ◽  
Therapeutic Approaches ◽  
Effector Functions ◽  
Pharmacological Modulation ◽  
Synthetic Drugs ◽  
Extracellular Traps

Neutrophils are crucial elements of innate immune system, which assure host defense via a range of effector functions, such as phagocytosis, degranulation, and NET formation. The latest literature clearly indicates that modulation of effector functions of neutrophils may affect the treatment efficacy. Pharmacological modulation may affect molecular mechanisms activating or suppressing phagocytosis, degranulation or NET formation. In this review, we describe the role of neutrophils in physiology and in the course of bacterial and viral infections, illustrating the versatility and plasticity of those cells. This review also focus on the action of plant extracts, plant-derived compounds and synthetic drugs on effector functions of neutrophils. These recent advances in the knowledge can help to devise novel therapeutic approaches via pharmacological modulation of the described processes.

scholarly journals Immunity and Viral Infections: Modulating Antiviral Response via CRISPR–Cas Systems

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1373
Author(s):  
Sergey Brezgin ◽  
Anastasiya Kostyusheva ◽  
Ekaterina Bayurova ◽  
Elena Volchkova ◽  
Vladimir Gegechkori ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Immune Responses ◽  
Viral Infections ◽  
Antiviral Agents ◽  
Innate Immune ◽  
Host Factors ◽  
Innate Immune Responses ◽  
Host Interactions ◽  
Translational Studies ◽  
Short Time

Viral infections cause a variety of acute and chronic human diseases, sometimes resulting in small local outbreaks, or in some cases spreading across the globe and leading to global pandemics. Understanding and exploiting virus–host interactions is instrumental for identifying host factors involved in viral replication, developing effective antiviral agents, and mitigating the severity of virus-borne infectious diseases. The diversity of CRISPR systems and CRISPR-based tools enables the specific modulation of innate immune responses and has contributed impressively to the fields of virology and immunology in a very short time. In this review, we describe the most recent advances in the use of CRISPR systems for basic and translational studies of virus–host interactions.

scholarly journals JAK-STAT Pathway: A Novel Target to Tackle Viral Infections

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2379
Author(s):  
Ifeanyi Jude Ezeonwumelu ◽  
Edurne Garcia-Vidal ◽  
Ester Ballana
Keyword(s):  
Viral Infections ◽  
Current Knowledge ◽  
Drug Repurposing ◽  
Innate Immune ◽  
Janus Kinase ◽  
Cellular Target ◽  
Proven Efficacy ◽  
Novel Target ◽  
Remarkable Progress ◽  
Stat Pathway

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.

scholarly journals Viperin Reveals Its True Function

2020 ◽  
Vol 7 (1) ◽  
pp. 421-446 ◽  
Author(s):  
Efraín E. Rivera-Serrano ◽  
Anthony S. Gizzi ◽  
Jamie J. Arnold ◽  
Tyler L. Grove ◽  
Steven C. Almo ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Enzymatic Activity ◽  
Rna Synthesis ◽  
Viral Infections ◽  
Innate Immune ◽  
Biological Functions ◽  
Restriction Factors ◽  
Rna Dependent Rna Polymerase ◽  
Immune Pathways ◽  
Antiviral Mechanism

Most cells respond to viral infections by activating innate immune pathways that lead to the induction of antiviral restriction factors. One such factor, viperin, was discovered almost two decades ago based on its induction during viral infection. Since then, viperin has been shown to possess activity against numerous viruses via multiple proposed mechanisms. Most recently, however, viperin was demonstrated to catalyze the conversion of cytidine triphosphate (CTP) to 3′-deoxy-3′,4′-didehydro-CTP (ddhCTP), a previously unknown ribonucleotide. Incorporation of ddhCTP causes premature termination of RNA synthesis by the RNA-dependent RNA polymerase of some viruses. To date, production of ddhCTP by viperin represents the only activity of viperin that links its enzymatic activity directly to an antiviral mechanism in human cells. This review examines the multiple antiviral mechanisms and biological functions attributed to viperin.

scholarly journals The missing link: does tunnelling nanotube-based supercellularity provide a new understanding of chronic and lifestyle diseases?

Open Biology ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 160057 ◽  
Author(s):  
Amin Rustom
Keyword(s):  
Neurodegenerative Disorders ◽  
Viral Infections ◽  
Current Knowledge ◽  
Stem Cell Differentiation ◽  
Stress Factors ◽  
Pathological State ◽  
Animal Cells ◽  
Cellular Mechanisms ◽  
Link Type ◽  
Field Of Vision

Tunnelling nanotubes (TNTs) are increasingly recognized as central players in a multitude of cellular mechanisms and diseases. Although their existence and functions in animal organisms are still elusive, emerging evidence suggests that they are involved in developmental processes, tissue regeneration, viral infections or pathogen transfer, stem cell differentiation, immune responses as well as initiation and progression of neurodegenerative disorders and cancer (see Sisakhtnezhad & Khosravi 2015 Eur. J. Cell Biol. 94, 429–443. ( doi:10.1016/j.ejcb.2015.06.010 )). A broader field of vision, including their striking functional and structural resemblance with nanotube-mediated phenomena found throughout the phylogenetic tree, from plants down to bacteria, points to a universal, conserved and tightly regulated mechanism of cellular assemblies. Based on our initial definition of TNTs as open-ended channels mediating membrane continuity between connected cells (Rustom et al. 2004 Science 303, 1007–1010. ( doi:10.1126/science.1093133 )), it is suggested that animal tissues represent supercellular assemblies that—besides opening discrete communication pathways—balance diverse stress factors caused by pathological changes or fluctuating physiological and environmental conditions, such as oxidative stress or nutrient shortage. By combining current knowledge about nanotube formation, intercellular transfer and communication phenomena as well as associated molecular pathways, a model evolves, predicting that the linkage between reactive oxygen species, TNT-based supercellularity and the intercellular shuttling of materials will have significant impact on diverse body functions, such as cell survival, redox/metabolic homeostasis and mitochondrial heteroplasmy. It implies that TNTs are intimately linked to the physiological and pathological state of animal cells and represent a central joint element of diverse diseases, such as neurodegenerative disorders, diabetes or cancer.

The glycomes of Caenorhabditis elegans and other model organisms

2002 ◽  
Vol 69 ◽  
pp. 117-134 ◽  
Author(s):  
Stuart M. Haslam ◽  
David Gems ◽  
Howard R. Morris ◽  
Anne Dell
Keyword(s):  
Caenorhabditis Elegans ◽  
Current Knowledge ◽  
Structural Data ◽  
Model Organisms ◽  
Entire Genome ◽  
C Elegans ◽  
The Face ◽  
Area Of Concern ◽  
Nematode Worm

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.

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