scholarly journals Inhibition of retrotransposition improves health and extends lifespan of SIRT6 knockout mice

2018 ◽  
Author(s):  
Matthew Simon ◽  
Michael Van Meter ◽  
Julia Ablaeva ◽  
Zhonghe Ke ◽  
Raul S. Gonzalez ◽  
...  
Keyword(s):  
Dna Damage ◽  
Reverse Transcriptase ◽  
Knockout Mice ◽  
Type I Interferon ◽  
Display Type ◽  
Interferon Response ◽  
Type I ◽  
Wild Type ◽  
Reverse Transcriptase Inhibitors ◽  
Aged Mice

SUMMARYMice deficient for SIRT6 exhibit a severely shortened lifespan, growth retardation, and highly elevated LINE1 (L1) activity. Here we report that SIRT6 deficient cells and tissues accumulate abundant cytoplasmic L1 cDNA which triggers massive type I interferon response via activation of cGAS. Remarkably, nucleoside reverse transcriptase inhibitors (NRTIs), which inhibit L1 retrotransposition, significantly improved health and lifespan of SIRT6 knockout mice and completely rescued type I interferon response. In tissue culture, inhibition of L1 with siRNA or NRTIs abrogated type I interferon response, in addition to a significant reduction of DNA damage markers. These results indicate that L1 activation contributes to the pathologies of SIRT6 knockout mice. Similarly, L1 transcription, cytoplasmic cDNA copy number and type I interferons were elevated in the wild type aged mice. As sterile inflammation is a hallmark of aging we propose that modulating L1 activity may be an important strategy for attenuating age-related pathologies.HighlightsSIRT6 KO mice accumulate L1 cDNA triggering type I interferon response via cGAS pathwayWild type aged mice accumulate L1 cDNA and display type I interferon responseReverse transcriptase inhibitors rescue type I interferon response and DNA damageReverse transcriptase inhibitors extend lifespan and improve health of SIRT6 KO mice

scholarly journals A paucigranulocytic asthma host environment promotes the emergence of virulent influenza viral variants

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Katina D Hulme ◽  
Anjana C Karawita ◽  
Cassandra Pegg ◽  
Myrna JM Bunte ◽  
Helle Bielefeldt-Ohmann ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Disease Severity ◽  
Type I Interferon ◽  
Polymerase Activity ◽  
Interferon Response ◽  
Type I ◽  
Interferon Production ◽  
Wild Type ◽  
Host Environment ◽  
Severe Influenza

Influenza virus has a high mutation rate, such that within one host different viral variants can emerge. Evidence suggests that influenza virus variants are more prevalent in pregnant and/or obese individuals due to their impaired interferon response. We have recently shown that the non-allergic, paucigranulocytic subtype of asthma is associated with impaired type I interferon production. Here, we seek to address if this is associated with an increased emergence of influenza virus variants. Compared to controls, mice with paucigranulocytic asthma had increased disease severity and an increased emergence of influenza virus variants. Specifically, PB1 mutations exclusively detected in asthmatic mice were associated with increased polymerase activity. Furthermore, asthmatic host-derived virus led to increased disease severity in wild-type mice. Taken together, these data suggest that at least a subset of patients with asthma may be more susceptible to severe influenza and may be a possible source of new influenza virus variants.

scholarly journals The Interferon-Induced Exonuclease ISG20 Exerts Antiviral Activity through Upregulation of Type I Interferon Response Proteins

mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Christopher M. Weiss ◽  
Derek W. Trobaugh ◽  
Chengqun Sun ◽  
Tiffany M. Lucas ◽  
Michael S. Diamond ◽  
...  
Keyword(s):  
Virus Replication ◽  
Type I Interferon ◽  
Rna Virus ◽  
Ectopic Expression ◽  
Viral Rna ◽  
Interferon Response ◽  
Type I ◽  
Venezuelan Equine Encephalitis ◽  
Wild Type ◽  
In Cells

ABSTRACTType I interferon (IFN)-stimulated genes (ISGs) have critical roles in inhibiting virus replication and dissemination. Despite advances in understanding the molecular basis of ISG restriction, the antiviral mechanisms of many remain unclear. The 20-kDa ISG ISG20 is a nuclear 3′–5′ exonuclease with preference for single-stranded RNA (ssRNA) and has been implicated in the IFN-mediated restriction of several RNA viruses. Although the exonuclease activity of ISG20 has been shown to degrade viral RNAin vitro, evidence has yet to be presented that virus inhibition in cells requires this activity. Here, we utilized a combination of an inducible, ectopic expression system and newly generatedIsg20−/−mice to investigate mechanisms and consequences of ISG20-mediated restriction. Ectopically expressed ISG20 localized primarily to Cajal bodies in the nucleus and restricted replication of chikungunya and Venezuelan equine encephalitis viruses. Although restriction by ISG20 was associated with inhibition of translation of infecting genomic RNA, degradation of viral RNAs was not observed. Instead, translation inhibition of viral RNA was associated with ISG20-induced upregulation of over 100 other genes, many of which encode known antiviral effectors. ISG20 modulated the production of IFIT1, an ISG that suppresses translation of alphavirus RNAs. Consistent with this observation, the pathogenicity of IFIT1-sensitive alphaviruses was increased inIsg20−/−mice compared to that of wild-type viruses but not in cells ectopically expressing ISG20. Our findings establish an indirect role for ISG20 in the early restriction of RNA virus replication by regulating expression of other ISGs that inhibit translation and possibly other activities in the replication cycle.IMPORTANCEThe host immune responses to infection lead to the production of type I interferon (IFN), and the upregulation of interferon-stimulated genes (ISGs) reduces virus replication and virus dissemination within a host. Ectopic expression of the interferon-induced 20-kDa exonuclease ISG20 suppressed replication of chikungunya virus and Venezuelan equine encephalitis virus, two mosquito-vectored RNA alphaviruses. Since the replication of alphavirus genomes occurs exclusively in the cytoplasm, the mechanism of nucleus-localized ISG20 inhibition of replication is unclear. In this study, we determined that ISG20 acts as a master regulator of over 100 genes, many of which are ISGs. Specifically, ISG20 upregulated IFIT1 genes and inhibited translation of the alphavirus genome. Furthermore, IFIT1-sensitive alphavirus replication was increased inIsg20−/−mice compared to the replication of wild-type viruses but not in cells ectopically expressing ISG20. We propose that ISG20 acts as an indirect regulator of RNA virus replication in the cytoplasm through the upregulation of many other ISGs.

scholarly journals The LymphotoxinβReceptor Is Essential for Upregulation of IFN-Induced Guanylate-Binding Proteins and Survival afterToxoplasma gondiiInfection

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Kristina Behnke ◽  
Ursula R. Sorg ◽  
Helmut E. Gabbert ◽  
Klaus Pfeffer
Keyword(s):  
Type I Interferon ◽  
Parasite Load ◽  
Mortality Rates ◽  
Host Responses ◽  
Interferon Response ◽  
Transcriptional Level ◽  
Type I ◽  
Type Ii ◽  
Wild Type ◽  
Guanylate Binding Protein

Lymphotoxinβreceptor (LTβR) signaling plays an important role in efficient initiation of host responses to a variety of pathogens, encompassing viruses, bacteria, and protozoans via induction of the type I interferon response. The present study reveals that afterToxoplasma gondiiinfection, LTβR−/−mice show a substantially reduced survival rate when compared to wild-type mice. LTβR−/−mice exhibit an increased parasite load and a more pronounced organ pathology. Also, a delayed increase of serum IL-12p40 and a failure of the protective IFNγresponse in LTβR−/−mice were observed. Serum NO levels in LTβR−/−animals rose later and were markedly decreased compared to wild-type animals. At the transcriptional level, LTβR−/−animals exhibited a deregulated expression profile of several cytokines known to play a role in activation of innate immunity inT. gondiiinfection. Importantly, expression of the IFNγ-regulated murine guanylate-binding protein (mGBP) genes was virtually absent in the lungs of LTβR−/−mice. This demonstrates clearly that the LTβR is essential for the induction of a type II IFN-mediated immune response againstT. gondii. The pronounced inability to effectively upregulate host defense effector molecules such as GBPs explains the high mortality rates of LTβR−/−animals afterT. gondiiinfection.

scholarly journals Aging-induced type I interferon response at the choroid plexus negatively affects brain function

Science ◽  
2014 ◽  
Vol 346 (6205) ◽  
pp. 89-93 ◽  
Author(s):  
Kuti Baruch ◽  
Aleksandra Deczkowska ◽  
Eyal David ◽  
Joseph M. Castellano ◽  
Omer Miller ◽  
...  
Keyword(s):  
Cognitive Decline ◽  
Choroid Plexus ◽  
Brain Function ◽  
Type I Interferon ◽  
Negative Influence ◽  
Hippocampal Neurogenesis ◽  
Interferon Response ◽  
Type I ◽  
Aged Mice ◽  
The Brain

Aging-associated cognitive decline is affected by factors produced inside and outside the brain. By using multiorgan genome-wide analysis of aged mice, we found that the choroid plexus, an interface between the brain and the circulation, shows a type I interferon (IFN-I)–dependent gene expression profile that was also found in aged human brains. In aged mice, this response was induced by brain-derived signals, present in the cerebrospinal fluid. Blocking IFN-I signaling within the aged brain partially restored cognitive function and hippocampal neurogenesis and reestablished IFN-II–dependent choroid plexus activity, which is lost in aging. Our data identify a chronic aging-induced IFN-I signature, often associated with antiviral response, at the brain’s choroid plexus and demonstrate its negative influence on brain function, thereby suggesting a target for ameliorating cognitive decline in aging.

scholarly journals Early Control of H5N1 Influenza Virus Replication by the Type I Interferon Response in Mice

2009 ◽  
Vol 83 (11) ◽  
pp. 5825-5834 ◽  
Author(s):  
Kristy J. Szretter ◽  
Shivaprakash Gangappa ◽  
Jessica A. Belser ◽  
Hui Zeng ◽  
Hualan Chen ◽  
...  
Keyword(s):  
H5n1 Virus ◽  
Type I Interferon ◽  
Influenza Viruses ◽  
Interferon Response ◽  
Type I ◽  
Wild Type ◽  
H5n1 Influenza ◽  
Deficient Mice

ABSTRACT Widespread distribution of highly pathogenic avian H5N1 influenza viruses in domesticated and wild birds continues to pose a threat to public health, as interspecies transmission of virus has resulted in increasing numbers of human disease cases. Although the pathogenic mechanism(s) of H5N1 influenza viruses has not been fully elucidated, it has been suggested that the ability to evade host innate responses, such as the type I interferon response, may contribute to the virulence of these viruses in mammals. We investigated the role that type I interferons (alpha/beta interferon [IFN-α/β]) might play in H5N1 pathogenicity in vivo, by comparing the kinetics and outcomes of H5N1 virus infection in IFN-α/β receptor (IFN-α/βR)-deficient and SvEv129 wild-type mice using two avian influenza A viruses isolated from humans, A/Hong Kong/483/97 (HK/483) and A/Hong Kong/486/97 (HK/486), which exhibit high and low lethality in mice, respectively. IFN-α/βR-deficient mice experienced significantly more weight loss and more rapid time to death than did wild-type mice. HK/486 virus caused a systemic infection similar to that with HK/483 virus in IFN-α/βR-deficient mice, suggesting a role for IFN-α/β in controlling the systemic spread of this H5N1 virus. HK/483 virus replicated more efficiently than HK/486 virus both in vivo and in vitro. However, replication of both viruses was significantly reduced following pretreatment with IFN-α/β. These results suggest a role for the IFN-α/β response in the control of H5N1 virus replication both in vivo and in vitro, and as such it may provide some degree of protection to the host in the early stages of infection.

scholarly journals Exploring zebrafish larvae as a COVID-19 model: probable SARS-COV-2 replication in the swim bladder

2021 ◽  
Author(s):  
Valerio Laghi ◽  
Veronica Rezelj ◽  
Laurent Boucontet ◽  
Pierre Boudinot ◽  
Irene Salinas ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Interferon Response ◽  
Type I ◽  
Swim Bladder ◽  
Wild Type ◽  
Zebrafish Larvae ◽  
Cytokine Responses ◽  
Successful Infection ◽  
Plasmid Injection ◽  
Brain Ventricle

Animal models are essential to understand COVID-19 pathophysiology and for pre-clinical assessment of drugs and other therapeutic or prophylactic interventions. We explored the small, cheap and transparent zebrafish larva as a potential host for the SARS-CoV-2 virus. Bath exposure, as well as microinjection in the coelom, pericardium, brain ventricle, bloodstream, or yolk, did not result in detectable SARS-CoV-2 replication in wild-type larvae. However, when the virus was inoculated in the swim bladder, a modest increase in viral RNA was observed after 24 hours, suggesting a successful infection in some animals. The low infectivity of SARS- CoV-2 in zebrafish was not due to the host type I interferon response, as similar results were observed in type I interferon-deficient animals. We could not detect the induction of transcriptional type I interferon or inflammatory cytokine responses following infection. Overexpression of human ACE2 in a mosaic fashion by plasmid injection in eggs was not sufficient to increase SARS-CoV-2 infectivity. In conclusion, wild-type zebrafish larvae appear mostly non-permissive to SARS-CoV-2, except in the swim bladder, an aerial organ sharing similarities with lungs.

scholarly journals Chronic exposure to Cytolethal Distending Toxin (CDT) promotes a cGAS-dependent type I interferon response

2021 ◽  
Author(s):  
Benoît J. Pons ◽  
Aurélie Pettes-Duler ◽  
Claire Naylies ◽  
Frédéric Taieb ◽  
Catherine Bouchenot ◽  
...  
Keyword(s):  
Immune Response ◽  
Dna Damage ◽  
Chronic Exposure ◽  
Pathogenic Bacteria ◽  
Type I Interferon ◽  
Natural Infection ◽  
Guanosine Monophosphate ◽  
Interferon Response ◽  
Type I ◽  
Cytolethal Distending Toxin

AbstractThe Cytolethal Distending Toxin (CDT) is a bacterial genotoxin produced by pathogenic bacteria causing major foodborne diseases worldwide. CDT activates the DNA Damage Response and modulates the host immune response, but the precise relationship between these outcomes has not been addressed so far. Here, we show that chronic exposure to CDT in HeLa cells or mouse embryonic fibroblasts promotes a strong type I interferon (IFN) response that depends on the cytoplasmic DNA sensor cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS) through the recognition of micronuclei. Indeed, despite active cell cycle checkpoints and in contrast to other DNA damaging agents, cells exposed to CDT reach mitosis where they accumulate massive DNA damage, resulting in chromosome fragmentation and micronucleus formation in daughter cells. These mitotic phenotypes are observed with CDT from various origins and in cancer or normal cell lines. Finally, we show that CDT exposure in immortalized normal colonic epithelial cells is associated to cGAS protein loss and low type I IFN response, implying that CDT immunomodulatory function may vary depending on tissue and cell type. Thus, our results establish a direct link between CDT-induced DNA damage, genetic instability and the cellular immune response that may be relevant in the context of natural infection associated to chronic inflammation or carcinogenesis.

Viral Invasion and Type I Interferon Response Characterize the Immunophenotypes during COVID-19 Infection

2020 ◽  
Author(s):  
Lai Wei ◽  
Siqi Ming ◽  
Bin Zou ◽  
Yongjian Wu ◽  
Zhongsi Hong ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Interferon Response ◽  
Type I
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