Endomembrane targeting of human OAS1 p46 augments antiviral activity.
Ontology highlight
ABSTRACT:
SUBMITTER: Soveg FW
PROVIDER: S-EPMC8357416 | biostudies-literature | 2021 Aug
REPOSITORIES: biostudies-literature
Publications
Endomembrane targeting of human OAS1 p46 augments antiviral activity.
Soveg Frank W FW Schwerk Johannes J Gokhale Nandan S NS Cerosaletti Karen K Smith Julian R JR Pairo-Castineira Erola E Kell Alison M AM Forero Adriana A Zaver Shivam A SA Esser-Nobis Katharina K Roby Justin A JA Hsiang Tien-Ying TY Ozarkar Snehal S Clingan Jonathan M JM McAnarney Eileen T ET Stone Amy El AE Malhotra Uma U Speake Cate C Perez Joseph J Balu Chiraag C Allenspach Eric J EJ Hyde Jennifer L JL Menachery Vineet D VD Sarkar Saumendra N SN Woodward Joshua J JJ Stetson Daniel B DB Baillie John Kenneth JK Buckner Jane H JH Gale Michael M Savan Ram R
eLife 20210803
Many host RNA sensors are positioned in the cytosol to detect viral RNA during infection. However, most positive-strand RNA viruses replicate within a modified organelle co-opted from intracellular membranes of the endomembrane system, which shields viral products from cellular innate immune sensors. Targeting innate RNA sensors to the endomembrane system may enhance their ability to sense RNA generated by viruses that use these compartments for replication. Here, we reveal that an isoform of ol ...[more]
Similar Datasets
Project description:BackgroundThe expression of 2'-5'-Oligoadenylate synthetases (OASs) is induced by type 1 Interferons (IFNs) in response to viral infection. The OAS proteins have a unique ability to produce 2'-5' Oligoadenylates, which bind and activate the ribonuclease RNase L. The RNase L degrades cellular RNAs which in turn inhibits protein translation and induces apoptosis. Several single nucleotide polymorphisms (SNPs) in the OAS1 gene have been associated with disease. We have investigated the functional effect of two common SNPs in the OAS1 gene. The SNP rs10774671 affects splicing to one of the exons in the OAS1 gene giving rise to differential expression of the OAS1 isoforms, and the SNP rs1131454 (former rs3741981) resides in exon 3 giving rise to OAS1 isoforms with either a Glycine or a Serine at position 162 in the core OAS unit.ResultsWe have used three human cell lines with different genotypes in the OAS1 SNP rs10774671, HeLa cells with the AA genotype, HT1080 cells with AG, and Daudi cells with GG. The main OAS1 isoform expressed in Daudi and HT1080 cells was p46, and the main OAS1 isoform expressed in HeLa cells was p42. In addition, low levels of the OAS1 p52 mRNA was detected in HeLa cells and p48 mRNA in Daudi cells, and trace amounts of p44a mRNA were detected in the three cell lines treated with type 1 interferon. We show that the OAS1 p46 isoform was localized in the mitochondria in Daudi cells, whereas the OAS1 isoforms in HeLa cells were primarily localized in cytoplasmic vacuoles/lysosomes. By using recombinantly expressed OAS1 mutant proteins, we found that the OAS1 SNP rs1131454 (former rs3741981) did not affect the enzymatic OAS1 activity.ConclusionsThe SNP rs10774671 determines differential expression of the OAS1 isoforms. In Daudi and HT1080 cells the p46 isoform is the most abundantly expressed isoform associated with the G allele, whereas in HeLa cells the most abundantly expressed isoform is p42 associated with the A allele. The SNP rs1131454 (former rs3741981) does not interfere with OAS1 enzyme activity. The OAS1 p46 isoform localizes to the mitochondria, therefore a full 2-5A system can now be found in the mitochondria.
| S-EPMC4165621 | biostudies-literature
Project description:Immune responses counteract infections but also cause collateral damage to hosts. Oligoadenylate synthetase 1 (OAS1) binds double-stranded RNA from invading viruses and produces 2'-5' linked oligoadenylate (2-5A) to activate ribonuclease L (RNase L), which cleaves RNA to inhibit virus replication. OAS1 can also undergo autoactivation by host RNAs, a potential trade-off to antiviral activity. We investigated functional variation in primate OAS1 as a model for how immune pathways evolve to mitigate costs and observed a surprising frequency of loss-of-function variation. In gorillas, we identified a polymorphism that severely decreases catalytic function, mirroring a common variant in humans that impairs 2-5A synthesis through alternative splicing. OAS1 loss-of-function variation is also common in monkeys, including complete loss of 2-5A synthesis in tamarins. The frequency of loss-of-function alleles suggests that costs associated with OAS1 activation can be so detrimental to host fitness that pathogen-protective effects are repeatedly forfeited.
| S-EPMC6609161 | biostudies-literature
Project description:APOBEC3G (A3G) is a cytidine deaminase that restricts HIV-1 replication by inducing G-to-A hypermutation in viral DNA; deamination-independent mechanisms are also implicated. HIV-1 Vif protein counteracts A3G by inducing its proteasomal degradation. Thus, the Vif-A3G axis is a potential therapeutic target. To identify compounds that inhibit Vif:A3G interaction, a 307,520 compound library was tested in a TR-FRET screen. Two identified compounds, redoxal and lomofungin, inhibited HIV-1 replication in peripheral blood mononuclear cells. Lomofungin activity was linked to A3G, but not pursued further due to cytotoxicity. Redoxal displayed A3G-dependent restriction, inhibiting viral replication by stabilizing A3G protein levels and increasing A3G in virions. A3G-independent activity was also detected. Treatment with uridine or orotate, intermediates of pyrimidine synthesis, diminished redoxal-induced stabilization of A3G and antiviral activity. These results identify redoxal as an inhibitor of HIV-1 replication and suggest its ability to inhibit pyrimidine biosynthesis suppresses viral replication by augmenting A3G antiviral activity.
| S-EPMC4567410 | biostudies-literature
Project description:The human OAS1 (hOAS1) gene produces multiple possible isoforms due to alternative splicing events and sequence variation among individuals, some of which affect splicing. The unique C-terminal sequences of the hOAS1 isoforms could differentially affect synthetase activity, protein stability, protein partner interactions and/or cellular localization. Recombinant p41, p42, p44, p46, p48, p49 and p52 hOAS1 isoform proteins expressed in bacteria were each able to synthesize trimer and higher order 2'-5' linked oligoadenylates in vitro in response to poly(I:C). The p42, p44, p46, p48 and p52 isoform proteins were each able to induce RNase-mediated rRNA cleavage in response to poly(I:C) when overexpressed in HEK293 cells. The expressed levels of the p42 and p46 isoform proteins were higher than those of the other isoforms, suggesting increased stability in mammalian cells. In a yeast two-hybrid screen, Fibrillin1 (FBN1) was identified as a binding partner for hOAS1 p42 isoform, and Supervillin (SVIL) as a binding partner for the p44 isoform. The p44-SVIL interaction was supported by co-immunoprecipitation data from mammalian cells. The data suggest that the unique C-terminal regions of hOAS1 isoforms may mediate the recruitment of different partners, alternative functional capacities and/or different cellular localization.
| S-EPMC7077331 | biostudies-literature
Project description:Oligoadenylate synthetases (OAS) are interferon-induced enzymes that participate in the first line of defense against a wide range of viral infection in animals. Upon activation by viral double-stranded RNA, OAS synthesizes (2-5) oligoadenylates, which activate RNase L, leading to the nonspecific degradation of cellular and viral RNA. Some association studies in humans suggest that variation at one of the OAS genes, OAS1, could be influencing host susceptibility to viral infection. We assessed the diversity of OAS1 in hominoid primates with a focus on chimpanzees. We found that the OAS1 gene is extremely polymorphic in Central African chimpanzee and exhibits levels of silent and replacement diversity much higher than neutral regions of the chimpanzee genome. This level of variation strongly suggests that balancing selection is acting on OAS1, and indeed, this conclusion was validated by several tests of neutrality. We further demonstrated that balancing selection has been acting at this locus since the split between chimpanzees, humans, and gorillas (~8.6 Ma) and caused the persistence of two deeply divergent allelic lineages in Central African chimpanzees. These two groups of OAS1 alleles differ by a large number of amino acids (a.a.), including several a.a. putatively involved in RNA binding. It is therefore very likely that variation at the OAS1 locus affects the innate immune response of individuals to specific viral infection. Our data strongly suggest that interactions between viral RNA and OAS1 are responsible for the maintenance of ancestral polymorphisms at this locus for at least 13.2 My.
| S-EPMC3341824 | biostudies-literature
Project description:Human cytomegalovirus (HCMV) is an important pathogen for which new antiviral drugs are needed. HCMV, like other herpesviruses, encodes a nuclear egress complex (NEC) composed of two subunits, UL50 and UL53, whose interaction is crucial for viral replication. To explore whether small molecules can exert selective antiviral activity by inhibiting NEC subunit interactions, we established a homogeneous time-resolved fluorescence (HTRF) assay of these interactions and used it to screen >200,000 compound-containing wells. Two compounds, designated GK1 and GK2, which selectively inhibited this interaction in the HTRF assay with GK1 also active in a co-immunoprecipitation assay, exhibited more potent anti-HCMV activity than cytotoxicity or activity against another herpesvirus. At doses that substantially reduced HCMV plaque formation, GK1 and GK2 had little or no effect on the expression of viral proteins and reduced the co-localization of UL53 with UL50 at the nuclear rim in a subset of cells. GK1 and GK2 contain an acrylamide moiety predicted to covalently interact with cysteines, and an analog without this potential lacked activity. Mass spectrometric analysis showed binding of GK2 to multiple cysteines on UL50 and UL53. Nevertheless, substitution of cysteine 214 of UL53 with serine (C214S) ablated detectable inhibitory activity of GK1 and GK2 in vitro, and the C214S substitution engineered into HCMV conferred resistance to GK1, the more potent of the two inhibitors. Thus, GK1 exerts selective antiviral activity by targeting the NEC. Docking studies suggest that the acrylamide tethers one end of GK1 or GK2 to C214 within a pocket of UL53, permitting the other end of the molecule to sterically hinder UL50 to prevent NEC formation. Our results prove the concept that targeting the NEC with small molecules can selectively block HCMV replication. Such compounds could serve as a foundation for development of anti-HCMV drugs and as chemical tools for studying HCMV.
| S-EPMC10691697 | biostudies-literature
Project description:The development of durable new antiviral therapies is challenging, as viruses can evolve rapidly to establish resistance and attenuate therapeutic efficacy. New compounds that selectively target conserved viral features are attractive therapeutic candidates, particularly for combating newly emergent viral threats. The innate immune system features a sustained capability to combat pathogens through production of antimicrobial peptides (AMPs); however, these AMPs have shortcomings that can preclude clinical use. The essential functional features of AMPs have been recapitulated by peptidomimetic oligomers, yielding effective antibacterial and antifungal agents. Here, we show that a family of AMP mimetics, called peptoids, exhibit direct antiviral activity against an array of enveloped viruses, including the key human pathogens Zika, Rift Valley fever, and chikungunya viruses. These data suggest that the activities of peptoids include engagement and disruption of viral membrane constituents. To investigate how these peptoids target lipid membranes, we used liposome leakage assays to measure membrane disruption. We found that liposomes containing phosphatidylserine (PS) were markedly sensitive to peptoid treatment; in contrast, liposomes formed exclusively with phosphatidylcholine (PC) showed no sensitivity. In addition, chikungunya virus containing elevated envelope PS was more susceptible to peptoid-mediated inactivation. These results indicate that peptoids mimicking the physicochemical characteristics of AMPs act through a membrane-specific mechanism, most likely through preferential interactions with PS. We provide the first evidence for the engagement of distinct viral envelope lipid constituents, establishing an avenue for specificity that may enable the development of a new family of therapeutics capable of averting the rapid development of resistance.
| S-EPMC10425984 | biostudies-literature
Project description:Human papillomavirus (HPV) infections are a major human health problem; they are the cause of recurrent benign warts and of several cancers of the anogenital tract and head and neck region. Although there are two prophylactic HPV vaccines that could, if used universally, prevent as many as two-thirds of HPV-induced cancers, as well as several cytotoxic and immunomodulatory agents for localized treatment of infections, there are currently no HPV antiviral drugs in our arsenal of therapeutic agents. This review examines the status of past and ongoing research into the development of HPV antivirals, focused primarily upon approaches targeting the replication of the viral genome. The only HPV enzyme, E1, is a DNA helicase that interfaces with the cellular DNA replication machinery to replicate the HPV genome. To date, searches for small molecule inhibitors of E1 for use as antivirals have met with limited success. The lack of other viral enzymes has meant that the search for antivirals has shifted to a large degree to the modulation of protein-protein interactions. There has been some success in identifying small molecule inhibitors targeting interactions between HPV proteins but with activity against a small subset of viral types only. As noted in this review, it is thought that targeting E1 interactions with cellular replication proteins may provide inhibitors with broader activity against multiple HPV types. Herein, we outline the steps in HPV DNA replication and discuss those that appear to provide the most advantageous targets for the development of anti-HPV therapeutics.
| S-EPMC4658057 | biostudies-other
Project description:The oligoadenylate synthetase 1 (OAS1) enzyme acts as an innate sensor of viral infection and plays a major role in the defense against a wide diversity of viruses. Polymorphisms at OAS1 have been shown to correlate with differential susceptibility to several infections of great public health significance, including hepatitis C virus, SARS coronavirus, and West Nile virus. Population genetics analyses in hominoids have revealed interesting evolutionary patterns. In Central African chimpanzee, OAS1 has evolved under long-term balancing selection, resulting in the persistence of polymorphisms since the origin of hominoids, whereas human populations have acquired and retained OAS1 alleles from Neanderthal and Denisovan origin. We decided to further investigate the evolution of OAS1 in primates by characterizing intra-specific variation in four species commonly used as models in infectious disease research: the rhesus macaque, the cynomolgus macaque, the olive baboon, and the Guinea baboon. In baboons, OAS1 harbors a very low level of variation. In contrast, OAS1 in macaques exhibits a level of polymorphism far greater than the genomic average, which is consistent with the action of balancing selection. The region of the enzyme that directly interacts with viral RNA, the RNA-binding domain, contains a number of polymorphisms likely to affect the RNA-binding affinity of OAS1. This strongly suggests that pathogen-driven balancing selection acting on the RNA-binding domain of OAS1 is maintaining variation at this locus. Interestingly, we found that a number of polymorphisms involved in RNA-binding were shared between macaques and chimpanzees. This represents an unusual case of convergent polymorphism.
| S-EPMC4809017 | biostudies-literature
Project description:Enteroviruses belong to the genus Enterovirus of the family Picornaviridae and include four human enterovirus groups (EV-A to -D): the epidemic of enteroviruses such as human enterovirus A71 (EV-A71) and coxsackievirus A16 (CVA16) is a threat to global public health. Enteroviral protein 2C is the most conserved nonstructural protein among all enteroviruses and possesses RNA helicase activity that plays pivotal roles during enteroviral life cycles, which makes 2C an attractive target for developing antienterovirus drugs. In this study, we designed a peptide, named 2CL, based on the structure of EV-A71 2C. This peptide effectively impaired the oligomerization of EV-A71 2C protein and inhibited the RNA helicase activities of 2C proteins encoded by EV-A71 and CVA16, both of which belong to EV-A, and showed potent antiviral efficacy against EV-A71 and CVA16 in cells. Moreover, the 2CL treatment elicited a strong in vivo protective efficacy against lethal EV-A71 challenge. In addition, the antiviral strategy of targeting the 2C helicase activity can be applied to inhibit the replication of EV-B. Either 2CL or B-2CL, the peptide redesigned based on the 2CL-corresponding sequence of EV-Bs, could exert effective antiviral activity against two important EV-Bs, coxsackievirus B3 and echovirus 11. Together, our findings demonstrated that targeting the helicase activity of 2C with a rationally designed peptide is an efficient antiviral strategy against enteroviruses, and 2CL and B-2CL show promising clinical potential to be further developed as broad-spectrum antienterovirus drugs.IMPORTANCE Enteroviruses are a large group of positive-sense single-stranded RNA viruses and include numerous human pathogens, such as enterovirus A71 (EV-A71), coxsackieviruses, and echoviruses. However, no approved EV antiviral drugs are available. Enteroviral 2C is the most conserved nonstructural protein among all enteroviruses and contains the RNA helicase activity critical for the viral life cycle. Herein, according to the structure of EV-A71 2C, we designed a peptide that effectively inhibited the RNA helicase activities of EV-A71- and coxsackievirus A16 (CVA16)-encoded 2C proteins. Moreover, this peptide exerted potent antiviral effects against EV-A71 and CVA16 in cells and elicited therapeutic efficacy against lethal EV-A71 challenge in vivo Furthermore, we demonstrate that the strategy of targeting the 2C helicase activity can be used for other relevant enteroviruses, including coxsackievirus B3 and echovirus 11. In summary, our findings provide compelling evidence that the designed peptides targeting the helicase activity of 2C could be broad-spectrum antivirals for enteroviruses.
| S-EPMC8315976 | biostudies-literature