The IFITMs Inhibit Zika Virus Replication Savidis, George; Perreira, Jill M.; Portmann, Jocelyn M. ...
Cell reports (Cambridge),
06/2016, Letnik:
15, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Zika virus has emerged as a severe health threat with a rapidly expanding range. The IFITM family of restriction factors inhibits the replication of a broad range of viruses, including the closely ...related flaviruses West Nile virus and dengue virus. Here, we show that IFITM1 and IFITM3 inhibit Zika virus infection early in the viral life cycle. Moreover, IFITM3 can prevent Zika-virus-induced cell death. These results suggest that strategies to boost the actions and/or levels of the IFITMs might be useful for inhibiting a broad range of emerging viruses.
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•IFITM3 and IFITM1 inhibit Zika virus infection•IFITM3 can prevent Zika-virus-induced cell death•The IFITMs can halt Zika virus early in the viral life cycle
Savidis et al. find that the IFITMs block Zika virus replication, including that of a recently isolated strain from Cambodia. Importantly, this protection translates into a large reduction in Zika-virus-induced cell death. The authors develop an imaging assay and determine that IFITM3 blocks the very earliest stages of Zika virus infection.
The flaviviruses dengue virus (DENV) and Zika virus (ZIKV) are severe health threats with rapidly expanding ranges. To identify the host cell dependencies of DENV and ZIKV, we completed orthologous ...functional genomic screens using RNAi and CRISPR/Cas9 approaches. The screens recovered the ZIKV entry factor AXL as well as multiple host factors involved in endocytosis (RAB5C and RABGEF), heparin sulfation (NDST1 and EXT1), and transmembrane protein processing and maturation, including the endoplasmic reticulum membrane complex (EMC). We find that both flaviviruses require the EMC for their early stages of infection. Together, these studies generate a high-confidence, systems-wide view of human-flavivirus interactions and provide insights into the role of the EMC in flavivirus replication.
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•RNAi and CRISPR/Cas9 screens were used to find flavivirus dependencies•The screens recovered host factors involved in endocytosis and heparin sulfation•The EMC is required by DENV and ZIKV in the early stages of replication•These studies give a systems-wide view of human-flavivirus interactions
Savidis et al. identify DENV and ZIKV dependencies using orthologous RNAi and CRISPR/Cas9 approaches. Multiple host factors involved in endocytosis and transmembrane protein processing, including the endoplasmic reticulum membrane complex (EMC), are important for flaviviral replication. Together, their studies generate a systems-wide view of human-flavivirus interactions.
The interferon-inducible transmembrane protein (IFITM) family inhibits a growing number of pathogenic viruses, among them influenza A virus, dengue virus, hepatitis C virus, and Ebola virus. This ...review covers recent developments in our understanding of the IFITM's molecular determinants, potential mechanisms of action, and impact on pathogenesis.
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•IFITMs are host intramembrane proteins that block viral fusion resulting in virus degradation.•IFITMs inhibit a growing number of pathogenic viruses, including influenza A virus, dengue virus, and Ebola virus.•Mice null for Ifitm3 exhibit increased disease severity when infected with the influenza A virus.•Patients expressing a variant allele of IFITM3 are more likely to develop severe influenza infection.•Recent work suggests that IFITMs may toughen the host membrane, thus preventing viral membrane fusion.
Direct visualization of HIV-1 replication would improve our understanding of the viral life cycle. We adapted established technology and reagents to develop an imaging approach, ViewHIV, which ...allows evaluation of early HIV-1 replication intermediates, from reverse transcription to integration. These methods permit the simultaneous evaluation of both the capsid protein (CA) and viral DNA genome (vDNA) components of HIV-1 in both the cytosol and nuclei of single cells. ViewHIV is relatively rapid, uses readily available reagents in combination with standard confocal microscopy, and can be done with virtually any HIV-1 strain and permissive cell lines or primary cells. Using ViewHIV, we find that CA enters the nucleus and associates with vDNA in both transformed and primary cells. We also find that CA’s interaction with the host polyadenylation factor, CPSF6, enhances nuclear entry and potentiates HIV-1’s depth of nuclear invasion, potentially aiding the virus’s integration into gene-dense regions.
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•ViewHIV visualizes the HIV-1 capsid and viral DNA in the cytosol and nucleus•ViewHIV can be done with any HIV-1 strain and primary cells•ViewHIV shows that CA enters the nucleus and associates with vDNA•CA’s interaction with CPSF6 promotes HIV-1’s nuclear entry and integration
Chin et al. have developed an imaging assay, ViewHIV, which evaluates early HIV-1 replication intermediates. ViewHIV uses available reagents and works with primary cells. Using ViewHIV, they find that CA enters the nucleus and associates with vDNA. Furthermore, CA’s interaction with the host factor CPSF6 modulates HIV-1’s nuclear entry and integration.
A human cytomegalovirus (HCMV) pentameric glycoprotein complex (PC), gH–gL–UL128–UL130–UL131A, is necessary for viral infection of clinically relevant cell types, including epithelial cells, which ...are important for interhost transmission and disease. We performed genome-wide CRISPR/Cas9 screens of different cell types in parallel to identify host genes specifically required for HCMV infection of epithelial cells. This effort identified a multipass membrane protein, OR14I1, as a receptor for HCMV infection. This olfactory receptor family member is required for HCMV attachment, entry, and infection of epithelial cells and is dependent on the presence of viral PC. OR14I1 is required for AKT activation and mediates endocytosis entry of HCMV. We further found that HCMV infection of epithelial cells is blocked by a synthetic OR14I1 peptide and inhibitors of adenylate cyclase and protein kinase A (PKA) signaling. Identification of OR14I1 as a PC-dependent HCMV host receptor associated with epithelial tropism and the role of the adenylate cyclase/PKA/AKT–mediated signaling pathway in HCMV infection reveal previously unappreciated targets for the development of vaccines and antiviral therapies.
The IFITMs inhibit influenza A virus (IAV) replication in vitro and in vivo. Here, we establish that the antimycotic heptaen, amphotericin B (AmphoB), prevents IFITM3-mediated restriction of IAV, ...thereby increasing viral replication. Consistent with its neutralization of IFITM3, a clinical preparation of AmphoB, AmBisome, reduces the majority of interferon’s protective effect against IAV in vitro. Mechanistic studies reveal that IFITM1 decreases host-membrane fluidity, suggesting both a possible mechanism for IFITM-mediated restriction and its negation by AmphoB. Notably, we reveal that mice treated with AmBisome succumbed to a normally mild IAV infection, similar to animals deficient in Ifitm3. Therefore, patients receiving antifungal therapy with clinical preparations of AmphoB may be functionally immunocompromised and thus more vulnerable to influenza, as well as other IFITM3-restricted viral infections.
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•Amphotericin B or AmBisome prevents IFITM3-mediated restriction of IAV•AmBisome overcomes the majority of IFN’s antiviral effects in vitro•IFITM1 decreases membrane fluidity and inhibits membrane fusion•AmBisome increases the morbidity and mortality of influenza
IFITM3 is a ubiquitously expressed antiviral protein that inhibits multiple human pathogenic viruses, including influenza A virus (IAV). Brass and colleagues now show that a widely used antifungal therapy, AmBisome, prevents IFITM3 from blocking IAV replication and that mice given AmBisome succumb to a normally mild influenza virus infection. Therefore, patients receiving antifungal therapy with AmBisome may be functionally immunocompromised and thus more vulnerable to influenza as well as other IFITM3-restricted viral infections.
HIV-1 integration into the host genome favors actively transcribed genes. Prior work indicated that the nuclear periphery provides the architectural basis for integration site selection, with viral ...capsid-binding host cofactor CPSF6 and viral integrase-binding cofactor LEDGF/p75 contributing to selection of individual sites. Here, by investigating the early phase of infection, we determine that HIV-1 traffics throughout the nucleus for integration. CPSF6-capsid interactions allow the virus to bypass peripheral heterochromatin and penetrate the nuclear structure for integration. Loss of interaction with CPSF6 dramatically alters virus localization toward the nuclear periphery and integration into transcriptionally repressed lamina-associated heterochromatin, while loss of LEDGF/p75 does not significantly affect intranuclear HIV-1 localization. Thus, CPSF6 serves as a master regulator of HIV-1 intranuclear localization by trafficking viral preintegration complexes away from heterochromatin at the periphery toward gene-dense chromosomal regions within the nuclear interior.
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•CA-CPSF6 interaction as opposed to nuclear periphery dictates HIV-1 integration•CPSF6 enables HIV-1 to penetrate the nuclear interior beyond the nuclear periphery•Loss of CPSF6 interaction results in integration at lamina-associated domains•LEDGF/p75 does not play a significant role in intranuclear HIV-1 localization
Prior work indicated that the nuclear periphery dictated HIV-1 integration site selection. Using multiple orthologous approaches, Achuthan et al. fail to garner evidence for preferential targeting of the periphery. The interaction between viral capsid and CPSF6 enables HIV-1 to bypass integration into peripheral heterochromatin and penetrate the nuclear structure for integration.
Human rhinovirus (HRV) causes upper respiratory infections and asthma exacerbations. We screened multiple orthologous RNAi reagents and identified host proteins that modulate HRV replication. Here, ...we show that RNASEK, a transmembrane protein, was needed for the replication of HRV, influenza A virus, and dengue virus. RNASEK localizes to the cell surface and endosomal pathway and closely associates with the vacuolar ATPase (V-ATPase) proton pump. RNASEK is required for endocytosis, and its depletion produces enlarged clathrin-coated pits (CCPs) at the cell surface. These enlarged CCPs contain endocytic cargo and are bound by the scissioning GTPase, DNM2. Loss of RNASEK alters the localization of multiple V-ATPase subunits and lowers the levels of the ATP6AP1 subunit. Together, our results show that RNASEK closely associates with the V-ATPase and is required for its function; its loss prevents the early events of endocytosis and the replication of multiple pathogenic viruses.
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•Host proteins that modulate HRV replication were found by using MORR screens•RNASEK is needed for the replication of HRV, influenza A virus, and dengue virus•RNASEK localizes to the cell surface and endosomal pathway along with the V-ATPase•RNASEK is needed for endocytosis, and its loss produces enlarged clathrin-coated pits
Perreira et al. screened multiple orthologous RNAi reagents and identified host proteins that modulate human rhinovirus (HRV) replication. They found that RNASEK is needed for the replication of HRV, influenza A virus, and dengue virus, associates with the vacuolar ATPase (V-ATPase), and is required for endocytosis.
People living with HIV (PLWH) have expressed concern about the life-long burden and stigma associated with taking pills daily and can experience medication fatigue that might lead to suboptimal ...treatment adherence and the emergence of drug-resistant viral variants, thereby limiting future treatment options
. As such, there is strong interest in long-acting antiretroviral (ARV) agents that can be administered less frequently
. Herein, we report GS-CA1, a new archetypal small-molecule HIV capsid inhibitor with exceptional potency against HIV-2 and all major HIV-1 types, including viral variants resistant to the ARVs currently in clinical use. Mechanism-of-action studies indicate that GS-CA1 binds directly to the HIV-1 capsid and interferes with capsid-mediated nuclear import of viral DNA, HIV particle production and ordered capsid assembly. GS-CA1 selects in vitro for unfit GS-CA1-resistant capsid variants that remain fully susceptible to other classes of ARVs. Its high metabolic stability and low solubility enabled sustained drug release in mice following a single subcutaneous dosing. GS-CA1 showed high antiviral efficacy as a long-acting injectable monotherapy in a humanized mouse model of HIV-1 infection, outperforming long-acting rilpivirine. Collectively, these results demonstrate the potential of ultrapotent capsid inhibitors as new long-acting agents for the treatment of HIV-1 infection.
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