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Wang J, Luo Y, Katiyar H, Liang C, Liu Q. The Antiviral Activity of Interferon-Induced Transmembrane Proteins and Virus Evasion Strategies. Viruses 2024; 16:734. [PMID: 38793616 PMCID: PMC11125860 DOI: 10.3390/v16050734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/01/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024] Open
Abstract
Interferons (IFNs) are antiviral cytokines that defend against viral infections by inducing the expression of interferon-stimulated genes (ISGs). Interferon-inducible transmembrane proteins (IFITMs) 1, 2, and 3 are crucial ISG products and members of the CD225 protein family. Compelling evidence shows that IFITMs restrict the infection of many unrelated viruses by inhibiting the virus-cell membrane fusion at the virus entry step via the modulation of lipid composition and membrane properties. Meanwhile, viruses can evade IFITMs' restrictions by either directly interacting with IFITMs via viral glycoproteins or by altering the native entry pathway. At the same time, cumulative evidence suggests context-dependent and multifaceted roles of IFITMs in modulating virus infections and cell signaling. Here, we review the diverse antiviral mechanisms of IFITMs, the viral antagonizing strategies, and the regulation of IFITM activity in host cells. The mechanisms behind the antiviral activity of IFITMs could aid the development of broad-spectrum antivirals and enhance preparedness for future pandemics.
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Affiliation(s)
- Jingjing Wang
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, QC H9X 3V9, Canada; (J.W.); (Y.L.)
| | - Yuhang Luo
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, QC H9X 3V9, Canada; (J.W.); (Y.L.)
| | - Harshita Katiyar
- McGill Center for Viral Diseases, Lady Davis Institute, Montreal, QC H3T 1E2, Canada; (H.K.); (C.L.)
- Division of Experimental Medicine, McGill University, Montreal, QC H4A 3J1, Canada
| | - Chen Liang
- McGill Center for Viral Diseases, Lady Davis Institute, Montreal, QC H3T 1E2, Canada; (H.K.); (C.L.)
- Division of Experimental Medicine, McGill University, Montreal, QC H4A 3J1, Canada
| | - Qian Liu
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, QC H9X 3V9, Canada; (J.W.); (Y.L.)
- McGill Center for Viral Diseases, Lady Davis Institute, Montreal, QC H3T 1E2, Canada; (H.K.); (C.L.)
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Marshall LJ, Bailey J, Cassotta M, Herrmann K, Pistollato F. Poor Translatability of Biomedical Research Using Animals - A Narrative Review. Altern Lab Anim 2023; 51:102-135. [PMID: 36883244 DOI: 10.1177/02611929231157756] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
The failure rate for the translation of drugs from animal testing to human treatments remains at over 92%, where it has been for the past few decades. The majority of these failures are due to unexpected toxicity - that is, safety issues revealed in human trials that were not apparent in animal tests - or lack of efficacy. However, the use of more innovative tools, such as organs-on-chips, in the preclinical pipeline for drug testing, has revealed that these tools are more able to predict unexpected safety events prior to clinical trials and so can be used for this, as well as for efficacy testing. Here, we review several disease areas, and consider how the use of animal models has failed to offer effective new treatments. We also make some suggestions as to how the more human-relevant new approach methodologies might be applied to address this.
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Affiliation(s)
- Lindsay J Marshall
- Animal Research Issues, 94219The Humane Society of the United States, Gaithersburg, MD, USA
| | - Jarrod Bailey
- 380235Cruelty Free International, London, UK; 542332Animal Free Research UK, London, UK
| | | | - Kathrin Herrmann
- Johns Hopkins Bloomberg School of Public Health, 457389Center for Alternatives to Animal Testing, Baltimore, MD, USA; Senate Department for the Environment, Urban Mobility, Consumer Protection and Climate Action, Berlin, Germany
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3
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IFITM proteins: Understanding their diverse roles in viral infection, cancer, and immunity. J Biol Chem 2022; 299:102741. [PMID: 36435199 PMCID: PMC9800550 DOI: 10.1016/j.jbc.2022.102741] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/27/2022] [Accepted: 11/15/2022] [Indexed: 11/24/2022] Open
Abstract
Interferon-induced transmembrane proteins (IFITMs) are broad spectrum antiviral factors that inhibit the entry of a wide range of clinically important pathogens including influenza A virus, HIV-1, and Dengue virus. IFITMs are thought to act primarily by antagonizing virus-cell membrane fusion in this regard. However, recent work on these proteins has uncovered novel post-entry viral restriction mechanisms. IFITMs are also increasingly thought to have a role regulating immune responses, including innate antiviral and inflammatory responses as well as adaptive T-cell and B-cell responses. Further, IFITMs may have pathological activities in cancer, wherein IFITM expression can be a marker of therapeutically resistant and aggressive disease courses. In this review, we summarize the respective literatures concerning these apparently diverse functions with a view to identifying common themes and potentially yielding a more unified understanding of IFITM biology.
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Conformation of HIV-1 Envelope Governs Rhesus CD4 Usage and Simian-Human Immunodeficiency Virus Replication. mBio 2022; 13:e0275221. [PMID: 35012342 PMCID: PMC8749432 DOI: 10.1128/mbio.02752-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Infection of rhesus macaques with simian-human immunodeficiency viruses (SHIVs) is the preferred model system for vaccine development because SHIVs encode human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins (Envs)-a key target of HIV-1 neutralizing antibodies. Since the goal of vaccines is to prevent new infections, SHIVs encoding circulating HIV-1 Env are desired as challenge viruses. Development of such biologically relevant SHIVs has been challenging, as they fail to infect rhesus macaques, mainly because most circulating HIV-1 Envs do not use rhesus CD4 (rhCD4) receptor for viral entry. Most primary HIV-1 Envs exist in a closed conformation and occasionally transit to a downstream, open conformation through an obligate intermediate conformation. Here, we provide genetic evidence that open Env conformations can overcome the rhCD4 entry barrier and increase replication of SHIVs in rhesus lymphocytes. Consistent with prior studies, we found that circulating HIV-1 Envs do not use rhCD4 efficiently for viral entry. However, by using HIV-1 Envs with single amino acid substitutions that alter their conformational state, we found that transitions to intermediate and open Env conformations allow usage of physiological levels of rhCD4 for viral entry. We engineered these single amino acid substitutions in the transmitted/founder HIV-1BG505 Envs encoded by SHIV-BG505 and found that open Env conformation enhances SHIV replication in rhesus lymphocytes. Lastly, CD4-mediated SHIV pulldown, sensitivity to soluble CD4, and fusogenicity assays indicated that open Env conformation promotes efficient rhCD4 binding and viral-host membrane fusion. These findings identify the conformational state of HIV-1 Env as a major determinant for rhCD4 usage, viral fusion, and SHIV replication. IMPORTANCE Rhesus macaques are a critical animal model for preclinical testing of HIV-1 vaccine and prevention approaches. However, HIV-1 does not replicate in rhesus macaques, and thus, chimeric simian-human immunodeficiency viruses (SHIVs), which encode HIV-1 envelope glycoproteins (Envs), are used as surrogate challenge viruses to infect rhesus macaques for modeling HIV-1 infection. Development of SHIVs encoding Envs from clinically relevant, circulating HIV-1 variants has been extremely challenging, as such SHIVs replicate poorly, if at all, in rhesus lymphocytes. This is most probably because many circulating HIV-1 Envs do not use rhesus CD4 efficiently for viral entry. In this study, we identified conformational state of HIV-1 envelope as a key determinant for rhesus CD4 usage, viral-host membrane fusion, and SHIV replication in rhesus lymphocytes.
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Brezgin S, Kostyusheva A, Bayurova E, Volchkova E, Gegechkori V, Gordeychuk I, Glebe D, Kostyushev D, Chulanov V. Immunity and Viral Infections: Modulating Antiviral Response via CRISPR-Cas Systems. Viruses 2021; 13:1373. [PMID: 34372578 PMCID: PMC8310348 DOI: 10.3390/v13071373] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 12/13/2022] Open
Abstract
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.
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Affiliation(s)
- Sergey Brezgin
- National Medical Research Center of Tuberculosis and Infectious Diseases, Ministry of Health, 127994 Moscow, Russia; (S.B.); (A.K.); (V.C.)
- Institute of Immunology, Federal Medical Biological Agency, 115522 Moscow, Russia
- Scientific Center for Genetics and Life Sciences, Division of Biotechnology, Sirius University of Science and Technology, 354340 Sochi, Russia
| | - Anastasiya Kostyusheva
- National Medical Research Center of Tuberculosis and Infectious Diseases, Ministry of Health, 127994 Moscow, Russia; (S.B.); (A.K.); (V.C.)
| | - Ekaterina Bayurova
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, 108819 Moscow, Russia; (E.B.); (I.G.)
| | - Elena Volchkova
- Department of Infectious Diseases, Sechenov University, 119991 Moscow, Russia;
| | - Vladimir Gegechkori
- Department of Pharmaceutical and Toxicological Chemistry, Sechenov University, 119991 Moscow, Russia;
| | - Ilya Gordeychuk
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, 108819 Moscow, Russia; (E.B.); (I.G.)
- Department of Organization and Technology of Immunobiological Drugs, Sechenov University, 119991 Moscow, Russia
| | - Dieter Glebe
- National Reference Center for Hepatitis B Viruses and Hepatitis D Viruses, Institute of Medical Virology, Justus Liebig University of Giessen, 35392 Giessen, Germany;
| | - Dmitry Kostyushev
- National Medical Research Center of Tuberculosis and Infectious Diseases, Ministry of Health, 127994 Moscow, Russia; (S.B.); (A.K.); (V.C.)
- Scientific Center for Genetics and Life Sciences, Division of Biotechnology, Sirius University of Science and Technology, 354340 Sochi, Russia
| | - Vladimir Chulanov
- National Medical Research Center of Tuberculosis and Infectious Diseases, Ministry of Health, 127994 Moscow, Russia; (S.B.); (A.K.); (V.C.)
- Scientific Center for Genetics and Life Sciences, Division of Biotechnology, Sirius University of Science and Technology, 354340 Sochi, Russia
- Department of Infectious Diseases, Sechenov University, 119991 Moscow, Russia;
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Interferon-Induced Transmembrane Protein 3 Is a Virus-Associated Protein Which Suppresses Porcine Reproductive and Respiratory Syndrome Virus Replication by Blocking Viral Membrane Fusion. J Virol 2020; 94:JVI.01350-20. [PMID: 32999030 PMCID: PMC7925183 DOI: 10.1128/jvi.01350-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/10/2020] [Indexed: 11/23/2022] Open
Abstract
Porcine reproductive and respiratory syndrome (PRRS), which is caused by PRRS virus (PRRSV), is of great economic significance to the swine industry. Due to the complicated immune escape mechanisms of PRRSV, there are no effective vaccines or therapeutic drugs currently available against PRRS. Identification of cellular factors and underlying mechanisms that establish an effective antiviral state against PRRSV can provide unique strategies for developing antiviral vaccines or drugs. As an interferon (IFN)-stimulated gene, the role of IFN-induced transmembrane 3 (IFITM3) in PRRSV infection has not been reported as of yet. In the present study, it was shown that IFITM3 can exert a potent anti-PRRSV effect, and PRRS virions are trafficked to IFITM3-containing cell vesicles, where viral membrane fusion is impaired by cholesterol accumulation that is induced by IFITM3. Additionally, both endogenous and exogenous IFITM3 are incorporated into newly assembled progeny virions, and this decreased their intrinsic infectivity. Porcine reproductive and respiratory syndrome virus (PRRSV) infection eliminates production of type I interferons (IFNs) in host cells, which triggers an antiviral immune response through the induction of downstream IFN-stimulated genes (ISGs), thus escaping the fate of host-mediated clearance. The IFN-induced transmembrane 3 (IFITM3) has recently been identified as an ISG and plays a pivotal role against enveloped RNA viruses by restricting cell entry. However, the role of IFITM3 in PRRSV replication is unknown. The present study demonstrated that overexpression of IFITM3 suppresses PRRSV replication, while silencing of endogenous IFITM3 prominently promoted PRRSV replication. Additionally, it was shown that IFITM3 undergoes S-palmitoylation and ubiquitination modification, and both posttranslational modifications contribute to the anti-PRRSV activity of IFITM3. Further study showed that PRRSV particles are transported into endosomes and then into lysosomes during the early stages of infection, and confocal microscopy results revealed that PRRSV particles are transported to IFITM3-positive cellular vesicles. By using a single virus particle fluorescent labeling technique, we confirmed that IFITM3 can restrict PRRSV membrane fusion by inducing accumulation of cholesterol in cellular vesicles. Additionally, we found that both endogenous and exogenous IFITM3 are incorporated into newly producing PRRS virions and diminish viral intrinsic infectivity. By using cell coculture systems, we found that IFITM3 effectively restricted PRRSV intercellular transmission, which may have been caused by disrupted membrane fusion and reduced viral infectivity. In conclusion, our results demonstrate, for the first time, that swine IFITM3 interferes with the life cycle of PRRSV, and possibly other enveloped arteritis viruses, at multiple steps. IMPORTANCE Porcine reproductive and respiratory syndrome (PRRS), which is caused by PRRS virus (PRRSV), is of great economic significance to the swine industry. Due to the complicated immune escape mechanisms of PRRSV, there are no effective vaccines or therapeutic drugs currently available against PRRS. Identification of cellular factors and underlying mechanisms that establish an effective antiviral state against PRRSV can provide unique strategies for developing antiviral vaccines or drugs. As an interferon (IFN)-stimulated gene, the role of IFN-induced transmembrane 3 (IFITM3) in PRRSV infection has not been reported as of yet. In the present study, it was shown that IFITM3 can exert a potent anti-PRRSV effect, and PRRS virions are trafficked to IFITM3-containing cell vesicles, where viral membrane fusion is impaired by cholesterol accumulation that is induced by IFITM3. Additionally, both endogenous and exogenous IFITM3 are incorporated into newly assembled progeny virions, and this decreased their intrinsic infectivity.
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7
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Rahman K, Coomer CA, Majdoul S, Ding SY, Padilla-Parra S, Compton AA. Homology-guided identification of a conserved motif linking the antiviral functions of IFITM3 to its oligomeric state. eLife 2020; 9:58537. [PMID: 33112230 PMCID: PMC7665892 DOI: 10.7554/elife.58537] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 10/27/2020] [Indexed: 02/06/2023] Open
Abstract
The interferon-inducible transmembrane (IFITM) proteins belong to the Dispanin/CD225 family and inhibit diverse virus infections. IFITM3 reduces membrane fusion between cells and virions through a poorly characterized mechanism. Mutation of proline-rich transmembrane protein 2 (PRRT2), a regulator of neurotransmitter release, at glycine-305 was previously linked to paroxysmal neurological disorders in humans. Here, we show that glycine-305 and the homologous site in IFITM3, glycine-95, drive protein oligomerization from within a GxxxG motif. Mutation of glycine-95 (and to a lesser extent, glycine-91) disrupted IFITM3 oligomerization and reduced its antiviral activity against Influenza A virus. An oligomerization-defective variant was used to reveal that IFITM3 promotes membrane rigidity in a glycine-95-dependent and amphipathic helix-dependent manner. Furthermore, a compound which counteracts virus inhibition by IFITM3, Amphotericin B, prevented the IFITM3-mediated rigidification of membranes. Overall, these data suggest that IFITM3 oligomers inhibit virus-cell fusion by promoting membrane rigidity.
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Affiliation(s)
- Kazi Rahman
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, United States
| | - Charles A Coomer
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, United States.,Cellular Imaging Group, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Saliha Majdoul
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, United States
| | - Selena Y Ding
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, United States
| | - Sergi Padilla-Parra
- Cellular Imaging Group, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.,Department of Infectious Diseases, King's College London, Faculty of Life Sciences & Medicine, London, United Kingdom.,Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Alex A Compton
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, United States
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Zheng M, Zhao X, Zheng S, Chen D, Du P, Li X, Jiang D, Guo JT, Zeng H, Lin H. Bat SARS-Like WIV1 coronavirus uses the ACE2 of multiple animal species as receptor and evades IFITM3 restriction via TMPRSS2 activation of membrane fusion. Emerg Microbes Infect 2020; 9:1567-1579. [PMID: 32602823 PMCID: PMC7473123 DOI: 10.1080/22221751.2020.1787797] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Diverse SARS-like coronaviruses (SL-CoVs) have been identified from bats and other animal species. Like SARS-CoV, some bat SL-CoVs, such as WIV1, also use angiotensin converting enzyme 2 (ACE2) from human and bat as entry receptor. However, whether these viruses can also use the ACE2 of other animal species as their receptor remains to be determined. We report herein that WIV1 has a broader tropism to ACE2 orthologs than SARS-CoV isolate Tor2. Among the 9 ACE2 orthologs examined, human ACE2 exhibited the highest efficiency to mediate the infection of WIV1 pseudotyped virus. Our findings thus imply that WIV1 has the potential to infect a wide range of wild animals and may directly jump to humans. We also showed that cell entry of WIV1 could be restricted by interferon-induced transmembrane proteins (IFITMs). However, WIV1 could exploit the airway protease TMPRSS2 to partially evade the IFITM3 restriction. Interestingly, we also found that amphotericin B could enhance the infectious entry of SARS-CoVs and SL-CoVs by evading IFITM3-mediated restriction. Collectively, our findings further underscore the risk of exposure to animal SL-CoVs and highlight the vulnerability of patients who take amphotericin B to infection by SL-CoVs, including the most recently emerging (SARS-CoV-2).
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Affiliation(s)
- Mei Zheng
- Institute of Infectious Disease, Beijing Ditan Hospital, Capital Medical University, Beijing, People's Republic of China.,Beijing Key Laboratory of Emerging Infectious Disease, Beijing, People's Republic of China
| | - Xuesen Zhao
- Institute of Infectious Disease, Beijing Ditan Hospital, Capital Medical University, Beijing, People's Republic of China.,Beijing Key Laboratory of Emerging Infectious Disease, Beijing, People's Republic of China
| | - Shuangli Zheng
- Institute of Infectious Disease, Beijing Ditan Hospital, Capital Medical University, Beijing, People's Republic of China.,Beijing Key Laboratory of Emerging Infectious Disease, Beijing, People's Republic of China
| | - Danying Chen
- Institute of Infectious Disease, Beijing Ditan Hospital, Capital Medical University, Beijing, People's Republic of China.,Beijing Key Laboratory of Emerging Infectious Disease, Beijing, People's Republic of China
| | - Pengcheng Du
- Institute of Infectious Disease, Beijing Ditan Hospital, Capital Medical University, Beijing, People's Republic of China.,Beijing Key Laboratory of Emerging Infectious Disease, Beijing, People's Republic of China
| | - Xinglin Li
- Institute of Infectious Disease, Beijing Ditan Hospital, Capital Medical University, Beijing, People's Republic of China.,Beijing Key Laboratory of Emerging Infectious Disease, Beijing, People's Republic of China
| | - Dong Jiang
- Institute of Infectious Disease, Beijing Ditan Hospital, Capital Medical University, Beijing, People's Republic of China.,Beijing Key Laboratory of Emerging Infectious Disease, Beijing, People's Republic of China
| | - Ju-Tao Guo
- Baruch S. Blumberg Institute, Hepatitis B Foundation, Doylestown, PA, USA
| | - Hui Zeng
- Institute of Infectious Disease, Beijing Ditan Hospital, Capital Medical University, Beijing, People's Republic of China.,Beijing Key Laboratory of Emerging Infectious Disease, Beijing, People's Republic of China
| | - Hanxin Lin
- Department of Pathology and Laboratory Medicine, Western University, London, Canada
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9
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Abstract
Interferon-induced transmembrane (IFITM) proteins are encoded by many vertebrate species and exhibit antiviral activities against a wide range of viruses. IFITM3, when present in virus-producing cells, reduces the fusion potential of HIV-1 virions, but the mechanism is poorly understood. To define the breadth and mechanistic basis for the antiviral activity of IFITM3, we took advantage of a murine leukemia virus (MLV)-based pseudotyping system. By carefully controlling amounts of IFITM3 and envelope protein (Env) in virus-producing cells, we found that IFITM3 potently inhibits MLV infectivity when Env levels are limiting. Loss of infectivity was associated with defective proteolytic processing of Env and lysosomal degradation of the Env precursor. Ecotropic and xenotropic variants of MLV Env, as well as HIV-1 Env and vesicular stomatitis virus glycoprotein (VSV-G), are sensitive to IFITM3, whereas Ebola glycoprotein is resistant, suggesting that IFITM3 selectively inactivates certain viral glycoproteins. Furthermore, endogenous IFITM3 in human and murine cells negatively regulates MLV Env abundance. However, we found that the negative impact of IFITM3 on virion infectivity is greater than its impact on decreasing Env incorporation, suggesting that IFITM3 may impair Env function, as well as reduce the amount of Env in virions. Finally, we demonstrate that loss of virion infectivity mediated by IFITM3 is reversed by the expression of glycoGag, a murine retrovirus accessory protein previously shown to antagonize the antiviral activity of SERINC proteins. Overall, we show that IFITM3 impairs virion infectivity by regulating Env quantity and function but that enhanced Env expression and glycoGag confer viral resistance to IFITM3.IMPORTANCE The viral envelope glycoprotein, known as "Env" in Retroviridae, is found on the virion surface and facilitates virus entry into cells by mediating cell attachment and fusion. Env is a major structural component of retroviruses and is targeted by all arms of the immune response, including adaptive and innate immunity. Less is known about how cell-intrinsic immunity prevents retrovirus replication at the level of individual cells. Here, we show that cellular IFITM3 and IFITM2 inhibit the fusion potential of retroviral virions by inhibiting Env protein via a two-pronged mechanism. IFITM proteins inhibit Env abundance in cells and also impair its function when levels are low. The posttranslational block of retroviral Env function by IFITM proteins is likely to impede both exogenous and endogenous retrovirus replication. In support of a relevant role for IFITM3 in retrovirus control, the retroviral accessory protein glycoGag counteracts IFITM3 function to promote virus infectivity.
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10
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Winkler M, Gärtner S, Markus L, Hoffmann M, Nehlmeier I, Krawczak M, Sauermann U, Pöhlmann S. Role of rhesus macaque IFITM3(2) in simian immunodeficiency virus infection of macaques. PLoS One 2019; 14:e0224082. [PMID: 31682595 PMCID: PMC6827983 DOI: 10.1371/journal.pone.0224082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 10/04/2019] [Indexed: 11/19/2022] Open
Abstract
The experimental infection of rhesus macaques (rh) with simian immunodeficiency virus (SIV) is an important model for human immunodeficiency virus (HIV) infection of humans. The interferon-induced transmembrane protein 3 (IFITM3) inhibits HIV and SIV infection at the stage of host cell entry. However, it is still unclear to what extent the antiviral activity of IFITM3 observed in cell culture translates into inhibition of HIV/SIV spread in the infected host. We have shown previously that although rhIFITM3 inhibits SIV entry into cultured cells, polymorphisms in the rhIFITM3 gene are not strongly associated with viral load or disease progression in SIV infected macaques. Here, we examined whether rhIFITM3(2), which is closely related to rhIFITM3 at the sequence level, exerts antiviral activity and whether polymorphisms in the rhIFITM3(2) gene impact the course of SIV infection. We show that expression of rhIFITM3(2) is interferon-inducible and inhibits SIV entry into cells, although with reduced efficiency as compared to rhIFITM3. We further report the identification of 19 polymorphisms in the rhIFITM3(2) gene. However, analysis of a well characterized cohort of SIV infected macaques revealed that none of the polymorphisms had a significant impact upon the course of SIV infection. These results and our previous work suggest that polymorphisms in the rhIFITM3 and rhIFITM3(2) genes do not strongly modulate the course of SIV infection in macaques.
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Affiliation(s)
- Michael Winkler
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
- * E-mail: (SP); (MW)
| | - Sabine Gärtner
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
| | - Lara Markus
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
- Faculty of Biology and Psychology, University Göttingen, Göttingen, Germany
| | - Markus Hoffmann
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
| | - Inga Nehlmeier
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
| | - Michael Krawczak
- Institute of Medical Informatics and Statistics, Kiel University, Kiel, Germany
| | - Ulrike Sauermann
- Infection Models Unit, German Primate Center—Leibniz Institute for Primate Research, Göttingen, Germany
| | - Stefan Pöhlmann
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
- Faculty of Biology and Psychology, University Göttingen, Göttingen, Germany
- * E-mail: (SP); (MW)
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