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Thannickal SA, Battini L, Spector SN, Noval MG, Álvarez DE, Stapleford KA. Changes in the chikungunya virus E1 glycoprotein domain II and hinge influence E2 conformation, infectivity, and virus-receptor interactions. J Virol 2024:e0067924. [PMID: 38842335 DOI: 10.1128/jvi.00679-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 05/14/2024] [Indexed: 06/07/2024] Open
Abstract
In a previous study to understand how the chikungunya virus (CHIKV) E1 glycoprotein β-strand c functions, we identified several attenuating variants at E1 residue V80 and the emergence of second-site mutations in the fusion loop (E1-M88L) and hinge region (E1-N20Y) with the V80 variants in vivo. The emergence of these mutations led us to question how changes in E1 may contribute to CHIKV infection at the molecular level. Here, we use molecular dynamics to understand how changes in the E1 glycoprotein may influence the CHIKV glycoprotein E1-E2 complex. We found that E1 domain II variants lead to E2 conformational changes, allowing us to hypothesize that emerging variants E1-M88L and E1-N20Y could also change E2 conformation and function. We characterized CHIKV E1-M88L and E1-N20Y in vitro and in vivo to understand how these regions of the E1 glycoprotein contribute to host-specific infection. We found that CHIKV E1-N20Y enhanced infectivity in mosquito cells, while the CHIKV E1-M88L variant enhanced infectivity in both BHK-21 and C6/36 cells and led to changes in viral cholesterol-dependence. Moreover, we found that E1-M88L and E1-N20Y changed E2 conformation, heparin binding, and interactions with the receptor Mxra8. Interestingly, the CHIKV E1-M88L variant increased replication in Mxra8-deficient mice compared to WT CHIKV, yet was attenuated in mouse fibroblasts, suggesting that residue E1-M88 may function in a cell-type-dependent entry. Taken together, these studies show that key residues in the CHIKV E1 domain II and hinge region function through changes in E1-E2 dynamics to facilitate cell- and host-dependent entry.IMPORTANCEArboviruses are significant global public health threats, and their continued emergence around the world highlights the need to understand how these viruses replicate at the molecular level. The alphavirus glycoproteins are critical for virus entry in mosquitoes and mammals, yet how these proteins function is not completely understood. Therefore, it is critical to dissect how distinct glycoprotein domains function in vitro and in vivo to address these gaps in our knowledge. Here, we show that changes in the CHIKV E1 domain II and hinge alter E2 conformations leading to changes in virus-receptor and -glycosaminoglycan interactions and cell-specific infection. These results highlight that adaptive changes in E1 can have a major effect on virus attachment and entry, furthering our knowledge of how alphaviruses infect mammals and insects.
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Affiliation(s)
- Sara A Thannickal
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Leandro Battini
- Laboratorio de Química Medicinal, Centro de Investigaciones en Bionanociencias (CIBON), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Investigaciones Biotecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de San Martín, San Martín, Argentina
| | - Sophie N Spector
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Maria G Noval
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Diego E Álvarez
- Instituto de Investigaciones Biotecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de San Martín, San Martín, Argentina
| | - Kenneth A Stapleford
- Department of Microbiology, New York University Grossman School of Medicine, New York, New York, USA
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Chen H, Phuektes P, Yeo LS, Wong YH, Lee RCH, Yi B, Hou X, Liu S, Cai Y, Chu JJH. Attenuation of neurovirulence of chikungunya virus by a single amino acid mutation in viral E2 envelope protein. J Biomed Sci 2024; 31:8. [PMID: 38229040 DOI: 10.1186/s12929-024-00995-x] [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: 09/28/2023] [Accepted: 01/05/2024] [Indexed: 01/18/2024] Open
Abstract
BACKGROUND Chikungunya virus (CHIKV) has reemerged as a major public health concern, causing chikungunya fever with increasing cases and neurological complications. METHODS In the present study, we investigated a low-passage human isolate of the East/ Central/South African (ECSA) lineage of CHIKV strain LK(EH)CH6708, which exhibited a mix of small and large viral plaques. The small and large plaque variants were isolated and designated as CHIKV-SP and CHIKV-BP, respectively. CHIKV-SP and CHIKV-BP were characterized in vitro and in vivo to compare their virus production and virulence. Additionally, whole viral genome analysis and reverse genetics were employed to identify genomic virulence factors. RESULTS CHIKV-SP demonstrated lower virus production in mammalian cells and attenuated virulence in a murine model. On the other hand, CHIKV-BP induced higher pro-inflammatory cytokine levels, compromised the integrity of the blood-brain barrier, and led to astrocyte infection in mouse brains. Furthermore, the CHIKV-SP variant had limited transmission potential in Aedes albopictus mosquitoes, likely due to restricted dissemination. Whole viral genome analysis revealed multiple genetic mutations in the CHIKV-SP variant, including a Glycine (G) to Arginine (R) mutation at position 55 in the viral E2 glycoprotein. Reverse genetics experiments confirmed that the E2-G55R mutation alone was sufficient to reduce virus production in vitro and virulence in mice. CONCLUSIONS These findings highlight the attenuating effects of the E2-G55R mutation on CHIKV pathogenicity and neurovirulence and emphasize the importance of monitoring this mutation in natural infections.
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Affiliation(s)
- Huixin Chen
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Patchara Phuektes
- Division of Pathobiology, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Li Sze Yeo
- School of Applied Science, Republic Polytechnic, Singapore, Singapore
| | - Yi Hao Wong
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Regina Ching Hua Lee
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Bowen Yi
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Xinjun Hou
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Sen Liu
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
| | - Yu Cai
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Justin Jang Hann Chu
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Collaborative and Translation Unit for HFMD, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
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Thannickal SA, Battini L, Spector SN, Noval MG, Álvarez DE, Stapleford KA. The chikungunya virus E1 glycoprotein fusion loop and hinge alter glycoprotein dynamics leading to cell and host specific changes in infectivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.03.565585. [PMID: 37961096 PMCID: PMC10635133 DOI: 10.1101/2023.11.03.565585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Alphaviruses infect both mammals and insects, yet the distinct mechanisms that alphaviruses use to infect different hosts are not well defined. In this study, we characterize CHIKV E1 variants in the fusion loop (E1-M88L) and hinge region (E1-N20Y) in vitro and in vivo to understand how these regions of the E1 glycoprotein contribute to host-specific infection. Through cell culture assays, we found that CHIKV E1-N20Y enhanced infectivity in mosquito cells while the CHIKV E1-M88L variant enhanced virus binding and infectivity in both BHK-21 and C6/36 cells, and led to changes in the virus cholesterol-dependence in BHK-21 cells. Given these in vitro results and that residue E1-M88L is in a defined Mxra8 interacting domain, we hypothesized that this residue may be important for receptor usage. However, while the CHIKV E1-M88L variant increased replication in Mxra8-deficient mice compared to WT CHIKV, it was attenuated in vitro in mouse fibroblasts, suggesting that residue E1-M88 may function in a cell-type dependent manner to alter entry. Finally, using molecular dynamics to understand how potential changes in the E1 glycoprotein may impact the CHIKV glycoprotein E1-E2 complex, we found that E1-M88L and other E1 domain II variants lead to changes in both E1 and E2 dynamics. Taken together, these studies show that key residues in the CHIKV E1 fusion loop and hinge region function through changes in E1-E2 dynamics to facilitate cell- and host-dependent entry. Importance Arthropod-borne viruses (arboviruses) are significant global public health threats, and their continued emergence around the world highlights the need to understand how these viruses replicate at the molecular level. The alphavirus class II glycoproteins are critical for virus entry in mosquitoes and mammals, yet how these proteins function is not completely understood. Therefore, to address these gaps in our knowledge, it is critical to dissect how distinct glycoprotein domains function in vitro and in vivo . Here, we show that changes in the CHIKV E1 fusion loop and hinge contribute to host-specific entry and E1-E2 dynamics, furthering our knowledge of how alphaviruses infect mammals and insects.
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