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Huang S, Shi PD, Fan XX, Yang Y, Qin CF, Zhao H, Shi L, Ci Y. The glycosylation deficiency of flavivirus NS1 attenuates virus replication through interfering with the formation of viral replication compartments. J Biomed Sci 2024; 31:60. [PMID: 38849802 PMCID: PMC11157723 DOI: 10.1186/s12929-024-01048-z] [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: 12/04/2023] [Accepted: 05/28/2024] [Indexed: 06/09/2024] Open
Abstract
BACKGROUND Flavivirus is a challenge all over the world. The replication of flavivirus takes place within membranous replication compartments (RCs) derived from endoplasmic reticulum (ER). Flavivirus NS1 proteins have been proven essential for the formation of viral RCs by remodeling the ER. The glycosylation of flavivirus NS1 proteins is important for viral replication, yet the underlying mechanism remains unclear. METHODS HeLa cells were used to visualize the ER remodeling effects induced by NS1 expression. ZIKV replicon luciferase assay was performed with BHK-21 cells. rZIKV was generated from BHK-21 cells and the plaque assay was done with Vero Cells. Liposome co-floating assay was performed with purified NS1 proteins from 293T cells. RESULTS We found that the glycosylation of flavivirus NS1 contributes to its ER remodeling activity. Glycosylation deficiency of NS1, either through N-glycosylation sites mutations or tunicamycin treatment, compromises its ER remodeling activity and interferes with viral RCs formation. Disruption of NS1 glycosylation results in abnormal aggregation of NS1, rather than reducing its membrane-binding activity. Consequently, deficiency in NS1 glycosylation impairs virus replication. CONCLUSIONS In summary, our results highlight the significance of NS1 glycosylation in flavivirus replication and elucidate the underlying mechanism. This provides a new strategy for combating flavivirus infections.
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Affiliation(s)
- Shuhan Huang
- State Key Laboratory of Common Mechanism Research for Major Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Pan-Deng Shi
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Xiao-Xuan Fan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Yang Yang
- State Key Laboratory of Common Mechanism Research for Major Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Cheng-Feng Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Hui Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China.
| | - Lei Shi
- State Key Laboratory of Common Mechanism Research for Major Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China.
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China.
| | - Yali Ci
- State Key Laboratory of Common Mechanism Research for Major Diseases, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China.
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences; and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China.
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Fendereski M, Ming H, Jiang Z, Guo YL. Mouse Trophoblast Cells Have Attenuated Responses to TNF-α and IFN-γ and Can Avoid Synergic Cytotoxicity of the Two Cytokines. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:346-354. [PMID: 38054905 PMCID: PMC10843640 DOI: 10.4049/jimmunol.2300210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 11/09/2023] [Indexed: 12/07/2023]
Abstract
TNF-α and IFN-γ are two inflammatory cytokines that play critical roles in immune responses, but they can also negatively affect cell proliferation and viability. In particular, the combination of the two cytokines (TNF-α/IFN-γ) synergistically causes cytotoxicity in many cell types. We recently reported that mouse embryonic stem cells (ESCs) isolated from the blastocyst stage embryo do not respond to TNF-α and have limited response to IFN-γ, thereby avoiding TNF-α/IFN-γ cytotoxicity. The current study expanded our investigation to mouse trophoblast stem cells (TSCs) and their differentiated trophoblasts (TSC-TBs), the precursors and the differentiated cells of the placenta, respectively. In this study, we report that the combination of TNF-α/IFN-γ does not show the cytotoxicity to TSCs and TSC-TBs that otherwise effectively kills fibroblasts, similar to ESCs. Although ESCs, TSCs, and TSC-TBs are dramatically different in their growth rate, morphology, and physiological functions, they nevertheless share a similarity in being able to avoid TNF-α/IFN-γ cytotoxicity. We propose that this unique immune property may serve as a protective mechanism that limits cytokine cytotoxicity in the blastocyst. With molecular and cellular approaches and genome-wide transcriptomic analysis, we have demonstrated that the attenuated NF-κB and STAT1 transcription activation is a limiting factor that restricts the effect of TNF-α/IFN-γ on TSCs and TSC-TBs.
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Affiliation(s)
- Mona Fendereski
- Cell and Molecular Biology Program, University of Southern Mississippi, Hattiesburg, MS 39406
| | - Hao Ming
- Department of Animal Sciences, Genetics Institute, University of Florida, Gainesville, FL 32608
| | - Zongliang Jiang
- Department of Animal Sciences, Genetics Institute, University of Florida, Gainesville, FL 32608
| | - Yan-Lin Guo
- Cell and Molecular Biology Program, University of Southern Mississippi, Hattiesburg, MS 39406
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Neupane B, Bai F. Quantification of West Nile Virus by Plaque-Forming Assay. Methods Mol Biol 2023; 2585:9-14. [PMID: 36331760 DOI: 10.1007/978-1-0716-2760-0_2] [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] [Indexed: 06/16/2023]
Abstract
The plaque-forming assay is a gold standard technique to determine the concentration of infectious viral particles. In this assay, lytic viruses infect and lyse the cells but are immobilized due to the presence of an agarose-containing overlay medium. The progeny viruses can only spread locally to and kill the adjacent cells and finally form a clear zone or plaque after staining the live cells. The number of plaques formed can be theoretically considered as the initial number of the infectious viral particles present in the sample and hence can be expressed as plaque-forming units (PFU) in a volume of the sample. Here, we provide a step-by-step method to carry out a plaque-forming assay to determine the titer of West Nile virus in a cell culture medium, which also can be adapted to other lytic viruses of eukaryotic cells.
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Affiliation(s)
- Biswas Neupane
- Department of Cell and Molecular Biology, Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Fengwei Bai
- Department of Cell and Molecular Biology, Center for Molecular and Cellular Biosciences, The University of Southern Mississippi, Hattiesburg, MS, USA.
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