1
|
Gianopulos KA, Makio AO, Pritchard SM, Cunha CW, Hull MA, Nicola AV. Herpes Simplex Virus 1 Glycoprotein B from a Hyperfusogenic Virus Mediates Enhanced Cell-Cell Fusion. Viruses 2024; 16:251. [PMID: 38400027 PMCID: PMC10892784 DOI: 10.3390/v16020251] [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: 12/05/2023] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
Herpes simplex virus 1 (HSV-1) causes significant morbidity and death in humans worldwide. Herpes simplex virus 1 has a complex fusion mechanism that is incompletely understood. The HSV-1 strain ANG has notable fusion and entry activities that distinguish it from wild type. HSV-1 ANG virions fused with the Vero cell surface at 4 °C and also entered cells more efficiently at 15 °C, relative to wild type HSV-1 strain KOS virions, consistent with a hyperfusogenic phenotype. Understanding the molecular basis for the unique entry and fusion activities of HSV-1 strain ANG will help decipher the HSV fusion reaction and entry process. Sequencing of HSV-1 ANG genes revealed multiple changes in gB, gC, gD, gH, and gL proteins relative to wild type HSV-1 strains. The ANG UL45 gene sequence, which codes for a non-essential envelope protein, was identical to wild type KOS. HSV-1 ANG gB, gD, and gH/gL were necessary and sufficient to mediate cell-cell fusion in a virus-free reporter assay. ANG gB, when expressed with wild type KOS gD and gH/gL, increased membrane fusion, suggesting that ANG gB has hyperfusogenic cell-cell fusion activity. Replacing the KOS gD, gH, or gL with the corresponding ANG alleles did not enhance cell-cell fusion. The novel mutations in the ANG fusion and entry glycoproteins provide a platform for dissecting the cascade of interactions that culminate in HSV fusion and entry.
Collapse
Affiliation(s)
- Katrina A. Gianopulos
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA; (K.A.G.); (A.O.M.); (C.W.C.)
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA
- Protein Biotechnology Graduate Training Program, Washington State University, Pullman, WA 99164, USA
| | - Albina O. Makio
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA; (K.A.G.); (A.O.M.); (C.W.C.)
- Protein Biotechnology Graduate Training Program, Washington State University, Pullman, WA 99164, USA
| | - Suzanne M. Pritchard
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA; (K.A.G.); (A.O.M.); (C.W.C.)
| | - Cristina W. Cunha
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA; (K.A.G.); (A.O.M.); (C.W.C.)
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA 99164, USA
| | - McKenna A. Hull
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA; (K.A.G.); (A.O.M.); (C.W.C.)
| | - Anthony V. Nicola
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA; (K.A.G.); (A.O.M.); (C.W.C.)
| |
Collapse
|
2
|
Zhong X, Zhang Y, Yuan M, Xu L, Luo X, Wu R, Xi Z, Li Y, Xu H. Prunella vulgaris polysaccharide inhibits herpes simplex virus infection by blocking TLR-mediated NF-κB activation. Chin Med 2024; 19:6. [PMID: 38185640 PMCID: PMC10773030 DOI: 10.1186/s13020-023-00865-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 11/22/2023] [Indexed: 01/09/2024] Open
Abstract
BACKGROUND Prunella vulgaris polysaccharide extracted by hot water and 30% ethanol precipitation (PVE30) was reported to possess potent antiviral effects against herpes simplex virus (HSV) infection. However, its anti-HSV mechanism has not yet been fully elucidated. PURPOSE This study aimed to investigate the potential mechanisms of PVE30 against HSV infection. METHODS Antiviral activity was evaluated by a plaque reduction assay, and the EC50 value was calculated. Immunofluorescence staining and heparin bead pull-down assays confirmed the interactions between PVE30 and viral glycoproteins. Real-time PCR was conducted to determine the mRNA levels of viral genes, including UL54, UL29, UL27, UL44, and US6, and the proinflammatory cytokines IL-6 and TNF-α. The protein expression of viral proteins (ICP27, ICP8, gB, gC, and gD), the activity of the TLR-NF-κB signalling pathway, and necroptotic-associated proteins were evaluated by Western blotting. The proportion of necroptotic cells was determined by flow cytometric analysis. RESULTS The P. vulgaris polysaccharide PVE30 was shown to compete with heparan sulfate for interaction with HSV surface glycoprotein B and gC, thus strongly inhibiting HSV attachment to cells. In addition, PVE30 downregulated the expression of IE genes, which subsequently downregulated the expression of E and L viral gene products, and thus effectively restricted the yield of progeny virus. Further investigation confirmed that PVE30 inhibited TLR2 and TLR3 signalling, leading to the effective suppression of NF-κB activation and IL-6 and TNF-α expression levels, and blocked HSV-1-induced necroptosis by reducing HSV-1-induced phosphorylation of MLKL. CONCLUSION Our results demonstrate that the P. vulgaris polysaccharide PVE30 is a potent anti-HSV agent that blocks TLR-mediated NF-κB activation.
Collapse
Affiliation(s)
- Xuanlei Zhong
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, No. 1200, Cailun Road, Shanghai, 201203, China
- Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai, China
| | - Yibo Zhang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, No. 1200, Cailun Road, Shanghai, 201203, China
- Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai, China
| | - Man Yuan
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, No. 1200, Cailun Road, Shanghai, 201203, China
- Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai, China
| | - Lin Xu
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, No. 1200, Cailun Road, Shanghai, 201203, China
- Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai, China
| | - Xiaomei Luo
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, No. 1200, Cailun Road, Shanghai, 201203, China
- Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai, China
| | - Rong Wu
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, No. 1200, Cailun Road, Shanghai, 201203, China
- Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai, China
| | - Zhichao Xi
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, No. 1200, Cailun Road, Shanghai, 201203, China
- Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai, China
| | - Yang Li
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, No. 1200, Cailun Road, Shanghai, 201203, China.
- Engineering Research Center of Shanghai Colleges for TCM New Drug Discovery, Shanghai, China.
| | - Hongxi Xu
- Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| |
Collapse
|
3
|
Gianopulos KA, Makio AO, Pritchard SM, Cunha CW, Hull MA, Nicola AV. Membrane fusion activity of herpes simplex virus 1 glycoproteins from a hyperfusogenic virus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.04.569993. [PMID: 38106075 PMCID: PMC10723375 DOI: 10.1101/2023.12.04.569993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Herpes simplex virus 1 (HSV-1) causes significant morbidity and death in humans worldwide. Herpes simplex virus 1 has a complex fusion mechanism that is incompletely understood. The HSV-1 strain ANG has notable fusion and entry activities that distinguish it from wild type. HSV-1 ANG virions fused with the Vero cell surface at 4°C and also entered cells more efficiently at 15°C relative to wild type virions, consistent with a hyperfusogenic phenotype. Understanding the molecular basis for the unique entry and fusion activities of HSV-1 strain ANG will help decipher the HSV fusion reaction and entry process. Sequencing of HSV-1 ANG genes revealed multiple changes in gB, gC, gD, gH, and gL proteins relative to wild type HSV-1 strains. The ANG UL45 gene sequence, which codes for a non-essential envelope protein, was identical to wild type. HSV-1 ANG gB, gD, and gH/gL were necessary and sufficient to mediate cell-cell fusion in a virus-free reporter assay. ANG gB, when expressed with wild type gD and gH/gL, increased membrane fusion, suggesting that ANG gB has hyperfusogenic cell-cell fusion activity. Replacing the wild type gD, gH, or gL with the corresponding ANG alleles did not enhance cell-cell fusion. Wild type gC is proposed to facilitate fusion and entry into epithelial cells by optimizing conformational changes in the fusion protein gB. ANG gC substitution or addition also had no effect on cell-cell fusion. The novel mutations in the ANG fusion and entry glycoproteins provide a platform for dissecting the cascade of interactions that culminate in HSV fusion and entry.
Collapse
|
4
|
Fan Q, Hippler DP, Yang Y, Longnecker R, Connolly SA. Multiple Sites on Glycoprotein H (gH) Functionally Interact with the gB Fusion Protein to Promote Fusion during Herpes Simplex Virus (HSV) Entry. mBio 2023; 14:e0336822. [PMID: 36629412 PMCID: PMC9973363 DOI: 10.1128/mbio.03368-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 01/12/2023] Open
Abstract
Enveloped virus entry requires fusion of the viral envelope with a host cell membrane. Herpes simplex virus 1 (HSV-1) entry is mediated by a set of glycoproteins that interact to trigger the viral fusion protein glycoprotein B (gB). In the current model, receptor-binding by gD signals a gH/gL heterodimer to trigger a refolding event in gB that fuses the membranes. To explore functional interactions between gB and gH/gL, we used a bacterial artificial chromosome (BAC) to generate two HSV-1 mutants that show a small plaque phenotype due to changes in gB. We passaged the viruses to select for restoration of plaque size and analyzed second-site mutations that arose in gH. HSV-1 gB was replaced either by gB from saimiriine herpesvirus 1 (SaHV-1) or by a mutant form of HSV-1 gB with three alanine substitutions in domain V (gB3A). To shift the selective pressure away from gB, the gB3A virus was passaged in cells expressing gB3A. Sequencing of passaged viruses identified two interesting mutations in gH, including gH-H789Y in domain IV and gH-S830N in the cytoplasmic tail (CT). Characterization of these gH mutations indicated they are responsible for the enhanced plaque size. Rather than being globally hyperfusogenic, both gH mutations partially rescued function of the specific gB version present during their selection. These sites may represent functional interaction sites on gH/gL for gB. gH-H789 may alter the positioning of a membrane-proximal flap in the gH ectodomain, whereas gH-S830 may contribute to an interaction between the gB and gH CTs. IMPORTANCE Enveloped viruses enter cells by fusing their envelope with the host cell membrane. Herpes simplex virus 1 (HSV-1) entry requires the coordinated interaction of several viral glycoproteins, including gH/gL and gB. gH/gL and gB are essential for virus replication and both proteins are targets of neutralizing antibodies. gB fuses the membranes after being activated by gH/gL, but the details of how gH/gL activates gB are not known. This study examined the gH/gL-gB interaction using HSV-1 mutants that displayed reduced virus entry due to changes in gB. The mutant viruses were grown over time to select for additional mutations that could partially restore entry. Two mutations in gH (H789Y and S830N) were identified. The positions of the mutations in gH/gL may represent sites that contribute to gB activation during virus entry.
Collapse
Affiliation(s)
- Qing Fan
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Daniel P. Hippler
- Department of Health Sciences, DePaul University, Chicago, Illinois, USA
- Department of Biological Sciences, DePaul University, Chicago, Illinois, USA
| | - Yueqi Yang
- Yuanpei College, Peking University, Beijing, China
| | - Richard Longnecker
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Sarah A. Connolly
- Department of Health Sciences, DePaul University, Chicago, Illinois, USA
- Department of Biological Sciences, DePaul University, Chicago, Illinois, USA
| |
Collapse
|