scholarly journals The Fusion Loops of the Initial Prefusion Conformation of Herpes Simplex Virus 1 Fusion Protein Point Toward the Membrane

mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Juan Fontana ◽  
Doina Atanasiu ◽  
Wan Ting Saw ◽  
John R. Gallagher ◽  
Reagan G. Cox ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Fusion Protein ◽  
Surface Protein ◽  
Skin Lesions ◽  
Enveloped Viruses ◽  
Host Membrane ◽  
Simplex Virus ◽  
Viral Surface Protein ◽  
Viral Surface

ABSTRACTAll enveloped viruses, including herpesviruses, must fuse their envelope with the host membrane to deliver their genomes into target cells, making this essential step subject to interference by antibodies and drugs. Viral fusion is mediated by a viral surface protein that transits from an initial prefusion conformation to a final postfusion conformation. Strikingly, the prefusion conformation of the herpesvirus fusion protein, gB, is poorly understood. Herpes simplex virus (HSV), a model system for herpesviruses, causes diseases ranging from mild skin lesions to serious encephalitis and neonatal infections. Using cryo-electron tomography and subtomogram averaging, we have characterized the structure of the prefusion conformation and fusion intermediates of HSV-1 gB. To this end, we have set up a system that generates microvesicles displaying full-length gB on their envelope. We confirmed proper folding of gB by nondenaturing electrophoresis-Western blotting with a panel of monoclonal antibodies (MAbs) covering all gB domains. To elucidate the arrangement of gB domains, we labeled them by using (i) mutagenesis to insert fluorescent proteins at specific positions, (ii) coexpression of gB with Fabs for a neutralizing MAb with known binding sites, and (iii) incubation of gB with an antibody directed against the fusion loops. Our results show that gB starts in a compact prefusion conformation with the fusion loops pointing toward the viral membrane and suggest, for the first time, a model for gB’s conformational rearrangements during fusion. These experiments further illustrate how neutralizing antibodies can interfere with the essential gB structural transitions that mediate viral entry and therefore infectivity.IMPORTANCEThe herpesvirus family includes herpes simplex virus (HSV) and other human viruses that cause lifelong infections and a variety of diseases, like skin lesions, encephalitis, and cancers. As enveloped viruses, herpesviruses must fuse their envelope with the host membrane to start an infection. This process is mediated by a viral surface protein that transitions from an initial conformation (prefusion) to a final, more stable, conformation (postfusion). However, the prefusion conformation of the herpesvirus fusion protein (gB) is poorly understood. To elucidate the structure of the prefusion conformation of HSV type 1 gB, we have employed cryo-electron microscopy to study gB molecules expressed on the surface of vesicles. Using different approaches to label gB’s domains allowed us to model the structures of the prefusion and intermediate conformations of gB. Overall, our findings enhance our understanding of HSV fusion and lay the groundwork for the development of new ways to prevent and block HSV infection.

Effects of Analgesics on Delayed Postherpetic Pain in Mice

2002 ◽  
Vol 96 (5) ◽  
pp. 1168-1174 ◽  
Author(s):  
Ichiro Takasaki ◽  
Atsushi Sasaki ◽  
Tsugunobu Andoh ◽  
Hiroshi Nojima ◽  
Kimiyasu Shiraki ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Postherpetic Neuralgia ◽  
Herpes Simplex Virus Infection ◽  
Skin Lesions ◽  
Cutaneous Lesions ◽  
Acyclovir Treatment ◽  
Simplex Virus ◽  
Von Frey Filaments

Background Postherpetic neuralgia is pain that persists long after the disappearance of the cutaneous lesions of herpes zoster. However, the mechanisms of this delayed pain are unclear. Herpes simplex virus infection induces cutaneous lesions and pain-related responses in mice. The authors examined whether such responses would persist after the disappearance of the cutaneous lesions and whether some analgesics would be effective against them. Methods Female BALB/c mice were inoculated with herpes simplex virus type 1 on the unilateral hind paw. Pain-related responses of hind paw were determined using von Frey filaments. Beginning 5 days after inoculation, mice were given perorally the antiherpes agent acyclovir five times a day for 7 days. Effects of morphine (3-5 mg/kg subcutaneously), gabapentin (30-100 mg/kg perorally), mexiletine (10-30 mg/kg intraperitoneally), and diclofenac (30 mg/kg intraperitoneally) on pain-related responses were examined on days 25-35 after inoculation. Results Viral inoculation induced cutaneous lesions and pain-related responses beginning on day 5 after inoculation. Acyclovir treatment healed all skin lesions by day 15 after inoculation. Approximately half of the mice given acyclovir showed pain-related responses at least until day 40 after inoculation. Morphine, gabapentin, and mexiletine dose-dependently inhibited pain-related responses, but diclofenac had no effects. Conclusions The authors show a mouse model of delayed postherpetic pain. This may be useful for manifesting the mechanisms of postherpetic neuralgia and the factors contributing to the transition from acute herpetic pain to delayed postherpetic pain. This may also be useful for the development of new analgesics against postherpetic neuralgia.

scholarly journals Herpes Simplex Virus Type 1 Corneal Infection Results in Periocular Disease by Zosteriform Spread

2001 ◽  
Vol 75 (11) ◽  
pp. 5069-5075 ◽  
Author(s):  
Bretton C. Summers ◽  
Todd P. Margolis ◽  
David A. Leib
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Skin Lesions ◽  
Ocular Infection ◽  
Trigeminal Ganglia ◽  
Corneal Infection ◽  
Recombinant Viruses ◽  
Viral Spread ◽  
Reporter Activity ◽  
Simplex Virus

ABSTRACT In humans and animal models of herpes simplex virus infection, zosteriform skin lesions have been described which result from anterograde spread of the virus following invasion of the nervous system. Such routes of viral spread have not been fully examined following corneal infection, and the possible pathologic consequences of such spread are unknown. To investigate this, recombinant viruses expressing reporter genes were generated to quantify and correlate gene expression with replication in eyes, trigeminal ganglia, and periocular tissue. Reporter activity peaked in eyes 24 h postinfection and rapidly fell to background levels by 48 h despite the continued presence of viral titers. Reporter activity rose in the trigeminal ganglia at 60 h and peaked at 72 h, concomitant with the appearance and persistence of infectious virus. Virus was present in the periocular skin from 24 h despite the lack of significant reporter activity until 84 h postinfection. This detection of reporter activity was followed by the onset of periocular disease on day 4. Corneal infection with a thymidine kinase-deleted reporter virus displayed a similar profile of reporter activity and viral titer in the eyes, but little or no detectable activity was observed in trigeminal ganglia or periocular tissue. In addition, no periocular disease symptoms were observed. These findings demonstrate that viral infection of periocular tissue and subsequent disease development occurs by zosteriform spread from the cornea to the periocular tissue via the trigeminal ganglion rather than by direct spread from cornea to the periocular skin. Furthermore, clinical evidence is discussed suggesting that a similar mode of spreading and disease occurs in humans following primary ocular infection.

scholarly journals Functional and Physical Interactions of the Herpes Simplex Virus Type 1 UL20 Membrane Protein with Glycoprotein K

2008 ◽  
Vol 82 (13) ◽  
pp. 6310-6323 ◽  
Author(s):  
Timothy P. Foster ◽  
Vladimir N. Chouljenko ◽  
K. G. Kousoulas
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Fusion Protein ◽  
Protein Interactions ◽  
Herpes Simplex Virus Type ◽  
Protein Protein Interactions ◽  
Glycoprotein K ◽  
Er Retention ◽  
Simplex Virus

ABSTRACT Herpes simplex virus type 1 glycoprotein K (gK) and the UL20 protein (UL20p) are coordinately transported to the trans-Golgi network (TGN) and cell surfaces and are required for cytoplasmic virion envelopment at the TGN. In addition, cell surface expression of gK and UL20p is required for virus-induced cell fusion. Previously, confocal microscopy colocalization and intracellular transport experiments strongly suggested direct protein-protein interactions between gK and UL20p. Direct protein-protein interactions between gK and UL20p were demonstrated through reciprocal coimmunoprecipitation experiments, as well as with glutathione S-transferase (GST) pull-down experiments. A fusion protein consisting of the amino-terminal 66 amino acids of UL20p fused in-frame with GST was expressed in Escherichia coli and purified via glutathione column chromatography. Precipitation of GST-UL20p from mixtures of GST-UL20p fusion protein with cellular extracts containing gK specifically coprecipitated gK but not other viral glycoproteins. The purified UL20p-GST fusion protein reacted with all gK-associated protein species. It was concluded that the amino terminus of UL20p, most likely, interacted with gK domain III, which is predicted to lie intracellularly. UL20p-gK domain-specific interactions must serve important functions in the coordinate transport of UL20p and gK to the TGN, because retention of UL20p in the endoplasmic reticulum (ER) via the addition of an ER retention signal at the carboxyl terminus of UL20p forced the ER retention of gK and drastically inhibited intracellular virion envelopment and virus-induced cell fusion.

Replication-Competent Herpes simplex Virus Type 1 Mutant Expressing an Autofluorescent Glycoprotein H Fusion Protein

Intervirology ◽  
2001 ◽  
Vol 44 (4) ◽  
pp. 232-242 ◽  
Author(s):  
E.U. Lorentzen ◽  
B.R. Eing ◽  
W. Hafezi ◽  
R. Manservigi ◽  
J.E. Kühn
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Fusion Protein ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Glycoprotein H ◽  
Simplex Virus

scholarly journals Herpes Simplex Virus Glycoprotein C Regulates Low-pH Entry

mSphere ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Tri Komala Sari ◽  
Katrina A. Gianopulos ◽  
Darin J. Weed ◽  
Seth M. Schneider ◽  
Suzanne M. Pritchard ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Fusion Protein ◽  
Conformational Changes ◽  
Low Ph ◽  
Cell Entry ◽  
Epidermal Keratinocytes ◽  
Herpes Simplex Viruses ◽  
Herpes Simplex Virus Glycoprotein ◽  
Simplex Virus

ABSTRACT Herpes simplex viruses (HSVs) cause significant morbidity and mortality in humans worldwide. Herpesviruses mediate entry by a multicomponent virus-encoded machinery. Herpesviruses enter cells by endosomal low-pH and pH-neutral mechanisms in a cell-specific manner. HSV mediates cell entry via the envelope glycoproteins gB and gD and the heterodimer gH/gL regardless of pH or endocytosis requirements. Specifics concerning HSV envelope proteins that function selectively in a given entry pathway have been elusive. Here, we demonstrate that gC regulates cell entry and infection by a low-pH pathway. Conformational changes in the core herpesviral fusogen gB are critical for membrane fusion. The presence of gC conferred a higher pH threshold for acid-induced antigenic changes in gB. Thus, gC may selectively facilitate low-pH entry by regulating conformational changes in the fusion protein gB. We propose that gC modulates the HSV fusion machinery during entry into pathophysiologically relevant cells, such as human epidermal keratinocytes. IMPORTANCE Herpesviruses are ubiquitous pathogens that cause lifelong latent infections and that are characterized by multiple entry pathways. We propose that herpes simplex virus (HSV) gC plays a selective role in modulating HSV entry, such as entry into epithelial cells, by a low-pH pathway. gC facilitates a conformational change of the main fusogen gB, a class III fusion protein. We propose a model whereby gC functions with gB, gD, and gH/gL to allow low-pH entry. In the absence of gC, HSV entry occurs at a lower pH, coincident with trafficking to a lower pH compartment where gB changes occur at more acidic pHs. This report identifies a new function for gC and provides novel insight into the complex mechanism of HSV entry and fusion.

scholarly journals In VivoAnti-Herpes Simplex Virus Activity of a Sulfated Derivative of Agaricus brasiliensis Mycelial Polysaccharide

2013 ◽  
Vol 57 (6) ◽  
pp. 2541-2549 ◽  
Author(s):  
F. T. G. S. Cardozo ◽  
I. V. Larsen ◽  
E. V. Carballo ◽  
G. Jose ◽  
R. A. Stern ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Sexual Transmission ◽  
Skin Lesions ◽  
Content Type ◽  
Agaricus Brasiliensis ◽  
Infection Models ◽  
Spread F ◽  
Simplex Virus ◽  
Viral Titers

ABSTRACTAgaricus brasiliensis(syn.A. subrufescens), a basidiomycete fungus native to the Atlantic forest in Brazil, contains cell walls rich in glucomannan polysaccharides. The β-(1→2)-gluco-β-(1→3)-mannan was isolated fromA. brasiliensismycelium, chemically modified by sulfation, and named MI-S. MI-S has multiple mechanisms of action, including inhibition of herpes simplex virus (HSV) attachment, entry, and cell-to-cell spread (F. T. G. S. Cardozo, C. M. Camelini, A. Mascarello, M. J. Rossi, R. J. Nunes, C. R. Barardi, M. M. de Mendonça, and C. M. O. Simões, Antiviral Res. 92:108–114, 2011). The antiherpetic efficacy of MI-S was assessed in murine ocular, cutaneous, and genital infection models of HSV. Groups of 10 mice were infected with HSV-1 (strain KOS) or HSV-2 (strain 333). MI-S was given either topically or by oral gavage under various pre- and posttreatment regimens, and the severity of disease and viral titers in ocular and vaginal samples were determined. No toxicity was observed in the uninfected groups treated with MI-S. The topical and oral treatments with MI-S were not effective in reducing ocular disease. Topical application of MI-S on skin lesions was also not effective, but cutaneously infected mice treated orally with MI-S had significantly reduced disease scores (P< 0.05) after day 9, suggesting that healing was accelerated. Vaginal administration of MI-S 20 min before viral challenge reduced the mean disease scores on days 5 to 9 (P< 0.05), viral titers on day 1 (P< 0.05), and mortality (P< 0.0001) in comparison to the control groups (untreated and vehicle treated). These results show that MI-S may be useful as an oral agent to reduce the severity of HSV cutaneous and mucosal lesions and, more importantly, as a microbicide to block sexual transmission of HSV-2 genital infections.

scholarly journals Multi-organ involvement secondary to varicella zoster virus, herpes simplex virus and cytomegalovirus in an immunocompromised patient

2019 ◽  
Vol 12 (3) ◽  
pp. e228150 ◽  
Author(s):  
Ripal Jariwala ◽  
Kristen Zeitler ◽  
Nicole D Riddle ◽  
Chakrapol Sriaroon
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Varicella Zoster Virus ◽  
Immunocompromised Patient ◽  
Case Reports ◽  
Skin Lesions ◽  
Viral Reactivation ◽  
Organ Involvement ◽  
Varicella Zoster ◽  
Simplex Virus

The use of immunosuppressing agents can act as a catalyst for viral reactivation, promoting systemic infection with organ involvement. Current literature remains sparse on this topic but does provide individual case reports involving single viruses. We present the case of an immunocompromised patient with skin lesions, pancreatitis, colitis and hepatitis. Work-up revealed varicella zoster virus, which likely put the patient at risk for multi-organ involvement, as well as clinical suspicion of other implicated viruses, specifically herpes simplex virus and cytomegalovirus. A high clinical index of suspicion along with biopsy guidance for viral involvement in immunocompromised patients is crucial for early diagnosis and treatment of these conditions.

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