The goal of this renewal application is to determine if blocking the mechanisms involved in intracellular HSV-1 gK processing and trafficking to the cell surface reduces virus replication and infectivity and thereby HSV-1- induced corneal scarring (CS). It is well established that HSV-1-induced CS is the result of virus-induced immune responses although the identity of the pathogenic responses is controversial. Similarly, the HSV-1 gene(s) involved in eye disease is not yet known although several lines of evidence indicate that the HSV-1 glycoprotein, gK plays a crucial role in replication and infectivity as exemplified by the inability of HSV-1 gK mutants to grow in cells lacking gK as they fail to acquire a cytoplasmic envelope efficiently and are unable to infect and establish latency in neurons. Our work shows that: (1) Deletion of gK results in reductions in virus yield, plaque size and translocation of the virus from the cytoplasm to the extracellular space; (ii) An 8mer peptide within the cleaved gK signal sequence is an immunodominant stimulatory region that upregulates T cell-responses in the cornea leading to exacerbation of CS; and (iii) Cell surface expression of gK is required for exacerbation of CS in ocularly infected mice. Thus, we examined the mechanisms that regulate gK intracellular processing and cell surface expression and in the current funding period have shown that binding of gK to signal peptide peptidase (SPP), an ER protein, is essential for HSV-1 infectivity both in vitro and in vivo. Preliminary dat further suggest that the 5' region of gK mediates its binding to SPP and binding of gK to HSV-1 UL20 mediates gK surface expression and is required for HSV-1-induced CS. These data suggest novel potential therapeutic targets for prevention of ocular HSV-1 infection and HSV-1-induced CS. We will test a hypothetical model in which the pathogenic effects of gK during primary ocular infection are mediated by two inter-related mechanisms: (i) gK binds to SPP leading to higher levels of virus replication; and (ii) gK binds to UL20, which is required for the surface expression of gK necessary for gK-induced CS and greater levels of eye disease. We will: (1) Test whether SPP plays a major role in HSV-1 infectivity in vitro and in vivo by: (i) Fin mapping the region of gK involved in SPP binding, and construction of a recombinant HSV-1 expressing a mutant form of gK that does not bind to SPP to determine if it fails to exacerbate CS in mice; and (ii) generation of SPP knockout mice to determine if they are protected from eye disease, virus replication and latency. (2) Test whether binding of UL20 to gK and the Golgi-specific DHHC zinc finger protein (GODZ), are required for proper cell surface expression of gK. We will determine if UL20 binds to gK and if UL20 binds to GODZ using pull-down assays and immunostaining; determine the function of GODZ in vitro and in vivo using GODZ knockout mice that we have generated; and determine the effects of disruption of these key binding events, alone and in combination, on the intracellular localization of gK and its cleaved products. Preliminary data is presented that indicate the feasibility of the proposed approaches. CLINICAL SIGNIFICANCE: HSV-1-induced CS can lead to blindness and is the leading cause of infectious blindness in developed countries but there is no FDA approved drug for its treatment. The proposed studies represent an entirely novel approach to the development of effective strategies for the prevention and treatment of this disease.

Public Health Relevance

HSV-1 causes eye disease and can lead to blindness. Our data indicate that HSV-1 glycoprotein K (gK) binds to signal peptide peptidase (SPP) and UL20, while UL20 binds to Golgi-specific DHHC zinc finger protein (GODZ). These interactions are regulating gK expression at the cell surface of HSV infected cells. We will use several approaches to determine if blocking these interactions reduce virus replication in the eye and hence, the occurrence of eye disease. Our studies are expected to provide a novel therapeutic strategy to control vision loss from HSV-1 infection.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY013615-15
Application #
9663938
Study Section
Diseases and Pathophysiology of the Visual System Study Section (DPVS)
Program Officer
Mckie, George Ann
Project Start
2001-07-01
Project End
2021-03-31
Budget Start
2019-04-01
Budget End
2021-03-31
Support Year
15
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Cedars-Sinai Medical Center
Department
Type
DUNS #
075307785
City
Los Angeles
State
CA
Country
United States
Zip Code
90048
Jaggi, Ujjaldeep; Wang, Shaohui; Tormanen, Kati et al. (2018) Role of Herpes Simplex Virus Type 1 (HSV-1) Glycoprotein K (gK) Pathogenic CD8+ T Cells in Exacerbation of Eye Disease. Front Immunol 9:2895
Wang, Shaohui; Ljubimov, Alexander V; Jin, Ling et al. (2018) Herpes Simplex Virus 1 Latency and the Kinetics of Reactivation Are Regulated by a Complex Network of Interactions between the Herpesvirus Entry Mediator, Its Ligands (gD, BTLA, LIGHT, and CD160), and the Latency-Associated Transcript. J Virol 92:
Wang, Shaohui; Mott, Kevin R; Wawrowsky, Kolja et al. (2017) Binding of Herpes Simplex Virus 1 UL20 to GODZ (DHHC3) Affects Its Palmitoylation and Is Essential for Infectivity and Proper Targeting and Localization of UL20 and Glycoprotein K. J Virol 91:
Matundan, Harry H; Mott, Kevin R; Allen, Sariah J et al. (2016) Interrelationship of Primary Virus Replication, Level of Latency, and Time to Reactivation in the Trigeminal Ganglia of Latently Infected Mice. J Virol 90:9533-42
Mott, Kevin R; Gate, David; Matundan, Harry H et al. (2016) CD8+ T Cells Play a Bystander Role in Mice Latently Infected with Herpes Simplex Virus 1. J Virol 90:5059-5067
Matundan, Harry H; Mott, Kevin R; Akhtar, Aslam Abbasi et al. (2015) Mutations within the pathogenic region of herpes simplex virus 1 gK signal sequences alter cell surface expression and neurovirulence. J Virol 89:2530-42
Mott, Kevin R; Maazi, Hadi; Allen, Sariah J et al. (2015) Batf3 deficiency is not critical for the generation of CD8?? dendritic cells. Immunobiology 220:518-24
Mott, Kevin R; Allen, Sariah J; Zandian, Mandana et al. (2014) Coregulatory interactions among CD8? dendritic cells, the latency-associated transcript, and programmed death 1 contribute to higher levels of herpes simplex virus 1 latency. J Virol 88:6599-610
Allen, Sariah J; Mott, Kevin R; Ghiasi, Homayon (2014) Inhibitors of signal peptide peptidase (SPP) affect HSV-1 infectivity in vitro and in vivo. Exp Eye Res 123:8-15
Dumitrascu, O M; Mott, K R; Ghiasi, H (2014) A comparative study of experimental mouse models of central nervous system demyelination. Gene Ther 21:599-608

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