Varicella zoster virus (VZV) causes varicella during primary infection, persists in sensory ganglia and may reactivate from latency to cause zoster. VZV pathogenesis depends upon its tropisms for T cells, skin and sensory ganglia. VZV vaccines to prevent varicella and to reduce zoster morbidity in the elderly are very effective. However, VZV control could be improved with a 2nd generation recombinant vaccine that has attenuated replication in skin, but limited infectivity for T cells and ganglia. VZV infection of sensory ganglia ensures its survival in the human population through reactivations from latency that result in zoster. We have developed a model for studying VZV neuropathogenesis by making xenografts of human dorsal root ganglia (DRG) in mice with severe combined immunodeficiency (SCID). Our analyses of VZV tegument/regulatory proteins will be extended to examine their functions in VZV neurotropism. We will focus on IE63, an important immediate early regulatory protein encoded by ORF63, and the ORF66 kinase protein using VZV recombinants that have targeted mutations in these genes. The SCIDhu DRG model also offers unique opportunities to investigate how cell transactivators that modulate viral gene promoters may control VZV neurotropism and to identify what perturbations of persistently infected neurons may trigger of VZV reactivation. The roles of IE63 and ORF66 at early and late stages of VZV infection of ganglia will be examined in SCIDhu DRG. Experiments will address four general hypotheses: 1) initial VZV replication is required for, or influences the level of persistent VZV DNA copies in neurons;2) VZ virions must be made and released efficiently;3) VZV proteins that inhibit neural cell apoptosis facilitate persistence;4) VZV infection of DRG reflects an equilibrium with innate cellular responses, mediated by interferons (IFN), which optimizes persistence. VZV gene promoters, like those of all herpesviruses, have elements that are recognized by ubiquitous host cell regulatory proteins. Our hypothesis is that cellular proteins regulate transcription from the critical ORF63 promoter during initial infection and are needed for the transition to latency in sensory neurons. Experiments to understand what cellular stressors may induce VZV reactivation from persistently infected DRG will examine heat, chemical agents, histone deacetylase inhibitors, interference with nerve growth factor signaling and other triggers known to enhance herpes simplex virus reactivation. The work proposed for Yr. 1 and Yr. 2 (see Specific Aims) is expected to yield new information about the molecular mechanisms of VZV neuropathogenesis in differentiated peripheral neurons and satellite cells within human sensory ganglia and to identify options for designing a 2nd generation VZV vaccine with genetic changes that have been proved to reduce virulence in the SCIDhu DRG model in vivo.

Public Health Relevance

Chickenpox and herpes zoster (shingles) are caused by varicella-zoster virus (VZV). These infections remain an important public health problem in the United States. The licensed VZV vaccines induce protection in most children and elderly adults but complications can occur in healthy vaccine recipients and in those who have diseases that impair their immune systems. Our goal is to identify strategies for creating better vaccines to prevent VZV infections in healthy and high risk people.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI053846-09
Application #
8293354
Study Section
Virology - A Study Section (VIRA)
Program Officer
Challberg, Mark D
Project Start
2003-01-01
Project End
2013-06-30
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
9
Fiscal Year
2012
Total Cost
$466,116
Indirect Cost
$150,228
Name
Stanford University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Khalil, Mohamed I; Che, Xibing; Sung, Phillip et al. (2016) Mutational analysis of varicella-zoster virus (VZV) immediate early protein (IE62) subdomains and their importance in viral replication. Virology 492:82-91
Xing, Yi; Oliver, Stefan L; Nguyen, TuongVi et al. (2015) A site of varicella-zoster virus vulnerability identified by structural studies of neutralizing antibodies bound to the glycoprotein complex gHgL. Proc Natl Acad Sci U S A 112:6056-61
Khalil, Mohamed I; Ruyechan, William T; Hay, John et al. (2015) Differential effects of Sp cellular transcription factors on viral promoter activation by varicella-zoster virus (VZV) IE62 protein. Virology 485:47-57
Khalil, Mohamed I; Sommer, Marvin H; Hay, John et al. (2015) Varicella-zoster virus (VZV) origin of DNA replication oriS influences origin-dependent DNA replication and flanking gene transcription. Virology 481:179-86
Sen, Nandini; Mukherjee, Gourab; Arvin, Ann M (2015) Single cell mass cytometry reveals remodeling of human T cell phenotypes by varicella zoster virus. Methods 90:85-94
Sen, Nandini; Mukherjee, Gourab; Sen, Adrish et al. (2014) Single-cell mass cytometry analysis of human tonsil T cell remodeling by varicella zoster virus. Cell Rep 8:633-45
Zerboni, Leigh; Sen, Nandini; Oliver, Stefan L et al. (2014) Molecular mechanisms of varicella zoster virus pathogenesis. Nat Rev Microbiol 12:197-210
Khalil, Mohamed I; Sommer, Marvin; Arvin, Ann et al. (2014) Cellular transcription factor YY1 mediates the varicella-zoster virus (VZV) IE62 transcriptional activation. Virology 449:244-53
Wang, Li; Rajamani, Jaya; Sommer, Marvin et al. (2013) Identification of a hydrophobic domain in varicella-zoster virus ORF61 necessary for ORF61 self-interaction, viral replication, and skin pathogenesis. J Virol 87:4075-9
Khalil, Mohamed I; Sommer, Marvin; Arvin, Ann et al. (2013) Regulation of the varicella-zoster virus ORF3 promoter by cellular and viral factors. Virology 440:171-81

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