The incidence of cytomegalovirus retinitis has decreased in human immunodeficiency virus (HIV)-infected patients concomitant with the widespread use of highly actively antiretroviral therapy (HAART). However despite this decrease, there are HIV infected patients who are still at risk for CMV retinitis because they do not/cannot follow the prescribed therapeutic regimen of anti-HIV drugs. Therefore, an increased understanding of the mechanisms underlying the pathogenesis of CMV has the potential for translation into preventative or ameliorative treatments in patients who are at still at risk for developing CMV retinitis. In this application, a combination of in vitro and in vivo studies using mice, mouse tissues, and cultured cells are proposed to decipher the mechanism of several features of murine cytomegalovirus (MCMV) retinitis including the process of sequential infection from the outer retina (following inoculation of virus via the supraciliary route which allows the virus to gain access to the subretinal space) to the inner retina and the observation from both mouse and from human studies that cytomegalovirus infected cells usually do not undergo apoptosis. The studies proposed in this application will take advantage of recent advances in understanding apoptotic pathways and in how cytomegalovirus may interact with the host to induce retinal damage. The first specific aim will determine how infection of RPE cells induces apoptosis in the overlying retina.
This aim will test the hypothesis that production of iNOS and NO by infected RPE cells begins the cascade of retinal infection and damage during MCMV retinitis.
This aim will also allow us to determine the contribution of TNF-1 during initial infection of the RPE. The second Specific Aim will determine to what extent TNF-1 and NO cause apoptosis of uninfected retinal cells via caspase-dependent and caspase-independent pathways, respectively.
This aim will test the hypothesis that caspase-dependent as well as caspase-independent apoptosis contributes to retinal pathology during MCMV retinitis. The third Specific Aim will determine why MCMV infected retinal cells do not undergo apoptosis.
This aim will test the hypothesis that MCMV immediate early protein 3 (IE-3) plays an important role in protecting infected cells from apoptosis by upregulating the cellular FLICE-inhibitory protein (c-FLIP). The results of these studies will provide new information about the mechanisms of MCMV infection of the retina which may be applicable to new therapeutic approaches to prevent cytomegalovirus infection of the retina or to reduce retinal damage in human patients.

Public Health Relevance

The incidence of cytomegalovirus retinitis has decreased in human immunodeficiency virus (HIV)-infected patients concomitant with the widespread use of highly actively antiretroviral therapy (HAART). Despite this decrease however, there are HIV infected patients who are still at risk for cytomegalovirus retinitis because they do not/cannot follow the prescribed therapeutic regimen of anti-HIV drugs or their virus becomes drug resistant. Increased understanding of the mechanisms underlying the pathogenesis of cytomegalovirus infections has the potential for translation into preventative or ameliorative treatments in patients who are at still at risk for development of CMV retinitis. Results of the proposed studies will provide new information about the mechanisms of cytomegalovirus infection of the retina which may be applicable to new therapeutic approaches to prevent retinal infection and/or to reduce retinal damage.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY009169-18
Application #
7898782
Study Section
Anterior Eye Disease Study Section (AED)
Program Officer
Shen, Grace L
Project Start
1994-09-30
Project End
2012-07-31
Budget Start
2010-08-01
Budget End
2011-07-31
Support Year
18
Fiscal Year
2010
Total Cost
$327,443
Indirect Cost
Name
Georgia Regents University
Department
Biology
Type
Schools of Medicine
DUNS #
966668691
City
Augusta
State
GA
Country
United States
Zip Code
30912
Mo, Juan; Marshall, Brendan; Covar, Jason et al. (2014) Role of Bax in death of uninfected retinal cells during murine cytomegalovirus retinitis. Invest Ophthalmol Vis Sci 55:7137-46
Marshall, Brendan; Mo, Juan; Covar, Jason et al. (2014) Decrease of murine cytomegalovirus-induced retinitis by intravenous delivery of immediate early protein-3-specific siRNA. Invest Ophthalmol Vis Sci 55:4151-7
Mo, Juan; Zhang, Ming; Marshall, Brendan et al. (2014) Interplay of autophagy and apoptosis during murine cytomegalovirus infection of RPE cells. Mol Vis 20:1161-73
Zhang, Ming; Covar, Jason; Marshall, Brendan et al. (2011) Lack of TNF-alpha promotes caspase-3-independent apoptosis during murine cytomegalovirus retinitis. Invest Ophthalmol Vis Sci 52:1800-8
Zhang, Ming; Marshall, Brendan; Atherton, Sally S (2008) Murine cytomegalovirus infection and apoptosis in organotypic retinal cultures. Invest Ophthalmol Vis Sci 49:295-303
Zhou, Jun; Zhang, Ming; Atherton, Sally S (2007) Tumor necrosis factor-alpha-induced apoptosis in murine cytomegalovirus retinitis. Invest Ophthalmol Vis Sci 48:1691-700
Zhang, Ming; Zhou, Jun; Marshall, Brendan et al. (2007) Lack of iNOS facilitates MCMV spread in the retina. Invest Ophthalmol Vis Sci 48:285-92
Zhang, Ming; Xin, Hua; Duan, Yanping et al. (2005) Ocular reactivation of MCMV after immunosuppression of latently infected BALB/c mice. Invest Ophthalmol Vis Sci 46:252-8
Zhang, Ming; Xin, Hua; Atherton, Sally S (2005) Murine cytomegalovirus (MCMV) spreads to and replicates in the retina after endotoxin-induced disruption of the blood-retinal barrier of immunosuppressed BALB/c mice. J Neurovirol 11:365-75
Bigger, J E; Tanigawa, M; Zhang, M et al. (2000) Murine cytomegalovirus infection causes apoptosis of uninfected retinal cells. Invest Ophthalmol Vis Sci 41:2248-54

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