Purchase this article with an account.
M.L. Goodkin, S. Epstein, P.A. Asbell, J.A. Blaho; HSV–1 Molecularly Modulates Apoptosis in Infected Rabbit Corneal Epithelial Cell Cultures . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3039.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Herpes simplex virus 1 (HSV–1) infections of human cornea range in severity from uncomplicated episodes that readily resolve to severe, recurring disease that invades the stroma, having a devastating permanent effect on vision. Recent published data implicate an apoptotic component to stromal HSV–1 infection. We previously reported that HSV–1 infection induces, then blocks, apoptosis of epithelial cells, and this block requires infected cell proteins (icp) synthesized between 3 and 6 hours post infection (hpi). This inhibition of apoptosis is in part dependent upon the activation of inducible nuclear transcription factor kappaB (NF–ΚB), a key regulator of immunity, growth, differentiation, and fate of mammalian cells. The purpose of this study was to determine the nature of HSV–1–dependent apoptosis in the corneal epithelium.
Infection of rabbit SIRC cells was used as a model. Apoptotic activities in these cells were compared with that of infected human HEp–2 epithelial cells.
SIRC cells were sensitive to apoptotic cell death induced by environmental treatment with tumor necrosis factor (TNF) plus cycloheximide (CHX). Wild type HSV–1 infection did not induce apoptosis in these cells. However, these infected cells produced detectable levels of cleaved poly(ADP–ribose) polymerase (PARP). Inhibition of SIRC cell protein synthesis with CHX during HSV–1 infection led to a reduction in the amount of PARP cleavage. Consistent with previous results in HEp–2 cells, HSV–1 stimulated the degradation of regulatory IΚB protein in SIRC cells, resulting in nuclear translocation of NF–ΚB. This phenomenon was dependent on icp synthesis.
While PARP cleavage defines cell death in most other cell types, its processing in SIRC cells was a reproducible characteristic of HSV–1 infection. This is the first report of such an effect and it suggests that in corneal cells, activation of apoptotic pathways may be required for productive viral replication. Thus, efficient replication of HSV–1 in the corneal milieu proceeds via a different mechanism than it does in skin. However, it appears that HSV–1 likely inhibits apoptosis via NF–ΚB in both cell systems.
This PDF is available to Subscribers Only