HSV-1 infection suppresses TGF-beta1 and SMAD3 expression in human corneal epithelial cells.

PURPOSE: The present study was undertaken to investigate whether transforming growth factor-beta (TGF-beta) isoforms (TGF-beta1, TGF-beta2, and TGF-beta3) and SMADs (SMAD2 and SMAD3) are involved in herpes simplex virus type 1 (HSV-1) corneal infection. METHODS: Human corneal epithelial cells (HCE) were infected with HSV-1 at a multiplicity of infection of 5. Cell morphological changes were observed under phase-contrast microscopy. Levels of mRNA for TGF-beta isoforms 1, 2, and 3 as well as for SMAD2 and SMAD3 were measured by reverse transcription polymerase chain reaction (RT-PCR) at 0 h, 4 h, 8 h, 12 h, and 24 h after infection. Protein expression of TGF-beta1, TGF-beta2, SMAD3, and phospho-SMAD3 were analyzed by indirect immunofluorescence at 0 h, 12 h, and 24 h post-infection (p.i.) in HCE cells. Protein expression of TGF-beta1 was also evaluated by ELISA. RESULTS: Following HSV-1 infection, a cytopathic effect in HCE cells was observed at 8 h p.i. and became significant at 24 h p.i. Compared with normal cells, the mRNA levels of TGF-beta1 in HSV-1 infected HCE cells decreased significantly at 8 h, 12 h, and 24 h p.i. (p<0.01), and the expression of SMAD3 was also dramatically decreased 12 h and 24 h p.i. (p<0.01). No noticeable changes were found as a result of infection with respect to levels of TGF-beta2, TGF-beta3, and SMAD2 in HCE cells. Protein expression of TGF-beta1, SMAD3, and phospho-SMAD3 decreased in infected cells at 12 h and 24 h p.i. compared with normal cells, but TGF-beta2 had no change. CONCLUSIONS: TGF-beta1 and SMAD3 may be involved in the pathology of corneal diseases associated with HSV-1 infection.

[Effects of HSV-1 on the growth of human retinal pigment epithelial cells].

PURPOSE: The present study was aimed to investigate whether herpes simplex virus type 1 (HSV-1) could infect human retinal pigment epithelial (RPE) cells in vitro and the effects of HSV-1 on the growth of human RPE cells. METHODS: RPE cell line D407 was infected with HSV-1 F strain at a multiplicity of infection of 5. The susceptibility to HSV-1 was assessed by the detection of viral DNA using the polymerase chain reaction (PCR), and viral antigen using immunofluorescence staining. At indicated times, contrast-phase microscope was used to record the morphological changes of HSV-1 infection of RPE cells. Cell proliferation was measured by MTT assay. Cell apoptosis and cell cycle were detected by flow cytometry. RESULTS: HSV-1 infected RPE cells successfully in vitro. The contrast-phase microscope revealed that cytopathic effects (CPE) were first observed at 8 h post-infection. The infected cells became slender and shrinking. At 24 h post-infection, nearly all the cells displayed CPE changes. Occasionally multinucleated giant cells were found. At 48 h, the infected cells became round, some even detached from the culture flask. Cell proliferation were dramatically inhibited by HSV-1 at 24 h and 48 h post-infection, and the inhibition ratio were (16.37 +/- 3.28)% and (47. 91 +/- 6.39)% respectively. Furthermore, HSV-1 could perturb the cell cycle in the infected cells, and had no effect on cell apoptosis. CONCLUSIONS: Our data suggested that RPE cells are susceptible to HSV-1. HSV-1 can inhibit cell proliferation and perturb the cell cycle in the infected cells.