Indoleamine 2,3-dioxygenase 1 in corneal endothelial cells limits herpes simplex virus type 1-induced acquired immune response.

BACKGROUND: Corneal endothelial cells are known to be targets of herpes simplex virus type 1 (HSV-1) infection; however, the pathogenesis of HSV infections of the endothelial cells has not been definitively determined. The purpose of this study was to examine an unrecognised strategy of corneal endothelial cells to protect themselves from HSV-1 infection. METHODS: Immortalised human corneal endothelial cells (HCEn) were infected with HSV-1. Based on the global transcriptional profile, the expression of indoleamine 2,3-dioxygenase 1 (IDO1) was determined using real-time PCR and western blots. To examine whether IDO1 has any antiviral role, we tested whether viral replication was affected by blocking the activity of IDO1. The immune modulatory role of IDO1 was analysed to determine whether IDO1 might contribute to modulating the recall responses of HSV-1-sensitised CD4(+) T cells. RESULTS: IDO1 was strongly expressed in HCEn cells after HSV-1 infection. IDO1 blockade did not significantly restrict viral transcription or replication, arguing against a previously recognised antiviral role for IDO1. When HCEn cells were examined for antigen-presenting function, HSV-1-primed HCEn cells stimulated the proliferation of allogeneic CD4(+) T cells and interleukin 10 (IL-10) secretion. When the recall response to HSV-1 was measured by the mixed lymphocyte reaction, the HCEn-stimulated CD4(+) T cells modulated and limited the recall response. When IDO1 was silenced in HCEn cells, the HCEn-mediated immune modulatory activity and regulatory T-cell activation were reduced. Overexpression of IDO1 promoted immune modulatory activity, which was partly conveyed by IL-10. CONCLUSIONS: IDO1 induced by HSV-1 infection limits and dampens excessive acquired immune responses in corneal endothelial cells.

Associations of inflammatory cytokines with choroidal neovascularization in highly myopic eyes.

PURPOSE: To determine the relationships between the levels of intraocular inflammatory cytokines and the clinical characteristics of myopic choroidal neovascularization (mCNV) in eyes with myopic maculopathy. METHODS: One hundred eyes of 100 cases, including 51 mCNV eyes, 14 highly myopic eyes without choroidal neovascularization, and 35 normal subjects, were studied. The intraocular levels of choroidal neovascularization-related cytokines, like vascular endothelial growth factor, MCP-1, IL-8, IL-10, and IL-23, were determined. RESULTS: The levels of vascular endothelial growth factor and IL-8 were significantly higher in eyes with mCNV than in high myopia eyes without mCNV with significant odds ratio of 2.00 and 2.25 per quartile, respectively (P < 0.05). When myopic lesions of patients with mCNV were classified into 3 categories based on the severity, IL-8 and MCP-1 were significantly elevated depending on the presence of maculopathy (P < 0.05). Vascular endothelial growth factor was significantly elevated in eyes of Category 2. An advancement of the maculopathy category was significantly associated with the need for multiple treatment of intravitreal bevacizumab (P < 0.05). In 12 eyes that required multiple intravitreal bevacizumab, the MCP-1 level was significantly elevated. CONCLUSION: The significant associations of mCNV in highly myopic eyes with elevated levels of vascular endothelial growth factor or inflammatory cytokines and maculopathy lesions strongly suggest an involvement of inflammation in the etiology of mCNVs.

Efficacy of herpes virus helicase-primase inhibitor, ASP2151, for treating herpes simplex keratitis in mouse model.

AIMS: To determine the efficacy of a new helicase-primase inhibitor, ASP2151, for treating herpetic keratitis. METHODS: Murine corneas were infected with herpes simplex virus type 1 (HSV-1). ASP2151 was administered orally or topically, and the severity of epithelial dendritic keratitis was determined. The effectiveness of ASP2151 was compared with that of acyclovir and valacyclovir. The reduction of the amount of HSV in tears, enucleated eyes and trigeminal ganglia was determined by real-time PCR or plaque assay. RESULTS: Orally administered ASP2151 reduced the epithelial keratitis score significantly more than that of the vehicle-treated group (p<0.01). It also lowered the HSV-DNA levels in the tears significantly more than that by valacyclovir (p<0.01). ASP2151 ointment resulted in the same reduction of the keratitis score as acyclovir ointment, and lowered the HSV DNA in tears more than acyclovir ointment. Topical instillation of ASP2151 improved the herpetic dendritic keratitis score significantly and reduced the titre of HSV DNA in the tears in a dose-responsive way. CONCLUSIONS: ASP2151 had significantly better anti-HSV activity against herpes simplex keratitis than valacyclovir and acyclovir after systemic or topical use. These findings indicate that ASP2151 should be considered as an alternative treatment for herpes simplex keratitis.

Roles played by toll-like receptor-9 in corneal endothelial cells after herpes simplex virus type 1 infection.

PURPOSE: To determine the roles played by toll-like receptor 9 (TLR9) in cultured human corneal endothelial (HCEn) cells after herpes simplex virus type 1 (HSV-1) infection and to characterize the TLR9-mediated antiviral responses. METHOD: Immortalized HCEn cells were examined for TLR expression. The upregulation of inflammatory cytokines after HSV-1 infection was determined by real-time RT-PCR or protein array analyses. The TLR9-mediated HSV-1 replication was determined by real-time PCR and plaque assay. To determine whether there was an activation of the signal transduction pathway, HCEn cells that were transfected with pathway-focused transcription factor reporters were examined for promoter activity. RESULTS: TLR9 was abundantly expressed intracellularly in HCEn cells. The CpG oligonucleotide, a TLR9 ligand, stimulated the NF-κB activity in HCEn cells. HSV-1 infection also stimulated NF-κB and induced NF-κB -related inflammatory cytokines, including RANTES, IP-10, MCP-2, MIF, MCP-4, MDC, MIP-3α, IL-5, TARC, MCP-1, and IL-6. The induction of these cytokines was significantly reduced by blocking the activity of TLR9. In addition, viral replication in HCEn cells was significantly reduced by the inhibition of TLR9, but was preserved by a concomitant activation of the NF-κB cascade. Of the different HSV-1-induced inflammatory cascade-related transcription factors, TLR9 was found to activate NF-κB, cyclic AMP response element (CRE), and the CCAAT-enhancer-binding proteins (C/EBP) the most. CONCLUSIONS: Corneal endothelial cells transcriptionally initiate inflammatory programs in response to HSV-1 infection related to NF-κB, CRE, and C/EBP and express arrays of inflammatory cytokine induction by TLR9. On the other hand, HSV-1 exploits TLR9-mediated NF-κB activation for its own replication.