Abstract
Purpose :
The focus of this study was to characterize CXCR4-expressing cells in uninfected and herpes simplex virus-1 (HSV-1) infected corneas.
Methods :
The corneas of C57BL/6J mice were infected with HSV-1 McKrae. The RT-qPCR assay detected CXCR4 and CXCL12 transcripts in the corneas from uninfected and HSV-1-infected mice. Immunofluorescence staining for CXCR4 and CXCL12 protein was performed in the frozen sections of herpes stromal keratitis (HSK) corneas. Flow cytometry assay characterized the CXCR4-expressing cells in uninfected and HSV-1-infected corneas.
Results :
Our results showed significantly higher CXCR4 and CXCL12 transcripts in HSK corneas than in uninfected corneas. Furthermore, the corneal stroma (CS), compared to corneal epithelium (CE) from HSV-1 infected mice exhibited a significantly increased level of CXCL12 at 9-day post-infection. Immunofluorescence staining showed CXCR4 and CXCL12 protein localization in the newly formed blood vessels in the HSK cornea. Flow cytometry data showed CXCR4 expressing cells in the separated epithelium and stroma from uninfected corneas. In the uninfected corneal stroma, CD11b+F4/80+ macrophages are the predominant CXCR4-expressing cells. In contrast, most CXCR4 expressing cells in the uninfected corneal epithelium were CD207 (langerin)+, CD11c+, and expressed MHC class II molecule, documenting the Langerhans cells (LCs) phenotype. After corneal HSV-1 infection, the LCs proliferation increased their numbers in the corneal epithelium at 4 days post-infection (p.i.). However, by 9-day p.i., the LCs numbers declined to the counts observed in naïve corneal epithelium. Interestingly, a significant increase in the number of langerin+ cells is seen in the corneal stroma of infected eyes from 4-day to 9-day p.i., suggesting a possible migration of langerin+ cells from the CE to CS of infected mice. Our results also showed neutrophils and vascular endothelial cells as the prominent CXCR4-expressing cell types in the corneal stroma of HSK corneas.
Conclusions :
Together, our data demonstrate the expression of CXCR4 on resident immune cells in the uninfected cornea and on infiltrating neutrophils and newly formed blood vessels in the HSK cornea. The current experiments are determining the outcome of blocking CXCR-CXCL12 interaction on stromal hemangiogenesis in HSK corneas.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.