Granulocyte Macrophage Colony-Stimulating Factor Expression in Human Herpetic Stromal Keratitis: Implications for the Role of Neutrophils in HSK

• Published in: Investigative ophthalmology & visual science Vol. 48; no. 1; pp. 277 - 284
• Main Authors: Duan, Rui, Remeijer, Lies, van Dun, Jessica M, Osterhaus, Albert D. M. E, Verjans, Georges M. G. M
• Format: Journal Article
• Language: English
• Published: Rockville, MD ARVO 01.01.2007; Association for Research in Vision and Ophtalmology
• Subjects: Antibody-Dependent Cell Cytotoxicity; Biological and medical sciences; Cells, Cultured; Corneal Stroma - cytology; Corneal Stroma - metabolism; Corneal Stroma - virology; Diseases of cornea, anterior segment and sclera; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Epithelium, Corneal - drug effects; Epithelium, Corneal - metabolism; Eye and associated structures. Visual pathways and centers. Vision; Fibroblasts - drug effects; Fibroblasts - metabolism; Fundamental and applied biological sciences. Psychology; Granulocyte-Macrophage Colony-Stimulating Factor - genetics; Granulocyte-Macrophage Colony-Stimulating Factor - metabolism; Herpesvirus 1, Human - physiology; Human viral diseases; Humans; Immunoenzyme Techniques; Infectious diseases; Interferon-gamma - pharmacology; Interleukin-1beta - pharmacology; Interleukin-8 - metabolism; Keratitis, Herpetic - metabolism; Medical sciences; Neutrophil Activation; Neutrophils - physiology; Ophthalmology; Reverse Transcriptase Polymerase Chain Reaction; RNA - isolation & purification; RNA, Messenger - metabolism; Tumor Necrosis Factor-alpha - pharmacology; Vertebrates: nervous system and sense organs; Viral diseases; Viral diseases with cutaneous or mucosal lesions and viral diseases of the eye; Infection; Human; Eye disease; Keratitis; Viral disease; Herpes; Stroma; Keratopathy; Neutrophil; Ophthalmology; Anterior segment disease; Granulocyte macrophage colony stimulating factor
• ISSN: 0146-0404; 1552-5783; 1552-5783
• DOI: 10.1167/iovs.06-0053

Granulocyte macrophage colony-stimulating factor (GM-CSF) is thought to play a key role in chronic inflammatory diseases by governing the survival and function of infiltrating neutrophils. The objective of this study was to determine the putative role of GM-CSF in the pathogenesis of human herpetic stromal keratitis (HSK). Primary human corneal fibroblast (HCF) cultures and a telomerase-immortalized human corneal epithelial (HCE) cell line representative of native HCE were stimulated with the known HSK-inducing cytokines interferon (IFN)-gamma, interleukin (IL)-1beta, and tumor necrosis factor (TNF)-alpha. Alternatively, the T-cell cytokine IL-17 was added solely or simultaneously. Human neutrophils were incubated with conditioned medium (CM) of the HCF and HCE stimulated with the aforementioned cytokines, or recombinant GM-CSF, and their viability or activation status was determined by flow cytometry. GM-CSF and IL-8 secretion levels in the CM were determined by ELISA. The antibody-dependent cellular cytotoxicity (ADCC) of neutrophils toward herpes simplex virus (HSV)-infected HCFs was determined by flow cytometry. The expression of GM-CSF was determined in HSK and control corneal buttons by real-time RT-PCR and immunohistology. Compared with IFN-gamma, CM of either cell type stimulated with IL-1beta, or in the case of HCE cells, stimulated with TNF-alpha or IL-17, delayed neutrophil apoptosis significantly. Only in HCFs did IL-17 exhibit a synergistic effect with TNF-alpha. The antiapoptotic activity was attributable in part to the GM-CSF secreted by the activated HCFs and HCE cells. GM-CSF stimulation of neutrophils induced their activation and the secretion of IL-8. GM-CSF did not increase significantly the ADCC reaction of neutrophils toward HSV-infected HCFs. Finally, GM-CSF was expressed in corneas of the patients with HSK but not in control subjects. The data suggest that GM-CSF, expressed by cornea-resident cells such as HCFs and HCE cells, may play a role in the immunopathogenesis of HSK by prolonging the survival and modulating the effector function of corneal infiltrating neutrophils.