[Dermatophagoides farinae induces conjunctival epithelial cell damage to promote neutrophil migration and neutrophil extracellular traps formation].

OBJECTIVE

To investigate the mechanisms underlying allergic conjunctivitis caused by conjunctival epithelial cell damage, neutrophil migration and neutrophil extracellular traps (NETs) formation induced by crude extracts of Dermatophagoides farinae mite (CDM).

METHODS

Human conjunctival epithelial cells were stimulated with 500, 1 000, 2 000, 4 000 ng/mL, and the expression levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and IL-8 were detected using quantitative real-time PCR (qPCR) assay and enzyme-linked immunosorbent assay (ELISA). The culture supernatant of human conjunctival epithelial cells was collected and co-cultured with neutrophils. Neutrophil migration was measured using Transwell migration assay, and the expression of NETs markers myeloperoxidase (MPO) and citrullinated histone H3 (CitH3) was quantified using immunofluorescence staining. Neutrophils were stimulated with phorbol 12-myristate 13-acetate (PMA), and then NETs were collected for treatment of human conjunctival epithelial cells. Cell apoptosis was detected using flow cytometry, and the levels of IL-6, TNF-α, IFN-γ and IL-8 were measured in the cell culture supernatant using ELISA.

RESULTS

Treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL up-regulated IL-6, TNF-α, IFN-γ and IL-8 expression in human conjunctival epithelial cells. Following treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL, the culture supernatant of human conjunctival epithelial cells promoted neutrophil migration and induced increases in the staining intensity of MPO and CitH3. In addition, increased NETs triggered the apoptosis of human conjunctival epithelial cells and IL-6, TNF-α, IFN-γ and IL-8 secretion in the culture supernatant of human conjunctival epithelial cells.

CONCLUSIONS

CDM induces human conjunctival epithelial cell damages, thereby promoting neutrophil migration and NETs formation, while the release of NETs further aggravates human conjunctival epithelial cell damages.