Toll-like receptors (TLRs) expression and function in response toinactivate hyphae of Fusarium solani in immortalized human cornealepithelial cells

[摘要] Purpose: To evaluate the role of toll-like receptors (TLRs) in hostresponses to Fusarium solani by the use of cultured immortalizedhuman corneal epithelial cells (HCEC) and to determine whether inactivehyphal fragments can induce an antifungal response in these cells.Methods: Cultured HCEC cells were stimulated with inactive hyphalfragments from Fusarium solani, and the effect on expression of TLRswas determined by real-time polymerase chain reaction (PCR),immunofluorescence, and western blot analysis. Cells were alsococultured with hyphal fragment and hydrocortisone to determine whetherhydrocortisone modulates the transcription of TLRs. The release ofinterleukin-6 (IL-6) and IL-8 was also measured using enzyme-linkedimmunosorbent assays (ELISA) in the presence and absence of specificblocking antibodies to TLR2 and TLR4.Results: Incubation of HCECs with inactive hyphal fragmentsupregulated the expression of TLR2, 3, 4, and 6 mRNAs and increased therelease of IL-6 and IL-8. Immunofluorescence staining and western blotanalysis confirmed that expression of TLR2 and TLR4 was upregulated inresponse to hyphal fragments. This upregulation was further enhanced bycotreatment with hydrocortisone. Results from ELISA assays showed thatthe concentration of IL-6 was increased, and the concentration of IL-8was decreased in supernatants of HCECs after treatment with bothhydrocortisone and hyphal fragments. The release of IL-6 and IL-8 wasalso inhibited by incubation with anti-TLR2 and anti-TLR4 monoclonalantibodies.Conclusions: HCECs are involved in the cornea immune response tofungal infections. TLR2 and TLR4 may play a crucial signaling role inresponse to Fusarium hyphae in HCECs. Glucocorticoids such ashydrocortisone can enhance the expression of the TLRs on the epitheliumand thus may enhance the resistance to fungal infections in the cornea.These findings may provide crucial information for understanding theimmune mechanisms of fungal keratitis and promote the design of newimmune therapeutical approaches to fungal keratitis.

[学科分类] 生物化学/生物物理