Background Cornea epithelial cells play eady and crucial roles in the initiation of ocular surface responses to pathogens. Participation of toll-like receptor （TLR） 2 and TLR4, which are major forms of fungi recepto...Background Cornea epithelial cells play eady and crucial roles in the initiation of ocular surface responses to pathogens. Participation of toll-like receptor （TLR） 2 and TLR4, which are major forms of fungi receptors, may be involved in Aspergillus fumigatus induced immune responses. The objective of the present study was to examine whether inactive Aspergillus fumigatus conidia induce NF-KB activation and production of proinflammaory cytokines, and whether the expression of TLR2 and TLR4 were amplified by conidia in cultured immortalized human corneal epithelial cells （THCEs）. This may contribute to our knowledge of the mechanism by which the host cornea can successfully defend against invasive fungi. Methods Aspergillus fumigatus conidia were used to challenge THCE cells. THCE cells were harvested after 0.5, 1, 2 or 4 hours incubation. Real-time quantitative PCR was performed to determine the expression of TLR2, TLR4, TNF-a and IL-8. Western blotting was performed to determine the expression of NF-KB. Enzyme-linked immunosorbent assay （ELISA） was performed to determine the expression of TNF-a and IL-8. And the release of TNF-a and IL-8 in the cell supematant were also assessed by ELISA with or without pretreatment with TLR2 and TLR4 neutralizing antibodies. Results Aspergillus fumigatus conidia elicited the expression of TLR2, TLR4, TNF-a and IL-8 mRNA in THCEs. Exposure of THCE cells to Aspergillus fumigatus conidia resulted in NF-KB activation, which increased at 30 minutes （increased from 11.35±2.74 in the controls to 19.12±3.48, p〈0.05） and thereafter increased steadily up to 4 hours after challenge （P 〈0.01）. Concomitant with NF-KB activation, secretion of TNF-α and IL-8 in conidia-challenged cells was increased in a time-dependent manner. Incubation of THCE cells with TLR2 antibody or TLR4 antibody before conidia challenge resulted in inhibition of conidia-induced TNF-α and IL-8 secretion （P 〈0.05）, TLR2 antibody and TLR4 antibody together significantly increased inhibition of the conidia-induced secretion of TNF-α and I L-8 from THCE cells （P 〈0.01）. Conclusion Aspergillus fumigatus conidia stimulates THCEs inflammatory response through a pathway dependent on TLR2 and TLR4 signaling.展开更多
基金This study was supported by a grant from the National Natural Science Foundation of China （No. 30571997）.
文摘Background Cornea epithelial cells play eady and crucial roles in the initiation of ocular surface responses to pathogens. Participation of toll-like receptor （TLR） 2 and TLR4, which are major forms of fungi receptors, may be involved in Aspergillus fumigatus induced immune responses. The objective of the present study was to examine whether inactive Aspergillus fumigatus conidia induce NF-KB activation and production of proinflammaory cytokines, and whether the expression of TLR2 and TLR4 were amplified by conidia in cultured immortalized human corneal epithelial cells （THCEs）. This may contribute to our knowledge of the mechanism by which the host cornea can successfully defend against invasive fungi. Methods Aspergillus fumigatus conidia were used to challenge THCE cells. THCE cells were harvested after 0.5, 1, 2 or 4 hours incubation. Real-time quantitative PCR was performed to determine the expression of TLR2, TLR4, TNF-a and IL-8. Western blotting was performed to determine the expression of NF-KB. Enzyme-linked immunosorbent assay （ELISA） was performed to determine the expression of TNF-a and IL-8. And the release of TNF-a and IL-8 in the cell supematant were also assessed by ELISA with or without pretreatment with TLR2 and TLR4 neutralizing antibodies. Results Aspergillus fumigatus conidia elicited the expression of TLR2, TLR4, TNF-a and IL-8 mRNA in THCEs. Exposure of THCE cells to Aspergillus fumigatus conidia resulted in NF-KB activation, which increased at 30 minutes （increased from 11.35±2.74 in the controls to 19.12±3.48, p〈0.05） and thereafter increased steadily up to 4 hours after challenge （P 〈0.01）. Concomitant with NF-KB activation, secretion of TNF-α and IL-8 in conidia-challenged cells was increased in a time-dependent manner. Incubation of THCE cells with TLR2 antibody or TLR4 antibody before conidia challenge resulted in inhibition of conidia-induced TNF-α and IL-8 secretion （P 〈0.05）, TLR2 antibody and TLR4 antibody together significantly increased inhibition of the conidia-induced secretion of TNF-α and I L-8 from THCE cells （P 〈0.01）. Conclusion Aspergillus fumigatus conidia stimulates THCEs inflammatory response through a pathway dependent on TLR2 and TLR4 signaling.
