Co-regulation of Dectin-1 and TLR2 in inflammatory response of human corneal epithelial cells induced by Aspergillus fumigates.

AIM

To investigate the co-regulation of dendritic cell-associated C-type lectin-1 (Dectin-1), Toll-like receptor 2 (TLR2), and relative chemotactic factors in the Telomease-immortalized human corneal epithelial (THCE) cells after exposure to Aspergillus fumigatus (Af) hyphae.

METHODS

The normal THCE cells were investigated as control. After cultured in vitro with Af hyphae, with or without laminarin and anti-TLR2 antibody for 4, 8, 16 and 24h, THCE cells were harvested. The expression of Dectin-1, TLR2, CXCL1 and CXCL8 mRNA were measured by real-time quantitative polymerase chain reaction at the stimulation of 4, 8 and 16h separately. The protein expression of Dectin-1 and TLR2 were analyzed at 8, 16, and 24h by Western blot.

RESULTS

The mRNA expression of CXCL1 and CXCL8 increased in THCE cells after stimulated by Af hyphae. The stimulatory effects on these inflammatory chemokines were shown in a dose-dependent manner and reached the peak at 8h. Af hyphae significantly stimulated the production of Dectin-1 and TLR2 in THCE cells at both mRNA and protein levels. The protein of Dectin-1 and TLR2 gradually increased till 16h. While pretreated with laminarin (a Dectin-1 inhibitor), the expression of TLR2, CXCL1 and CXCL8 all decreased dramatically at the peak point. Interestingly, when pretreated with TLR2 neutralizing antibody, the expression of Dectin-1, CXCL1 and CXCL8 also decreased dramatically at the peak point.

CONCLUSION

These findings suggest that Dectin-1 and TLR2 co-regulated with each other after treated with inactive Af hyphae in the THCE cells, and they contribute together to the inflammatory responses by induction of chemokines CXCL1 and CXCL8.