Purpose: Fungal keratitis (FK) is a blinding infection of the corneas and accounts for a significant portion of all keratitis in the world but little is known about the pathogenesis of FK, especially at the level of molecular biology. This study tried to determine the genes that are modulated in the process and thus deserve further investigation for understanding the pathogenesis of FK.
Methods: Agilent Mouse Oligo Microarray was used to compare the gene profiles in control corneas and in corneas challenged with heat-inactivated Aspergillus fumigatus spores. Semiquantitative reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were used to confirm the changes of interested genes.
Results: In the 18,335 genes detected by array, 61 showed an increase of more than one-fold in RNA expression and 48 showed a decrease of over 50%. Among the regulated genes some are known to be related to host defense such as IL3, mannose binding lectin A (MBL-A), and prostaglandin D2 synthase (Psgd) while others like Dopachrome tautomerase (Dct) have never been correlated to ocular or host defense. The other 33 changed genes either have unknown functions or encode hypothetical proteins. The changes in the expression of early growth response 4 (Egr4), Dct, Psgd, MBL-A, and hemoglobin alpha adult chain 1 were confirmed by using RT-PCR. MBL-A expression regulation was further confirmed by using immunohistochemistry in both in vitro and in vivo challenged murine corneas.
Conclusions: MBL-A is among the primary responding genes during the onset of fungal keratitis. Also it was found that the microarray is a useful tool in elucidating the pathogenesis of FK.