Gene expression of defensin beta 1, 2 in various diseased corneal epithelium

Abstract

Abstract: : Purpose: Innate immunity may play an important role in immunologically compromised sites such as corneal epithelium. The defensin family is a major contributor to the innate immunity system and may protect corneal epithelium from various types of microbes. To elucidate the possible involvement of defensin genes for the protection of corneal epithelium, we investigated gene expression of defensin beta 1 (hBD1) and 2 (hBD2) in corneal epithelial cells among various corneal diseases. Methods: Corneal buttons were obtained at PKP surgery from patients with bullous keratopathy (n=13), keratoconus (n=3), corneal stromal opacity including syphilis keratitis (n=3), heridetary corneal dystrophy (n=3) and corneal scarring due to fungal infection (n=1). Two normal corneas obtained from US eye bank were used as control. Corneal epithelial cells were mechanically scraped from the corneal buttons with care in fear of possible contamination of stromal keratocytes. RNA was individually extracted from these samples with TRIZOL reagents and analysed for quantification of hBD1 and hBD2 gene expression by real–time RT–PCR. For normalization, relative amount of ribosomal RNA was quantitated in parallel. Results: Notable increase in gene expression of hBD2 was observed in the sample of fungal corneal infection. Some of the samples from bullous keratophathy and corneal dystrophy exhibited higher expression of hBD2 than the normal control corneas. The expression pattern of hBD1 differs from that of hBD2. Conclusions: Fungal infection may significantly promote hBD2 gene expression, which is likely to occur via stimulation of some cytokines. Discrepant expression pattern between hBD1 and hBD2 suggest the existence of different regulation paths for these genes.

Keywords: cornea: epithelium • gene/expression • inflammation