Abstract
Purpose: :
Antimicrobial peptides (AMPs) are cationic peptides with an essential role in host defense system. Ribonuclease (RNase) A superfamily have an intrinsic role in RNA metabolism, but more recently its role as an AMP has been identified in skin keratinocytes. This is the first report demonstrating an increased expression of RNase-7 mRNA in the presence of ocular inflammation and/or infection. In addition to its constitutive expression, RNase 7 was induced in SV40-immortalised human corneal epithelial cell line (S-HCEL) by interleukin-1 beta and tumor necrosis factor alpha.
Methods: :
In-vivo study: Total RNA was obtained from impression cytology samples of the conjunctiva and cornea of normal patients and of those with bacterial, viral, acanthamoeba or dry eye disease. Relative quantification of the RNase-7 mRNA was performed by means of real-time RT-PCR. In-vitro study: S-HCEL were collected after treatment with 10ng/ml of IL-1β and TNF-α at various time points (n=3; 0, 1, 3, 6 and 24hours). Total RNA was extracted and RNase-7 mRNA expression was determined by real-time RT-PCR.
Results: :
The constitutive expression of RNase-7 was demonstrated in all samples. The mean normalised expression of RNase-7 mRNA significantly increased in disease conditions particularly in acanthamoeba keratitis. RNase-7 mRNA demonstrated 2.5 fold expression upon IL-1β challenge and 2 fold expression when stimulated with TNF-α.
Keywords: cornea: epithelium • cytokines/chemokines • gene/expression