Profile of antimicrobial peptides (AMPs) at the ocular surface

Abstract

Abstract Purpose Purpose: Antimicrobial peptides are eukaryotic analogues of antibiotics and serve as early effectors of innate defence. Our aim was to profile the spectrum of AMPs at the ocular surface in health and disease. Methods Methods: Reverse Transcription‐Polymerase Chain Reaction (RT‐PCR) and real time PCR techniques with primers for 21 known AMPs were employed to evaluate gene expression on the following human ocular surface (OS) samples: a) Impression cytology specimen of normals and patients suffering from bacterial, viral keratitis and acanthamoeba keratitis and dry eyes. b) OS cells from cadaver donors and c) cultured corneal epithelial cells from limbal explants. Over one hundred samples were thus studied. Results Results: AMP expression was observed in all the different groups of samples but was variable. Nine AMPs, namely Human Beta defensins (HBD) 1 to 4, Cathelicidin (LL37), Liver expressed antimicrobial peptides, LEAP‐1 and ‐2, DEFB‐109 and RNAse were detected. Of these, HBD3 was prominent in bacterial keratitis and LEAP 1 and LL37 in viral keratitis. LEAP 2 and LL37 showed an increased tendency of expression in dry eyes. DEFB‐109 was the only AMP found to show decreased expression in the inflammatory conditions studied. RNAse, the most potent of all AMPs was found in abundance at the OS. Conclusion Conclusions: The OS is endowed with a range of AMPs which contribute to defence against environmental microbes and also participate in other immune mediated, inflammatory and wound healing events. They hold promise as therapeutic agents against microbes and in modulation of inflammation and wound healing.