Expression pattern of antimicrobial peptides (AMPs) in acanthamoeba keratitis

Abstract

Abstract Purpose Acanthamoeba keratitis (AK) is a sight‐threatening ocular infection, which is more likely in contact lens wearer. Antimicrobial peptides(AMPs)are cationic polypeptides with wide‐spectrum activity against pathogens. We studied(1)the profile of AMP mRNA expression in ex‐vivo impression cytology (IC) specimen from normals and 5 AK patients &(2)compared AMP gene expression between ex‐vivo and in‐vitro cell culture samples. Methods a) IC samples were collected for Total RNA extraction and cDNA synthesis. Quantitative gene expression(qPCR)was employed to evaluate expression of Defensins,Cathelicidin,& Liver‐expressed AMPs (LEAPs).b) Immortalised human corneal epithelial cell line (HuCL) was incubated with trophozoites of Acanthamoeba castellanii for 24 hours and the supernatant analysed by BD cytometric bead array for pro‐inflammatory cytokines.The cells were processed for qPCR analyses. Results Variable expression of AMPs was observed in AK patients.Eight AMPs,Human Beta defensins(HBD)1 to 3,Cathelicidin (LL37,LEAP 1 and 2 and DEF 109 were detected.Of these HBD 1 to 3 and DEF 109 were shown to be reduced and whereas LEAP 1 & 2 were induced in AK specimen. Similarly, increased mRNA expression of LEAP 1 & 2 was also demonstrated in Acanthamoebae treated HuCL cultures.Whereas, HBDs showed the baseline expression when compare to untreated HuCLs. Conclusion This is a first study demonstrating AMP gene expression in AK. Differential expression pattern of these AMPs during AK may have important implications in understanding the pathogenesis of this blinding infection. Modulation of AMP defense barrier at the ocular surface or use of the AMP as a contact lens preservative agent may help to reduce the AK infections