Abstract
Purpose :
Histatin peptides are potent anti-microbial agents that may have salubrious anti-inflammatory effects. Multiple ocular surface diseases, including dry eye disease, are driven by inflammation. We have found that histatin peptides are produced in lacrimal epithelia, ocular surface epithelia and promote migration of corneal epithelia. Further development of these peptides as therapeutic agents requires that target cells are able to uptake the peptides and that relevant inflammatory signaling cascades are affected. Thus, we assessed histatin peptide localization after exogenous application and effects on immune signaling in human corneal epithelia (HCE).
Methods :
Histatin peptide internalization was performed using an Alexa 488 tagged histatin-1. HCE cells were incubated with various concentrations at different time points. Similarly, endogenous expression of histatin peptide was performed using a histatin antibody (Anti- Histatin, ab 7002). Inflammation was induced using benzalkonium chloride (BAK) and hyperosmolar solution (HOsm). Cytokines related to corneal epithelial function and inflammatory ocular surface diseases (IL-6, IL-8, TNF-α) were assayed using qPCR, WB and ELISA techniques.
Results :
Experimental results show that exogenous peptide was internalized in most HCE cells with preferential localization to peri-nuclear area and that it was stable in cells up to 24 h (Figure 1). Application of histain peptide reduced the synthesis and secretion of multiple ocular surface disease relevant cytokines and chemokines. We also found that activation of inflammatory signaling pathways (p38, NF-kB) was reduced in response to histatin peptide.
Conclusions :
HCE cells were able to uptake histatin peptide reliably and histatin abrogated immune signaling in corneal epithelia at both the protein and gene level. Future studies will be necessary to understand the detailed mechanisms underlying these findings and apply them to clinically relevant models of disease.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.