Abstract
Purpose :
The role of bacterial proteases inupon microbial pathogenesis of the cornea has been well studied; however, little work has gone into the effect these proteases have on corneal wound healing and cell migration. Serratia marcescens secretomes (proteins, lipids and other molecules) efficiently inhibit corneal cell migration, but no secreted proteins have been identified as being responsible for the phenotype. In this study we investigated the bacterial factors required to inhibit wound healing using an in vitro corneal epithelial model, specifically by analyzing the impact of bacterial metalloproteases.
Methods :
Stratified layers of human corneal limbal epithelial cells were exposed to normalized and filter sterilized culture supernatants of Serratia marcescens, Pseudomonas aeruginosa, and Klebsiella aerogenes. Purified metalloproteases and the P. aeruginosa metalloprotease inhibitor AprI were also used to test wound healing.
Results :
Mutation of individual S. marcescens metalloprotase genes prtS, slpB, and slpE did not affect this phenotype; however, mutation of all three genes eliminated the inhibitory phenotype. This suggested that the three metalloproteases had redundant function. Consistently, plasmid-based expression of each of the individual protease genes restored inhibition ability. Furthermore, exogenous addition of purified PrtS, SlpB, and SlpE metalloproteases was sufficient to inhibit cell migration, and the metalloprotease inhibitor protein, AprI, from Pseudomonas aeruginosa restored migration. The role of similar metalloproteases from other important pathogens was addressed.
Conclusions :
Bacterial metalloproteases can inhibit cellular migration and our results suggest that protease inhibitors may be useful in experimental therapeutic approaches for chronic wounds or to promote wound healing.
This is a 2021 ARVO Annual Meeting abstract.