Phage display against corneal epithelial cells produced bioactive peptides that inhibit Aspergillus adhesion to the corneas

• Published in: PloS one 2012-03, Vol.7 (3), p.e33578-e33578
• Main Authors: Zhao, Ge, Li, Siyuan, Zhao, Wei, He, Kun, Xi, Haijie, Li, Weihua, Zhou, Qingjun, Wang, Yiqiang
• Format: Article
• Language: English
• Subjects: Adhesion; Affinity; Analysis; Analysis of Variance; Animal models; Animals; Aspergillus - physiology; Aspergillus fumigatus; Bacteria; Biology; Cell Adhesion - physiology; Cell culture; Communicable diseases; Computational Biology; Cornea; Development and progression; Disruption; Dissection; DNA Primers - genetics; Endothelial cells; Enzyme-Linked Immunosorbent Assay; Epithelial cells; Epithelial Cells - metabolism; Epithelium, Corneal - cytology; Epithelium, Corneal - microbiology; Extracellular matrix; Fibroblasts; Fungicides; Gene therapy; Homology; Host-pathogen interactions; Host-Pathogen Interactions - physiology; Humans; Infections; Infectious diseases; Infiltration; Inflammation; Interleukin 17; Interleukin-17 - metabolism; Keratitis; Keratitis - microbiology; Laboratories; Ligands; Mass spectrometry; Medicine; Membrane proteins; Mice; Mouse devices; MyD88 protein; Myeloid Differentiation Factor 88 - metabolism; Organ culture; Pathogenesis; Pathogens; Peptide Library; Peptides; Peptides - metabolism; Phage display; Phages; Physics; Proteins; Pseudomonas aeruginosa; Real-Time Polymerase Chain Reaction; Receptors; Scientific imaging; Sequence Analysis, DNA; Spirulina platensis; Stromal cells; Stromal Cells - metabolism; Studies; Synthetic peptides; Tetrazolium Salts; Thiazoles; Vectors (Biology)
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0033578

Dissection of host-pathogen interactions is important for both understanding the pathogenesis of infectious diseases and developing therapeutics for the infectious diseases like various infectious keratitis. To enhance the knowledge about pathogenesis infectious keratitis, a random 12-mer peptide phage display library was screened against cultured human corneal epithelial cells (HCEC). Fourteen sequences were obtained and BLASTp analysis showed that most of their homologue counterparts in GenBank were for defined or putative proteins in various pathogens. Based on known or predicted functions of the homologue proteins, ten synthetic peptides (Pc-A to Pc-J) were measured for their affinity to bind cells and their potential efficacy to interfere with pathogen adhesion to the cells. Besides binding to HCEC, most of them also bound to human corneal stromal cells and umbilical endothelial cells to different extents. When added to HCEC culture, the peptides induced expression of MyD88 and IL-17 in HCEC, and the stimulated cell culture medium showed fungicidal potency to various extents. While peptides Pc-C and Pc-E inhibited Aspergillus fumigatus (A.f) adhesion to HCEC in a dose-dependent manner, the similar inhibition ability of peptides Pc-A and Pc-B required presence of their homologue ligand Alb1p on A.f. When utilized in an eyeball organ culture model and an in vivo A.f keratitis model established in mouse, Pc-C and Pc-E inhibited fungal adhesion to corneas, hence decreased corneal disruption caused by inflammatory infiltration. Affinity pull-down of HCEC membrane proteins with peptide Pc-C revealed several molecules as potential receptors for this peptide. In conclusion, besides proving that phage display-selected peptides could be utilized to interfere with adhesion of pathogens to host cells, hence could be exploited for managing infectious diseases including infectious keratitis, we also proposed that the phage display technique and the resultant peptides could be used to explore host-pathogen interactions at molecular levels.