PURPOSE: The release of N-acetyl-proline-glycine-proline (PGP), a chemoattractant resulting from direct alkaline hydrolysis of corneal proteins, is believed to be the initial trigger for neutrophil invasion into the alkali-injured cornea. The purpose of this study is twofold: (1) to compare the activity of N-acetyl-PGP with the bioactivities of other similar synthetic peptides in an effort to uncover information about this chemoattractant molecule, and (2) to test these peptide analogs as potential antagonists of N-acetyl-PGP. METHODS: The polarization assay was used to measure the potential chemotactic response of human neutrophils to peptides. Bioactivity was expressed as the peptide concentration required to produce 50% neutrophil polarization (EC50). Antagonist activity was expressed as the peptide concentration required to produce 50% inhibition (ID50) of polarization activated by N-acetyl-PGP. RESULTS: Peptide bioactivities (EC50) were ranked as follows: APGPR (0.34 mM) > N-acetyl-PGP (0.5 mM) > N-(PGP)4-PGLG (3 mM) = t-Boc-PGP (3 mM) > N-acetyl-PG (3.4 mM) > N-methyl-PGP (15 mM) = PGP (15 mM) > peptides without detectable activity (t-Boc-PGP-OMe, N-acetyl-P, PG, PGG, GP, GG and gly-pro-hyp). Peptides with no detectable bioactivity were tested as potential antagonists of neutrophil polarization induced by N-acetyl-PGP. Gly-Pro-Hyp inhibited N-acetyl-PGP activation of polarization at 20 mM (ID50). No other synthetic peptide demonstrated a capacity for inhibition. CONCLUSIONS: The minimum requirement to elicit bioactivity was the presence of PGP alone or derivatives of PG in which the N-terminal proline is blocked. Using this approach, active and inactive mimetic peptides of N-acetyl-PGP were produced. The most active peptide, APGPR, was equal to or slightly greater than N-acetyl-PGP, suggesting that more potent analogs might be designed. Gly-pro-hyp was the only inactive peptide analog to inhibit the chemoattractant.
PURPOSE: The release of N-acetyl-proline-glycine-proline (PGP), a chemoattractant resulting from direct alkaline hydrolysis of corneal proteins, is believed to be the initial trigger for neutrophil invasion into the alkali-injured cornea. The purpose of this study is twofold: (1) to compare the activity of N-acetyl-PGP with the bioactivities of other similar synthetic peptides in an effort to uncover information about this chemoattractant molecule, and (2) to test these peptide analogs as potential antagonists of N-acetyl-PGP. METHODS: The polarization assay was used to measure the potential chemotactic response of human neutrophils to peptides. Bioactivity was expressed as the peptide concentration required to produce 50% neutrophil polarization (EC50). Antagonist activity was expressed as the peptide concentration required to produce 50% inhibition (ID50) of polarization activated by N-acetyl-PGP. RESULTS: Peptide bioactivities (EC50) were ranked as follows: APGPR (0.34 mM) > N-acetyl-PGP (0.5 mM) > N-(PGP)4-PGLG (3 mM) = t-Boc-PGP (3 mM) > N-acetyl-PG (3.4 mM) > N-methyl-PGP (15 mM) = PGP (15 mM) > peptides without detectable activity (t-Boc-PGP-OMe, N-acetyl-P, PG, PGG, GP, GG and gly-pro-hyp). Peptides with no detectable bioactivity were tested as potential antagonists of neutrophil polarization induced by N-acetyl-PGP. Gly-Pro-Hyp inhibited N-acetyl-PGP activation of polarization at 20 mM (ID50). No other synthetic peptide demonstrated a capacity for inhibition. CONCLUSIONS: The minimum requirement to elicit bioactivity was the presence of PGP alone or derivatives of PG in which the N-terminal proline is blocked. Using this approach, active and inactive mimetic peptides of N-acetyl-PGP were produced. The most active peptide, APGPR, was equal to or slightly greater than N-acetyl-PGP, suggesting that more potent analogs might be designed. Gly-pro-hyp was the only inactive peptide analog to inhibit the chemoattractant.
Authors: Philip J O'Reilly; Matthew T Hardison; Patricia L Jackson; Xin Xu; Robert J Snelgrove; Amit Gaggar; F Shawn Galin; J Edwin Blalock Journal: J Neuroimmunol Date: 2009-10-28 Impact factor: 3.478
Authors: Robert J Snelgrove; Patricia L Jackson; Matthew T Hardison; Brett D Noerager; Andrew Kinloch; Amit Gaggar; Suresh Shastry; Steven M Rowe; Yun M Shim; Tracy Hussell; J Edwin Blalock Journal: Science Date: 2010-09-02 Impact factor: 47.728
Authors: Saskia Braber; Pim J Koelink; Paul A J Henricks; Patricia L Jackson; Frans P Nijkamp; Johan Garssen; Aletta D Kraneveld; J Edwin Blalock; Gert Folkerts Journal: Am J Physiol Lung Cell Mol Physiol Date: 2010-11-26 Impact factor: 5.464
Authors: Saskia A Overbeek; Paul A J Henricks; Anja I Srienc; Pim J Koelink; Petra de Kruijf; Herman D Lim; Martine J Smit; Guido J R Zaman; Johan Garssen; Frans P Nijkamp; Aletta D Kraneveld; Gert Folkerts Journal: Eur J Pharmacol Date: 2011-03-31 Impact factor: 4.432
Authors: J Michael Wells; Philip J O'Reilly; Tomasz Szul; Daniel I Sullivan; Guy Handley; Chris Garrett; Carmel M McNicholas; Mojtaba Abdul Roda; Bruce E Miller; Ruth Tal-Singer; Amit Gaggar; Stephen I Rennard; Patricia L Jackson; J Edwin Blalock Journal: Am J Respir Crit Care Med Date: 2014-07-01 Impact factor: 21.405
Authors: Anneke H van Houwelingen; Nathaniel M Weathington; Vivienne Verweij; J Edwin Blalock; Frans P Nijkamp; Gert Folkerts Journal: FASEB J Date: 2008-06-12 Impact factor: 5.191