Temporin A and Related Frog Antimicrobial Peptides Use Formyl Peptide Receptor-Like 1 as a Receptor to Chemoattract Phagocytes

Abstract

Many mammalian antimicrobial peptides (AMPs) have multiple effects on antimicrobial immunity. We found that temporin A (TA), a representative frog-derived AMP, induced the migration of human monocytes, neutrophils, and macrophages with a bell-shaped response curve in a pertussis toxin-sensitive manner, activated p44/42 MAPK, and stimulated Ca2+ flux in monocytes, suggesting that TA is capable of chemoattracting phagocytic leukocytes by the use of a Giα protein-coupled receptor. TA-induced Ca2+ flux in monocytes was cross-desensitized by an agonistic ligand MMK-1 specific for formyl peptide receptor-like 1 (FPRL1) and vice versa, suggesting that TA uses FPRL1 as a receptor. This conclusion was confirmed by data showing that TA selectively stimulated chemotaxis of HEK 293 cells transfected with human FPRL1 or its mouse ortholog, murine formyl peptide receptor 2. In addition, TA elicited the infiltration of neutrophils and monocytes into the injection site of mice, indicating that TA is also functionally chemotactic in vivo. Examination of two additional temporins revealed that Rana-6 was also able to attract human phagocytes using FPRL1, but temporin 1P selectively induced the migration of neutrophils using a distinct receptor. Comparison of the chemotactic and antimicrobial activities of several synthetic analogues suggested that these activities are likely to rely on different structural characteristics. Overall, the results demonstrate that certain frog-derived temporins have the capacity to chemoattract phagocytes by the use of human FPRL1 (or its orthologs in other species), providing the first evidence suggesting the potential participation of certain amphibian antimicrobial peptides in host antimicrobial immunity.

Temporins A and B Stimulate Migration of HaCaT Keratinocytes and Kill Intracellular Staphylococcus aureus

“…After interaction with the plasma membrane, both temporins could directly or indirectly stimulate cell surface EGFR and activate downstream signaling cascades. In addition to this property, Ta has the ability to stimulate migration of human leukocytes, as reported previously (65): Ta was found to induce monocyte migration with a bell-shaped dose-response curve, with an optimal dose of 0.25 M. This is similar to what we found for the immortalized human keratinocytes. However, the phagocyte-attracting activity of Ta is mediated by a G i␣ proteincoupled receptor (65).…”

F2L, a Peptide Derived from Heme-Binding Protein, Chemoattracts Mouse Neutrophils by Specifically Activating Fpr2, the Low-Affinity N-Formylpeptide Receptor

“…FPRL1 is also a selective receptor for the lipid mediator lipoxin A4 and has been also named ALX (11,12). Recently, a panoply of additional unrelated peptide agonists have been identified for FPR and FPRL1, including synthetic peptides, pathogen-derived peptides, and various host proteins and peptides (7,(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). Only two naturally occurring peptide agonists have been identified to date for FPRL2: F2L and the neuropeptide humanin, both of which also activate FPRL1 (1,23).…”

Comparative Analysis of the Bactericidal Activities of Amphibian Peptide Analogues against Multidrug-Resistant Nosocomial Bacterial Strains

“…Among these, the esculentin-1 family includes 46-amino-acid-residue peptides that display the most potent antimicrobial activities with negligible toxic effects on eukaryotic cells (16). Analysis of the analogues of esculentin-1b has revealed that the antimicrobial properties of the peptide are confined to its N-terminal region from positions 1 to 18 [Esc (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)], which possesses the same net positive charge (ϩ5) as the full-length peptide (16).…”

“…They are among the smallest amphipathic ␣-helical AMPs (10 to 16 amino acids) found in nature to date, with a low net positive charge (from 0 to ϩ3) at neutral pH and with a broad spectrum of biological activities, such as antimicrobial functions, chemotactic effects on human phagocytes, and the ability to modulate secretory phospholipase A 2 activity (5,18). In addition, according to their ability to bind in vitro lipopolysaccharide (LPS; or endotoxin), the major component of the outer membrane of gram-negative bacteria, it has recently been demonstrated that temporins, alone or in combination with conventional antibiotics, reduce lethality in animal models of bacterial sepsis (6,9).…”