title: Cathelicidin LL-37 increases lung epithelial cell stiffness, decreases transepithelial permeability, and prevents epithelial invasion by Pseudomonas aeruginosa.
abstract: In addition to its antibacterial activity, the cathelicidin-derived LL-37 peptide induces multiple immunomodulatory effects on host cells. Atomic force microscopy, F-actin staining with phalloidin, passage of FITC-conjugated dextran through a monolayer of lung epithelial cells, and assessment of bacterial outgrowth from cells subjected to Pseudomonas aeruginosa infection were used to determine LL-37's effect on epithelial cell mechanical properties, permeability, and bacteria uptake. A concentration-dependent increase in stiffness and F-actin content in the cortical region of A549 cells and primary human lung epithelial cells was observed after treatment with LL-37 (0.5-5 μM), sphingosine 1-phosphate (1 μM), or LPS (1 μg/ml) or infection with PAO1 bacteria. Other cationic peptides, such as RK-31, KR-20, or WLBU2, and the antibacterial cationic steroid CSA-13 did not reproduce the effect of LL-37. A549 cell pretreatment with WRW4, an antagonist of the transmembrane formyl peptide receptor-like 1 protein attenuated LL-37's ability to increase cell stiffness. The LL-37-mediated increase in cell stiffness was accompanied by a decrease in permeability and P. aeruginosa uptake by a confluent monolayer of polarized normal human bronchial epithelial cells. These results suggested that the antibacterial effect of LL-37 involves an LL-37-dependent increase in cell stiffness that prevents epithelial invasion by bacteria.
authors.affiliation: Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Fitzroy J
authors.initials: FJ
authors.lastname: Byfield
authors.forename: Marek
authors.initials: M
authors.lastname: Kowalski
authors.forename: Katrina
authors.initials: K
authors.lastname: Cruz
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Leszczyńska
authors.forename: Andrzej
authors.initials: A
authors.lastname: Namiot
authors.forename: Paul B
authors.initials: PB
authors.lastname: Savage
authors.forename: Robert
authors.initials: R
authors.lastname: Bucki
authors.forename: Paul A
authors.initials: PA
authors.lastname: Janmey
mesh_terms: D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000502:physiology*; D054804:Cathelicidins / Q000502:physiology*; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000276:immunology*; D002464:Cell Migration Inhibition / Q000187:drug effects / Q000276:immunology*; D002478:Cells, Cultured; D006801:Humans; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D008969:Molecular Sequence Data; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000472:pathogenicity*; D020545:Respiratory Mucosa / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology*
chemical_list: D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins