title: Collagen tethering of synthetic human antimicrobial peptides cathelicidin LL37 and its effects on antimicrobial activity and cytotoxicity.
abstract: Wound infections, particularly of chronic wounds, pose a substantial challenge for designing antimicrobial dressings that are both effective against pathogens, and do not interfere with wound healing. Due to their broad-spectrum antimicrobial and immunomodulatory activities, naturally-occurring antimicrobial peptides (AMPs) are promising alternative treatments. However, their cytotoxicity at high concentrations and poor stability hinders their clinical use. To mitigate these undesirable properties, we investigated the effects of tethering human AMP cathelicidin LL37 to collagen, one of the main extracellular matrix proteins in wound sites, secreted by fibroblasts, and in commercially-available wound dressings. The active domain of human AMP cathelicidin, LL37, and two chimeric peptides containing LL37 fused to collagen binding domains (derived from collagenase - cCBD-LL37 or fibronectin - fCBD-LL37) were synthesized and adsorbed to PURACOL® type I collagen scaffolds. After 14days, 73%, 81% and 99% of LL37, cCBD-LL37 and fCBD-LL37, respectively, was retained on the scaffolds and demonstrated undiminished antimicrobial activity when challenged with both Gram-positive and Gram-negative bacterial strains. Loaded scaffolds were not cytotoxic to fibroblasts despite retaining peptides at concentrations 24 times higher than the reported cytotoxic concentrations in solution. These findings indicate that biopolymer-tethered AMPs may represent a viable alternative for preventing and treating wound infection while also supporting tissue repair.
  
  
  
  Over 6.5million people annually in the United States suffer chronic wounds; many will become infected with antibiotic-resistant bacteria. Treatments used to prevent and fight infection are toxic and may hinder wound healing. AMPs are broad-spectrum antimicrobials that also promote healing; however, their instability and toxicity are major challenges. To overcome treatment gaps, we functionalized collagen scaffolds with chimeric antimicrobial peptides (AMPs) with collagen binding domains to create antimicrobial and non-cytotoxic scaffolds that may promote healing. This is the first report of CBD-mediated delivery of AMPs onto collagen scaffolds that demonstrates no cytotoxicity toward fibroblasts. This study also suggests that retention of antimicrobial activity is CBD-dependent, which provides foundations for fundamental studies of CBD-AMP mechanisms and clinical explorations.
authors.affiliation: Dept. of Chemical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, United States.
authors.forename: Lindsay D
authors.initials: LD
authors.lastname: Lozeau
authors.affiliation: Dept. of Biomedical Engineering, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan, Italy; Dept. of Biomedical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, United States.
authors.forename: Jonian
authors.initials: J
authors.lastname: Grosha
authors.affiliation: Dept. of Biomedical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, United States; Dept. of Biology and Biotechnology, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, United States.
authors.forename: Denis
authors.initials: D
authors.lastname: Kole
authors.affiliation: Dept. of Biomedical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, United States; Dept. of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, United States.
authors.forename: Fioleda
authors.initials: F
authors.lastname: Prifti
authors.affiliation: Dept. of Biology and Biotechnology, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, United States; Center for Biomedical Sciences and Engineering, University of Nova Gorica, Vipavska cesta, 5000 Nova Gorica, Slovenia.
authors.forename: Tanja
authors.initials: T
authors.lastname: Dominko
authors.affiliation: Dept. of Chemical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, United States.
authors.forename: Terri A
authors.initials: TA
authors.lastname: Camesano
authors.affiliation: Dept. of Biomedical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, United States. Electronic address: mrolle@wpi.edu.
authors.forename: Marsha W
authors.initials: MW
authors.lastname: Rolle
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000737:chemistry; D018407:Bacterial Physiological Phenomena / Q000187:drug effects*; D001458:Bandages / Q000382:microbiology*; D054804:Cathelicidins / Q000008:administration & dosage* / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000008:administration & dosage* / Q000737:chemistry; D004867:Equipment Design; D016326:Extracellular Matrix Proteins / Q000737:chemistry; D005347:Fibroblasts / Q000187:drug effects*; D006801:Humans; D010446:Peptide Fragments / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D054804:Cathelicidins; D003692:Delayed-Action Preparations; D016326:Extracellular Matrix Proteins; D010446:Peptide Fragments; C534394:cathelicidin LL-37 (18-29), human; D003094:Collagen
keywords: Antimicrobial peptides; Collagen; Collagen-binding domain; LL37; Tether; Wound healing