title: Comparative study of the skin penetration of protein transduction domains and a conjugated peptide.
abstract: OBJECTIVE
  We examined the ability of a protein transduction domain (PTD), YARA, to penetrate in the skin and carry a conjugated peptide, P20. The results with YARA were compared to those of a well-known PTD (TAT) and a control, nontransducing peptide (YKAc). The combined action of PTDs and lipid penetration enhancers was also tested.
  
  
  METHODS
  YARA, TAT, YKAc, P20, YARA-P20, and TAT-P20 were synthesized by Fmoc chemistry. Porcine ear skin mounted in a Franz diffusion cell was used to assess the topical and transdermal delivery of fluorescently tagged peptides in the presence or absence of lipid penetration enhancers (monoolein or oleic acid). The peptide concentrations in the skin (topical delivery) and receptor phase (transdermal delivery) were assessed by spectrofluorimetry. Fluorescence microscopy was used to visualize the peptides in different skin layers.
  
  
  RESULTS
  YARA and TAT, but not YKAc, penetrated abundantly in the skin and permeated modestly across this tissue. Monoolein and oleic acid did not enhance the topical and transdermal delivery of TAT or YARA but increased the topical delivery of YKAc. Importantly, YARA and TAT carried a conjugated peptide, P20, into the skin, but the transdermal delivery was very small. Fluorescence microscopy confirmed that free and conjugated PTDs reached viable layers of the skin.
  
  
  CONCLUSIONS
  YARA and TAT penetrate in the porcine ear skin in vitro and carry a conjugated model peptide, P20, with them. Thus, the use of PTDs can be a useful strategy to increase topical delivery of peptides for treatment of cutaneous diseases.
authors.affiliation: Biodesign Institute, Arizona State University, Tempe, Arizona, USA.
authors.forename: Luciana B
authors.initials: LB
authors.lastname: Lopes
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Brophy
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Furnish
authors.forename: Charles R
authors.initials: CR
authors.lastname: Flynn
authors.forename: Olivia
authors.initials: O
authors.lastname: Sparks
authors.forename: Padmini
authors.initials: P
authors.lastname: Komalavilas
authors.forename: Lokesh
authors.initials: L
authors.lastname: Joshi
authors.forename: Alyssa
authors.initials: A
authors.lastname: Panitch
authors.forename: M Vitoria L B
authors.initials: MV
authors.lastname: Bentley
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004423:Ear / Q000473:pathology; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D008856:Microscopy, Fluorescence / Q000379:methods; D010455:Peptides / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology*; D012867:Skin / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D012869:Skin Absorption / Q000187:drug effects / Q000502:physiology*; D013501:Surface-Active Agents / Q000737:chemistry / Q000494:pharmacology; D013552:Swine; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D010455:Peptides; D013501:Surface-Active Agents; D016650:Fluorescein-5-isothiocyanate