title: Enhanced pulmonary absorption of a macromolecule through coupling to a sequence-specific phage display-derived peptide.
abstract: With the aim of identifying a peptide sequence that promotes pulmonary epithelial transport of macromolecule cargo we used a stringent peptide-phage display library screening protocol against rat lung alveolar epithelial primary cell cultures. We identified a peptide-phage clone (LTP-1) displaying the disulphide-constrained 7-mer peptide sequence, C-TSGTHPR-C, that showed significant pulmonary epithelial translocation across highly restrictive polarised cell monolayers. Cell biological data supported a differential alveolar epithelial cell interaction of the LTP-1 peptide-phage clone and the corresponding free synthetic LTP-1 peptide. Delivering select phage-clones to the intact pulmonary barrier of an isolated perfused rat lung (IPRL) resulted in 8.7% of lung deposited LTP-1 peptide-phage clone transported from the IPRL airways to the vasculature compared (p<0.05) to the cumulative transport of less than 0.004% for control phage-clone groups. To characterise phage-independent activity of LTP-1 peptide, the LTP-1 peptide was conjugated to a 53kDa anionic PAMAM dendrimer. Compared to respective peptide-dendrimer control conjugates, the LTP-1-PAMAM conjugate displayed a two-fold (bioavailability up to 31%) greater extent of absorption in the IPRL. The LTP-1 peptide-mediated enhancement of transport, when LTP-1 was either attached to the phage clone or conjugated to dendrimer, was sequence-dependent and could be competitively inhibited by co-instillation of excess synthetic free LTP-1 peptide. The specific nature of the target receptor or mechanism involved in LTP-1 lung transport remains unclear although the enhanced transport is enabled through a mechanism that is non-disruptive with respect to the pulmonary transport of hydrophilic permeability probes. This study shows proof-of principle that array technologies can be effectively exploited to identify peptides mediating enhanced transmucosal delivery of macromolecule therapeutics across an intact organ.
authors.affiliation: Welsh School of Pharmacy, Cardiff University, Cardiff, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Morris
authors.forename: Mathew W
authors.initials: MW
authors.lastname: Smith
authors.forename: Peter C
authors.initials: PC
authors.lastname: Griffiths
authors.forename: Neil B
authors.initials: NB
authors.lastname: McKeown
authors.forename: Mark
authors.initials: M
authors.lastname: Gumbleton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D050091:Dendrimers / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D004847:Epithelial Cells / Q000378:metabolism*; D008168:Lung / Q000378:metabolism*; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism; D051381:Rats
chemical_list: D050091:Dendrimers; C104700:PAMAM Starburst; D019151:Peptide Library; D010455:Peptides