title: Tryptophan end-tagging for promoted lipopolysaccharide interactions and anti-inflammatory effects.
abstract: The objective of the present study is the investigation of possibilities for boosting peptide anti-inflammatory effects by tryptophan end-tagging, including identification of underlying mechanisms for this. In doing so, effects of tryptophan end-tagging of KYE21 (KYEITTIHNLFRKLTHRLFRR), a peptide derived from heparin co-factor II, on membrane and lipopolysaccharide (LPS) interactions were investigated by ellipsometry, NMR, fluorescence spectroscopy, and circular dichroism measurements. Through its N-terminal W stretch, WWWKYE21 displays higher membrane binding, liposome rupture, and bacterial killing than unmodified KYE21. Analogously, W-tagging promotes binding to E. coli LPS and to its endotoxic lipid A moiety. Furthermore, WWWKYE21 causes more stable peptide/LPS complexes than KYE21, as evidenced by detailed NMR studies, adopting a pronounced helical conformation, with a large hydrophobic surface at the N-terminus due to the presence of W-residues, and a flexible C-terminus due to presence of several positively charged arginine residues. Mirroring its increased affinity for LPS and lipid A, WWWKYE21 displays strongly increased anti-inflammatory effect due to a combination of direct lipid A binding, peptide-induced charge reversal of cell membranes for LPS scavenging, and peptide-induced fragmentation of LPS aggregates for improved phagocytosis. Importantly, potent anti-inflammatory effects were observed at low cell toxicity, demonstrated for both monocytes and erythrocytes.
authors.affiliation: Department of Pharmacy, Uppsala University, SE-75232, Uppsala, Sweden. shalini.singh@farmaci.uu.se.
authors.forename: Shalini
authors.initials: S
authors.lastname: Singh
authors.affiliation: Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII (M), Kolkata, 700054, India.
authors.forename: Aritreyee
authors.initials: A
authors.lastname: Datta
authors.affiliation: Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-221 84, Lund, Sweden.|Lee Kong Chian School of Medicine, Nanyang Technological University, 11, Mandalay Road, 308232, Singapore.
authors.forename: Artur
authors.initials: A
authors.lastname: Schmidtchen
authors.affiliation: Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII (M), Kolkata, 700054, India.
authors.forename: Anirban
authors.identifier: 0000-0002-8752-2842
authors.initials: A
authors.lastname: Bhunia
authors.affiliation: Department of Pharmacy, Uppsala University, SE-75232, Uppsala, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Malmsten
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000494:pharmacology*; D002942:Circular Dichroism; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008050:Lipid A / Q000378:metabolism; D008070:Lipopolysaccharides / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D013211:Staphylococcus aureus / Q000187:drug effects; D000074084:THP-1 Cells; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D000893:Anti-Inflammatory Agents; D008050:Lipid A; D008070:Lipopolysaccharides; D010455:Peptides; D014364:Tryptophan