title: The random co-polymer glatiramer acetate rapidly kills primary human leukocytes through sialic-acid-dependent cell membrane damage.
abstract: The formulation glatiramer acetate (GA) is widely used in therapy of multiple sclerosis. GA consists of random copolymers of four amino acids, in ratios that produce a predominantly positive charge and an amphipathic character. With the extraordinary complexity of the drug, several pharmacological modes-of-action were suggested, but so far none, which rationalizes the cationicity and amphipathicity as part of the mode-of-action. Here, we report that GA rapidly kills primary human T lymphocytes and, less actively, monocytes. LL-37 is a cleavage product of human cathelicidin with important roles in innate immunity. It shares the positive charge and amphipathic character of GA, and, as shown here, also the ability to kill human leukocyte. The cytotoxicity of both compounds depends on sialic acid in the cell membrane. The killing was associated with the generation of CD45+ debris, derived from cell membrane deformation. Nanoparticle tracking analysis confirmed the formation of such debris, even at low GA concentrations. Electric cell-substrate impedance sensing measurements also recorded stable alterations in T lymphocytes following such treatment. LL-37 forms oligomers through weak hydrophobic contacts, which is critical for the lytic properties. In our study, SAXS showed that GA also forms this type of contacts. Taken together, our study offers new insight on the immunomodulatory mode-of-action of positively charged co-polymers. The comparison of LL-37 and GA highlights a consistent requirement of certain oligomeric and chemical properties to support cytotoxic effects of cationic polymers targeting human leukocytes.
authors.affiliation: Dept. of Biomedicine, Aarhus University, The Bartholin Building (1240), Bartholins Allé 6, DK-8000 Aarhus C, Denmark. Electronic address: stig.hill@biomed.au.dk.
authors.forename: Stig Hill
authors.initials: SH
authors.lastname: Christiansen
authors.affiliation: Dept. of Biomedicine, Aarhus University, The Bartholin Building (1240), Bartholins Allé 6, DK-8000 Aarhus C, Denmark. Electronic address: xianwei.zhang@biomed.au.dk.
authors.forename: Xianwei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Dept. of Biomedicine, Aarhus University, The Bartholin Building (1240), Bartholins Allé 6, DK-8000 Aarhus C, Denmark. Electronic address: juul-madsen@biomed.au.dk.
authors.forename: Kristian
authors.initials: K
authors.lastname: Juul-Madsen
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark. Electronic address: mhvam@inano.au.dk.
authors.forename: Michael Lykke
authors.initials: ML
authors.lastname: Hvam
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark. Electronic address: bsv@chem.au.dk.
authors.forename: Brian Stougaard
authors.initials: BS
authors.lastname: Vad
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark. Electronic address: mab@inano.au.dk.
authors.forename: Manja Annette
authors.initials: MA
authors.lastname: Behrens
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark; Dept. of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads, Building 345C, DK-2800 Kgs. Lyngby, Denmark. Electronic address: idathyge@gmail.com.
authors.forename: Ida Lysgaard
authors.initials: IL
authors.lastname: Thygesen
authors.affiliation: Dept. of Biomedicine, Aarhus University, The Bartholin Building (1240), Bartholins Allé 6, DK-8000 Aarhus C, Denmark. Electronic address: jalilian.b@gmail.com.
authors.forename: Babak
authors.initials: B
authors.lastname: Jalilian
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark. Electronic address: jsp@chem.au.dk.
authors.forename: Jan Skov
authors.initials: JS
authors.lastname: Pedersen
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark; The Lundbeck Foundation Nanomedicine Center for Individualized Management of Tissue Damage and Regeneration (LUNA), Aarhus University, Denmark. Electronic address: kenh@inano.au.dk.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Howard
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark. Electronic address: dao@inano.au.dk.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Otzen
authors.affiliation: Dept. of Biomedicine, Aarhus University, The Bartholin Building (1240), Bartholins Allé 6, DK-8000 Aarhus C, Denmark; Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark; The Lundbeck Foundation Nanomedicine Center for Individualized Management of Tissue Damage and Regeneration (LUNA), Aarhus University, Denmark; MEMBRANES Research Center, Aarhus University, Denmark; Center for Neurodegenerative Inflammation Prevention (NEURODIN), Aarhus University, Denmark. Electronic address: vorup-jensen@biomed.au.dk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Vorup-Jensen
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D002478:Cells, Cultured; D005434:Flow Cytometry; D000068717:Glatiramer Acetate / Q000737:chemistry*; D006801:Humans; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009438:Neuraminic Acids / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D053838:Scattering, Small Angle; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D014961:X-Ray Diffraction; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D008081:Liposomes; D009438:Neuraminic Acids; D011108:Polymers; D000068717:Glatiramer Acetate; D054804:Cathelicidins
keywords: Cathelicidins; Cationic co-polymers; Glatiramoids; Immunotherapy