title: The Impact of Chain Length and Flexibility in the Interaction between Sulfated Alginates and HGF and FGF-2.
abstract: Alginate is a promising polysaccharide for use in biomaterials as it is biologically inert. One way to functionalize alginate is by chemical sulfation to emulate sulfated glycosaminoglycans, which interact with a variety of proteins critical for tissue development and homeostasis. In the present work we studied the impact of chain length and flexibility of sulfated alginates for interactions with FGF-2 and HGF. Both growth factors interact with defined sequences of heparan sulfate (HS) at the cell surface or in the extracellular matrix. Whereas FGF-2 interacts with a pentasaccharide sequence containing a critical 2-O-sulfated iduronic acid, HGF has been suggested to require a highly sulfated HS/heparin octasaccharide. Here, oligosaccharides of alternating mannuronic and guluronic acid (MG) were sulfated and assessed by their relative efficacy at releasing growth factor bound to the surface of myeloma cells. 8-mers of sulfated MG (SMG) alginate showed significant HGF release compared to shorter fragments, while the maximum efficacy was achieved at a chain length average of 14 monosaccharides. FGF-2 release required a higher concentration of the SMG fragments, and the 14-mer was less potent compared to an equally sulfated high-molecular weight SMG. Sulfated mannuronan (SM) was subjected to periodate oxidation to increase chain flexibility. To assess the change in flexibility, the persistence length was estimated by SEC-MALLS analysis and the Bohdanecky approach to the worm-like chain model. A high degree of oxidation of SM resulted in approximately twice as potent HGF release compared to the nonoxidized SM alginate. The release of FGF-2 also increased with the degree of oxidation, but to a lower degree compared to that of HGF. It was found that the SM alginates were more efficient at releasing FGF-2 than the SMG alginates, indicating a greater dependence on monosaccharide identity and charge orientation over chain flexibility and charge density.
authors.affiliation: Department of Biotechnology, Norwegian University of Science and Technology , Sem Sælands vei 6/8, 7034 Trondheim, Norway.
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Arlov
authors.affiliation: Department of Biotechnology, Norwegian University of Science and Technology , Sem Sælands vei 6/8, 7034 Trondheim, Norway.
authors.forename: Finn L
authors.initials: FL
authors.lastname: Aachmann
authors.affiliation: K.G. Jebsen Center for Myeloma Research and Centre of Molecular Inflammation Research (CEMIR), Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology , Prinsesse Kristinas gate 1, 7030 Trondheim, Norway.|Department of Hematology, St. Olav University Hospital , Erling Skjalgsons Gate 1, 7030 Trondheim, Norway.
authors.forename: Emadoldin
authors.initials: E
authors.lastname: Feyzi
authors.affiliation: K.G. Jebsen Center for Myeloma Research and Centre of Molecular Inflammation Research (CEMIR), Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology , Prinsesse Kristinas gate 1, 7030 Trondheim, Norway.
authors.forename: Anders
authors.initials: A
authors.lastname: Sundan
authors.affiliation: Department of Biotechnology, Norwegian University of Science and Technology , Sem Sælands vei 6/8, 7034 Trondheim, Norway.
authors.forename: Gudmund
authors.initials: G
authors.lastname: Skjåk-Bræk
mesh_terms: D000464:Alginates / Q000737:chemistry*; D045744:Cell Line, Tumor; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D020723:Glucuronic Acid / Q000737:chemistry; D006025:Glycosaminoglycans / Q000737:chemistry; D006497:Heparan Sulfate / Q000737:chemistry; D017228:Hepatocyte Growth Factor / Q000378:metabolism*; D006603:Hexuronic Acids / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D009101:Multiple Myeloma / Q000188:drug therapy; D009844:Oligosaccharides / Q000737:chemistry / Q000494:pharmacology; D013431:Sulfates / Q000737:chemistry*
chemical_list: D000464:Alginates; D016222:Fibroblast Growth Factor 2; D020723:Glucuronic Acid; D006025:Glycosaminoglycans; D006497:Heparan Sulfate; D017228:Hepatocyte Growth Factor; D006603:Hexuronic Acids; D009844:Oligosaccharides; D013431:Sulfates; C066855:HGF protein, human; C007896:guluronic acid; C008324:mannuronic acid