title: In planta production of ELPylated spidroin-based proteins results in non-cytotoxic biopolymers.
abstract: BACKGROUND
  Spider silk is a tear-resistant and elastic biopolymer that has outstanding mechanical properties. Additionally, exiguous immunogenicity is anticipated for spider silks. Therefore, spider silk represents a potential ideal biomaterial for medical applications. All known spider silk proteins, so-called spidroins, reveal a composite nature of silk-specific units, allowing the recombinant production of individual and combined segments.
  
  
  RESULTS
  In this report, a miniaturized spidroin gene, named VSO1 that contains repetitive motifs of MaSp1 has been synthesized and combined to form multimers of distinct lengths, which were heterologously expressed as elastin-like peptide (ELP) fusion proteins in tobacco. The elastic penetration moduli of layered proteins were analyzed for different spidroin-based biopolymers. Moreover, we present the first immunological analysis of synthetic spidroin-based biopolymers. Characterization of the binding behavior of the sera after immunization by competitive ELISA suggested that the humoral immune response is mainly directed against the fusion partner ELP. In addition, cytocompatibility studies with murine embryonic fibroblasts indicated that recombinant spidroin-based biopolymers, in solution or as coated proteins, are well tolerated.
  
  
  CONCLUSIONS
  The results show that spidroin-based biopolymers can induce humoral immune responses that are dependent on the fusion partner and the overall protein structure. Furthermore, cytocompatibility assays gave no indication of spidroin-derived cytotoxicity, suggesting that recombinant produced biopolymers composed of spider silk-like repetitive elements are suitable for biomedical applications.
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstrasse 3, 06466, Stadt Seeland, OT Gatersleben, Germany. hauptmann@ipk-gatersleben.de.
authors.forename: Valeska
authors.initials: V
authors.lastname: Hauptmann
authors.affiliation: Fraunhofer Institute for Mechanics of Materials, Walter-Hülse-Strasse 1, 06120, Halle/Saale, Germany. Matthias.Menzel@iwmh.fraunhofer.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Menzel
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstrasse 3, 06466, Stadt Seeland, OT Gatersleben, Germany. weichert@ipk-gatersleben.de.
authors.forename: Nicola
authors.initials: N
authors.lastname: Weichert
authors.affiliation: Department of Plastic, Hand and Reconstructive Surgery, Hannover Medical School, Podbielskistr. 380, 30659, Hannover, Germany. Reimers.Kerstin@mh-hannover.de.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Reimers
authors.affiliation: Fraunhofer Institute for Mechanics of Materials, Walter-Hülse-Strasse 1, 06120, Halle/Saale, Germany. Uwe.Spohn@iwmh.fraunhofer.de.
authors.forename: Uwe
authors.initials: U
authors.lastname: Spohn
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstrasse 3, 06466, Stadt Seeland, OT Gatersleben, Germany. conradu@ipk-gatersleben.de.
authors.forename: Udo
authors.initials: U
authors.lastname: Conrad
mesh_terms: D000818:Animals; D001704:Biopolymers / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D005349:Fibroins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D051379:Mice; D010455:Peptides / Q000276:immunology; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D047011:Silk; D013112:Spiders / Q000737:chemistry / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism
chemical_list: D001704:Biopolymers; D010455:Peptides; D011994:Recombinant Proteins; D047011:Silk; D005349:Fibroins