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Thiol-ene mediated neoglycosylation of collagen patches: a preliminary study

Significance Statement

Osteoarthritis (OA) is the most common form of degenerative joint disease and a leading cause of chronic disability, due to articular cartilage damages. Tissue engineering (TE) and biomaterial sciences may offer new strategies toward OA therapies. It has been recently reported that collagen O-glycosylation is involved in the regulatory level in the dynamic balance between collagen deposition and turnover with severe implications in health and diseases. Collagen is naturally glycosylated at hydroxylysine residues with β-galactosides or α -(1→2)-glucosyl-β-galactosides. It has been recently demonstrated that glycosylated collagen interacts with lectins, a family of proteins involved in glycan recognition and signalling in a variety of biological events. In this work, collagen-based patches (Figure A), mimicking the biochemical signals involved in collagen glycosylation were designed, synthesised and evaluated in vivo in osteoarthritic models. It should be noted that this is the first example of collagen chemical glycosylation (neoglycosylation) Thiol-ene photoclick chemistry was used for the neoglycosylation of collagen patches with a-glucose or b-galactose signalling moieties (Figure B). The reaction resulted effective as demonstrated by several techniques, such as Synchrotron Radiation induced Photoelectron Spectroscopy (SR-XPS), Fourier Transform Infrared (FTIR) Spectroscopy, Nuclear Magnetic Resonance (NMR). Collagen neoglycosylation was estimated to be around 60 % of total lysine/hydroxylysine content in the protein (Collagen type I from equine tendon). Enzyme-Linked Lectin Assay (ELLA) highlighted both the chemical glycosylation and the correct exposition of the monosaccharides for receptor recognition. OA models were obtained inducing the pathology by MIA (monosodium iodoacetate); MIA induced OA is featured by loss of spontaneous mobility due to knee joint arthritis and a prolonged secondary loss of mobility for more than four weeks due to pain and loss of function. In order to assess pathology regression, assessment of motor recovery of rat’s walking pattern (walking track analysis, WTA, Fig. C) was performed by recording its footprints and evaluating the sciatic function index. Thus, unglycosylated and glycosylated collagen patches 1 and 2 (Figure B) were implanted in OA models and WTA recorded after 45 days from pathology induction. The WTA (Figure C) indicated that both neoglucosylated collagen (1) and neogalactosylated collagen (2) patches caused a meaningful improvement of locomotor ability (100 = full functional impairment, 0 = full functional recovery), indicating that neoglycosylated collagen is more effective in promoting motor functional recovery than collagen itself. These results suggest neoglycosylated collagen patches responsiveness toward cartilage repair.

Thiol-ene Mediated Neoglycosylation of Collagen Patches- . Global Medical Discovery










Figure Legend 

  1. Size-tailored neoglycosylated collagen patches used as Implant in OA models.
  2. Size-tailored neoglycosylated collagen patches used as Implant in OA models.
  3. Walking Track Analysis (WTA) after 45 days post implantation. OA: osteoarthritic model; CTRL:  osteoarthritic model implanted with pristine collagen patch; 2:  osteoarthritic model implanted with neogalactosylated collagen patch 2; 1:  osteoarthritic model implanted with neoglucosylated collagen patch 1. (0: fully functional;100: fully unfunctional).

Journal Reference

Russo L, Battocchio C, Secchi V, Magnano E, Nappini S, Taraballi F, Gabrielli L, Comelli F, Papagni A, Costa B, Polzonetti G, Nicotra F, Natalello A, Doglia SM, Cipolla L. Langmuir. 2014;30(5):1336-42.

Department of Biotechnolgy and Biosciences, University of Milano-Bicocca , P.zza della Scienza 2, 20126 Milano, Italy.


Despite the relevance of carbohydrates as cues in eliciting specific biological responses, the covalent surface modification of collagen-based matrices with small carbohydrate epitopes has been scarcely investigated. We report thereby the development of an efficient procedure for the chemoselective neoglycosylation of collagen matrices (patches) via a thiol-ene approach, between alkene-derived monosaccharides and the thiol-functionalized material surface. Synchrotron radiation-induced X-ray photoelectron spectroscopy (SR-XPS), Fourier transform-infrared (FT-IR), and enzyme-linked lectin assay (ELLA) confirmed the effectiveness of the collagen  neoglycosylation.  Preliminary biological evaluation in osteoarthritic models is reported. The proposed methodology can be extended to any thiolated surface for the development  f smart biomaterials for innovative approaches in regenerative medicine.

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