Poster Presentation 12th Australian Peptide Conference 2017

Development of scaffold-based peptide scavengers for inhibition of autoantibodies in rheumatoid arthritis (#84)

Camilla Eriksson 1 , Sunithi Gunasekera 1 , Cátia Fernandes-Cerqueira 2 , Per-Johan Jakobsson 2 , Ulf Göransson 1
  1. Division of Pharmacognosy, Uppsala University, Uppsala, Sweden
  2. Department of Rheumatology, Karolinska University Hospital, Stockholm, Sweden

INTRODUCTION

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease characterised by painful deformation and degradation of bone and cartilage in synovial joints. A new class of rheumatoid arthritis-specific autoantibodies has recently been discovered that target citrullinated proteins: the so-called Anti-Citrullinated Protein Antibodies (ACPA)1. Their high specificity for RA2 and early appearance in the disease course makes them important serological markers. Several lines of evidence support the involvement of ACPA in RA pathogenesis3 and it has been hypothesised that inhibition of these autoantibodies could be useful in development of novel therapies4. Using known target sequences and stable cyclic peptide scaffolds with epitope-stabilising properties5,6, we developed a set of citrullinated peptide analogues with in vitro ACPA neutralising activity.

MATERIALS AND METHODS

Citrullinated peptides and their corresponding arginine-controls were synthesised using FMOC-SPPS, purified by RP-HPLC and analysed by analytical LC-UV and MS. Specifically, scaffold peptides were synthesised by grafting the citrullinated epitope onto the scaffold peptide sunflower trypsin inhibitor 1 (SFTI-1)6. Peptides at different concentrations were incubated with ACPA purified from patient sera and neutralising activity was assessed by measuring the remaining ACPA reactivity to surrogate peptide targets in CCP-2 ELISA.

RESULTS

The citrullinated peptide analogues demonstrated autoantibody neutralising activity when compared to arginine controls. In addition, improved neutralising activity was observed for the scaffold peptide analogues in comparison to their corresponding linear peptide epitopes.

CONCLUSIONS

These results further support the potential of scaffold-based citrullinated peptides as inhibitors of anti-citrullinated protein autoantibodies in rheumatoid arthritis.

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