Rare genetic variants in interleukin-37 link this anti-inflammatory cytokine to the pathogenesis and treatment of gout

  • Klück, Viola
  • van Deuren, Rosanne C
  • Cavalli, Giulio
  • Shaukat, Amara
  • Arts, Peer
  • Cleophas, Maartje C
  • Crisan, Tania O
  • Tausche, Anne-Kathrin
  • Riches, Philip
  • Dalbeth, Nicola
  • Stamp, Lisa K
  • Hindmarsh, Jennie Harré
  • Jansen, Tim L Th A
  • Janssen, Matthijs
  • Steehouwer, Marloes
  • Lelieveld, Stefan
  • van de Vorst, Maartje
  • Gilissen, Christian
  • Dagna, Lorenzo
  • Van de Veerdonk, Frank L
  • Eisenmesser, Elan Z
  • Kim, SooHyun
  • Merriman, Tony R
  • Hoischen, Alexander
  • Netea, Mihai G
  • Dinarello, Charles A
  • Joosten, Leo AB
Annals of the Rheumatic Diseases 79(4):p 536-544, April 2020. | DOI: 10.1136/annrheumdis-2019-216233

Objective

Gout is characterised by severe interleukin (IL)-1-mediated joint inflammation induced by monosodium urate crystals. Since IL-37 is a pivotal anti-inflammatory cytokine suppressing the activity of IL-1, we conducted genetic and functional studies aimed at elucidating the role of IL-37 in the pathogenesis and treatment of gout.

Methods

Variant identification was performed by DNA sequencing of all coding bases of IL37 using molecular inversion probe-based resequencing (discovery cohort: gout n=675, controls n=520) and TaqMan genotyping (validation cohort: gout n=2202, controls n=2295). Predictive modelling of the effects of rare variants on protein structure was followed by in vitro experiments evaluating the impact on protein function. Treatment with recombinant IL-37 was evaluated in vitro and in vivo in a mouse model of gout.

Results

We identified four rare variants in IL37 in six of the discovery gout patients; p.(A144P), p.(G174Dfs*16), p.(C181*) and p.(N182S), whereas none emerged in healthy controls (Fisher's exact p-value=0.043). All variants clustered in the functional domain of IL-37 in exon 5 (p-value=5.71×10−5). Predictive modelling and functional studies confirmed loss of anti-inflammatory functions and we substantiated the therapeutic potential of recombinant IL-37 in the treatment of gouty inflammation. Furthermore, the carrier status of p.(N182S)(rs752113534) was associated with increased risk (OR=1.81, p-value=0.031) of developing gout in hyperuricaemic individuals of Polynesian ancestry.

Conclusion

Here, we provide genetic as well as mechanistic evidence for the role of IL-37 in the pathogenesis of gout, and highlight the therapeutic potential of recombinant IL-37 for the treatment of gouty arthritis.

Copyright © 2020 BMJ Publishing Group Ltd and European League Against Rheumatism