Functional analysis of the RNF114 psoriasis susceptibility gene implicates innate immune responses to double-stranded RNA in disease pathogenesis

Hum Mol Genet. 2011 Aug 15;20(16):3129-37. doi: 10.1093/hmg/ddr215. Epub 2011 May 13.

Abstract

Psoriasis is an immune-mediated skin disease, the aetiology of which remains poorly understood. In recent years, genome-wide association studies (GWAS) have helped to illuminate the molecular basis of this condition, by demonstrating the pathogenic involvement of multiple genes from the IL-23 and NF-κB pathways. A GWAS carried out by our group also identified RNF114, a gene encoding a novel ubiquitin binding protein, as a determinant for psoriasis susceptibility. Although the function of RNF114 is unknown, its paralogue RNF125 has been shown to regulate the RIG-I/MDA5 innate antiviral response. This signalling cascade, which is activated by the presence of double-stranded RNA (dsRNA) within the cytoplasm, induces the production of type I interferon (IFN) through the activation of the IRF3 and NF-κB transcription factors. Here, we explore the hypothesis that RNF114 may also modulate RIG-I/MDA5 signalling. We show that RNF114 associates with ubiquitinated proteins and that it is a soluble cytosolic protein that can be induced by interferons and synthetic dsRNA. Moreover, we demonstrate that RNF114 over-expression enhances NF-κb and IRF3 reporter activity and increases type I and type III IFN mRNA levels. These results indicate that RNF114 regulates a positive feedback loop that enhances dsRNA induced production of type I IFN. Thus, our data point to a novel pathogenic pathway, where dysregulation of RIG-I/MDA5 signalling leads to the over-production of type I IFN, a key early mediator of epithelial inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / genetics*
  • Carrier Proteins / metabolism
  • Cell Line
  • Cytoplasm / drug effects
  • Cytoplasm / metabolism
  • Genetic Predisposition to Disease*
  • Humans
  • Immunity, Innate / drug effects
  • Immunity, Innate / genetics*
  • Interferons / biosynthesis
  • Interferons / pharmacology
  • Poly I-C / pharmacology
  • Protein Binding / drug effects
  • Protein Transport / drug effects
  • Psoriasis / etiology
  • Psoriasis / genetics*
  • Psoriasis / immunology*
  • RNA, Double-Stranded / immunology*
  • Solubility / drug effects
  • Ubiquitin-Protein Ligases / metabolism
  • Ubiquitinated Proteins / metabolism
  • Up-Regulation / drug effects
  • Up-Regulation / genetics

Substances

  • Carrier Proteins
  • RNA, Double-Stranded
  • Ubiquitinated Proteins
  • Interferons
  • RNF114 protein, human
  • Ubiquitin-Protein Ligases
  • Poly I-C