Pluripotent stem cell models of Blau syndrome reveal an IFN-γ-dependent inflammatory response in macrophages

J Allergy Clin Immunol. 2018 Jan;141(1):339-349.e11. doi: 10.1016/j.jaci.2017.04.013. Epub 2017 Jun 3.


Background: Blau syndrome, or early-onset sarcoidosis, is a juvenile-onset systemic granulomatosis associated with a mutation in nucleotide-binding oligomerization domain 2 (NOD2). The underlying mechanisms of Blau syndrome leading to autoinflammation are still unclear, and there is currently no effective specific treatment for Blau syndrome.

Objectives: To elucidate the mechanisms of autoinflammation in patients with Blau syndrome, we sought to clarify the relation between disease-associated mutant NOD2 and the inflammatory response in human samples.

Methods: Blau syndrome-specific induced pluripotent stem cell (iPSC) lines were established. The disease-associated NOD2 mutation of iPSCs was corrected by using a CRISPR-Cas9 system to precisely evaluate the in vitro phenotype of iPSC-derived cells. We also introduced the same NOD2 mutation into a control iPSC line. These isogenic iPSCs were then differentiated into monocytic cell lineages, and the statuses of nuclear factor κB pathway and proinflammatory cytokine secretion were investigated.

Results: IFN-γ acted as a priming signal through upregulation of NOD2. In iPSC-derived macrophages with mutant NOD2, IFN-γ treatment induced ligand-independent nuclear factor κB activation and proinflammatory cytokine production. RNA sequencing analysis revealed distinct transcriptional profiles of mutant macrophages both before and after IFN-γ treatment. Patient-derived macrophages demonstrated a similar IFN-γ-dependent inflammatory response.

Conclusions: Our data support the significance of ligand-independent autoinflammation in the pathophysiology of Blau syndrome. Our comprehensive isogenic disease-specific iPSC panel provides a useful platform for probing therapeutic and diagnostic clues for the treatment of patients with Blau syndrome.

Keywords: Blau syndrome; IFN-γ; disease-specific induced pluripotent stem cells; nuclear factor κB; nucleotide-binding oligomerization domain 2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arthritis / etiology*
  • Arthritis / metabolism*
  • Cell Lineage / genetics
  • Cytokines / metabolism
  • DNA Mutational Analysis
  • Exons
  • Gene Targeting
  • Genetic Loci
  • Humans
  • Induced Pluripotent Stem Cells / cytology
  • Induced Pluripotent Stem Cells / metabolism
  • Inflammation Mediators / metabolism
  • Interferon-gamma / genetics
  • Interferon-gamma / metabolism*
  • Ligands
  • Macrophages / immunology
  • Macrophages / metabolism*
  • Male
  • Mutation
  • NF-kappa B / metabolism
  • Nod2 Signaling Adaptor Protein / genetics
  • Phenotype
  • Pluripotent Stem Cells / cytology
  • Pluripotent Stem Cells / metabolism*
  • Sarcoidosis
  • Synovitis / etiology*
  • Synovitis / metabolism*
  • Uveitis / etiology*
  • Uveitis / metabolism*


  • Cytokines
  • Inflammation Mediators
  • Ligands
  • NF-kappa B
  • NOD2 protein, human
  • Nod2 Signaling Adaptor Protein
  • Interferon-gamma

Supplementary concepts

  • Blau syndrome