Regulation of SOCS3-STAT3 in urate-induced cytokine production in human myeloid cells

Joint Bone Spine. 2024 May;91(3):105698. doi: 10.1016/j.jbspin.2024.105698. Epub 2024 Feb 1.

Abstract

Objective: Hyperuricaemia is necessary for gout. High urate concentrations have been linked to inflammation in mononuclear cells. Here, we explore the role of the suppressor of cytokine signaling 3 (SOCS3) in urate-induced inflammation.

Methods: Peripheral blood mononuclear cells (PBMCs) from gout patients, hyperuricemic and normouricemic individuals were cultured for 24h with varying concentrations of soluble urate, followed by 24h restimulation with lipopolysaccharides (LPS)±monosodium urate (MSU) crystals. Transcriptomic profiling was performed using RNA-Sequencing. DNA methylation was assessed using Illumina Infinium® MethylationEPIC BeadChip system (EPIC array). Phosphorylation of signal transducer and activator of transcription 3 (STAT3) was determined by flow cytometry. Cytokine responses were also assessed in PBMCs from patients with JAK2 V617F tyrosine kinase mutation.

Results: PBMCs pre-treated with urate produced more interleukin-1beta (IL-1β) and interleukin-6 (IL-6) and less interleukin-1 receptor anatagonist (IL-1Ra) after LPS simulation. In vitro, urate treatment enhanced SOCS3 expression in control monocytes but no DNA methylation changes were observed at the SOCS3 gene. A dose-dependent reduction in phosphorylated STAT3 concomitant with a decrease in IL-1Ra was observed with increasing concentrations of urate. PBMCs with constitutively activated STAT3 (JAK2 V617F mutation) could not be primed by urate.

Conclusion: In vitro, urate exposure increased SOCS3 expression, while urate priming, and subsequent stimulation resulted in decreased STAT3 phosphorylation and IL-1Ra production. There was no evidence that DNA methylation constitutes a regulatory mechanism of SOCS3. Elevated SOCS3 and reduced pSTAT3 could play a role in urate-induced hyperinflammation since urate priming had no effect in PBMCs from patients with constitutively activated STAT3.

Keywords: DNA methylation; Gout; Hyperuricemia; Inflammation; SOCS3; STAT3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Cytokines* / metabolism
  • DNA Methylation
  • Female
  • Gout* / genetics
  • Gout* / metabolism
  • Humans
  • Hyperuricemia / metabolism
  • Janus Kinase 2 / metabolism
  • Leukocytes, Mononuclear / drug effects
  • Leukocytes, Mononuclear / metabolism
  • Male
  • Middle Aged
  • Myeloid Cells / drug effects
  • Myeloid Cells / metabolism
  • STAT3 Transcription Factor* / metabolism
  • Suppressor of Cytokine Signaling 3 Protein* / genetics
  • Suppressor of Cytokine Signaling 3 Protein* / metabolism
  • Uric Acid* / pharmacology

Substances

  • Suppressor of Cytokine Signaling 3 Protein
  • Uric Acid
  • STAT3 Transcription Factor
  • SOCS3 protein, human
  • Cytokines
  • STAT3 protein, human
  • Janus Kinase 2