Urate-induced epigenetic modifications in myeloid cells

Area of Science:

• Immunology
• Epigenetics
• Metabolic Disorders

Background:

• Hyperuricemia, a metabolic condition, is central to gout pathogenesis.
• Urate exposure increases the inflammatory potential of human monocytes, specifically their capacity to produce and release IL-1β.

Purpose of the Study:

• To investigate the epigenetic mechanisms underlying urate-mediated hyper-responsiveness in monocytes.
• To assess the impact of urate on histone modifications and DNA methylation in the context of hyperuricemia.

Main Methods:

• Human peripheral blood mononuclear cells or monocytes were pre-treated with urate and stimulated with LPS, with or without monosodium urate (MSU) crystals.
• Histone epigenetic marks (H3K4me3, H3K27ac) were assessed by sequencing immunoprecipitated chromatin, and DNA methylation by methylation array in human participants.
• In vivo studies involved MSU crystal injections in mice following uricase inhibition and urate administration.

Main Results:

• High urate concentrations amplified inflammatory responses in vitro and in vivo; broad-spectrum methylation inhibitors counteracted this effect.
• Urate-primed monocytes exhibited distinct patterns of H3K4me3 and H3K27ac compared to controls.
• Differential DNA methylation was observed in genes related to inflammatory cytokine signaling (e.g., HLA-G, IFITM3, PRKAB2) in individuals with hyperuricemia versus normouricemia.

Conclusions:

• Urate significantly alters the epigenetic landscape of human monocytes and whole blood in individuals with hyperuricemia.
• Both histone modifications and DNA methylation patterns are influenced by urate exposure.
• Epigenetic modifications in myeloid cells represent a potential therapeutic avenue for gout, pending further validation.