DUSP1 Mitigates MSU-Induced Immune Response in Gouty Arthritis Reinforcing Autophagy

Persistent hyperuricemia can lead to the generation and deposition of monosodium urate (MSU) crystals. This can trigger gouty arthritis (GA), which in turn induces inflammation. Activation of the Nod-like receptor pyrin domain containing 3 (NLRP3) inflammasome plays a critical role in the onset and progression of GA. Autophagy may have a dual effect on GA with regard to the NLRP3 inflammasome. Therefore, the present study aimed to gain a deeper comprehension of the interaction between autophagy and NLRP3 inflammasome activation is imperative for developing more efficacious treatments for GA.

Peripheral blood monocytes (PBMCs) were first isolated from GA patients and healthy controls and underwent bulk RNA sequencing analysis. Overexpression and knockdown of dual specificity phosphatase 1 (DUSP1) was performed in THP-1 monocytes to investigate its role in the immune response and mitochondrial damage. The luciferase assay and Western blot analysis were used to study the interaction between autophagy and NLRP3 inflammasome activation.

Bulk RNA sequencing analysis showed significant upregulation of DUSP1 expression in PBMCs from GA patients compared to healthy controls. This result was subsequently verified by reverse transcription quantitative polymerase chain reaction (RT-qPCR). DUSP1 expression in human THP-1 monocytes was also shown to increase after MSU treatment. Downregulation of DUSP1 expression increased the secretion of inflammatory cytokines after MSU treatment, whereas the overexpression of DUSP1 decreased the secretion levels. Lipopolysaccharides (LPS) combined with adenosine-triphosphate (ATP) led to mitochondrial damage, which was rescued by overexpressing DUSP1. DUSP1 overexpression further increased the level of autophagy following MSU treatment, whereas downregulation of DUSP1 decreased autophagy. Treatment with the autophagy inhibitor 3-Methyladenine (3-MA) restored inflammatory cytokine secretion levels in the DUSP1 overexpression group. MSU caused pronounced pathological ankle swelling in vivo. However, DUSP1 overexpression significantly mitigated this phenotype, accompanied by significant downregulation of inflammatory cytokine secretion levels in the joint tissues.

This study revealed a novel function and mechanism for DUSP1 in promoting autophagy to mitigate the MSU-induced immune response in GA. This finding suggests potential diagnostic biomarkers and anti-inflammatory targets for more effective GA therapy.