Long non-coding RNA HOTAIR knockdown alleviates gouty arthritis through miR-20b upregulation and NLRP3 downregulation

This study aimed to determine the mechanism underlying the regulation of gout by the HOX transcript antisense RNA (HOTAIR) long non-coding RNA (lncRNA). The expression levels of HOTAIR, miR-20b, and Nlrp3 were estimated by qRT-PCR and western blotting. The methylation level of HOTAIR was detected by methylation-specific PCR. The recruitment of DNA methyltransferase 1 (DNMT1) to the lncRNA HOTAIR promoter was confirmed by a ChIP assay. RNA immunoprecipitation and RNA pull-down assays were used to confirm the interaction between HOTAIR and miR-20b. LncRNA HOTAIR and Nlrp3 expression was upregulated, and that of miR-20b was downregulated in synovial fluid mononuclear cells (SFMCs) collected from patients with gouty arthritis and monosodium urate (MSU)-stimulated THP-1 cells. Interleukin (IL)-1β level increased substantially upon stimulation by MSU crystals. The methylation percentage of HOTAIR was reduced in SFMCs from patients with gouty arthritis and MSU-stimulated THP-1 cells. DNMT1 expression was downregulated in MSU-stimulated THP-1 cells, and DNMT1 knockdown increased lncRNA HOTAIR expression. In addition, the interaction of HOTAIR with miR-20b was confirmed. HOTAIR knockdown suppressed Nlrp3 expression and the secretion of inflammatory cytokines via miR-20b regulation. Finally, in vivo experiments showed that HOTAIR knockdown alleviated ankle swelling in a mouse model of gouty arthritis. These findings suggest that lncRNA HOTAIR knockdown suppresses inflammatory cytokine secretion by upregulating miR-20b and downregulating NLRP3, thereby alleviating ankle swelling in gouty arthritis.