Targeted knockdown of hepatic XDH via GalNAc-siRNA alleviates hyperuricaemia and renal injury in UOX-/- mice.

Hyperuricaemia is a metabolic disorder characterized by elevated serum urate levels. Uric acid production primarily results from purine metabolism, with xanthine dehydrogenase (XDH) serving as a key enzyme determining uric acid synthesis. RNA interference technology has emerged as a powerful tool for gene regulation in recent years. Specifically, N-acetylgalactosamine (GalNAc)-modified small interfering RNA (siRNA), hereafter referred to as GalNAc-siRNA, can selectively deliver siRNAs to hepatocytes, achieving highly efficient knockdown of liver target genes. This study employed GalNAc-siRNA to specifically knock down hepatic XDH expression of hyperuricaemia mice, offering a promising therapeutic strategy. Initially, AML12 cells were used to identify siRNAs that knocked down XDH expression. A hyperuricaemia cell model, established by supplementing culture medium of AML12 cells with xanthine, was used to validate the effects of an XDH-targeting siRNA on uric acid synthesis. Moreover, following the subcutaneous injection of XDH-targeting GalNAc-siRNA (GalNAc-siXDH) in mice, XDH expression levels across various organs were measured to verify liver-specific knockdown. Additionally, the safety of GalNAc-siXDH was evaluated through serum biochemistry and histopathological analysis of major organs. Finally, the therapeutic effects of GalNAc-siXDH were evaluated in the urate oxidase knockout (UOX-/-) hyperuricaemia mouse model. Our results demonstrated that GalNAc-siXDH can reduce serum urate levels, and alleviate renal damage including inflammation and fibrosis, indicating that GalNAc-siXDH is a potential therapeutic candidate for the treatment of hyperuricaemia.