The guanine nucleotide exchange factor Rin-like is a repressor for renal uric acid excretion in human and mouse

The prevalence of hyperuricemia (HUA) is increasing annually and now affects ∼14% of the population. Uric acid (UA) is the end product of purine metabolism in humans. Either increased production or reduced excretion of UA can induce HUA. Here, we identified RAS and RAB interactor-like (RINL) as a regulator of renal UA excretion and conducted a screen for compounds capable of lowering serum UA concentrations. We found that the human RINL (hRINL) Pro¹³⁹→Ser (P139S) mutation was pathogenic for HUA in a familial pedigree. As a guanine nucleotide exchange factor, RINL activated RAB5C in renal tubular epithelial cells. Activated RAB5C promoted the endocytosis and lysosomal degradation of the UA transporter ATP-binding cassette subfamily G member 2, thereby inhibiting renal UA excretion and contributing to the development of HUA. The hRINL (P139S) mutation inhibited proteasome-mediated degradation of hRINL in renal tubular epithelial cells, causing its accumulation, and the homologous mouse RINL (mRINL) Pro¹⁴⁰→Ser (P140S) mutation up-regulated mRINL in mouse kidneys, indicating a gain-of-function mutation. We screened a library of 1500 natural products for RINL inhibitors and, after experimental validation, found that tetrahydrocurcumin bound to RINL and promoted its degradation, thereby ameliorating HUA induced by potassium oxonate treatment, uricase knockout, or secondary to severe malaria and chronic kidney disease in mice. These findings establish RINL as a repressor of UA excretion in both humans and mice and suggest that targeted degradation of RINL represents a promising strategy for HUA treatment.