Gene-environment interaction modifies the association between hyperinsulinemia and serum urate levels through SLC22A12
Wataru Fujii, … , Yuta Kochi, Shigeru Shibata
Wataru Fujii, … , Yuta Kochi, Shigeru Shibata
Published March 18, 2025
Citation Information: J Clin Invest. 2025;135(10):e186633. https://doi.org/10.1172/JCI186633.
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Clinical Research and Public Health Genetics Metabolism Nephrology

Gene-environment interaction modifies the association between hyperinsulinemia and serum urate levels through SLC22A12

Abstract

BACKGROUND Hyperinsulinemia and insulin resistance often accompany elevated serum urate levels (hyperuricemia), a highly heritable condition that triggers gout; however, the underlying mechanisms are unclear.METHODS We evaluated the association between the index of hyperinsulinemia and the fractional excretion of urate (FEUA) in 162 outpatients. The underlying mechanisms were investigated through single-cell data analysis and kinase screening combined with cell culture experiments. In 377,358 participants of the UK Biobank (UKBB), we analyzed serum urate, hyperinsulinemia, and salt intake. We also examined gene-environment interactions using single nucleotide variants in SLC22A12, which encodes urate transporter 1 (URAT1).RESULTS The index of hyperinsulinemia was inversely associated with FEUA independently of other covariates. Mechanistically, URAT1 cell-surface abundance and urate transport activity were regulated by URAT1-Thr408 phosphorylation, which was stimulated by hyperinsulinemia via AKT. Kinase screening and single-cell data analysis revealed that serum and glucocorticoid-regulated kinase 1 (SGK1), induced by high salt, activated the same pathway, increasing URAT1. Arg405 was essential for these kinases to phosphorylate URAT1-Thr408. In UKBB participants, hyperinsulinemia and high salt intake were independently associated with increased serum urate levels. We found that SLC22A12 expression quantitative trait locus (eQTL) rs475688 synergistically enhanced the positive association between serum urate and hyperinsulinemia.CONCLUSION URAT1 mediates the association between hyperinsulinemia and hyperuricemia. Our data provide evidence for the role of gene-environment interactions in determining serum urate levels, paving the way for personalized management of hyperuricemia.FUNDING ACRO Research Grants of Teikyo University; Japan Society for the Promotion of Science; the Japanese Society of Gout and Uric & Nucleic Acids; Fuji Yakuhin; Nanken-Kyoten; Medical Research Center Initiative for High Depth Omics.

Authors

Wataru Fujii, Osamu Yamazaki, Daigoro Hirohama, Ken Kaseda, Emiko Kuribayashi-Okuma, Motonori Tsuji, Makoto Hosoyamada, Yuta Kochi, Shigeru Shibata

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Figure 2

URAT1-T408 is phosphorylated in human kidney and mediates insulin-induced URAT1 trafficking to the cell surface.

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URAT1-T408 is phosphorylated in human kidney and mediates insulin-induce...
(A) Antibody against hURAT1 phosphorylated at T408 (hURAT1T408-P) was incubated with hURAT1 peptide phosphorylated at T408 and nonphosphorylated hURAT1 peptide spotted on a membrane, followed by incubation with peroxidase-conjugated anti-rabbit antibody. Signals were visualized by ECL. (B) HEK cells expressing Flag-hURAT1WT were incubated with calyculin A. Cells were lysed and purified by Flag-IP. Phospho-hURAT1 (arrow) and total hURAT1 levels were detected by Western blotting. (C) HEK cells expressing hURAT1WT, hURAT1T408A, and hURAT1T350A/T408A were incubated with 50 nM of calyculin A, lysed, and purified by Flag-IP. Phosphorylated and total hURAT1 levels were detected by Western blotting. Arrows indicate hURAT1T408-P. (D) Endogenous hURAT1 was purified from lysates of human proximal tubule cell line HK-2 cells by IP using URAT1 antibody, incubated with and without PNGase F, followed by Western blotting using phospho-hURAT1 and hURAT1 antibodies. (E) Detection of total and phosphorylated forms of hURAT1 in the human kidney by Western blotting. (F) Immunofluorescence photomicrographs of total hURAT1 and phospho-hURAT1 in adjacent sections of the human kidney. Scale bar: 50 μm. (G) HEK cells expressing hURAT1WT were incubated in the absence or presence of insulin at 100 nM. Lysates were analyzed by the indicated antibodies. (H) HEK cells expressing hURAT1WT were incubated with insulin and lysates were purified by IP, followed by Western blot analysis using phospho-hURAT1 antibody. Arrow indicates hURAT1T408-P. The bottom panel shows the total hURAT1. (I and J) WT (I) and nonphosphorylatable T408A (J) hURAT1 were expressed in HEK cells and were incubated with insulin. Cell-surface levels of hURAT1 were determined by cell-surface biotinylation assay. Bar graphs show the results of quantitation (n = 6). Data are represented as mean ± SEM. (I and J) Unpaired t test. ***P < 0.001.