URAT1 inhibition by ALPK1 is associated with uric acid homeostasis.

Objective. The aim of this study was to identify a protein for urate transporter 1 (URAT1) regulation. Methods. The clinical dataset consisted of 492 case-control samples of Han Chinese (104 gout and 388 controls). Three alpha kinase 1 (ALPK1) and SLC22A12 loci associated with high gout risk and uric acid levels were genotyped. The overexpression of ALPK1 on URAT1 protein expression was evaluated in vivo in hALPKI transgenic mice. The in vitro protein levels of ALPK1 and URAT1 in ALPK1 small interfering RNA-transfected human kidney-2 cells with MSU crystal stimulation were examined. Results. ALPK1, which is a single nucleotide polymorphism (SNP) of rs11726117 (M861T; T), reduced the risk of gout via the SLC22A12 gene SNPs rs3825016 and rs475688, as compared with the subject of ALPK1 rs11726117 (C) allele {rs11726117 [CT + TT] vs rs3825016, odds ratio [OR] 0.39 [95% confidence interval (CI) 0.23, 0.67]; rs11726117 [CT + TT] vs rs475688, OR 0.39 [95% CI 0.23, 0.67]}. ALPK1-over- expressed mice demonstrated lower levels of URAT1 protein (P = 0.0045). Mouse endogenous ALPK1 proteins were detected in renal proximal tubule cells. MSU crystals inhibited URAT1 expressions through an upregulation of ALPK1 in human kidney-2 cells. Conclusion. Elevated ALPK1 expression decreased URAT1 expression. ALPK1 might prevent the impact of urate reuptake via SLC22A12 and appeared to be negatively associated with gout. ALPK1 is a potential repressor of URAT1 protein expression. [ABSTRACT FROM AUTHOR]