Volume 83, Issue 4, Pages 733-740 (April 2013) Common genetic variants of the human uromodulin gene regulate transcription and predict plasma uric acid levels  Jia Han, Ying Liu, Fangwen Rao, Caroline M. Nievergelt, Daniel T. O'Connor, Xingyu Wang, Lisheng Liu, Dingfang Bu, Yu Liang, Fang Wang, Luxia Zhang, Hong Zhang, Yuqing Chen, Haiyan Wang  Kidney International  Volume 83, Issue 4, Pages 733-740 (April 2013) DOI: 10.1038/ki.2012.449 Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 1 UMOD (uromodulin) promoter common genetic variation: Effect on urine uric acid excretion in a community based cohort of the Chinese population. Urine uric acid excretion was measured in spot (untimed) urine samples from year 2008. Promoter rs6497476 results indicated that C allele carriers had lower urinary uric acid-to-creatinine ratios than T/T homozygotes. Kidney International 2013 83, 733-740DOI: (10.1038/ki.2012.449) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 2 UMOD (uromodulin) haplotype ATTGGCA: Effect on urinary UMOD excretion in a community-based cohort of Chinese population. Haplotype (HAP) homozygosities were confirmed by PLINK (URL: http://pngu.mgh.harvard.edu∼purcell/plink/).43 Urinary UMOD-to-creatinine ratio was presented as μg/mg. The common long haplotype ATTGGCA associated with urinary UMOD-to-creatinine ratio. Kidney International 2013 83, 733-740DOI: (10.1038/ki.2012.449) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 3 Uric acid trait heritability in twin pairs. Heritability (h2) of plasma uric acid and uric acid excretion, as well as estimated glomerular filtration rate (eGFR). h2, the fraction of trait variance accounted for by genetic variance (h2=VG/VP) was established by study of variance components in California 173 twin pairs (346 individuals). Plasma uric acid is in μmol/l, while urinary uric acid to creatinine ratio is in μmol/mmol, and eGFR was calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) algorithm (normalized to ml/min per 1.73m2). Kidney International 2013 83, 733-740DOI: (10.1038/ki.2012.449) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 4 UMOD (uromodulin) promoter haplotype/luciferase reporter functional studies. Transfection results for human UMOD promoter haplotype/luciferase reporters are shown in human embryonic kidney (HEK-293) cells as well as in mouse inner medullary collecting duct (mIMCD-3). Results are expressed as the ratio of firefly/Renilla luciferase activity. As a negative control, the ratio of firefly/Renilla luciferase activities for the promoter-less luciferase reporter vector (empty vector pGL3-Basic) co-transfected with transfection efficiency control plasmid Renilla plasmid (pTK-RL) was 0.002±0.001 for HEK-293 cells and 8.44 × 10-5±1.84 × 10-6 for mIMCD-3. The absolute firefly luminescence for UMOD haplotype ATT was 22826±1739RLU/s in HEK293 cells; 235±28RLU/s in mIMCD-3. In all, 50μl from each 500μl cell lysate were used for luciferase assay. Each experiment was performed in triplicate, and such experiments were repeated at least three times. Statistical significance refers to the haplotype effects. Results are compared by analysis of variance followed by post-hoc LSD. (a) *P=0.006, **P=0.002, ***P<0.001 when compared with HAP ATT. (b) *P=0.002, **P=0.023, #P=0.046, ##P=0.035 when compared with HAP ATT. Kidney International 2013 83, 733-740DOI: (10.1038/ki.2012.449) Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 5 Uromodulin (UMOD, Tamm–Horsfall protein): working hypothesis for transcriptional and pathophysiological consequences of common genetic variants in the promoter. mTAL/DCT, medullary thick ascending limb/distal convoluted tubule; SNP, single nucleotide polymorphism. Kidney International 2013 83, 733-740DOI: (10.1038/ki.2012.449) Copyright © 2013 International Society of Nephrology Terms and Conditions