Validation of uromodulin as a candidate gene for human essential hypertension

Lesley A. Graham, Sandosh Padmanabhan, Niall J. Fraser, Satish Kumar, James M. Bates, Hajamohideen S. Raffi, Paul Welsh, Wendy Beattie, Shoujin Hao, Sabine Leh, Michael Hultstrom, Nicholas R. Ferreri, Anna F. Dominiczak, Delyth Graham, Martin W. Mcbride

    Research output: Contribution to journalArticlepeer-review

    104 Citations (Scopus)

    Abstract

    A recent genome-wide association study identified a locus on chromosome 16 in the promoter region of the uromodulin (UMOD) gene that is associated with hypertension. Here, we examined the hypertension signal with functional studies in Umod knockout (KO) mice. Systolic blood pressure was significantly lower in KO versus wild-type (WT) mice under basal conditions (KO: 116.6±0.3 mm Hg versus WT: 136.2±0.4 mm Hg; P<0.0001). Administration of 2% NaCl did not alter systolic blood pressure in KO mice, whereas it increased in WT mice by ≈33%, P<0.001. The average 24-hour urinary sodium excretion in the KO was greater than that of WT mice (P<0.001). Chronic renal function curves demonstrate a leftward shift in KO mice, suggesting that the relationship between UMOD and blood pressure is affected by sodium. Creatinine clearance was increased during salt loading with 2% NaCl in the KO mice, leading to augmented filtered Na excretion and further Na loss. The difference in sodium uptake that exists between WT and KO strains was explored at the molecular level. Urinary tumor necrosis factor-α levels were significantly higher in KO mice compared with WT mice (P<0.0001). Stimulation of primary thick ascending limb of the loop of Henle cells with exogenous tumor necrosis factor-α caused a reduction in NKCC2A expression (P<0.001) with a concurrent rise in the levels of UMOD mRNA (P<0.001). Collectively, we demonstrate that UMOD regulates sodium uptake in the thick ascending limb of the loop of Henle by modulating the effect of tumor necrosis factor-α on NKCC2A expression, making UMOD an important determinant of blood pressure control.

    Original languageEnglish
    Pages (from-to)551-558
    Number of pages8
    JournalHypertension
    Volume63
    Issue number3
    DOIs
    Publication statusPublished - 1 Mar 2014

    Keywords

    • hypertension
    • mice
    • mice, knockout
    • Umod protein, mouse
    • uromodulin

    ASJC Scopus subject areas

    • Internal Medicine

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