High salt diet elevates the mean arterial pressure of SLC14α1 gene depletion mice

Aims: Urea transporter B (UTB) is encoded by the SLC14α1 gene, and exerts its activity in the choroid plexus (CP) by regulating [Na⁺] in the cerebrospinal fluid (CSF) and maintaining normal blood pressure in mice fed on high salt diet. The aim of this study is to investigate the effect of high salt diet on the mean arterial pressure (MAP) in SLC14α1 depletion mice and its possible molecular mechanism.

Main methods: Adult male mice were divided into four groups: 1) UTB^+/+(wild type) mice + normal salt diet (0.3% NaCl, NS); 2) UTB^+/+ mice + high salt diet (8% NaCl, HS); 3) UTB^-/- (SLC14α1 knockout) mice + NS; 4) UTB^-/- mice + HS, each group consisted of 6 mice. The MAP of mice was measured by non-invasive detection method after HS diet for 4 weeks, followed by euthanization for brain and blood collection.

Key findings: HS significantly elevated the MAP and CSF [Na⁺] in UTB^-/- mice in comparison with wild type mice; however, NS didn't alter the MAP and CSF [Na⁺] in either wild type mice or UTB^-/- mice. HS also induced the expression of ENaC-α and α₁-Na⁺-K⁺-ATPase in UTB^-/- mice as confirmed by RT-PCR and Western blot.

Significance: These results suggest that the depletion of SLC14α1 gene in mice may contribute to the HS-induced abnormality of sodium transportation in the CSF, and lead to the elevation of MAP, which eventually promote the development of salt-sensitive hypertension.