Expression of Nedd4L gene in Brain of Dahl Rats

Abstract

ENaC subunits are present in choroids plexus (CP) and brain cardiovascular nuclei. Nedd4L, an ubiquitin protein ligase, binds to PY motifs of ENaC subunits and decreases ENaC expression and activity at the cell surface. The aim of this study was to assess brain Nedd4L transcription levels as a function of dietary salt in different brain areas in Wistar (W), Dahl S and R rats. WR (5–6/group) were placed on low (0.03%), regular (0.3%), and high (8%) salt diets for 4 weeks, Dahl rats were placed on regular and high salt diets for 2 or 4 weeks. Nedd4L expression was assessed by real-time RT-PCR. Screening of Need4L coding region was done by PCR-Sequencing. In WR, salt intake has no effect on Nedd4L mRNA levels in CP or SON. In Dahl rats, Nedd4L mRNA abundance is elevated in SON of S versus R rats on regular salt. High salt didn’t induce any further increase in Nedd4LmRNA. Salt intake or strain had no effect on Nedd4L expression in CP and PVN. No difference was found in Nedd4L coding regions between S, R rats and WR. We conclude that compared to R rats, higher mRNA expression levels of Nedd4L in SON of S indicates a tissue specific abnormal regulation of this gene in S rats which may contribute to salt sensitive hypertension. This project is supported by HSFO and CIHR.