Reduced expression of FXYD domain containing ion transport regulator 5 in association with hypertension

Experimental evidence indicates that hypertension is a multifactorial disorder and that the products of several genes may contribute to its development. The aim of this study was to investigate the expression of hypertension-related genes in spontaneous hypertensive rats (SHRs). A microarray screening for hypertension-related genes was conducted in SHRs and Wistar-Kyoto (WKY) rats using total-RNA extracted from second-order mesenteric arteries and kidneys. The FXYD5 mRNA expression in vascular smooth muscle cells (VSMCs) was silenced by RNA interference (RNAi). Meanwhile, the FXYD5 mRNA overexpression in renal tubular epithelial cells (RTECs) was induced by the recombinant plasmid pcDNA3.1(+)-FXYD5. The expression of FXYD5 mRNA was found to be 14.8-fold lower in SHR rats compared to that in WKY rats (P<0.01). The levels of FXYD5 mRNA expression were the highest in kidneys of SHR 13-week-old rats when the blood pressure reached the highest levels. The down-regulated FXYD5 mRNA expression inhibited the migration of smooth muscle cells (P<0.01) and cell membrane Na⁺-K⁺-ATPase activity (P<0.01). Up-regulated FXYD5 mRNA expression enhanced the renal tubular epithelial cell membrane Na⁺-K⁺-ATPase activity (P<0.05) and cell proliferation (P<0.05). FXYD5 is related to the migration of smooth muscle cells and cell membrane Na⁺-K⁺-ATPase activity in rodents. The results of the present study suggest that FXYD5 may have profound impact on the regulation of blood pressure, and that this gene may be a potential target for anti-hypertensive therapy.