Artificial microRNA interference targeting AT(1a) receptors in paraventricular nucleus attenuates hypertension in rats.

Excessive sympathetic activity has a crucial role in the initiation and progression of chronic structural alterations in the heart and vessels associated with hypertension. Angiotensin II type 1a receptors (AT(1a)R) in paraventricular nucleus (PVN) are involved in sympathetic overdrive and hypertension. The present study was designed to investigate the cardiovascular beneficial effects of the AT(1a)R gene silence in the PVN in hypertension. The PVN microinjection of recombinant adenoviral vectors expressing either artificial microRNA (amiRNA) targeting AT(1a) receptors (Ad-miR-AT(1a)) or control microRNA (Ad-miR-Con) were carried out in spontaneously hypertensive rats (SHR) and normotensive Wistar rats. The vectors were labels with green fluorescent protein (GFP). The successful amiRNA interference was confirmed by the AT(1) receptors reduction and the GFP expression in the PVN. Significant depressor effects were observed from day 5 to day 20 after Ad-miR-AT(1a) treatment in SHR. Ad-miR-AT(1a) treatment decreased the ratio of left ventricular weight to body weight, cross-sectional areas of myocytes, myocardial fibrosis, media thickness, and the media/lumen ratio of the aorta and the mesenteric artery in SHR. The amiRNA interference reduced the basal sympathetic activity, cardiac sympathetic afferent reflex, plasma norepinephrine and plasma angiotensin II in SHR. These results indicate that amiRNA interference targeting AT(1a)R in the PVN decreases arterial blood pressure, blunts sympathetic activity and improves myocardial and vascular remodeling in SHR.