RNA interference targeting the ACE gene reduced blood pressure and improved myocardial remodelling in SHRs

Abstract

The purpose of the present study was to investigate the effects on blood pressure and myocardial hypertrophy in SHRs (spontaneously hypertensive rats) of RNAi (RNA interference) targeting ACE (angiotensin-converting enzyme). SHRs were treated with normal saline as vehicle controls, with Ad5-EGFP as vector controls, and with recombinant adenoviral vectors Ad5-EGFP-ACE-shRNA, carrying shRNA (small hairpin RNA) for ACE as ACE-RNAi. WKY (Wistar-Kyoto) rats were used as normotensive controls treated with normal saline. The systolic blood pressure of the caudal artery was recorded. Serum levels of ACE and AngII (angiotensin II) were determined using ELISA. ACE mRNA and protein levels were determined in aorta, myocardium, kidney and lung. On day 32 of the experiment, the heart was pathologically examined. The ratios of heart weight/body weight and left ventricular weight/body weight were calculated. The serum concentration of ACE was lower in ACE-RNAi rats (16.37+/-3.90 ng/ml) compared with vehicle controls and vector controls (48.26+/-1.50 ng/ml and 46.67+/-2.82 ng/ml respectively; both P<0.05), but comparable between ACE-RNAi rats and WKY rats (14.88+/-3.15 ng/ml; P>0.05). The serum concentration of AngII was also significantly lower in ACE-RNAi rats (18.24+/-3.69 pg/ml) compared with vehicle controls and vector controls (46.21+/-5.06 pg/ml and 44.93+/-4.12 pg/ml respectively; both P<0.05), but comparable between ACE-RNAi rats and WKY rats (16.06+/-3.11 pg/ml; P>0.05). The expression of ACE mRNA and ACE protein were significantly reduced in the myocardium, aorta, kidney and lung in ACE-RNAi rats compared with that in vehicle controls and in vector controls (all P<0.05). ACE-RNAi treatment resulted in a reduction in systolic blood pressure by 22+/-3 mmHg and the ACE-RNAi-induced reduction lasted for more than 14 days. In contrast, blood pressure was continuously increased in the vehicle controls as well as in the vector controls. The ratios of heart weight/body weight and left ventricular weight/body weight were significantly lower in ACE-RNAi rats (3.12+/-0.23 mg/g and 2.24+/-0.19 mg/g) compared with the vehicle controls (4.29+/-0.24 mg/g and 3.21+/-0.13 mg/g; P<0.05) and the vector controls (4.43+/-0.19 mg/g and 3.13+/-0.12 mg/g; P<0.05). The conclusion of the present study is that ACE-silencing had significant antihypertensive effects and reversed hypertensive-induced cardiac hypertrophy in SHRs, and therefore RNAi might be a new strategy in controlling hypertension.

Brain Renin-Angiotensin System: Fetal Epigenetic Programming by Maternal Protein Restriction During Pregnancy

“…8 Transgenic mice with small interfering RNA (siRNA)mediated alterations of the various components of the RAS demonstrated changes in blood pressure, suggesting a causal role of this system in the pathogenesis of hypertension. [9][10][11] Epidemiologic studies in humans, and studies in experimental animals, have demonstrated that antenatal maternal protein deprivation can result in the development of hypertension, stroke, depression, schizophrenia, obesity, diabetes, and other conditions in the offspring. 6,[12][13][14][15] Furthermore, RAS alterations have been shown to be involved in fetal programming as a consequence of maternal low protein diet (MLPD) during pregnancy.…”

Therapeutic implications of small interfering RNA in cardiovascular diseases

“…Thus, it was observed that E1,2,3 splice variant was responsible for majority of functional AT 1 receptor expression in RASMC and siRNA can be used to silence rAT 1a receptor mRNA in a splice variant-specific manner in RASMC. In another study, ACE silencing has been reported to exert significant anti-hypertensive effects in SHRs [25]. In this study, He et al [25] treated SHRs with recombinant adenoviral vectors Ad5-EGFP-ACE-shRNA (EGFP is enhanced green fluorescent protein).…”

“…In this study, He et al. treated SHRs with recombinant adenoviral vectors Ad5‐EGFP‐ACE‐shRNA (EGFP is enhanced green fluorescent protein). A significant reduction in SBP along with decreased ACE mRNA expression in the myocardium, aorta, kidney, and lung was observed in ACE RNAi SHRs.…”

Nanoparticle-mediated RNA interference of angiotensinogen decreases blood pressure and improves myocardial remodeling in spontaneously hypertensive rats

“…However, most AT1R-knockdown studies are performed in vitro, while only a few studied have used in vivo animal models (23,24). In the present study, knockdown of AT1R (25) and angiotensin-converting enzyme (ACE) (26) were investigated in SHR, as AT1R and ACE are associated with the function of Nanoparticle-mediated RNA interference of angiotensinogen decreases blood pressure and improves myocardial remodeling in spontaneously hypertensive rats angiotensin II (AngII) in hypertension. Of note, AGT gene expression in SHR has rarely been studied (27).…”