COUNTERACTING ANGIOTENSINOGEN SMALL INTERFERING RNA-MEDIATED ANTIHYPERTENSIVE EFFECTS WITH REVERSIR
Edwyn Cruz López, Dien Ye, Richard Van Veghel, Ingrid M. Garrelds, Anne Kasper, Kelly Wassarman, Ho -Chou Tu, Ivan Zlatev, A. H. Jan DanserObjective:
Administering small interfering RNA (siRNA) targeting liver angiotensinogen (AGT) effectively depletes circulating AGT, leading to a sustained blood pressure reduction for up to six months post-single injection. However, certain situations may require a rapid increase in angiotensin levels. The REVERSIR (reverse siRNA silencing, RVR) technology is being studied as a potential approach to counteract AGT-siRNA effects.
Design and method:
Spontaneously hypertensive rats (SHR) underwent a 3-week AGT-siRNA treatment, followed by AGT-RVR doses at 1, 10, or 20 mg/kg. After a week of AGT-RVR, a re-dose of AGT-siRNA assessed its post-AGR-RVR effectiveness. Additionally, the impact of AGT-RVR with a 3-week valsartan treatment (4 mg/kg per day) was examined. Arterial pressure was measured via radiotelemetry, circulating AGT, and renin by enzyme-kinetic assays, and liver AGT mRNA levels by quantitative PCR.
Results:
: Baseline mean arterial pressure (MAP) was 144±1 mm Hg. AGT-siRNA reduced MAP by ∼16 mm Hg and circulating AGT by >95.9%, with a 25-fold increase in circulating renin. All AGT-RVR doses restored MAP to baseline within a week. Notably, 10 and 20 mg/kg fully restored circulating AGT and renin to baseline, while 1 mg/kg allowed ∼50% AGT restoration with renin above baseline. Liver AGT mRNA changes mirrored circulating AGT alterations. A second AGT-siRNA dose, on top of 1 mg/kg AGT-RVR, replicated the initial dose’s MAP effect. On top of 10 mg/kg AGT-RVR, the second dose resulted in ∼50% of the first dose’s MAP effect. Valsartan, like AGT-siRNA, reduced MAP similarly, inducing a 30-fold renin increase and 39.6% circulating AGT reduction. Adding AGT-RVR to valsartan did not alter this outcome.
Conclusions:
AGT-RVR dose-dependently reversed AGT-siRNA-induced AGT reduction, normalizing MAP. Notably, MAP normalization persisted with partially recovered AGT levels (∼50%), likely due to upregulated renin maintaining normal angiotensin generation. AGT-RVR had no impact on valsartan-induced AGT reduction. Post-AGR-RVR, a second AGT-siRNA dose effectively lowered MAP to the same extent as the initial dose. In summary, AGT-RVR is a highly selective tool for AGT and BP restoration in SHR. These findings support further evaluation of the RVR platform to counteract siRNA-mediated effects.