Targeting of hepatic angiotensinogen using chemically modified siRNAs results in significant and sustained blood pressure lowering in a rat model of hypertension

Olearczyk, J; Gao, Sheng; Eybye, Marianne; Yendluri, Satyasri; Andrews, Lori; Bartz, Steven R.; Cully, Doris; Tadin‐Strapps, Marija

doi:10.1038/hr.2013.155

Cited by 39 publications

(29 citation statements)

References 48 publications

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“…Ã P < 0.05, ÃÃ P < 0.01, ÃÃÃ P < 0.001, ÃÃÃÃ P < 0.0001 compared with nt control. platform has generally been deemed as highly selective [23,24,32,33], it is unknown at this point whether the FXII siRNA elicited off-target gene silencing on other unmeasured coagulation components or indirect modulators of the hemostatic system, and if yes, whether that would account for the unexpected findings on PT or high tissue factor-TGA. Interpretation of our FXII titration results thus carries limitations.…”

Section: Discussionmentioning

confidence: 97%

Factor XII full and partial null in rat confers robust antithrombotic efficacy with no bleeding

Cai¹,

Wu²,

Shin

et al. 2015

Blood Coagulation &Amp; Fibrinolysis

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This report aims at exploring quantitatively the relationship between FXII inhibition and thromboprotection. FXII full and partial null in rats were established via zinc finger nuclease-mediated knockout and siRNA-mediated knockdown, respectively. The rats were subsequently characterized in thrombosis and hemostasis models. Knockout rats exhibited complete thromboprotection in both the arteriovenous shunt model (∼100% clot weight reduction) and the FeCl3-induced arterial thrombosis model (no reduction in blood flow), without any increase in cuticle bleeding time compared with wild-type control rats. Ex-vivo aPTT and the ellagic acid-triggered thrombin generation assay (TGA) exhibited anticoagulant changes. In contrast, ex-vivo PT or high tissue factor-triggered TGA was indistinguishable from control. Rats receiving single doses (0, 0.01, 0.03, 0.1, 0.3, 1 mg/kg) of FXII siRNA exhibited dose-dependent knockdown in liver FXII mRNA and plasma FXII protein (95 and 99%, respectively, at 1 mg/kg) at day 7 post dosing. FXII knockdown was associated with dose-dependent thromboprotection (maximal efficacy achieved with 1 mg/kg in both models) and negligible change in cuticle bleeding times. Ex-vivo TGA triggered with low-level (0.5 μmol/l) ellagic acid tracked best with the knockdown levels and efficacy. Our findings confirm and extend literature reports of an attractive benefit-to-risk profile of targeting FXII for antithrombotic therapies. Titrating of FXII is instructive for its pharmacological inhibition. The knockout rat is valuable for evaluating both mechanism-based safety concerns and off-target effects of FXII(a) inhibitors. Detailed TGA analyses will inform on optimal trigger conditions in studying pharmacodynamic effects of FXII(a) inhibition.

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Section: Discussionmentioning

confidence: 97%

Factor XII full and partial null in rat confers robust antithrombotic efficacy with no bleeding

Cai¹,

Wu²,

Shin

et al. 2015

Blood Coagulation &Amp; Fibrinolysis

Self Cite

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“…Such insights could lead to a better understanding of the cause of resistant hypertension and provide the basis of targeting AGT. It should be noted that previous reports of blood pressuring lowering with AGT inhibition using RNA-based approaches have been described 24,25 ; however, these studies have an important limitation because of their use of SHRs, a model that already displays robust antihypertensive responses to standard RAAS blockade. In addition, the early ASO studies reported only 40% to 50% maximal reductions of plasma AGT, 26 which would not have been predicted to elicit maximal BP reductions.…”

Section: Discussionmentioning

confidence: 99%

Blood Pressure Lowering and Safety Improvements With Liver Angiotensinogen Inhibition in Models of Hypertension and Kidney Injury

et al. 2017

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566T he discovery and development of renin-angiotensin-aldosterone system (RAAS) inhibitors have established a role of angiotensin II (Ang II) in disease, leading to therapies that are the foundation of treatment for cardiovascular and renal diseases.1 Yet, as effective as RAAS inhibitors have been in the clinic, there is a need to improve the efficacy, safety, and tolerability of this drug class.Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers (ARBs) elicit compensatory pathways resulting in angiotensin reactivation and aldosterone breakthrough such that plasma Ang II and aldosterone return to pretreatment levels or higher. 2,3 This phenomenon may contribute to the suboptimal efficacy of RAAS blockade in patients with resistant hypertension and heart failure. 4,5 Noncanonical pathways of Ang II generation and intracellular RAAS signaling are considered important mechanisms that limit the therapeutic potential of this drug class. 6 AGT (angiotensinogen) is the source of all downstream angiotensin metabolites. The liver is the principal source of circulating AGT, 7-9 although extrahepatic sites of expression, such as in the kidney, have been implicated in the regulation of blood pressure (BP), sodium, and water homeostasis. 10 More aggressive RAAS inhibition, as attempted by combining different classes of RAAS inhibitors, has demonstrated poor clinical utility due in part to adverse effects, such as hyperkalemia, hypotension, and acute renal failure.11 A current hypothesis is that such untoward effects are because of excessive renal RAAS inhibition. 12 Thus, a more effective therapeutic strategy would (1) work upstream of the RAAS enzymes and receptors, thereby avoiding compensatory mechanisms and intracrine signaling that limit therapeutic efficacy, and (2) have limited kidney activity, thereby providing the benefits of aggressive RAAS suppression without provoking renal complications.To this end, we developed a liver-selective AGT antisense oligonucleotide (ASO) that produced potent and durable reductions of liver AGT expression after systemic administration. Liver targeting is achieved by covalent linkage of triantennary N-acetylgalactosamine (GalNAc), a high-affinity ligand for the hepatocyte-specific asialoglycoprotein receptor, to an ASO. This GalNAc-conjugate approach results in enhanced ASO delivery to hepatocytes Abstract-Uncontrolled hypertension is an important contributor to cardiovascular disease. Despite the armamentarium of antihypertensive treatments, there remains a need for novel agents effective in individuals who cannot reach acceptable blood pressure levels. Inhibitors targeting the renin-angiotensin-aldosterone system (RAAS) are widely used but may not optimally inhibit RAAS and demonstrate an acceptable safety profile. Experiments were conducted to characterize a series of AGT (angiotensinogen) antisense oligonucleotides (ASOs) and compare their efficacy and tolerability to traditional RAAS blockade. AGT ASOs which target multiple systemic sites of AGT versus an N...

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“…Chemical inhibitors for ACE and AT1 receptor that target Agt downstream actions are effective agents in treating hypertension and cardiac failure 26 . Additionally, chemical suppression of hepatic Agt using small interference RNA is sufficient for achieving a sustained lower blood pressure in animal models 27 . Our study demonstrated that hepatic Foxo1 regulates Agt gene expression and controls blood pressure, providing a novel regulatory mechanism for the RAS.…”

Section: Discussionmentioning

confidence: 99%

Novel Mechanism of Blood Pressure Regulation By Forkhead Box Class O1–Mediated Transcriptional Control of Hepatic Angiotensinogen

Zhang

et al. 2014

Hypertension

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The renin-angiotensin system (RAS) is a major determinant of blood pressure regulation. It consists of a cascade of enzymatic reactions involving three components: angiotensinogen (Agt), renin, and angiotensin-converting enzyme (ACE), which generate angiotensin II (Ang II) as a biologically active product. Agt is largely produced in the liver, acting as a major determinant of the circulating RAS, which exerts acute hemodynamic effects on blood pressure regulation. How the expression of Agt is regulated is not completely understood. Here we hypothesize that Agt is regulated by forkhead transcription factor forkhead box class O1 (Foxo1), an insulin-suppressed transcription factor, and thereby controls blood pressure in mice. We generated liver-specific Foxo1 knockout mice (L-F1KO mice), which exhibited a reduction in plasma Agt and Ang II levels and a significant decrease in blood pressure. Using hepatocyte cultures, we demonstrated that overexpression of Foxo1 increased Agt expression, while hepatocytes lacking Foxo1 demonstrated a reduction of Agt gene expression and partially impaired insulin inhibition on Agt gene expression. Furthermore, mouse Agt prompter analysis demonstrated that the Agt promoter region contains a functional Foxo1 binding site, which is responsible for both Foxo1 stimulation and insulin suppression on the promoter activity. Together, these data demonstrate that Foxo1 regulates hepatic Agt gene expression and controls plasma Agt and Ang II levels, modulating blood pressure control in mice.

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Targeting of hepatic angiotensinogen using chemically modified siRNAs results in significant and sustained blood pressure lowering in a rat model of hypertension

Cited by 39 publications

References 48 publications

Factor XII full and partial null in rat confers robust antithrombotic efficacy with no bleeding

Factor XII full and partial null in rat confers robust antithrombotic efficacy with no bleeding

Blood Pressure Lowering and Safety Improvements With Liver Angiotensinogen Inhibition in Models of Hypertension and Kidney Injury

Novel Mechanism of Blood Pressure Regulation By Forkhead Box Class O1–Mediated Transcriptional Control of Hepatic Angiotensinogen

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