Endothelial siRNA delivery in nonhuman primates using ionizable low–molecular weight polymeric nanoparticles

Abstract

Dysfunctional endothelial cells contribute to the pathophysiology of many diseases, including vascular disease, stroke, hypertension, atherosclerosis, organ failure, diabetes, retinopathy, and cancer. Toward the goal of creating a new RNA-based therapy to correct aberrant endothelial cell gene expression in humans, efficient gene silencing in the endothelium of nonhuman primates was achieved by delivering small interfering RNA (siRNA) with 7C1, a low–molecular weight, ionizable polymer that forms nanoparticles. After a single intravenous administration of 1 mg of siRNA per kilogram of animal, 7C1 nanoparticles delivering Tie2 siRNA caused Tie2 mRNA levels to decrease by approximately 80% in the endothelium of the lung. Significant decreases in Tie2 mRNA were also found in the heart, retina, kidney, pancreas, and bone. Blood chemistry and liver function analysis before and after treatment all showed protein and enzyme concentrations within the normal reference ranges. Furthermore, after controlling for siRNA-specific effects, no significant increases in inflammatory cytokine concentrations were found in the serum. Similarly, no gross lesions or significant underlying pathologies were observed after histological examination of nonhuman primate tissues. This study is the first demonstration of endothelial gene silencing in multiple nonhuman primate organs using systemically administered siRNA nanoparticles and highlights the potential of this approach for the treatment of disease in humans.

Delivering the Messenger: Advances in Technologies for Therapeutic mRNA Delivery

“…Low-molecular-weight polyethyleneimine (PEI) modified with fatty chains has been used for siRNA and mRNA delivery to reduce toxicity of high-molecular weight PEI. [49][50][51][52] Poly(glycoamidoamine) polymers modified with fatty chains, such as TarN3C10 that contains a tartrate backbone, were shown to be potent in delivering erythropoietin (EPO) mRNA in mice. 53 Poly(b-amino)esters (PBAEs) are biodegradable polymers that have been investigated for nucleic acid delivery and were originally developed for DNA transfection.…”

Increased PIP3 activity blocks nanoparticle mRNA delivery

“…LNP2 delivers mRNA to splenic endothelial cells in vivo ( 30 ) and consists of the lipid 7C1 ( 31 ) (fig. S1A), which delivered RNA in NHPs ( 32 ) and is licensed for clinical development. We observed PIP3 dose-dependent inhibition of GFP fluorescence after LNP2 transfection (fig.…”

Gene Therapy for Pancreatic Diseases: Current Status

“…Although the insertion of the catheter is essential, this clinically well-stablished physical and organ-specific gene delivery method can be used for both gene therapy studies and the establishment of pancreatic cancer animal models, in which oncogenic genes can be delivered to the pancreas to study various pancreatic tumor types for the development of appropriate therapeutic strategies. Another approach of siRNA delivery is ionizable low-molecular-weight polymeric nanoparticles, which has been demonstrated in nonhuman primates [ 81 ]. That study showing endothelial gene silencing in multiple nonhuman primate organs using systemically administered siRNA nanoparticles highlights the potential of this approach for the treatment of disease in humans.…”