In the present study, the authors firstly designed 25 siRNA sequences targeting human ANGPTL3 mRNA. Notably, these sequences were generated under the consideration of avoiding affecting highly homologous genes such ANGPTL4 and ANGPTL8, which is favorable to erase potential off-target effects. Subsequently, all siRNAs were armed with chemically modified monomers at specific positions of both strands and conjugated with trivalent GalNAc at the 30 end of the sense strand. After in vitro and in vivo evaluation, ANGsiR10 was finally selected as the lead compound. It completely matches with ANGPTL3 mRNA transcripts of human, monkey, and mouse.

The authors then determined the efficacy and dose regimen of ANGsiR10. The high TG mice received a single subcutaneous injection at doses of 1 and 3 mg/kg, respectively. Continuous lipid monitoring data revealed that ANGsiR10 displayed a dose-dependent pattern. The highest reduction of TG was 96.3%, and total CHO (mainly contributed by the non-HDL-c) was 75.3% in the animals that received the 3 mg/kg siRNA dose. Particularly, a high dose of ANGsiR10 induced a 14-week reduction in blood lipids. In addition, three dose regimens were designed and explored, which demonstrated that 3 mg/kg siRNA with one dose every 4 weeks achieved superior treatment outcomes.

To further evaluate the efficacy of ANGsiR10, a study in a hyperlipidemic monkey model with spontaneous metabolic syndrome was performed. Two parameters, TG and non-HDL-c, were significantly decreased, and the reductions were observed during the whole period of the study. Besides, other beneficial effects such as reduced plasma apolipoproteins and body weight were also observed. The ANGPTL3 mRNA expression in the liver, and the protein level in the serum, were also measured. The results showed that ANGsiR10 efficiently suppressed the expression of mRNA and protein in animals, which proved that all treatment outcomes were mediated by the reduction of ANGPTL3. Finally, histopathology and serum biochemistry analysis suggested that ANGsiR10 exhibited a satisfactory safety profile.