Liver-Specific Ionizable Lipid Nanoparticles Mediated Efficient RNA Interference to Clear “Bad Cholesterol&rdquo

Chuangjia Huang,1,2,* Yu Zhang,3,* Jianfen Su,1,2,* Xiaoling Guan,1,2 Sheng Chen,1,2 Xiaowei Xu,1,2 Xiaohua Deng,1,2 Lingmin Zhang,1,2 Jionghua Huang1 1Department of Cardiology, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, People’s Republic of China; 2Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, the NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, People’s Republic of China; 3Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jionghua Huang; Lingmin Zhang, Email mdhjh2014@126.com; zhanglm@gzhmu.edu.cnBackground: High-level low-density lipoprotein cholesterol (LDL-C) plays a vital role in the development of atherosclerotic cardiovascular disease. Low-density lipoprotein receptors (LDLRs) are scavengers that bind to LDL-C in the liver. LDLR proteins are regulated by proprotein convertase subtilisin/kexin type 9 (PCSK9), which mediates the degradation of LDLR and adjusts the level of the plasma LDL-C. The low expression of PCSK9 leads to the up-regulation of liver LDLRs and the reduction of plasma LDL-C. Hepatocytes are attractive targets for small interfering RNA (siRNA) delivery to silence Pcsk9 gene, due to their significant role in LDL-C regulation.Methods: Here, a type of liver-specific ionizable lipid nanoparticles is developed for efficient siRNA delivery. This type of nanoparticles shows high stability, enabling efficient cargo delivery specifically to hepatocytes, and a membrane-active polymer that reversibly masks activity until an acidic environment is reached.Results: Significantly, the siPcsk9 (siRNA targeting to Pcsk9)-loaded nanoparticles (GLP) could silence 90% of the Pcsk9 mRNA in vitro. In vivo study showed that the improved accumulation of GLP in the liver increased LDLR level by 3.35-fold and decreased plasma LDL-C by 35%.Conclusion: GLP has shown a powerful effect on reducing LDL-C, thus providing a potential therapy for atherosclerotic cardiovascular disease. Keywords: ionizable lipid nanoparticles, bad cholesterol, PCSK9, small interfering RNA, liver-specific delivery