Hepatic delivery systems and action modes of oligonucleotides for liver diseases
GalNAc-ASO/siRNA conjugates are delivered to hepatocytes via the ASGPR expressed on hepatocyte surface. LNPs containing siRNA/miRNA are internalized via the LDLR expressed on the hepatocyte surface. AAV delivers shRNA and miRNA for gene knockdown via primary cell-surface glycoprotein receptors and secondary receptors or universal AAV receptor (AAVR). ASO binds to the target mRNA and attracts RNase H for mRNA degradation. siRNA is loaded into the RISC, leading to targeted mRNA cleavage or translation inhibition. miRNA complementary base pairs with the corresponding miRNA to block the cleavage of targeted mRNA via RISC. GalNAc, N-acetylgalactosamine; LNP, lipid nanoparticle; AAV. adeno-associated virus; LDLR, low-density lipoprotein receptor.