Lipid-nanoparticle-enabled nucleic acid therapeutics for liver disorders

Abstract

Inherited genetic disorders of the liver pose a significant public health burden. Liver transplantation is often limited by the availability of donor livers and the exorbitant costs of immunosuppressive therapy. To overcome these limitations, nucleic acid therapy provides a hopeful alternative that enables gene repair, gene supplementation, and gene silencing with suitable vectors. Though viral vectors are the most efficient and preferred for gene therapy, pre-existing immunity debilitating immune responses limit their use. As a potential alternative, lipid nanoparticle-mediated vectors are being explored to deliver multiple nucleic acid forms, including pDNA, mRNA, siRNA, and proteins. Herein, we discuss the broader applications of lipid nanoparticles, from protein replacement therapy to restoring the disease mechanism through nucleic acid delivery and gene editing, as well as multiple preclinical and clinical studies as a potential alternative to liver transplantation.

Keywords: ASO; Clinical trials; Gene editing; Gene therapy; Lipid nanoparticle; Liver disorders; Nucleic acid delivery; mRNA; pDNA; siRNA.

Graphical abstract

Figure 1

Lipid-mediated nucleic acid therapy is classified into three primary strategies. To facilitate the disease condition, gene expression is regulated by siRNA or ASO. Using nuclease-based and non-nuclease-based editing tools, gene editing corrects a specific mutant gene to return to the normal phenotype. Gene supplementation delivers functional nucleic acids in pDNA or mRNA form. siRNA, silencing RNA; ASO, anti-sense oligonucleotides; ZFN, zinc finger nucleases; CRISPR, clustered regularly interspaced palindromic repeats; TALENS, transcription activator like effector nucleases; HDR, homologous directed repeat; NHEJ, non-homologous end joining; BE, base editor; PE, prime editor.

Figure 2

Criteria to attain efficient transfection. A liposome and any nucleic acid are combined to form a lipoplex. This lipoplex's efficiency in transfecting the cells depends on Lipid-nanoparticle design, nucleic acid complexation, formulation, DNA-vector design, characterization of the target cell, route of administration, lyophilization, and transfection ability.

Figure 3

Outline of lipid-mediated gene delivery. Liposome and nucleic acid combine to form lipoplex by electrostatic interaction. They enter the target cell through endocytosis. After the early endosomal escape, nucleic acids are released into the cytoplasm, transported to the nucleus, undergo transcription, and are allowed by a translation in the cytoplasm to produce functional protein.

Figure 4

Timeline of nucleic acid and liposome development till 2023. Relevant references are represented as 1, 2, 3-4, 5, 6, 7, 8 (NCT02316457), 9 (NCT03375047), 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 (NCT02316457), 24, 25, 26 within the figure.

Figure 5

Representation of LNP-Based delivery of different nucleic acids to the liver to produce therapeutic protein. (a) Delivery of mRNA+LNP complex. Where mRNA is released into the cytoplasm, thereby making therapeutic protein. (b) siRNA encapsulated LNP performs sequence-specific gene-silencing (c) pDNA+LNP enters the nucleus, followed by transcription and translation in the cytoplasm. (d) Antisense Oligonucleotides are released in the cytoplasm, inhibiting specific gene expression by promoting mRNA degradation.

Figure 6

LNP-mediated base editing for liver disorders. LNP-encapsulated Cas9-ABE mRNA and sgRNA reach the liver, inducing point mutation without causing double-strand breaks, thereby reducing impaired protein levels.