Development of nucleic acid medicines based on chemical technology

A Visual Compendium of Principal Modifications within the Nucleic Acid Sugar Phosphate Backbone

Nucleic acid chemistry is a huge research area that has received new impetus due to the recent explosive success of oligonucleotide therapy. In order for an oligonucleotide to become clinically effective, its monomeric parts are subjected to modifications. Although a large number of redesigned natural nucleic acids have been proposed in recent years, the vast majority of them are combinations of simple modifications proposed over the past 50 years. This review is devoted to the main modifications of the sugar phosphate backbone of natural nucleic acids known to date. Here, we propose a systematization of existing knowledge about modifications of nucleic acid monomers and an acceptable classification from the point of view of chemical logic. The visual representation is intended to inspire researchers to create a new type of modification or an original combination of known modifications that will produce unique oligonucleotides with valuable characteristics.

Multivalent dendritic DNA aptamer molecules for the enhancement of therapeutic effects

Dendritic DNA molecules, referred to as DNA dendrons, consist of multiple covalently linked strands and are expected to improve the cellular uptake and potency of therapeutic oligonucleotides because of their multivalency. In this study, we developed an efficient synthetic method for producing DNA dendrons using strain-promoted azide-alkyne cycloaddition. Integration of the antitumor aptamer AS1411 into DNA dendrons enhanced cellular uptake and antiproliferative activity in cancer cells. These findings demonstrate that the incorporation of multivalent aptamers into DNA dendrons can effectively boost their therapeutic effects.

Frameworks for transformational breakthroughs in RNA-based medicines

RNA has sparked a revolution in modern medicine, with the potential to transform the way we treat diseases. Recent regulatory approvals, hundreds of new clinical trials, the emergence of CRISPR gene editing, and the effectiveness of mRNA vaccines in dramatic response to the COVID-19 pandemic have converged to create tremendous momentum and expectation. However, challenges with this relatively new class of drugs persist and require specialized knowledge and expertise to overcome. This Review explores shared strategies for developing RNA drug platforms, including layering technologies, addressing common biases and identifying gaps in understanding. It discusses the potential of RNA-based therapeutics to transform medicine, as well as the challenges associated with improving applicability, efficacy and safety profiles. Insights gained from RNA modalities such as antisense oligonucleotides (ASOs) and small interfering RNAs are used to identify important next steps for mRNA and gene editing technologies.

An engineered poly(A) tail attenuates gut ischemia/reperfusion-induced acute lung injury

BACKGROUND

Gut ischemia/reperfusion causes the release of damage-associated molecular patterns, leading to acute lung injury and high mortality. Cold-inducible ribonucleic acid-binding protein is a ribonucleic acid chaperon that binds the polyadenylation tail of messenger ribonucleic acid intracellularly. Upon cell stress, cold-inducible ribonucleic acid-binding protein is released, and extracellular cold-inducible ribonucleic acid-binding protein acts as a damage-associated molecular pattern, worsening inflammation. To inhibit extracellular cold-inducible ribonucleic acid-binding protein, we have recently developed an engineered polyadenylation tail named A12. Here, we sought to investigate the therapeutic potential of A12 in gut ischemia/reperfusion-induced acute lung injury.

METHODS

Male C57BL6/J mice underwent superior mesenteric artery occlusion and were treated with intraperitoneal A12 (0.5 nmol/g body weight) or vehicle at the time of reperfusion. Blood and lungs were collected 4 hours after gut ischemia/reperfusion. Systemic levels of extracellular cold-inducible ribonucleic acid-binding protein, interleukin-6, aspartate transaminase, alanine transaminase, and lactate dehydrogenase were determined. The pulmonary gene expression of cytokines (interleukin-6, interleukin-1β) and chemokines (macrophage-inflammatory protein-2, keratinocyte-derived chemokine) was also assessed. In addition, lung myeloperoxidase, injury score, and cell death were determined. Mice were monitored for 48 hours after gut ischemia/reperfusion for survival assessment.

RESULTS

Gut ischemia/reperfusion significantly increased the serum extracellular cold-inducible ribonucleic acid-binding protein levels. A12 treatment markedly reduced the elevated serum interleukin-6, alanine transaminase, aspartate transaminase, and lactate dehydrogenase by 53%, 23%, 23%, and 24%, respectively, in gut ischemia/reperfusion mice. A12 also significantly decreased cytokine and chemokine messenger ribonucleic acids and myeloperoxidase activity in the lungs of gut ischemia/reperfusion mice. Histological analysis revealed that A12 attenuated tissue injury and cell death in the lungs of gut ischemia/reperfusion mice. Finally, administration of A12 markedly improved the survival of gut ischemia/reperfusion mice.

CONCLUSION

A12, a novel extracellular cold-inducible ribonucleic acid-binding protein inhibitor, diminishes inflammation and mitigates acute lung injury when employed as a treatment during gut ischemia/reperfusion. Hence, the targeted approach toward extracellular cold-inducible ribonucleic acid-binding protein emerges as a promising therapeutic strategy for alleviating gut ischemia/reperfusion-induced acute lung injury.

Liquid Droplet-Mediated Formulation of Lipid Nanoparticles Encapsulating Immunoglobulin G for Cytosolic Delivery

Antibodies are promising biopharmaceuticals that offer new therapeutic options for diseases. Since antibodies are membrane impermeable, approaches that allow immunoglobulin Gs (IgGs) to access intracellular therapeutic targets would open new horizons in antibody therapies. Lipid nanoparticles (LNPs) are among the classes of vectors that deliver biopharmaceuticals into cells. Using liquid droplets formed by IgG and polyglutamate, we report here a unique approach to forming LNPs containing IgG via liquid droplets formed in the presence of polyglutamic acid (polyE). The addition of polyE promoted the formation of smaller LNPs with cationic lipids than in its absence, and the formed LNPs were much more efficient in cytosolic IgG delivery and targeting of cellular proteins. This approach also allows for the encapsulation of intact IgG without the need for chemical or sequence modification. The intracellularly delivered IgG retained its target binding ability, as demonstrated by labeling of nuclear pore complex and HRas-GFP and inhibition of antiapoptotic cell death by phosphorylated Akt protein in live cells.

Organometallic modification confers oligonucleotides new functionalities

To improve their properties or to introduce entirely new functionalities, the intriguing scaffolds of nucleic acids have been decorated with various modifications, most recently also organometallic ones. While challenging to introduce, organometallic modifications offer the potential of expanding the field of application of metal-dependent functionalities to metal-deficient conditions, notably those of biological media. So far, organometallic moieties have been utilized as probes, labels and catalysts. This Feature Article summarizes recent efforts and predicts likely future developments in each of these lines of research.