Preclinical and Clinical Development of Noncoding RNA Therapeutics for Cardiovascular Disease

Abstract

RNA modulation has become a promising therapeutic approach for the treatment of several types of disease. The emerging field of noncoding RNA-based therapies has now come to the attention of cardiovascular research, in which it could provide valuable advancements in comparison to current pharmacotherapy such as small molecule drugs or antibodies. In this review, we focus on noncoding RNA-based studies conducted mainly in large-animal models, including pigs, rabbits, dogs, and nonhuman primates. The obstacles and promises of targeting long noncoding RNAs and circRNAs as therapeutic modalities in humans are specifically discussed. We also describe novel ex vivo methods based on human cells and tissues, such as engineered heart tissues and living myocardial slices that could help bridging the gap between in vivo models and clinical applications in the future. Finally, we summarize antisense oligonucleotide drugs that have already been approved by the Food and Drug Administration for targeting mRNAs and discuss the progress of noncoding RNA-based drugs in clinical trials. Additional factors, such as drug chemistry, drug formulations, different routes of administration, and the advantages of RNA-based drugs, are also included in the present review. Recently, first therapeutic miRNA-based inhibitory strategies have been tested in heart failure patients as well as healthy volunteers to study effects on wound healing (NCT04045405; NCT03603431). In summary, a combination of novel therapeutic RNA targets, large-animal models, ex vivo studies with human cells/tissues, and new delivery techniques will likely lead to significant progress in the development of noncoding RNA-based next-generation therapeutics for cardiovascular disease.

Keywords: animal models; cardiovascular diseases; nucleic acids; nucleosides; nucleotides; therapeutics.

Figures

Figure 1.

Scheme of oligonucleotide-based RNA delivery.A, AntimiRs (miRNA inhibitors) can be modified with different chemical modifications, including locked nucleic acids (LNAs) and sugar backbone modifications (2’-O-Me, 2’-F/MOE, and 2’-O-MOE), while miRNA can also be enhanced via miRNA mimics. To inhibit mRNAs or long noncoding RNAs (lncRNAs), short hairpin RNAs (shRNAs), or LNA/GapmeR are commonly used. B, Adenovirus, adenoassociated virus (AAV), and lentivirus particles can be used as a vector to silence or overexpress target genes. In addition to viral-based delivery, liposomes or nanoparticles are another way through which to deliver antimiRs or miRNA mimics. C, Various delivery approaches can be applied in different species. For example, atrium injection is performed in rabbits and dogs with atrial fibrillation. For pigs, intravenous injection, catheter-based injection, and intracoronary injection are commonly used. Subcutaneous injection can be also used. Clinically, subcutaneous injection, intravenous injection, and intradermal injection are more attractive and easier delivery routes in humans.

Figure 2.

Workflow of 2 3-dimensional ex vivo models, engineered heart tissues (EHTs), and living myocardial slices.A, Somatic cells are isolated from human blood cells or skin cells, reprogrammed into human induced pluripotent stem cells (hiPSCs), and differentiated into hiPSC-derived cardiomyocytes (hiPSC-CMs). The hiPSC-CMs are seeded onto the scaffolds to generate beating EHTs. Compared with a 2-dimensional cell culture system, EHTs exhibit a better structure and matured phenotypes that are similar to adult CMs. Through modifying the stiffness of the scaffold, different disease models, such as hypertrophic cardiomyopathy, can be established. EHTs can further be tested for drugs or as gene modulation tools. Not only stemming from healthy humans, EHTs can also be made from patients suffering from heart disease for disease modeling. B, To prepare living myocardial slices, small or large mammalian hearts, including human hearts, are explanted. The left ventricles or other parts of the heart are then isolated and dissected into small tissue blocks. Hundred to four hundred micrometers myocardial slices are sliced and used for further functional studies, for example, by treating with different drugs or adjusting the voltage that stimulates the contraction of the myocardial slices. Similar to EHTs, the living myocardial slices could also be prepared from diseased animal models. Doxo indicates doxorubicin; ISO, isoproterenol; and PE, phenylephrine.

Figure 3.

Processes of noncoding RNA (ncRNA)-based drug development. Novel ncRNA candidates are selected from a RNA-seq profile or other ncRNA approaches, and then validated in cardiovascular cells (in vitro). After basic characterization, the ncRNA candidates are further investigated in animal models (in vivo). Several pathophysiological animal models of cardiovascular complication are available in different species, ranging from small to large animals, via the application of surgical techniques, genetic engineering, or diet changes. Some effective yet nontoxic ncRNA candidates are selected for further clinical development. However, successful transitions from preclinical to clinical studies are generally small in number. Often, in vitro models are easy to apply but have limited clinical relevance; while in vivo models have higher clinical relevance, they are challenging to conduct and expensive. To increase the translational efficiency of ncRNA-based therapeutic human induced pluripotent stem cells and/or other human cardiovascular cell types and living myocardial slices, could be powerful tools to bridge the gap between in vivo and clinical development. IRI indicates ischemia-reperfusion injury; and TAC, transverse aortic constriction.