Modified mRNA as a Therapeutic Tool for the Heart

Abstract

Despite various clinical modalities available for patients, heart disease remains among the leading causes of mortality and morbidity worldwide. Genetic medicine, particularly mRNA, has broad potential as a therapeutic. More specifically, mRNAbased protein delivery has been used in the fields of cancer and vaccination, but recent changes to the structural composition of mRNA have led the scientific community to swiftly embrace it as a new drug to deliver missing genes to injured myocardium and many other organs. Modified mRNA (modRNA)-based gene delivery features transient but potent protein translation and low immunogenicity, with minimal risk of insertional mutagenesis. In this review, we compared and listed the advantages of modRNA over traditional vectors for cardiac therapy, with particular focus on using modRNA therapy in cardiac repair. We present a comprehensive overview of modRNA's role in cardiomyocyte (CM) proliferation, cardiac vascularization, and prevention of cardiac apoptosis. We also emphasize recent advances in modRNA delivery strategies and discuss the challenges for its clinical translation.

mRNA-Enhanced Cell Therapy and Cardiovascular Regeneration

“…With improvements in mRNA constructs to improve their stability, enhance translation and promote delivery to the target tissue, the field of RNA Therapeutics is growing exponentially and advancing to clinical applications [ 93 , 94 ]. The recent success of mRNA vaccines against SARS-CoV-2 [ 3 , 4 ] has attracted great interest which will further accelerate the growth of this exciting frontier in medicine.…”

Transient induction of cell cycle promoter Fam64a improves cardiac function through regulating Klf15-dependent cardiomyocyte differentiation in mice

“…On the basis of the findings that long-term induction of Fam64a in TG mice hearts exacerbates cardiac function, we next tested whether transient induction of Fam64a upon injury is beneficial. We used the protocol with direct intramyocardial injection of mRNA encoding Fam64a-FLAG or control EGFP immediately after cryoinjury in WT adult hearts (modified from Kaur and Zangi, 2020;Strungs et al, 2013). This protocol ensured the expression of the Fam64a-FLAG fusion protein in the CM nuclei (Figure 7A).…”

“…This PCR product was purified using FastGene Gel/PCR Extraction Kit (Nippon Genetics, Japan), and was used as the template for modified mRNA synthesis. In vitro transcription was performed using HiScribe T7 High Yield RNA Synthesis Kit (New England Biolabs, USA) with a customized ribonucleoside blend of GTP (1.5 mM), ATP (7.5 mM), CTP (7.5mM), N1-Methylpseudo-UTP (7.5 mM, N-1081, TriLink Biotechnologies), and CleanCap® Reagent AG (6 mM, N-7113, TriLink Biotechnologies, USA) (Zangi et al, 2017;Kaur and Zangi, 2020). Following the purification of transcribed mRNA using Fast Gene RNA Premium Kit (Nippon Genetics), Poly (A) tailing reaction was performed using E. coli Poly (A) polymerase (New England Biolabs), and mRNA was re-purified with the same kit.…”

Recent Advances in Gene Therapy for Atrial Fibrillation

“…modRNA gene delivery has minimal risk of integration into the host genome. 26 modRNA has been shown to be highly efficient with robust transient expression with no sign of innate immune response. 27 ModRNA is translated within minutes and lasts up to 10 days in vivo.…”