Adenovirus vector-mediated RNA interference for the inhibition of human parvovirus B19 replication

Strategic deactivation of mRNA COVID-19 vaccines: New applications for siRNA therapy and RIBOTACs

The rapid development and authorization of messenger ribonucleic acid (mRNA) vaccines by Pfizer-BioNTech (BNT162b2) and Moderna (mRNA-1273) in 2020 marked a significant milestone in human mRNA product application, overcoming previous obstacles such as mRNA instability and immunogenicity. This paper reviews the strategic modifications incorporated into these vaccines to enhance mRNA stability and translation efficiency, such as the inclusion of nucleoside modifications and optimized mRNA design elements including the 5' cap and poly(A) tail. We highlight emerging concerns regarding the wide systemic biodistribution of these mRNA vaccines leading to prolonged inflammatory responses and other safety concerns. The regulatory framework guiding the biodistribution studies is pivotal in assessing the safety profiles of new mRNA formulations in use today. The stability of mRNA vaccines, their pervasive distribution, and the longevity of the encapsulated mRNA along with unlimited production of the damaging and potentially lethal spike (S) protein call for strategies to mitigate potential adverse effects. Here, we explore the potential of small interfering RNA (siRNA) and ribonuclease targeting chimeras (RIBOTACs) as promising solutions to target, inactivate, and degrade residual and persistent vaccine mRNA, thereby potentially preventing uncontrolled S protein production and reducing toxicity. The targeted nature of siRNA and RIBOTACs allows for precise intervention, offering a path to prevent and mitigate adverse events of mRNA-based therapies. This review calls for further research into siRNA and RIBOTAC applications as antidotes and detoxication products for mRNA vaccine technology.

Antiviral alternatives against important members of the subfamily Parvovirinae: a review

Parvoviruses are responsible for multiple diseases, and there is a critical need for effective antiviral therapies. Specific antiviral treatments for parvovirus infections are currently lacking, and the available options are mostly supportive and symptomatic. In recent years, significant research efforts have been directed toward understanding the molecular mechanisms of parvovirus replication and identifying potential targets for antiviral interventions. This review highlights the structure, pathogenesis, and treatment options for major viruses of the subfamily Parvovirinae, such as parvovirus B19 (B19V), canine parvovirus type 2 (CPV-2), and porcine parvovirus (PPV) and also describes different approaches in the development of antiviral alternatives against parvovirus, including drug repurposing, serendipity, and computational tools (molecular docking and artificial intelligence) in drug discovery. These advances greatly increase the likelihood of discoveries that will lead to potent antiviral strategies against different parvovirus infections.

A Comprehensive Review of Small Interfering RNAs (siRNAs): Mechanism, Therapeutic Targets, and Delivery Strategies for Cancer Therapy

Small interfering RNA (siRNA) delivery by nanocarriers has been identified as a promising strategy in the study and treatment of cancer. Short nucleotide sequences are synthesized exogenously to create siRNA, which triggers RNA interference (RNAi) in cells and silences target gene expression in a sequence-specific way. As a nucleic acid-based medicine that has gained popularity recently, siRNA exhibits novel potential for the treatment of cancer. However, there are still many obstacles to overcome before clinical siRNA delivery devices can be developed. In this review, we discuss prospective targets for siRNA drug design, explain siRNA drug properties and benefits, and give an overview of the current clinical siRNA therapeutics for the treatment of cancer. Additionally, we introduce the siRNA chemical modifications and delivery systems that are clinically sophisticated and classify bioresponsive materials for siRNA release in a methodical manner. This review will serve as a reference for researchers in developing more precise and efficient targeted delivery systems, promoting ongoing advances in clinical applications.

Inhibition of encephalomyocarditis virus replication by shRNA targeting 1C and 2A genes in vitro and in vivo

Encephalomyocarditis virus (EMCV) infects many mammalian species, causing myocarditis, encephalitis and reproductive disorders. The small interference RNA (siRNA) targeting to the virus has not been understood completely. Here, two out of six interference sequences were screened to inhibit significantly EMCV replication by using recombinant plasmids expressing small hairpin RNA (shRNA) targeting to the viral 1C or 2A genes in BHK-21 cells. And two recombinant adenoviruses expressing the shRNAs were constructed and named as rAd-1C-1 and rAd-2A-3. They inhibit EMCV replication in BHK-21 cells in protein levels, as well as the virus yields by approximately 1000 times. Furthermore, they provide high protective efficacy against the challenge with virulent EMCV NJ08 strain in mice. And the EMCV loads in the live mice in rAd-1C-1 and rAd-2A-3 groups decrease by more than 90 % compared with those in the dead mice in the challenge control groups at the same times. It indicates that the adenoviruses medicated shRNA targeting to 1C and 2A genes might provide a potential strategy for combating EMCV infection.

Editorial focus: understanding off-target effects as the key to successful RNAi therapy

With the first RNA interference (RNAi) drug (ONPATTRO (patisiran)) on the market, we witness the RNAi therapy field reaching a critical turning point, when further improvements in drug candidate design and delivery pipelines should enable fast delivery of novel life changing treatments to patients. Nevertheless, ignoring parallel development of RNAi dedicated in vitro pharmacological profiling aiming to identify undesirable off-target activity may slow down or halt progress in the RNAi field. Since academic research is currently fueling the RNAi development pipeline with new therapeutic options, the objective of this article is to briefly summarize the basics of RNAi therapy, as well as to discuss how to translate basic research into better understanding of related drug candidate safety profiles early in the process.

siRNA Versus miRNA as Therapeutics for Gene Silencing

Discovered a little over two decades ago, small interfering RNAs (siRNAs) and microRNAs (miRNAs) are noncoding RNAs with important roles in gene regulation. They have recently been investigated as novel classes of therapeutic agents for the treatment of a wide range of disorders including cancers and infections. Clinical trials of siRNA- and miRNA-based drugs have already been initiated. siRNAs and miRNAs share many similarities, both are short duplex RNA molecules that exert gene silencing effects at the post-transcriptional level by targeting messenger RNA (mRNA), yet their mechanisms of action and clinical applications are distinct. The major difference between siRNAs and miRNAs is that the former are highly specific with only one mRNA target, whereas the latter have multiple targets. The therapeutic approaches of siRNAs and miRNAs are therefore very different. Hence, this review provides a comparison between therapeutic siRNAs and miRNAs in terms of their mechanisms of action, physicochemical properties, delivery, and clinical applications. Moreover, the challenges in developing both classes of RNA as therapeutics are also discussed.