Are Viral Vectors Any Good for RNAi Antiviral Therapy?

siRNA-based therapy for gastric adenocarcinoma: what's next step?

Gastric cancer continues to have a high death rate despite advancements in their diagnosis and treatment. Novel treatment techniques are thus desperately needed. This is where double-stranded RNA molecules known as small interfering RNA (siRNA), which may selectively target the mRNA of disease-causing genes, may find use in medicine. For siRNAs to function properly in the human body, they must be shielded from deterioration. Furthermore, in order to maintain organ function, they must only target the tumor and spare normal tissue. siRNAs have been designed using clever delivery mechanisms including polymers and lipids to achieve these objectives. Although siRNA protection is not hard to acquire, it is still challenging to target cancer cells with them. Here, we first discuss the basic characteristics of gastric cancer before describing the properties of siRNA and typical delivery methods created specifically for gastric tumors. Lastly, we provide a succinct overview of research using siRNAs to treat gastric tumors.

MicroRNA-194-3p impacts autophagy and represses rotavirus replication via targeting silent information regulator 1

BACKGROUND

Rotavirus (RV) is the main cause of serious diarrhea in infants and young children worldwide. Numerous studies have demonstrated that RV use host cell mechanisms to motivate their own stabilization and multiplication by degrading, enhancing, or hijacking microRNAs (miRNAs). Therefore, exploring the molecular mechanisms by which miRNAs motivate or restrain RV replication by controlling different biological processes, including autophagy, will help to better understand the pathogenesis of RV development. This study mainly explored the effect of miR-194-3p on autophagy after RV infection and its underlying mechanism of the regulation of RV replication.

METHODS

Caco-2 cells were infected with RV and used to measure the expression levels of miR-194-3p and silent information regulator 1 (SIRT1). After transfection with plasmids and RV infection, viral structural proteins, RV titer, cell viability, and autophagy-linked proteins were tested. The degree of acetylation of p53 was further investigated. A RV-infected neonatal mouse model was constructed in vivo and was evaluated for diarrhea symptoms and lipid droplet formation.

RESULTS

The results showed that miR-194-3p was reduced but SIRT1 was elevated after RV infection. Elevation of miR-194-3p or repression of SIRT1 inhibited RV replication through the regulation of autophagy. The overexpression of SIRT1 reversed the effects of miR-194-3p on RV replication. The upregulation of miR-194-3p or the downregulation of SIRT1 repressed RV replication in vivo. MiR-194-3p targeted SIRT1 to decrease p53 acetylation.

CONCLUSION

These results were used to determine the mechanism of miR-194-3p in RV replication, and identified a novel therapeutic small RNA molecule that can be used against RV.

Multifunctional magnetic nanocarriers for delivery of siRNA and shRNA plasmid to mammalian cells: Characterization, adsorption and release behaviors

Nucleic acids are promising candidates for treating various diseases. Nucleic acid is negatively charged and hydrophilic; therefore, it is not efficiently taken up by cells. Successful gene therapy requires the development of carriers for efficient delivery of gene-expressing DNA plasmid and small interfering RNA (siRNA) duplex. In this study, we developed MNP-CA-PEI, a citric acid (CA)-modified magnetic nanoparticle (MNP) cross-linked with polyethyleneimine (PEI), using carbonyldiimidazole as the crosslinker. The physical properties of MNP-CA-PEI (particle size, morphologies, surface coating, surface potentials, magnetic hystereses, superparamagnetic behaviors, and infrared spectra) were systematically characterized by transmission electron microscopy imaging, dynamic light scattering, thermogravimetric analysis, superconducting quantum interference device, and Fourier transform infrared spectroscopy. The adsorption isotherm and kinetics were determined by the Langmuir model, the Freundlich model, a pseudo-first-order equation, and a pseudo-second-order equation. MNP-CA-PEI could form polyelectrolyte complexes with negatively charged nucleic acids, enabling the efficient delivery of nucleic acids into cells. Using MNP-CA-PEI nanoparticles, we magnetically triggered the intracellular delivery of green fluorescence protein (GFP)-expressing DNA plasmid, plasmid-expressing short hairpin RNA (shRNA) against GFP, or siRNA targeting GFP into different cell lines. Nucleic acid/MNP-CA-PEI displayed the enhanced cellular uptake of GFP-expressing DNA plasmid, and it improved the silencing efficiency of shRNA and siRNA, determined by fluorescence imaging. Gene knockdowns mediated by shRNA and siRNA were also confirmed by a quantitative real-time polymerase chain reaction. MNP-CA-PEI delivered nucleic acids into cytosol through caveolae-mediated endocytosis. This study introduces a new MNP functionalization that can be used for the magnetically driven intracellular delivery of nucleic acids.

Macrophage membrane- and cRGD-functionalized thermosensitive liposomes combined with CPP to realize precise siRNA delivery into tumor cells

Despite the success of small interfering RNAs (siRNAs) in clinical settings, their fast clearance and poor delivery efficiency to target cells still hinder their therapeutic effect. Herein, a new treatment system was constructed by combining thermosensitive liposomes with the macrophage membrane, tumor-targeting cyclic Arg-Gly-Asp peptide, a cell-penetrating peptide, and thermotherapy. The constructed system was found to be thermosensitive and stable; the proteins were inherited from the macrophage membrane. This new system combined with thermotherapy displayed the least uptake by macrophages, the greatest uptake by HepG2 cells, the most obvious HepG2 cell apoptosis, and the strongest inhibition of Bcl-2 mRNA and Bcl-2 protein in HepG2 cells. Moreover, 24 h after system administration in tumor-bearing mice, the most prominent distribution of siRNA was observed in tumors, while almost no siRNA was found in other organs. The strongest inhibition of Bcl-2 mRNA, Bcl-2 protein, and tumors was found in mice that had received the proposed system. In summary, when using the constructed system both in vitro and in mice, less uptake by the reticuloendothelial system, greater accumulation in tumor cells, and improved therapeutic efficacy were observed. Therefore, this new system can deliver siRNA selectively and efficiently, and it is a promising therapeutic candidate for precise tumor-targeted therapy.

From bench side to clinic: Potential and challenges of RNA vaccines and therapeutics in infectious diseases

The functional and structural versatility of Ribonucleic acids (RNAs) makes them ideal candidates for overcoming the limitations imposed by small molecule-based drugs. Hence, RNA-based biopharmaceuticals such as messenger RNA (mRNA) vaccines, antisense oligonucleotides (ASOs), small interfering RNAs (siRNAs), microRNA mimics, anti-miRNA oligonucleotides (AMOs), aptamers, riboswitches, and CRISPR-Cas9 are emerging as vital tools for the treatment and prophylaxis of many infectious diseases. Some of the major challenges to overcome in the area of RNA-based therapeutics have been the instability of single-stranded RNAs, delivery to the diseased cell, and immunogenicity. However, recent advancements in the delivery systems of in vitro transcribed mRNA and chemical modifications for protection against nucleases and reducing the toxicity of RNA have facilitated the entry of several exogenous RNAs into clinical trials. In this review, we provide an overview of RNA-based vaccines and therapeutics, their production, delivery, current advancements, and future translational potential in treating infectious diseases.

Recent Advances and Challenges in Gene Delivery Mediated by Polyester-Based Nanoparticles

Gene therapy is a promising approach for the treatment of several diseases, such as chronic or viral infections, inherited disorders, and cancer. The cellular internalization of exogenous nucleic acids (NA) requires efficient delivery vehicles to overcome their inherent pharmacokinetic drawbacks, e.g. electrostatic repulsions, enzymatic degradation, limited cellular uptake, fast clearance, etc. Nanotechnological advancements have enabled the use of polymer-based nanostructured biomaterials as safe and effective gene delivery systems, in addition to viral vector delivery methods. Among the plethora of polymeric nanoparticles (NPs), this review will provide a comprehensive and in-depth summary of the polyester-based nanovehicles, including poly(lactic-co-glycolic acid) (PLGA) and polylactic acid (PLA) NPs, used to deliver a variety of foreign NA, e.g. short interfering RNA (siRNA), messenger RNA (mRNA), and plasmid DNA (pDNA). The article will review the versatility of polyester-based nanocarriers including their recent application in the delivery of the clustered, regularly-interspaced, short palindromic repeats/Cas (CRISPR/Cas) genome editing system for treating gene-related diseases. The remaining challenges and future trend of the targeted delivery of this revolutionary genome-editing system will be discussed. Special attention will be given to the pivotal role of nanotechnology in tackling emerging infections such as coronavirus disease 2019 (COVID-19): ground-breaking mRNA vaccines delivered by NPs are currently used worldwide to fight the pandemic, pushing the boundaries of gene therapy.

Suppression of Human Coronavirus 229E Infection in Lung Fibroblast Cells via RNA Interference

Despite extensive efforts to repurpose approved drugs, discover new small molecules, and develop vaccines, COVID-19 pandemic is still claiming victims around the world. The current arsenal of antiviral compounds did not perform well in the past viral infections (e.g., SARS), which casts a shadow of doubt for use against the new SARS-CoV-2. Vaccines should offer the ultimate protection; however, there is limited information about the longevity of the generated immunity and the protection against possible mutations. This study uses Human Coronavirus 229E as a model coronavirus to test the hypothesis that effective delivery of virus-specific siRNAs to infected cells will result in lower viral load and reduced cell death. Two different categories of nucleic acid delivery systems, Peptide/Lipid-Associated Nucleic Acids (PLANAs) and lipophilic polymers, were investigated for their toxicity in human lung fibroblast cells and their ability to deliver specific siRNAs targeting Spike and Envelope proteins in order to prevent cell death in infected cells. Selected siRNAs were effectively delivered to human lung fibroblast cells with negligible toxicity. Cell death due to viral infection was significantly reduced with individual and combinatorial silencing of selected viral proteins. The combinatorial silencing of Spike and Envelope proteins restored the cell viability completely and eliminated plaques in the investigated system. Our cell culture data indicate promising results for the RNAi based approach as an alternative antiviral treatment.