Strategies for Improving siRNA-Induced Gene Silencing Efficiency

Advances and challenges in gene therapy strategies for pediatric cancer: a comprehensive update

Pediatric cancers represent a tragic but also promising area for gene therapy. Although conventional treatments have improved survival rates, there is still a need for targeted and less toxic interventions. This article critically analyzes recent advances in gene therapy for pediatric malignancies and discusses the challenges that remain. We explore the innovative vectors and delivery systems that have emerged, such as adeno-associated viruses and non-viral platforms, which show promise in addressing the unique pathophysiology of pediatric tumors. Specifically, we examine the field of chimeric antigen receptor (CAR) T-cell therapies and their adaptation for solid tumors, which historically have been more challenging to treat than hematologic malignancies. We also discuss the genetic and epigenetic complexities inherent to pediatric cancers, such as tumor heterogeneity and the dynamic tumor microenvironment, which pose significant hurdles for gene therapy. Ethical considerations specific to pediatric populations, including consent and long-term follow-up, are also analyzed. Additionally, we scrutinize the translation of research from preclinical models that often fail to mimic pediatric cancer biology to the regulatory landscapes that can either support or hinder innovation. In summary, this article provides an up-to-date overview of gene therapy in pediatric oncology, highlighting both the rapid scientific progress and the substantial obstacles that need to be addressed. Through this lens, we propose a roadmap for future research that prioritizes the safety, efficacy, and complex ethical considerations involved in treating pediatric patients. Our ultimate goal is to move from incremental advancements to transformative therapies.

Designing Cell Delivery Peptides and SARS-CoV-2-Targeting Small Interfering RNAs: A Comprehensive Bioinformatics Study with Generative Adversarial Network-Based Peptide Design and In Vitro Assays

Nucleic acid technologies with designed intracellular delivery systems are some of the most promising therapies of the future. Small interfering (si)RNAs inhibit gene expression and protein synthesis and may complement current vaccines with faster design and production. Although successful delivery remains an issue, delivery peptides may help to fill this gap. Here, we address this issue by applying bioinformatic approaches to design new putative cell delivery peptides and siRNAs for COVID-19 variants and other related viral diseases. Of the 29,880 RNA sequences analyzed, 62 were identified in silico as able to target the virus mRNA sequence, and from the 9,984 peptide sequences analyzed, 10 were selected as delivery peptides. From the latter, we further performed in vitro studies of the two best-ranked peptides and compared them with the broadly used TAT delivery peptide. One of them, seq5, displayed better internalization results with about double intensity signal compared to TAT after a 1 h incubation time in GFP-HeLa cells. This peptide has, thus, the features of a delivery peptide and could be used for cargo intracellular delivery.

Critical points for the design and application of RNA silencing constructs for plant virus resistance

Control of plant virus diseases is a big challenge in agriculture as is resistance in plant lines to infection by viruses. Recent progress using advanced technologies has provided fast and durable alternatives. One of the most promising techniques against plant viruses that is cost-effective and environmentally safe is RNA silencing or RNA interference (RNAi), a technology that could be used alone or along with other control methods. To achieve the goals of fast and durable resistance, the expressed and target RNAs have been examined in many studies, with regard to the variability in silencing efficiency, which is regulated by various factors such as target sequences, target accessibility, RNA secondary structures, sequence variation in matching positions, and other intrinsic characteristics of various small RNAs. Developing a comprehensive and applicable toolbox for the prediction and construction of RNAi helps researchers to achieve the acceptable performance level of silencing elements. Although the attainment of complete prediction of RNAi robustness is not possible, as it also depends on the cellular genetic background and the nature of the target sequences, some important critical points have been discerned. Thus, the efficiency and robustness of RNA silencing against viruses can be improved by considering the various parameters of the target sequence and the construct design. In this review, we provide a comprehensive treatise regarding past, present and future prospective developments toward designing and applying RNAi constructs for resistance to plant viruses.

The potential of RNA-based therapy for kidney diseases

Inherited kidney diseases (IKDs) are a large group of disorders affecting different nephron segments, many of which progress towards kidney failure due to the absence of curative therapies. With the current advances in genetic testing, the understanding of the molecular basis and pathophysiology of these disorders is increasing and reveals new potential therapeutic targets. RNA has revolutionized the world of molecular therapy and RNA-based therapeutics have started to emerge in the kidney field. To apply these therapies for inherited kidney disorders, several aspects require attention. First, the mRNA must be combined with a delivery vehicle that protects the oligonucleotides from degradation in the blood stream. Several types of delivery vehicles have been investigated, including lipid-based, peptide-based, and polymer-based ones. Currently, lipid nanoparticles are the most frequently used formulation for systemic siRNA and mRNA delivery. Second, while the glomerulus and tubules can be reached by charge- and/or size-selectivity, delivery vehicles can also be equipped with antibodies, antibody fragments, targeting peptides, carbohydrates or small molecules to actively target receptors on the proximal tubule epithelial cells, podocytes, mesangial cells or the glomerular endothelium. Furthermore, local injection strategies can circumvent the sequestration of RNA formulations in the liver and physical triggers can also enhance kidney-specific uptake. In this review, we provide an overview of current and potential future RNA-based therapies and targeting strategies that are in development for kidney diseases, with particular interest in inherited kidney disorders.

TREAT: Therapeutic RNAs exploration inspired by artificial intelligence technology

Recent advances in RNA engineering have enabled the development of RNA-based therapeutics for a broad spectrum of applications. Developing RNA therapeutics start with targeted RNA screening and move to the drug design and optimization. However, existing target screening tools ignore noncoding RNAs and their disease-relevant regulatory relationships. And designing therapeutic RNAs encounters high computational complexity of multi-objective optimization to overcome the immunogenicity, instability and inefficient translational production. To unlock the therapeutic potential of noncoding RNAs and enable one-stop screening and design of therapeutic RNAs, we have built the platform TREAT. It incorporates 43,087,953 regulatory relationships between coding and noncoding genes from 81 biological networks under different physiological conditions. TREAT introduces graph representation learning with Random Walk Diffusions to perform disease-relevant target screening, in addition to the commonly utilized Topological Degree and PageRank algorithms. Design and optimization of large RNAs or interfering RNAs are both available. To reduce the computational complexity of multi-objective optimization for large RNA, we stratified the features into local and global features. The local features are evaluated on the fixed-length or dynamic-length local bins, whereas the latter are inspired by AI language models of protein sequence. Then the global assessment is performed on refined candidates, thus reducing the enormous search space. Overall, TREAT is a one-stop platform for the screening and designing of therapeutic RNAs, with particular attention to noncoding RNAs and cutting-edge AI technology embedded, leading the progress of innovative therapeutics for challenging diseases. TREAT is freely accessible at https://rna.org.cn/treat.

Therapeutic siRNA: State-of-the-Art and Future Perspectives

The highly specific induction of RNA interference-mediated gene knockdown, based on the direct application of small interfering RNAs (siRNAs), opens novel avenues towards innovative therapies. Two decades after the discovery of the RNA interference mechanism, the first siRNA drugs received approval for clinical use by the US Food and Drug Administration and the European Medicines Agency between 2018 and 2022. These are mainly based on an siRNA conjugation with a targeting moiety for liver hepatocytes, N-acetylgalactosamine, and cover the treatment of acute hepatic porphyria, transthyretin-mediated amyloidosis, hypercholesterolemia, and primary hyperoxaluria type 1. Still, the development of siRNA therapeutics faces several challenges and issues, including the definition of optimal siRNAs in terms of target, sequence, and chemical modifications, siRNA delivery to its intended site of action, and the absence of unspecific off-target effects. Further siRNA drugs are in clinical studies, based on different delivery systems and covering a wide range of different pathologies including metabolic diseases, hematology, infectious diseases, oncology, ocular diseases, and others. This article reviews the knowledge on siRNA design and chemical modification, as well as issues related to siRNA delivery that may be addressed using different delivery systems. Details on the mode of action and clinical status of the various siRNA therapeutics are provided, before giving an outlook on issues regarding the future of siRNA drugs and on their potential as one emerging standard modality in pharmacotherapy. Notably, this may also cover otherwise un-druggable diseases, the definition of non-coding RNAs as targets, and novel concepts of personalized and combination treatment regimens.

Mesoporous silica-coated silver nanoparticles as ciprofloxacin/siRNA carriers for accelerated infected wound healing

The colonization of bacterial pathogens is a major concern in wound infection and becoming a public health issue. Herein, a core–shell structured Ag@MSN (silver core embedded with mesoporous silica, AM)-based nanoplatform was elaborately fabricated to co-load ciprofloxacin (CFL) and tumor necrosis factor-α (TNF-α) small interfering RNA (siTNF-α) (AMPC@siTNF-α) for treating the bacterial-infected wound. The growth of bacterial pathogens was mostly inhibited by released silver ions (Ag⁺) and CFL from AMPC@siTNF-α. Meanwhile, the loaded siTNF-α was internalized by macrophage cells, which silenced the expression of TNF-α (a pro-inflammatory cytokine) in macrophage cells and accelerated the wound healing process by reducing inflammation response. In the in vivo wound model, the Escherichia coli (E. coli)-infected wound in mice almost completely disappeared after treatment with AMPC@siTNF-α, and no suppuration symptom was observed during the course of the treatment. Importantly, this nanoplatform had negligible side effects both in vitro and in vivo. Taken together, this study strongly demonstrates the promising potential of AMPC@siTNF-α as a synergistic therapeutic agent for clinical wound infections.

In Silico Design of siRNAs for Silencing CLEC5A Receptor as a Potential Therapeutic Approach Against Dengue and Japanese Encephalitis Virus Infection in Human

Dengue and Japanese encephalitis virus (JEV) are mosquito-borne RNA viruses that can cause severe illness leading to death in the tropics and subtropics. Both of these viruses interact directly with the C-type lectin domain family 5, member A receptor (CLEC5A) on human macrophages which stimulates the release of proinflammatory cytokines. Since blockade of this interaction has been shown to suppress the secretion of cytokines, CLEC5A is considered a potential target for the development of new treatments to reduce virus-induced brain damage. Developing a vaccine against dengue is challenging because this virus can cause disease through 4 different serotypes. Therefore, the vaccine must immunize against all 4 serotypes to be effective, while unvaccinated people still contract JEV and suffer from its complications. Small interfering RNAs (siRNAs) play an important role in regulating gene expression by causing the degradation of target mRNAs. In this study, we attempted to rationally design potential siRNA molecules using various software, targeting the CLEC5A gene. In total, 3 siRNAs were found to be potential candidates for CLEC5A silencing. They showed good target accessibility, optimum guanine-cytosine (GC) content, the least chance of off-target effects, positive energy of folding, and strong interaction with Argonaute2 protein as denoted by a negative docking energy score. In addition, molecular dynamics simulation of the siRNA-Ago2-docked complexes showed the stability of the complexes over 1.5 nanoseconds. These predicted siRNAs might effectively downregulate the expression of the CLEC5A receptor and thus prove vital in the treatment of dengue and JEV infections.

In Vitro Methods to Decipher the Structure of Viral RNA Genomes

RNA viruses encode essential information in their genomes as conserved structural elements that are involved in efficient viral protein synthesis, replication, and encapsidation. These elements can also establish complex networks of RNA-RNA interactions, the so-called RNA interactome, to shape the viral genome and control different events during intracellular infection. In recent years, targeting these conserved structural elements has become a promising strategy for the development of new antiviral tools due to their sequence and structural conservation. In this context, RNA-based specific therapeutic strategies, such as the use of siRNAs have been extensively pursued to target the genome of different viruses. Importantly, siRNA-mediated targeting is not a straightforward approach and its efficiency is highly dependent on the structure of the target region. Therefore, the knowledge of the viral structure is critical for the identification of potentially good target sites. Here, we describe detailed protocols used in our laboratory for the in vitro study of the structure of viral RNA genomes. These protocols include DMS (dimethylsulfate) probing, SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) analysis, and HMX (2'-hydroxyl molecular interference). These methodologies involve the use of high-throughput analysis techniques that provide extensive information about the 3D folding of the RNA under study and the structural tuning derived from the interactome activity. They are therefore a good tool for the development of new RNA-based antiviral compounds.

Clustered regularly interspaced short palindromic repeats as an advanced treatment for Parkinson's disease

Recently, genome-editing technology like clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 has improved the translational gap in the treatments mediated through gene therapy. The advantages of the CRISPR system, such as, work in the living cells and tissues, candidate this technique for the employing in experiments and the therapy of central nervous system diseases. Parkinson's disease (PD) is a widespread, disabling, neurodegenerative disease induced by dopaminergic neuron loss and linked to progressive motor impairment. Pathophysiological basis knowledge of PD has modified the PD classification model and expresses in the sporadic and familial types. Analyses of the earliest genetic linkage have shown in PD the inclusion of synuclein alpha (SNCA) genomic duplication and SNCA mutations in the familial types of PD pathogenesis. This review analyzes the structure, development, and function in genome editing regulated through the CRISPR/Cas9. Also, it explains the genes associated with PD pathogenesis and the appropriate modifications to favor PD. This study follows the direction by understanding the PD linking analyses in which the CRISPR technique is applied. Finally, this study explains the limitations and future trends of CRISPR service in relation to the genome-editing process in PD patients' induced pluripotent stem cells.

A cassava common mosaic virus vector for virus-induced gene silencing in cassava

BACKGROUND

Cassava is an important crop for food security and industry in the least-developed and developing countries. The completion of the cassava genome sequence and identification of large numbers of candidate genes by next-generation sequencing provide extensive resources for cassava molecular breeding and increase the need for rapid and efficient gene function analysis systems in cassava. Several plant virus-induced gene silencing (VIGS) systems have been developed as reverse genetic tools for rapid gene function analysis in cassava. However, these VIGS vectors could cause severe viral symptoms or inefficient gene silencing.

RESULTS

In this study, we constructed agroinfection-compatible infectious cDNA clones of cassava common mosaic virus isolate CM (CsCMV-CM, genus Potexvirus, family Alphaflexiviridae) that causes systemic infection with mild symptoms in cassava. CsCMV-CM was then modified to a viral vector carrying the Nimble cloning frame, which facilitates the rapid and high-throughput cloning of silencing fragments into the viral genome. The CsCMV-based vector successfully silenced phytoene desaturase (PDS) and magnesium chelatase subunit I (ChlI) in different cassava varieties and Nicotiana benthamiana. The silencing of the ChlI gene could persist for more than two months.

CONCLUSIONS

This CsCMV-based VIGS system provides a new tool for rapid and efficient gene function studies in cassava.

Caspase-7 deficiency in Chinese hamster ovary cells reduces cell proliferation and viability

BACKGROUND

Chinese hamster ovary (CHO) cells are the most commonly used mammalian host cell in the commercial-scale production of biopharmaceutical proteins. Modification of genes involved in apoptosis may improve the productivity of CHO cells. Executive caspases, including caspases 3 and 7, play critical roles in apoptosis. The effects of the ablation of the caspase 7 gene on proliferation and viability of CHO cells remains unknown. In this study, we applied clustered regularly interspaced short palindromic repeat (CRISPR/Cas9) to target caspase 7 gene of CHO K1 cell via all in one and homology targeted integration strategies. Consequently, the effect of caspase 7 deficiency on cell proliferation, viability, and apoptosis was studied by MTT assay and flow cytometry.

RESULTS

Findings of gel electrophoresis, western blotting, and sequencing confirmed the caspase 7 gene silencing in CHO cells (CHO-KO). Proliferation assay revealed that caspase 7 deficiency in CHO cells resulted in the reduction of proliferation in various CHO-KO clones. Besides, the disruption of caspase 7 had negative effects on cell viability in exposure with NaBu which confirmed by MTT assay. Results of flow cytometry using Anexin V/PI demonstrated that Nabu treatment (11 mM) declined the percentage of live CHO-K1 and CHO-KO cells to 70.3% and 5.79%. These results verified that the CHO-K1 cells were more resistant to apoptosis than CHO-KO, however most of CHO-KO cells undergone early apoptosis (91.9%) which seems to be a fascinating finding.

CONCLUSION

These results reveal that caspase 7 may be involved in the cell cycle progression of CHO cells. Furthermore, it seems that targeting caspase 7 is not the ideal route as it had previously been imagined within the prevention of apoptosis but the relation between caspase 7 deficiency, cell cycle arrest, and the occurrence of early apoptosis will require more investigation.

Multiplex Genome Editing in Chinese Hamster Ovary Cell Line Using All-in-One and HITI CRISPR Technology

Purpose: CRISPR/Cas9 gene editing technology has revolutionized gene manipulation by providing the opportunity of gene knock out/in, transcriptional modification and base editing. The application of this system extended into different eras of biology, from cell development to animal modeling. Various generations of CRISPR technology have been developed to make genome editing easy which resulted in rapid protocols for amelioration of a large genome.

Methods: We established a simple protocol for gene manipulation in Chinese hamster ovary (CHO) cells to achieve a Caspase 7 deficient cell line by using combination of all-in-one CRISPR technology and CRISPR/Cas9 homology-independent targeted integration (CRISPR HITI).

Results: the findings of this study indicated that using CRISPR knocking in/out technology facilitates genomic manipulation in CHO cells. Integration of EGFP in target locus of caspase 7 gene made the selection of knockout CHO cell line easy which achieved by cell sorting and single-cell cloning.

Conclusion: this system introduces an effective targeting strategy for multiplex genome engineering, coinciding gene integration which simplified the selection of desired genomic characteristics.

The interaction of phages and bacteria: the co-evolutionary arms race

Since the dawn of life, bacteria and phages are locked in a constant battle and both are perpetually changing their tactics to overcome each other. Bacteria use various strategies to overcome the invading phages, including adsorption inhibition, restriction-modification (R/E) systems, CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) systems, abortive infection (Abi), etc. To counteract, phages employ intelligent tactics for the nullification of bacterial defense systems, such as accessing host receptors, evading R/E systems, and anti-CRISPR proteins. Intense knowledge about the details of these defense pathways is the basis for their broad utilities in various fields of research from microbiology to biotechnology. Hence, in this review, we discuss some strategies used by bacteria to inhibit phage infections as well as phage tactics to circumvent bacterial defense systems. In addition, the application of these strategies will be described as a lesson learned from bacteria and phage combats. The ecological factors that affect the evolution of bacterial immune systems is the other issue represented in this review.

CRISPR System: A High-throughput Toolbox for Research and Treatment of Parkinson's Disease

In recent years, the innovation of gene-editing tools such as the CRISPR/Cas9 system improves the translational gap of treatments mediated by gene therapy. The privileges of CRISPR/Cas9 such as working in living cells and organs candidate this technology for using in research and treatment of the central nervous system (CNS) disorders. Parkinson's disease (PD) is a common, debilitating, neurodegenerative disorder which occurs due to loss of dopaminergic neurons and is associated with progressive motor dysfunction. Knowledge about the pathophysiological basis of PD has altered the classification system of PD, which manifests in familial and sporadic forms. The first genetic linkage studies in PD demonstrated the involvement of Synuclein alpha (SNCA) mutations and SNCA genomic duplications in the pathogenesis of PD familial forms. Subsequent studies have also insinuated mutations in leucine repeat kinase-2 (LRRK2), Parkin, PTEN-induced putative kinase 1 (PINK1), as well as DJ-1 causing familial forms of PD. This review will attempt to discuss the structure, function, and development in genome editing mediated by CRISP/Cas9 system. Further, it describes the genes involved in the pathogenesis of PD and the pertinent alterations to them. We will pursue this line by delineating the PD linkage studies in which CRISPR system was employed. Finally, we will discuss the pros and cons of CRISPR employment vis-à-vis the process of genome editing in PD patients' iPSCs.

CRISPR Cpf1 proteins: structure, function and implications for genome editing

CRISPR and CRISPR-associated (Cas) protein, as components of microbial adaptive immune system, allows biologists to edit genomic DNA in a precise and specific way. CRISPR-Cas systems are classified into two main classes and six types. Cpf1 is a putative type V (class II) CRISPR effector, which can be programmed with a CRISPR RNA to bind and cleave complementary DNA targets. Cpf1 has recently emerged as an alternative for Cas9, due to its distinct features such as the ability to target T-rich motifs, no need for trans-activating crRNA, inducing a staggered double-strand break and potential for both RNA processing and DNA nuclease activity. In this review, we attempt to discuss the evolutionary origins, basic architectures, and molecular mechanisms of Cpf1 family proteins, as well as crRNA designing and delivery strategies. We will also describe the novel Cpf1 variants, which have broadened the versatility and feasibility of this system in genome editing, transcription regulation, epigenetic modulation, and base editing. Finally, we will be reviewing the recent studies on utilization of Cpf1as a molecular tool for genome editing.