Extracellular Vesicles Loaded with Long Antisense RNAs Repress Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

Long antisense RNAs (asRNAs) have been observed to repress HIV and other virus expression in a manner that is refractory to viral evolution. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19) disease, has a distinct ability to evolve resistance around antibody targeting, as was evident from the emergence of various SARS-CoV-2 spike antibody variants. Importantly, the effectiveness of current antivirals is waning due to the rapid emergence of new variants of concern, more recently the omicron variant. One means of avoiding the emergence of viral resistance is by using long asRNA to target SARS-CoV-2. Similar work has proven successful with HIV targeting by long asRNA. In this study, we describe a long asRNA targeting SARS-CoV-2 RNA-dependent RNA polymerase gene and the ability to deliver this RNA in extracellular vesicles (EVs) to repress virus expression. The observations presented in this study suggest that EV-delivered asRNAs are one means to targeting SARS-CoV-2 infection, which is both effective and broadly applicable as a means to control viral expression in the absence of mutation. This is the first demonstration of the use of engineered EVs to deliver long asRNA payloads for antiviral therapy.

Targeting MAGI2-AS3-modulated Akt-dependent ATP-binding cassette transporters as a possible strategy to reverse temozolomide resistance in temozolomide-resistant glioblastoma cells.

Drug resistance is a major impediment to the successful treatment of glioma. This study aimed to elucidate the effects and mechanisms of the long noncoding RNA membrane-associated guanylate kinase inverted-2 antisense RNA 3 (MAGI2-AS3) on temozolomide (TMZ) resistance in glioma cells. MAGI2-AS3 expression in TMZ-resistant glioblastoma (GBM) cells was analyzed using the Gene Expression Omnibus data set GSE113510 and quantitative real-time PCR (qRT-PCR). Cell viability and TMZ half-maximal inhibitory concentration values were determined using the MTT assay. Apoptosis and cell cycle distribution were evaluated using flow cytometry. The expression of multidrug resistance 1 (MDR1), ATP-binding cassette superfamily G member 2 (ABCG2), protein kinase B (Akt), and phosphorylated Akt was detected using qRT-PCR and/or western blot analysis. MAGI2-AS3 was expressed at low levels in TMZ-resistant GBM cells relative to that in their parental cells. MAGI2-AS3 re-expression alleviated TMZ resistance in TMZ-resistant GBM cells. MAGI2-AS3 overexpression also accelerated TMZ-induced apoptosis and G2/M phase arrest. Mechanistically, MAGI2-AS3 overexpression reduced MDR1 and ABCG2 expression and inhibited the Akt pathway, whereas Akt overexpression abrogated the reduction in MDR1 and ABCG2 expression induced by MAGI2-AS3. Moreover, activation of the Akt pathway inhibited the effects of MAGI2-AS3 on TMZ resistance. MAGI2-AS3 inhibited tumor growth and enhanced the suppressive effect of TMZ on glioma tumorigenesis in vivo. In conclusion, MAGI2-AS3 reverses TMZ resistance in glioma cells by inactivating the Akt pathway.

Fulfilling the Promise of RNA Therapies for Cardiac Repair and Regeneration.

The progressive appreciation that multiple types of RNAs regulate virtually all aspects of tissue function and the availability of effective tools to deliver RNAs in vivo now offers unprecedented possibilities for obtaining RNA-based therapeutics. For the heart, RNA therapies can be developed that stimulate endogenous repair after cardiac damage. Applications in this area include acute cardioprotection after ischemia or cancer chemotherapy, therapeutic angiogenesis to promote new blood vessel formation, regeneration to form new cardiac mass, and editing of mutations to cure inherited cardiac disease. While the potential of RNA therapeutics for all these conditions is exciting, the field is still in its infancy. A number of roadblocks need to be overcome for RNA therapies to become effective, in particular, related to the problem of delivering RNA medicines into the cells and targeting them specifically to the heart.

Tetrahedral Framework Nucleic Acid Delivered RNA Therapeutics Significantly Attenuate Pancreatic Cancer Progression via Inhibition of CTR1-Dependent Copper Absorption.

Copper is vital for various life processes, whereas severely toxic at excess level. Intracellular copper homeostasis is strictly controlled by a set of transporters and chaperones encoded by the copper homeostasis genes. Increasing evidence has shown that copper is usually overloaded in multiple malignancies, including pancreatic cancer, which has an extremely poor prognosis. Recently, silencing the SLC31A1 gene, which encodes a major transmembrane copper transporter (CTR1), has been demonstrated to be an effective means for reducing the malignant degree of pancreatic cancer by downregulating the cellular copper levels. Herein, we utilized tetrahedral framework nucleic acids (tFNAs) as vehicles to overcome the biological barriers for delivering small molecular RNAs and efficiently transferred two kinds of CTR1 mRNA-targeted RNA therapeutics, siCTR1 or miR-124, into PANC-1 cells. Both therapeutic tFNAs, termed t-siCTR1 and t-miR-124, prevented copper intake more effective than the free RNA therapeutics via efficiently suppressing the expression of CTR1, thereby significantly attenuating the progression of PANC-1 cells. In this study, therapeutic tFNAs are constructed to target metal ion transporters for the first time, which may provide an effective strategy for future treatment of other metal metabolism disorders.

Emerging Gene and Small Molecule Therapies for the Neurodevelopmental Disorder Angelman Syndrome.

Angelman syndrome (AS) is a rare (~1:15,000) neurodevelopmental disorder characterized by severe developmental delay and intellectual disability, impaired communication skills, and a high prevalence of seizures, sleep disturbances, ataxia, motor deficits, and microcephaly. AS is caused by loss-of-function of the maternally inherited UBE3A gene. UBE3A is located on chromosome 15q11-13 and is biallelically expressed throughout the body but only maternally expressed in the brain due to an RNA antisense transcript that silences the paternal copy. There is currently no cure for AS, but advancements in small molecule drugs and gene therapies offer a promising approach for the treatment of the disorder. Here, we review AS and how loss-of-function of the maternal UBE3A contributes to the disorder. We also discuss the strengths and limitations of current animal models of AS. Furthermore, we examine potential small molecule drug and gene therapies for the treatment of AS and associated challenges faced by the therapeutic design. Finally, gene therapy offers the opportunity for precision medicine in AS and advancements in the treatment of this disorder can serve as a foundation for other single-gene neurodevelopmental disorders.

RNA Drugs and RNA Targets for Small Molecules: Principles, Progress, and Challenges.

RNA-based therapies, including RNA molecules as drugs and RNA-targeted small molecules, offer unique opportunities to expand the range of therapeutic targets. Various forms of RNAs may be used to selectively act on proteins, transcripts, and genes that cannot be targeted by conventional small molecules or proteins. Although development of RNA drugs faces unparalleled challenges, many strategies have been developed to improve RNA metabolic stability and intracellular delivery. A number of RNA drugs have been approved for medical use, including aptamers (e.g., pegaptanib) that mechanistically act on protein target and small interfering RNAs (e.g., patisiran and givosiran) and antisense oligonucleotides (e.g., inotersen and golodirsen) that directly interfere with RNA targets. Furthermore, guide RNAs are essential components of novel gene editing modalities, and mRNA therapeutics are under development for protein replacement therapy or vaccination, including those against unprecedented severe acute respiratory syndrome coronavirus pandemic. Moreover, functional RNAs or RNA motifs are highly structured to form binding pockets or clefts that are accessible by small molecules. Many natural, semisynthetic, or synthetic antibiotics (e.g., aminoglycosides, tetracyclines, macrolides, oxazolidinones, and phenicols) can directly bind to ribosomal RNAs to achieve the inhibition of bacterial infections. Therefore, there is growing interest in developing RNA-targeted small-molecule drugs amenable to oral administration, and some (e.g., risdiplam and branaplam) have entered clinical trials. Here, we review the pharmacology of novel RNA drugs and RNA-targeted small-molecule medications, with a focus on recent progresses and strategies. Challenges in the development of novel druggable RNA entities and identification of viable RNA targets and selective small-molecule binders are discussed. SIGNIFICANCE STATEMENT: With the understanding of RNA functions and critical roles in diseases, as well as the development of RNA-related technologies, there is growing interest in developing novel RNA-based therapeutics. This comprehensive review presents pharmacology of both RNA drugs and RNA-targeted small-molecule medications, focusing on novel mechanisms of action, the most recent progress, and existing challenges.

Long Non-Coding RNAs as Strategic Molecules to Augment the Radiation Therapy in Esophageal Squamous Cell Carcinoma.

Intrinsic resistance to ionizing radiation is the major impediment in the treatment and clinical management of esophageal squamous cell carcinoma (ESCC), leading to tumor relapse and poor prognosis. Although several biological and molecular mechanisms are responsible for resistance to radiotherapy in ESCC, the molecule(s) involved in predicting radiotherapy response and prognosis are still lacking, thus requiring a detailed understanding. Recent studies have demonstrated an imperative correlation amongst several long non-coding RNAs and their involvement in complex cellular networks like DNA damage and repair, cell cycle, apoptosis, proliferation, and epithelial-mesenchymal transition. Additionally, accumulating evidence has suggested abnormal expression of lncRNAs in malignant tumor cells before and after radiotherapy effects in tumor cells' sensitivity. Thus, lncRNAs indeed represent unique molecules that can influence tumor cell susceptibility for various clinical interventions. On this note, herein, we have summarized the current status of lncRNAs in augmenting resistance/sensitivity in ESCC against radiotherapy. In addition, we have also discussed various strategies to increase the radiosensitivity in ESCC cells under clinical settings.

Resolution of coronavirus disease 2019 (COVID-19).

INTRODUCTION: Coronavirus disease 2019 (COVID-19) was first detected in China in December, 2019, and declared as a pandemic by the World Health Organization (WHO) on March 11, 2020. The current management of COVID-19 is based generally on supportive therapy and treatment to prevent respiratory failure. The effective option of antiviral therapy and vaccination are currently under evaluation and development. AREAS COVERED: A literature search was performed using PubMed between December 1, 2019-June 23, 2020. This review highlights the current state of knowledge on the viral replication and pathogenicity, diagnostic and therapeutic strategies, and management of COVID-19. This review will be of interest to scientists and clinicians and make a significant contribution toward development of vaccines and targeted therapies to contain the pandemic. EXPERT OPINION: The exit strategy for a path back to normal life is required, which should involve a multi-prong effort toward development of new treatment and a successful vaccine to protect public health worldwide and prevent future COVID-19 outbreaks. Therefore, the bench to bedside translational research as well as reverse translational works focusing bedside to bench is very important and would provide the foundation for the development of targeted drugs and vaccines for COVID-19 infections.

RNA-based pharmacotherapy for tumors: From bench to clinic and back.

RNA therapy is a treatment that regulates cell proteins and cures diseases by affecting the metabolism of mRNAs in cells, which has cut a figure in the studies on various incurable illnesses like hereditary diseases, tumors, etc. In this review, we introduced the discovery and development of RNA therapy and discussed its classification, mechanisms, advantages, and challenges. Moreover, we highlighted how RNA therapy works in killing tumor cells as well as what progresses it has made in related researches. And the development of RNA anti-tumor drugs and the clinical trial process were also included.

A Self-Assembled Platform Based on Branched DNA for sgRNA/Cas9/Antisense Delivery.

Precisely assembled DNA nanostructures are promising candidates for the delivery of biomolecule-based therapeutics. Herein, we introduce a facile strategy for the construction of a branched DNA-based nanoplatform for codelivery of gene editing (sgRNA/Cas9, targeting DNA in the nucleus) and gene silencing (antisense, targeting mRNA in the cytoplasm) components for synergistic tumor therapy in vitro and in vivo. In our design, the branched DNA structure can efficiently load a sgRNA/Cas9/antisense complex targeting a tumor-associated gene, PLK1, through DNA self-assembly. With the incorporation of an active targeting aptamer and an endosomal escape peptide by host-guest interaction, the biocompatible DNA nanoplatform demonstrates efficient inhibition of tumor growth without apparent systemic toxicity. This multifunctional DNA nanocarrier provides a new strategy for the development of gene therapeutics.

Rationally designing antisense therapy to keep up with evolving bacterial resistance.

Antisense molecules used as antibiotics offer the potential to keep up with acquired resistance, by redesigning the sequence of an antisense. Once bacteria acquire resistance by mutating the targeted sequence, new antisense can readily be designed by using sequence information of a target gene. However, antisense molecules require additional delivery vehicles to get into bacteria and be protected from degradation. Based on progress in the last few years it appears that, while redesigning or finding new delivery vehicle will be more difficult than redesigning the antisense cargo, it will perhaps be less difficult than finding new conventional small molecule antibiotics. In this study we propose a protocol that maximizes the combined advantages of engineered delivery vehicle and antisense cargo by decreasing the immediate growth advantage to the pathogen of mutating the entry mechanisms and increasing the advantage to the pathogen of antisense target mutations. Using this protocol, we show by computer simulation an appropriately designed antisense therapy can potentially be effective many times longer than conventional antibiotics before succumbing to resistance. While the simulations describe an in-vitro situation, based on comparison with other in-vitro studies on acquired resistance we believe the advantages of the combination antisense strategy have the potential to provide much more sustainability in vivo than conventional antibiotic therapy.

Exon-skipping advances for Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a fatal genetic disorder characterized by progressive muscle wasting that has currently no cure. Exon-skipping strategy represents one of the most promising therapeutic approaches that aim to restore expression of a shorter but functional dystrophin protein. The antisense field has remarkably progress over the last years with recent accelerated approval of the first antisense oligonucleotide-based therapy for DMD, Exondys 51, though the therapeutic benefit remains to be proved in patients. Despite clinical advances, the poor effective delivery to target all muscle remains the main hurdle for antisense drug therapy. This review describes the antisense-based exon-skipping approach for DMD, from proof-of-concept to first marketed drug. We discuss the main obstacles to achieve a successful exon-skipping therapy and the latest advances of the international community to develop more powerful chemistries and more sophisticated delivery systems in order to increase potency, bioavailability and safety. Finally, we highlight the importance of collaborative efforts and early dialogue between drug developers and regulatory agencies in order to overcome difficulties, find appropriate outcome markers and collect useful data.

New drugs for the treatment of Mycobacterium tuberculosis infection.

Tuberculosis presents a grave challenge to health, globally instigating 1.5 million mortalities each year. Following the breakthrough of first-line anti-TB medication, the number of mortalities reduced greatly; nonetheless, the swift appearance of tuberculosis which was drug-resistant, as well as the capability of the bacterium to survive and stay dormant are a considerable problem for public health. In order to address this issue, several novel possible candidates for tuberculosis therapy have been subjected to clinical trials of late. The novel antimycobacterial agents are acquired from different categories of medications, operate through a range of action systems, and are at various phases of advancement. We therefore talk about the present methods of treating tuberculosis and novel anti-TB agents with their action method, in order to advance awareness of these new compounds and medications.

Myotonic dystrophy: approach to therapy.

Myotonic dystrophy (DM) is a dominantly-inherited genetic disorder affecting skeletal muscle, heart, brain, and other organs. DM type 1 is caused by expansion of a CTG triplet repeat in DMPK, whereas DM type 2 is caused by expansion of a CCTG tetramer repeat in CNBP. In both cases the DM mutations lead to expression of dominant-acting RNAs. Studies of RNA toxicity have now revealed novel mechanisms and new therapeutic targets. Preclinical data have suggested that RNA dominance is responsive to therapeutic intervention and that DM therapy can be approached at several different levels. Here we review recent efforts to alleviate RNA toxicity in DM.

The notorious R.N.A. in the spotlight - drug or target for the treatment of disease.

mRNA is an attractive drug target for therapeutic interventions. In this review we highlight the current state, clinical trials, and developments in antisense therapy, including the classical approaches like RNaseH-dependent oligomers, splice-switching oligomers, aptamers, and therapeutic RNA interference. Furthermore, we provide an overview on emerging concepts for using RNA in therapeutic settings including protein replacement by in-vitro-transcribed mRNAs, mRNA as vaccines and anti-allergic drugs. Finally, we give a brief outlook on early-stage RNA repair approaches that apply endogenous or engineered proteins in combination with short RNAs or chemically stabilized oligomers for the re-programming of point mutations, RNA modifications, and frame shift mutations directly on the endogenous mRNA.

Stacking up CRISPR against RNAi for therapeutic gene inhibition.

Both RNA interference (RNAi) and clustered regularly-interspaced short palindromic repeats (CRISPR) technologies allow for the sequence-specific inhibition of gene function and therefore have the potential to be used as therapeutic modalities. By judging the current public and scientific journal interest, it would seem that CRISPR, by enabling clean, durable knockouts, will dominate therapeutic gene inhibition, also at the expense of RNAi. This review aims to look behind prevailing sentiments and to more clearly define the likely scope of the therapeutic applications of the more recently developed CRISPR technology and its relative strengths and weaknesses with regards to RNAi. It is found that largely because of their broadly overlapping delivery constraints, while CRISPR presents formidable competition for DNA-directed RNAi strategies, its impact on RNAi therapeutics triggered by synthetic oligonucleotides will likely be more moderate. Instead, RNAi and genome editing, and in particular CRISPR, are poised to jointly promote a further shift toward sequence-targeted precision medicines.

The first crystal structures of RNA-PNA duplexes and a PNA-PNA duplex containing mismatches--toward anti-sense therapy against TREDs.

PNA is a promising molecule for antisense therapy of trinucleotide repeat disorders. We present the first crystal structures of RNA-PNA duplexes. They contain CUG repeats, relevant to myotonic dystrophy type I, and CAG repeats associated with poly-glutamine diseases. We also report the first PNA-PNA duplex containing mismatches. A comparison of the PNA homoduplex and the PNA-RNA heteroduplexes reveals PNA's intrinsic structural properties, shedding light on its reported sequence selectivity or intolerance of mismatches when it interacts with nucleic acids. PNA has a much lower helical twist than RNA and the resulting duplex has an intermediate conformation. PNA retains its overall conformation while locally there is much disorder, especially peptide bond flipping. In addition to the Watson-Crick pairing, the structures contain interesting interactions between the RNA's phosphate groups and the Π electrons of the peptide bonds in PNA.