Progresses on RNA-based therapeutics for genetic diseases / 浙江大学学报·医学版

RNA therapeutics inhibit the expression of specific proteins/RNAs by targeting complementary sequences of corresponding genes, or synthesize proteins encoded by the desired genes to treat genetic diseases. RNA-based therapeutics are categorized as oligonucleotide drugs (antisense oligonucleotides, small interfering RNA, RNA aptamers), and mRNA drugs. The antisense oligonucleotides and small interfering RNA for treatment of genetic diseases have been approved by the FDA in the United State, while RNA aptamers and mRNA drugs are still in clinical trials. Chemical modifications are applied to RNA drugs, such as pseudouridine modification of mRNA, to reduce immunogenicity and improve the efficacy. The secure and effective delivery systems like lipid-based nanoparticles, extracellular vesicles, and virus-like particles are under development to address stability, specificity, and safety issues of RNA drugs. This article provides an overview of the specific molecular mechanisms of 11 RNA drugs currently used for treating genetic diseases, and discusses the research progress of chemical modifications and delivery systems of RNA drugs.

Progress on RNA-based therapeutics for genetic diseases / 浙江大学学报·医学版

RNA therapeutics inhibit the expression of specific proteins/RNAs by targeting complementary sequences of corresponding genes or encode proteins for the synthesis desired genes to treat genetic diseases. RNA-based therapeutics are categorized as oligonucleotide drugs (antisense oligonucleotides, small interfering RNA, RNA aptamers), and mRNA drugs. The antisense oligonucleotides and small interfering RNA for treatment of genetic diseases have been approved by the FDA in the United States, while RNA aptamers and mRNA drugs are still in clinical trials. Chemical modifications can be applied to RNA drugs, such as pseudouridine modification of mRNA, to reduce immunogenicity and improve the efficacy. The secure and effective delivery systems such as lipid-based nanoparticles, extracellular vesicles, and virus-like particles are under development to address stability, specificity, and safety issues of RNA drugs. This article provides an overview of the specific molecular mechanisms of eleven RNA drugs currently used for treating genetic diseases, and discusses the research progress of chemical modifications and delivery systems of RNA drugs.

Evolution of specific RNA aptamers via SELEX targeting recombinant human CD36 protein: A candidate therapeutic target in severe malaria

Objective: To isolate and characterize RNA aptamers that are specific to human CD36 protein using systematic evolution of ligands by exponential enrichment (SELEX) technology to identify candidates for adjunct therapy to reverse the binding of Plasmodium-infected erythrocytes. Methods: RNA aptamers were isolated using nitrocellulose membrane-based SELEX and binding analysis was screened using an electrophoretic mobility shift assay and enzyme-linked oligonucleotide assay. Results: Thirteen cycles of nitrocellulose membrane-based SELEX yielded three aptamers (RC60, RC25, RC04) exhibiting high binding against CD36 protein as shown on electrophoretic mobility shift assay. The sequence analysis revealed a G-quadruplex sequence within all the isolated aptamers that might contribute to aptamer binding and thermodynamic stability. The specificity assay further showed that RC60 and RC25 were highly specific to CD36. The competitive inhibition assay demonstrated that RC60 and RC25 shared a similar binding epitope recognized by mAb FA6-152, a specific monoclonal antibody against CD36. Conclusions: RC60 and RC25 are promising candidates as anti-cytoadherence for severe malaria adjunct therapy.

Evolution of specific RNA aptamers via SELEX targeting recombinant human CD36 protein: A candidate therapeutic target in severe malaria

To isolate and characterize RNA aptamers that are specific to human CD36 protein using systematic evolution of ligands by exponential enrichment (SELEX) technology to identify candidates for adjunct therapy to reverse the binding of Plasmodiuminfected erythrocytes. Methods: RNA aptamers were isolated using nitrocellulose membrane-based SELEX and binding analysis was screened using an electrophoretic mobility shift assay and enzyme-linked oligonucleotide assay. Results: Thirteen cycles of nitrocellulose membrane-based SELEX yielded three aptamers (RC60, RC25, RC04) exhibiting high binding against CD36 protein as shown on electrophoretic mobility shift assay. The sequence analysis revealed a G-quadruplex sequence within all the isolated aptamers that might contribute to aptamer binding and thermodynamic stability. The specificity assay further showed that RC60 and RC25 were highly specific to CD36. The competitive inhibition assay demonstrated that RC60 and RC25 shared a similar binding epitope recognized by mAb FA6-152, a specific monoclonal antibody against CD36. Conclusions: RC60 and RC25 are promising candidates as anticytoadherence for severe malaria adjunct therapy.

Mechanism-based design of 2,3-benzodiazepine inhibitors for AMPA receptors

2,3-Benzodiazepine (2,3-BDZ) compounds represent a group of structurally diverse, small-molecule antagonists of (R, S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptors. Antagonists of AMPA receptors are drug candidates for potential treatment of a number of neurological disorders such as epilepsy, stroke and amyotrophic lateral sclerosis (ALS). How to make better inhibitors, such as 2,3-BDZs, has been an enduring quest in drug discovery. Among a few available tools to address this specific question for making better 2,3-BDZs, perhaps the best one is to use mechanistic clues from studies of the existing antagonists to design and discover more selective and more potent antagonists. Here I review recent work in this area, and propose some ideas in the continuing effort of developing newer 2,3-BDZs for tighter control of AMPA receptor activities in vivo.

First report of in vitro selection of RNA aptamers targeted to recombinant Loxosceles laeta spider toxins

BACKGROUND: Loxoscelism is the envenomation caused by the bite of Loxosceles spp. spiders. It entails severe necrotizing skin lesions, sometimes accompanied by systemic reactions and even death. There are no diagnostic means and treatment is mostly palliative. The main toxin, found in several isoforms in the venom, is sphingomyelinase D (SMD), a phospholipase that has been used to generate antibodies intended for medical applications. Nucleic acid aptamers are a promising alternative to antibodies. Aptamers may be isolated from a combinatorial mixture of oligonucleotides by iterative selection of those that bind to the target. In this work, two Loxosceles laeta SMD isoforms, Ll1 and Ll2, were produced in bacteria and used as targets with the aim of identifying RNA aptamers that inhibit sphingomyelinase activity. RESULTS: Six RNA aptamers capable of eliciting partial but statistically significant inhibitions of the sphingomyelinase activity of recombinant SMD-Ll1 and SMD-Ll2 were obtained: four aptamers exert ~17% inhibition of SMD-Ll1, while two aptamers result in ~25% inhibition of SMD-Ll2 and ~18% cross inhibition of SMD-Ll1. CONCLUSIONS: This work is the first attempt to obtain aptamers with therapeutic and diagnostic potential for loxoscelism and provides an initial platform to undertake the development of novel anti Loxoscelesvenom agents.

Massive Identification of Cancer-Specific Nucleic Acid Ligands

Targeting of complex system such as human cells rather than biochemically pure molecules will be a useful approach to massively identify ligands specific for the markers associated with human disease such as cancer and simultaneously discover the specific molecular markers. In this study, we developed in vitro selection method to identify nuclease-resistant nucleic acid ligands called RNA aptamers that are specific for human cancer cells. This method is based on the combination of the cell-based selection and subtractive systematic evolution of ligands by exponential enrichment (SELEX) method. These aptamers will be useful for cancer-specific ligands for proteomic research to identify cancer-specific molecular markers as well as tumor diagnosis and therapy.