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In the past several decades, there has been an increased appreciation of RNA modifications and their biological functions. In this issue of Cell, Flynn et al. describe the discovery of glycoRNAs present on the surface of cells. Like proteins and lipids, conserved non-coding RNAs are functionalized with carbohydrates.
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Target occupancy is often insufficient to elicit biological activity, particularly for RNA, compounded by the longstanding challenges surrounding the molecular recognition of RNA structures by small molecules. Here we studied molecular recognition patterns between a natural-product-inspired small-molecule collection and three-dimensionally folded RNA structures. Mapping these interaction landscapes across the human transcriptome defined structure-activity relationships. Although RNA-binding compounds that bind to functional sites were expected to elicit a biological response, most identified interactions were predicted to be biologically inert as they bind elsewhere. We reasoned that, for such cases, an alternative strategy to modulate RNA biology is to cleave the target through a ribonuclease-targeting chimera, where an RNA-binding molecule is appended to a heterocycle that binds to and locally activates RNase L1. Overlay of the substrate specificity for RNase L with the binding landscape of small molecules revealed many favourable candidate binders that might be bioactive when converted into degraders. We provide a proof of concept, designing selective degraders for the precursor to the disease-associated microRNA-155 (pre-miR-155), JUN mRNA and MYC mRNA. Thus, small-molecule RNA-targeted degradation can be leveraged to convert strong, yet inactive, binding interactions into potent and specific modulators of RNA function.
Assuntos
Endorribonucleases , MicroRNAs , RNA Mensageiro , Humanos , Genes jun/genética , Genes myc/genética , MicroRNAs/antagonistas & inibidores , MicroRNAs/química , MicroRNAs/genética , MicroRNAs/metabolismo , Conformação de Ácido Nucleico , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Relação Estrutura-Atividade , Especificidade por Substrato , Endorribonucleases/química , Endorribonucleases/metabolismo , TranscriptomaRESUMO
α-Synuclein is an important drug target for the treatment of Parkinson's disease (PD), but it is an intrinsically disordered protein lacking typical small-molecule binding pockets. In contrast, the encoding SNCA mRNA has regions of ordered structure in its 5' untranslated region (UTR). Here, we present an integrated approach to identify small molecules that bind this structured region and inhibit α-synuclein translation. A drug-like, RNA-focused compound collection was studied for binding to the 5' UTR of SNCA mRNA, affording Synucleozid-2.0, a drug-like small molecule that decreases α-synuclein levels by inhibiting ribosomes from assembling onto SNCA mRNA. This RNA-binding small molecule was converted into a ribonuclease-targeting chimera (RiboTAC) to degrade cellular SNCA mRNA. RNA-seq and proteomics studies demonstrated that the RiboTAC (Syn-RiboTAC) selectively degraded SNCA mRNA to reduce its protein levels, affording a fivefold enhancement of cytoprotective effects as compared to Synucleozid-2.0. As observed in many diseases, transcriptome-wide changes in RNA expression are observed in PD. Syn-RiboTAC also rescued the expression of ~50% of genes that were abnormally expressed in dopaminergic neurons differentiated from PD patient-derived iPSCs. These studies demonstrate that the druggability of the proteome can be expanded greatly by targeting the encoding mRNAs with both small molecule binders and RiboTAC degraders.
Assuntos
Proteínas Intrinsicamente Desordenadas , Doença de Parkinson , Humanos , alfa-Sinucleína/genética , RNA Mensageiro/genética , Proteínas Intrinsicamente Desordenadas/genética , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/genética , Regiões 5' não Traduzidas , RibonucleasesRESUMO
G4C2 and G2C4 repeat expansions in chromosome 9 open reading frame 72 (C9orf72) are the most common cause of genetically defined amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), or c9ALS/FTD. The gene is bidirectionally transcribed, producing G4C2 repeats [r(G4C2)exp] and G2C4 repeats [r(G2C4)exp]. The c9ALS/FTD repeat expansions are highly structured, and structural studies showed that r(G4C2)exp predominantly folds into a hairpin with a periodic array of 1 × 1 G/G internal loops and a G-quadruplex. A small molecule probe revealed that r(G4C2)exp also adopts a hairpin structure with 2 × 2 GG/GG internal loops. We studied the conformational dynamics adopted by 2 × 2 GG/GG loops using temperature replica exchange molecular dynamics (T-REMD) and further characterized the structure and underlying dynamics using traditional 2D NMR techniques. These studies showed that the loop's closing base pairs influence both structure and dynamics, particularly the configuration adopted around the glycosidic bond. Interestingly, r(G2C4) repeats, which fold into an array of 2 × 2 CC/CC internal loops, are not as dynamic. Collectively, these studies emphasize the unique sensitivity of r(G4C2)exp to small changes in stacking interactions, which is not observed in r(G2C4)exp, providing important considerations for further principles in structure-based drug design.
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Esclerose Lateral Amiotrófica , Proteína C9orf72 , Demência Frontotemporal , Humanos , Esclerose Lateral Amiotrófica/genética , Proteína C9orf72/genética , Expansão das Repetições de DNA , Demência Frontotemporal/genética , Espectroscopia de Ressonância Magnética , Simulação de Dinâmica Molecular , RNARESUMO
Nature evolves molecular interaction networks through persistent perturbation and selection, in stark contrast to drug discovery, which evaluates candidates one at a time by screening. Here, nature's highly parallel ligand-target search paradigm is recapitulated in a screen of a DNA-encoded library (DEL; 73,728 ligands) against a library of RNA structures (4,096 targets). In total, the screen evaluated â¼300 million interactions and identified numerous bona fide ligand-RNA three-dimensional fold target pairs. One of the discovered ligands bound a 5'GAG/3'CCC internal loop that is present in primary microRNA-27a (pri-miR-27a), the oncogenic precursor of microRNA-27a. The DEL-derived pri-miR-27a ligand was cell active, potently and selectively inhibiting pri-miR-27a processing to reprogram gene expression and halt an otherwise invasive phenotype in triple-negative breast cancer cells. By exploiting evolutionary principles at the earliest stages of drug discovery, it is possible to identify high-affinity and selective target-ligand interactions and predict engagements in cells that short circuit disease pathways in preclinical disease models.
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DNA/genética , RNA não Traduzido/genética , Carcinogênese/efeitos dos fármacos , Carcinogênese/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Descoberta de Drogas/métodos , Expressão Gênica/genética , Biblioteca Gênica , Humanos , Ligantes , MicroRNAs/genética , Oncogenes/genética , Bibliotecas de Moléculas Pequenas/farmacologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genéticaRESUMO
A hexanucleotide repeat expansion in intron 1 of the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia, or c9ALS/FTD. The RNA transcribed from the expansion, r(G4C2)exp, causes various pathologies, including intron retention, aberrant translation that produces toxic dipeptide repeat proteins (DPRs), and sequestration of RNA-binding proteins (RBPs) in RNA foci. Here, we describe a small molecule that potently and selectively interacts with r(G4C2)exp and mitigates disease pathologies in spinal neurons differentiated from c9ALS patient-derived induced pluripotent stem cells (iPSCs) and in two c9ALS/FTD mouse models. These studies reveal a mode of action whereby a small molecule diminishes intron retention caused by the r(G4C2)exp and allows the liberated intron to be eliminated by the nuclear RNA exosome, a multi-subunit degradation complex. Our findings highlight the complexity of mechanisms available to RNA-binding small molecules to alleviate disease pathologies and establishes a pipeline for the design of brain penetrant small molecules targeting RNA with novel modes of action in vivo.
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Exossomos , Demência Frontotemporal , Animais , Camundongos , Demência Frontotemporal/metabolismo , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , RNA/genética , Exossomos/metabolismo , Barreira Hematoencefálica/metabolismo , Complexo Multienzimático de Ribonucleases do Exossomo/metabolismo , Encéfalo/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , RNA NuclearRESUMO
Various approaches have been developed to target RNA and modulate its function with modes of action including binding and cleavage. Herein, we explored how small molecule binding is correlated with cleavage induced by heterobifunctional ribonuclease targeting chimeras (RiboTACs), where RNase L is recruited to cleave the bound RNA target, in a transcriptome-wide, unbiased fashion. Only a fraction of bound targets was cleaved by RNase L, induced by RiboTAC binding. Global analysis suggested that (i) cleaved targets generally form a region of stable structure that encompasses the small molecule binding site; (ii) cleaved targets have preferred RNase L cleavage sites nearby small molecule binding sites; (iii) RiboTACs facilitate a cellular interaction between cleaved targets and RNase L; and (iv) the expression level of the target influences the extent of cleavage observed. In one example, we converted a binder of LGALS1 (galectin-1) mRNA into a RiboTAC. In MDA-MB-231 cells, the binder had no effect on galectin-1 protein levels, while the RiboTAC cleaved LGALS1 mRNA, reduced galectin-1 protein abundance, and affected galectin-1-associated oncogenic cellular phenotypes. Using LGALS1, we further assessed additional factors including the length of the linker that tethers the two components of the RiboTAC, cellular uptake, and the RNase L-recruiting module on RiboTAC potency. Collectively, these studies may facilitate triangulation of factors to enable the design of RiboTACs.
Assuntos
Transcriptoma , Humanos , Linhagem Celular Tumoral , Endorribonucleases/metabolismo , Endorribonucleases/química , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Ribonucleases/metabolismo , Ribonucleases/químicaRESUMO
Trinucleotide repeat expansions fold into long, stable hairpins and cause a variety of incurable RNA gain-of-function diseases such as Huntington's disease, the myotonic dystrophies, and spinocerebellar ataxias. One approach for treating these diseases is to bind small molecules to these structured RNAs. Both Huntington's disease-like 2 (HDL2) and myotonic dystrophy type 1 (DM1) are caused by a r(CUG) repeat expansion, or r(CUG)exp. The RNA folds into a hairpin structure with a periodic array of 1 × 1 nucleotide UU loops (5'CUG/3'GUC; where the underlined nucleotides indicate the Us in the internal loop) that sequester various RNA-binding proteins (RBPs) and hence the source of its gain-of-function. Here, we report nuclear magnetic resonance (NMR)-refined structures of single 5'CUG/3'GUC motifs in complex with three different small molecules, a di-guandinobenzoate (1), a derivative of 1 where the guanidino groups have been exchanged for imidazole (2), and a quinoline with improved drug-like properties (3). These structures were determined using NMR spectroscopy and simulated annealing with restrained molecular dynamics (MD). Compounds 1, 2, and 3 formed stacking and hydrogen bonding interactions with the 5'CUG/3'GUC motif. Compound 3 also formed van der Waals interactions with the internal loop. The global structure of each RNA-small molecule complexes retains an A-form conformation, while the internal loops are still dynamic but to a lesser extent compared to the unbound form. These results aid our understanding of ligand-RNA interactions and enable structure-based design of small molecules with improved binding affinity for and biological activity against r(CUG)exp. As the first ever reported structures of a r(CUG) repeat bound to ligands, these structures can enable virtual screening campaigns combined with machine learning assisted de novo design.
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Fragile X-associated tremor and ataxia syndrome (FXTAS) is a late-onset, progressive neurodegenerative disorder characterized by tremors, ataxia and neuropsychological problems. This disease is quite common in the general population with approximately 20 million carriers worldwide. The risk of developing FXTAS increases dramatically with age, with about 45% of male carriers over the age of 50 being affected. FXTAS is caused by a CGG-repeat expansion (CGGexp) in the fragile X mental retardation 1 (FMR1) gene. CGGexp RNA is translated into the FMRpolyG protein by a mechanism called RAN translation. Although both gene and pathogenic trigger are known, no therapeutic interventions are available at this moment. Here, we present, for the first time, primary hippocampal neurons derived from the ubiquitous inducible mouse model which is used as a screening tool for targeted interventions. A promising candidate is the repeat binding, RAN translation blocking, small molecule 1a. Small molecule 1a shields the disease-causing CGGexp from being translated into the toxic FMRpolyG protein. Primary hippocampal neurons formed FMRpolyG-positive inclusions, and upon treatment with 1a, the numbers of FMRpolyG-positive inclusions are reduced. We also describe for the first time the formation of FMRpolyG-positive inclusions in the liver of this mouse model. Treatment with 1a reduced the insoluble FMRpolyG protein fraction in the liver but not the number of inclusions. Moreover, 1a treatment had a reducing effect on the number of Rad23b-positive inclusions and insoluble Rad23b protein levels. These data suggest that targeted small molecule therapy is effective in an FXTAS mouse model and has the potential to treat CGGexp-mediated diseases, including FXTAS.
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Ataxia/genética , Proteína do X Frágil da Deficiência Intelectual/genética , Síndrome do Cromossomo X Frágil/genética , Tremor/genética , Animais , Ataxia/fisiopatologia , Comunicação Celular , Enzimas Reparadoras do DNA/genética , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Síndrome do Cromossomo X Frágil/fisiopatologia , Humanos , Masculino , Camundongos , Neurônios/metabolismo , Tremor/fisiopatologia , Expansão das Repetições de TrinucleotídeosRESUMO
RNAs have important functions that are dictated by their structure. Indeed, small molecules that interact with RNA structures can perturb function, serving as chemical probes and lead medicines. Here we describe the development of a fragment-based approach to discover and optimize bioactive small molecules targeting RNA. We extended the target validation method chemical cross-linking and isolation by pull-down (Chem-CLIP) to identify and map the binding sites of low molecular weight fragments that engage RNA or Chem-CLIP fragment mapping (Chem-CLIP-Frag-Map). Using Chem-CLIP-Frag-Map, we identified several fragments that bind the precursor to oncogenic microRNA-21 (pre-miR-21). Assembly of these fragments provided a specific bioactive compound with improved potency that inhibits pre-miR-21 processing, reducing mature miR-21 levels. The compound exerted selective effects on the transcriptome and selectively mitigated a miR-21-associated invasive phenotype in triple-negative breast cancer cells. The Chem-CLIP-Frag-Map approach should prove general to expedite the identification and optimization of small molecules that bind RNA targets.
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Antineoplásicos/química , Descoberta de Drogas/métodos , MicroRNAs/química , Bibliotecas de Moléculas Pequenas/química , Antineoplásicos/farmacologia , Linhagem Celular , Linhagem Celular Tumoral , Feminino , Humanos , Ligantes , MicroRNAs/metabolismo , Simulação de Acoplamento Molecular , Motivos de Nucleotídeos , Bibliotecas de Moléculas Pequenas/farmacologia , Neoplasias de Mama Triplo Negativas/metabolismoRESUMO
Many proteins are refractory to targeting because they lack small-molecule binding pockets. An alternative to drugging these proteins directly is to target the messenger (m)RNA that encodes them, thereby reducing protein levels. We describe such an approach for the difficult-to-target protein α-synuclein encoded by the SNCA gene. Multiplication of the SNCA gene locus causes dominantly inherited Parkinson's disease (PD), and α-synuclein protein aggregates in Lewy bodies and Lewy neurites in sporadic PD. Thus, reducing the expression of α-synuclein protein is expected to have therapeutic value. Fortuitously, the SNCA mRNA has a structured iron-responsive element (IRE) in its 5' untranslated region (5' UTR) that controls its translation. Using sequence-based design, we discovered small molecules that target the IRE structure and inhibit SNCA translation in cells, the most potent of which is named Synucleozid. Both in vitro and cellular profiling studies showed Synucleozid directly targets the α-synuclein mRNA 5' UTR at the designed site. Mechanistic studies revealed that Synucleozid reduces α-synuclein protein levels by decreasing the amount of SNCA mRNA loaded into polysomes, mechanistically providing a cytoprotective effect in cells. Proteome- and transcriptome-wide studies showed that the compound's selectivity makes Synucleozid suitable for further development. Importantly, transcriptome-wide analysis of mRNAs that encode intrinsically disordered proteins revealed that each has structured regions that could be targeted with small molecules. These findings demonstrate the potential for targeting undruggable proteins at the level of their coding mRNAs. This approach, as applied to SNCA, is a promising disease-modifying therapeutic strategy for PD and other α-synucleinopathies.
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Proteínas Intrinsicamente Desordenadas/genética , Inibidores da Síntese de Proteínas/farmacologia , RNA Mensageiro/metabolismo , Elementos de Resposta , alfa-Sinucleína/genética , Regiões 3' não Traduzidas , Animais , Linhagem Celular Tumoral , Humanos , Proteínas Intrinsicamente Desordenadas/metabolismo , Camundongos , Biossíntese de Proteínas/efeitos dos fármacos , Inibidores da Síntese de Proteínas/química , RNA Mensageiro/química , RNA Mensageiro/genética , alfa-Sinucleína/metabolismoRESUMO
As the area of small molecules interacting with RNA advances, general routes to provide bioactive compounds are needed as ligands can bind RNA avidly to sites that will not affect function. Small-molecule targeted RNA degradation will thus provide a general route to affect RNA biology. A non-oligonucleotide-containing compound was designed from sequence to target the precursor to oncogenic microRNA-21 (pre-miR-21) for enzymatic destruction with selectivity that can exceed that for protein-targeted medicines. The compound specifically binds the target and contains a heterocycle that recruits and activates a ribonuclease to pre-miR-21 to substoichiometrically effect its cleavage and subsequently impede metastasis of breast cancer to lung in a mouse model. Transcriptomic and proteomic analyses demonstrate that the compound is potent and selective, specifically modulating oncogenic pathways. Thus, small molecules can be designed from sequence to have all of the functional repertoire of oligonucleotides, including inducing enzymatic degradation, and to selectively and potently modulate RNA function in vivo.
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Neoplasias da Mama/tratamento farmacológico , MicroRNAs/metabolismo , Ribonucleases/metabolismo , Bibliotecas de Moléculas Pequenas/uso terapêutico , Animais , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Desenho de Fármacos , Feminino , Humanos , Camundongos , MicroRNAs/química , Estrutura Molecular , Metástase Neoplásica , Oligonucleotídeos/química , Oligonucleotídeos/metabolismo , Ribonucleases/química , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/metabolismoRESUMO
RNA is challenging to target with bioactive small molecules, particularly those of low molecular weight that bind with sufficient affinity and specificity. In this report, we developed a platform to address this challenge, affording a novel bioactive interaction. An RNA-focused small-molecule fragment collection (n = 2500) was constructed by analyzing features in all publicly reported compounds that bind RNA, the largest collection of RNA-focused fragments to date. The RNA-binding landscape for each fragment was studied by using a library-versus-library selection with an RNA library displaying a discrete structural element, probing over 12.8 million interactions, the greatest number of interactions between fragments and biomolecules probed experimentally. Mining of this dataset across the human transcriptome defined a drug-like fragment that potently and specifically targeted the microRNA-372 hairpin precursor, inhibiting its processing into the mature, functional microRNA and alleviating invasive and proliferative oncogenic phenotypes in gastric cancer cells. Importantly, this fragment has favorable properties, including an affinity for the RNA target of 300 ± 130 nM, a molecular weight of 273 Da, and quantitative estimate of drug-likeness (QED) score of 0.8. (For comparison, the mean QED of oral medicines is 0.6 ± 0.2). Thus, these studies demonstrate that a low-molecular weight, fragment-like compound can specifically and potently modulate RNA targets.
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MicroRNAs , Bibliotecas de Moléculas Pequenas , Humanos , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/química , Peso Molecular , MicroRNAs/metabolismo , CarcinogêneseRESUMO
A solid-phase DNA-encoded library (DEL) was studied for binding the RNA repeat expansion r(CUG)exp, the causative agent of the most common form of adult-onset muscular dystrophy, myotonic dystrophy type 1 (DM1). A variety of uncharged and novel RNA binders were identified to selectively bind r(CUG)exp by using a two-color flow cytometry screen. The cellular activity of one binder was augmented by attaching it with a module that directly cleaves r(CUG)exp. In DM1 patient-derived muscle cells, the compound specifically bound r(CUG)exp and allele-specifically eliminated r(CUG)exp, improving disease-associated defects. The approaches herein can be used to identify and optimize ligands and bind RNA that can be further augmented for functionality including degradation.
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DNA , Biblioteca Gênica , Distrofia Miotônica , Estabilidade de RNA , RNA , Expansão das Repetições de Trinucleotídeos , Humanos , DNA/química , DNA/genética , RNA/química , RNA/genética , Distrofia Miotônica/genética , Distrofia Miotônica/terapia , Células MuscularesRESUMO
Ribonuclease targeting chimeras (RiboTACs) induce degradation of an RNA target by facilitating an interaction between an RNA and a ribonuclease (RNase). We describe the screening of a DNA-encoded library (DEL) to identify binders of monomeric RNase L to provide a compound that induced dimerization of RNase L, activating its ribonuclease activity. This compound was incorporated into the design of a next-generation RiboTAC that targeted the microRNA-21 (miR-21) precursor and alleviated a miR-21-associated cellular phenotype in triple-negative breast cancer cells. The RNA-binding module in the RiboTAC is Dovitinib, a known receptor tyrosine kinase (RTK) inhibitor, which was previously identified to bind miR-21 as an off-target. Conversion of Dovitinib into this RiboTAC reprograms the known drug to selectively affect the RNA target. This work demonstrates that DEL can be used to identify compounds that bind and recruit proteins with effector functions in heterobifunctional compounds.
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MicroRNAs , Neoplasias de Mama Triplo Negativas , Humanos , Ribonucleases , DNARESUMO
The interactions between cellular RNAs in MDA-MB-231 triple negative breast cancer cells and a panel of small molecules appended with a diazirine cross-linking moiety and an alkyne tag were probed transcriptome-wide in live cells. The alkyne tag allows for facile pull-down of cellular RNAs bound by each small molecule, and the enrichment of each RNA target defines the compound's molecular footprint. Among the 34 chemically diverse small molecules studied, six bound and enriched cellular RNAs. The most highly enriched interaction occurs between the novel RNA-binding compound F1 and a structured region in the 5' untranslated region of quiescin sulfhydryl oxidase 1 isoform a (QSOX1-a), not present in isoform b. Additional studies show that F1 specifically bound RNA over DNA and protein; that is, we studied the entire DNA, RNA, and protein interactome. This interaction was used to design a ribonuclease targeting chimera (RIBOTAC) to locally recruit Ribonuclease L to degrade QSOX1 mRNA in an isoform-specific manner, as QSOX1-a, but not QSOX1-b, mRNA and protein levels were reduced. The RIBOTAC alleviated QSOX1-mediated phenotypes in cancer cells. This approach can be broadly applied to discover ligands that bind RNA in cells, which could be bioactive themselves or augmented with functionality such as targeted degradation.
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Oxirredutases atuantes sobre Doadores de Grupo Enxofre , RNA , Alcinos , Sítios de Ligação , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/metabolismo , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ribonucleases/metabolismo , TranscriptomaRESUMO
Myotonic dystrophy type 1 (DM1) is an incurable neuromuscular disorder caused by an expanded CTG repeat that is transcribed into r(CUG)exp The RNA repeat expansion sequesters regulatory proteins such as Muscleblind-like protein 1 (MBNL1), which causes pre-mRNA splicing defects. The disease-causing r(CUG)exp has been targeted by antisense oligonucleotides, CRISPR-based approaches, and RNA-targeting small molecules. Herein, we describe a designer small molecule, Cugamycin, that recognizes the structure of r(CUG)exp and cleaves it in both DM1 patient-derived myotubes and a DM1 mouse model, leaving short repeats of r(CUG) untouched. In contrast, oligonucleotides that recognize r(CUG) sequence rather than structure cleave both long and short r(CUG)-containing transcripts. Transcriptomic, histological, and phenotypic studies demonstrate that Cugamycin broadly and specifically relieves DM1-associated defects in vivo without detectable off-targets. Thus, small molecules that bind and cleave RNA have utility as lead chemical probes and medicines and can selectively target disease-causing RNA structures to broadly improve defects in preclinical animal models.
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Bleomicina/análogos & derivados , Distrofia Miotônica/genética , Distrofia Miotônica/metabolismo , Oligonucleotídeos/química , Splicing de RNA/genética , RNA/genética , RNA/metabolismo , Expansão das Repetições de Trinucleotídeos/genética , Animais , Bleomicina/química , Modelos Animais de Doenças , Desenho de Fármacos , Humanos , Camundongos , Oligonucleotídeos/metabolismoRESUMO
The NIH Virtual SARS-CoV-2 Antiviral Summit, held on 6 November 2020, was organized to provide an overview on the status and challenges in developing antiviral therapeutics for coronavirus disease 2019 (COVID-19), including combinations of antivirals. Scientific experts from the public and private sectors convened virtually during a live videocast to discuss severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) targets for drug discovery as well as the preclinical tools needed to develop and evaluate effective small-molecule antivirals. The goals of the Summit were to review the current state of the science, identify unmet research needs, share insights and lessons learned from treating other infectious diseases, identify opportunities for public-private partnerships, and assist the research community in designing and developing antiviral therapeutics. This report includes an overview of therapeutic approaches, individual panel summaries, and a summary of the discussions and perspectives on the challenges ahead for antiviral development.
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Antivirais/uso terapêutico , Tratamento Farmacológico da COVID-19 , SARS-CoV-2/efeitos dos fármacos , Antivirais/farmacologia , COVID-19/virologia , Desenvolvimento de Medicamentos , Humanos , National Institutes of Health (U.S.) , Peptídeo Hidrolases/metabolismo , Inibidores de Proteases/farmacologia , Inibidores de Proteases/uso terapêutico , Estados Unidos , Replicação Viral/efeitos dos fármacosRESUMO
Historically, translational inhibitors have been confined to anti-bacterials that globally affect translation. Lintner et al. demonstrate that small molecules can specifically inhibit translation of a single disease-associated protein by stalling the ribosome's nascent chain [1], opening up a new therapeutic strategy for 'undruggable' proteins.
Assuntos
Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Inibidores de PCSK9 , Biossíntese de Proteínas , Inibidores de Serina Proteinase/farmacologia , Compostos Heterocíclicos de 4 ou mais Anéis/química , Humanos , Pró-Proteína Convertase 9/biossíntese , Inibidores de Serina Proteinase/química , Relação Estrutura-AtividadeRESUMO
Reprogramming known medicines for a novel target with activity and selectivity over the canonical target is challenging. By studying the binding interactions between RNA folds and known small-molecule medicines and mining the resultant dataset across human RNAs, we identified that Dovitinib, a receptor tyrosine kinase (RTK) inhibitor, binds the precursor to microRNA-21 (pre-miR-21). Dovitinib was rationally reprogrammed for pre-miR-21 by using it as an RNA recognition element in a chimeric compound that also recruits RNase L to induce the RNA's catalytic degradation. By enhancing the inherent RNA-targeting activity and decreasing potency against canonical RTK protein targets in cells, the chimera shifted selectivity for pre-miR-21 by 2500-fold, alleviating disease progression in mouse models of triple-negative breast cancer and Alport Syndrome, both caused by miR-21 overexpression. Thus, targeted degradation can dramatically improve selectivity even across different biomolecules, i.e., protein versus RNA.