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1.
Sci Signal ; 13(651)2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32994211

RESUMO

There are currently no antiviral therapies specific for SARS-CoV-2, the virus responsible for the global pandemic disease COVID-19. To facilitate structure-based drug design, we conducted an x-ray crystallographic study of the SARS-CoV-2 nsp16-nsp10 2'-O-methyltransferase complex, which methylates Cap-0 viral mRNAs to improve viral protein translation and to avoid host immune detection. We determined the structures for nsp16-nsp10 heterodimers bound to the methyl donor S-adenosylmethionine (SAM), the reaction product S-adenosylhomocysteine (SAH), or the SAH analog sinefungin (SFG). We also solved structures for nsp16-nsp10 in complex with the methylated Cap-0 analog m7GpppA and either SAM or SAH. Comparative analyses between these structures and published structures for nsp16 from other betacoronaviruses revealed flexible loops in open and closed conformations at the m7GpppA-binding pocket. Bound sulfates in several of the structures suggested the location of the ribonucleic acid backbone phosphates in the ribonucleotide-binding groove. Additional nucleotide-binding sites were found on the face of the protein opposite the active site. These various sites and the conserved dimer interface could be exploited for the development of antiviral inhibitors.


Assuntos
Betacoronavirus/enzimologia , Infecções por Coronavirus/tratamento farmacológico , Metiltransferases/química , Pneumonia Viral/tratamento farmacológico , Proteínas não Estruturais Virais/química , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/farmacologia , Betacoronavirus/efeitos dos fármacos , Sítios de Ligação , Domínio Catalítico , Cristalografia por Raios X , Dimerização , Genes Virais/genética , Humanos , Metilação , Metiltransferases/antagonistas & inibidores , Modelos Moleculares , Fases de Leitura Aberta/genética , Pandemias , Ligação Proteica , Conformação Proteica , Análogos de Capuz de RNA/metabolismo , Processamento Pós-Transcricional do RNA , RNA Viral/metabolismo , S-Adenosil-Homocisteína/metabolismo , S-Adenosilmetionina/metabolismo , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas não Estruturais Virais/metabolismo
2.
3.
Nat Commun ; 11(1): 4153, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32814769

RESUMO

The histone methyltransferase DOT1L methylates lysine 79 (K79) on histone H3 and is involved in Mixed Lineage Leukemia (MLL) fusion leukemogenesis; however, its role in prostate cancer (PCa) is undefined. Here we show that DOT1L is overexpressed in PCa and is associated with poor outcome. Genetic and chemical inhibition of DOT1L selectively impaired the viability of androgen receptor (AR)-positive PCa cells and organoids, including castration-resistant and enzalutamide-resistant cells. The sensitivity of AR-positive cells is due to a distal K79 methylation-marked enhancer in the MYC gene bound by AR and DOT1L not present in AR-negative cells. DOT1L inhibition leads to reduced MYC expression and upregulation of MYC-regulated E3 ubiquitin ligases HECTD4 and MYCBP2, which promote AR and MYC degradation. This leads to further repression of MYC in a negative feed forward manner. Thus DOT1L selectively regulates the tumorigenicity of AR-positive prostate cancer cells and is a promising therapeutic target for PCa.


Assuntos
Histona-Lisina N-Metiltransferase/genética , Neoplasias da Próstata/genética , Proteínas Proto-Oncogênicas c-myc/genética , Receptores Androgênicos/genética , Adenosina/análogos & derivados , Adenosina/farmacologia , Animais , Linhagem Celular Tumoral , Intervalo Livre de Doença , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Masculino , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Compostos de Fenilureia/farmacologia , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/terapia , Estabilidade Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-myc/metabolismo , Interferência de RNA , Terapêutica com RNAi/métodos , Receptores Androgênicos/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
4.
Chem Biol Interact ; 330: 109228, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32827518

RESUMO

This study aimed at exploring the potential mechanism of decreased in vivo exposure of the antiplatelet agent, ticagrelor and its active metabolite, AR-C124910XX, mediated by tea polyphenols, which was first revealed by our previous study, as well as predicting the in vivo drug-drug interaction (DDI) potential utilizing an in vitro to in vivo extrapolation (IVIVE) approach. The bidirectional transport and uptake kinetics of ticagrelor were determined using Caco-2 cells. Inhibition potency of major components of tea polyphenols, epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were obtained from Caco-2 cells, human intestinal and hepatic microsomes (HIMs and HLMs) in vitro. A mean efflux ratio of 2.28 ± 0.38 and active uptake behavior of ticagrelor were observed in Caco-2 cell studies. Further investigation showed that the IC50 values of EGCG and EGC on the uptake of ticagrelor were 42.0 ± 5.1 µM (95% CI 31.9-54.8 µM) and 161 ± 13 µM (95% CI 136-191 µM), respectively. EGCG and EGC also displayed moderate to weak reversible inhibition on the formation of AR-C124910XX and the inactive metabolite, AR-C133913XX in HIMs and HLMs, while no clinically significant time-dependent inhibition was observed for either compound. IVIVE indicated a significant inhibition effect of EGCG on the uptake process of ticagrelor, while no potential DDI risk was found based on microsomal data. A 45% decrease in ticagrelor in vivo exposure was mechanistically predicted by incorporating intestinal and hepatic metabolism as well as intestinal absorption. This dual inhibition of tea polyphenols on ticagrelor revealed the underlying potential of transporter-enzyme interplay, in which the altered uptake process was more critical.


Assuntos
Modelos Teóricos , Polifenóis/farmacologia , Chá/química , Ticagrelor/antagonistas & inibidores , Adenosina/análogos & derivados , Adenosina/metabolismo , Transporte Biológico/efeitos dos fármacos , Células CACO-2 , Catequina/análogos & derivados , Catequina/farmacologia , Linhagem Celular Tumoral , Interações Medicamentosas , Humanos , Absorção Intestinal/efeitos dos fármacos , Cinética , Microssomos Hepáticos/metabolismo , Inibidores da Agregação de Plaquetas/farmacocinética , Antagonistas do Receptor Purinérgico P2Y/farmacocinética , Ticagrelor/metabolismo , Ticagrelor/farmacocinética
5.
Mol Cell ; 79(3): 361-362, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32763222

RESUMO

In this issue of Molecular Cell, Zhang et al. (2020) reveal that ATM triggers RNA methylation of DNA-RNA hybrids formed at double-strand breaks (DSBs) to modulate repair, adding a new layer of complexity to RNA's role in the DNA damage response.


Assuntos
Quebras de DNA de Cadeia Dupla , RNA , Adenosina/análogos & derivados , Proteínas Mutadas de Ataxia Telangiectasia , DNA , Reparo do DNA , Metilação
6.
PLoS One ; 15(8): e0236882, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790688

RESUMO

N6-methyladenosine (m6A) is the most prevalent type of RNA modification. METTL3 in the methyltransferase complex is the core enzyme responsible for methylation. METTL3 selectively catalyzes the adenosines centered in the RRAC motif. Functional studies established that m6A could enhance the translation efficiency (TE) of modified genes by recruiting reader protein YTHDF1 and other initiation factors. We downloaded the m6A peaks in HeLa cells from a previous study and defined the m6A modified genes and sites. Ancestral mutations in the genic region fixed in the HeLa cell samples were defined using their mRNA-Seq data and the alignment between human and mouse genomes. Furthermore, in the small interfering (si)-METTL3 sample, the calculated TE foldchange of all genes was compared to that in the negative control. The TE of m6A genes was globally down-regulated in si-METTL3 versus control compared to the non-m6A genes. In m6A modified genes, RRAC motif mutations were suppressed compared to mutations in non-motif regions or non-m6A genes. Among the m6A genes, a fraction RRAC motif mutations negatively correlated with the TE foldchange (si-METTL3 versus control). The TE of m6A modified genes was enhanced in HeLa cells. RRAC motif mutations could potentially prevent methylation of adenosines and consequently abolish the enhanced translation. Such mutations in the RRAC motif might be deleterious. Accordingly, we observed lower fractions of mutations in RRAC motifs than in other regions. This prevention of mutations in the RRAC motif could be a strategy adopted by cancer cells to maintain the elevated translation of particular genes.


Assuntos
Adenosina/análogos & derivados , Metiltransferases/genética , Adenosina/genética , Adenosina/metabolismo , Animais , Sequência de Bases , Células HeLa , Humanos , Metiltransferases/antagonistas & inibidores , Metiltransferases/metabolismo , Camundongos , Mutação , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo
7.
Environ Pollut ; 266(Pt 2): 115326, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32827984

RESUMO

Excessive exposure to cobalt (Co) is known to make adverse impact on the nervous system, but its detailed mechanisms of neurotoxicity have yet to be determined. In this study, C57BL/6 mice (0, 4, 8, 16 mg/kg CoCl2, 30 days) and human neuroblastoma H4 cells (0, 100, 400, 600 µM CoCl2) were used as in vivo and in vitro models. Our results revealed that CoCl2 intraperitoneal injection caused significant impairments in learning and memory, as well as pathological damage in the nervous system. We further certificated the alteration of m6A methylation induced by CoCl2 exposure. Our findings demonstrate for the first time, significant differences in the degree of m6A modification, the biological function of m6A-modified transcripts between cortex and H4 cell samples. Specifically, MeRIP-seq and RNA-seq elucidate that CoCl2 exposure results in differentially m6A-modified and expressed genes, which were enriched in pathways involving synaptic transmission, and central nervous system (CNS) development. Mechanistic analyses revealed that CoCl2 remarkably changed m6A modification level by affecting the expression of m6A methyltransferase and demethylase, and decreasing the activity of demethylase. We observed variation of m6A modification in neurodegenerative disease-associated genes upon CoCl2 exposure and identified regulatory strategy between m6A and potential targets mRNA. Our novel findings provide novel insight into the functional roles of m6A modification in neurodegenerative damage caused by environmental neurotoxicants and identify Co-mediated specific RNA regulatory strategy for broadening the epigenetic regulatory mechanism of RNA induced by heavy metals.


Assuntos
Cobalto , Neuroblastoma , Doenças Neurodegenerativas , RNA , Adenosina/análogos & derivados , Animais , Cobalto/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Aprendizagem , Memória , Camundongos , Camundongos Endogâmicos C57BL , RNA/efeitos dos fármacos
8.
DNA Cell Biol ; 39(10): 1767-1778, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32833542

RESUMO

N1-methyladenosine (m1A) is an important post-transcriptional modification in RNA, and plays critical roles in cellular functions. However, the relationship between m1A regulators and clinical significance of gynecological cancers remains unknown. In this study, we systematically analyzed RNA-seq and clinical data from several public database. Cell proliferation and migration assays were performed to verify the function of the m1A writer TRMT10C in cancer cells. We observed genetic alterations and dysregulated expressions of m1A regulators in gynecological cancer samples. We demonstrated that several m1A regulators could serve as prognostic biomarkers for gynecological cancer patients. The high correlations among the expression of m1A, N6-methyladenosine (m6A), and 5mC regulators were also revealed. Gene set enrichment analysis indicated that the mechanism of TRMT10C in regulating tumorigenesis was related to a variety of cancer-related pathways. Moreover, silencing TRMT10C suppressed the proliferation, colony formation, and migration of ovarian cancer and cervical cancer cells. In summary, our results highlight the importance of m1A regulators in regulating oncogenesis, and indicate that targeting specific m1A regulators might be a potential therapeutic strategy for gynecological cancers.


Assuntos
Biomarcadores Tumorais/genética , Metiltransferases/genética , Neoplasias Ovarianas/genética , Neoplasias do Colo do Útero/genética , Adenosina/análogos & derivados , Adenosina/metabolismo , Biomarcadores Tumorais/metabolismo , Movimento Celular , Proliferação de Células , Feminino , Células HeLa , Humanos , Metiltransferases/metabolismo , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/patologia
9.
Virology ; 548: 59-72, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32838947

RESUMO

Methylation of the N6 position of adenosine (m6A) is a widespread RNA modification that is critical for various physiological and pathological processes. Although this modification was also found in the RNA of several viruses almost 40 years ago, its biological functions during viral infection have been elucidated recently. Here, we investigated the effects of viral and host RNA methylation during porcine epidemic diarrhea virus (PEDV) infection. The results demonstrated that the m6A modification was abundant in the PEDV genome and the host methyltransferases METTL3 and METTL14 and demethylase FTO were involved in the regulation of viral replication. The knockdown of the methyltransferases increased PEDV replication while silencing the demethylase decreased PEDV output. Moreover, the proteins of the YTHDF family regulated the PEDV replication by affecting the stability of m6A-modified viral RNA. In particular, PEDV infection could trigger an increasement of m6A in host RNA and decrease the expression of FTO. The m6A modification sites in mRNAs and target genes were also altered during PEDV infection. Additionally, part of the host responses to PEDV infection was controlled by m6A modification, which could be reversed by the expression of FTO. Taken together, our results identified the role of m6A modification in PEDV replication and interactions with the host.


Assuntos
Adenosina/análogos & derivados , Infecções por Coronavirus/veterinária , Regulação da Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Vírus da Diarreia Epidêmica Suína/fisiologia , Doenças dos Suínos/genética , Doenças dos Suínos/virologia , Replicação Viral , Adenosina/metabolismo , Animais , Linhagem Celular , Chlorocebus aethiops , Genoma Viral , Metilação , Vírus da Diarreia Epidêmica Suína/ultraestrutura , Ligação Proteica , RNA Viral , Proteínas de Ligação a RNA/metabolismo , Suínos , Células Vero
10.
PLoS One ; 15(7): e0234103, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645016

RESUMO

Cyclin-dependent kinases (CDKs) contribute to the cancer hallmarks of uncontrolled proliferation and increased survival. As a result, over the last two decades substantial efforts have been directed towards identification and development of pharmaceutical CDK inhibitors. Insights into the biological consequences of CDK inhibition in specific tumor types have led to the successful development of CDK4/6 inhibitors as treatments for certain types of breast cancer. More recently, a new generation of pharmaceutical inhibitors of CDK enzymes that regulate the transcription of key oncogenic and pro-survival proteins, including CDK9, have entered clinical development. Here, we provide the first disclosure of the chemical structure of fadraciclib (CYC065), a CDK inhibitor and clinical candidate designed by further optimization from the aminopurine scaffold of seliciclib. We describe its synthesis and mechanistic characterization. Fadraciclib exhibits improved potency and selectivity for CDK2 and CDK9 compared to seliciclib, and also displays high selectivity across the kinome. We show that the mechanism of action of fadraciclib is consistent with potent inhibition of CDK9-mediated transcription, decreasing levels of RNA polymerase II C-terminal domain serine 2 phosphorylation, the pro-survival protein Myeloid Cell Leukemia 1 (MCL1) and MYC oncoprotein, and inducing rapid apoptosis in cancer cells. This cellular potency and mechanism of action translate to promising anti-cancer activity in human leukemia mouse xenograft models. Studies of leukemia cell line sensitivity identify mixed lineage leukemia (MLL) gene status and the level of B-cell lymphoma 2 (BCL2) family proteins as potential markers for selection of patients with greater sensitivity to fadraciclib. We show that the combination of fadraciclib with BCL2 inhibitors, including venetoclax, is synergistic in leukemic cell models, as predicted from simultaneous inhibition of MCL1 and BCL2 pro-survival pathways. Fadraciclib preclinical pharmacology data support its therapeutic potential in CDK9- or CDK2-dependent cancers and as a rational combination with BCL2 inhibitors in hematological malignancies. Fadraciclib is currently in Phase 1 clinical studies in patients with advanced solid tumors (NCT02552953) and also in combination with venetoclax in patients with relapsed or refractory chronic lymphocytic leukemia (CLL) (NCT03739554) and relapsed refractory acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) (NCT04017546).


Assuntos
Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/farmacologia , Animais , Antineoplásicos/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Quinase 2 Dependente de Ciclina/efeitos dos fármacos , Quinase 2 Dependente de Ciclina/metabolismo , Quinase 9 Dependente de Ciclina/efeitos dos fármacos , Quinase 9 Dependente de Ciclina/metabolismo , Quinases Ciclina-Dependentes/antagonistas & inibidores , Humanos , Camundongos , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Sulfonamidas/farmacologia
11.
Nat Commun ; 11(1): 3717, 2020 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-32709887

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the COVID-19 pandemic. 2'-O-RNA methyltransferase (MTase) is one of the enzymes of this virus that is a potential target for antiviral therapy as it is crucial for RNA cap formation; an essential process for viral RNA stability. This MTase function is associated with the nsp16 protein, which requires a cofactor, nsp10, for its proper activity. Here we show the crystal structure of the nsp10-nsp16 complex bound to the pan-MTase inhibitor sinefungin in the active site. Our structural comparisons reveal low conservation of the MTase catalytic site between Zika and SARS-CoV-2 viruses, but high conservation of the MTase active site between SARS-CoV-2 and SARS-CoV viruses; these data suggest that the preparation of MTase inhibitors targeting several coronaviruses - but not flaviviruses - should be feasible. Together, our data add to important information for structure-based drug discovery.


Assuntos
Betacoronavirus/enzimologia , Metiltransferases/química , Proteínas não Estruturais Virais/química , Proteínas Virais Reguladoras e Acessórias/química , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/farmacologia , Domínio Catalítico , Infecções por Coronavirus/virologia , Cristalografia por Raios X , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Humanos , Metiltransferases/metabolismo , Modelos Químicos , Modelos Moleculares , Pandemias , Pneumonia Viral/virologia , Capuzes de RNA , Estabilidade de RNA , RNA Viral/metabolismo , Proteínas não Estruturais Virais/metabolismo , Proteínas Virais Reguladoras e Acessórias/metabolismo
12.
Mol Cell ; 79(3): 425-442.e7, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32615088

RESUMO

Double-strand breaks (DSBs) are the most deleterious DNA lesions, which, if left unrepaired, may lead to genome instability or cell death. Here, we report that, in response to DSBs, the RNA methyltransferase METTL3 is activated by ATM-mediated phosphorylation at S43. Phosphorylated METTL3 is then localized to DNA damage sites, where it methylates the N6 position of adenosine (m6A) in DNA damage-associated RNAs, which recruits the m6A reader protein YTHDC1 for protection. In this way, the METTL3-m6A-YTHDC1 axis modulates accumulation of DNA-RNA hybrids at DSBs sites, which then recruit RAD51 and BRCA1 for homologous recombination (HR)-mediated repair. METTL3-deficient cells display defective HR, accumulation of unrepaired DSBs, and genome instability. Accordingly, depletion of METTL3 significantly enhances the sensitivity of cancer cells and murine xenografts to DNA damage-based therapy. These findings uncover the function of METTL3 and YTHDC1 in HR-mediated DSB repair, which may have implications for cancer therapy.


Assuntos
Adenosina/análogos & derivados , Neoplasias de Cabeça e Pescoço/genética , Metiltransferases/genética , Proteínas do Tecido Nervoso/genética , Fatores de Processamento de RNA/genética , Reparo de DNA por Recombinação/efeitos dos fármacos , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Adenosina/metabolismo , Animais , Antibióticos Antineoplásicos/farmacologia , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Bleomicina/farmacologia , Linhagem Celular Tumoral , DNA/genética , DNA/metabolismo , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Células HEK293 , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Metiltransferases/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteínas do Tecido Nervoso/metabolismo , Hibridização de Ácido Nucleico , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteoblastos/patologia , Fosforilação , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Fatores de Processamento de RNA/metabolismo , Rad51 Recombinase/genética , Rad51 Recombinase/metabolismo , Ribonuclease H/genética , Ribonuclease H/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/mortalidade , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Análise de Sobrevida , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Rev. esp. quimioter ; 33(3): 176-179, jun. 2020. ilus
Artigo em Espanhol | IBECS | ID: ibc-192929

RESUMO

El 31 de diciembre de 2019 se detectó en la ciudad de Wuhan (China) un brote neumonía causado por un nuevo coronavirus (SARS-CoV-2). Debido a la elevada capacidad de difusión e infección humana se ha convertido en una nueva pandemia zoónotica. La ausencia de una vacuna ha determinado la búsqueda de fármacos antivirales con capacidad para inhibir la replicación del nuevo virus. De entre ellos, remdesivir, un análogode la adenosina, es el que parece tener un futuro más prometedor. Este fármaco ha mostrado in vitro y en animales una elevada capacidad para bloquear la infección y replicación viralcon unas concentraciones alcanzables en el plasma humano.Aunque todos los estudios se han realizado con el SARS-CoV y el MERS-CoV, parece que por analogía virológica y funcional, remdesivir es de los pocos antivirales con demostrada eficacia. Sin embargo, se precisan estudios y ensayos clínicos en humanospara conocer el resultado de su aplicación en los mismos


On December 31, 2019 a pneumonia outbreak caused by a new coronavirus (SARS-CoV-2) was detected in the city of Wuhan (China). Due to the high capacity of diffusion and human infection it has become a new zoonotic pandemic. The absence of a vaccine has determined the search for antiviral drugs with the capacity to inhibit the replication of the new virus. Among them, remdesivir, an analogue of adenosine, is what seems to have a more promising future. This drug has shown in vitro and in animals a high capacity to block infection and viral replication with attainable concentrations in human plasma. Although all studies have been carried out with SARS-CoV and MERS-CoV, it seems that by virological and functional analogy, remdesivir is one of the few antiviral drugs with proven efficacy.However, studies and clinical trials in humans are required to know the result of their application in them


Assuntos
Humanos , Infecções por Coronavirus/tratamento farmacológico , Antivirais/administração & dosagem , Replicação Viral/efeitos dos fármacos , Trifosfato de Adenosina/farmacocinética , Resultado do Tratamento , Controle de Doenças Transmissíveis/métodos , Adenosina/análogos & derivados
14.
Buenos Aires; s.n; 12 jun. 2020.
Não convencional em Espanhol | LILACS, BRISA/RedTESA | ID: biblio-1116426

RESUMO

CONTEXTO CLÍNICO: La Enfermedad por el Coronavirus 2019 (COVID­19, por su sigla en inglés Coronavirus Disease 2019) es una enfermedad respiratoria de humanos producida por un nuevo coronavirus identificado con la sigla SARS-CoV-2.(1) El 11 de marzo de 2020 la Organización Mundial de la Salud (OMS) declaro la COVID-19 como una pandemia. Desde ese momento hasta este 01 de junio se han reportado más de 60.040.609 casos y la muerte de 370.657 personas. (2) El período de incubación de la infección es de 2 a 14 días. La mayor parte de los contagios se producen persona a persona, siendo altamente transmisible.(3) La clínica varía desde casos asintomáticos a cuadros febriles con tos y dificultad respiratoria, neumonía y distrés respiratorio. También puede acompañarse de alteraciones gastrointestinales. (3) En los casos con mal pronóstico, el paciente presenta un importante deterioro respiratorio en 4-8 días. Las imágenes radiológicas muestran generalmente neumonía focal o generalizada semejante al síndrome de distress respiratorio agudo. (3) La mayoría de los casos graves requieren ingreso hospitalario, siendo mayoritariamente casos primarios en pacientes de edad avanzada y con comorbilidades (diabetes, enfermedad crónica renal, hipertensión, enfermedad cardiaca y enfermedad pulmonar crónica). La tasa media de letalidad de los pacientes ingresados a UTI es cercana al 49%, siendo los valores más elevados en pacientes masculinos de más de 50 años con comorbilidades múltiples. (3) Actualmente el tratamiento de la COVID­19 es sintomático y de sostén no existiendo hasta el momento tratamiento farmacológico específico curativo. Recientemente se demostró que el remdesivir, un fármaco antiviral, ha demostrado inhibir la replicación viral del SARS-CoV-2 en células cultivadas, ratones y modelos de primates no humanos.(4) Se postula que el uso de remdesivir para el tratamiento de la COVID­19. TECNOLOGÍA: Remdesivir (GS-5734) es un profármaco análogo de la adenosina que compite preferentemente por el ATP viral y se incorpora como falso nucleósido a la nueva cadena del ARN viral.(1) Al incorporarse a las cadenas de ARN virales durante su replicación da como resultado la terminación prematura de la misma. La dosis de inicio recomendada es de 200 mg administrada de manera endovenosa el primer día, seguido de 100mg una vez al día durante 9 días. OBJETIVO: El objetivo del presente informe es evaluar la evidencia disponible acerca de la eficacia, seguridad y aspectos relacionados a las políticas de cobertura del uso de remdesivir para el tratamiento de la COVID­19. MÉTODOS: Se realizó una búsqueda en las principales bases de datos bibliográficas, en buscadores genéricos de internet, y financiadores de salud. Se priorizó la inclusión de revisiones sistemáticas (RS), ensayos clínicos controlados aleatorizados (ECAs), evaluaciones de tecnologías sanitarias (ETS), evaluaciones económicas, guías de práctica clínica (GPC) y políticas de cobertura de diferentes sistemas de salud. RESULTADOS: Se incluyeron una revisión sistemática con meta-análisis, tres ECAs, un estudio observacional, y nueve GPC sobre el tratamiento de pacientes con diagnóstico de COVID­19. CONCLUSIONES: Evidencia de baja calidad sugiere que el uso de remdesivir podría disminuir la mortalidad en pacientes con COVID-19, aunque la imprecisión de los resultados no permite formular conclusiones definitivas. Evidencia de moderada calidad sugiere que reduciría el tiempo a la mejoría clínica. Evidencia de moderada calidad no encontró diferencias entre una pauta de administración durante 10 versus 5 días al evaluar mortalidad y tasa de recuperación. El Instituto Nacional de los Estados Unidos y la Agencia Española de Medicamentos y Productos Sanitarios sugieren su utilización en pacientes con COVID-19 severa. El resto de las guías de práctica clínica, recomendaciones de las principales sociedades internacionales, organismos gubernamentales o consensos de expertos consultadas no recomiendan su utilización fuera de estudios de investigación a la espera de los resultados finales de múltiples ensayos clínicos aleatorizados que se encuentran en curso. No se encontraron estudios de costo-efectividad o de impacto presupuestario en Latinoamérica.


Assuntos
Pneumonia Viral/tratamento farmacológico , Adenosina/análogos & derivados , Infecções por Coronavirus/tratamento farmacológico , Avaliação da Tecnologia Biomédica , Avaliação em Saúde , Análise Custo-Benefício
15.
Nature ; 582(7810): 60-66, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32494078

RESUMO

The nature of the first genetic polymer is the subject of major debate1. Although the 'RNA world' theory suggests that RNA was the first replicable information carrier of the prebiotic era-that is, prior to the dawn of life2,3-other evidence implies that life may have started with a heterogeneous nucleic acid genetic system that included both RNA and DNA4. Such a theory streamlines the eventual 'genetic takeover' of homogeneous DNA from RNA as the principal information-storage molecule, but requires a selective abiotic synthesis of both RNA and DNA building blocks in the same local primordial geochemical scenario. Here we demonstrate a high-yielding, completely stereo-, regio- and furanosyl-selective prebiotic synthesis of the purine deoxyribonucleosides: deoxyadenosine and deoxyinosine. Our synthesis uses key intermediates in the prebiotic synthesis of the canonical pyrimidine ribonucleosides (cytidine and uridine), and we show that, once generated, the pyrimidines persist throughout the synthesis of the purine deoxyribonucleosides, leading to a mixture of deoxyadenosine, deoxyinosine, cytidine and uridine. These results support the notion that purine deoxyribonucleosides and pyrimidine ribonucleosides may have coexisted before the emergence of life5.


Assuntos
DNA/química , Evolução Química , Origem da Vida , Nucleosídeos de Purina/síntese química , Nucleosídeos de Pirimidina/síntese química , RNA/química , Adenosina/análogos & derivados , Adenosina/química , Citidina/química , DNA/genética , Oxirredução/efeitos da radiação , Nucleosídeos de Purina/química , Nucleosídeos de Purina/genética , Nucleosídeos de Pirimidina/química , Nucleosídeos de Pirimidina/genética , RNA/genética , Uridina/química
16.
Buenos Aires; IECS; 8 maio 2020.
Não convencional em Espanhol | LILACS, BRISA/RedTESA | ID: biblio-1099569

RESUMO

CONTEXTO CLÍNICO: La Enfermedad por el Coronavirus 2019 (COVID­19, por su sigla en inglés Coronavirus Disease 2019) es una enfermedad respiratoria de humanos producida por un nuevo coronavirus identificado con la sigla SARS-CoV-2. El 11 de marzo de 2020 la Organización Mundial de la Salud (OMS) declaro la COVID-19 como una pandemia. Desde ese momento hasta este 01 de abril su circulación se ha reportado en 205 países reportándose más de 800.000 casos y la muerte 40.000 personas. TECNOLOGÍA: Remdesivir (GS-5734) es un profármaco análogo de la adenosina que compite preferentemente por el ATP viral y se incorpora como falso nucleósido a la nueva cadena del ARN viral. Al incorporarse a las cadenas de ARN virales durante su replicación da como resultado la terminación prematura de la misma. La dosis de inicio recomendada es de 200 mg administrada de manera endovenosa el primer día, seguido de 100mg una vez al día durante 9 días. OBJETIVO: El objetivo del presente informe es evaluar la evidencia disponible acerca de la eficacia, seguridad y aspectos relacionados a las políticas de cobertura del uso de remdesivir para el tratamiento de la COVID­19. MÉTODOS: Se realizó una búsqueda en las principales bases de datos bibliográficas, en buscadores genéricos de internet, y financiadores de salud. Se priorizó la inclusión de revisiones sistemáticas (RS), ensayos clínicos controlados aleatorizados (ECAs), evaluaciones de tecnologías sanitarias (ETS), evaluaciones económicas, guías de práctica clínica (GPC) y políticas de cobertura de diferentes sistemas de salud. RESULTADOS: Se incluyeron un ECA, un estudio observacional, y nueve GPC sobre el tratamiento de pacientes con diagnóstico de COVID­19. CONCLUSIONES: Evidencia de baja calidad proveniente de un ensayo clínico aleatorizado, detenido prematuramente sugiere que el uso de remdesivir no estaría asociado a una disminución de la mortalidad, o del tiempo a la mejoría clínica en pacientes con COVID-19. Múltiples ensayos clínicos aleatorizados en pacientes con cuadros moderados o severos se encuentran en curso. Actualmente las principales guías de práctica clínica y recomendaciones de las principales sociedades internacionales, organismos gubernamentales o consensos de expertos no lo mencionan ni lo recomiendan para el tratamiento de estos pacientes, siendo su uso restringido a estudios de investigación. No se encontraron estudios de costo-efectividad o de impacto presupuestario en Latinoamérica.


Assuntos
Adenosina/análogos & derivados , Infecções por Coronavirus/tratamento farmacológico , Betacoronavirus/efeitos dos fármacos , Avaliação da Tecnologia Biomédica , Análise Custo-Eficiência
17.
Nucleic Acids Res ; 48(10): 5684-5694, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32356894

RESUMO

Studies on biological functions of N6-methyladenosine (m6A) modification in mRNA have drawn significant attention in recent years. Here we describe the construction and characterization of a CRISPR-Cas13b-based tool for targeted demethylation of specific mRNA. A fusion protein, named dm6ACRISPR, was created by linking a catalytically inactive Type VI-B Cas13 enzyme from Prevotella sp. P5-125 (dPspCas13b) to m6A demethylase AlkB homolog 5 (ALKBH5). dm6ACRISPR specifically demethylates m6A of targeted mRNA such as cytochrome b5 form A (CYB5A) to increase its mRNA stability. It can also demethylate ß-catenin-encoding CTNNB1 mRNA that contains multiple m6A sites to trigger its translation. In addition, the dm6ACRISPR system incurs efficient demethylation of targeted epitranscriptome transcripts with limited off-target effects. Targeted demethylation of transcripts coding for oncoproteins such as epidermal growth factor receptor (EGFR) and MYC can suppress proliferation of cancer cells. Together, we provide a programmable and in vivo manipulation tool to study mRNA modification of specific genes and their related biological functions.


Assuntos
Homólogo AlkB 5 da RNA Desmetilase/metabolismo , Proteínas Associadas a CRISPR/genética , Sistemas CRISPR-Cas , RNA Mensageiro/metabolismo , Regiões 5' não Traduzidas , Adenosina/análogos & derivados , Adenosina/metabolismo , Homólogo AlkB 5 da RNA Desmetilase/genética , Proliferação de Células , Desmetilação , Células HEK293 , Células HeLa , Humanos , Oncogenes , Prevotella/enzimologia , Engenharia de Proteínas , RNA Mensageiro/química , Proteínas Recombinantes de Fusão/metabolismo
18.
Nucleic Acids Res ; 48(11): 6251-6264, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32406913

RESUMO

m6A is a prevalent internal modification in mRNAs and has been linked to the diverse effects on mRNA fate. To explore the landscape and evolution of human m6A, we generated 27 m6A methylomes across major adult tissues. These data reveal dynamic m6A methylation across tissue types, uncover both broadly or tissue-specifically methylated sites, and identify an unexpected enrichment of m6A methylation at non-canonical cleavage sites. A comparison of fetal and adult m6A methylomes reveals that m6A preferentially occupies CDS regions in fetal tissues. Moreover, the m6A sub-motifs vary between fetal and adult tissues or across tissue types. From the evolutionary perspective, we uncover that the selection pressure on m6A sites varies and depends on their genic locations. Unexpectedly, we found that ∼40% of the 3'UTR m6A sites are under negative selection, which is higher than the evolutionary constraint on miRNA binding sites, and much higher than that on A-to-I RNA modification. Moreover, the recently gained m6A sites in human populations are clearly under positive selection and associated with traits or diseases. Our work provides a resource of human m6A profile for future studies of m6A functions, and suggests a role of m6A modification in human evolutionary adaptation and disease susceptibility.


Assuntos
Adenosina/análogos & derivados , Metilação de DNA , Evolução Molecular , Regiões 3' não Traduzidas , Adenosina/metabolismo , Adulto , Suscetibilidade a Doenças , Epigenoma , Feto/metabolismo , Genética Populacional , Células HEK293 , Humanos , Metiltransferases/deficiência , Metiltransferases/genética , Especificidade de Órgãos
20.
Nat Commun ; 11(1): 2578, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32444598

RESUMO

Studies on biological functions of N6-methyladenosine (m6A) modification in mRNA have sprung up in recent years. We find m6A can positively regulate the glycolysis of cancer cells. Specifically, m6A-sequencing and functional studies confirm that pyruvate dehydrogenase kinase 4 (PDK4) is involved in m6A regulated glycolysis and ATP generation. The m6A modified 5'UTR of PDK4 positively regulates its translation elongation and mRNA stability via binding with YTHDF1/eEF-2 complex and IGF2BP3, respectively. Targeted specific demethylation of PDK4 m6A by dm6ACRISPR system can significantly decrease the expression of PDK4 and glycolysis of cancer cells. Further, TATA-binding protein (TBP) can transcriptionally increase the expression of Mettl3 in cervical cancer cells via binding to its promoter. In vivo and clinical data confirm the positive roles of m6A/PDK4 in tumor growth and progression of cervical and liver cancer. Our study reveals that m6A regulates glycolysis of cancer cells through PDK4.


Assuntos
Adenosina/análogos & derivados , Glicólise/fisiologia , Quinase Piruvato Desidrogenase (Transferência de Acetil)/metabolismo , Neoplasias do Colo do Útero/genética , Regiões 5' não Traduzidas , Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Feminino , Glicólise/genética , Células HeLa , Humanos , Estimativa de Kaplan-Meier , Metiltransferases/genética , Metiltransferases/metabolismo , Camundongos Endogâmicos BALB C , Regiões Promotoras Genéticas , Quinase Piruvato Desidrogenase (Transferência de Acetil)/genética , Estabilidade de RNA , Proteínas de Ligação a RNA/metabolismo , Neoplasias do Colo do Útero/mortalidade , Ensaios Antitumorais Modelo de Xenoenxerto
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