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1.
Buenos Aires; IECS; 20 nov. 2020.
No convencional en Español | LILACS, BRISA/RedTESA | ID: biblio-1140947

RESUMEN

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 uma pandemia.2 Desde ese momento Desde ese momento hasta el 10 de Noviembre, su circulación se há reportado en más de 200 países reportándose más de 14.300.000 casos activos a la fecha y más de 37.834.00 casos cerrados de los cuales el 3% de estos murió (1.284.690 casos). 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. La clínica varía desde casos asintomáticos a cuadros febriles con tos y dificultad respiratoria, neumonía y distrés respiratorio. También puede acompañarse de alteraciones gastrointestinales. 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. La mayoría de los casos graves requieren ingresso hospitalario, siendo mayoritariamente casos primarios en pacientes de edad avanzada y com 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 com comorbilidades múltiples. Actualmente el tratamiento de la COVID­19 es sintomático y de sostén no existiendo hasta el momento tratamiento farmacológico específico curativo. Debido a que mediante estudios in vitro se demostró que el remdesivir, un fármaco antiviral, inhibe la replicación viral del SARS-CoV-2 en células cultivadas, ratones y modelos de primates no humanos, se postuló el uso de remdesivir para el tratamiento de la infección por 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. 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 dos revisiones sistemáticas, una con meta-análisis, cuatro ECAs, un estúdio observacional, y ocho recomendaciones sobre el tratamiento con remdesivir en pacientes com diagnóstico de COVID­19. CONCLUSIONES: Evidencia de baja calidad sugiere que el uso de remdesivir podría disminuirla 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 baja calidad sugiere que la administración de 5 días versus 10 días podría generar mejorías en la mortalidad y tasa de recuperación. El Instituto Nacional de los Estados Unidos y la Sociedad Estadounidense de Enfermedades Infecciosas sugieren su utilización en pacientes con COVID-19 internados con requerimiento de oxígeno suplementario. Guías de práctica clínica y sociedades internacionales, organismos gubernamentales o consensos de expertos como el Instituto Nacional de Salud y Cuidados de Excelencia del Reino Unido, el Grupo Colaborativo Internacional para el tratamiento de la sepsis y el shock septicémico, entre otras; no recomiendan su utilización fuera de estudios de investigación a la espera de los resultados finales de múltiples ensayos clínicos aleatorizados que se encuentran em curso. La Organización Mundial de la Salud no recomienda su uso en base a la falta de evidencia em cuanto a sus beneficios. No se encontraron estudios de costo-efectividad o de impacto presupuestario en Latinoamérica.


Asunto(s)
Humanos , Neumonía Viral/tratamiento farmacológico , Adenosina/análogos & derivados , Infecciones por Coronavirus/tratamiento farmacológico , Betacoronavirus/efectos de los fármacos , Evaluación de la Tecnología Biomédica
2.
Viruses ; 12(11)2020 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-33121021

RESUMEN

This is the first report of a successful treatment of a non-effusive feline infectious peritonitis (FIP) uveitis case using an oral adenosine nucleoside analogue drug and feline interferon omega, and alpha-1 acid glycoprotein (AGP) as an indicator of recovery. A 2-year-old male neutered Norwegian Forest Cat presented with uveitis, keratic precipitates, mesenteric lymphadenopathy and weight loss. The cat was hypergammaglobulinaemic and had a non-regenerative anaemia. Feline coronavirus (FCoV) RNA was detected in a mesenteric lymph node fine-needle aspirate by a reverse-transcriptase polymerase chain reaction-non-effusive FIP was diagnosed. Prednisolone acetate eye drops were administered three times daily for 2 weeks. Oral adenosine nucleoside analogue (Mutian) treatment started. Within 50 days of Mutian treatment, the cat had gained over one kilogram in weight, his globulin level reduced from 77 to 51 g/L and his haematocrit increased from 22 to 35%; his uveitis resolved and his sight improved. Serum AGP level reduced from 3100 to 400 µg/mL (within normal limits). Symmetric dimethylarginine (SDMA) was above normal at 28 µg/dL, reducing to 14 µg/dL on the cessation of treatment; whether the SDMA increase was due to FIP lesions in the kidney or Mutian is unknown. Mutian treatment stopped and low-dose oral recombinant feline interferon omega begun-the cat's recovery continued.


Asunto(s)
Adenosina/uso terapéutico , Peritonitis Infecciosa Felina/tratamiento farmacológico , Interferón Tipo I/uso terapéutico , Nucleósidos/uso terapéutico , Uveítis/tratamiento farmacológico , Uveítis/veterinaria , Adenosina/análogos & derivados , Animales , Antivirales/uso terapéutico , Arginina/análogos & derivados , Arginina/sangre , Gatos , Coronavirus Felino/efectos de los fármacos , Coronavirus Felino/aislamiento & purificación , Peritonitis Infecciosa Felina/diagnóstico , Peritonitis Infecciosa Felina/virología , Glicoproteínas/metabolismo , Masculino , Uveítis/diagnóstico
3.
Cell Prolif ; 53(11): e12921, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33029866

RESUMEN

N6 -methyladenosine (m6 A) RNA modification, first discovered in 1974, is the most prevalent, abundant and penetrating messenger RNA (mRNA) modification in eukaryotes. This governs the fate of modified transcripts, regulates RNA metabolism and biological processes, and participates in pathogenesis of numerous human diseases, especially in cancer through the reciprocal regulation of m6 A methyltransferases ("writers") and demethylases ("erasers") and the binding proteins decoding m6 A methylation ("readers"). Accumulating evidence indicates a complicated regulation network of m6 A modification involving multiple m6 A-associated regulatory proteins whose biological functions have been further analysed. This review aimed to summarize the current knowledge on the potential significance and molecular mechanisms of m6 A RNA modification in the initiation and progression of cancer.


Asunto(s)
Adenosina/análogos & derivados , Neoplasias/metabolismo , ARN Mensajero/metabolismo , Adenosina/metabolismo , Animales , Progresión de la Enfermedad , Humanos , Metilación , Metiltransferasas/metabolismo , Neoplasias/patología
4.
Nucleic Acids Res ; 48(19): 11083-11096, 2020 11 04.
Artículo en Inglés | MEDLINE | ID: mdl-33035345

RESUMEN

N6-Methyladenosine (m6A) messenger RNA methylation is a well-known epitranscriptional regulatory mechanism affecting central biological processes, but its function in human cellular senescence remains uninvestigated. Here, we found that levels of both m6A RNA methylation and the methyltransferase METTL3 were reduced in prematurely senescent human mesenchymal stem cell (hMSC) models of progeroid syndromes. Transcriptional profiling of m6A modifications further identified MIS12, for which m6A modifications were reduced in both prematurely senescent hMSCs and METTL3-deficient hMSCs. Knockout of METTL3 accelerated hMSC senescence whereas overexpression of METTL3 rescued the senescent phenotypes. Mechanistically, loss of m6A modifications accelerated the turnover and decreased the expression of MIS12 mRNA while knockout of MIS12 accelerated cellular senescence. Furthermore, m6A reader IGF2BP2 was identified as a key player in recognizing and stabilizing m6A-modified MIS12 mRNA. Taken together, we discovered that METTL3 alleviates hMSC senescence through m6A modification-dependent stabilization of the MIS12 transcript, representing a novel epitranscriptional mechanism in premature stem cell senescence.


Asunto(s)
Adenosina/análogos & derivados , Metiltransferasas/metabolismo , Proteínas Asociadas a Microtúbulos/genética , Progeria/genética , ARN Mensajero/metabolismo , Síndrome de Werner/genética , Adenosina/genética , Células Cultivadas , Senescencia Celular , Humanos , Células Madre Mesenquimatosas , Metilación , Proteínas de Unión al ARN/metabolismo
7.
Sci Signal ; 13(651)2020 09 29.
Artículo en Inglés | MEDLINE | ID: mdl-32994211

RESUMEN

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.


Asunto(s)
Betacoronavirus/enzimología , Infecciones por Coronavirus/tratamiento farmacológico , Metiltransferasas/química , Neumonía Viral/tratamiento farmacológico , Proteínas no Estructurales Virales/química , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/farmacología , Betacoronavirus/efectos de los fármacos , Sitios de Unión , Dominio Catalítico , Cristalografía por Rayos X , Dimerización , Genes Virales/genética , Humanos , Metilación , Metiltransferasas/antagonistas & inhibidores , Modelos Moleculares , Sistemas de Lectura Abierta/genética , Pandemias , Unión Proteica , Conformación Proteica , Análogos de Caperuza de ARN/metabolismo , Procesamiento Postranscripcional del ARN , ARN Viral/metabolismo , S-Adenosilhomocisteína/metabolismo , S-Adenosilmetionina/metabolismo , Relación Estructura-Actividad , Proteínas no Estructurales Virales/antagonistas & inhibidores , Proteínas no Estructurales Virales/metabolismo
8.
Plant Physiol ; 183(4): 1416-1417, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32747489
9.
DNA Cell Biol ; 39(10): 1767-1778, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32833542

RESUMEN

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.


Asunto(s)
Biomarcadores de Tumor/genética , Metiltransferasas/genética , Neoplasias Ováricas/genética , Neoplasias del Cuello Uterino/genética , Adenosina/análogos & derivados , Adenosina/metabolismo , Biomarcadores de Tumor/metabolismo , Movimiento Celular , Proliferación Celular , Femenino , Células HeLa , Humanos , Metiltransferasas/metabolismo , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/patología , Neoplasias del Cuello Uterino/metabolismo , Neoplasias del Cuello Uterino/patología
10.
Virology ; 548: 59-72, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32838947

RESUMEN

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.


Asunto(s)
Adenosina/análogos & derivados , Infecciones por Coronavirus/veterinaria , Regulación de la Expresión Génica , Interacciones Huésped-Patógeno/genética , Virus de la Diarrea Epidémica Porcina/fisiología , Enfermedades de los Porcinos/genética , Enfermedades de los Porcinos/virología , Replicación Viral , Adenosina/metabolismo , Animales , Línea Celular , Chlorocebus aethiops , Genoma Viral , Metilación , Virus de la Diarrea Epidémica Porcina/ultraestructura , Unión Proteica , ARN Viral , Proteínas de Unión al ARN/metabolismo , Porcinos , Células Vero
11.
Chem Biol Interact ; 330: 109228, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-32827518

RESUMEN

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.


Asunto(s)
Modelos Teóricos , Polifenoles/farmacología , Té/química , Ticagrelor/antagonistas & inhibidores , Adenosina/análogos & derivados , Adenosina/metabolismo , Transporte Biológico/efectos de los fármacos , Células CACO-2 , Catequina/análogos & derivados , Catequina/farmacología , Línea Celular Tumoral , Interacciones Farmacológicas , Humanos , Absorción Intestinal/efectos de los fármacos , Cinética , Microsomas Hepáticos/metabolismo , Inhibidores de Agregación Plaquetaria/farmacocinética , Antagonistas del Receptor Purinérgico P2Y/farmacocinética , Ticagrelor/metabolismo , Ticagrelor/farmacocinética
12.
Environ Pollut ; 266(Pt 2): 115326, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32827984

RESUMEN

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.


Asunto(s)
Cobalto , Neuroblastoma , Enfermedades Neurodegenerativas , ARN , Adenosina/análogos & derivados , Animales , Cobalto/toxicidad , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Aprendizaje , Memoria , Ratones , Ratones Endogámicos C57BL , ARN/efectos de los fármacos
13.
Nucleic Acids Res ; 48(16): 9250-9261, 2020 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-32813009

RESUMEN

N 6-methylation of 2'-O-methyladenosine (Am) in RNA occurs in eukaryotic cells to generate N6,2'-O-dimethyladenosine (m6Am). Identification of the methyltransferase responsible for m6Am catalysis has accelerated studies on the function of m6Am in RNA processing. While m6Am is generally found in the first transcribed nucleotide of mRNAs, the modification is also found internally within U2 snRNA. However, the writer required for catalyzing internal m6Am formation had remained elusive. By sequencing transcriptome-wide RNA methylation at single-base-resolution, we identified human METTL4 as the writer that directly methylates Am at U2 snRNA position 30 into m6Am. We found that METTL4 localizes to the nucleus and its conserved methyltransferase catalytic site is required for U2 snRNA methylation. By sequencing human cells with overexpressed Mettl4, we determined METTL4's in vivo target RNA motif specificity. In the absence of Mettl4 in human cells, U2 snRNA lacks m6Am thereby affecting a subset of splicing events that exhibit specific features such as 3' splice-site weakness and an increase in exon inclusion. These findings suggest that METTL4 methylation of U2 snRNA regulates splicing of specific pre-mRNA transcripts.


Asunto(s)
Adenosina/análogos & derivados , Metiltransferasas/genética , Empalme del ARN/genética , ARN Nuclear Pequeño/genética , Adenosina/genética , Catálisis , Exones/genética , Humanos , Metilación , Precursores del ARN/genética , Sitios de Empalme de ARN/genética , ARN Mensajero/genética , Empalmosomas/genética
14.
Nat Genet ; 52(9): 870-877, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32778823

RESUMEN

A dynamic epigenome is critical for appropriate gene expression in development and health1-5. Central to this is the intricate process of transcription6-11, which integrates cellular signaling with chromatin changes, transcriptional machinery and modifications to messenger RNA, such as N6-methyladenosine (m6A), which is co-transcriptionally incorporated. The integration of these aspects of the dynamic epigenome, however, is not well understood mechanistically. Here we show that the repressive histone mark H3K9me2 is specifically removed by the induction of m6A-modified transcripts. We demonstrate that the methyltransferase METTL3/METTL14 regulates H3K9me2 modification. We observe a genome-wide correlation between m6A and occupancy by the H3K9me2 demethylase KDM3B, and we find that the m6A reader YTHDC1 physically interacts with and recruits KDM3B to m6A-associated chromatin regions, promoting H3K9me2 demethylation and gene expression. This study establishes a direct link between m6A and dynamic chromatin modification and provides mechanistic insight into the co-transcriptional interplay between RNA modifications and histone modifications.


Asunto(s)
Adenosina/análogos & derivados , Histonas/genética , Adenosina/genética , Línea Celular , Cromatina/genética , Expresión Génica/genética , Células HEK293 , Humanos , Metilación , Metiltransferasas/genética , ARN Mensajero/genética , Transcripción Genética/genética
15.
Mol Cell ; 79(3): 361-362, 2020 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-32763222

RESUMEN

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.


Asunto(s)
Roturas del ADN de Doble Cadena , ARN , Adenosina/análogos & derivados , Proteínas de la Ataxia Telangiectasia Mutada , ADN , Reparación del ADN , Metilación
16.
PLoS One ; 15(8): e0236882, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32790688

RESUMEN

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.


Asunto(s)
Adenosina/análogos & derivados , Metiltransferasas/genética , Adenosina/genética , Adenosina/metabolismo , Animales , Secuencia de Bases , Células HeLa , Humanos , Metiltransferasas/antagonistas & inhibidores , Metiltransferasas/metabolismo , Ratones , Mutación , Interferencia de ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Interferente Pequeño/metabolismo
17.
Nat Commun ; 11(1): 4153, 2020 08 19.
Artículo en Inglés | MEDLINE | ID: mdl-32814769

RESUMEN

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.


Asunto(s)
N-Metiltransferasa de Histona-Lisina/genética , Neoplasias de la Próstata/genética , Proteínas Proto-Oncogénicas c-myc/genética , Receptores Androgénicos/genética , Adenosina/análogos & derivados , Adenosina/farmacología , Animales , Línea Celular Tumoral , Supervivencia sin Enfermedad , Perfilación de la Expresión Génica/métodos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , N-Metiltransferasa de Histona-Lisina/antagonistas & inhibidores , N-Metiltransferasa de Histona-Lisina/metabolismo , Humanos , Masculino , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Compuestos de Fenilurea/farmacología , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/terapia , Estabilidad Proteica/efectos de los fármacos , Proteínas Proto-Oncogénicas c-myc/metabolismo , Interferencia de ARN , Tratamiento con ARN de Interferencia/métodos , Receptores Androgénicos/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto/métodos
18.
Chemosphere ; 261: 127757, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32726721

RESUMEN

N6-methyladenosine (m6A) is one of the most common RNA modifications in eukaryotes involved in the regulation of post-transcriptional gene expression, as well as the occurrence and development of diseases related to environmental exposures. Adverse factors produced by environmental exposures, such as reactive oxygen species, inflammation, and cyclobutane pyrimidine dimers, mediate m6A modification, thereby regulating downstream gene and protein expression, and signaling pathways, such as FTO/m6A RNA/p53 axis, PI3K/AKT/mTOR pathway, and PARP/METTL3/m6A RNA/Pol κ pathway. Moreover, an imbalance in m6A methylation levels directly mediates disease pathogenesis. To date, some studies have detailed the mechanisms underlying environmental exposure-mediated global changes in RNA m6A methylation. Based on our current understanding, we aimed to elaborate on the molecular mechanisms through which RNA m6A methylation regulates gene expression under environmental exposures. In this review, we outline the biogenesis and functions of RNA m6A modification. Furthermore, we focus on the effects of environmental exposures on m6A levels and highlight the relationships between environmental exposures (doses and time) and m6A levels. Although the molecular mechanisms regulating gene expression remains to be elucidated, m6A has potential applications as a disease biomarker.


Asunto(s)
Adenosina/análogos & derivados , Exposición a Riesgos Ambientales , Contaminación Ambiental/efectos adversos , Regulación de la Expresión Génica , Procesamiento Postranscripcional del ARN/genética , ARN/genética , Adenosina/genética , Células Eucariotas/efectos de los fármacos , Humanos , Metilación , Transducción de Señal/genética
19.
Mol Cell ; 79(3): 425-442.e7, 2020 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-32615088

RESUMEN

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.


Asunto(s)
Adenosina/análogos & derivados , Neoplasias de Cabeza y Cuello/genética , Metiltransferasas/genética , Proteínas del Tejido Nervioso/genética , Factores de Empalme de ARN/genética , Reparación del ADN por Recombinación/efectos de los fármacos , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Adenosina/metabolismo , Animales , Antibióticos Antineoplásicos/farmacología , Proteínas de la Ataxia Telangiectasia Mutada/genética , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Bleomicina/farmacología , Línea Celular Tumoral , ADN/genética , ADN/metabolismo , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Células Epiteliales/patología , Femenino , Células HEK293 , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/mortalidad , Neoplasias de Cabeza y Cuello/patología , Humanos , Metiltransferasas/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Proteínas del Tejido Nervioso/metabolismo , Hibridación de Ácido Nucleico , Osteoblastos/efectos de los fármacos , Osteoblastos/metabolismo , Osteoblastos/patología , Fosforilación , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Factores de Empalme de ARN/metabolismo , Recombinasa Rad51/genética , Recombinasa Rad51/metabolismo , Ribonucleasa H/genética , Ribonucleasa H/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico , Carcinoma de Células Escamosas de Cabeza y Cuello/mortalidad , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Análisis de Supervivencia , Ensayos Antitumor por Modelo de Xenoinjerto
20.
Nat Genet ; 52(9): 939-949, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32601472

RESUMEN

N6-methyladenosine (m6A) plays important roles in regulating messenger RNA processing. Despite rapid progress in this field, little is known about the genetic determinants of m6A modification and their role in common diseases. In this study, we mapped the quantitative trait loci (QTLs) of m6A peaks in 60 Yoruba (YRI) lymphoblastoid cell lines. We found that m6A QTLs are largely independent of expression and splicing QTLs and are enriched with binding sites of RNA-binding proteins, RNA structure-changing variants and transcriptional features. Joint analysis of the QTLs of m6A and related molecular traits suggests that the downstream effects of m6A are heterogeneous and context dependent. We identified proteins that mediate m6A effects on translation. Through integration with data from genome-wide association studies, we show that m6A QTLs contribute to the heritability of various immune and blood-related traits at levels comparable to splicing QTLs and roughly half of expression QTLs. By leveraging m6A QTLs in a transcriptome-wide association study framework, we identified putative risk genes of these traits.


Asunto(s)
Adenosina/análogos & derivados , ARN Mensajero/genética , Adenosina/genética , Mapeo Cromosómico/métodos , Pruebas Genéticas/métodos , Variación Genética/genética , Estudio de Asociación del Genoma Completo/métodos , Humanos , Fenotipo , Sitios de Carácter Cuantitativo/genética , Carácter Cuantitativo Heredable , Empalme del ARN/genética , Transcriptoma/genética
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