RESUMO
Circular RNAs (circRNAs) are upregulated during neurogenesis. Where and how circRNAs are localized and what roles they play during this process have remained elusive. Comparing the nuclear and cytoplasmic circRNAs between H9 cells and H9-derived forebrain (FB) neurons, we identify that a subset of adenosine (A)-rich circRNAs are restricted in H9 nuclei but exported to cytosols upon differentiation. Such a subcellular relocation of circRNAs is modulated by the poly(A)-binding protein PABPC1. In the H9 nucleus, newly produced (A)-rich circRNAs are bound by PABPC1 and trapped by the nuclear basket protein TPR to prevent their export. Modulating (A)-rich motifs in circRNAs alters their subcellular localization, and introducing (A)-rich circRNAs in H9 cytosols results in mRNA translation suppression. Moreover, decreased nuclear PABPC1 upon neuronal differentiation enables the export of (A)-rich circRNAs, including circRTN4(2,3), which is required for neurite outgrowth. These findings uncover subcellular localization features of circRNAs, linking their processing and function during neurogenesis.
Assuntos
Transporte Ativo do Núcleo Celular , Adenosina , Núcleo Celular , Neurogênese , Neurônios , Proteína I de Ligação a Poli(A) , RNA Circular , RNA , RNA Circular/metabolismo , RNA Circular/genética , Neurônios/metabolismo , Adenosina/metabolismo , Núcleo Celular/metabolismo , Humanos , Proteína I de Ligação a Poli(A)/metabolismo , Proteína I de Ligação a Poli(A)/genética , Animais , RNA/metabolismo , RNA/genética , Linhagem Celular , Diferenciação Celular , Citoplasma/metabolismo , Prosencéfalo/metabolismoRESUMO
Prolyl hydroxylase domain (PHD) proteins are oxygen sensors that use intracellular oxygen as a substrate to hydroxylate hypoxia-inducible factor (HIF) α proteins, routing them for polyubiquitylation and proteasomal degradation. Typically, HIFα accumulation in hypoxic or PHD-deficient tissues leads to upregulated angiogenesis. Here, we report unexpected retinal phenotypes associated with endothelial cell (EC)-specific gene targeting of Phd2 (Egln1) and Hif2alpha (Epas1). EC-specific Phd2 disruption suppressed retinal angiogenesis, despite HIFα accumulation and VEGFA upregulation. Suppressed retinal angiogenesis was observed both in development and in the oxygen-induced retinopathy (OIR) model. On the other hand, EC-specific deletion of Hif1alpha (Hif1a), Hif2alpha, or both did not affect retinal vascular morphogenesis. Strikingly, retinal angiogenesis appeared normal in mice double-deficient for endothelial PHD2 and HIF2α. In PHD2-deficient retinal vasculature, delta-like 4 (DLL4, a NOTCH ligand) and HEY2 (a NOTCH target) were upregulated by HIF2α-dependent mechanisms. Inhibition of NOTCH signaling by a chemical inhibitor or DLL4 antibody partially rescued retinal angiogenesis. Taken together, our data demonstrate that HIF2α accumulation in retinal ECs inhibits rather than stimulates retinal angiogenesis, in part by upregulating DLL4 expression and NOTCH signaling.
Assuntos
Animais Recém-Nascidos , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Células Endoteliais , Prolina Dioxigenases do Fator Induzível por Hipóxia , Receptores Notch , Neovascularização Retiniana , Transdução de Sinais , Regulação para Cima , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Camundongos , Receptores Notch/metabolismo , Receptores Notch/genética , Prolina Dioxigenases do Fator Induzível por Hipóxia/metabolismo , Prolina Dioxigenases do Fator Induzível por Hipóxia/genética , Neovascularização Retiniana/metabolismo , Neovascularização Retiniana/genética , Neovascularização Retiniana/patologia , Células Endoteliais/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Retina/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/genética , Vasos Retinianos/metabolismo , AngiogêneseRESUMO
Chemical reactions represent a class of quantum problems that challenge both the current theoretical understanding and computational capabilities1. Reactions that occur at ultralow temperatures provide an ideal testing ground for quantum chemistry and scattering theories, because they can be experimentally studied with unprecedented control2, yet display dynamics that are highly complex3. Here we report the full product state distribution for the reaction 2KRb â K2 + Rb2. Ultracold preparation of the reactants allows us complete control over their initial quantum degrees of freedom, whereas state-resolved, coincident detection of both products enables the probability of scattering into each of the 57 allowed rotational state-pairs to be measured. Our results show an overall agreement with a state-counting model based on statistical theory4-6, but also reveal several deviating state-pairs. In particular, we observe a strong suppression of population in the state-pair closest to the exoergicity limit as a result of the long-range potential inhibiting the escape of products. The completeness of our measurements provides a benchmark for quantum dynamics calculations beyond the current state of the art.
RESUMO
SO2 (Sulfur dioxide) is the major precursor to the production of sulfuric acid (H2SO4), contributing to acid rain and atmospheric aerosols. Sulfuric acid formed from SO2 generates light-reflecting sulfate aerosol particles in the atmosphere. This property has prompted recent geoengineering proposals to inject sulfuric acid or its precursors into the Earth's atmosphere to increase the planetary albedo to counteract global warming. SO2 oxidation in the atmosphere by the hydroxyl radical HO to form HOSO2 is a key rate-limiting step in the mechanism for forming acid rain. However, the dynamics of the HO + SO2 â HOSO2 reaction and its slow rate in the atmosphere are poorly understood to date. Herein, we use photoelectron spectroscopy of cryogenically cooled HOSO2- anion to access the neutral HOSO2 radical near the transition state of the HO + SO2 reaction. Spectroscopic and dynamic calculations are conducted on the first ab initio-based full-dimensional potential energy surface to interpret the photoelectron spectra of HOSO2- and to probe the dynamics of the HO + SO2 reaction. In addition to the finding of a unique pre-reaction complex (HOâ¯SO2) directly connected to the transition state, dynamic calculations reveal that the accessible phase space for the HO + SO2 â HOSO2 reaction is extremely narrow, forming a key reaction bottleneck and slowing the reaction rate in the atmosphere, despite the low reaction barrier. This study underlines the importance of understanding the full multidimensional potential energy surface to elucidate the dynamics of complex bimolecular reactions involving polyatomic reactants.
RESUMO
The detection of circular RNA molecules (circRNAs) is typically based on short-read RNA sequencing data processed using computational tools. Numerous such tools have been developed, but a systematic comparison with orthogonal validation is missing. Here, we set up a circRNA detection tool benchmarking study, in which 16 tools detected more than 315,000 unique circRNAs in three deeply sequenced human cell types. Next, 1,516 predicted circRNAs were validated using three orthogonal methods. Generally, tool-specific precision is high and similar (median of 98.8%, 96.3% and 95.5% for qPCR, RNase R and amplicon sequencing, respectively) whereas the sensitivity and number of predicted circRNAs (ranging from 1,372 to 58,032) are the most significant differentiators. Of note, precision values are lower when evaluating low-abundance circRNAs. We also show that the tools can be used complementarily to increase detection sensitivity. Finally, we offer recommendations for future circRNA detection and validation.
Assuntos
Benchmarking , RNA Circular , Humanos , RNA Circular/genética , RNA/genética , RNA/metabolismo , Análise de Sequência de RNA/métodosRESUMO
Most bulk-scale graphene is produced by a top-down approach, exfoliating graphite, which often requires large amounts of solvent with high-energy mixing, shearing, sonication or electrochemical treatment1-3. Although chemical oxidation of graphite to graphene oxide promotes exfoliation, it requires harsh oxidants and leaves the graphene with a defective perforated structure after the subsequent reduction step3,4. Bottom-up synthesis of high-quality graphene is often restricted to ultrasmall amounts if performed by chemical vapour deposition or advanced synthetic organic methods, or it provides a defect-ridden structure if carried out in bulk solution4-6. Here we show that flash Joule heating of inexpensive carbon sources-such as coal, petroleum coke, biochar, carbon black, discarded food, rubber tyres and mixed plastic waste-can afford gram-scale quantities of graphene in less than one second. The product, named flash graphene (FG) after the process used to produce it, shows turbostratic arrangement (that is, little order) between the stacked graphene layers. FG synthesis uses no furnace and no solvents or reactive gases. Yields depend on the carbon content of the source; when using a high-carbon source, such as carbon black, anthracitic coal or calcined coke, yields can range from 80 to 90 per cent with carbon purity greater than 99 per cent. No purification steps are necessary. Raman spectroscopy analysis shows a low-intensity or absent D band for FG, indicating that FG has among the lowest defect concentrations reported so far for graphene, and confirms the turbostratic stacking of FG, which is clearly distinguished from turbostratic graphite. The disordered orientation of FG layers facilitates its rapid exfoliation upon mixing during composite formation. The electric energy cost for FG synthesis is only about 7.2 kilojoules per gram, which could render FG suitable for use in bulk composites of plastic, metals, plywood, concrete and other building materials.
RESUMO
Since the outbreak of severe acute respiratory syndrome (SARS) 18 years ago, a large number of SARS-related coronaviruses (SARSr-CoVs) have been discovered in their natural reservoir host, bats1-4. Previous studies have shown that some bat SARSr-CoVs have the potential to infect humans5-7. Here we report the identification and characterization of a new coronavirus (2019-nCoV), which caused an epidemic of acute respiratory syndrome in humans in Wuhan, China. The epidemic, which started on 12 December 2019, had caused 2,794 laboratory-confirmed infections including 80 deaths by 26 January 2020. Full-length genome sequences were obtained from five patients at an early stage of the outbreak. The sequences are almost identical and share 79.6% sequence identity to SARS-CoV. Furthermore, we show that 2019-nCoV is 96% identical at the whole-genome level to a bat coronavirus. Pairwise protein sequence analysis of seven conserved non-structural proteins domains show that this virus belongs to the species of SARSr-CoV. In addition, 2019-nCoV virus isolated from the bronchoalveolar lavage fluid of a critically ill patient could be neutralized by sera from several patients. Notably, we confirmed that 2019-nCoV uses the same cell entry receptor-angiotensin converting enzyme II (ACE2)-as SARS-CoV.
Assuntos
Betacoronavirus/classificação , Betacoronavirus/genética , Quirópteros/virologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Surtos de Doenças , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Enzima de Conversão de Angiotensina 2 , Animais , Anticorpos Antivirais/sangue , Betacoronavirus/metabolismo , Betacoronavirus/ultraestrutura , COVID-19 , Linhagem Celular , China/epidemiologia , Chlorocebus aethiops , Feminino , Genoma Viral/genética , Humanos , Masculino , Peptidil Dipeptidase A/metabolismo , Filogenia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/classificação , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/genética , SARS-CoV-2 , Homologia de Sequência do Ácido Nucleico , Síndrome Respiratória Aguda Grave , Células VeroRESUMO
Different RNAs have distinct subcellular localizations. However, nucleotide features that determine these distinct distributions of lncRNAs and mRNAs have yet to be fully addressed. Here, we develop RNAlight, a machine learning model based on LightGBM, to identify nucleotide k-mers contributing to the subcellular localizations of mRNAs and lncRNAs. With the Tree SHAP algorithm, RNAlight extracts nucleotide features for cytoplasmic or nuclear localization of RNAs, indicating the sequence basis for distinct RNA subcellular localizations. By assembling k-mers to sequence features and subsequently mapping to known RBP-associated motifs, different types of sequence features and their associated RBPs were additionally uncovered for lncRNAs and mRNAs with distinct subcellular localizations. Finally, we extended RNAlight to precisely predict the subcellular localizations of other types of RNAs, including snRNAs, snoRNAs and different circular RNA transcripts, suggesting the generality of using RNAlight for RNA subcellular localization prediction.
Assuntos
RNA Longo não Codificante , RNA Longo não Codificante/genética , Nucleotídeos , Aprendizado de Máquina , Algoritmos , RNA Mensageiro/genéticaRESUMO
Heat shock proteins (HSPs) are a group of highly conserved proteins found in a wide range of organisms. In recent years, members of the HSP family were overexpressed in various tumors and widely involved in oncogenesis, tumor development, and therapeutic resistance. In our previous study, DNAJC24, a member of the DNAJ/HSP40 family of HSPs, was found to be closely associated with the malignant phenotype of hepatocellular carcinoma. However, its relationship with other malignancies needs to be further explored. Herein, we demonstrated that DNAJC24 exhibited upregulated expression in LUAD tissue samples and predicted poor survival in LUAD patients. The upregulation of DNAJC24 expression promoted proliferation and invasion of LUAD cells in A549 and NCI-H1299 cell lines. Further studies revealed that DNAJC24 could regulate the PI3K/AKT signaling pathway by affecting AKT phosphorylation. In addition, a series of experiments such as Co-IP and mass spectrometry confirmed that DNAJC24 could directly interact with PCNA and promoted the malignant phenotypic transformation of LUAD. In conclusion, our results suggested that DNAJC24 played an important role in the progression of LUAD and may serve as a specific prognostic biomarker for LUAD patients. The DNAJC24/PCNA/AKT axis may be a potential target for future individualized and precise treatment of LUAD patients.
Assuntos
Proliferação de Células , Proteínas de Choque Térmico HSP40 , Antígeno Nuclear de Célula em Proliferação , Proteínas Proto-Oncogênicas c-akt , Animais , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Linhagem Celular Tumoral , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Proteínas de Choque Térmico HSP40/metabolismo , Proteínas de Choque Térmico HSP40/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/genética , Camundongos Endogâmicos BALB C , Camundongos Nus , Fosforilação , Antígeno Nuclear de Célula em Proliferação/metabolismo , Antígeno Nuclear de Célula em Proliferação/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de SinaisRESUMO
Supramolecular soft crystals are periodic structures that are formed by the hierarchical assembly of complex constituents, and occur in a broad variety of 'soft-matter' systems1. Such soft crystals exhibit many of the basic features (such as three-dimensional lattices and space groups) and properties (such as band structure and wave propagation) of their 'hard-matter' atomic solid counterparts, owing to the generic symmetry-based principles that underlie both2,3. 'Mesoatomic' building blocks of soft-matter crystals consist of groups of molecules, whose sub-unit-cell configurations couple strongly to supra-unit-scale symmetry. As yet, high-fidelity experimental techniques for characterizing the detailed local structure of soft matter and, in particular, for quantifying the effects of multiscale reconfigurability are quite limited. Here, by applying slice-and-view microscopy to reconstruct the micrometre-scale domain morphology of a solution-cast block copolymer double gyroid over large specimen volumes, we unambiguously characterize its supra-unit and sub-unit cell morphology. Our multiscale analysis reveals a qualitative and underappreciated distinction between this double-gyroid soft crystal and hard crystals in terms of their structural relaxations in response to forces-namely a non-affine mode of sub-unit-cell symmetry breaking that is coherently maintained over large multicell dimensions. Subject to inevitable stresses during crystal growth, the relatively soft strut lengths and diameters of the double-gyroid network can easily accommodate deformation, while the angular geometry is stiff, maintaining local correlations even under strong symmetry-breaking distortions. These features contrast sharply with the rigid lengths and bendable angles of hard crystals.
RESUMO
After consultation with external experts, the authors acknowledged discrepancies in the classification of certain Berberis samples discussed in the article. Berberis is one of the most complex plant genera, and identifications are very hard, limited to only a handful of experts due to rampant hybridizations and other issues of reticulate evolution. This article has therefore been withdrawn at the request of the authors and with the consent of the editor until the species identification issue has been resolved. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.
RESUMO
Polymer nanofibers hold promise in a wide range of applications owing to their diverse properties, flexibility, and cost effectiveness. In this study, we introduce a polymer nanofiber drawing process in a scanning electron microscope and focused ion beam (SEM/FIB) instrument with in situ observation. We employed a nanometer-sharp tungsten needle and prepolymer microcapsules to enable nanofiber drawing in a vacuum environment. This method produces individual polymer nanofibers with diameters as small as â¼500 nm and lengths extending to millimeters, yielding nanofibers with an aspect ratio of 2000:1. The attachment to the tungsten manipulator ensures accurate transfer of the polymer nanofiber to diverse substrate types as well as fabrication of assembled structures. Our findings provide valuable insights into ultrafine polymer fiber drawing, paving the way for high-precision manipulation and assembly of polymer nanofibers.
RESUMO
Cannabinoids modulate dopamine (DA) transmission and DA-related behavior, which has been thought to be mediated initially by activation of cannabinoid CB1 receptors (CB1Rs) on GABA neurons. However, there is no behavioral evidence supporting it. In contrast, here we report that CB1Rs are also expressed in a subset of DA neurons and functionally underlie cannabinoid action in male and female mice. RNAscope in situ hybridization (ISH) assays demonstrated CB1 mRNA in tyrosine hydroxylase (TH)-positive DA neurons in the ventral tegmental area (VTA) and glutamate decarboxylase 1 (GAD1)-positive GABA neurons. The CB1R-expressing DA neurons were located mainly in the middle portion of the VTA with the number of CB1-TH colocalization progressively decreasing from the medial to the lateral VTA. Triple-staining assays indicated CB1R mRNA colocalization with both TH and vesicular glutamate transporter 2 (VgluT2, a glutamate neuronal marker) in the medial VTA close to the midline of the brain. Optogenetic activation of this population of DA neurons was rewarding as assessed by optical intracranial self-stimulation. Δ9-tetrahydrocannabinol (Δ9-THC) or ACEA (a selective CB1R agonist) dose-dependently inhibited optical intracranial self-stimulation in DAT-Cre control mice, but not in conditional knockout mice with the CB1R gene absent in DA neurons. In addition, deletion of CB1Rs from DA neurons attenuated Δ9-THC-induced reduction in DA release in the NAc, locomotion, and anxiety. Together, these findings indicate that CB1Rs are expressed in a subset of DA neurons that corelease DA and glutamate, and functionally underlie cannabinoid modulation of DA release and DA-related behavior.SIGNIFICANCE STATEMENT Cannabinoids produce a series of psychoactive effects, such as aversion, anxiety, and locomotor inhibition in rodents. However, the cellular and receptor mechanisms underlying these actions are not fully understood. Here we report that CB1 receptors are expressed not only in GABA neurons but also in a subset of dopamine neurons, which are located mainly in the medial VTA close to the midline of the midbrain and corelease dopamine and glutamate. Optogenetic activation of these dopamine neurons is rewarding, which is dose-dependently inhibited by cannabinoids. Selective deletion of CB1 receptor from dopamine neurons blocked cannabinoid-induced aversion, hypoactivity, and anxiolytic effects. These findings demonstrate that dopaminergic CB1 receptors play an important role in mediating cannabinoid action.
Assuntos
Ansiolíticos , Canabinoides , Feminino , Camundongos , Masculino , Animais , Canabinoides/farmacologia , Neurônios Dopaminérgicos/fisiologia , Ansiolíticos/farmacologia , Dronabinol/farmacologia , Dopamina/fisiologia , Receptores de Canabinoides , Área Tegmentar Ventral/fisiologia , Receptores Dopaminérgicos , Camundongos Knockout , Ácido Glutâmico/farmacologia , RNA Mensageiro , Receptor CB1 de Canabinoide/genéticaRESUMO
BACKGROUND: The stalk traits stalk diameter, stalk length, rind penetrometer resistance and dry matter content are important indicators for measuring lodging resistance. RESULTS: In this study, 377 inbred lines were used as the basic materials, and four stalk-related traits including stalk diameter, stalk length, rind penetrometer resistance and dry matter content of the third segment of maize, were investigated at the tasseling, grain filling, and maturity stages. 461,053 high-quality SNPs which were obtained by whole genome resequencing were used for genome-wide association study. As a result of mixed linear model analysis (P < 9.77 × 10-6), 29 significant SNPs related to traits were detected, accounting for 7.19% -15.03% of phenotypic variation, among which 4, 1, 4 and 20 SNPs were found related to rind penetrometer resistance, stalk diameter, stalk length, and dry matter content respectively. Most candidate genes are related to plant element structure, signal transduction mechanisms, inorganic ion transport and metabolism, nucleotide transport and metabolism, and transporter enzyme families. Comparing mixed linear model with generalized linear model, a total of 12 candidate genes were detected repeatedly, during which the candidate gene Zm00001d014449 were detected 5 times, with a phenotypic variation interpretation rate of 9.95% -10.84%. This gene is mainly expressed in cells with active cell division and tissue differentiation, and is involved in the formation of stalk vascular bundles and the synthesis of cell walls. Another candidate gene, Zm00001d005300, encodes the transcription factor MYB44, which regulates the dependence of salt stress signal phosphorylation, can effectively inhibit the accumulation of destructive reactive oxygen species, and has a certain resistance to non-biotic stress. In addition, this study also found that 10 unknown functional genes can be further Functional verification. CONCLUSIONS: This study helps to deepen the understanding of the genetic basis of traits related to maize stalk lodging resistance, and provides theoretical guidance for future maize lodging resistance breeding.
Assuntos
Estudo de Associação Genômica Ampla , Zea mays , Zea mays/genética , Melhoramento Vegetal , Fenótipo , Genes de Plantas , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Evidence from epidemiological studies suggests that hearing loss is associated with an accelerated decline in cognitive function, but the underlying pathophysiological mechanism remains poorly understood. Studies using auditory tasks have suggested that degraded auditory input increases the cognitive load for auditory perceptual processing and thereby reduces the resources available for other cognitive tasks. Attention-related networks are among the systems overrecruited to support degraded auditory perception, but it is unclear how they function when no excessive recruitment of cognitive resources for auditory processing is needed. Here, we implemented an EEG study using a nonauditory visual attentional selection task in 30 individuals with age-related hearing loss (ARHLs, 60-73 years) and compared them with aged (N = 30, 60-70 years) and young (N = 35, 22-29 years) normal-hearing controls. Compared with their normal-hearing peers, ARHLs demonstrated a significant amplitude reduction for the posterior contralateral N2 component, which is a well-validated index of the allocation of selective visual attention, despite the comparable behavioral performance. Furthermore, the amplitudes were observed to correlate significantly with hearing acuities (pure tone audiometry thresholds) and higher-order hearing abilities (speech-in-noise thresholds) in aged individuals. The target-elicited alpha lateralization, another mechanism of visuospatial attention, demonstrated in control groups was not observed in ARHLs. Although behavioral performance is comparable, the significant decrease in N2pc amplitude in ARHLs provides neurophysiologic evidence that may suggest a visual attentional deficit in ARHLs even without extra-recruitment of cognitive resources by auditory processing. It supports the hypothesis that constant degraded auditory input in ARHLs has an adverse impact on the function of cognitive control systems, which is a possible mechanism mediating the relationship between hearing loss and cognitive decline.
RESUMO
The activation of carbon dioxide (CO2) by a transition-metal cation in the gas phase is a unique model system for understanding single-atom catalysis. The mechanism of such reactions is often attributed to a "two-state reactivity" model in which the high-energy barrier of a spin state correlating with ground-state reactants is avoided by intersystem crossing (ISC) to a different spin state with a lower barrier. However, such a "spin-forbidden" mechanism, along with the corresponding dynamics, has seldom been rigorously examined theoretically, due to the lack of global potential energy surfaces (PESs). In this work, we report full-dimensional PESs of the lowest-lying quintet, triplet, and singlet states of the TaCO2+ system, machine-learned from first-principles data. These PESs and the corresponding spin-orbit couplings enable us to provide an extensive theoretical characterization of the dynamics and kinetics of the reaction between the tantalum cation (Ta+) and CO2, which have recently been investigated experimentally at high collision energies using crossed beams and velocity map imaging, as well as at thermal energies using a selected-ion flow tube apparatus. The multistate quasi-classical trajectory simulations with surface hopping reproduce most of the measured product translational and angular distributions, shedding valuable light on the nonadiabatic reaction dynamics. The calculated rate coefficients from 200 to 600 K are also in good agreement with the latest experimental measurements. More importantly, these calculations revealed that the reaction is controlled by intersystem crossing, rather than potential barriers.
RESUMO
BACKGROUND: Although DHFR gene amplification has long been known as a major mechanism for methotrexate (MTX) resistance in cancer, the early changes and detailed development of the resistance are not yet fully understood. METHODS: We performed genomic, transcriptional and proteomic analyses of human colon cancer cells with sequentially increasing levels of MTX-resistance. RESULTS: The genomic amplification evolved in three phases (pre-amplification, homogenously staining region (HSR) and extrachromosomal DNA (ecDNA)). We confirm that genomic amplification and increased expression of DHFR, with formation of HSRs and especially ecDNAs, is the major driver of resistance. However, DHFR did not play a detectable role in the early phase. In the late phase (ecDNA), increase in FAM151B protein level may also have an important role by decreasing sensitivity to MTX. In addition, although MSH3 and ZFYVE16 may be subject to different posttranscriptional regulations and therefore protein expressions are decreased in ecDNA stages compared to HSR stages, they still play important roles in MTX resistance. CONCLUSION: The study provides a detailed evolutionary trajectory of MTX-resistance and identifies new targets, especially ecDNAs, which could help to prevent drug resistance. It also presents a proof-of-principal approach which could be applied to other cancer drug resistance studies.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Amplificação de Genes , Metotrexato , Tetra-Hidrofolato Desidrogenase , Humanos , Metotrexato/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Tetra-Hidrofolato Desidrogenase/genética , Tetra-Hidrofolato Desidrogenase/metabolismo , Linhagem Celular Tumoral , Neoplasias do Colo/genética , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/patologia , Antimetabólitos Antineoplásicos/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Genômica/métodosRESUMO
Cytochrome P450s are a large family of protein-encoding genes in plant genomes, many of which have not yet been comprehensively characterized. Here, a novel P450 gene, CYP82D47, was isolated and functionally characterized from cucumber (Cucumis sativus L.). Quantitative real-time reverse-transcription polymerase chain reaction analysis revealed that CYP82D47 expression was triggered by salicylic acid (SA) and ethephon (ETH). Expression analysis revealed a correlation between CYP82D47 transcript levels and plant defense responses against powdery mildew (PM) and Fusarium oxysporum f. sp. cucumerinum (Foc). Although no significant differences were observed in disease resistance between CYP82D47-RNAi and wild-type cucumber, overexpression (OE) of CYP82D47 enhanced PM and Foc resistance in cucumber. Furthermore, the expression levels of SA-related genes (PR1, PR2, PR4, and PR5) increased in CYP82D47-overexpressing plants 7 days post fungal inoculation. The levels of ETH-related genes (EIN3 and EBF2) were similarly upregulated. The observed enhanced resistance was associated with the upregulation of SA/ETH-signaling-dependent defense genes. These findings indicate the crucial role of CYP82D47 in pathogen defense in cucumber. CYP82D47-overexpressing cucumber plants exhibited heightened susceptibility to both diseases. The study results offer important insights that could aid in the development of disease-resistant cucumber cultivars and elucidate the molecular mechanisms associated with the functions of CYP82D47.
Assuntos
Cucumis sativus , Fusarium , Compostos Organofosforados , Cucumis sativus/genética , Regulação para Cima , Resistência à Doença/genética , Ácido Salicílico/farmacologiaRESUMO
BACKGROUND: In this study, we aimed to evaluate the efficacy, safety, and tolerability of atogepant for the preventive treatment of chronic migraine. METHODS: We did this randomised, double-blind, placebo-controlled, phase 3 trial at 142 clinical research sites across the USA, the UK, Canada, China, Czech Republic, Denmark, France, Germany, Italy, Japan, South Korea, Poland, Russia, Spain, Sweden, and Taiwan. Adults aged 18-80 years with a 1-year or longer history of chronic migraine were randomly assigned (1:1:1) to receive oral atogepant 30 mg twice a day, oral atogepant 60 mg once a day, or placebo. The primary endpoint was change from baseline in mean monthly migraine days (MMDs) across the 12-week treatment period. The primary analysis was done in the modified intent-to-treat population and included all randomly assigned participants who received at least one dose of study intervention, had an evaluable baseline period of electronic diary (eDiary) data, and had at least one evaluable post-baseline 4-week period (weeks 1-4, 5-8, and 9-12) of eDiary data during the double-blind period. The safety population consisted of all participants who received at least one dose of study intervention. This trial is registered with ClinicalTrials.gov (NCT03855137). FINDINGS: Between March 11, 2019 and Jan 20, 2022, 1489 participants were assessed for eligibility. 711 were excluded, and 778 participants were randomly assigned to atogepant 30 mg twice a day (n=257), atogepant 60 mg once a day (n=262), or placebo (n=259). Participants in the safety population were aged 18-74 years (mean 42·1 years). 459 (59%) of 773 patients were White, 677 (88%) patients were female, and 96 (12%) were male. 84 participants discontinued treatment during the trial, and 755 comprised the modified intent-to-treat population (atogepant 30 mg twice a day n=253, atogepant 60 mg once a day n=256, and placebo n=246). Baseline mean number of MMDs were 18·6 (SE 5·1) with atogepant 30 mg twice a day, 19·2 (5·3) with atogepant 60 mg once a day, and 18·9 (4·8) with placebo. Change from baseline in mean MMDs across 12 weeks was -7·5 (SE 0·4) with atogepant 30 mg twice a day, -6·9 (0·4) with atogepant 60 mg once a day, and -5·1 (0·4) with placebo. Least squares mean difference from placebo was -2·4 with atogepant 30 mg twice a day (95% CI -3·5 to -1·3; adjusted p<0·0001) and -1·8 with atogepant 60 mg once a day (-2·9 to -0·8; adjusted p=0·0009). Most common adverse events for atogepant were constipation (30 mg twice a day 28 [10·9%]; 60 mg once a day 26 [10%]; and placebo 8 [3%]) and nausea (30 mg twice a day 20 [8%]; 60 mg once a day 25 [10%]; and placebo 9 [4%]). Potentially clinically significant weight decrease (≥7% reduction at any time post-baseline) was observed in each treatment group (atogepant 30 mg twice a day 14 [6%]; atogepant 60 mg once a day 15 [6%]; and placebo 5 [2%]). INTERPRETATION: Atogepant 30 mg twice a day and 60 mg once a day showed clinically relevant reductions in MMDs across 12 weeks in chronic migraine patients. Both atogepant doses were well tolerated, consistent with the known safety profile of atogepant. FUNDING: Allergan (now AbbVie).
Assuntos
Transtornos de Enxaqueca , Adulto , Humanos , Masculino , Feminino , Resultado do Tratamento , Transtornos de Enxaqueca/tratamento farmacológico , Transtornos de Enxaqueca/prevenção & controle , Método Duplo-Cego , CanadáRESUMO
BACKGROUND: Atogepant is an oral, small-molecule, calcitonin gene-related peptide receptor antagonist that is being investigated for the preventive treatment of migraine. METHODS: In a phase 3, double-blind trial, we randomly assigned adults with 4 to 14 migraine days per month in a 1:1:1:1 ratio to receive a once-daily dose of oral atogepant (10 mg, 30 mg, or 60 mg) or placebo for 12 weeks. The primary end point was the change from baseline in the mean number of migraine days per month across the 12 weeks. Secondary end points included headache days per month, a reduction from baseline of at least 50% in the 3-month average of migraine days per month, quality of life, and scores on the Activity Impairment in Migraine-Diary (AIM-D). RESULTS: A total of 2270 participants were screened, 910 were enrolled, and 873 were included in the efficacy analysis; 214 were assigned to the 10-mg atogepant group, 223 to the 30-mg atogepant group, 222 to the 60-mg atogepant group, and 214 to the placebo group. The mean number of migraine days per month at baseline ranged from 7.5 to 7.9 in the four groups. The changes from baseline across 12 weeks were -3.7 days with 10-mg atogepant, -3.9 days with 30-mg atogepant, -4.2 days with 60-mg atogepant, and -2.5 days with placebo. The mean differences from placebo in the change from baseline were -1.2 days with 10-mg atogepant (95% confidence interval [CI], -1.8 to -0.6), -1.4 days with 30-mg atogepant (95% CI, -1.9 to -0.8), and -1.7 days with 60-mg atogepant (95% CI, -2.3 to -1.2) (P<0.001 for all comparisons with placebo). Results for the secondary end points favored atogepant over placebo with the exceptions of the AIM-D Performance of Daily Activities score and the AIM-D Physical Impairment score for the 10-mg dose. The most common adverse events were constipation (6.9 to 7.7% across atogepant doses) and nausea (4.4 to 6.1% across atogepant doses). Serious adverse events included one case each of asthma and optic neuritis in the 10-mg atogepant group. CONCLUSIONS: Oral atogepant once daily was effective in reducing the number of migraine days and headache days over a period of 12 weeks. Adverse events included constipation and nausea. Longer and larger trials are needed to determine the effect and safety of atogepant for migraine prevention. (Funded by Allergan; ADVANCE ClinicalTrials.gov number, NCT03777059.).