Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.058
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Cell ; 186(21): 4597-4614.e26, 2023 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-37738970

RESUMO

SARS-CoV-2 variants of concern (VOCs) emerged during the COVID-19 pandemic. Here, we used unbiased systems approaches to study the host-selective forces driving VOC evolution. We discovered that VOCs evolved convergent strategies to remodel the host by modulating viral RNA and protein levels, altering viral and host protein phosphorylation, and rewiring virus-host protein-protein interactions. Integrative computational analyses revealed that although Alpha, Beta, Gamma, and Delta ultimately converged to suppress interferon-stimulated genes (ISGs), Omicron BA.1 did not. ISG suppression correlated with the expression of viral innate immune antagonist proteins, including Orf6, N, and Orf9b, which we mapped to specific mutations. Later Omicron subvariants BA.4 and BA.5 more potently suppressed innate immunity than early subvariant BA.1, which correlated with Orf6 levels, although muted in BA.4 by a mutation that disrupts the Orf6-nuclear pore interaction. Our findings suggest that SARS-CoV-2 convergent evolution overcame human adaptive and innate immune barriers, laying the groundwork to tackle future pandemics.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , COVID-19/virologia , Imunidade Inata/genética , Pandemias , SARS-CoV-2/genética
2.
Cell ; 185(9): 1539-1548.e5, 2022 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-35429436

RESUMO

Virus-like particle (VLP) and live virus assays were used to investigate neutralizing immunity against Delta and Omicron SARS-CoV-2 variants in 259 samples from 128 vaccinated individuals. Following Delta breakthrough infection, titers against WT rose 57-fold and 3.1-fold compared with uninfected boosted and unboosted individuals, respectively, versus only a 5.8-fold increase and 3.1-fold decrease for Omicron breakthrough infection. Among immunocompetent, unboosted patients, Delta breakthrough infections induced 10.8-fold higher titers against WT compared with Omicron (p = 0.037). Decreased antibody responses in Omicron breakthrough infections relative to Delta were potentially related to a higher proportion of asymptomatic or mild breakthrough infections (55.0% versus 28.6%, respectively), which exhibited 12.3-fold lower titers against WT compared with moderate to severe infections (p = 0.020). Following either Delta or Omicron breakthrough infection, limited variant-specific cross-neutralizing immunity was observed. These results suggest that Omicron breakthrough infections are less immunogenic than Delta, thus providing reduced protection against reinfection or infection from future variants.


Assuntos
COVID-19 , SARS-CoV-2 , Anticorpos Neutralizantes , Anticorpos Antivirais , Vacina BNT162 , COVID-19/imunologia , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Humanos
3.
Nature ; 607(7918): 351-355, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35584773

RESUMO

SARS-CoV-2 Delta and Omicron are globally relevant variants of concern. Although individuals infected with Delta are at risk of developing severe lung disease, infection with Omicron often causes milder symptoms, especially in vaccinated individuals1,2. The question arises of whether widespread Omicron infections could lead to future cross-variant protection, accelerating the end of the pandemic. Here we show that without vaccination, infection with Omicron induces a limited humoral immune response in mice and humans. Sera from mice overexpressing the human ACE2 receptor and infected with Omicron neutralize only Omicron, but not other variants of concern, whereas broader cross-variant neutralization was observed after WA1 and Delta infections. Unlike WA1 and Delta, Omicron replicates to low levels in the lungs and brains of infected animals, leading to mild disease with reduced expression of pro-inflammatory cytokines and diminished activation of lung-resident T cells. Sera from individuals who were unvaccinated and infected with Omicron show the same limited neutralization of only Omicron itself. By contrast, Omicron breakthrough infections induce overall higher neutralization titres against all variants of concern. Our results demonstrate that Omicron infection enhances pre-existing immunity elicited by vaccines but, on its own, may not confer broad protection against non-Omicron variants in unvaccinated individuals.


Assuntos
COVID-19 , Proteção Cruzada , SARS-CoV-2 , Vacinação , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , COVID-19/virologia , Vacinas contra COVID-19/administração & dosagem , Proteção Cruzada/imunologia , Citocinas , Humanos , Camundongos , SARS-CoV-2/classificação , SARS-CoV-2/imunologia , Vacinação/estatística & dados numéricos
4.
Nature ; 597(7876): 376-380, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34471286

RESUMO

Pleistocene hominin dispersals out of, and back into, Africa necessarily involved traversing the diverse and often challenging environments of Southwest Asia1-4. Archaeological and palaeontological records from the Levantine woodland zone document major biological and cultural shifts, such as alternating occupations by Homo sapiens and Neanderthals. However, Late Quaternary cultural, biological and environmental records from the vast arid zone that constitutes most of Southwest Asia remain scarce, limiting regional-scale insights into changes in hominin demography and behaviour1,2,5. Here we report a series of dated palaeolake sequences, associated with stone tool assemblages and vertebrate fossils, from the Khall Amayshan 4 and Jubbah basins in the Nefud Desert. These findings, including the oldest dated hominin occupations in Arabia, reveal at least five hominin expansions into the Arabian interior, coinciding with brief 'green' windows of reduced aridity approximately 400, 300, 200, 130-75 and 55 thousand years ago. Each occupation phase is characterized by a distinct form of material culture, indicating colonization by diverse hominin groups, and a lack of long-term Southwest Asian population continuity. Within a general pattern of African and Eurasian hominin groups being separated by Pleistocene Saharo-Arabian aridity, our findings reveal the tempo and character of climatically modulated windows for dispersal and admixture.


Assuntos
Hominidae , Migração Humana/história , Animais , Antropologia , Arábia , Ásia , História Antiga , Paleontologia , Comportamento de Utilização de Ferramentas
5.
Mol Cell ; 76(1): 82-95.e7, 2019 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-31474574

RESUMO

SF3B1, which encodes an essential spliceosomal protein, is frequently mutated in myelodysplastic syndromes (MDS) and many cancers. However, the defect of mutant SF3B1 is unknown. Here, we analyzed RNA sequencing data from MDS patients and confirmed that SF3B1 mutants use aberrant 3' splice sites. To elucidate the underlying mechanism, we purified complexes containing either wild-type or the hotspot K700E mutant SF3B1 and found that levels of a poorly studied spliceosomal protein, SUGP1, were reduced in mutant spliceosomes. Strikingly, SUGP1 knockdown completely recapitulated the splicing errors, whereas SUGP1 overexpression drove the protein, which our data suggest plays an important role in branchsite recognition, into the mutant spliceosome and partially rescued splicing. Other hotspot SF3B1 mutants showed similar altered splicing and diminished interaction with SUGP1. Our study demonstrates that SUGP1 loss is a common defect of spliceosomes with disease-causing SF3B1 mutations and, because this defect can be rescued, suggests possibilities for therapeutic intervention.


Assuntos
Leucemia Eritroblástica Aguda/metabolismo , Mutação , Síndromes Mielodisplásicas/metabolismo , Fosfoproteínas/metabolismo , Fatores de Processamento de RNA/metabolismo , Splicing de RNA , Spliceossomos/metabolismo , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Células HEK293 , Humanos , Células K562 , Leucemia Eritroblástica Aguda/genética , Leucemia Eritroblástica Aguda/patologia , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/patologia , Fenótipo , Fosfoproteínas/genética , Ligação Proteica , Fatores de Processamento de RNA/genética , Spliceossomos/genética , Spliceossomos/patologia
6.
N Engl J Med ; 389(4): 335-347, 2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37272512

RESUMO

BACKGROUND: Ciltacabtagene autoleucel (cilta-cel), a B-cell maturation antigen (BCMA)-directed CAR T-cell therapy, is effective in heavily pretreated patients with relapsed or refractory multiple myeloma. We investigated cilta-cel in earlier treatment lines in patients with lenalidomide-refractory disease. METHODS: In this phase 3, randomized, open-label trial, we assigned patients with lenalidomide-refractory multiple myeloma to receive cilta-cel or the physician's choice of effective standard care. All the patients had received one to three previous lines of treatment. The primary outcome was progression-free survival. RESULTS: A total of 419 patients underwent randomization (208 to receive cilta-cel and 211 to receive standard care). At a median follow-up of 15.9 months (range, 0.1 to 27.3), the median progression-free survival was not reached in the cilta-cel group and was 11.8 months in the standard-care group (hazard ratio, 0.26; 95% confidence interval [CI], 0.18 to 0.38; P<0.001). Progression-free survival at 12 months was 75.9% (95% CI, 69.4 to 81.1) in the cilta-cel group and 48.6% (95% CI, 41.5 to 55.3) in the standard-care group. More patients in the cilta-cel group than in the standard-care group had an overall response (84.6% vs. 67.3%), a complete response or better (73.1% vs. 21.8%), and an absence of minimal residual disease (60.6% vs. 15.6%). Death from any cause was reported in 39 patients and 46 patients, respectively (hazard ratio, 0.78; 95% CI, 0.5 to 1.2). Most patients reported grade 3 or 4 adverse events during treatment. Among the 176 patients who received cilta-cel in the as-treated population, 134 (76.1%) had cytokine release syndrome (grade 3 or 4, 1.1%; no grade 5), 8 (4.5%) had immune effector cell-associated neurotoxicity syndrome (all grade 1 or 2), 1 had movement and neurocognitive symptoms (grade 1), 16 (9.1%) had cranial nerve palsy (grade 2, 8.0%; grade 3, 1.1%), and 5 (2.8%) had CAR-T-related peripheral neuropathy (grade 1 or 2, 2.3%; grade 3, 0.6%). CONCLUSIONS: A single cilta-cel infusion resulted in a lower risk of disease progression or death than standard care in lenalidomide-refractory patients with multiple myeloma who had received one to three previous therapies. (Funded by Janssen and Legend Biotech; CARTITUDE-4 ClinicalTrials.gov number, NCT04181827.).


Assuntos
Antineoplásicos Imunológicos , Antígeno de Maturação de Linfócitos B , Imunoterapia Adotiva , Mieloma Múltiplo , Humanos , Lenalidomida/efeitos adversos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/mortalidade , Síndromes Neurotóxicas , Intervalo Livre de Progressão , Antígeno de Maturação de Linfócitos B/imunologia , Imunoterapia Adotiva/métodos , Antineoplásicos Imunológicos/uso terapêutico , Resistencia a Medicamentos Antineoplásicos
7.
Nucleic Acids Res ; 52(11): 6647-6661, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38587193

RESUMO

The viral genome of SARS-CoV-2 is packaged by the nucleocapsid (N-)protein into ribonucleoprotein particles (RNPs), 38 ± 10 of which are contained in each virion. Their architecture has remained unclear due to the pleomorphism of RNPs, the high flexibility of N-protein intrinsically disordered regions, and highly multivalent interactions between viral RNA and N-protein binding sites in both N-terminal (NTD) and C-terminal domain (CTD). Here we explore critical interaction motifs of RNPs by applying a combination of biophysical techniques to ancestral and mutant proteins binding different nucleic acids in an in vitro assay for RNP formation, and by examining nucleocapsid protein variants in a viral assembly assay. We find that nucleic acid-bound N-protein dimers oligomerize via a recently described protein-protein interface presented by a transient helix in its long disordered linker region between NTD and CTD. The resulting hexameric complexes are stabilized by multivalent protein-nucleic acid interactions that establish crosslinks between dimeric subunits. Assemblies are stabilized by the dimeric CTD of N-protein offering more than one binding site for stem-loop RNA. Our study suggests a model for RNP assembly where N-protein scaffolding at high density on viral RNA is followed by cooperative multimerization through protein-protein interactions in the disordered linker.


Assuntos
Proteínas do Nucleocapsídeo de Coronavírus , Multimerização Proteica , RNA Viral , SARS-CoV-2 , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , SARS-CoV-2/química , Proteínas do Nucleocapsídeo de Coronavírus/química , Proteínas do Nucleocapsídeo de Coronavírus/metabolismo , Proteínas do Nucleocapsídeo de Coronavírus/genética , RNA Viral/metabolismo , RNA Viral/química , RNA Viral/genética , Ligação Proteica , Sítios de Ligação , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/genética , Montagem de Vírus/genética , Humanos , Proteínas do Nucleocapsídeo/química , Proteínas do Nucleocapsídeo/metabolismo , Proteínas do Nucleocapsídeo/genética , Modelos Moleculares , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , COVID-19/virologia
8.
N Engl J Med ; 387(2): 132-147, 2022 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-35660812

RESUMO

BACKGROUND: In patients with newly diagnosed multiple myeloma, the effect of adding autologous stem-cell transplantation (ASCT) to triplet therapy (lenalidomide, bortezomib, and dexamethasone [RVD]), followed by lenalidomide maintenance therapy until disease progression, is unknown. METHODS: In this phase 3 trial, adults (18 to 65 years of age) with symptomatic myeloma received one cycle of RVD. We randomly assigned these patients, in a 1:1 ratio, to receive two additional RVD cycles plus stem-cell mobilization, followed by either five additional RVD cycles (the RVD-alone group) or high-dose melphalan plus ASCT followed by two additional RVD cycles (the transplantation group). Both groups received lenalidomide until disease progression, unacceptable side effects, or both. The primary end point was progression-free survival. RESULTS: Among 357 patients in the RVD-alone group and 365 in the transplantation group, at a median follow-up of 76.0 months, 328 events of disease progression or death occurred; the risk was 53% higher in the RVD-alone group than in the transplantation group (hazard ratio, 1.53; 95% confidence interval [CI], 1.23 to 1.91; P<0.001); median progression-free survival was 46.2 months and 67.5 months. The percentage of patients with a partial response or better was 95.0% in the RVD-alone group and 97.5% in the transplantation group (P = 0.55); 42.0% and 46.8%, respectively, had a complete response or better (P = 0.99). Treatment-related adverse events of grade 3 or higher occurred in 78.2% and 94.2%, respectively; 5-year survival was 79.2% and 80.7% (hazard ratio for death, 1.10; 95% CI, 0.73 to 1.65). CONCLUSIONS: Among adults with multiple myeloma, RVD plus ASCT was associated with longer progression-free survival than RVD alone. No overall survival benefit was observed. (Funded by the National Heart, Lung, and Blood Institute and others; DETERMINATION ClinicalTrials.gov number, NCT01208662.).


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Quimioterapia de Manutenção , Mieloma Múltiplo , Transplante de Células-Tronco , Adulto , Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Bortezomib/administração & dosagem , Bortezomib/efeitos adversos , Dexametasona/administração & dosagem , Dexametasona/efeitos adversos , Progressão da Doença , Intervalo Livre de Doença , Humanos , Lenalidomida/administração & dosagem , Lenalidomida/efeitos adversos , Quimioterapia de Manutenção/métodos , Melfalan/administração & dosagem , Mieloma Múltiplo/diagnóstico , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/cirurgia , Transplante Autólogo
9.
Nature ; 565(7738): 230-233, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30602788

RESUMO

Yemen is currently experiencing, to our knowledge, the largest cholera epidemic in recent history. The first cases were declared in September 2016, and over 1.1 million cases and 2,300 deaths have since been reported1. Here we investigate the phylogenetic relationships, pathogenesis and determinants of antimicrobial resistance by sequencing the genomes of Vibrio cholerae isolates from the epidemic in Yemen and recent isolates from neighbouring regions. These 116 genomic sequences were placed within the phylogenetic context of a global collection of 1,087 isolates of the seventh pandemic V. cholerae serogroups O1 and O139 biotype El Tor2-4. We show that the isolates from Yemen that were collected during the two epidemiological waves of the epidemic1-the first between 28 September 2016 and 23 April 2017 (25,839 suspected cases) and the second beginning on 24 April 2017 (more than 1 million suspected cases)-are V. cholerae serotype Ogawa isolates from a single sublineage of the seventh pandemic V. cholerae O1 El Tor (7PET) lineage. Using genomic approaches, we link the epidemic in Yemen to global radiations of pandemic V. cholerae and show that this sublineage originated from South Asia and that it caused outbreaks in East Africa before appearing in Yemen. Furthermore, we show that the isolates from Yemen are susceptible to several antibiotics that are commonly used to treat cholera and to polymyxin B, resistance to which is used as a marker of the El Tor biotype.


Assuntos
Cólera/epidemiologia , Cólera/microbiologia , Genoma Bacteriano/genética , Genômica , Vibrio cholerae/genética , Vibrio cholerae/isolamento & purificação , Humanos , Filogenia , Vibrio cholerae/classificação , Iêmen/epidemiologia
11.
Proc Natl Acad Sci U S A ; 119(1)2022 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-34930825

RESUMO

SF3B1 is the most frequently mutated RNA splicing factor in cancer, including in ∼25% of myelodysplastic syndromes (MDS) patients. SF3B1-mutated MDS, which is strongly associated with ringed sideroblast morphology, is characterized by ineffective erythropoiesis, leading to severe, often fatal anemia. However, functional evidence linking SF3B1 mutations to the anemia described in MDS patients harboring this genetic aberration is weak, and the underlying mechanism is completely unknown. Using isogenic SF3B1 WT and mutant cell lines, normal human CD34 cells, and MDS patient cells, we define a previously unrecognized role of the kinase MAP3K7, encoded by a known mutant SF3B1-targeted transcript, in controlling proper terminal erythroid differentiation, and show how MAP3K7 missplicing leads to the anemia characteristic of SF3B1-mutated MDS, although not to ringed sideroblast formation. We found that p38 MAPK is deactivated in SF3B1 mutant isogenic and patient cells and that MAP3K7 is an upstream positive effector of p38 MAPK. We demonstrate that disruption of this MAP3K7-p38 MAPK pathway leads to premature down-regulation of GATA1, a master regulator of erythroid differentiation, and that this is sufficient to trigger accelerated differentiation, erythroid hyperplasia, and ultimately apoptosis. Our findings thus define the mechanism leading to the severe anemia found in MDS patients harboring SF3B1 mutations.


Assuntos
Anemia/metabolismo , Eritropoese , MAP Quinase Quinase Quinases/metabolismo , Sistema de Sinalização das MAP Quinases , Mutação , Síndromes Mielodisplásicas/metabolismo , Fosfoproteínas/metabolismo , Fatores de Processamento de RNA/metabolismo , Anemia/genética , Anemia/patologia , Diferenciação Celular/genética , Células Eritroides/metabolismo , Células Eritroides/patologia , Humanos , Células K562 , MAP Quinase Quinase Quinases/genética , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/patologia , Fosfoproteínas/genética , Fatores de Processamento de RNA/genética , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
12.
Proc Natl Acad Sci U S A ; 119(31): e2200592119, 2022 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-35858386

RESUMO

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant contains extensive sequence changes relative to the earlier-arising B.1, B.1.1, and Delta SARS-CoV-2 variants that have unknown effects on viral infectivity and response to existing vaccines. Using SARS-CoV-2 virus-like particles (VLPs), we examined mutations in all four structural proteins and found that Omicron and Delta showed 4.6-fold higher luciferase delivery overall relative to the ancestral B.1 lineage, a property conferred mostly by enhancements in the S and N proteins, while mutations in M and E were mostly detrimental to assembly. Thirty-eight antisera samples from individuals vaccinated with Pfizer/BioNTech, Moderna, or Johnson & Johnson vaccines and convalescent sera from unvaccinated COVID-19 survivors had 15-fold lower efficacy to prevent cell transduction by VLPs containing the Omicron mutations relative to the ancestral B.1 spike protein. A third dose of Pfizer vaccine elicited substantially higher neutralization titers against Omicron, resulting in detectable neutralizing antibodies in eight out of eight subjects compared to one out of eight preboosting. Furthermore, the monoclonal antibody therapeutics casirivimab and imdevimab had robust neutralization activity against B.1 and Delta VLPs but no detectable neutralization of Omicron VLPs, while newly authorized bebtelovimab maintained robust neutralization across variants. Our results suggest that Omicron has similar assembly efficiency and cell entry compared to Delta and that its rapid spread is due mostly to reduced neutralization in sera from previously vaccinated subjects. In addition, most currently available monoclonal antibodies will not be useful in treating Omicron-infected patients with the exception of bebtelovimab.


Assuntos
Anticorpos Monoclonais Humanizados , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19 , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Anticorpos Monoclonais Humanizados/uso terapêutico , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/uso terapêutico , COVID-19/terapia , COVID-19/virologia , Humanos , Mutação , SARS-CoV-2/genética , SARS-CoV-2/patogenicidade , Glicoproteína da Espícula de Coronavírus/genética
13.
J Biol Chem ; 299(12): 105362, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37863261

RESUMO

The nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) compacts the RNA genome into viral ribonucleoprotein (vRNP) complexes within virions. Assembly of vRNPs is inhibited by phosphorylation of the N protein serine/arginine (SR) region. Several SARS-CoV-2 variants of concern carry N protein mutations that reduce phosphorylation and enhance the efficiency of viral packaging. Variants of the dominant B.1.1 viral lineage also encode a truncated N protein, termed N∗ or Δ(1-209), that mediates genome packaging despite lacking the N-terminal RNA-binding domain and SR region. Here, we use mass photometry and negative stain electron microscopy to show that purified Δ(1-209) and viral RNA assemble into vRNPs that are remarkably similar in size and shape to those formed with full-length N protein. We show that assembly of Δ(1-209) vRNPs requires the leucine-rich helix of the central disordered region and that this helix promotes N protein oligomerization. We also find that fusion of a phosphomimetic SR region to Δ(1-209) inhibits RNA binding and vRNP assembly. Our results provide new insights into the mechanisms by which RNA binding promotes N protein self-association and vRNP assembly, and how this process is modulated by phosphorylation.


Assuntos
Proteínas do Nucleocapsídeo , SARS-CoV-2 , Humanos , COVID-19/virologia , Proteínas do Nucleocapsídeo/genética , Proteínas do Nucleocapsídeo/metabolismo , Proteínas do Nucleocapsídeo/ultraestrutura , RNA Viral/metabolismo , RNA Viral/ultraestrutura , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , SARS-CoV-2/ultraestrutura , Fosforilação , Montagem de Vírus/genética
14.
J Am Chem Soc ; 146(11): 7341-7351, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38442250

RESUMO

The C2H2 separation from CO2 and C2H4 is of great importance yet highly challenging in the petrochemical industry, owing to their similar physical and chemical properties. Herein, the pore nanospace engineering of cage-like mixed-ligand MFOF-1 has been accomplished via contracting the size of the pyridine- and carboxylic acid-functionalized linkers and introducing a fluoride- and sulfate-bridging cobalt cluster, based on a reticular chemistry strategy. Compared with the prototypical MFOF-1, the constructed FJUT-1 with the same topology presents significantly improved C2H2 adsorption capacity, and selective C2H2 separation performance due to the reduced cage cavity size, functionalized pore surface, and appropriate pore volume. The introduction of fluoride- and sulfate-bridging cubane-type tetranuclear cobalt clusters bestows FJUT-1 with exceptional chemical stability under harsh conditions while providing multiple potential C2H2 binding sites, thus rendering the adequate ability for practical C2H2 separation application as confirmed by the dynamic breakthrough experiments under dry and humid conditions. Additionally, the distinct binding mechanism is suggested by theoretical calculations in which the multiple supramolecular interactions involving C-H···O, C-H···F, and other van der Waals forces play a critical role in the selective C2H2 separation.

15.
J Am Chem Soc ; 146(35): 24537-24552, 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39167680

RESUMO

The envelope (E) protein of SARS-CoV-2 is the smallest of the three structural membrane proteins of the virus. E mediates budding of the progeny virus in the endoplasmic reticulum Golgi intermediate compartment of the cell. It also conducts ions, and this channel activity is associated with the pathogenicity of SARS-CoV-2. The structural basis for these functions is still poorly understood. Biochemical studies of E in detergent micelles found a variety of oligomeric states, but recent 19F solid-state NMR data indicated that the transmembrane domain (ETM, residues 8-38) forms pentamers in lipid bilayers. Hexamethylene amiloride (HMA), an E inhibitor, binds the pentameric ETM at the lipid-exposed helix-helix interface. Here, we investigate the oligomeric structure and drug interaction of an ectodomain-containing E construct, ENTM (residues 1-41). Unexpectedly, 19F spin diffusion NMR data reveal that ENTM adopts an average oligomeric state of dimers instead of pentamers in lipid bilayers. A new amiloride inhibitor, AV-352, shows stronger inhibitory activity than HMA in virus-like particle assays. Distance measurements between 13C-labeled protein and a trifluoromethyl group of AV-352 indicate that the drug binds ENTM with a higher stoichiometry than ETM. We measured protein-drug contacts using a sensitivity-enhanced two-dimensional 13C-19F distance NMR technique. The results indicate that AV-352 binds the C-terminal half of the TM domain, similar to the binding region of HMA. These data provide evidence for the existence of multiple oligomeric states of E in lipid bilayers, which may carry out distinct functions and may be differentially targeted by antiviral drugs.


Assuntos
Amilorida , Proteínas do Envelope de Coronavírus , SARS-CoV-2 , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/química , SARS-CoV-2/metabolismo , Amilorida/farmacologia , Amilorida/química , Amilorida/análogos & derivados , Proteínas do Envelope de Coronavírus/química , Proteínas do Envelope de Coronavírus/metabolismo , Domínios Proteicos , Humanos , Ligação Proteica , Antivirais/farmacologia , Antivirais/química , Antivirais/metabolismo , Multimerização Proteica/efeitos dos fármacos
16.
N Engl J Med ; 384(6): 497-511, 2021 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-33264556

RESUMO

BACKGROUND: World Health Organization expert groups recommended mortality trials of four repurposed antiviral drugs - remdesivir, hydroxychloroquine, lopinavir, and interferon beta-1a - in patients hospitalized with coronavirus disease 2019 (Covid-19). METHODS: We randomly assigned inpatients with Covid-19 equally between one of the trial drug regimens that was locally available and open control (up to five options, four active and the local standard of care). The intention-to-treat primary analyses examined in-hospital mortality in the four pairwise comparisons of each trial drug and its control (drug available but patient assigned to the same care without that drug). Rate ratios for death were calculated with stratification according to age and status regarding mechanical ventilation at trial entry. RESULTS: At 405 hospitals in 30 countries, 11,330 adults underwent randomization; 2750 were assigned to receive remdesivir, 954 to hydroxychloroquine, 1411 to lopinavir (without interferon), 2063 to interferon (including 651 to interferon plus lopinavir), and 4088 to no trial drug. Adherence was 94 to 96% midway through treatment, with 2 to 6% crossover. In total, 1253 deaths were reported (median day of death, day 8; interquartile range, 4 to 14). The Kaplan-Meier 28-day mortality was 11.8% (39.0% if the patient was already receiving ventilation at randomization and 9.5% otherwise). Death occurred in 301 of 2743 patients receiving remdesivir and in 303 of 2708 receiving its control (rate ratio, 0.95; 95% confidence interval [CI], 0.81 to 1.11; P = 0.50), in 104 of 947 patients receiving hydroxychloroquine and in 84 of 906 receiving its control (rate ratio, 1.19; 95% CI, 0.89 to 1.59; P = 0.23), in 148 of 1399 patients receiving lopinavir and in 146 of 1372 receiving its control (rate ratio, 1.00; 95% CI, 0.79 to 1.25; P = 0.97), and in 243 of 2050 patients receiving interferon and in 216 of 2050 receiving its control (rate ratio, 1.16; 95% CI, 0.96 to 1.39; P = 0.11). No drug definitely reduced mortality, overall or in any subgroup, or reduced initiation of ventilation or hospitalization duration. CONCLUSIONS: These remdesivir, hydroxychloroquine, lopinavir, and interferon regimens had little or no effect on hospitalized patients with Covid-19, as indicated by overall mortality, initiation of ventilation, and duration of hospital stay. (Funded by the World Health Organization; ISRCTN Registry number, ISRCTN83971151; ClinicalTrials.gov number, NCT04315948.).


Assuntos
Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Antivirais/uso terapêutico , Tratamento Farmacológico da COVID-19 , Hidroxicloroquina/uso terapêutico , Interferon beta-1a/uso terapêutico , Lopinavir/uso terapêutico , Monofosfato de Adenosina/uso terapêutico , Idoso , Alanina/uso terapêutico , Antivirais/administração & dosagem , Antivirais/efeitos adversos , COVID-19/mortalidade , Quimioterapia Combinada , Feminino , Mortalidade Hospitalar , Hospitalização , Humanos , Análise de Intenção de Tratamento , Estimativa de Kaplan-Meier , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Respiração Artificial , Falha de Tratamento
17.
BMC Plant Biol ; 24(1): 624, 2024 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-38951758

RESUMO

Drought poses significant risks to maize cultivation by impairing plant growth, water uptake and yield; nano priming offers a promising avenue to mitigate these effects by enhancing plant water relations, stress tolerance and overall productivity. In the current experiment, we tested a hypothesis that seed priming with iron oxide nanoparticles (n-Fe2O3) can improve maize performance under water stress by improving its growth, water relations, yield and biochemical attributes. The experiment was conducted on a one main plot bisected into two subplots corresponding to the water and drought environments. Within each subplot, maize plants were raised from n-Fe2O3 primed seeds corresponding to 0 mg. L- 1 (as control treatment), 25, 50, 75, and 100 mg. L- 1 (as trial treatments). Seed priming with n-Fe2O3 at a concentration of 75 mg. L- 1 improved the leaf relative water content, water potential, photosynthetic water use efficiency, and leaf intrinsic water use efficiency of maize plants by 13%, 44%, 64% and 17%, respectively compared to control under drought stress. The same treatments improved plant biochemical attributes such as total chlorophyll content, total flavonoids and ascorbic acid by 37%, 22%, and 36%, respectively. Seed priming with n-Fe2O3 accelerated the functioning of antioxidant enzymes such as SOD and POD and depressed the levels of leaf malondialdehyde and hydrogen peroxide significantly. Seed priming with n-Fe2O3 at a concentration of 75 mg. L- 1 improved cob length, number of kernel rows per cob, and 100 kernel weight by 59%, 27% and 33%, respectively, under drought stress. Seed priming with n-Fe2O3 can be used to increase maize production under limited water scenarios.


Assuntos
Desidratação , Sementes , Água , Zea mays , Zea mays/efeitos dos fármacos , Zea mays/fisiologia , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Água/metabolismo , Secas , Fotossíntese/efeitos dos fármacos , Compostos Férricos , Clorofila/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/fisiologia
18.
Small ; : e2405399, 2024 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-39183523

RESUMO

The oxygen evolution reaction (OER) plays a pivotal role in diverse renewable energy storage and conversion technologies, including water electrolysis, electrochemical CO2 reduction, nitrogen fixation, and metal-air batteries. Among various water electrolysis techniques, proton exchange membrane (PEM)-based water electrolysis devices offer numerous advantages, including high current densities, exceptional chemical stability, excellent proton conductivity, and high-purity H2. Nevertheless, the prohibitive cost associated with Ir/Ru-based OER electrocatalysts poses a significant barrier to the broad-scale application of PEM-based water splitting. Consequently, it is crucial to advance the development of non-noble metal OER catalysis substance with high acid-activity and stability, thereby fostering their widespread integration into PEM water electrolyzers (PEMWEs). In this review, a comprehensive analysis of the acidic OER mechanism, encompassing the adsorbate evolution mechanism (AEM), lattice oxygen mechanism (LOM) and oxide path mechanism (OPM) is offered. Subsequently, a systematic summary of recently reported noble-metal-free catalysts including transition metal-based, carbon-based and other types of catalysts is provided. Additionally, a comprehensive compilation of in situ/operando characterization techniques is provided, serving as invaluable tools for furnishing experimental evidence to comprehend the catalytic mechanism. Finally, the present challenges and future research directions concerning precious-metal-free acidic OER are comprehensively summarized and discussed in this review.

19.
Small ; 20(12): e2306940, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38127968

RESUMO

The development of external stimuli-controlled payload systems has been sought after with increasing interest toward magnetothermally-triggered drug release (MTDR) carriers due to their non-invasive features. However, current MTDR carriers present several limitations, such as poor heating efficiency caused by the aggregation of iron oxide nanoparticles (IONPs) or the presence of antiferromagnetic phases which affect their efficiency. Herein, a novel MTDR carrier is developed using a controlled encapsulation method that fully fixes and confines IONPs of various sizes within the metal-organic frameworks (MOFs). This novel carrier preserves the MOF's morphology, porosity, and IONP segregation, while enhances heating efficiency through the oxidation of antiferromagnetic phases in IONPs during encapsulation. It also features a magnetothermally-responsive nanobrush that is stimulated by an alternating magnetic field to enable on-demand drug release. The novel carrier shows improved heating, which has potential applications as contrast agents and for combined chemo and magnetic hyperthermia therapy. It holds a great promise for magneto-thermally modulated drug dosing at tumor sites, making it an exciting avenue for cancer treatment.


Assuntos
Antineoplásicos , Hipertermia Induzida , Estruturas Metalorgânicas , Portadores de Fármacos , Campos Magnéticos
20.
Bioinformatics ; 39(4)2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36944259

RESUMO

SUMMARY: Data integration workflows for multiomics data take many forms across academia and industry. Efforts with limited resources often encountered in academia can easily fall short of data integration best practices for processing and combining high-content imaging, proteomics, metabolomics, and other omics data. We present Phenonaut, a Python software package designed to address the data workflow needs of migration, control, integration, and auditability in the application of literature and proprietary techniques for data source and structure agnostic workflow creation. AVAILABILITY AND IMPLEMENTATION: Source code: https://github.com/CarragherLab/phenonaut, Documentation: https://carragherlab.github.io/phenonaut, PyPI package: https://pypi.org/project/phenonaut/.


Assuntos
Metabolômica , Multiômica , Proteômica , Software , Fluxo de Trabalho
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA