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1.
J Virol ; 98(1): e0155823, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38174926

RESUMO

Enterovirus A71 (EV-A71) can induce severe neurological complications and even fatal encephalitis in children, and it has caused several large outbreaks in Taiwan since 1998. We previously generated VP1 codon-deoptimized (VP1-CD) reverse genetics (rg) EV-A71 viruses (rgEV-A71s) that harbor a high-fidelity (HF) 3D polymerase. These VP1-CD-HF rgEV-A71s showed lower replication kinetics in vitro and decreased virulence in an Institute of Cancer Research (ICR) mouse model of EV-A71 infection, while still retaining their antigenicity in comparison to the wild-type virus. In this study, we aimed to further investigate the humoral and cellular immune responses elicited by VP1-CD-HF rgEV-A71s to assess the potential efficacy of these EV-A71 vaccine candidates. Following intraperitoneal (i.p.) injection of VP1-CD-HF rgEV-A71s in mice, we observed a robust induction of EV-A71-specific neutralizing IgG antibodies in the antisera after 21 days. Splenocytes isolated from VP1-CD-HF rgEV-A71s-immunized mice exhibited enhanced proliferative activities and cytokine production (IL-2, IFN-γ, IL-4, IL-6, and TNF-α) upon re-stimulation with VP1-CD-HF rgEV-A71, as compared to control mice treated with adjuvant only. Importantly, administration of antisera from VP1-CD-HF rgEV-A71s-immunized mice protected against lethal EV-A71 challenge in neonatal mice. These findings highlight that our generated VP1-CD-HF rgEV-A71 viruses are capable of inducing both cellular and humoral immune responses, supporting their potential as next-generation EV-A71 vaccines for combating EV-A71 infection.IMPORTANCEEV-A71 can cause severe neurological diseases and cause death in young children. Here, we report the development of synthetic rgEV-A71s with the combination of codon deoptimization and high-fidelity (HF) substitutions that generate genetically stable reverse genetics (rg) viruses as potential attenuated vaccine candidates. Our work provides insight into the development of low-virulence candidate vaccines through a series of viral genetic editing for maintaining antigenicity and genome stability and suggests a strategy for the development of an innovative next-generation vaccine against EV-A71.


Assuntos
Proteínas do Capsídeo , Enterovirus Humano A , Infecções por Enterovirus , RNA Polimerase Dependente de RNA , Animais , Camundongos , Anticorpos Antivirais/imunologia , Códon , Enterovirus Humano A/genética , Infecções por Enterovirus/imunologia , Vacinas Atenuadas , Proteínas do Capsídeo/genética , Imunidade Humoral , Imunidade Celular , Anticorpos Neutralizantes/imunologia , Vacinas Virais , Camundongos Endogâmicos ICR , Camundongos Endogâmicos BALB C , RNA Polimerase Dependente de RNA/genética
2.
Proc Natl Acad Sci U S A ; 119(49): e2210404119, 2022 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-36442095

RESUMO

Diapause is a form of dormancy used widely by insects to survive adverse seasons. Previous studies have demonstrated that forkhead box O (FoxO) is activated during pupal diapause initiation in the moth Helicoverpa armigera. However, it is unclear how FoxO induces diapause. Here, we show that knockout of FoxO causes H. armigera diapause-destined pupae to channel into nondiapause, indicating that FoxO is a master regulator that induces insect diapause. FoxO activates the ubiquitin-proteasome system (UPS) by promoting ubiquitin c (Ubc) expression via directly binding to the Ubc promoter. Activated UPS decreases transforming growth factor beta (TGFß) receptor signaling via ubiquitination to block developmental signaling to induce diapause. This study significantly advances the understanding of insect diapause by uncovering the detailed molecular mechanism of FoxO.


Assuntos
Diapausa de Inseto , Diapausa , Animais , Fator de Crescimento Transformador beta , Pupa , Transdução de Sinais , Receptores de Fatores de Crescimento Transformadores beta , Ubiquitina , Complexo de Endopeptidases do Proteassoma
3.
Proc Natl Acad Sci U S A ; 119(19): e2116380119, 2022 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-35500124

RESUMO

SignificanceThere is a common consensus that lode gold deposits mostly precipitated from metamorphic fluids via fluid boiling and/or fluid-rock interaction, but whether magmatic hydrothermal fluids and the mixing of such fluids with an external component have played a vital role in the formation of lode gold deposits remains elusive. We use garnet secondary ion mass spectrometry oxygen isotope analysis to demonstrate that the world-class Dongping lode gold deposit has been formed by multiple pulses of magmatic hydrothermal fluids and their mixing with large volumes of meteoric water. This study opens an opportunity to tightly constrain the origin of lode gold deposits worldwide and other hydrothermal systems that may have generated giant ore deposits in the Earth's crust.

4.
J Biol Chem ; 299(3): 102950, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36717080

RESUMO

Previous studies have demonstrated that high physiological levels of reactive oxygen species induce pupal diapause and extend lifespan in the moth Helicoverpa armigera. This has been shown to occur via protein arginine methyltransferase 1 (PRMT1) blockade of Akt-mediated phosphorylation of the transcription factor FoxO, after which activated FoxO promotes the initiation of diapause. However, it is unclear how PRMT1 is activated upstream of FoxO activity. Here, we show that high reactive oxygen species levels in the brains of H. armigera diapause-destined pupae activate the expression of c-Jun N-terminal kinase, which subsequently activates the transcription factor cAMP-response element binding protein. We show that cAMP-response element binding protein then directly binds to the PRMT1 promoter and upregulates its expression to prevent Akt-mediated FoxO phosphorylation and downstream FoxO nuclear localization. This novel finding that c-Jun N-terminal kinase promotes FoxO nuclear localization in a PRMT1-dependent manner to regulate pupal diapause reveals a complex regulatory mechanism in extending the healthspan of H. armigera.


Assuntos
Mariposas , Proteína-Arginina N-Metiltransferases , Animais , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Longevidade , Mariposas/fisiologia , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Pupa , Diapausa
5.
Biochem Biophys Res Commun ; 709: 149790, 2024 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-38564938

RESUMO

Macrophages play an important role in the development and progression of acute rejection after kidney transplantation. The study aims to investigate the biological role and significance of macrophage-associated genes (MAG) in acute rejection after kidney transplantation. We utilized transcriptome sequencing results from public databases related to acute rejection of kidney transplantation for comprehensive analysis and validation in animal experiments. We found that a large number of immune-related signaling pathways are activated in acute rejection. PPI protein interaction networks and machine learning were used to establish a Hub gene consisting of TYROBP and TLR8 for the diagnosis of acute rejection. The single-gene GSEA enrichment analysis and immune cell correlation analysis revealed a close correlation between the expression of Hub genes and immune-related biological pathways as well as the expression of multiple immune cells. In addition, the study of TF, miRNAs, and drugs provided a theoretical basis for regulating and treating the Hub genes in acute rejection. Finally, the animal experiments demonstrated once again that acute rejection can aggravate kidney tissue damage, apoptosis level, and increase the release of inflammatory factors. We established and validated a macrophage-associated diagnostic model for acute rejection after kidney transplantation, which can accurately diagnose the biological alterations in acute rejection after kidney transplantation.


Assuntos
Transplante de Rim , Animais , Transplante de Rim/efeitos adversos , Receptor 8 Toll-Like , Perfilação da Expressão Gênica , Biomarcadores , Macrófagos
6.
Small ; 20(36): e2401159, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38716681

RESUMO

Defects can introduce atomic structural modulation and tailor performance of materials. Herein, it demonstrates that semiconductor WO3 with inert electrocatalytic behavior can be activated through defect-induced tensile strains. Structural characterizations reveal that when simply treated in Ar/H2 atmosphere, oxygen vacancies will generate in WO3 and cause defective structures. Stacking faults are found in defects, thus modulating electronic structure and transforming electrocatalytic-inert WO3 into highly active electrocatalysts. Density functional theory (DFT) calculations are performed to calculate *H adsorption energies on various WOx surfaces, revealing the oxygen vacancy composition and strain predicted to optimize the catalytic activity of hydrogen evolution reaction (HER). Such defective tungsten oxides can be integrated into commercial proton exchange membrane (PEM) electrolyser with comparable performance toward Pt-based PEM. This work demonstrates defective metal oxides as promising non-noble metal catalysts for commercial PEM green-hydrogen generation.

7.
Small ; 20(9): e2306716, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37863816

RESUMO

The interaction between catalyst and support plays an important role in electrocatalytic hydrogen evolution (HER), which may explain the improvement in performance by phase transition or structural remodeling. However, the intrinsic behavior of these catalysts (dynamic evolution of the interface under bias, structural/morphological transformation, stability) has not been clearly monitored, while the operando technology does well in capturing the dynamic changes in the reaction process in real time to determine the actual active site. In this paper, nitrogen-doped molybdenum atom-clusters on Ti3 C2 TX (MoACs /N-Ti3 C2 TX ) is used as a model catalyst to reveal the dynamic evolution of MoAcs on Ti3 C2 TX during the HER process. Operando X-ray absorption structure (XAS) theoretical calculation and in situ Raman spectroscopy showed that the Mo cluster structure evolves to a 6-coordinated monatomic Mo structure under working conditions, exposing more active sites and thus improving the catalytic performance. It shows excellent HER performance comparable to that of commercial Pt/C, including an overpotential of 60 mV at 10 mA cm-2 , a small Tafel slope (56 mV dec-1 ), and high activity and durability. This study provides a unique perspective for investigating the evolution of species, interfacial migration mechanisms, and sources of activity-enhancing compounds in the process of electroreduction.

8.
Blood ; 139(3): 333-342, 2022 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-34665865

RESUMO

The study aimed to compare the efficacy and safety of all-trans retinoic acid (ATRA) plus low-dose rituximab (LD-RTX) with LD-RTX monotherapy in corticosteroid-resistant or relapsed immune thrombocytopenia (ITP) patients. Recruited patients were randomized at a ratio of 2:1 into 2 groups: 112 patients received LD-RTX plus ATRA, and 56 patients received LD-RTX monotherapy. Overall response (OR), defined as achieving a platelet count of ≥30 × 109/L confirmed on ≥2 separate occasions (≥7 days apart), at least a doubling of the baseline platelet count without any other ITP-specific treatment, and the absence of bleeding within 1 year after enrollment, was observed in more patients in the LD-RTX plus ATRA group (80%) than in the LD-RTX monotherapy group (59%) (between-group difference, 0.22; 95% CI, 0.07-0.36). Sustained response (SR), defined as maintenance of a platelet count >30 × 109/L, an absence of bleeding, and no requirement for any other ITP-specific treatment for 6 consecutive months after achievement of OR during 1 year following enrollment, was achieved by 68 (61%) patients in the combination group and 23 (41%) patients in the monotherapy group (between-group difference, 0.20; 95% CI, 0.04-0.35). The 2 most common adverse events (AEs) for the combination group were dry skin and headache or dizziness. Our findings demonstrated that ATRA plus LD-RTX significantly increased the overall and sustained response, indicating a promising treatment option for corticosteroid-resistant or relapsed adult ITP. This study is registered at www.clinicaltrials.gov as #NCT03304288.


Assuntos
Antineoplásicos/uso terapêutico , Fatores Imunológicos/uso terapêutico , Púrpura Trombocitopênica Idiopática/tratamento farmacológico , Rituximab/uso terapêutico , Tretinoína/uso terapêutico , Corticosteroides/uso terapêutico , Adulto , Antineoplásicos/administração & dosagem , Resistência a Medicamentos , Quimioterapia Combinada , Feminino , Humanos , Fatores Imunológicos/administração & dosagem , Masculino , Pessoa de Meia-Idade , Recidiva , Rituximab/administração & dosagem , Prevenção Secundária , Tretinoína/administração & dosagem
9.
BMC Cancer ; 24(1): 1327, 2024 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-39472811

RESUMO

Loss of ARID1A has been reported to drive the progression of lung adenocarcinoma, yet the underlying mechanism remains elusive. In this study, we performed secretome analysis to identify the key secreted proteins regulating lung adenocarcinoma progression. We showed that the VASN level was significantly elevated in the conditioned medium from ARID1A-depleted A549 and H1299 cells. Restoration of ARID1A in ARID1A-depleted lung adenocarcinoma cells prevented the upregulation and secretion of VASN. Clinical analysis demonstrated a negative correlation between ARID1A and VASN expression in ARID1A-mutated lung adenocarcinomas. The patients with ARID1A-mutated lung adenocarcinoma had significantly higher concentrations of serum VASN than healthy controls. Moreover, serum VASN concentrations were associated with TNM stage, lymph node metastasis, and overall survival of the patients with ARID1A-mutated lung adenocarcinoma. Functional studies indicated that VASN overexpression potentiated the proliferation, invasion, and tumorigenesis of lung adenocarcinoma cells. Antibody neutralization of VASN suppressed the aggressiveness of ARID1A-depleted lung adenocarcinoma cells both in vitro and in vivo. Addition of recombinant VASN protein promoted the proliferation and invasion of lung adenocarcinoma cells. Additionally, knockdown of Notch1 blocked the aggressive phenotype induced by recombinant VASN protein. In conclusion, our data uncover the role of VASN in mediating the progression of ARID1A-depleted lung adenocarcinoma and highlight VASN as a promising therapeutic target for this disease.


Assuntos
Adenocarcinoma de Pulmão , Proteínas de Ligação a DNA , Neoplasias Pulmonares , Fatores de Transcrição , Humanos , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/patologia , Adenocarcinoma de Pulmão/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Camundongos , Animais , Proliferação de Células , Fenótipo , Masculino , Feminino , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Mutação , Células A549 , Pessoa de Meia-Idade , Invasividade Neoplásica , Progressão da Doença
10.
Cell Commun Signal ; 22(1): 389, 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39103830

RESUMO

Modern human society is burdened with the pandemic of cardiovascular and metabolic diseases. Metrnl is a widely distributed secreted protein in the body, involved in regulating glucose and lipid metabolism and maintaining cardiovascular system homeostasis. In this review, we present the predictive and therapeutic roles of Metrnl in various cardiovascular and metabolic diseases, including atherosclerosis, ischemic heart disease, cardiac remodeling, heart failure, hypertension, chemotherapy-induced myocardial injury, diabetes mellitus, and obesity.


Assuntos
Biomarcadores , Doenças Cardiovasculares , Doenças Metabólicas , Humanos , Doenças Metabólicas/metabolismo , Doenças Metabólicas/tratamento farmacológico , Doenças Cardiovasculares/metabolismo , Biomarcadores/metabolismo , Animais
11.
J Org Chem ; 89(4): 2448-2458, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38275288

RESUMO

An operationally simple and green protocol using a NiSO4·6H2O/cationic 2,2'-bipyridyl ligand system as a water-soluble catalyst for the coupling of arylboronic acids with (2-haloallyl)phosphonates and (2-haloallyl)sulfones in water under air was developed. The reaction was performed at 120 °C with arylboronic acids (2 mmol) and (2-haloallyl)phosphonates or sulfones (1 mmol) in the presence of 5 mol % of the Ni catalytic system in a basic aqueous solution for 1 h, giving the corresponding 2-aryl allyl phosphonates or sulfones in good to excellent yields. This reaction features the use of an abundant transition metal as a catalyst in water and exhibits high functional group tolerance, rendering it an eco-friendly procedure.

12.
J Org Chem ; 89(11): 7770-7779, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38738957

RESUMO

A visible-light-enabled photoredox radical cascade cyclization of 2-vinyl benzimidazole derivatives is developed. This chemistry is applicable to a wide range of N-aroyl 2-vinyl benzimidazoles as acceptors, and halo compounds, including alkyl halides, acyl chlorides and sulfonyl chlorides, as radical precursors. The Langlois reagent also serves as an effective partner in this photocatalytic oxidative cascade process. This protocol provides a robust alternative for rendering highly functionalized benzo[4,5]imidazo[1,2-b]isoquinolin-11(6H)-ones.

13.
Org Biomol Chem ; 22(37): 7612-7617, 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39206527

RESUMO

A highly effective and enantioselective vinylogous Mannich reaction between benzothiazolimines and γ-butenolides catalyzed by a quinine based squaramide has been disclosed. A series of chiral benzothiazole amines containing a γ,γ-disubstituted butanolide scaffold bearing an adjacent chiral stereocenter have been successfully obtained in good to excellent yields (up to 91%) with excellent enantioselectivities (up to >99% ee) and diastereoselectivities (>20 : 1 dr) with broad substrate generality under mild conditions. The new scaffold integrated with both chiral benzothiazolimine and γ-butenolide moieties may provide a possibility for the development of new pharmaceutical entities.

14.
Environ Sci Technol ; 58(16): 7087-7098, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38651173

RESUMO

Aerobic anoxygenic phototrophic bacteria (AAPB) contribute profoundly to the global carbon cycle. However, most AAPB in marine environments are uncultured and at low abundance, hampering the recognition of their functions and molecular mechanisms. In this study, we developed a new culture-independent method to identify and sort AAPB using single-cell Raman/fluorescence spectroscopy. Characteristic Raman and fluorescent bands specific to bacteriochlorophyll a (Bchl a) in AAPB were determined by comparing multiple known AAPB with non-AAPB isolates. Using these spectroscopic biomarkers, AAPB in coastal seawater, pelagic seawater, and hydrothermal sediment samples were screened, sorted, and sequenced. 16S rRNA gene analysis and functional gene annotations of sorted cells revealed novel AAPB members and functional genes, including one species belonging to the genus Sphingomonas, two genera affiliated to classes Betaproteobacteria and Gammaproteobacteria, and function genes bchCDIX, pucC2, and pufL related to Bchl a biosynthesis and photosynthetic reaction center assembly. Metagenome-assembled genomes (MAGs) of sorted cells from pelagic seawater and deep-sea hydrothermal sediment belonged to Erythrobacter sanguineus that was considered as an AAPB and genus Sphingomonas, respectively. Moreover, multiple photosynthesis-related genes were annotated in both MAGs, and comparative genomic analysis revealed several exclusive genes involved in amino acid and inorganic ion metabolism and transport. This study employed a new single-cell spectroscopy method to detect AAPB, not only broadening the taxonomic and genetic contents of AAPB in marine environments but also revealing their genetic mechanisms at the single-genomic level.


Assuntos
Metagenômica , Água do Mar , Metagenômica/métodos , Água do Mar/microbiologia , RNA Ribossômico 16S/genética , Análise Espectral Raman , Filogenia , Análise de Célula Única
15.
Environ Sci Technol ; 58(11): 5024-5034, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38454313

RESUMO

Detecting cyanobacteria in environments is an important concern due to their crucial roles in ecosystems, and they can form blooms with the potential to harm humans and nonhuman entities. However, the most widely used methods for high-throughput detection of environmental cyanobacteria, such as 16S rRNA sequencing, typically provide above-species-level resolution, thereby disregarding intraspecific variation. To address this, we developed a novel DNA microarray tool, termed the CyanoStrainChip, that enables strain-level comprehensive profiling of environmental cyanobacteria. The CyanoStrainChip was designed to target 1277 strains; nearly all major groups of cyanobacteria are included by implementing 43,666 genome-wide, strain-specific probes. It demonstrated strong specificity by in vitro mock community experiments. The high correlation (Pearson's R > 0.97) between probe fluorescence intensities and the corresponding DNA amounts (ranging from 1-100 ng) indicated excellent quantitative capability. Consistent cyanobacterial profiles of field samples were observed by both the CyanoStrainChip and next-generation sequencing methods. Furthermore, CyanoStrainChip analysis of surface water samples in Lake Chaohu uncovered a high intraspecific variation of abundance change within the genus Microcystis between different severity levels of cyanobacterial blooms, highlighting two toxic Microcystis strains that are of critical concern for Lake Chaohu harmful blooms suppression. Overall, these results suggest a potential for CyanoStrainChip as a valuable tool for cyanobacterial ecological research and harmful bloom monitoring to supplement existing techniques.


Assuntos
Cianobactérias , Microcystis , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , RNA Ribossômico 16S/genética , Ecossistema , Proliferação Nociva de Algas , Cianobactérias/genética , Lagos/microbiologia , Microcystis/genética
16.
BMC Vet Res ; 20(1): 458, 2024 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-39390513

RESUMO

BACKGROUND: Gut microbial composition and its metabolites are crucial for livestock production performance. Metabolite profiles from autopsied biospecimens provide vital information on the basic mechanisms that affect the overall health and production traits in livestock animals. However, the role of the host breed in the gut microbiome and fecal metabolome of commercial pigs remains unclear. In this work, differences in microbiota composition among three commercial pig breeds Duroc, Yorkshire, and Landrace were measured by 16S rRNA gene sequencing. Fecal metabolite compositions of the three pig breeds were detected using untargeted metabolomics. RESULTS: There were significant differences in the gut microbiomes of the three species, indicating that host breed affects the diversity and structure of gut microbiota. Several breed-associated microorganisms were identified at different taxonomic levels. Notely, most microbial taxa were annotated as Lactobacillacea, Muribaculaceae, and Oscillospiraceae. Several bacteria, including Lactobacillus, Subdoligranulum, Faecalibacterium, Oscillospira, Oscillospiraceae_UCG-002, and Christensenellaceae_R-7_group, could be considered as biomarkers for improving the backfat thickness (BF) for commercial pigs. Additionally, KEGG analysis of gut microbiota further revealed that arginine biosynthesis, pyruvate metabolism, and fatty acid biosynthesis varied greatly among pig breeds. Multiple gut bacterial metabolites (e.g., spermidine, estradiol, and palmitic acid) were identified as breed-associated. Mediation analysis ultimately revealed the cross-talk among gut microbiota, metabolites, and BF thickness, proclaiming that the microbial and metabolic biomarkers identified in this study could be used as biomarkers for improving BF phenotype. CONCLUSIONS: This work provides vital insights into breed effects on gut microbiota and metabolite compositions of commercial pigs and uncovers potential biomarkers that are significant for pig breed improvement.


Assuntos
Fezes , Microbioma Gastrointestinal , Metaboloma , RNA Ribossômico 16S , Animais , Fezes/microbiologia , RNA Ribossômico 16S/genética , Suínos , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Bactérias/isolamento & purificação , Sus scrofa
17.
J Chem Phys ; 160(4)2024 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-38265089

RESUMO

We utilized molecular dynamic simulation to investigate the glass formation of star polymer melts in which the topological complexity is varied by altering the number of star arms (f). Emphasis was placed on how the "confinement effect" of repulsive inter-arm interactions within star polymers influences the thermodynamics and dynamics of star polymer melts. All the characteristic temperatures of glass formation were found to progressively increase with increasing f, but unexpectedly the fragility parameter KVFT was found to decrease with increasing f. As previously observed, stars having more than 5 or 6 arms adopt an average particle-like structure that is more contracted relative to the linear polymer size having the same mass and exhibit a strong tendency for intermolecular and intramolecular segregation. We systematically analyzed how varying f alters collective particle motion, dynamic heterogeneity, the decoupling exponent ζ phenomenologically linking the slow ß- and α-relaxation times, and the thermodynamic scaling index γt. Consistent with our hypothesis that the segmental dynamics of many-arm star melts and thin supported polymer films should exhibit similar trends arising from the common feature of high local segmental confinement, we found that ζ increases considerably with increasing f, as found in supported polymer films with decreasing thickness. Furthermore, increasing f led to greatly enhanced elastic heterogeneity, and this phenomenon correlates strongly with changes in ζ and γt. Our observations should be helpful in building a more rational theoretical framework for understanding how molecular topology and geometrical confinement influence the dynamics of glass-forming materials more broadly.

18.
J Chem Phys ; 160(6)2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38341796

RESUMO

We study the dynamics of the end monomers of a real chain confined in a spherical cavity to search for a small target on the cavity surface using Langevin dynamics simulation. The results are compared and contrasted with those of a Rouse chain to understand the influence of excluded volume interactions on the search dynamics, as characterized by the first passage time (FPT). We analyze how the mean FPT depends on the cavity size Rb, the target size a, and the degree of confinement quantified by Rg/Rb, with Rg being the polymer radius of gyration in free space. As a basic finding, the equilibrium distribution of the end monomers of a real chain in a closed spherical cavity differs from that of a Rouse chain at a given Rg/Rb, which leads to the differences between the mean FPTs of real and Rouse chains. Fitting the survival probability S(t) by a multi-exponential form, we show that the S(t) of real chains exhibits multiple characteristic times at large Rg/Rb. Our simulation results indicate that the search dynamics of a real chain exhibit three characteristic regimes as a function of Rg/Rb, including the transition from the Markovian to non-Markovian process at Rg/Rb ≈ 0.39, along with two distinct regimes at 0.39 < Rg/Rb < 1.0 and Rg/Rb > 1.0, respectively, where S(t) exhibits a single characteristic time and multiple characteristic times.

19.
Cell Mol Biol Lett ; 29(1): 62, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38684954

RESUMO

BACKGROUND: Enhancing angiogenesis may be an effective strategy to promote functional recovery after ischemic stroke. Inflammation regulates angiogenesis. Microglia are crucial cells that initiate inflammatory responses after various brain injuries. Long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) plays a role in regulating brain injury. This study aimed to explore the effects of NEAT1-regulated microglial polarization on the neovascularization capacity of cerebrovascular endothelial cells and the underlying molecular regulatory mechanisms. METHODS: Mouse cerebral arterial endothelial cells (mCAECs) were co-cultured with BV-2 cells in different groups using a Transwell system. NEAT1 expression levels were measured by fluorescence quantitative reverse transcription PCR. Levels of IL-1ß, IL-6, TNF-α, Arg-1, IL-4, and IL-10 were determined using ELISA. Expression levels of CD86 and CD163 were detected by immunofluorescence. The neovascularization capacity of mCAECs was assessed using CCK-8, Transwell, Transwell-matrigel, and tube formation assays. Label-free quantification proteomics was carried out to identify differentially expressed proteins. Protein levels were measured by Western blotting. RESULTS: NEAT1 overexpression induced M1 polarization in BV-2 cells, whereas NEAT1 knockdown blocked lipopolysaccharide-induced M1 polarization in microglia. NEAT1-overexpressing BV-2 cells suppressed the angiogenic ability of mCAECs, and NEAT1-knocking BV-2 cells promoted the angiogenic ability of mCAECs under lipopolysaccharide treatment. Label-free quantitative proteomic analysis identified 144 upregulated and 131 downregulated proteins that were induced by NEAT1 overexpression. The AMP-activated protein kinase (AMPK) signaling pathway was enriched in the Kyoto Encyclopedia of Genes and Genomes analysis of the differentially expressed proteins. Further verification showed that NEAT1 inactivated the AMPK signaling pathway. Moreover, the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide reversed the effect of NEAT1 on BV-2 polarization and the regulatory effect of NEAT1-overexpressing BV-2 cells on the angiogenic ability of mCAECs. CONCLUSIONS: NEAT1 inhibits the angiogenic activity of mCAECs by inducing M1 polarization of BV-2 cells through the AMPK signaling pathway. This study further clarified the impact and mechanism of NEAT1 on microglia and the angiogenic ability of cerebrovascular endothelial cells.


Assuntos
Proteínas Quinases Ativadas por AMP , Células Endoteliais , Microglia , RNA Longo não Codificante , Transdução de Sinais , Animais , Microglia/metabolismo , Microglia/efeitos dos fármacos , Camundongos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Células Endoteliais/metabolismo , Células Endoteliais/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Artérias Cerebrais/metabolismo , Artérias Cerebrais/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Neovascularização Fisiológica/genética , Linhagem Celular , Polaridade Celular/efeitos dos fármacos
20.
BMC Med Imaging ; 24(1): 39, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38336622

RESUMO

BACKGROUND: Coronary computed tomography angiography stenosis score (CCTA-SS) is a proposed diagnosis score that considers the plaque characteristics, myocardial function, and the diameter reduction rate of the lesions. This study aimed to evaluate the diagnostic performance of the CCTA-SS in seeking coronary artery disease (CAD). METHODS: The 228 patients with suspected CAD who underwent CCTA and invasive coronary angiography (ICA) procedures were under examination. The diagnostic performance was evaluated with the receiver operating curve (ROC) for CCTA-SS in detecting CAD (defined as a diameter reduction of ≥ 50%) and severe CAD (defined as a diameter reduction of ≥ 70%). RESULTS: The area under ROC (AUC) of CCTA-SS was 0.909 (95% CI: 0.864-0.943), which was significantly higher than that of CCTA (AUC: 0.826; 95% CI: 0.771-0.873; P = 0.0352) in diagnosing of CAD with a threshold of 50%. The optimal cutoff point of CCTA-SS was 51% with a sensitivity of 90.66%, specificity of 95.65%, positive predictive value of 98.80%, negative predictive value of 72.13%, and accuracy of 91.67%, whereas the optimal cutoff point of CCTA was 55%, and the corresponding values were 87.36%, 93.48%, 98.15%, 65.15%, and 88.60%, respectively. With a threshold of 70%, the performance of CCTA-SS with an AUC of 0.927 (95% CI: 0.885-0.957) was significantly higher than that of CCTA with an AUC of 0.521 (95% CI: 0.454-0.587) (P < 0.0001). CONCLUSIONS: CCTA-SS significantly improved the diagnostic accuracy of coronary stenosis, including CAD and severe CAD, compared with CCTA.


Assuntos
Doença da Artéria Coronariana , Estenose Coronária , Humanos , Angiografia por Tomografia Computadorizada/métodos , Constrição Patológica , Estenose Coronária/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Angiografia Coronária/métodos , Valor Preditivo dos Testes
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