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1.
Nucleic Acids Res ; 50(4): 1829-1848, 2022 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-35166828

RESUMO

DNA G4-structures from human c-MYC promoter and telomere are considered as important drug targets; however, the developing of small-molecule-based fluorescent binding ligands that are highly selective in targeting these G4-structures over other types of nucleic acids is challenging. We herein report a new approach of designing small molecules based on a non-selective thiazole orange scaffold to provide two-directional and multi-site interactions with flanking residues and loops of the G4-motif for better selectivity. The ligands are designed to establish multi-site interactions in the G4-binding pocket. This structural feature may render the molecules higher selectivity toward c-MYC G4s than other structures. The ligand-G4 interaction studied with 1H NMR may suggest a stacking interaction with the terminal G-tetrad. Moreover, the intracellular co-localization study with BG4 and cellular competition experiments with BRACO-19 may suggest that the binding targets of the ligands in cells are most probably G4-structures. Furthermore, the ligands that either preferentially bind to c-MYC promoter or telomeric G4s are able to downregulate markedly the c-MYC and hTERT gene expression in MCF-7 cells, and induce senescence and DNA damage to cancer cells. The in vivo antitumor activity of the ligands in MCF-7 tumor-bearing mice is also demonstrated.


Assuntos
Antineoplásicos/química , Neoplasias da Mama , Quadruplex G , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Desenho de Fármacos , Feminino , Genes myc , Humanos , Ligantes , Células MCF-7 , Camundongos , Regiões Promotoras Genéticas , Telômero
2.
Angew Chem Int Ed Engl ; 63(5): e202314384, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38100253

RESUMO

Photocatalytic CO2 reduction into ideal hydrocarbon fuels, such as CH4 , is a sluggish kinetic process involving adsorption of multiple intermediates and multi-electron steps. Achieving high CH4 activity and selectivity therefore remains a great challenge, which largely depends on the efficiency of photogenerated charge separation and transfer as well as the intermediate energy levels in CO2 reduction. Herein, we construct La and Cu dual-atom anchored carbon nitride (LaCu/CN), with La-N4 and Cu-N3 coordination bonds connected by Cu-N-La bridges. The asymmetric Cu-N-La species enables the establishment of an atomic-level donor-acceptor structure, which allows the migration of electrons from La atoms to the reactive Cu atom sites. Simultaneously, intermediates during CO2 reduction on LaCu/CN demonstrate thermodynamically more favorable process for CH4 formation based on theoretical calculations. Eventually, LaCu/CN exhibits a high selectivity (91.6 %) for CH4 formation with a yield of 125.8 µmol g-1 , over ten times of that for pristine CN. This work presents a strategy for designing multi-functional dual-atom based photocatalysts.

3.
J Appl Microbiol ; 133(4): 2167-2181, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35490292

RESUMO

AIMS: The emerging of drug resistant Pseudomonas aeruginosa is a critical challenge and renders an urgent action to discover innovative antimicrobial interventions. One of these interventions is to disrupt the pseudomonas quinolone signal (pqs) quorum sensing (QS) system, which governs multiple virulence traits and biofilm formation. This study aimed to investigate the QS inhibitory activity of a series of new PqsR inhibitors bearing a quinoline scaffold against Ps. aeruginosa. METHODS AND RESULTS: The results showed that compound 1 suppressed the expression of QS-related genes and showed the best inhibitory activity to the pqs system of wild-type Ps. aeruginosa PAO1 with an IC50 of 20.22 µmol L-1 . The virulence factors including pyocyanin, total protease, elastase and rhamnolipid were significantly suppressed in a concentration-dependent manner with the compound. In addition, compound 1 in combination with tetracycline inhibited synergistically the bacterial growth and suppressed the biofilm formation of PAO1. The molecular docking studies also suggested that compound 1 could potentially interact with the ligand-binding domain of the Lys-R type transcriptional regulator PqsR as a competitive antagonist. CONCLUSIONS: The quinoline-based derivatives were found to interrupt the quorum sensing system via the pqs pathway and thus the production of virulence factors was inhibited and the antimicrobial susceptibility of Ps. aeruginosa was enhanced. SIGNIFICANCE AND IMPACT OF STUDY: The study showed that the quinoline-based derivatives could be used as an anti-virulence agent for treating Ps. aeruginosa infections.


Assuntos
Pseudomonas aeruginosa , Piocianina , Antibacterianos/química , Proteínas de Bactérias/metabolismo , Biofilmes , Endopeptidases/farmacologia , Ligantes , Simulação de Acoplamento Molecular , Elastase Pancreática/metabolismo , Pseudomonas aeruginosa/metabolismo , Piocianina/metabolismo , Percepção de Quorum , Tetraciclinas/farmacologia , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
4.
Biochem Biophys Res Commun ; 546: 40-45, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33561747

RESUMO

The emergence of worldwide spreading drug-resistant bacteria has been a serious threat to public health during the past decades. The development of new and effective antibacterial agents to address this critical issue is an urgent action. In the present study, we investigated the antibacterial activity of two 9,10-dihydroacridine derivatives and their mechanism. Both compounds were found possessing strong antibacterial activity against some selected Gram-positive bacteria including MRSA, VISA and VRE. The biological study suggests that the compounds promoted FtsZ polymerization and also disrupted Z-ring formation at the dividing site and consequently, the bacterial cell division is interrupted and causing cell death.


Assuntos
Acridinas/química , Acridinas/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Desenho de Fármacos , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Divisão Celular/efeitos dos fármacos , Proteínas do Citoesqueleto/antagonistas & inibidores , Proteínas do Citoesqueleto/química , Proteínas do Citoesqueleto/metabolismo , Bactérias Gram-Positivas/efeitos dos fármacos , Meticilina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos
5.
Microb Pathog ; 155: 104861, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33864878

RESUMO

The goal of the present study was to evaluate the fecal microbiome and serum metabolites in Xuebijing (XBJ)-injected rats after heat stroke using 16S rRNA gene sequencing and gas chromatography-mass spectrometry (GC-MS) metabolomics. Eighteen rats were divided into the control group (CON), heat stroke group (HS), and XBJ group. The 16S rRNA gene sequencing results revealed that the abundance of Bacteroidetes was overrepresented in the XBJ group compared to the HS group, while Actinobacteria was underrepresented. Metabolomic profiling showed that the pyrimidine metabolism pathway, pentose phosphate pathway, and glycerophospholipid metabolism pathway were upregulated in the XBJ group compared to the HS group. Taken together, these results demonstrated that heat stroke not only altered the gut microbiome community structure of rats but also greatly affected metabolic functions, leading to gut microbiome toxicity.


Assuntos
Medicamentos de Ervas Chinesas , Microbioma Gastrointestinal , Golpe de Calor , Animais , Metabolômica , RNA Ribossômico 16S/genética , Ratos
6.
BMC Cardiovasc Disord ; 21(1): 203, 2021 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-33882857

RESUMO

BACKGROUND: Catecholamine excess arising from pheochromocytomas and paragangliomas (PPGLs) can cause a wide spectrum of cardiac manifestations, including acute cardiac complications (ACCs) and subclinical myocardial injuries (SMIs). In this study, we aimed to conduct a comprehensive analysis of ACCs and SMIs in a large cohort of patients with PPGLs. METHODS: We retrospectively analyzed the clinical data of consecutive patients with PPGLs admitted between January 2013 and July 2020 (n = 189). The prevalence of ACCs and SMIs and characteristics of patients identified with ACCs and SMIs were investigated. Moreover, comparisons were performed between patients with and without ACCs. RESULTS: Fourteen patients (7.4%) fulfilled the criteria for ACCs, including nine (4.8%) who presented with Takotsubo-like cardiomyopathy, four (2.1%) with heart failure with preserved ejection fraction, and finally one (0.5%) with catecholamine-induced cardiomyopathy. Compared to those without ACCs (n = 175), patients with ACCs had a higher prevalence of epinephrine-producing PPGLs (81.8% vs 33.9%, P = 0.006) and were more likely to show invasive behavior (61.5% vs 27.3%, P = 0.022) or hemorrhage/necrosis (53.9% vs 17.4%, P = 0.005) on histology. The apical sparing pattern (5/7, 71.4%) was the dominant impairment pattern of longitudinal strain (LS) for patients displaying Takotsubo-like cardiomyopathy. In patients without cardiac symptoms, a fairly high proportion (21/77, 27.3%) of patients who underwent screening for troponin and/or natriuretic peptide and/or echocardiography had SMIs. CONCLUSIONS: One in every fourteen PPGL patients presented with ACCs, and in the patients with Takotsubo-like cardiomyopathy, the apical sparing pattern was the primary impairment pattern of LS. Additionally, nearly one-third of patients without symptoms had SMIs. The diagnosis of PPGLs should be considered in patients with acute reversible cardiomyopathy, especially in those exhibiting an apical sparing pattern of LS.


Assuntos
Neoplasias das Glândulas Suprarrenais/epidemiologia , Cardiopatias/epidemiologia , Paraganglioma/epidemiologia , Feocromocitoma/epidemiologia , Doença Aguda , Neoplasias das Glândulas Suprarrenais/diagnóstico , Adulto , China/epidemiologia , Feminino , Cardiopatias/diagnóstico , Cardiopatias/fisiopatologia , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Paraganglioma/diagnóstico , Feocromocitoma/diagnóstico , Prevalência , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Cardiomiopatia de Takotsubo/diagnóstico , Cardiomiopatia de Takotsubo/epidemiologia , Cardiomiopatia de Takotsubo/fisiopatologia , Fatores de Tempo
7.
J Med Virol ; 92(1): 71-77, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31471921

RESUMO

Gastric cancer (GC) is one of the infection-related cancers. Helicobacter pylori and Epstein-Barr virus (EBV) were established risk factors for GC. Recently, there are several reports showing the inconsistent association between hepatitis B virus (HBV) infection and the development of GC. To explore the relationship between HBV infection and the development of GC, we designed a meta-analysis of previous epidemiological studies, a hospital-based case-control study, followed by an immunohistochemistry (IHC) assay of HBV-exposed GC samples. We found that HBV infection was associated with an increased risk of GC based on the meta-analysis. No significant association between HBV infection and GC was detected according to our hospital-based case-control study. Histological examination showed that the gastric epithelium positive for HBx demonstrated a higher nuclear-cytoplasmic ratio compared to those HBx-negative cells. HBx and HBcAg were expressed more in tumors than those in normal counterparts in HBV-exposed subjects, and PD-L1 was lower in GC tissues from HBV carriers than those in HBV clearances. In conclusion, HBV infection may contribute to a higher risk for GC based on the meta-analysis and to the morphological atypia of gastric epithelium by the histological assessment, and GC patients among HBV carriers showed lower expression of PD-L1 may lose the chance for immune checkpoint blockade therapy.


Assuntos
Adenocarcinoma/virologia , Mucosa Gástrica/virologia , Hepatite B/complicações , Neoplasias Gástricas/virologia , Idoso , Antígeno B7-H1/genética , Estudos de Casos e Controles , Feminino , Mucosa Gástrica/patologia , Antígenos do Núcleo do Vírus da Hepatite B/genética , Vírus da Hepatite B/patogenicidade , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Transativadores/genética , Proteínas Virais Reguladoras e Acessórias/genética
8.
Langmuir ; 36(26): 7528-7532, 2020 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32513012

RESUMO

Metal-organic frameworks (MOFs) can provide atomically dispersed metal active coordination sites (M-NX, M-SX, and M-OX) for electrocatalytic reactions. Among them, MOFs with motif M-NX or analogues are expected to be promising active electrode materials for oxygen evolution reaction (OER). Contrary to bulk MOFs, two-dimensional (2D) MOFs usually have high surface areas, fully exposed active sites, and specific electrical properties. Herein, we constructed 2D Ni3(hexaiminotriphenylene)2 [Ni3(HITP)2] films on the electrode surface by utilizing the bottom-up liquid/liquid/gel tri-phase interface system and explored their potential applications in electrocatalytic OER. The thickness of the 2D Ni3(HITP)2 films can be controlled to be about 5 nm. The prepared 2D Ni3(HITP)2 films had oriented polycrystalline character and showed excellent performance in OER. A current density of 10 mA cm-2 for 3-layer Ni3(HITP)2 film electrodes was obtained at 1.62 V, which was 20 mV lower than that for the commercial IrO2 catalyst. Electrochemical tests and electrochemical impedance spectroscopy showed that better OER performance of 3-layer Ni3(HITP)2 films was ascribed to their high electrochemically active surface area, better kinetic process, and fast ion diffusion and transport.

9.
J Headache Pain ; 21(1): 14, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32046655

RESUMO

BACKGROUND: Galcanezumab is a novel monoclonal antibody that target to calcitonin gene-related peptide (CGRP). It has been tested for the preventive treatment of migraine and episodic cluster headache by multiple randomized clinical trials (RCTs) and have been found to reduce headache frequency. METHODS: We systematically searched PubMed and Embase on Cochrane Central Register of Controlled Trials (CENTRAL) from the earliest date to August 1, 2019. Relative risk (RR) and weighted mean difference (WMD) were used to evaluate clinical outcomes. RESULTS: Seven studies were pooled with 3889 patients. Subcutaneous injection of Galcanezumab at 120 mg, 240 mg leads to a statistically significant response rate for the treatment of migraine compared with placebo (120 mg: RR = 1.51; 95% CI, 1.33 to 1.70; P < 0.001; 240 mg: RR = 1.58; 95% CI, 1.43 to 1.76; P < 0.001). Among them, 120 mg group has the same treatment efficacy with 240 mg group (50% response: RR = 1.06; 95% CI, 0.92 to 1.22; P = 0.425; 75% response: RR = 1.07; 95% CI, 0.94 to 1.23; P = 0.301; 100% response; RR = 1.06; 95% CI, 0.81 to 1.37; P = 0.682; MHD: RR = - 0.08; 95% CI, - 0.55 to - 0.40; P = 0.748) while related to a lower risk for adverse events for the treatment of migraine (120 mg RR = 1.06; 95% CI, 0.99 to 1.14; P = 0.084; 240 mg: RR = 1.17; 95% CI, 1.09 to 1.25; P < 0.001). 300 mg per month galcanezumab is effective for the prevention of episodic cluster headache measured by at least 50% reduction of cluster headache frequency at week 3 (RR = 1.36; 95% CI, 1.00-1.84; P = 0.048). CONCLUSIONS: Use of galcanezumab is related to a significantly reduced monthly headache frequency compared with placebo for the treatment of migraine and episodic cluster headache, 120 mg has the same treatment efficacy with 240 mg group while related to a lower risk for adverse effects for the treatment of migraine. 300 mg per month galcanezumab is effective for the prevention of episodic cluster headache with no significantly increased adverse events.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Cefaleia Histamínica/tratamento farmacológico , Transtornos de Enxaqueca/tratamento farmacológico , Peptídeo Relacionado com Gene de Calcitonina , Método Duplo-Cego , Humanos , Injeções Subcutâneas , Avaliação de Resultados em Cuidados de Saúde , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento
10.
BMC Cancer ; 18(1): 259, 2018 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-29510676

RESUMO

BACKGROUND: Non-small-cell lung cancer (NSCLC) is characterized by abnormalities of numerous signaling proteins that play pivotal roles in cancer development and progression. Many of these proteins have been reported to be correlated with clinical outcomes of NSCLC. However, none of them could provide adequate accuracy of prognosis prediction in clinical application. METHODS: A total of 384 resected NSCLC specimens from two hospitals in Beijing (BJ) and Chongqing (CQ) were collected. Using immunohistochemistry (IHC) staining on stored formalin-fixed paraffin-embedded (FFPE) surgical samples, we examined the expression levels of 75 critical proteins on BJ samples. Random forest algorithm (RFA) and support vector machines (SVM) computation were applied to identify protein signatures on 2/3 randomly assigned BJ samples. The identified signatures were tested on the remaining BJ samples, and were further validated with CQ independent cohort. RESULTS: A 6-protein signature for adenocarcinoma (ADC) and a 5-protein signature for squamous cell carcinoma (SCC) were identified from training sets and tested in testing sets. In independent validation with CQ cohort, patients can also be divided into high- and low-risk groups with significantly different median overall survivals by Kaplan-Meier analysis, both in ADC (31 months vs. 87 months, HR 2.81; P <  0.001) and SCC patients (27 months vs. not reached, HR 9.97; P <  0.001). Cox regression analysis showed that both signatures are independent prognostic indicators and outperformed TNM staging (ADC: adjusted HR 3.07 vs. 2.43, SCC: adjusted HR 7.84 vs. 2.24). Particularly, we found that only the ADC patients in high-risk group significantly benefited from adjuvant chemotherapy (P = 0.018). CONCLUSIONS: Both ADC and SCC protein signatures could effectively stratify the prognosis of NSCLC patients, and may support patient selection for adjuvant chemotherapy.


Assuntos
Adenocarcinoma/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma de Células Escamosas/patologia , Neoplasias Pulmonares/patologia , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/metabolismo , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/metabolismo , Feminino , Seguimentos , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Transdução de Sinais , Taxa de Sobrevida , Análise Serial de Tecidos
11.
J Biol Chem ; 290(16): 10395-405, 2015 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-25681446

RESUMO

Excessive nuclear factor κB (NF-κB) activation should be precisely controlled as it contributes to multiple immune and inflammatory diseases. However, the negative regulatory mechanisms of NF-κB activation still need to be elucidated. Various types of polyubiquitin chains have proved to be involved in the process of NF-κB activation. Many negative regulators linked to ubiquitination, such as A20 and CYLD, inhibit IκB kinase activation in the NF-κB signaling pathway. To find new NF-κB signaling regulators linked to ubiquitination, we used a small scale siRNA library against 51 ubiquitin-associated domain-containing proteins and screened out UBXN1, which contained both ubiquitin-associated and ubiquitin regulatory X (UBX) domains as a negative regulator of TNFα-triggered NF-κB activation. Overexpression of UBXN1 inhibited TNFα-triggered NF-κB activation, although knockdown of UBXN1 had the opposite effect. UBX domain-containing proteins usually act as valosin-containing protein (VCP)/p97 cofactors. However, knockdown of VCP/p97 barely affected UBXN1-mediated NF-κB inhibition. At the same time, we found that UBXN1 interacted with cellular inhibitors of apoptosis proteins (cIAPs), E3 ubiquitin ligases of RIP1 in the TNFα receptor complex. UBXN1 competitively bound to cIAP1, blocked cIAP1 recruitment to TNFR1, and sequentially inhibited RIP1 polyubiquitination in response to TNFα. Therefore, our findings demonstrate that UBXN1 is an important negative regulator of the TNFα-triggered NF-κB signaling pathway by mediating cIAP recruitment independent of VCP/p97.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Regulação da Expressão Gênica , NF-kappa B/genética , Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adenosina Trifosfatases/antagonistas & inibidores , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Genes Reporter , Células HEK293 , Células HeLa , Humanos , Proteínas Inibidoras de Apoptose/genética , Proteínas Inibidoras de Apoptose/metabolismo , Luciferases/genética , Luciferases/metabolismo , NF-kappa B/antagonistas & inibidores , NF-kappa B/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Proteólise/efeitos dos fármacos , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral/genética , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Transdução de Sinais , Bibliotecas de Moléculas Pequenas , Fator de Necrose Tumoral alfa/farmacologia , Proteína com Valosina
12.
Phys Chem Chem Phys ; 19(1): 539-543, 2016 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-27910969

RESUMO

The introduction of intramolecular H-bonding by adding -OH functionalities adjacent to the Schiff base centers is considered to be a useful strategy to enhance the stability and crystallinity of bulk covalent organic frameworks (COFs). However, the influence of intramolecular H-bonding on the synthesis of surface COFs (SCOFs) have been barely explored. Herein, SCOFs based on the Schiff-base reaction between 1,3,5-tris(4-aminophenyl)benzene (TAPB) and terephthalaldehydes with symmetry or asymmetrically substituted hydroxyl functional groups are designed. In the absence of a solvent, hydroxyl substituents can be easily oxidized; thus argon protection is required to obtain high-quality SCOFs. Besides, an extended network with uniform pores can be achieved in spite of the symmetry of substituents. Both experimental results and theoretical calculations show that the influence of intramolecular hydrogen bonding on surface synthesis is not as important as that in bulk phase synthesis because the substrate itself can lead to the complanation of adsorbed molecules. The existence of intramolecular H-bonding can enhance the stability of the network in both acid and alkali environments.

13.
J Am Chem Soc ; 137(19): 6128-31, 2015 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-25948133

RESUMO

Halogen bonding has attracted much attention recently as an important driving force for supramolecular assembly and crystal engineering. Herein, we demonstrate for the first time the formation of a halogen bond-based open porous network on a graphite surface using ethynylpyridine and aryl-halide based building blocks. We found that the electrical stimuli of a scanning tunneling microscopy (STM) tip can induce the formation of a binary supramolecular structure on the basis of halogen bond formation between terminal pyridyl groups and perfluoro-iodobenzene. This electrical manipulation method can be applied to engineer a series of linear or porous structures by selecting halogen bond donor and acceptor fragments with different symmetries, as the directional interactions ultimately determine the structural outcome.

14.
J Chem Phys ; 142(10): 101905, 2015 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-25770494

RESUMO

The design and construction of molecular nanostructures with tunable topological structures are great challenges in molecular nanotechnology. Herein, we demonstrate the molecular engineering of Schiff-base bond connected molecular nanostructures. Building module construction has been adopted to modulate the symmetry of resulted one dimensional (1D) and two dimensional (2D) polymers. Specifically, we have designed and constructed 1D linear and zigzag polymers, 2D hexagonal and chessboard molecular nanostructures by varying the number of reactive sites and geometry and symmetry of precursors. It is demonstrated that high-quality conjugated polymers can be fabricated by using gas-solid interface reaction. The on-demanding synthesis of polymeric architectures with diverse topologies paves the way to fabricate molecular miniature devices with various desired functionalities.

15.
Small ; 10(23): 4934-9, 2014 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-25048172

RESUMO

With graphene-like topology and designable functional moieties, single-layered covalent organic frameworks (sCOFs) have attracted enormous interest for both fundamental research and application prospects. As the growth of sCOFs involves the assembly and reaction of precursors in a spatial defined manner, it is of great importance to understand the kinetics of sCOFs formation. Although several large families of sCOFs and bulk COF materials based on different coupling reactions have been reported, the synthesis of isomeric sCOFs by exchanging the coupling reaction moieties on precursors has been barely explored. Herein, a series of isomeric sCOFs based on Schiff-base reaction is designed to understand the effect of monomer structure on the growth kinetics of sCOFs. The distinctly different local packing motifs in the mixed assemblies for the two isomeric routes closely resemble to those in the assemblies of monomers, which affect the structural evolution process for highly ordered imine-linked sCOFs. In addition, surface diffusion of monomers and the molecule-substrate interaction, which is tunable by reaction temperature, also play an important role in structural evolutions. This study highlights the important roles of monomer structure and reaction temperature in the design and synthesis of covalent bond connected functional nanoporous networks.

16.
Langmuir ; 30(11): 3034-40, 2014 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-24628397

RESUMO

The ordered array of nanovoids in nanoporous networks, such as honeycomb, Kagome, and square, provides a molecular template for the accommodation of "guest molecules". Compared with the commonly studied guest molecules featuring high symmetry evenly incorporated into the template, guest molecules featuring lower symmetry are rare to report. Herein, we report the formation of a distinct patterned superlattice of guest molecules by selective trapping of guest molecules into the honeycomb network of trimesic acid (TMA). Two distinct surface patterns have been achieved by the guest inclusion induced adaptive reconstruction of a 2D molecular nanoporous network. The honeycomb networks can synergetically tune the arrangement upon inclusion of the guest molecules with different core size but similar peripherals groups, resulting in a trihexagonal Kagome or triangular patterns.

17.
Angew Chem Int Ed Engl ; 53(49): 13395-9, 2014 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-25376428

RESUMO

The construction of a spatially defined assembly of molecular building blocks, especially in the vertical direction, presents a great challenge for surface molecular engineering. Herein, we demonstrate that an electric field applied between an STM tip and a substrate triggered the formation of a bilayer structure at the solid-liquid interface. In contrast to the typical high electric-field strength (10(9)  V m(-1) ) used to induce structural transitions in supramolecular assemblies, a mild electric field (10(5)  V m(-1) ) triggered the formation of a bilayer structure of a polar molecule on top of a nanoporous network of trimesic acid on graphite. The bilayer structure was transformed into a monolayer kagome structure by changing the polarity of the electric field. This tailored formation and large-scale phase transformation of a molecular assembly in the perpendicular dimension by a mild electric field opens perspectives for the manipulation of surface molecular nanoarchitectures.

18.
Cell Biosci ; 14(1): 4, 2024 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-38178244

RESUMO

BACKGROUND: Recent advances in gene editing technology have opened up new avenues for in vivo gene therapy, which holds great promise as a potential treatment method for dilated cardiomyopathy (DCM). The CRISPR-Cas13 system has been shown to be an effective tool for knocking down RNA expression in mammalian cells. PspCas13b, a type VI-B effector that can be packed into adeno-associated viruses and improve RNA knockdown efficiency, is a potential treatment for diseases characterized by abnormal gene expression. RESULTS: Using PspCas13b, we were able to efficiently and specifically knockdown the mutant transcripts in the AC16 cell line carrying the heterozygous human TNNT2R141W (hTNNT2R141W) mutation. We used adeno-associated virus vector serotype 9 to deliver PspCas13b with specific single guide RNA into the hTNNT2R141W transgenic DCM mouse model, effectively knocking down hTNNT2R141W transcript expression. PspCas13b-mediated knockdown significantly increased myofilament sensitivity to Ca2+, improved cardiac function, and reduced myocardial fibrosis in hTNNT2R141W DCM mice. CONCLUSIONS: These findings suggest that targeting genes through Cas13b is a promising approach for in vivo gene therapy for genetic diseases caused by aberrant gene expression. Our study provides further evidence of Cas13b's application in genetic disease therapy and paves the way for future applicability of genetic therapies for cardiomyopathy.

19.
Carbohydr Polym ; 331: 121823, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38388030

RESUMO

Cellulose-based polymer scaffolds are highly diverse for designing and fabricating artificial bone substitutes. However, realizing the multi-biological functions of cellulose-based scaffolds has long been challenging. In this work, inspired by the structure and function of the extracellular matrix (ECM) of bone, we developed a novel yet feasible strategy to prepare ECM-like scaffolds with hybrid calcium/zinc mineralization. The 3D porous structure was formed via selective oxidation and freeze drying of bacterial cellulose. Following the principle of electrostatic interaction, calcium/zinc hybrid hydroxyapatite nucleated, crystallized, and precipitated on the 3D scaffold in simulated physiological conditions, which was well confirmed by morphology and composition analysis. Compared with alternative scaffold cohorts, this hybrid ion-loaded cellulose scaffold exhibited a pronounced elevation in alkaline phosphatase (ALP) activity, osteogenic gene expression, and cranial defect regeneration. Notably, the hybrid ion-loaded cellulose scaffold effectively fostered an M2 macrophage milieu and had a strong immune effect in vivo. In summary, this study developed a hybrid multifunctional cellulose-based scaffold that appropriately simulates the ECM to regulate immunomodulatory and osteogenic differentiation, setting a measure for artificial bone substitutes.


Assuntos
Substitutos Ósseos , Osteogênese , Osteogênese/genética , Cálcio/metabolismo , Alicerces Teciduais/química , Celulose/farmacologia , Celulose/metabolismo , Zinco/farmacologia , Regeneração Óssea , Durapatita/metabolismo , Matriz Extracelular/metabolismo
20.
J Am Chem Soc ; 135(28): 10470-4, 2013 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-23786481

RESUMO

Surface covalent organic frameworks (SCOFs), featured by atomic thick sheet with covalently bonded organic building units, are promised to possess unique properties associated with reduced dimensionality, well-defined in-plane structure, and tunable functionality. Although a great deal of effort has been made to obtain SCOFs with different linkages and building blocks via both "top-down" exfoliation and "bottom-up" surface synthesis approaches, the obtained SCOFs generally suffer a low crystallinity, which impedes the understanding of intrinsic properties of the materials. Herein, we demonstrate a self-limiting solid-vapor interface reaction strategy to fabricate highly ordered SCOFs. The coupling reaction is tailored to take place at the solid-vapor interface by introducing one precursor via vaporization to the surface preloaded with the other precursor. Following this strategy, highly ordered honeycomb SCOFs with imine linkage are obtained. The controlled formation of SCOFs in our study shows the possibility of a rational design and synthesis of SCOFs with desired functionality.


Assuntos
Grafite/química , Compostos Orgânicos/síntese química , Modelos Moleculares , Compostos Orgânicos/química , Teoria Quântica , Propriedades de Superfície , Termodinâmica , Volatilização
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