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Although hexagonal boron nitride (h-BN) was initially considered a less promising photocatalyst due to its large band gap and apparent chemical inertness, its unique two-dimensional lamellar structure coupled with high stability and environmental friendliness, as the second largest van der Waals material after graphene, provides a unique platform for photocatalytic innovation. This review not only highlights the intrinsic qualities of h-BN with photocatalytic potentials, such as high stability, environmental compatibility, and tunable bandgap through various modification strategies but also provides a comprehensive overview of the recent advances in h-BN-based nanomaterials for environmental and energy applications, as well as an in-depth description of the modification methods and fundamental properties for these applications. In addition, we discuss the challenges and prospects of h-BN-based nanomaterials for future photocatalysis.
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Heterojunctions photocatalysts play a crucial role in achieving high solar-hydrogen conversion efficiency. In this work, we mainly focus on the charge transfer dynamics and pathways for sulfides-based Schottky junctions in the photocatalytic water splitting process to clarify the mechanism of heterostructures photocatalysis. Sulfides-based Schottky junctions (CdS/CoP and CdS/1T-MoS2) were successfully constructed for photocatalytic water splitting. Because of the higher work function of CdS than that of CoP and 1T-MoS2, the direction of the built-in electric field is from CoP or 1T-MoS2 to semiconductor. Therefore, CoP and 1T-MoS2 can act as electrons acceptors to accelerate the transfer of photo-generated electron on the surface of CdS, thus improving the charge utilization efficiency. Meanwhile, CoP and 1T-MoS2 as active sites can also promote the water dissociation and lower the H+ reduction overpotential, thus contributing to the excellent photocatalytic hydrogen production activity (23.59 mmol·h-1·g-1 and 1195.8 mol·h-1·g-1 for CdS/CoP and CdS/1T-MoS2).
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Photocatalysis represents a sustainable strategy for addressing energy shortages and global warming. The main challenges in the photocatalytic process include limited light absorption, rapid recombination of photo-induced carriers, and poor surface catalytic activity for reactant molecules. Defect engineering in photocatalysts has been proven to be an efficient approach for improving solar-to-chemical energy conversion. Sulfur vacancies can adjust the electron structure, act as electron reservoirs, and provide abundant adsorption and activate sites, leading to enhanced photocatalytic activity. In this work, we aim to elucidate the role of sulfur vacancies in photocatalytic reactions and provide valuable insights for engineering high-efficiency photocatalysts with abundant sulfur vacancies in the future. First, we delve into the fundamental understanding of photocatalysis. Subsequently, various strategies for fabricating sulfur vacancies in photocatalysts are summarized, along with the corresponding characterization techniques. More importantly, the enhanced photocatalytic mechanism, focusing on three key factors, including electron structure, charge transfer, and the surface catalytic reaction, is discussed in detail. Finally, the future opportunities and challenges in sulfur vacancy engineering for photocatalysis are identified.
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Aqueous zinc-ion hybrid supercapacitors (ZHSCs) with the characteristics of low cost, long cycle stability, and good safety have been regarded as potential candidates for wearable energy storage applications. Herein, we reasonably designed a unique binder-free nitrogen-doped (N-doped) porous carbon@TiO2@Ti multilayer core-sheath wire (N-CTNT), which has vertical N-doped carbon nanoholes radially aligned on the wire surface. The unique structure and nitrogen dopants of N-CTNTs have facilitated zinc deposition on N-CTNT to form a hierarchical and robust zinc-carbon composite (Zn@N-CTNTs). A wire-shaped ZHSC was constructed with N-CTNTs and Zn@N-CTNTs as cathode and anode electrodes, respectively. The as-prepared ZHSC has an outstanding specific capacitance of 488 mF cm-2 at 1 mA cm-2. This hybrid supercapacitor also exhibits an excellent energy density of 211 µW h cm-2, good rate performance, and long cycle stability with a capacity retention rate of 90.4% after 16,000 cycles.
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Ozone is a common air pollutant associated with various human diseases. The human ocular surface is frequently exposed to ozone in the troposphere, but the mechanisms by which ozone affects the ocular surface health remain unclear. This study aimed to establish a mouse model to investigate the effects of ozone exposure on the ocular surface and the corneal epithelium. The findings revealed that ozone exposure disrupted corneal epithelial homeostasis and differentiation, resulting in corneal squamous metaplasia. Further, ozone exposure induced oxidative damage and cytoplasmic leakage of mitochondrial DNA (mtDNA), thereby activating the cGAS/STING signaling pathway. The activation of the cGAS/STING signaling pathway triggered the activation of downstream NF-κB and TRAF6 signaling pathways, causing corneal inflammation, thereby promoting corneal inflammation and squamous metaplasia. Finally, C-176, a selective STING inhibitor, effectively prevented and treated corneal inflammation and squamous metaplasia caused by ozone exposure. This study revealed the role of mtDNA leakage-mediated cGAS/STING activation in corneal squamous epithelial metaplasia caused by ozone exposure. It also depicted the abnormal expression pattern of corneal epithelial keratin using three-dimensional images, providing new targets and strategies for preventing and treating corneal squamous metaplasia and other ocular surface diseases.
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Carcinoma de Células Escamosas , ADN Mitocondrial , Humanos , Animales , Ratones , Mitocondrias , Metaplasia , InflamaciónRESUMEN
PURPOSE: Meibomian glands (MGs) are crucial for maintaining tear film stability and ocular surface health. Here, we aim to establish a novel organotypic culture model of MGs and explore the risk factors of MG dysfunction (MGD). METHODS: We developed a novel organotypic culture model for MGs at the air-liquid interface. The viability and cell proliferation of MGs were assessed using CCK-8, immunofluorescence, and qPCR. Lipid accumulation was evaluated by Nile red staining and microscopic examination. Protein expression levels were evaluated by immunofluorescence and Western blot assay. EdU assay was employed to track the proliferation of acinar cells. The validity of the model was confirmed through culturing MGs from mice of different ages and incorporating certain drugs (Dex) into the culture system. RESULTS: Utilizing the novel culture model, the MG tissue exhibited sustained viability, cellular division, and continuous production of lipids for a duration of 7 days. Lipid droplets formed were directly visualized using light field microscopy. Through the cultivation of aged mice's MGs, it was discovered that aging resulted in diminished proliferation and lipid synthesis, along with an aberrant increase in Krt10 expression. Further application of this model showed that Dex treatment diminished MG's proliferation and lipid synthesis. Finally, an in vivo study was conducted to provide additional confirmation of the phenomenon of Dex-induced abnormalities. CONCLUSIONS: In this study, a stable organotypic culture model of the MGs was established. The organotypic culture model offers a valuable tool to investigate the pathophysiological mechanisms and facilitate drug screening for MG-related diseases.
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Disfunción de la Glándula de Meibomio , Glándulas Tarsales , Animales , Ratones , Glándulas Tarsales/metabolismo , Disfunción de la Glándula de Meibomio/metabolismo , Sistemas Microfisiológicos , Lágrimas/metabolismo , Factores de Riesgo , LípidosRESUMEN
BACKGROUND & AIMS: ß-Catenin, the effector molecule of the Wnt signaling pathway, has been shown to play a crucial role in bile acid homeostasis through direct inhibition of farnesoid X receptor (FXR), which has pleiotropic effects on bile acid homeostasis. We hypothesize that simultaneous suppression of ß-catenin signaling and activation of FXR in a mouse model of cholestasis will reduce injury and biliary fibrosis through inhibition of bile acid synthesis. METHODS: To induce cholestasis, we performed bile duct ligation (BDL) on wild-type male mice. Eight hours after surgery, mice received FXR agonists obeticholic acid, tropifexor, or GW-4064 or Wnt inhibitor Wnt-C59. Severity of cholestatic liver disease and expression of target genes were evaluated after either 5 days or 12 days of treatment. RESULTS: We found that although the FXR agonists worsened BDL-induced injury and necrosis after 5 days, Wnt-C59 did not. After 12 days of BDL, Wnt-C59 treatment, but not GW-4064 treatment, reduced both the number of infarcts and the number of inflammatory cells in liver. RNA sequencing analysis of whole livers revealed a notable suppression of nuclear factor kappa B signaling when Wnt signaling is inhibited. We then analyzed transcriptomic data to identify a cholangiocyte-specific signature in our model and demonstrated that Wnt-C59-treated livers were enriched for genes expressed in quiescent cholangiocytes, whereas genes expressed in activated cholangiocytes were enriched in BDL alone. A similar decrease in biliary injury and inflammation occurred in Mdr2 KO mice treated with Wnt-C59. CONCLUSIONS: Inhibiting Wnt signaling suppresses cholangiocyte activation and disrupts the nuclear factor kappa B-dependent inflammatory axis, reducing cholestatic-induced injury.
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Colestasis , Vía de Señalización Wnt , Masculino , Animales , Ratones , beta Catenina , FN-kappa B , Ácidos y Sales BiliaresRESUMEN
Brd4 has been intensively investigated as a promising drug target because of its implicated functions in oncogenesis, inflammation, and HIV-1 transcription. The formation of the Brd4-P-TEFb (CDK9/Cyclin T1) complex and its regulation of transcriptional elongation are critical for HIV latency reactivation and expression of many oncogenes. To further investigate the mechanism of the Brd4-P-TEFb complex in controlling elongation, mass spectrometry-based quantitative proteomics of the CDK9 interactome was performed. Upon treatment with the selective BET bromodomain inhibitor JQ1, 352 proteins were successfully identified with high confidence as CDK9-interacting proteins. Among them, increased bindings of HSP90 and CDC37 to CDK9 were particularly striking, and our data suggest that the HSP90-CDC37-P-TEFb complex is involved in controlling the dynamic equilibrium of the P-TEFb complex during BETi-induced reactivation of HIV-1 latency. Furthermore, the HSP90-CDC37-P-TEFb complex directly regulates HIV-1 transcription and relies on recruitment by heat shock factor 1 (HSF1) for binding to the HIV-1 promoter. These results advance the understanding of HSP90-CDC37-P-TEFb in HIV-1 latency reversal and enlighten the development of potential strategies to eradicate HIV-1 using a combination of targeted drugs.
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VIH-1 , Factores de Transcripción , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , VIH-1/genética , Factor B de Elongación Transcripcional Positiva/genética , Factor B de Elongación Transcripcional Positiva/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteómica , Chaperonas Moleculares/metabolismo , Proteínas HSP90 de Choque Térmico/metabolismo , Transcripción GenéticaRESUMEN
Corneal blindness is a worldwide major cause of vision loss, and corneal transplantation remains to be the most effective way to restore the vision. However, often there is a shortage of the donor corneas for transplantation. Therefore, it is urgent to develop a novel tissue-engineered corneal substitute. The present study envisaged the development of a novel and efficient method to prepare the corneal stromal equivalent from the marine biomaterials-squid. A chemical method was employed to decellularize the squid mantle scaffold to create a cell-free tissue substitute using 0.5% sodium dodecyl sulfate (SDS) solution. Subsequently, a novel clearing method, namely clear, unobstructed brain imaging cocktails (CUBIC) method was used to transparent it. Decellularized squid mantle scaffold (DSMS) has high decellularization efficiency, is rich in essential amino acids, and maintains the regular fiber alignment. In vitro experiments showed that the soaking solution of DSMS was non-toxic to human corneal epithelium cells. DSMS exhibited a good biocompatibility in the rat muscle by undergoing a complete degradation, and promoted the growth of the muscle. In addition, the DSMS showed a good compatibility with the corneal stroma in the rabbit inter-corneal implantation model, and promoted the regeneration of the corneal stroma without any evident rejection. Our results indicate that the squid mantle can be a potential new type of tissue-engineered corneal stroma material with a promising clinical application.
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Developing electrocatalysts with high energy conversion efficiency is urgently needed. In this work, P-Fe3O4/Fe@C electrodes with rich under-coordinated Fe atom interfaces are constructed for efficient pH-universal water splitting. The introduction of under-coordinated Fe atoms into the P-Fe3O4/Fe@C interface can increase the local charge density and polarize the 3d orbital lone electrons, which promotes water adsorption and activation to release more H*, thus elevating electrocatalytic activity. As a donor-like catalyst, P-Fe3O4/Fe@C displays excellent electrocatalytic performance with overpotentials of 160 mV and 214 mV in acidic and alkaline electrolytes at 10 mA cm-2, in addition to pH-universal long-term stability.
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Stable isotope chemical labeling methods have been widely used for high-throughput mass spectrometry (MS)-based quantitative proteomics in biological and clinical applications. However, the existing methods are far from meeting the requirements for high sensitivity detection. In the present study, a novel isobaric stable isotope N-phosphorylation labeling (iSIPL) strategy was developed for quantitative proteome analysis. The tryptic peptides were selectively labeled with iSIPL tag to generate the novel reporter ions containing phosphoramidate P-N bond with high intensities under lower collision energies. iSIPL strategy are suitable for peptide sequencing and quantitative analysis with high sensitivity and accuracy even for samples of limited quantity. Furthermore, iSIPL coupled with affinity purification and mass spectrometry was applied to measure the dynamics of cyclin dependent kinase 9 (CDK9) interactomes during transactivation of the HIV-1 provirus. The interaction of CDK9 with PARP13 was found to significantly decrease during Tat-induced activation of HIV-1 gene transcription, suggesting the effectiveness of iSIPL strategy in dynamic analysis of protein-protein interaction in vivo. More than that, the proposed iSIPL strategy would facilitate large-scale accurate quantitative proteomics by increasing multiplexing capability.
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Proteoma , Espectrometría de Masas en Tándem , Proteoma/análisis , Espectrometría de Masas en Tándem/métodos , Fosforilación , Péptidos/química , Marcaje Isotópico/métodos , IsótoposRESUMEN
Background: The COVID-19 pandemic has killed over 6 million people worldwide. Despite the accumulation of knowledge about the causative pathogen severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the pathogenesis of this disease, cures remain to be discovered. We searched for certain peptides that might interfere with spike protein (S protein)-angiotensin-converting enzyme 2 (ACE2) interactions. Methods: Phage display (PhD)-12 peptide library was screened against recombinant spike trimer (S-trimer) or receptor-binding domain (S-RBD) proteins. The resulting enriched peptide sequences were obtained, and their potential binding sites on S-trimer and S-RBD 3D structure models were searched. Synthetic peptides corresponding to these and other reference sequences were tested for their efficacy in blocking the binding of S-trimer protein onto recombinant ACE2 proteins or ACE2-overexpressing cells. Results: After three rounds of phage selections, two peptide sequences (C2, DHAQRYGAGHSG; C6, HWKAVNWLKPWT) were enriched by S-RBD, but only C2 was present in S-trimer selected phages. When the 3D structures of static monomeric S-RBD (6M17) and S-trimer (6ZGE, 6ZGG, 7CAI, and 7CAK, each with different status of S-RBDs in the three monomer S proteins) were scanned for potential binding sites of C2 and C6 peptides, C6 opt to bind the saddle of S-RBD in both 6M17 and erected S-RBD in S-trimers, but C2 failed to cluster there in the S-trimers. In the competitive S-trimer-ACE2-binding experiments, synthetic C2 and C6 peptides inhibited S-trimer binding onto 293T-ACE2hR cells at high concentrations (50 µM) but not at lower concentrations (10 µM and below), neither for the settings of S-trimer binding onto recombinant ACE2 proteins. Conclusion: Using PhD methodology, two peptides were generated bearing potentials to interfere with S protein-ACE2 interaction, which might be further exploited to produce peptidomimetics that block the attachment of SARS-CoV-2 virus onto host cells, hence diminishing the pathogenesis of COVID-19.
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Corneal bee sting (CBS) is one of the most common ocular traumas and can lead to blindness. The ophthalmic manifestations are caused by direct mechanical effects of bee stings, toxic effects, and host immune responses to bee venom (BV); however, the underlying pathogenesis remains unclear. Clinically, topical steroids and antibiotics are routinely used to treat CBS patients but the specific drug targets are unknown; therefore, it is imperative to study the pathological characteristics, injury mechanisms, and therapeutic targets involved in CBS. In the present study, a CBS injury model was successfully established by injecting BV into the corneal stroma of healthy C57BL/6 mice. F-actin staining revealed corneal endothelial cell damage, decreased density, skeletal disorder, and thickened corneal stromal. The terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) assay showed apoptosis of both epithelial and endothelial cells. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that cytokine-cytokine interactions were the most relevant pathway for pathogenesis. Protein-protein interaction (PPI) network analysis showed that IL-1, TNF, and IL-6 were the most relevant nodes. RNA-seq after the application of Tobradex® (0.3% tobramycin and 0.1% dexamethasone) eye ointment showed that Tobradex® not only downregulated relevant inflammatory factors but also reduced corneal pain as well as promoted nerve regeneration by repairing axons. Here, a stable and reliable model of CBS injury was successfully established for the first time, and the pathogenesis of CBS and the therapeutic targets of Tobradex® are discussed. These hub genes are expected to be biomarkers and therapeutic targets for the diagnosis and treatment of CBS.
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Venenos de Abeja , Lesiones de la Cornea , Mordeduras y Picaduras de Insectos , Animales , Venenos de Abeja/farmacología , Abejas/genética , Lesiones de la Cornea/diagnóstico , Lesiones de la Cornea/tratamiento farmacológico , Lesiones de la Cornea/genética , Citocinas , Modelos Animales de Enfermedad , Células Endoteliales , Ratones , Ratones Endogámicos C57BL , Combinación Dexametasona y Tobramicina , TranscriptomaRESUMEN
DNA damage shuts down genome-wide transcription to prevent transcriptional mutagenesis and to initiate repair signalling, but the mechanism to stall elongating RNA polymerase II (Pol II) is not fully understood. Central to the DNA damage response, poly(ADP-ribose) polymerase 1 (PARP1) initiates DNA repair by translocating to the lesions where it catalyses protein poly(ADP-ribosylation). Here we report that PARP1 inhibits Pol II elongation by inactivating the transcription elongation factor P-TEFb, a CDK9-cyclin T1 (CycT1) heterodimer. After sensing damage, the activated PARP1 binds to transcriptionally engaged P-TEFb and modifies CycT1 at multiple positions, including histidine residues that are rarely used as an acceptor site. This prevents CycT1 from undergoing liquid-liquid phase separation that is required for CDK9 to hyperphosphorylate Pol II and to stimulate elongation. Functionally, poly(ADP-ribosylation) of CycT1 promotes DNA repair and cell survival. Thus, the P-TEFb-PARP1 signalling plays a protective role in transcription quality control and genomic stability maintenance after DNA damage.
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Daño del ADN , Factor B de Elongación Transcripcional Positiva , ADP-Ribosilación , Ciclina T/química , Ciclina T/metabolismo , Factor B de Elongación Transcripcional Positiva/metabolismo , ARN Polimerasa II/genética , ARN Polimerasa II/metabolismoRESUMEN
Microplastics (MPs) have become a global concern as a key environmental pollutant. MPs are widely found in oceans, rivers, bottled water, plastic-packaged foods, and toiletries. The ocular surface is the exposed mucosal tissue, which comes in contact with MP particles contained in toiletries, tap water, cosmetics, and air. However, the effects of MPs on ocular surface health are still unclear. In this study, the toxic effects of polystyrene MPs (PS-MPs) on the ocular surface in vivo and in vitro were explored. The results demonstrated that 50 nm or 2 µm PS-MPs, following exposure for 48 h appeared in the cytoplasm of two kinds of eye cells in vitro and caused a concentration dependent reduction in cell viability, further causing oxidative stress and cell apoptosis. In addition, after treatment for 2 or 4 weeks, 50 nm and 2 µm PS-MPs were deposited in the conjunctival sac of mice. After 2 and 4 weeks of PS-MP treatment, the number of goblet cells in the lower eyelid conjunctival sac decreased to 65% and 40% of that in the control group, respectively. Moreover, dry eye like ocular surface damage and inflammation of conjunctiva and lacrimal gland in mice were observed. In conclusion, this study revealed that PS-MPs could cause ocular surface dysfunctions in mice, thus providing a new perspective for the toxic effects of MPs on ocular surface.
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Microplásticos , Contaminantes Químicos del Agua , Animales , Ratones , Microplásticos/toxicidad , Estrés Oxidativo , Plásticos/toxicidad , Poliestirenos/toxicidad , Contaminantes Químicos del Agua/toxicidadRESUMEN
With the large-scale application and high-speed operation of electronic equipment, the thermal diffusion problem presents an increasing requirement for effective heat dissipation materials. Herein, high thermal conductive graphite films were fabricated via the graphitization of polyimide (PI) films with different amounts of chemical catalytic reagent. The results showed that chemically imidized PI (CIPI) films exhibit a higher tensile strength, thermal stability, and imidization degree than that of purely thermally imidized PI (TIPI) films. The graphite films derived from CIPI films present a more complete crystal orientation and ordered arrangement. With only 0.72% chemical catalytic reagent, the graphitized CIPI film achieved a high thermal conductivity of 1767 W·m-1·K-1, which is much higher than that of graphited TIPI film (1331 W·m-1·K-1), with an increase of 32.8%. The high thermal conductivity is attributed to the large in-plane crystallite size and high crystal integrity. It is believed that the chemical imidization method prioritizes the preparation of high-quality PI films and helps graphite films achieve an excellent performance.
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A three-dimensional vertical-aligned graphene-polydopamine electrode (PDA@3DVAG) composite with vertical channels and conductive network is prepared by a method of unidirectional freezing and subsequent self-polymerization. When the prepared PDA@3DVAG is constructed as the positive electrode of zinc-ion hybrid supercapacitors (ZHSCs), excellent electrochemical performances are obtained. Compared with the conventional electrolyte, PDA@3DVAG composite electrode in highly concentrated salt electrolyte exhibits better multiplicity performance (48.92% at a current density of 3 A g-1), wider voltage window (-0.8~0.8 V), better cycle performance with specific capacitance from 96.7 to 59.8 F g-1, and higher energy density (46.14 Wh kg-1).
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The principal barrier for the eradication of HIV/AIDS is the virus latency. One of the effective strategies so called "shock and kill" is to use latency-reversing agents (LRAs) to activate the latent HIV reservoirs and then combine them with the highly active antiretroviral therapy (HAART) to eradicate the virus. However, most of the current LRAs are too toxic; therefore, they have not been used clinically. Our preliminary data indicated that polyphenols from grape seeds can activate HIV in latently infected Jurkat T cells. Owing to a lot of food containing polyphenols and based on a reasoning whether all of these kinds of polyphenols contain the latency-reversing function, in this study, we screened 22 fruits/vegetables to see whether polyphenols from these can reactivate latent HIV-1 transcription. We finally proved that the polyphenols from grape seeds, apple, pomegranate, and bilberry can reactivate latent HIV-1 transcription. The activation of which can be detected on the level of protein and mRNA. The activation of which is in a dose- and time-dependent manner, while the activated polyphenol extracts have the effects to stimulate Tat-independent HIV-1 transcription. The mechanism shows that polyphenol extracts from grape seeds and apple can stimulate P-TEFb's release from 7SK snRNP to induce HIV gene transcription. These results indicate that using a few food of high-content polyphenols as latent activators and combining HARRT may be of great use for the treatment of HIV/AIDS in the future.
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VIH-1/genética , Malus , Extractos Vegetales/farmacología , Polifenoles/farmacología , Factor B de Elongación Transcripcional Positiva/fisiología , Ribonucleoproteínas Nucleares Pequeñas , Semillas , Transcripción Viral/efectos de los fármacos , VitisRESUMEN
Three-dimensional vertically aligned graphene (3DVAG) was prepared by a unidirectional freezing method, and its electrochemical performances were evaluated as electrode materials for zinc-ion hybrid supercapacitors (ZHSCs). The prepared 3DVAG has a vertically ordered channel structure with a diameter of about 20-30 µm and a length stretching about hundreds of microns. Compared with the random structure of reduced graphene oxide (3DrGO), the vertical structure of 3DVAG in a three-electrode system showed higher specific capacitance, faster ion diffusion, and better rate performance. The specific capacitance of 3DVAG reached 66.6 F·g-1 and the rate performance reached 92.2%. The constructed 3DVAG zinc-ion hybrid supercapacitor also showed excellent electrochemical performance. It showed good capacitance retention up to 94.6% after 3000 cycles at the current density of 2 A·g-1.
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The BET-bromodomain protein BRD4 uses two bromodomains to target acetyl-histones and other domains to recruit P-TEFb and other transcription factors to stimulate transcription of proto-oncogenes and key cell identity genes. Recent studies show that its ability to form phase-separated condensates that cluster preferentially at the super-enhancer regions of target genes is key for BRD4 to exert its functions. Here, we describe the identification of a natural product called PCG from polygonum cuspidatum Sieb.et Zucc., a traditional Chinese medicinal herb, that directly binds to BRD4. This binding inhibits BRD4 phase separation, turns dynamic BRD4 nuclear condensates into static aggregates, and effectively shuts down transcription of BRD4-dependent genes. Thus, through PCG we have discovered a BET inhibitor that not only selectively targets BRD4 but also works by suppressing phase separation, a mechanism of action that is different from those of the other known BET inhibitors.