RESUMO
The generation of highly diverse antigen receptors in T and B lymphocytes relies on V(D)J recombination. The enhancer Eα has been implicated in regulating the accessibility of Vα and Jα genes through long-range interactions during rearrangements of the T-cell antigen receptor gene Tcra. However, direct evidence for Eα physically mediating the interaction of Vα and Jα genes is still lacking. In this study, we utilized the 3C-HTGTS assay, a chromatin interaction technique based on 3C, to analyze the higher order chromatin structure of the Tcra locus. Our analysis revealed the presence of sufficient information in the 3C-HTGTS data to detect multiway contacts. Three-way contact analysis of the Tcra locus demonstrated the co-occurrence of the proximal Jα genes, Vα genes and Eα in CD4+CD8+ double-positive thymocytes. Notably, the INT2-TEAp loop emerged as a prominent structure likely to be responsible for bringing the proximal Jα genes and the Vα genes into proximity. Moreover, the enhancer Eα utilizes this loop to establish physical proximity with the proximal Vα gene region. This study provides insights into the higher order chromatin structure of the Tcra locus, shedding light on the spatial organization of chromatin and its impact on V(D)J recombination.
Assuntos
Receptores de Antígenos de Linfócitos T alfa-beta , Timócitos , Cromatina/genética , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Recombinação V(D)J/genética , Animais , CamundongosRESUMO
Protein-DNA damage interactions are critical for understanding the mechanism of DNA repair and damage response. However, due to the relatively random distributions of UV-induced damage and other DNA bulky adducts, it is challenging to measure the interactions between proteins and these lesions across the genome. To address this issue, we developed a new method named Protein-Associated DNA Damage Sequencing (PADD-seq) that uses Damage-seq to detect damage distribution in chromatin immunoprecipitation-enriched DNA fragments. It is possible to delineate genome-wide protein-DNA damage interactions at base resolution with this strategy. Using PADD-seq, we observed that RNA polymerase II (Pol II) was blocked by UV-induced damage on template strands, and the interaction declined within 2 h in transcription-coupled repair-proficient cells. On the other hand, Pol II was clearly restrained at damage sites in the absence of the transcription-repair coupling factor CSB during the same time course. Furthermore, we used PADD-seq to examine local changes in H3 acetylation at lysine 9 (H3K9ac) around cisplatin-induced damage, demonstrating the method's broad utility. In conclusion, this new method provides a powerful tool for monitoring the dynamics of protein-DNA damage interaction at the genomic level, and it encourages comprehensive research into DNA repair and damage response.
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Dano ao DNA , Técnicas Genéticas , Mapeamento Cromossômico , DNA/genética , DNA/metabolismo , Adutos de DNA , Reparo do DNA/genética , Fatores de Transcrição/genéticaRESUMO
Multidrug-resistant tuberculosis (MDR-TB) continues to spread worldwide and remains one of the leading causes of death among infectious diseases. The enoyl-acyl carrier protein reductase (InhA) belongs to FAS-II family and is essential for the formation of the Mycobacterium tuberculosis cell wall. Recent years, InhA direct inhibitors have been extensively studied to overcome MDR-TB. However, there are still no inhibitors that have entered clinical research. Here, the ensemble docking-based virtual screening along with biological assay were used to identify potent InhA direct inhibitors from Chembridge, Chemdiv, and Specs. Ultimately, 34 compounds were purchased and first assayed for the binding affinity, of which four compounds can bind InhA well with KD values ranging from 48.4 to 56.2 µM. Among them, compound 9,222,034 has the best inhibitory activity against InhA enzyme with an IC50 value of 18.05 µM. In addition, the molecular dynamic simulation and binding free energy calculation indicate that the identified compounds bind to InhA with "extended" conformation. Residue energy decomposition shows that residues such as Tyr158, Met161, and Met191 have higher energy contributions in the binding of compounds. By analyzing the binding modes, we found that these compounds can bind to a hydrophobic sub-pocket formed by residues Tyr158, Phe149, Ile215, Leu218, etc., resulting in extensive van der Waals interactions. In summary, this study proposed an efficient strategy for discovering InhA direct inhibitors through ensemble docking-based virtual screening, and finally identified four active compounds with new skeletons, which can provide valuable information for the discovery and optimization of InhA direct inhibitors.
Assuntos
Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Humanos , Antituberculosos/farmacologia , Antituberculosos/química , Simulação de Dinâmica Molecular , Conformação Molecular , Proteínas de Bactérias/química , Simulação de Acoplamento Molecular , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/químicaRESUMO
BACKGROUND: Growing evidence has suggested that Type I Interferon (I-IFN) plays a potential role in the pathogenesis of Down Syndrome (DS). This work investigates the underlying function of MX1, an effector gene of I-IFN, in DS-associated transcriptional regulation and phenotypic modulation. METHODS: We performed assay for transposase-accessible chromatin with high-throughout sequencing (ATAC-seq) to explore the difference of chromatin accessibility between DS derived amniocytes (DSACs) and controls. We then combined the annotated differentially expressed genes (DEGs) and enriched transcriptional factors (TFs) targeting the promoter region from ATAC-seq results with the DEGs in RNA-seq, to identify key genes and pathways involved in alterations of biological processes and pathways in DS. RESULTS: Binding motif analysis showed a significant increase in chromatin accessibility of genes related to neural cell function, among others, in DSACs, which is primarily regulated by members of the activator protein-1 (AP-1) transcriptional factor family. Further studies indicated that MX Dynamin Like GTPase 1 (MX1), defined as one of the key effector genes of I-IFN, is a critical upstream regulator. Its overexpression induced expression of AP-1 TFs and mediated inflammatory response, thus leading to decreased cellular viability of DS cells. Moreover, treatment with specific AP-1 inhibitor T-5224 improved DS-associated phenotypes in DSACs. CONCLUSIONS: This study demonstrates that MX1-mediated AP-1 activation is partially responsible for cellular dysfunction of DS. T-5224 effectively ameliorated DS-associated phenotypes in DSACs, suggesting it as a potential treatment option for DS patients.
Assuntos
Síndrome de Down , Fator de Transcrição AP-1 , Humanos , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , Sequenciamento de Cromatina por Imunoprecipitação , RNA-Seq , Síndrome de Down/tratamento farmacológico , Síndrome de Down/genética , Cromatina , Proteínas de Resistência a Myxovirus/genética , Proteínas de Resistência a Myxovirus/metabolismoRESUMO
Targeting of the PD-1/PD-L1 immunologic checkpoint is believed to have provided a real breakthrough in the field of cancer therapy in recent years. Due to the intrinsic limitations of antibodies, the discovery of small-molecule inhibitors blocking PD-1/PD-L1 interaction has gradually opened valuable new avenues in the past decades. In an effort to discover new PD-L1 small molecular inhibitors, we carried out a structure-based virtual screening strategy to rapidly identify the candidate compounds. Ultimately, CBPA was identified as a PD-L1 inhibitor with a KD value at the micromolar level. It exhibited effective PD-1/PD-L1 blocking activity and T-cell-reinvigoration potency in cell-based assays. CBPA could dose-dependently elevate secretion levels of IFN-γ and TNF-α in primary CD4+ T cells in vitro. Notably, CBPA exhibited significant in vivo antitumor efficacy in two different mouse tumor models (a MC38 colon adenocarcinoma model and a melanoma B16F10 tumor model) without the induction of observable liver or renal toxicity. Moreover, analyses of the CBPA-treated mice further showed remarkably increased levels of tumor-infiltrating CD4+ and CD8+ T cells and cytokine secretion in the tumor microenvironment. A molecular docking study suggested that CBPA embedded relatively well into the hydrophobic cleft formed by dimeric PD-L1, occluding the PD-1 interaction surface of PD-L1. This study suggests that CBPA could work as a hit compound for the further design of potent inhibitors targeting the PD-1/PD-L1 pathway in cancer immunotherapy.
Assuntos
Inibidores de Checkpoint Imunológico , Receptor de Morte Celular Programada 1 , Animais , Camundongos , Adenocarcinoma/metabolismo , Antígeno B7-H1/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Neoplasias do Colo/metabolismo , Simulação de Acoplamento Molecular , Receptor de Morte Celular Programada 1/metabolismo , Microambiente Tumoral , Inibidores de Checkpoint Imunológico/química , Inibidores de Checkpoint Imunológico/farmacologiaRESUMO
The regulation of T cell receptor Tcra gene rearrangement has been extensively studied. The enhancer Eα plays an essential role in Tcra rearrangement by establishing a recombination centre in the Jα array and a chromatin hub for interactions between Vα and Jα genes. But the mechanism of the Eα and its downstream CTCF binding site (here named EACBE) in dynamic chromatin regulation is unknown. The Hi-C data showed that the EACBE is located at the sub-TAD boundary which separates the Tcra-Tcrd locus and the downstream region including the Dad1 gene. The EACBE is required for long-distance regulation of the Eα on the proximal Vα genes, and its deletion impaired the Tcra rearrangement. We also noticed that the EACBE and Eα regulate the genes in the downstream sub-TAD via asymmetric chromatin extrusion. This study provides a new insight into the role of CTCF binding sites at TAD boundaries in gene regulation.
Assuntos
Fator de Ligação a CCCTC/metabolismo , Cromatina/metabolismo , Elementos Facilitadores Genéticos , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T gama-delta/genética , Animais , Proteínas Reguladoras de Apoptose/genética , Sítios de Ligação , Fator de Ligação a CCCTC/genética , Cromatina/genética , Regulação da Expressão Gênica , Rearranjo Gênico da Cadeia alfa dos Receptores de Antígenos dos Linfócitos T , Proteínas de Homeodomínio/genética , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Timo/citologiaRESUMO
Given the current epidemic of multidrug-resistant tuberculosis, there is an urgent need to develop new drugs to combat drug-resistant tuberculosis. Direct inhibitors of the InhA target do not require activation and thus can overcome drug resistance caused by mutations in drug-activating enzymes. In this work, the binding thermodynamic and kinetic information of InhA to its direct inhibitors, phenoxyphenol derivatives, were explored through multiple computer-aided drug design (CADD) strategies. The results show that the van der Waals interactions were the main driving force for protein-ligand binding, among which hydrophobic residues such as Tyr158, Phe149, Met199 and Ile202 have high energy contribution. The AHRR pharmacophore model generated by multiple ligands demonstrated that phenoxyphenol derivatives inhibitors can form pi-pi stacking and hydrophobic interactions with InhA target. In addition, the order of residence time predicted by random acceleration molecular dynamics was consistent with the experimental values. The intermediate states of these inhibitors could form hydrogen bonds and van der Waals interactions with surrounding residues during dissociation. Overall, the binding and dissociation mechanisms at the atomic level obtained in this work can provide important theoretical guidance for the development of InhA direct inhibitors with higher activity and proper residence time.
Assuntos
Antituberculosos , Mycobacterium tuberculosis , Antituberculosos/química , Antituberculosos/farmacologia , Proteínas de Bactérias/metabolismo , Ligantes , Mycobacterium tuberculosis/metabolismo , Oxirredutases/metabolismo , TermodinâmicaRESUMO
The V(D)J recombination is essential for generating a highly diverse repertoire of antigen receptors expressed on T and B lymphocytes. Here, we developed a linear-amplification VDJ-seq technique for quantifying V(D)J recombination of antigen receptor genes. This technique takes advantage of linear amplification using in vitro transcription and reverse transcription to avoid bias generated by the PCR amplification of low copy number of target DNA. The unrearranged alleles are removed by in vitro cleavage with the CRISPR-Cas9 system. The linear-amplification VDJ-seq assay was applied in quantification of the Vκ-Jκ recombination of the mouse Igκ gene with Jκ capture primers. The Jκ genes were detected in 95.86% of clean reads with more than half containing the Vκ gene, indicating high specificity of capturing and amplification. We also applied this approach to quantify the usage of Jα within the Trav12 gene family of the Tcra gene.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala/métodos , Imunoglobulinas/genética , Receptores de Antígenos de Linfócitos T/genética , Animais , Sistemas CRISPR-Cas , Camundongos , Análise de Sequência de DNA , Recombinação V(D)JRESUMO
The specific properties of carbon nanoparticles (NPs) have attracted great attention in applications in biotechnology and biomedicine, e.g., in the field of amyloidosis. To date, it is still indefinable whether carbon NPs would promote or inhibit the fibril formation of amyloid proteins. Here, to uncover the effects of carbon nanoparticles (NPs) including graphene and carbon nanotubes on the aggregation of prion proteins, whose misfolding and aggregation will lead to prion diseases, a ThT fluorescence assay and a molecular dynamics (MD) simulation were performed. The ThT fluorescence assay reveals that both graphene and carbon nanotubes can inhibit the fibril formation of prion proteins, especially graphene. Further MD simulation of the PrP127-147 tetramer with or without carbon NPs suggests that the interactions between prion proteins and carbon NPs reduce the aggregation tendency of PrP127-147 by decreasing the interpeptide interactions and thus inhibiting ß-sheet formation. Meanwhile, aromatic residues greatly contribute to the inhibition effects of carbon NPs by a π-π stacking interaction. The obtained results can increase our understanding on the interaction between nanoparticles and amyloid-related proteins.
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Carbono/farmacologia , Nanopartículas , Nanotubos de Carbono , Proteínas Priônicas/metabolismo , Agregados Proteicos , Carbono/química , Grafite/química , Grafite/farmacologia , Humanos , Simulação de Dinâmica Molecular , Nanomedicina , Nanopartículas/química , Nanotubos de Carbono/química , Doenças Priônicas/metabolismo , Doenças Priônicas/terapia , Proteínas Priônicas/química , Agregados Proteicos/efeitos dos fármacos , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/terapiaRESUMO
As the broad application of graphene in the biomedical field, it is urgent and important to evaluate how the graphene affects the structure and function of the proteins in our body, especially the amyloid-related proteins. Prion protein, as a typical amyloid protein, it misfolding and aggregation will lead to serious prion diseases. To explore if graphene promotes or inhibits the formation of amyloid, here, we combined the experimental and molecular dynamics (MD) simulation methods to study the influence of graphene on the globular domain of prion protein (PrP117-231). The results from fluorescence quenching and circular dichroism spectrum showed that the addition of graphene changed the secondary structure of prion protein largely, mainly reflecting in the reduced α-helix structure and the increased coil structure, indicating graphene may strengthen the misfolding inclination of prion. To further uncover the mechanism of conformational change of prion under the induction of graphene, the all-atoms MD simulations in explicit solvent were performed. Our simulations suggest that prion protein can be quickly and tightly adsorbed onto graphene together with the weak conformational rearrangement and may reorient when approaching the surface. The Van der Waals' force drive the adsorption process. In the induction of graphene, H1 and S2-H2 loop regions of prion become unstable and prion begins to misfold partially. Our work shows that graphene can induce the misfolding of prion protein and may cause the potential risk to biosystems.
Assuntos
Grafite/química , Proteínas Priônicas/química , Humanos , Simulação de Dinâmica Molecular , Príons , Estrutura Secundária de ProteínaRESUMO
Conformational conversion of the normal cellular prion protein, PrPC, into the misfolded isoform, PrPSc, is considered to be a central event in the development of fatal neurodegenerative diseases. Stabilization of prion protein at the normal cellular form (PrPC) with small molecules is a rational and efficient strategy for treatment of prion related diseases. However, few compounds have been identified as potent prion inhibitors by binding to the normal conformation of prion. In this work, to rational screening of inhibitors capable of stabilizing cellular form of prion protein, multiple approaches combining docking-based virtual screening, steady-state fluorescence quenching, surface plasmon resonance and thioflavin T fluorescence assay were used to discover new compounds interrupting PrPC to PrPSc conversion. Compound 3253-0207 that can bind to PrPC with micromolar affinity and inhibit prion fibrillation was identified from small molecule databases. Molecular dynamics simulation indicated that compound 3253-0207 can bind to the hotspot residues in the binding pocket composed by ß1, ß2 and α2, which are significant structure moieties in conversion from PrPC to PrPSc.
Assuntos
Príons , Avaliação Pré-Clínica de Medicamentos , Simulação de Dinâmica Molecular , Fármacos Neuroprotetores/química , Doenças Priônicas/tratamento farmacológico , Príons/antagonistas & inibidores , Príons/metabolismo , Ligação Proteica , Conformação Proteica , Relação Estrutura-Atividade , Ressonância de Plasmônio de SuperfícieRESUMO
BACKGROUND: Acute-on-chronic liver failure (ACLF) is a major cause of hepatic death in the world, but no population-based studies have evaluated the incidence of ACLF. This study was conducted to determine the incidence and short-term outcomes of ACLF in a region of Eastern China. METHODS: In this prospective cross-sectional study, we collected data from public hospitals in Nantong city between January 1, 2005, and December 31, 2014. All hospitals with admission potential for ACLF patients were included. The primary outcome was ACLF defined as severe jaundice and coagulopathy with underlying chronic liver disease, according to diagnostic and laboratory criteria suggested by Chinese Society for Hepatology (CSH). RESULTS: During the 10-year period, a consecutive sample of 1934 ACLF patients was included in this study. The overall ACLF incidence rate over the 10-year period was 2.53 (95% confidence interval, 2.16-2.91) per 100,000 population per year, decreasing from 3.35 in 2005 to 2.06 in 2014. Chronic hepatitis B virus (HBV) infection was the leading cause of chronic liver disease and HBV reactivation was the most common cause of acute hepatic event. The 28-day mortality for the ACLF patients had a clear decline during the study period, form 50.39% in 2005 to 35.44% in 2014. CONCLUSIONS: In the Eastern China population, the incidence of ACLF is decreasing and the prognosis improving. Short-term mortality was associated with the presence of cirrhosis and growing age. While ACLF remains a life-threatening disorder, our findings suggest that nationwide and long-term cohorts should be conducted for the natural history of ACLF.
Assuntos
Insuficiência Hepática Crônica Agudizada/epidemiologia , Hepatite B Crônica/complicações , Cirrose Hepática/epidemiologia , Insuficiência Hepática Crônica Agudizada/etiologia , Insuficiência Hepática Crônica Agudizada/mortalidade , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , China/epidemiologia , Estudos Transversais , Feminino , Hepatite B Crônica/epidemiologia , Humanos , Incidência , Cirrose Hepática/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Adulto JovemRESUMO
Prion diseases are a group of fatal neurodegenerative diseases caused by the misfolding and aggregation of prion protein (PrP), and the inhibition of PrP aggregation is one of the most effective therapeutic strategies. Proanthocyanidin B2 (PB2) and B3 (PB3), the effective natural antioxidants have been evaluated for the inhibition of amyloid-related protein aggregation. Since PrP has similar aggregation mechanism with other amyloid-related proteins, will PB2 and PB3 affect the aggregation of PrP? In this paper, experimental and molecular dynamics (MD) simulation methods were combined to investigate the influence of PB2 and PB3 on PrP aggregation. Thioflavin T assays showed PB2 and PB3 could inhibit PrP aggregation in a concentrate-dependent manner in vitro. To understand the underlying mechanism, we performed 400 ns all-atom MD simulations. The results suggested PB2 could stabilize the α2 C-terminus and the hydrophobic core of protein by stabilizing two important salt bridges R156-E196 and R156-D202, and consequently made global structure of protein more stable. Surprisingly, PB3 could not stabilize PrP, which may inhibit PrP aggregation through a different mechanism. Since dimerization is the first step of aggregation, will PB3 inhibit PrP aggregation by inhibiting the dimerization? To verify our assumption, we then explored the effect of PB3 on protein dimerization by performing 800 ns MD simulations. The results suggested PB3 could reduce the residue contacts and hydrogen bonds between two monomers, preventing dimerization process of PrP. The possible inhibition mechanism of PB2 and PB3 on PrP aggregation could provide useful information for drug development against prion diseases.Communicated by Ramaswamy H. Sarma.
Assuntos
Doenças Priônicas , Príons , Proantocianidinas , Humanos , Simulação de Dinâmica Molecular , Proantocianidinas/farmacologia , Proteínas Priônicas/químicaRESUMO
Abnormal cardiac development has been observed in individuals with Cornelia de Lange syndrome (CdLS) due to mutations in genes encoding members of the cohesin complex. However, the precise role of cohesin in heart development remains elusive. In this study, we aimed to elucidate the indispensable role of SMC3, a component of the cohesin complex, in cardiac development and its underlying mechanism. Our investigation revealed that CdLS patients with SMC3 mutations have high rates of congenital heart disease (CHD). We utilized heart-specific Smc3-knockout (SMC3-cKO) mice, which exhibit varying degrees of outflow tract (OFT) abnormalities, to further explore this relationship. Additionally, we identified 16 rare SMC3 variants with potential pathogenicity in individuals with isolated CHD. By employing single-nucleus RNA sequencing and chromosome conformation capture high-throughput genome-wide translocation sequencing, we revealed that Smc3 deletion downregulates the expression of key genes, including Ets2, in OFT cardiac muscle cells by specifically decreasing interactions between super-enhancers (SEs) and promoters. Notably, Ets2-SE-null mice also exhibit delayed OFT development in the heart. Our research revealed a novel role for SMC3 in heart development via the regulation of SE-associated genes, suggesting its potential relevance as a CHD-related gene and providing crucial insights into the molecular basis of cardiac development.
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Low-alkali borosilicate glass was used as the immobilization substrate, and Ce was used to replicate the trivalent and tetravalent actinides, in order to create simulated waste glass through melt heat treatment. The valence of Ce and solubility of CeO2 in waste glass were studied as well as its network structure and thermal and chemical stability. The solubility of Ce in waste glass was examined by XRD and SEM. The network structure was examined by Raman spectroscopy. The valence of Ce was determined by X-ray photoelectron spectroscopy. Thermal analysis and product consistency (PCT) were employed to determine the thermal and chemical stability of waste glasses. The results show that the solubility of cerium in low-alkali borosilicate glasses is at least 25.wt.% and precipitates a spherical CeO2 crystalline phase when it exceeds the solid solution limit; Ce is immobilized in the glass by entering the interstices of the glass network. Depolymerization and the transition from [BO3] to [BO4] occurs when CeO2 doping levels rise. About 60 percent of Ce4+ is converted to Ce3+, and the thermal stability of glass rises then falls with the increase of CeO2. All samples exhibit strong leaching resistance, with the average mass loss of Ce at 28 days being less than 10-4 gm-2d-1.
RESUMO
In this paper, the effect of doping phosphorus in a borosilicate glass matrix to improve the solubility of Mo was investigated by X-ray diffraction (XRD), Raman, and solid-state nuclear magnetic resonance (NMR) spectroscopy, and the effectiveness of Na content on P species inhibiting the growth of the crystallization of Mo was assessed. The results indicate that phosphate-doped borosilicate glass can host 4 mol% of Mo, and that such a borosilicate glass matrix could only accommodate 1 mol% of Mo without phosphate doping. The effectiveness of phosphorus may be correlated with the Na content in borosilicate glass, and a high Na content borosilicate glass matrix requires more P doping to accommodate Mo. In addition, incorporating large amounts of P can compromise the aqueous durability of the glass matrix.
RESUMO
CD4+ and CD8+ double-positive (DP) thymocytes play a crucial role in T cell development in the thymus. DP cells rearrange the T cell receptor gene Tcra to generate T cell receptors with TCRß. DP cells differentiate into CD4 or CD8 single-positive (SP) thymocytes, regulatory T cells, or invariant nature kill T cells (iNKT) in response to TCR signaling. Chromatin organizer SATB1 is highly expressed in DP cells and is essential in regulating Tcra rearrangement and differentiation of DP cells. Here we explored the mechanism of SATB1 orchestrating gene expression in DP cells. Single-cell RNA sequencing shows that Satb1 deletion changes the cell identity of DP thymocytes and down-regulates genes specifically and highly expressed in DP cells. Super-enhancers regulate the expressions of DP-specific genes, and our Hi-C data show that SATB1 deficiency in thymocytes reduces super-enhancer activity by specifically decreasing interactions among super-enhancers and between super-enhancers and promoters. Our results reveal that SATB1 plays a critical role in thymocyte development to promote the establishment of DP cell identity by globally regulating super-enhancers of DP cells at the chromatin architectural level.
Assuntos
Proteínas de Ligação à Região de Interação com a Matriz , Timócitos , Antígenos CD4/genética , Antígenos CD4/metabolismo , Linfócitos T CD4-Positivos/metabolismo , Antígenos CD8/genética , Antígenos CD8/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular/genética , Cromatina/metabolismo , Proteínas de Ligação à Região de Interação com a Matriz/genética , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Timo/metabolismoRESUMO
The La2O3-doped basaltic glass simulated high-level waste form (HLW) was prepared by the solid-state melt method. The simulated waste La2O3 maximum loading and the doping effect on structure, thermal stability, leaching behavior, density, and hardness of basaltic glasses were studied. XRD and SEM results show that the simulated waste loading of La2O3 in basaltic glass can be up to ~46 wt.%, and apatite (CaLa4(SiO4)3O) precipitates when the content of La2O3 reaches 56 wt.%. Raman results indicate that the addition of La2O3 breaks the Si-O-Si bond of large-membered and four-membered, but the number of A13+ involved in the formation of the network increase. Low content of La2O3 can help to repair the glass network, but it destroys the network as above 26 wt.%. DSC results show the thermal stability of simulated waste forms first increases and then decreases with the increase of La2O3 content. With the increase of La2O3 content, the density of the simulated waste form increases, and the hardness decreases. The leaching chemical stability of samples was evaluated by the ASTM Product Consistency Test (PCT) Method, which show that all the samples have good chemical stability. The leaching rates of La and Fe are three orders of magnitude lower than those of the other elements. Among them, L36 has the best comprehensive leaching performance.
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FKBP51 is well-known as a cochaperone of Hsp90 machinery and implicated in many human diseases including stress-related diseases, tau-mediated neurodegeneration and cancers, which makes FKBP51 an attractive drug target for the therapy of FKBP51-associated diseases. However, it has been reported that only nature product rapamycin, cyclosporine A, FK506 and its derivatives exhibit good binding affinities when bound to FKBP51 by now. Given the advantages of peptide-inhibitors, we designed and obtained 20 peptide-inhibitor hits through structure-based drug design. We further characterized the interaction modes of the peptide-inhibitor hits on the FK1 domain of FKBP51 by biochemical and structural biology methods. Structural analysis revealed that peptide-inhibitor hits form U-shaped conformations and occupy the FK506 binding pocket and share similar interaction modes with FK506. Using molecular dynamics simulations, we delved into the interaction dynamics and found that hits are anchored to the FK506 binding pocket in a quite stable conformation. Meanwhile, it was shown that interactions between FK1 and peptide-inhibitor hits are mainly attributed to the hydrogen bond networks comprising I87 and Y113 and FPF cores of peptide-inhibitors involved extensive hydrophobic interactions. We presumed that the peptide design strategy based on the small molecule structure probably shed new lights on the peptide-inhibitor discovery of other targets. The findings presented here could also serve as a structural basis and starting point facilitating the optimization and generation of FKBP51 peptide-inhibitors with better bio-activities.
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In order to increase the loading of rare earth- and molybdenum-rich high-level waste in the waste forms, zirconolite- and powellite-based multi-phase borosilicate glass-ceramics were synthesized via an in-situ heat treatment method. The effects of the CTZ (CaO, TiO2 and ZrO2) content on the crystallization, microstructure and aqueous durability of the multi-phase borosilicate glass-ceramics were studied. The results indicate that the increase of CTZ content can promote crystallization. The glass-ceramics presented even structures when the CTZ content was ≥ 40 wt%. For the glass-ceramic with 40 wt% CTZ, only zirconolite and powellite crystals were detected and powellite crystals were mainly distributed around zirconolite, whereas for the glass-ceramics with 50 wt% CTZ, perovskite was detected. Furthermore, the leaching rates of Na, Ca, Mo and Nd were in the ×10-3, ×10-4, ×10-3 and ×10-5 g·m-2·d·-1 orders of magnitude on the 28th leaching day, respectively.