Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 62
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Polymers (Basel) ; 16(17)2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39274110

RESUMO

This study investigated the enhancing effects of the temperature-resistant polymer Poly(ethylene-co-N-methylbutenoyl carboxylate-co-styrenesulfonate-co-pyrrolidone) (hereinafter referred to as Z364) on the performance of cocamidopropyl hydroxy sulfobetaine (CHSB) foam under high-temperature and high-salinity conditions. The potential of this enhanced foam system for mobility control during heavy oil thermal recovery processes was also evaluated. Through a series of experiments, including foam stability tests, surface tension measurements, rheological assessments, and parallel core flooding experiments, we systematically analyzed the interaction between the Z364 polymer and CHSB surfactant on foam performance. The results indicated that the addition of Z364 significantly improved the strength, thermal resistance, and salt tolerance of CHSB foam. Furthermore, the adsorption of CHSB on the polymer chains enhanced the salt resistance of the polymer itself, particularly demonstrating stronger blocking effects in high-permeability cores. The experimental findings showed that Z364 increased the viscosity of the liquid film, slowed down liquid drainage, and reduced gas diffusion, effectively extending the half-life of CHSB foam and improving its stability under high-temperature conditions. Additionally, in parallel core flooding experiments, the polymer-enhanced foam exhibited significant flow diversion effects in both high-permeability and low-permeability cores, effectively directing more fluid into low-permeability channels and improving fluid distribution in heterogeneous reservoirs. Overall, Z364 polymer-enhanced CHSB foam demonstrated superior mobility control during heavy oil thermal recovery, offering new technical insights for improving the development efficiency of high-temperature, high-salinity reservoirs.

2.
J Agric Food Chem ; 72(35): 19494-19504, 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39168117

RESUMO

Tropomyosin was reported as an important allergen in Crassostrea angulata and designated as Cra a 1. The localization of the T cell epitopes and the reduction of the immunoreactivity of Cra a 1 are still lacking. In this study, four T cell epitopes were identified by using wild-type Cra a 1 (wtCra a 1)-immunized mouse splenocytes cultured with synthetic peptides. The immunoreactivity was maintained after chemical denaturation treatment, indicating that the linear epitope is an immunodominant epitope of wtCra a 1. Furthermore, the hypoallergenic derivative (mCra a 1) was developed by the deletion of linear B cell epitopes and retention of T cell epitopes. mCra a 1 could stimulate CD4+T cell proliferation and upregulate interleukin-10 secretion. Overall, basophil activation by mCra a 1 was low, but its ability to induce T cell proliferation was retained, suggesting that mCra a 1 may serve as a viable candidate for treating oyster allergy.


Assuntos
Alérgenos , Crassostrea , Epitopos de Linfócito B , Epitopos de Linfócito T , Animais , Camundongos , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/química , Epitopos de Linfócito T/genética , Alérgenos/imunologia , Alérgenos/química , Alérgenos/genética , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito B/química , Epitopos de Linfócito B/genética , Crassostrea/imunologia , Crassostrea/química , Crassostrea/genética , Tropomiosina/imunologia , Tropomiosina/genética , Tropomiosina/química , Camundongos Endogâmicos BALB C , Feminino , Humanos , Proliferação de Células/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Hipersensibilidade a Frutos do Mar/imunologia , Linfócitos T/imunologia , Linfócitos T/efeitos dos fármacos
3.
Angew Chem Int Ed Engl ; : e202408564, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39011605

RESUMO

Proteomics is a powerful method to comprehensively understand cellular posttranslational modifications (PTMs). Due to low abundance, tryptic peptides with PTMs are usually enriched for enhanced coverage by LC-MS/MS. Affinity chromatography for phosphoproteomes by metal-oxide and pan-specific antibodies for lysine acetylome allow identification of tens of thousands of modification sites. Lysine methylation is a significant PTM, however, only hundreds of methylation sites were identified from available approaches. Here we report an aryl diazonium-based chemoselective strategy that enables enrichment of monomethyllysine (Kme1) peptides via covalent bond with extraordinary sensitivity. We identified more than ten thousand Kme1 peptides from diverse cell lines and mouse tissues, that implied wide lysine methylation impact on cellular processes. In addition, we found a significant amount of methyl marks that were not S-adenosyl methionine (SAM)-dependent by isotope labeling experiments. And therefore, this method paves a way to broad application in lysine methylation research and new biology discovery.

4.
Chemistry ; 30(54): e202401961, 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39046730

RESUMO

Sortase-mediated ligation (SML) is a widely used method for peptide and protein ligation due to ease of substrate preparation and fast enzymatic kinetics. But there are drawbacks that limit broader applications. Sorting motif in substrates may not be exposed to sortase efficiently due to folding or aggregation. In addition, the ligation is reversible under transpeptidation equilibrium that restricts ligation yield. Here we report a simple but robust method to overcome such limitations. By employment of sarkosyl, the detergent alters substrate conformation to raise sorting motif accessibility for sortase catalysis. Moreover, transpeptidation becomes irreversible presumably by formation of micelle to shield ligation products from sortase. In consequence, excellent yields were achieved from sortase variants with different substrate specificity. Notably, this method is compatible with peptides or proteins capable of forming liquid-liquid phase separation (LLPS), presenting a powerful approach for the conjugation of aggregation-prone substrates. Therefore, we believe the sarkosyl-enhanced SML could be widely applied in peptide and protein chemistry and the unique irreversible transpeptidation mechanism offers an insight to detergent-driven equilibrium.


Assuntos
Aminoaciltransferases , Proteínas de Bactérias , Cisteína Endopeptidases , Peptídeos , Aminoaciltransferases/metabolismo , Aminoaciltransferases/química , Cisteína Endopeptidases/química , Cisteína Endopeptidases/metabolismo , Especificidade por Substrato , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Cinética , Detergentes/química , Biocatálise
5.
Nat Chem ; 16(8): 1267-1277, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39079947

RESUMO

The identification of readers, an important class of proteins that recognize modified residues at specific sites, is essential to uncover the biological roles of post-translational modifications. Photoreactive crosslinkers are powerful tools for investigating readers. However, existing methods usually employ synthetically challenging photoreactive warheads, and their high-energy intermediates generated upon irradiation, such as nitrene and carbene, may cause substantial non-specific crosslinking. Here we report dimethylsulfonium as a methyllysine mimic that binds to specific readers and subsequently crosslinks to a conserved tryptophan inside the binding pocket through single-electron transfer under ultraviolet irradiation. The crosslinking relies on a protein-templated σ-π electron donor-acceptor interaction between sulfonium and indole, ensuring excellent site selectivity for tryptophan in the active site and orthogonality to other methyllysine readers. This method could escalate the discovery of methyllysine readers from complex cell samples. Furthermore, this photo crosslinking strategy could be extended to develop other types of microenvironment-dependent conjugations to site-specific tryptophan.


Assuntos
Lisina , Compostos de Sulfônio , Triptofano , Triptofano/química , Triptofano/análogos & derivados , Compostos de Sulfônio/química , Lisina/química , Lisina/análogos & derivados , Transporte de Elétrons , Raios Ultravioleta , Reagentes de Ligações Cruzadas/química , Processos Fotoquímicos , Humanos , Proteínas/química
6.
ACS Omega ; 9(24): 26450-26457, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38911716

RESUMO

The modeling of ceramics with complex geometric structures currently depends on the handcrafted mode, with long cycles, high costs, and low efficiency; additive manufacturing (AM) technology can solve this problem well. Herein, the porcelain clay paste was successfully prepared for the direct ink writing (DIW) 3D printing process of ceramics with complex geometric structures, and the effects of sodium citrate (SC) content on the rheological properties and DIW 3D printability of the porcelain clay paste were investigated in detail. The SC has a vital role in the rheological behavior of porcelain clay paste. Adding SC increases the absolute zeta potential and decreases the viscosity of the paste, while a high SC content will lead to a low storage modulus of the paste. The porcelain clay paste with an SC content of 0.05% and a paste solid content of 75% possesses suitable rheological properties and a storage modulus for DIW 3D printing. The as-prepared porcelain clay paste has high DIW 3D printability at a pressure of 0.5 MPa, and a 3D-printed green body with a well-densified structure can be achieved. After being sintered, the 3D-printed ceramic exhibits high densification and mechanical properties. A green body with complex geometric structures is quickly and precisely modeled by the DIW 3D printing process with the resultant porcelain clay paste as the raw material. This work provides a practical approach to rapidly fabricating ceramics with complex geometrical structures.

7.
Adv Sci (Weinh) ; 11(32): e2309617, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38889308

RESUMO

The physiological interactions between the peripheral and central auditory systems are crucial for auditory information transmission and perception, while reliable models for auditory neural circuits are currently lacking. To address this issue, mouse and human neural pathways are generated by utilizing a carbon nanotube nanofiber system. The super-aligned pattern of the scaffold renders the axons of the bipolar and multipolar neurons extending in a parallel direction. In addition, the electrical conductivity of the scaffold maintains the electrophysiological activity of the primary mouse auditory neurons. The mouse and human primary neurons from peripheral and central auditory units in the system are then co-cultured and showed that the two kinds of neurons form synaptic connections. Moreover, neural progenitor cells of the cochlea and auditory cortex are derived from human embryos to generate region-specific organoids and these organoids are assembled in the nanofiber-combined 3D system. Using optogenetic stimulation, calcium imaging, and electrophysiological recording, it is revealed that functional synaptic connections are formed between peripheral neurons and central neurons, as evidenced by calcium spiking and postsynaptic currents. The auditory circuit model will enable the study of the auditory neural pathway and advance the search for treatment strategies for disorders of neuronal connectivity in sensorineural hearing loss.


Assuntos
Nanotubos de Carbono , Nanotubos de Carbono/química , Humanos , Animais , Camundongos , Vias Auditivas/fisiologia , Córtex Auditivo/fisiologia , Neurônios/fisiologia , Cóclea/fisiologia
8.
Pharmacol Res ; 205: 107229, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38782148

RESUMO

After long-term clinical application, traditional Chinese medicine (TCM) has accumulated rich experience in the stroke treatment. Huang-Qi-Long-Dan Granule (HQLDG) is a TCM formula that has been used in clinical for the treatment of acute ischemic stroke. However, its mechanism against ischemic stroke is still unknown. This study aimed to identify HQLDG's effect against ischemic stroke and explore its underlying mechanism. 16s rRNA sequencing, metabolomics/tryptophan (Trp)-targeted metabolomics analysis and transcriptomic analysis were used to investigate HQLDG underlying therapeutic mechanism. Our results revealed that HQLDG significantly decreased the infarct volume, improved mouse behavior and brain slices pathological staining. In addition, it could ameliorate intestinal barrier damage and regulate tight junction gene expression. 16s rRNA, metabolomics and transcriptomics analysis revealed that HQLDG treatment significantly improved the composition of gut microbiota and Trp metabolism pathway, and further downregulated Th17/IL-17 signaling pathway. HQLDG treatment could significantly decrease serum inflammatory cytokines, IL-17A and IL-22; down-regulate Trp metabolism receptor gene (Ahr), inflammatory cytokines genes (IL-17a, IL-22), and an important coding gene for maintaining the mature Th17 (rorc) in both brain and intestinal tissues. In the contrary, after gut microbiota removal, this effect of HQLDG was impaired. HQLDG treated mouse fecal microbiota transplantation also had positive effect against tMCAO injury. Moreover, AhR inhibitor could decrease IL-17A immunofluorescence. These results suggested that the gut microbiota regulation might be an important intermediate in HQLDG against tMCAO injury. HQLDG might exert anti-ischemic stroke effects through the gut microbiota-Trp metabolism-Th17/IL-17 signaling, which provides new insights into HQLDG-mediated prevention in ischemic stroke.


Assuntos
Medicamentos de Ervas Chinesas , Microbioma Gastrointestinal , AVC Isquêmico , Metabolômica , Camundongos Endogâmicos C57BL , Animais , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Microbioma Gastrointestinal/efeitos dos fármacos , Masculino , AVC Isquêmico/metabolismo , AVC Isquêmico/tratamento farmacológico , Camundongos , Triptofano/metabolismo , Astragalus propinquus , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Citocinas/metabolismo , Células Th17/efeitos dos fármacos , Células Th17/metabolismo , Infarto da Artéria Cerebral Média/tratamento farmacológico , Infarto da Artéria Cerebral Média/metabolismo , Modelos Animais de Doenças , Multiômica , Receptores de Hidrocarboneto Arílico , Fatores de Transcrição Hélice-Alça-Hélice Básicos
9.
Materials (Basel) ; 17(7)2024 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-38612119

RESUMO

The restoration of ancient ceramics has attracted widespread attention as it can reveal the overall appearance of ancient ceramics as well as the original information and artistic charm of cultural relics. However, traditional manual restoration is constrained due to its time-consuming nature and susceptibility to damaging ancient ceramics. Herein, a three-dimensional (3D) printing technique was employed to accurately restore Chinese Yuan Dynasty Longquan celadon using hollow Al2O3 microsphere-modified 3D printing paste. The results show that the hollow Al2O3 microsphere content plays a vital role in the printability, physical properties, and firing performance of the modified 3D printing paste. The printed green bodies show no noticeable spacing or voids under moderate rheological conditions. The as-prepared ceramic body modified with 6 wt.% hollow Al2O3 microspheres and fired at 1280 °C exhibits optimal bending strength of 56.66 MPa and a relatively low density of 2.16 g∙cm-3, as well as a relatively uniform longitudinal elastic modulus and hardness along the interlayer. This 3D printing technique based on hollow Al2O3 microsphere-modified paste presents a promising pathway for achieving non-contact and damage-free restoration of cultural relics.

10.
J Agric Food Chem ; 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38598840

RESUMO

Sarcoplasmic calcium-binding protein (Cra a 4) from Crassostrea angulata belongs to the EF-hand superfamily, and understanding of its structure-allergenicity relationship is still insufficient. In this study, chemical denaturants were used to destroy the structure of Cra a 4, showing that disruption of the structure reduced its IgG-/IgE-binding activity. To explore which critical amino acid site affects the allergenicity of Cra a 4, the mutants were obtained by site-directed mutations in the disulfide bonds site (C97), conformational epitopes (I105, D114), or Ca2+-binding region (D106, D110) and their IgG-/IgE-binding activity was reduced significantly using serological tests. Notably, C97A had the lowest immunoreactivity. In addition, two conformational epitopes of Cra 4 were verified. Meanwhile, the increase of the α-helical content, surface hydrophobicity, and surface electrostatic potential of C97A affected its allergenicity. Overall, the understanding of the structure-allergenicity relationship of Cra a 4 allowed the development of a hypoallergenic mutant.

11.
Small ; 20(1): e2305009, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37641184

RESUMO

As a high energy density power system, lithium-carbon dioxide (Li-CO2 ) batteries play an important role in addressing the fossil fuel crisis issues and alleviating the greenhouse effect. However, the sluggish transformation kinetic of CO2 and the difficult decomposition of discharge products impede the achievement of large capacity, small overpotential, and long life span of the batteries, which require exploring efficient catalysts to resolve these problems. In this review, the main focus is on the hot spot regulation strategies of the catalysts, which include the modulation of the active sites, the designing of microstructure, and the construction of composition. The recent progress of promising catalysis with hot spot regulated strategies is systematically addressed. Critical challenges are also presented and perspectives to provide useful guidance for the rational design of highly efficient catalysts for practical advanced Li-CO2 batteries are proposed.

12.
Sci Adv ; 9(44): eadf2664, 2023 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-37922362

RESUMO

The mechanical cues of the external microenvironment have been recognized as essential clues driving cell behavior. Although intracellular signals modulating cell fate during sensory epithelium development is well understood, the driving force of sensory epithelium formation remains elusive. Here, we manufactured a hybrid hydrogel with tunable mechanical properties for the cochlear organoids culture and revealed that the extracellular matrix (ECM) drives sensory epithelium formation through shifting stiffness in a stage-dependent pattern. As the driving force, moderate ECM stiffness activated the expansion of cochlear progenitor cell (CPC)-derived epithelial organoids by modulating the integrin α3 (ITGA3)/F-actin cytoskeleton/YAP signaling. Higher stiffness induced the transition of CPCs into sensory hair cells (HCs) through increasing the intracellular Ca2+ signaling mediated by PIEZO2 and then activating KLF2 to accomplish the cell specification . Our results identify the molecular mechanism of sensory epithelium formation guided by ECM mechanical force and contribute to developing therapeutic approaches for HC regeneration.


Assuntos
Matriz Extracelular , Transdução de Sinais , Epitélio , Citoesqueleto de Actina , Diferenciação Celular
13.
Environ Sci Pollut Res Int ; 30(57): 120832-120843, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37945960

RESUMO

Machine learning models for predicting lead adsorption in biochar, based on preparation features, are currently lacking in the environmental field. Existing conventional models suffer from accuracy limitations. This study addresses these challenges by developing back-propagation neural network (BPNN) and random forest (RF) models using selected features: preparation temperature (T), specific surface area (BET), relative carbon content (C), molar ratios of hydrogen to carbon (H/C), oxygen to carbon (O/C), nitrogen to carbon (N/C), and cation exchange capacity (CEC). The RF model outperforms BPNN, improving R2 by 10%. Additional features and particle swarm optimization enhance the RF model's accuracy, resulting in an 8.3% improvement in R2, a decrease in RMSE by up to 56.1%, and a 55.7% reduction in MAE. The importance ranking of features places CEC > C > BET > O/C > H/C > N/C > T, highlighting the significance of CEC in lead adsorption. Strengthening the complexation effect may improve lead removal in biochar. This study contributes valuable insights for predicting and optimizing lead adsorption in biochar, addressing the accuracy gap in existing models. It lays the foundation for future investigations and the development of effective biochar-based solutions for sustainable lead removal in water remediation.


Assuntos
Carvão Vegetal , Chumbo , Adsorção , Carbono , Aprendizado de Máquina
14.
BMC Oral Health ; 23(1): 501, 2023 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-37468947

RESUMO

BACKGROUND: The key to the success of endogenous regeneration is to improve the homing rate of stem cells, and low-energy laser is an effective auxiliary means to promote cell migration and proliferation. The purpose of this study was to observe whether low-energy neodymium (Nd: YAG) laser with appropriate parameters can affect the proliferation and migration of periodontal ligament stem cells (PDLSCs) through SDF-1/CXCR4 pathway. METHODS: h PDLSCs were cultured and identified. CCK8 assay was used to detect the proliferation of h PDLSCs after different power (0, 0.25, 0.5, 1, and 1.5 W) Nd: YAG laser (MSP, 10 Hz, 30 s, 300 µ m) irradiation at 2th, 3rd,5th, and 7th days, and the optimal laser irradiation parameters were selected for subsequent experiments. Then, the cells were categorized into five groups: control group (C), SDF-1 group (S), AMD3100 group (A), Nd: YAG laser irradiation group (N), and Nd: YAG laser irradiation + AMD3100 group (N + A). the migration of h PDLSCs was observed using Transwell, and the SDF-1 expression was evaluated using ELISA andRT-PCR. The SPSS Statistics 21.0 software was used for statistical analysis. RESULTS: The fibroblasts cultured were identified as h PDLSCs. Compared with the C, when the power was 1 W, the proliferation rate of h PDLSCs was accelerated (P < 0.05). When the power was 1.5 W, the proliferation rate decreased (P < 0.05). When the power was 0.25 and 0.5 W, no statistically significant difference in the proliferation rate was observed (P > 0.05). The number of cell perforations values as follows: C (956.5 ± 51.74), A (981.5 ± 21.15), S (1253 ± 87.21), N (1336 ± 48.54), and N + A (1044 ± 22.13), that increased significantly in group N (P < 0.05), but decreased in group N + A (P < 0.05). The level of SDF-1 and the expression level of SDF-1 mRNA in groups N and N + A was higher than that in group C (P < 0.05) but lower than that in group A (P < 0.05). CONCLUSIONS: Nd: YAG laser irradiation with appropriate parameters provides a new method for endogenous regeneration of periodontal tissue. SDF-1/CXCR4 signaling pathway may be the mechanism of LLLT promoting periodontal regeneration.


Assuntos
Movimento Celular , Lasers de Estado Sólido , Ligamento Periodontal , Células-Tronco , Humanos , Benzilaminas , Ligamento Periodontal/citologia , Receptores CXCR4 , Células-Tronco/citologia
15.
BMC Plant Biol ; 23(1): 318, 2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37316771

RESUMO

BACKGROUND: The genus Rosa (Rosaceae) contains approximately 200 species, most of which have high ecological and economic values. Chloroplast genome sequences are important for studying species differentiation, phylogeny, and RNA editing. RESULTS: In this study, the chloroplast genomes of three Rosa species, Rosa hybrida, Rosa acicularis, and Rosa rubiginosa, were assembled and compared with other reported Rosa chloroplast genomes. To investigate the RNA editing sites in R. hybrida (commercial rose cultivar), we mapped RNA-sequencing data to the chloroplast genome and analyzed their post-transcriptional features. Rosa chloroplast genomes presented a quadripartite structure and had highly conserved gene order and gene content. We identified four mutation hotspots (ycf3-trnS, trnT-trnL, psbE-petL, and ycf1) as candidate molecular markers for differentiation in the Rosa species. Additionally, 22 chloroplast genomic fragments with a total length of 6,192 bp and > 90% sequence similarity with their counterparts were identified in the mitochondrial genome, representing 3.96% of the chloroplast genome. Phylogenetic analysis including all sections and all subgenera revealed that the earliest divergence in the chloroplast phylogeny roughly distinguished species of sections Pimpinellifoliae and Rosa and subgenera Hulthemia. Moreover, DNA- and RNA-sequencing data revealed 19 RNA editing sites, including three synonymous and 16 nonsynonymous, in the chloroplast genome of R. hybrida that were distributed among 13 genes. CONCLUSIONS: The genome structure and gene content of Rosa chloroplast genomes are similar across various species. Phylogenetic analysis based on the Rosa chloroplast genomes has high resolution. Additionally, a total of 19 RNA editing sites were validated by RNA-Seq mapping in R. hybrida. The results provide valuable information for RNA editing and evolutionary studies of Rosa and a basis for further studies on genomic breeding of Rosa species.


Assuntos
Genoma de Cloroplastos , Rosa , Rosa/genética , Genoma de Cloroplastos/genética , Filogenia , Edição de RNA/genética , Melhoramento Vegetal , RNA
16.
Mol Cell ; 83(13): 2316-2331.e7, 2023 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-37390815

RESUMO

The diabetes-cancer association remains underexplained. Here, we describe a glucose-signaling axis that reinforces glucose uptake and glycolysis to consolidate the Warburg effect and overcome tumor suppression. Specifically, glucose-dependent CK2 O-GlcNAcylation impedes its phosphorylation of CSN2, a modification required for the deneddylase CSN to sequester Cullin RING ligase 4 (CRL4). Glucose, therefore, elicits CSN-CRL4 dissociation to assemble the CRL4COP1 E3 ligase, which targets p53 to derepress glycolytic enzymes. A genetic or pharmacologic disruption of the O-GlcNAc-CK2-CSN2-CRL4COP1 axis abrogates glucose-induced p53 degradation and cancer cell proliferation. Diet-induced overnutrition upregulates the CRL4COP1-p53 axis to promote PyMT-induced mammary tumorigenesis in wild type but not in mammary-gland-specific p53 knockout mice. These effects of overnutrition are reversed by P28, an investigational peptide inhibitor of COP1-p53 interaction. Thus, glycometabolism self-amplifies via a glucose-induced post-translational modification cascade culminating in CRL4COP1-mediated p53 degradation. Such mutation-independent p53 checkpoint bypass may represent the carcinogenic origin and targetable vulnerability of hyperglycemia-driven cancer.


Assuntos
Neoplasias , Proteína Supressora de Tumor p53 , Animais , Camundongos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Glucose , Ubiquitina-Proteína Ligases/metabolismo , Carcinogênese/genética , Transformação Celular Neoplásica/genética
17.
Nat Struct Mol Biol ; 30(6): 753-760, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37081318

RESUMO

SIN3-HDAC (histone deacetylases) complexes have important roles in facilitating local histone deacetylation to regulate chromatin accessibility and gene expression. Here, we present the cryo-EM structure of the budding yeast SIN3-HDAC complex Rpd3L at an average resolution of 2.6 Å. The structure reveals that two distinct arms (ARM1 and ARM2) hang on a T-shaped scaffold formed by two coiled-coil domains. In each arm, Sin3 interacts with different subunits to create a different environment for the histone deacetylase Rpd3. ARM1 is in the inhibited state with the active site of Rpd3 blocked, whereas ARM2 is in an open conformation with the active site of Rpd3 exposed to the exterior space. The observed asymmetric architecture of Rpd3L is different from those of available structures of other class I HDAC complexes. Our study reveals the organization mechanism of the SIN3-HDAC complex and provides insights into the interaction pattern by which it targets histone deacetylase to chromatin.


Assuntos
Proteínas de Saccharomyces cerevisiae , Saccharomycetales , Fatores de Transcrição/metabolismo , Proteínas Repressoras/metabolismo , Saccharomycetales/genética , Saccharomycetales/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Cromatina , Histona Desacetilases/genética
18.
Stem Cell Reports ; 18(1): 319-336, 2023 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-36584686

RESUMO

Functional cochlear hair cells (HCs) innervated by spiral ganglion neurons (SGNs) are essential for hearing, whereas robust models that recapitulate the peripheral auditory circuity are still lacking. Here, we developed cochlear organoids with functional peripheral auditory circuity in a staging three-dimensional (3D) co-culture system by initially reprogramming cochlear progenitor cells (CPCs) with increased proliferative potency that could be long-term expanded, then stepwise inducing the differentiation of cochlear HCs, as well as the outgrowth of neurites from SGNs. The function of HCs and synapses within organoids was confirmed by a series of morphological and electrophysiological evaluations. Single-cell mRNA sequencing revealed the differentiation trajectories of CPCs toward the major cochlear cell types and the dynamic gene expression during organoid HC development, which resembled the pattern of native HCs. We established the cochlear organoids with functional synapses for the first time, which provides a platform for deciphering the mechanisms of sensorineural hearing loss.


Assuntos
Cóclea , Gânglio Espiral da Cóclea , Neurônios/metabolismo , Neuritos/metabolismo , Organoides
19.
Neuropathology ; 43(1): 100-103, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35989547

RESUMO

Primary central nervous system T-cell lymphoma (T-PCNSL) is a rare neoplasm, and its underlying genetic features are poorly understood. Herein, we present the case of a 64-year-old man with T-PCNSL who presented with left-side limb weakness. Brain magnetic resonance imaging revealed a right parietal space-occupying lesion. Immunohistochemically, the tumor was positive for CD3, CD4, CD5, CD8, and CD56, and the Ki-67 labeling index was approximately 20%. These pathological features are consistent with those of T-cell lymphoma. Whole exome sequencing was performed, and we found a variant in the ACSS3 gene that could be related to disease pathogenesis. Our findings may help advance our understanding of the molecular pathogenesis of T-PCNSL. Further molecular analysis of such cases could help to improve adjuvant molecular diagnostic methods and targeted therapies for T-PCNSL.


Assuntos
Neoplasias do Sistema Nervoso Central , Linfoma de Células T , Masculino , Humanos , Pessoa de Meia-Idade , Sequenciamento do Exoma , Neoplasias do Sistema Nervoso Central/patologia , Linfoma de Células T/genética , Encéfalo/patologia , Genômica
20.
Angew Chem Int Ed Engl ; 61(52): e202209945, 2022 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-36305862

RESUMO

The post-translational modifications (PTMs) on the tail of histone H3 control chromatin structure and influence epigenetics and gene expression. The current chemical methods including unnatural amino acid incorporation and protein splicing enable preparations of the histone with diverse PTMs in cellular contexts, but they are not applicable to edit native chromatin. The manipulation of histone-modifying enzymes alter the endogenous histone PTMs but the lack of specificity of most histone-modifying enzymes prevents precise control of specific H3 tail PTM patterns. Here we report a new method to edit the N-tail of histone H3 via sortase mediated metathesis (SMM). The sortase can install desired PTM patterns into histone H3 on nucleosomes in vitro and in cellulo. This study expands the application scope of sortase from ligation to metathesis in live cells using cell-penetrating peptides (CPPs). In addition, it offers a strategy to edit PTMs of cellular histone H3 with potential for the development of precise epigenome editing.


Assuntos
Cromatina , Histonas , Histonas/química , Processamento de Proteína Pós-Traducional , Nucleossomos , Código das Histonas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA