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1.
Nature ; 567(7749): 525-529, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30814730

RESUMO

T cells become dysfunctional when they encounter self antigens or are exposed to chronic infection or to the tumour microenvironment1. The function of T cells is tightly regulated by a combinational co-stimulatory signal, and dominance of negative co-stimulation results in T cell dysfunction2. However, the molecular mechanisms that underlie this dysfunction remain unclear. Here, using an in vitro T cell tolerance induction system in mice, we characterize genome-wide epigenetic and gene expression features in tolerant T cells, and show that they are distinct from effector and regulatory T cells. Notably, the transcription factor NR4A1 is stably expressed at high levels in tolerant T cells. Overexpression of NR4A1 inhibits effector T cell differentiation, whereas deletion of NR4A1 overcomes T cell tolerance and exaggerates effector function, as well as enhancing immunity against tumour and chronic virus. Mechanistically, NR4A1 is preferentially recruited to binding sites of the transcription factor AP-1, where it represses effector-gene expression by inhibiting AP-1 function. NR4A1 binding also promotes acetylation of histone 3 at lysine 27 (H3K27ac), leading to activation of tolerance-related genes. This study thus identifies NR4A1 as a key general regulator in the induction of T cell dysfunction, and a potential target for tumour immunotherapy.


Assuntos
Regulação da Expressão Gênica/genética , Genoma , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Linfócitos T/metabolismo , Linfócitos T/patologia , Acetilação , Animais , Infecções por Arenaviridae/imunologia , Infecções por Arenaviridae/virologia , Linhagem Celular Tumoral , Colite/imunologia , Colite/patologia , Colite/terapia , Epigênese Genética , Feminino , Histonas/química , Histonas/metabolismo , Tolerância Imunológica/genética , Imunoterapia , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias/imunologia , Neoplasias/patologia , Neoplasias/terapia , Linfócitos T/imunologia , Fator de Transcrição AP-1/metabolismo , Transcrição Gênica
2.
Nano Lett ; 24(5): 1650-1659, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38265360

RESUMO

Precision nanoengineering of porous two-dimensional structures has emerged as a promising avenue for finely tuning catalytic reactions. However, understanding the pore-structure-dependent catalytic performance remains challenging, given the lack of comprehensive guidelines, appropriate material models, and precise synthesis strategies. Here, we propose the optimization of two-dimensional carbon materials through the utilization of mesopores with 5-10 nm diameter to facilitate fluid acceleration, guided by finite element simulations. As proof of concept, the optimized mesoporous carbon nanosheet sample exhibited exceptional electrocatalytic performance, demonstrating high selectivity (>95%) and a notable diffusion-limiting disk current density of -3.1 mA cm-2 for H2O2 production. Impressively, the electrolysis process in the flow cell achieved a production rate of 14.39 mol gcatalyst-1 h-1 to yield a medical-grade disinfectant-worthy H2O2 solution. Our pore engineering research focuses on modulating oxygen reduction reaction activity and selectivity by affecting local fluid transport behavior, providing insights into the mesoscale catalytic mechanism.

3.
Immunity ; 42(4): 613-26, 2015 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-25862091

RESUMO

Epigenetic regulation of lineage-specific genes is important for the differentiation and function of T cells. Ten-eleven translocation (Tet) proteins catalyze 5-methylcytosine (5 mC) conversion to 5-hydroxymethylcytosine (5 hmC) to mediate DNA demethylation. However, the roles of Tet proteins in the immune response are unknown. Here, we characterized the genome-wide distribution of 5 hmC in CD4(+) T cells and found that 5 hmC marks putative regulatory elements in signature genes associated with effector cell differentiation. Moreover, Tet2 protein was recruited to 5 hmC-containing regions, dependent on lineage-specific transcription factors. Deletion of Tet2 in T cells decreased their cytokine expression, associated with reduced p300 recruitment. In vivo, Tet2 plays a critical role in the control of cytokine gene expression in autoimmune disease. Collectively, our findings suggest that Tet2 promotes DNA demethylation and activation of cytokine gene expression in T cells.


Assuntos
Citocinas/biossíntese , Proteínas de Ligação a DNA/imunologia , Epigênese Genética/imunologia , Proteínas Proto-Oncogênicas/imunologia , Células Th1/imunologia , Células Th17/imunologia , 5-Metilcitosina/análogos & derivados , Animais , Diferenciação Celular , Citocinas/imunologia , Citosina/análogos & derivados , Citosina/imunologia , Citosina/metabolismo , DNA/imunologia , DNA/metabolismo , Metilação de DNA , Proteínas de Ligação a DNA/genética , Dioxigenases , Proteína p300 Associada a E1A/genética , Proteína p300 Associada a E1A/imunologia , Regulação da Expressão Gênica , Genoma , Humanos , Camundongos , Camundongos Transgênicos , Proteínas Proto-Oncogênicas/genética , Fator de Transcrição STAT4/genética , Fator de Transcrição STAT4/imunologia , Proteínas com Domínio T/genética , Proteínas com Domínio T/imunologia , Células Th1/citologia , Células Th1/enzimologia , Células Th17/citologia , Células Th17/enzimologia
4.
Fish Shellfish Immunol ; 151: 109717, 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38914179

RESUMO

Aquaculture is one of the fastest growing sectors in global food production, recognized as a significant contributor to poverty alleviation, food security, and income generation. However, the frequent occurrence of diseases caused by pathogen infections result in reduced yields and economic losses, posing a substantial constraint to the sustainable development of aquaculture. Here, our study identified that four catechol compounds, quercetin, luteolin, caffeic acid, and chlorogenic acid, exhibited potent antiparasitic effects against Ichthyophthirius multifiliis in both, in vitro and in vivo. The parasite is recognized as one of the most pathogenic to fish worldwide. Using a combination of in silico methods, the dipeptidyl peptidase (DPP) was identified as a critical target for catechol compounds. The two hydroxyl radicals of the catechol group were essential for its binding to and interacting with the DPP protein. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that catechol compounds disrupt pathways associated with the metabolism and growth of I. multifiliis, thereby exerting antiparasitic effects. Furthermore, these compounds attenuated the expression of proinflammatory cytokines in vivo in fish and promoted macrophage polarization toward M2 phenotype by inhibiting the STAT1 signaling pathway. The dual activity of catechol compounds, acting as both direct antiparasitic and anti-inflammatory agents in fish, offers a promising therapeutic approach for combating I. multifiliis infections in aquaculture.

5.
Mol Biol Rep ; 51(1): 365, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38409611

RESUMO

A low-frequency variant of sushi, von Willebrand factor type A, EGF, and pentraxin domain-containing protein 1 (SVEP1) is associated with the risk of coronary artery disease, as determined by a genome-wide association study. SVEP1 induces vascular smooth muscle cell proliferation and an inflammatory phenotype to promote atherosclerosis. In the present study, qRT‒PCR demonstrated that the mRNA expression of SVEP1 was significantly increased in atherosclerotic plaques compared to normal tissues. Bioinformatics revealed that EGR1 was a transcription factor for SVEP1. The results of the luciferase reporter assay, siRNA interference or overexpression assay, mutational analysis and ChIP confirmed that EGR1 positively regulated the transcriptional activity of SVEP1 by directly binding to its promoter. EGR1 promoted human coronary artery smooth muscle cell (HCASMC) proliferation and migration via SVEP1 in response to oxidized low-density lipoprotein (ox-LDL) treatment. Moreover, the expression level of EGR1 was increased in atherosclerotic plaques and showed a strong linear correlation with the expression of SVEP1. Our findings indicated that EGR1 binding to the promoter region drive SVEP1 transcription to promote HCASMC proliferation and migration.


Assuntos
MicroRNAs , Placa Aterosclerótica , Humanos , Placa Aterosclerótica/metabolismo , Vasos Coronários/metabolismo , Estudo de Associação Genômica Ampla , Movimento Celular , Lipoproteínas LDL/farmacologia , Células Cultivadas , Proliferação de Células/genética , Miócitos de Músculo Liso/metabolismo , MicroRNAs/genética , Proteína 1 de Resposta de Crescimento Precoce/genética , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Moléculas de Adesão Celular/genética
6.
BMC Womens Health ; 24(1): 351, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38890689

RESUMO

BACKGROUND: Observational data indicates a connection between emotional discomfort, such as anxiety and depression, and uterine fibroids (UFs). However, additional investigation is required to establish the causal relationship between them. Hence, we assessed the reciprocal causality between four psychological disorders and UFs utilizing two-sample Mendelian randomization (MR). METHODS: To evaluate the causal relationship between four types of psychological distress (depressive symptoms, severe depression, anxiety or panic attacks, mood swings) and UFs, bidirectional two-sample MR was employed, utilizing single nucleotide polymorphisms (SNPs) associated with these conditions. Both univariate MR (UVMR) and multivariate MR (MVMR) primarily applied inverse variance weighted (IVW) as the method for estimating potential causal effects. Complementary approaches such as MR Egger, weighted median, simple mode, and weighted mode were utilized to validate the findings. To assess the robustness of our MR results, we conducted sensitivity analyses using Cochran's Q-test and the MR Egger intercept test. RESULTS: The results of our UVMR analysis suggest that genetic predispositions to depressive symptoms (Odds Ratio [OR] = 1.563, 95% Confidence Interval [CI] = 1.209-2.021, P = 0.001) and major depressive disorder (MDD) (OR = 1.176, 95% CI = 1.044-1.324, P = 0.007) are associated with an increased risk of UFs. Moreover, the IVW model showed a nominally significant positive correlation between mood swings (OR: 1.578; 95% CI: 1.062-2.345; P = 0.024) and UFs risk. However, our analysis did not establish a causal relationship between UFs and the four types of psychological distress. Even after adjusting for confounders like body mass index (BMI), smoking, alcohol consumption, and number of live births in the MVMR, the causal link between MDD and UFs remained significant (OR = 1.217, 95% CI = 1.039-1.425, P = 0.015). CONCLUSIONS: Our study presents evidence supporting the causal relationship between genetic susceptibility to MDD and the incidence of UFs. These findings highlight the significance of addressing psychological health issues, particularly depression, in both the prevention and treatment of UFs.


Assuntos
Depressão , Leiomioma , Análise da Randomização Mendeliana , Polimorfismo de Nucleotídeo Único , Humanos , Análise da Randomização Mendeliana/métodos , Feminino , Leiomioma/genética , Leiomioma/psicologia , Depressão/epidemiologia , Depressão/genética , Depressão/psicologia , Angústia Psicológica , Predisposição Genética para Doença/psicologia , Ansiedade/epidemiologia , Ansiedade/psicologia , Neoplasias Uterinas/genética , Neoplasias Uterinas/psicologia , Causalidade , Transtorno de Pânico/genética , Transtorno de Pânico/psicologia , Transtorno de Pânico/epidemiologia
7.
BMC Musculoskelet Disord ; 25(1): 32, 2024 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-38178051

RESUMO

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is the most common developmental spine disorder among children. It is characterized by a lateral deviation of the spine that gives rise to the distinctive "S" or "C" shaped bending of the spine. The Lin School of Lingnan Region (LSLR), one of the prominent schools for bare-handed orthopaedic manipulation in southern China, provides preliminary evidences that the orthopaedic manipulation techniques help to correct deviations of the spine. Previous research found that Orthopaedic Manipulation Techniques of LSLR (OMT-LSLR) could reduce the Cobb's angles in patients with AIS. Therefore, the current study aims to investigate the effectiveness and safety of the OMT-LSLR in treating teenagers with AIS. METHODS: In this participant-and-assessor-blinded randomized controlled clinical trial, 50 participants identified AIS without surgical indications will be recruited and randomized into two groups to receive physiotherapy scoliosis-specific exercises training with either orthopaedic manipulation or sham manipulation treatment for 16 weeks, followed by post-treatment visits at week 24. Primary outcome measure is the change of Scoliosis Research Society-22 (SRS-22) questionnaire score. Secondary outcome measures include Traditional Chinese version of Spinal Appearance Questionnaire (TC-SAQ) score, Italian Spine Youth Quality of Life (ISYQOL) score, the change of Cobb's angle measured by Xray, and the change of Cobb's angle, spinal rotation and muscle volume measured by three-dimensional (3D) ultrasound. The trial will be conducted at the Chinese University of Hong Kong Chinese Medicine Specialty Clinic cum Clinical Teaching and Research Centre in Hong Kong (CUHK-CMSCTRC). DISCUSSION: The results of this study will establish comprehensive clinical evidence about the efficacy and safety of the Orthopaedic Manipulation Techniques of the Lin School of Lingnan Region in the Treatment of Adolescent Idiopathic Scoliosis. One of the characteristics of this trial is that it is a participant-and-assessor-blinded randomized controlled clinical trial with sham manipulation. The study would also apply three-dimensional (3D) ultrasound technology to investigate the relationship between the change of the muscle volume and the spinal curve. TRIAL REGISTRATION: The trial is registered on ClinicalTrials.gov (Identifier: NCT05639023 ) on December 6, 2022.


Assuntos
Escoliose , Criança , Humanos , Adolescente , Escoliose/terapia , Escoliose/cirurgia , Manipulação Ortopédica , Qualidade de Vida , Coluna Vertebral , Terapia por Exercício/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto
8.
Angew Chem Int Ed Engl ; : e202403023, 2024 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-38763905

RESUMO

The efficient electrosynthesis of hydrogen peroxide (H2O2) via two-electron oxygen reduction reaction (2e- ORR) in neutral media is undoubtedly a practical route, but the limited comprehension of electrocatalysts has hindered the system advancement. Herein, we present the design of model catalysts comprising mesoporous carbon spheres-supported Pd nanoparticles for H2O2 electrosynthesis at near-zero overpotential with approximately 95% selectivity in a neutral electrolyte. Impressively, the optimized Pd/MCS-8 electrocatalyst in a flow cell device achieves an exceptional H2O2 yield of 15.77 mol gcatalyst-1 h-1, generating a neutral H2O2 solution with an accumulated concentration of 6.43 wt.%, a level sufficiently high for medical disinfection. Finite element simulation and experimental results suggest that mesoporous carbon carriers promote O2 enrichment and localized pH elevation, establishing a favorable microenvironment for 2e- ORR in neutral media. Density functional theory calculations reveal that the robust interaction between Pd nanoparticles and the carbon carriers optimized the adsorption of OOH* at the carbon edge, ensuring high active 2e- process. These findings offer new insights into carbon-loaded electrocatalysts for efficient 2e- ORR in neutral media, emphasizing the role of carrier engineering in constructing favorable microenvironments and synergizing active sites.

9.
Gut ; 72(2): 325-337, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35705369

RESUMO

OBJECTIVE: Programmed cell death protein 1 (PD-1) checkpoint inhibition and adoptive cellular therapy have had limited success in patients with microsatellite stable colorectal cancer liver metastases (CRLM). We sought to evaluate the effect of interleukin 10 (IL-10) blockade on endogenous T cell and chimeric antigen receptor T (CAR-T) cell antitumour function in CRLM slice cultures. DESIGN: We created organotypic slice cultures from human CRLM (n=38 patients' tumours) and tested the antitumour effects of a neutralising antibody against IL-10 (αIL-10) both alone as treatment and in combination with exogenously administered carcinoembryonic antigen (CEA)-specific CAR-T cells. We evaluated slice cultures with single and multiplex immunohistochemistry, in situ hybridisation, single-cell RNA sequencing, reverse-phase protein arrays and time-lapse fluorescent microscopy. RESULTS: αIL-10 generated a 1.8-fold increase in T cell-mediated carcinoma cell death in human CRLM slice cultures. αIL-10 significantly increased proportions of CD8+ T cells without exhaustion transcription changes, and increased human leukocyte antigen - DR isotype (HLA-DR) expression of macrophages. The antitumour effects of αIL-10 were reversed by major histocompatibility complex class I or II (MHC-I or MHC-II) blockade, confirming the essential role of antigen presenting cells. Interrupting IL-10 signalling also rescued murine CAR-T cell proliferation and cytotoxicity from myeloid cell-mediated immunosuppression. In human CRLM slices, αIL-10 increased CEA-specific CAR-T cell activation and CAR-T cell-mediated cytotoxicity, with nearly 70% carcinoma cell apoptosis across multiple human tumours. Pretreatment with an IL-10 receptor blocking antibody also potentiated CAR-T function. CONCLUSION: Neutralising the effects of IL-10 in human CRLM has therapeutic potential as a stand-alone treatment and to augment the function of adoptively transferred CAR-T cells.


Assuntos
Carcinoma , Neoplasias Colorretais , Interleucina-10 , Neoplasias Hepáticas , Receptores de Antígenos Quiméricos , Receptores de Interleucina-10 , Animais , Humanos , Camundongos , Antígeno Carcinoembrionário/imunologia , Carcinoma/imunologia , Carcinoma/secundário , Linfócitos T CD8-Positivos/imunologia , Neoplasias Colorretais/patologia , Imunoterapia Adotiva , Interleucina-10/antagonistas & inibidores , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/secundário , Ativação Linfocitária , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Antígenos Quiméricos/genética , Receptores de Antígenos Quiméricos/metabolismo , Receptores de Interleucina-10/antagonistas & inibidores , Anticorpos Bloqueadores/imunologia
10.
Growth Factors ; 41(3): 115-129, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37403648

RESUMO

Knee osteoarthritis (KOA) is a degenerative joint illness which leads to knee pain and functional limitation. In this study, we combined microfracture surgery with kartogenin (KGN), a small bioactive molecule used to promote the differentiation of mesenchymal stem cells (MSCs), and explored its impact on cartilage repair and possible latent mechanisms of action. The research offers a brand-new idea for the clinical cure of KOA. The microfracture technique in combination with KNG treatment was performed on a rabbit model of KOA. Animal behaviour was evaluated after the intra-articular injection of miR-708-5p and Special AT-rich sequence binding protein 2 (SATB2) lentiviruses. Later, the expression of the tumour necrosis factor α (TNF-α) and interleukin- 1 (IL-1), the pathology of synovial tissue and cartilage tissue, and the positive cartilage type II collagen, MMP-1, MMP-3 and TIMP-1 were detected. Finally, a luciferase assay was conducted to verify the interaction of miR-708-5p and SATB2. Our results showed that miR-708-5p was elevated in the rabbit KOA model; however, the expression of SATB2 was reduced. Meanwhile, the microfracture technology combined with MSCs inducer KGN drove cartilage repair and regeneration in rabbit KOA by repressing the miR-708-5p expression. We also found that miR-708-5p directly targeted the SATB2 mRNA to regulate its expression. Furthermore, our data urged that elevating miR-708-5p or restraining SATB2 may reverse the therapeutic effect of the microfracture technique combined with MSCs inducer on rabbit KOA. Microfracture technique combined with MSCs inducer represses miR-708-5p to target SATB2 to drive cartilage repair and regeneration in rabbit KOA. This indicates that the microfracture technique combined with MSCs inducers is supposed to be an effective latent method for osteoarthritis cure.


Assuntos
Fraturas de Estresse , Células-Tronco Mesenquimais , MicroRNAs , Osteoartrite do Joelho , Animais , Coelhos , Osteoartrite do Joelho/genética , Osteoartrite do Joelho/terapia , Osteoartrite do Joelho/metabolismo , Fraturas de Estresse/metabolismo , Cartilagem/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo
11.
Opt Express ; 31(8): 12150-12161, 2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-37157380

RESUMO

In this study, a modified interfering vortex phase mask (MIVPM) is proposed to generate a new type of self-rotating beam. The MIVPM is based on a conventional and stretched vortex phase for generating a self-rotating beam that rotates continuously with increasing propagation distances. A combined phase mask can produce multi-rotating array beams with controllable sub-region number. The combination method of this phase was analyzed in detail. This study proves that this self-rotating array beam has an effectively enhanced central lobe and reduced side lobe owing to adding a vortex phase mask compared with a conventional self-rotating beam. Furthermore, the propagation dynamics of this beam can be modulated by varying the topological charge and constant a. With an increase in the topological charge, the area crossed by the peak beam intensity along the propagation axis increases. Meanwhile, the novel self-rotating beam is used for optical manipulation under phase gradient force. The proposed self-rotating array beam has potential applications in optical manipulation and spatial localization.

12.
BMC Cancer ; 23(1): 416, 2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37158833

RESUMO

BACKGROUND: Pathologic complete response (pCR) following preoperative systemic therapy is associated with improved outcomes after subsequent liver transplant/resection in hepatocellular carcinoma (HCC). However, the relationship between radiographic and histopathological response remains unclear. METHODS: We retrospectively examined patients with initially unresectable HCC who received tyrosine kinase inhibitor (TKI) plus anti-programmed death 1 (PD-1) therapy before undergoing liver resection between March 2019 and September 2021 across 7 hospitals in China. Radiographic response was evaluated using mRECIST. A pCR was defined as no viable tumor cells in resected samples. RESULTS: We included 35 eligible patients, of whom 15 (42.9%) achieved pCR after systemic therapy. After a median follow-up of 13.2 months, tumors recurred in 8 non-pCR and 1 pCR patient. Before resection, there were 6 complete responses, 24 partial responses, 4 stable disease cases, and 1 progressive disease case, per mRECIST. Predicting pCR by radiographic response yielded an area under the receiver operating characteristic curve (AUC) of 0.727 (95% CI: 0.558-0.902), with an optimal cutoff value of 80% reduction in the enhanced area in MRI (called major radiographic response), which had a 66.7% sensitivity, 85.0% specificity, and a 77.1% diagnostic accuracy. When radiographic response was combined with α-fetoprotein response, the AUC was 0.926 (95% CI: 0.785-0.999); the optimal cutoff value was 0.446, which had a 91.7% sensitivity, 84.6%, specificity, and an 88.0% diagnostic accuracy. CONCLUSIONS: In patients with unresectable HCC receiving combined TKI/anti-PD 1 therapy, major radiographic response alone or combined with α-fetoprotein response may predict pCR.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/tratamento farmacológico , alfa-Fetoproteínas , Estudos Retrospectivos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/tratamento farmacológico , Recidiva Local de Neoplasia/diagnóstico por imagem , Imunoterapia , Inibidores de Proteínas Quinases/uso terapêutico
13.
J Synchrotron Radiat ; 29(Pt 2): 281-287, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35254289

RESUMO

Stable actinide colloids and nanoparticles are of interest because of their potential to affect the transportation of radionuclides in the near-field of a nuclear waste repository. At high concentrations, thorium(IV) can precipitate to form intrinsic colloids. In the present study, polynuclear thorium colloids and thorium dioxide crystallites, formed by the condensation of hydrolyzed Th4+ solutions (3 mM; initial pH 5.5) aged for up to 18 months, were studied using small-angle X-ray scattering. Scattering profiles were fitted using a unified Guinier/power-law model (Beaucage model) to extract the radii of gyration and Porod exponents. Analysis of the scattering profiles from a dispersion aged for 5 months indicated that both polymer coils and more compacted structures (radius of gyration Rg ≃ 10 nm) were present, which translated in the Kratky plots as a plateau and a peak maximum, respectively. After 18 months, the SAXS data were consistent with the presence of agglomerates of ThO2 particles suspended in aqueous solution (pH 3.2; [Th] = 1.45 mM). The measured radius of gyration (Rg) of the agglomerates was 5.8 nm, whereas the radius of the ThO2 particles was 2.5 nm.

14.
Bioorg Med Chem ; 71: 116951, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35973281

RESUMO

Using an in-cell AMPK activation assay, we have developed structure-activity relationships around a hit pyridine dicarboxamide 5 that resulted in 40 (R419). A particular focus was to retain the on-target potency while also improving microsomal stability and reducing off-target activities, including hERG inhibition. We were able to show that removing a tertiary amino group from the piperazine unit of hit compound 5 improved microsomal stability while hERG inhibition was improved by modifying the substitution of the central core pyridine ring. The SAR resulted in 40, which continues to maintain on-target potency. Compound 40 was able to activate AMPK in vivo after oral administration and showed efficacy in animal models investigating activation of AMPK as a therapy for glucose control (both db/db and DIO mouse models).


Assuntos
Proteínas Quinases Ativadas por AMP , Hipoglicemiantes , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Ativação Enzimática , Hipoglicemiantes/farmacologia , Camundongos , Piridinas , Relação Estrutura-Atividade
15.
Phys Chem Chem Phys ; 24(18): 11112-11123, 2022 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-35475436

RESUMO

Generally, the solution viscosity of wormlike micelles (WLMs) assembled from common surfactants decreases upon an increase in the temperature, following the Arrhenius law. However, abnormal thermo-thickening behavior has been repeatedly observed for WLMs formed by ultra-long-chain (≥C18) surfactants. It would be useful to unravel the mechanism behind this phenomenon. Here, three C22-tailed surfactants with an erucyl tail, two of them containing carboxylate or sulfonate head groups (UC22DAB and UC22DAS) and a cationic one with an iodide counterion (UC22DAI), and two C18-tailed betaines with olemido- and stearamidopropyl hydrophobic chains (UC18DAS and C18DAS) were characterised in terms of their viscosity and viscoelastic behavior with increasing temperature to examine the roles of head groups, tail length and tail nature. Their micellar structures were elucidated at various temperatures using small angle neutron scattering (SANS), small angle neutron X-ray scattering (SAXS) and molecular dynamics simulation. It is found that the thermo-thickening behavior of ultra-long-chain surfactants is ascribed to the prolonged persistence length and increased entanglement points. When the temperature is increased, an increase in viscosity is always accompanied by a longer persistent length, thus a larger hydrodynamic volume. The iceberg structure around the hydrophobic tail of surfactants can be destroyed at high temperatures leading to the self-assembly of these surfactants. In this self-assembly process, compared to cationic surfactants, zwitterionic surfactants can form WLMs more readily due to weak electrostatic repulsions between their head groups; the longer tails give the surfactants enhanced hydrophobicity to form WLMs with a long breaking time; the cis-unsaturation and the resulting kink in the hydrophobic tails give the surfactants good solubility, which is not conducive to the formation of micelles. In brief, the zwitterionic, longer tail and saturated tail surfactants can form WLMs with a prolonged persistence length at elevated temperatures.

16.
Acta Pharmacol Sin ; 43(9): 2373-2385, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35046516

RESUMO

The protein arginine methyltransferase 5 (PRMT5), which is highly expressed in tumour tissues, plays a crucial role in cancer development. However, the mechanism by which PRMT5 promotes cancer growth is poorly understood. Here, we report that PRMT5 contributes to lipid metabolism reprogramming, tumour growth and metastasis depending on the SIRT7-mediated desuccinylation of PRMT5 K387 in tumours. Mass spectrometric analysis identified PRMT5 lysine 387 as its succinylation site. Moreover, the desuccinylation of PRMT5 K387 enhances the methyltransferase activity of PRMT5. SIRT7 catalyses the desuccinylation of PRMT5 in cells. The SIRT7-mediated dessuccinylation of PRMT5 lysine 387 fails to bind to STUB1, decreasing PRMT5 ubiquitination and increasing the interaction between PRMT5 and Mep50, which promotes the formation of the PRMT5-Mep50 octamer. The PRMT5-Mep50 octamer increases PRMT5 methyltransferase activity, leading to arginine methylation of SREBP1a. The symmetric dimethylation of SREBP1a increases the levels of cholesterol, fatty acid, and triglyceride biogenesis in the cells, escaping degradation through the ubiquitin-proteasome pathway. Functionally, the desuccinylation of PRMT5 K387 promotes lipid metabolism reprogramming, tumour growth and metastasis in vitro and in vivo in tumours.


Assuntos
Neoplasias , Sirtuínas , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Humanos , Metabolismo dos Lipídeos , Lisina , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Sirtuínas/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
17.
J Am Chem Soc ; 143(6): 2484-2490, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33538597

RESUMO

Intercatalyst coupling has been widely applied in the functional mimics for binuclear synergy in natural metal enzymes. Herein, we introduce two facile and effective design strategies, which facilitate the coupling of two catalytic units via electrostatic interactions. The first system is based on a catalyst molecule functionalized with both a positively charged and a negatively charged group in the structure being able to pair with each other in an antiparallel manner arranged by electrostatic interactions. The other system consists of a mixture of two different of catalysts modified with either positively or negatively charged groups to generate intermolecular electrostatic interactions. Applying these designs to Ru(bda) (H2bda = 2,2'-bipyridine-6,6'-dicarboxylic acid) water-oxidation catalysts improved the catalytic performance by more than an order of magnitude. The intermolecular electrostatic interactions in these two systems were fully identified by 1H NMR, TEM, SAXS, and electrical conductivity experiments. Molecular dynamics simulations further verified that electrostatic interactions contribute to the formation of prereactive dimers, which were found to play a key role in dramatically improving the catalytic performance. The successful strategies demonstrated here can be used in designing other intercatalyst coupling systems for activation and formation of small molecules and organic synthesis.

18.
Small ; 17(49): e2103224, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34611983

RESUMO

Photocatalysis offers a sustainable strategy for hydrogen peroxide (H2 O2 ) production, which is an essential oxidant and emerging energy carrier in modern chemical industry. The development of polymer-based photocatalysts to produce H2 O2 has great potential but is limited by lower efficiency due to the limitation of light utilization and the low charge separation efficiency. Herein, a series of monodispersed mesoporous resorcinol-formaldehyde resin spheres (MRFS) are reported with a rational designed spatial charge distribution, exhibiting wide light absorption with a solar-to-chemical conversion (SCC) efficiency of 1.1%. Surface photovoltage microscopy (SPVM) measurements unraveled the charge separation in nanospace with uneven distribution of donor (D) and acceptor (A) sites. A density functional theory (DFT) calculation elucidated the origin of photogenerated electrons and holes. Moreover, MRFS demonstrates photocatalytic water oxidation ability. The findings in this work open a new avenue for the development of porous polymeric photocatalysts toward highly efficient solar energy conversion.

19.
Blood ; 133(5): 457-469, 2019 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-30530752

RESUMO

Erythropoiesis is the complex, dynamic, and tightly regulated process that generates all mature red blood cells. To understand this process, we mapped the developmental trajectories of progenitors from wild-type, erythropoietin-treated, and Flvcr1-deleted mice at single-cell resolution. Importantly, we linked the quantity of each cell's surface proteins to its total transcriptome, which is a novel method. Deletion of Flvcr1 results in high levels of intracellular heme, allowing us to identify heme-regulated circuitry. Our studies demonstrate that in early erythroid cells (CD71+Ter119neg-lo), heme increases ribosomal protein transcripts, suggesting that heme, in addition to upregulating globin transcription and translation, guarantees ample ribosomes for globin synthesis. In later erythroid cells (CD71+Ter119lo-hi), heme decreases GATA1, GATA1-target gene, and mitotic spindle gene expression. These changes occur quickly. For example, in confirmatory studies using human marrow erythroid cells, ribosomal protein transcripts and proteins increase, and GATA1 transcript and protein decrease, within 15 to 30 minutes of amplifying endogenous heme synthesis with aminolevulinic acid. Because GATA1 initiates heme synthesis, GATA1 and heme together direct red cell maturation, and heme stops GATA1 synthesis, our observations reveal a GATA1-heme autoregulatory loop and implicate GATA1 and heme as the comaster regulators of the normal erythroid differentiation program. In addition, as excessive heme could amplify ribosomal protein imbalance, prematurely lower GATA1, and impede mitosis, these data may help explain the ineffective (early termination of) erythropoiesis in Diamond Blackfan anemia and del(5q) myelodysplasia, disorders with excessive heme in colony-forming unit-erythroid/proerythroblasts, explain why these anemias are macrocytic, and show why children with GATA1 mutations have DBA-like clinical phenotypes.


Assuntos
Células Precursoras Eritroides/citologia , Eritropoese , Fator de Transcrição GATA1/metabolismo , Heme/metabolismo , Adulto , Anemia de Diamond-Blackfan/genética , Anemia de Diamond-Blackfan/metabolismo , Animais , Vias Biossintéticas , Células Cultivadas , Células Precursoras Eritroides/metabolismo , Fator de Transcrição GATA1/genética , Deleção de Genes , Regulação da Expressão Gênica , Humanos , Proteínas de Membrana Transportadoras/genética , Camundongos , Receptores Virais/genética , Análise de Célula Única , Transcriptoma
20.
Eur Radiol ; 31(1): 447-457, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32700020

RESUMO

OBJECTIVES: Accurately predicting the WHO classification of thymomas is urgently needed to optimize individualized therapeutic strategies. We aimed to develop and validate a combined radiomics nomogram for personalized prediction of histologic subtypes in patients with thymomas. METHODS: A total of 182 thymoma patients were divided into training (n = 128) and test (n = 54) cohorts. Radiomics features were extracted from T2-weighted, T2-weighted fat suppression, and diffusion-weighted images to establish a radiomics signature in the training cohort. Multivariate logistic regression analysis was used to develop a combined radiomics nomogram that incorporated clinical, conventional MR imaging variables, apparent diffusion coefficient (ADC) value, and radiomics signature. The efficacy of clinical, conventional MR imaging, or ADC model was also evaluated respectively. The performances of different models were compared by receiver operating characteristic analysis and Delong test. The discrimination, calibration, and clinical usefulness of the combined radiomics nomogram were assessed. RESULTS: The radiomics signature, consisting of 14 features, achieved favorable predictive efficacy in differentiating low-risk from high-risk thymomas, outperforming clinical, conventional MR imaging, and ADC models. The combined radiomics nomogram incorporating tumor shape, ADC value, and radiomics signature yielded the best performance (training cohort: area under the curve [AUC] = 0.946, test cohort: AUC = 0.878). The calibration curve and decision curve analysis indicated the clinical utility of the combined radiomics nomogram. CONCLUSIONS: The radiomics signature is a useful tool that can be used to predict histologic subtypes of thymomas. The combined radiomics nomogram improved the individualized subtype prediction in patients with thymomas. KEY POINTS: • Fourteen robust features were selected to develop a radiomics signature for preoperative prediction of thymoma subtype. • MRI-based radiomics signature can differentiate low-risk thymomas from high-risk thymomas with favorable predictive efficacy compared with clinical, conventional MR imaging, and ADC models. • Combined radiomics nomogram based on tumor shape, ADC value, and radiomics signature could improve the individualized subtype prediction in patients with thymomas.


Assuntos
Timoma , Neoplasias do Timo , Humanos , Imageamento por Ressonância Magnética , Nomogramas , Estudos Retrospectivos , Timoma/diagnóstico por imagem , Neoplasias do Timo/diagnóstico por imagem
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