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1.
J Chem Inf Model ; 64(8): 3386-3399, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38489841

RESUMO

Aggregation of tau protein into intracellular fibrillary inclusions is characterized as the hallmark of tauopathies, including Alzheimer's disease and chronic traumatic encephalopathy. The microtubule-binding (MTB) domain of tau, containing either three or four repeats with sequence similarities, plays an important role in determining tau's aggregation. Previous studies have reported that abnormal acetylation of lysine residues displays a distinct effect on the formation of pathological tau aggregates. However, the underlying molecular mechanism remains mostly elusive. In this study, we performed extensive replica exchange molecular dynamics (REMD) simulations of 144 µs in total to systematically investigate the dimerization of four tau MTB repeats and explore the impacts of Lys280 (K280) or Lys321 (K321) acetylation on the conformational ensembles of the R2 or R3 dimer. Our results show that R3 is the most prone to aggregation among the four repeats, followed by R2 and R4, while R1 displays the weakest aggregation propensity with a disordered structure. Acetylation of K280 could promote the aggregation of R2 peptides by increasing the formation of ß-sheet structures and strengthening the interchain interaction. However, K321 acetylation decreases the ß-sheet content of the R3 dimer, reduces the ability of R3 peptides to form long ß-strands, and promotes the stable helix structure formation. The salt bridge and Y310-Y310 π-π stacking interactions of the R3 dimer are greatly weakened by K321 acetylation, resulting in the inhibition of dimerization. This study uncovers the structural ensembles of tau MTB repeats and provides mechanistic insights into the influences of acetylation on tau aggregation, which may deepen the understanding of the pathogenesis of tauopathies.


Assuntos
Microtúbulos , Simulação de Dinâmica Molecular , Agregados Proteicos , Proteínas tau , Proteínas tau/metabolismo , Proteínas tau/química , Acetilação , Microtúbulos/metabolismo , Multimerização Proteica , Ligação Proteica , Humanos , Conformação Proteica
2.
Planta ; 258(2): 24, 2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37344696

RESUMO

MAIN CONCLUSION: OsFAR1 encodes a fatty acyl-CoA reductase involved in biosynthesis of primary alcohols and plays an important role in drought stress response in rice. Cuticular waxes cover the outermost surface of terrestrial plants and contribute to inhibiting nonstomatal water loss and improving plant drought resistance. Primary alcohols are the most abundant components in the leaf cuticular waxes of rice (Oryza sativa), but the biosynthesis and regulation of primary alcohol remain largely unknown in rice. Here, we identified and characterized an OsFAR1 gene belonging to the fatty acyl-CoA reductases (FARs) via a homology-based approach in rice. OsFAR1 was activated by abiotic stresses and abscisic acid, resulting in increased production of primary alcohol in rice. Heterologous expression of OsFAR1 enhanced the amounts of C22:0 and C24:0 primary alcohols in yeast (Saccharomyces cerevisiae) and C24:0 to C32:0 primary alcohols in Arabidopsis. Similarly, OsFAR1 overexpression significantly increased the content of C24:0 to C30:0 primary alcohols on rice leaves. Finally, OsFAR1 overexpression lines exhibited reduced cuticle permeability and enhanced drought tolerance in rice and Arabidopsis. Taken together, our results demonstrate that OsFAR1 is involved in rice primary alcohol biosynthesis and plays an important role in responding to drought and other environmental stresses.


Assuntos
Arabidopsis , Oryza , Oryza/genética , Oryza/metabolismo , Resistência à Seca , Arabidopsis/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Álcoois/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Secas , Álcoois Graxos/metabolismo , Ceras/metabolismo , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas/metabolismo
3.
Int J Mol Sci ; 24(5)2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36902127

RESUMO

The use of mesenchymal stem cells (MSCs) has become a new strategy for treating diabetic kidney disease (DKD). However, the role of placenta derived mesenchymal stem cells (P-MSCs) in DKD remains unclear. This study aims to investigate the therapeutic application and molecular mechanism of P-MSCs on DKD from the perspective of podocyte injury and PINK1/Parkin-mediated mitophagy at the animal, cellular, and molecular levels. Western blotting, reverse transcription polymerase chain reaction, immunofluorescence, and immunohistochemistry were used to detect the expression of podocyte injury-related markers and mitophagy-related markers, SIRT1, PGC-1α, and TFAM. Knockdown, overexpression, and rescue experiments were performed to verify the underlying mechanism of P-MSCs in DKD. Mitochondrial function was detected by flow cytometry. The structure of autophagosomes and mitochondria were observed by electron microscopy. Furthermore, we constructed a streptozotocin-induced DKD rat model and injected P-MSCs into DKD rats. Results showed that as compared with the control group, exposing podocytes to high-glucose conditions aggravated podocyte injury, represented by a decreased expression of Podocin along with increased expression of Desmin, and inhibited PINK1/Parkin-mediated mitophagy, manifested as a decreased expression of Beclin1, the LC3II/LC3I ratio, Parkin, and PINK1 associated with an increased expression of P62. Importantly, these indicators were reversed by P-MSCs. In addition, P-MSCs protected the structure and function of autophagosomes and mitochondria. P-MSCs increased mitochondrial membrane potential and ATP content and decreased the accumulation of reactive oxygen species. Mechanistically, P-MSCs alleviated podocyte injury and mitophagy inhibition by enhancing the expression of the SIRT1-PGC-1α-TFAM pathway. Finally, we injected P-MSCs into streptozotocin-induced DKD rats. The results revealed that the application of P-MSCs largely reversed the markers related to podocyte injury and mitophagy and significantly increased the expression of SIRT1, PGC-1α, and TFAM compared with the DKD group. In conclusion, P-MSCs ameliorated podocyte injury and PINK1/Parkin-mediated mitophagy inhibition in DKD by activating the SIRT1-PGC-1α-TFAM pathway.


Assuntos
Nefropatias Diabéticas , Células-Tronco Mesenquimais , Podócitos , Animais , Feminino , Gravidez , Ratos , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Células-Tronco Mesenquimais/metabolismo , Mitofagia , Placenta/citologia , Placenta/metabolismo , Podócitos/metabolismo , Podócitos/patologia , Proteínas Quinases/metabolismo , Sirtuína 1/metabolismo , Estreptozocina , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
4.
Int J Mol Sci ; 24(18)2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37762268

RESUMO

Multiprotein bridging factor 1 (MBF1) is an ancient family of transcription coactivators that play a crucial role in the response of plants to abiotic stress. In this study, we analyzed the genomic data of five Solanaceae plants and identified a total of 21 MBF1 genes. The expansion of MBF1a and MBF1b subfamilies was attributed to whole-genome duplication (WGD), and the expansion of the MBF1c subfamily occurred through transposed duplication (TRD). Collinearity analysis within Solanaceae species revealed collinearity between members of the MBF1a and MBF1b subfamilies, whereas the MBF1c subfamily showed relative independence. The gene expression of SlER24 was induced by sodium chloride (NaCl), polyethylene glycol (PEG), ABA (abscisic acid), and ethrel treatments, with the highest expression observed under NaCl treatment. The overexpression of SlER24 significantly enhanced the salt tolerance of tomato, and the functional deficiency of SlER24 decreased the tolerance of tomato to salt stress. SlER24 enhanced antioxidant enzyme activity to reduce the accumulation of reactive oxygen species (ROS) and alleviated plasma membrane damage under salt stress. SlER24 upregulated the expression levels of salt stress-related genes to enhance salt tolerance in tomato. In conclusion, this study provides basic information for the study of the MBF1 family of Solanaceae under abiotic stress, as well as a reference for the study of other plants.


Assuntos
Proteínas de Plantas , Estresse Salino , Solanaceae , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Estresse Salino/genética , Cloreto de Sódio/farmacologia , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Solanaceae/genética , Solanaceae/fisiologia
5.
Lancet ; 395(10229): 1054-1062, 2020 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-32171076

RESUMO

BACKGROUND: Since December, 2019, Wuhan, China, has experienced an outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epidemiological and clinical characteristics of patients with COVID-19 have been reported but risk factors for mortality and a detailed clinical course of illness, including viral shedding, have not been well described. METHODS: In this retrospective, multicentre cohort study, we included all adult inpatients (≥18 years old) with laboratory-confirmed COVID-19 from Jinyintan Hospital and Wuhan Pulmonary Hospital (Wuhan, China) who had been discharged or had died by Jan 31, 2020. Demographic, clinical, treatment, and laboratory data, including serial samples for viral RNA detection, were extracted from electronic medical records and compared between survivors and non-survivors. We used univariable and multivariable logistic regression methods to explore the risk factors associated with in-hospital death. FINDINGS: 191 patients (135 from Jinyintan Hospital and 56 from Wuhan Pulmonary Hospital) were included in this study, of whom 137 were discharged and 54 died in hospital. 91 (48%) patients had a comorbidity, with hypertension being the most common (58 [30%] patients), followed by diabetes (36 [19%] patients) and coronary heart disease (15 [8%] patients). Multivariable regression showed increasing odds of in-hospital death associated with older age (odds ratio 1·10, 95% CI 1·03-1·17, per year increase; p=0·0043), higher Sequential Organ Failure Assessment (SOFA) score (5·65, 2·61-12·23; p<0·0001), and d-dimer greater than 1 µg/mL (18·42, 2·64-128·55; p=0·0033) on admission. Median duration of viral shedding was 20·0 days (IQR 17·0-24·0) in survivors, but SARS-CoV-2 was detectable until death in non-survivors. The longest observed duration of viral shedding in survivors was 37 days. INTERPRETATION: The potential risk factors of older age, high SOFA score, and d-dimer greater than 1 µg/mL could help clinicians to identify patients with poor prognosis at an early stage. Prolonged viral shedding provides the rationale for a strategy of isolation of infected patients and optimal antiviral interventions in the future. FUNDING: Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences; National Science Grant for Distinguished Young Scholars; National Key Research and Development Program of China; The Beijing Science and Technology Project; and Major Projects of National Science and Technology on New Drug Creation and Development.


Assuntos
Infecções por Coronavirus/mortalidade , Escores de Disfunção Orgânica , Planejamento de Assistência ao Paciente , Pneumonia Viral/mortalidade , Medição de Risco , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Betacoronavirus , COVID-19 , Teste para COVID-19 , Doenças Cardiovasculares/complicações , China , Técnicas de Laboratório Clínico , Estudos de Coortes , Comorbidade , Infecções por Coronavirus/complicações , Infecções por Coronavirus/diagnóstico , Complicações do Diabetes , Progressão da Doença , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/análise , Humanos , Hipertensão/complicações , Masculino , Pessoa de Meia-Idade , Mortalidade/tendências , Pandemias , Isolamento de Pacientes , Pneumonia Viral/complicações , Pneumonia Viral/diagnóstico , Prognóstico , Estudos Retrospectivos , Medição de Risco/métodos , Fatores de Risco , SARS-CoV-2 , Adulto Jovem
6.
J Cell Mol Med ; 22(10): 4751-4759, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30006956

RESUMO

Long non-coding RNAs (lncRNAs) have been illustrated to function as important regulators in carcinogenesis and cancer progression. However, the roles of lncRNA NNT-AS1 in gastric cancer remain unclear. In the present study, we investigate the biological role of NNT-AS1 in gastric cancer tumorigenesis. Results revealed that NNT-AS1 expression level was significantly up-regulated in GC tissue and cell lines compared with adjacent normal tissue and normal cell lines. The ectopic overexpression of NNT-AS1 indicated the poor prognosis of GC patients. In vitro experiments validated that NNT-AS1 knockdown suppressed the proliferation and invasion ability and induced the GC cell cycle progression arrest at G0/G1 phase. In vivo xenograft assay, NNT-AS1 silencing decreased the tumour growth of GC cells. Bioinformatics online program predicted that miR-424 targeted the 3'-UTR of NNT-AS1. Luciferase reporter assay, RNA-immunoprecipitation (RIP) and RNA pull-down assay validated the molecular binding within NNT-AS1 and miR-424, therefore jointly forming the RNA-induced silencing complex (RISC). Moreover, E2F1 was verified to act as the target gene of NNT-AS1/miR-424, indicating the NNT-AS1/miR-424/E2F1 axis. In conclusion, our study indicates that NNT-AS1 sponges miR-424/E2F1 to facilitate GC tumorigenesis and cycle progress, revealing the oncogenic role of NNT-AS1 for GC.


Assuntos
Fator de Transcrição E2F1/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , RNA Longo não Codificante/genética , Complexo de Inativação Induzido por RNA/genética , Neoplasias Gástricas/genética , Regiões 3' não Traduzidas , Idoso , Animais , Sequência de Bases , Carcinogênese/genética , Carcinogênese/metabolismo , Carcinogênese/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Fator de Transcrição E2F1/metabolismo , Feminino , Humanos , Metástase Linfática , Masculino , Camundongos , Camundongos Nus , MicroRNAs/metabolismo , Pessoa de Meia-Idade , Oligorribonucleotídeos/genética , Oligorribonucleotídeos/metabolismo , RNA Longo não Codificante/antagonistas & inibidores , RNA Longo não Codificante/metabolismo , Complexo de Inativação Induzido por RNA/metabolismo , Fase de Repouso do Ciclo Celular/genética , Transdução de Sinais , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologia , Análise de Sobrevida , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Appl Opt ; 55(23): 6447-51, 2016 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-27534493

RESUMO

In this paper, a vector ray tracing (VRT) model is used to simulate optical caustic structures, including rainbow and hyperbolic umbilic (HU) fringes, in the tertiary rainbow region of light scattering from oblate spheroidal droplets. In order to apply the optical caustic structures to particle diagnostics, the evolution of rainbow and HU fringes with an increase in the aspect ratio of oblate spheroidal droplets is investigated in detail, and the curvature of rainbow fringes are calculated. Next, on the basis of the VRT model, the location of cusp caustics is calculated and compared with theoretical prediction.

8.
Front Immunol ; 15: 1342641, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38803498

RESUMO

The possible protective effect of interleukin-32 (IL-32) in Mycobacterium tuberculosis (Mtb) infection has been indicated. However, few studies have been focused on IL-32 in tuberculosis patients. Additionally, the regulation of IL-32 production has rarely been reported. In the present study, the production, regulation, and role of IL-32 in tuberculous pleurisy (TBP) were investigated. We found that the content of IL-32 in tuberculous pleural effusion (TPE) was higher than the level in the malignant pleural effusion and transudative pleural effusion. The level of IL-32 mRNA in pleural fluid mononuclear cells (PFMCs) was higher than that in peripheral blood mononuclear cells (PBMCs) of patients with TBP, and this difference was mainly reflected in the splice variants of IL-32α, IL-32ß, and IL-32γ. Compared with the PBMCs, PFMCs featured higher IL-32ß/IL-32γ and IL-32α/IL-32γ ratios. In addition, lipopolysaccharide (LPS), Bacillus Calmette-Guérin (BCG), and H37Ra stimulation could induce IL-32 production in the PFMCs. IL-32 production was positively correlated with the TNF-α, IFN-γ, and IL-1Ra levels in TPE, whereas IFN-γ, but not TNF-α or IL-1Ra, could induce the production of IL-32 in PFMCs. Furthermore, IL-32γ could induce the TNF-α production in PFMCs. Monocytes and macrophages were the main sources of IL-32 in PFMCs. Nevertheless, direct cell-cell contact between lymphocytes and monocytes/macrophages plays an important role in enhancing IL-32 production by monocyte/macrophage cells. Finally, compared with the non-tuberculous pleural effusion, the purified CD4+ and CD8+ T cells in TPE expressed higher levels of intracellular IL-32. Our results suggested that, as a potential biomarker, IL-32 may play an essential role in the protection against Mtb infection in patients with TBP. However, further studies need to be carried out to clarify the functions and mechanisms of the IFN-γ/IL-32/TNF-α axis in patients with TBP.


Assuntos
Interleucinas , Derrame Pleural , Tuberculose Pleural , Humanos , Interleucinas/metabolismo , Interleucinas/imunologia , Tuberculose Pleural/imunologia , Tuberculose Pleural/metabolismo , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Derrame Pleural/imunologia , Derrame Pleural/metabolismo , Derrame Pleural/microbiologia , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Mycobacterium tuberculosis/imunologia , Idoso , Interferon gama/metabolismo
9.
Front Mol Biosci ; 11: 1158852, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38693916

RESUMO

Regulator of G-protein signaling (RGS) proteins are regulators of signal transduction mediated by G protein-coupled receptors (GPCRs). Current studies have shown that some molecules in the RGS gene family are related to the occurrence, development and poor prognosis of malignant tumors. However, the RGS gene family has been rarely studied in gastric cancer. In this study, we explored the mutation and expression profile of RGS gene family in gastric cancer, and evaluated the prognostic value of RGS expression. Then we established a prognostic model based on RGS gene family and performed functional analysis. Further studies showed that RGS4, as an independent prognostic predictor, may play an important role in regulating fibroblasts in the immune microenvironment. In conclusion, this study explores the value of RGS gene family in gastric cancer, which is of great significance for predicting the prognosis and guiding the treatment of gastric cancer.

10.
Biophys Chem ; 312: 107283, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38941873

RESUMO

The serotonin receptor subtype 1A (5-HT1AR), one of the G-protein-coupled receptor (GPCR) family, has been implicated in several neurological conditions. Understanding the activation and inactivation mechanism of 5-HT1AR at the molecular level is critical for discovering novel therapeutics in many diseases. Recently there has been a growing appreciation for the role of external electric fields (EFs) in influencing the structure and activity of biomolecules. In this study, we used molecular dynamics (MD) simulations to examine conformational features of active states of 5-HT1AR and investigate the effect of an external static EF with 0.02 V/nm applied on the active state of 5-HT1AR. Our results showed that the active state of 5-HT1AR maintained the native structure, while the EF led to structural modifications in 5-HT1AR, particularly inducing the inward movement of transmembrane helix 6 (TM6). Furthermore, it disturbed the conformational switches associated with activation in the CWxP, DRY, PIF, and NPxxY motifs, consequently predisposing an inclination towards the inactive-like conformation. We also found that the EF led to an overall increase in the dipole moment of 5-HT1AR, encompassing TM6 and pivotal amino acids. The analyses of conformational properties of TM6 showed that the changed secondary structure and decreased solvent exposure occurred upon the EF condition. The interaction of 5-HT1AR with the membrane lipid bilayer was also altered under the EF. Our findings reveal the molecular mechanism underlying the transition of 5-HT1AR conformation induced by external EFs, which offer potential novel insights into the prospect of employing structure-based EF applications for GPCRs.

11.
Front Neurol ; 15: 1294125, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38390592

RESUMO

Background: The study of chronic traumatic encephalopathy (CTE) has received great attention from academia and the general public. This study aims to analyze the research productivity on CTE and investigate the most discussed articles in academia and the general public by conducting bibliometric and altmetric analyses. Methods: Data of articles were obtained from the Web of Science Core Databases and Altmetric Explore. VOSviewer and CiteSpace software were used to analyze and visualize the articles. The correlation between Altmetric attention scores (AAS) and citation counts were assessed by Spearman correlation coefficient. Results: 788 publications of CTE were eventually gathered and analyzed, and 100 articles with highest citation counts (Top-cited) and 100 articles with highest AASs (Top-AAS) were then identified. The keywords density map showed both the general public and the scientists were particularly interested in the risk factors and pathology of CTE, and scientists were interested in the causes and characteristics of neurodegenerative diseases while the public became increasingly concerned about the detection and prevention of CTE. By examining the shared characteristics of the 44 articles (High-High articles) that overlapped between Top-cited and Top-AAS articles, we identified certain traits that may potentially contribute to their high citation rates and high AASs. Besides, significant positive correlations with varied strength between AAS and citation were observed in the 788 articles, Top-cited, Top-AAS and High-High datasets. Conclusion: This study is the first to link bibliometric and altmetric analyses for CTE publications, which may provide deeper understanding of the attention of the scientists and the general public pay to the study of CTE, and offer some guidance and inspiration for future CTE in the selection of research topics and directions.

12.
Heliyon ; 10(5): e27576, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38463838

RESUMO

Objectives: Recently, there has been extensive research on dual immunotherapy for advanced or metastatic non-small cell lung cancer (NSCLC), yet a comprehensive evaluation is lacking. This study aimed to rank the available treatment options and assess the efficacy and safety of dual immunotherapy regimens through the implementation of a Bayesian network meta-analysis (NMA). Materials and methods: A thorough search was conducted to recognize eligible randomized controlled trials (RCTs) on March 20, 2023. Overall survival (OS), progression-free survival (PFS), treatment-related adverse events (TRAEs) and grade ≥3 TRAEs were evaluated to identify the efficacy and safety of dual immunotherapy regimens. The surface under the cumulative ranking curve (SUCRA) and P score were employed to rank the treatments. Results: Eleven clinical trials involving six different regimens were included in this study. The combination of anti-programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) antibodies with anti-T-cell immunoglobulin and ITIM domain (TIGIT) antibodies emerged as the most promising regimen for improving OS and PFS, followed by anti-PD-1/PD-L1 + anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) + chemotherapy treatment and anti-PD-1/PD-L1 + anti-CTLA-4 treatment. The forest plots demonstrated that these three regimens were all superior to chemotherapy. The above results were observed in both unselected treatment line and first-line settings. The least likely to be associated with TRAEs and grade ≥3 TRAEs were respectively anti-CTLA-4 treatment and anti-PD-1/PD-L1 + anti-TIGIT treatment, with anti-PD-1/PD-L1 + anti-CTLA-4 + chemotherapy treatment to be the worst. Conclusions: This NMA validated the promising efficacy and safety of dual immunotherapy in advanced or metastatic NSCLC. Among them, anti-PD-1/PD-L1 + anti-TIGIT regimen emerges as a highly potential therapeutic approach. Ongoing research efforts should focus on improving treatment regimens, identifying biomarkers, and managing TRAEs to optimize the patient benefits of dual immunotherapy.

13.
J Phys Chem B ; 127(1): 335-345, 2023 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-36594671

RESUMO

Abnormal aggregation of the microtubule-associated protein tau into intracellular fibrillary inclusions is characterized as the hallmark of tauopathies, including Alzheimer's disease and chronic traumatic encephalopathy. The hexapeptide 306VQIVYK311 (PHF6) of R3 plays an important role in the aggregation of tau. Recent experimental studies reported that phosphorylation of residue tyrosine 310 (Y310) could decrease the propensity of PHF6 to form fibrils and inhibit tau aggregation. However, the underlying inhibitory mechanism is not well understood. In this work, we systematically investigated the influences of phosphorylation on the conformational ensembles and oligomerization dynamics of PHF6 by performing extensive all-atom molecular dynamics (MD) simulations. Our replica exchange MD simulations demonstrate that Y310 phosphorylation could effectively suppress the formation of ß-structure and shift PHF6 oligomers toward coil-rich aggregates. The interaction analyses show that hydrogen bonding and hydrophobic interactions among PHF6 peptides, as well as Y310-Y310 π-π stacking and I308-Y310 CH-π interactions, are weakened by phosphorylation. Additional microsecond MD simulations show that Y310 phosphorylation could inhibit the oligomerization of PHF6 by preventing the formation of large ß-sheet oligomers and multi-layer ß-sheet aggregates. This study provides mechanistic insights into the phosphorylation-inhibited tau aggregation, which may be helpful for the in-depth understanding of the pathogenesis of tauopathies.


Assuntos
Doença de Alzheimer , Proteínas tau , Humanos , Fosforilação , Proteínas tau/química , Doença de Alzheimer/metabolismo , Peptídeos/metabolismo , Simulação de Dinâmica Molecular , Conformação Proteica em Folha beta , Proteínas Repressoras/metabolismo
14.
ACS Chem Neurosci ; 14(17): 3265-3277, 2023 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-37585669

RESUMO

The formation of neurofibrillary tangles by abnormal aggregation of tau protein is considered to be an important pathological characteristic of tauopathies, including Alzheimer's disease and chronic traumatic encephalopathy. Two hexapeptides 275VQIINK280 and 306VQIVYK311 in the microtubule binding region, named PHF6* and PHF6, are known to be aggregation-prone and responsible for tau fibrillization. Previous experiments reported that naphthoquinone-dopamine (NQDA) could effectively inhibit the aggregation of PHF6* and PHF6 and disrupt the fibrillar aggregates into nontoxic species, displaying a dual effect on the amyloid aggregation. However, the underlying molecular mechanism remains mostly elusive. Herein, we performed all-atom molecular dynamics (MD) simulations for 114 µs in total to systematically investigate the impacts of NQDA on the oligomerization of PHF6* and PHF6. The conformational ensembles of PHF6* and PHF6 peptides generated by replica exchange MD simulations show that NQDA could effectively prevent the hydrogen bond formation, reduce the ability of peptides to self-assemble into long ß-strand and large ß-sheets, and induce peptides to form a loosely packed and coil-rich oligomer. The interaction analysis shows that the binding of NQDA to PHF6* is mainly through hydrophobic interactions with residue I277 and hydrogen bonding interactions with Q276; for the PHF6 peptides, NQDA displays a strong π-π stacking interaction with residue Y310, thus impeding the Y310-Y310 π-π stacking and I308-Y310 CH-π interactions. The DA group of NQDA displays a stronger cation-π interaction than the NQ group, while the NQ group exhibits a stronger π-π stacking interaction. MD simulations demonstrate that NQDA prevents the conformational conversion to ß-sheet-rich aggregates and displays an inhibitory effect on the oligomerization dynamics of PHF6* and PHF6. Our results provide a complete picture of inhibitory mechanisms of NQDA on PHF6* and PHF6 oligomerization, which may pave the way for designing drug candidates for the treatment of tauopathies.


Assuntos
Doença de Alzheimer , Naftoquinonas , Humanos , Proteínas tau/metabolismo , Dopamina , Doença de Alzheimer/metabolismo , Peptídeos/uso terapêutico , Simulação de Dinâmica Molecular , Proteínas Repressoras/metabolismo
15.
J Inflamm Res ; 16: 1443-1455, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37042015

RESUMO

Purpose: Neoadjuvant immunochemotherapy (nICT) for resectable locally advanced esophageal squamous cell carcinoma (LA-ESCC) has attracted widespread attention recently, whose safety and clinical benefit was observed in clinical researches. This study aimed to develop and validate a novel predictor systemic inflammation-tumor markers index (SITI) to predict the pathological complete response (pCR) for resectable LA-ESCC patients receiving nICT. Patients and Methods: A total of 147 LA-ESCC patients who underwent nICT followed by surgery from February 2020 to April 2022 were included in the study. The dynamic change of inflammatory indexes was compared at baseline, after two cycles of nICT and postoperative one month. Least absolute shrinkage and selection operator (LASSO) regression was performed to avoid collinearity and identify key indexes, with SITI constructed. After univariate and multivariate stepwise forward logistic analyses, a nomogram for pCR prediction was developed. Results: 41(27.9%) patients achieved pCR among 147 resectable LA-ESCC patients received nICT. Compared with baseline, most inflammatory indexes were significantly decreased at postoperative one month. 5 key indexes were identified and then a predictive index named SITI was constructed. The result showed that lower SITI and earlier clinical tumor node metastasis (cTNM) stage were more likely to achieve pCR. The nomogram for pCR prediction had excellent discrimination performance (C-index = 0.791). Conclusion: The SITI is an independent predictor for pCR in resectable LA-ESCC patients received nICT. To our knowledge, our nomogram is the first model using systemic inflammation-tumor markers for pCR prediction and may be a promising predictor to effectively differentiate pCR for nICT in LA-ESCC patients.

16.
Plants (Basel) ; 12(16)2023 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-37631208

RESUMO

Purple-grained wheat (Triticum aestivum L.) is an important germplasm source in crop breeding. Anthocyanin biosynthesis in the pericarps of purple-grained wheat is largely light-dependent; however, the regulatory mechanisms underlying light-induced anthocyanin accumulation in the wheat pericarp remain unknown. Here we determined that anthocyanins rapidly accumulate in the pericarps of the purple-grained wheat cultivar Heixiaomai 76 (H76) at 16 days after pollination under light treatment. Using transcriptome sequencing, differential gene expression analysis, and phylogenetic analysis, we identified two key genes involved in light signaling in wheat: ELONGATED HYPOCOTYL 5-7A (TaHY5-7A) and B-BOX-3B (TaBBX-3B). TaHY5-7A and TaBBX-3B were highly expressed in purple-grained wheat pericarps. The heterologous expression of TaHY5-7A partially restored the phenotype of the Arabidopsis (Arabidopsis thaliana) hy5 mutant, resulting in increased anthocyanin accumulation and a shortened hypocotyl. The heterologous expression of TaBBX-3B in wild-type Arabidopsis had similar effects. TaHY5-7A and TaBBX-3B were nucleus-localized, consistent with a function in transcription regulation. However, TaHY5-7A, which lacks a transactivation domain, was not sufficient to activate the expression of PURPLE PERICARP-MYB 1 (TaPpm1), the key anthocyanin biosynthesis regulator in purple pericarps of wheat. TaHY5-7A physically interacted with TaBBX-3B in yeast two-hybrid and bimolecular fluorescence complementation assays. Additionally, TaHY5-7A, together with TaBBX-3B, greatly enhanced the promoter activity of TaPpm1 in a dual luciferase assay. Overall, our results suggest that TaHY5-7A and TaBBX-3B collaboratively activate TaPpm1 expression to promote light-induced anthocyanin biosynthesis in purple-pericarp wheat.

17.
Postgrad Med ; 135(2): 121-127, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36222589

RESUMO

BACKGROUND: Papillary thyroid carcinoma (PTC) commonly presents with lymph node metastasis, which may be associated with worsened prognosis. This study aimed to comprehensively evaluate the risk factors of lymph node metastasis in PTC based on preoperative clinical and imaging data and to construct a nomogram model to predict the risk of lymph node metastasis. METHODS: A total of 989 patients with PTC were enrolled and randomly divided into training and validation cohorts in an 8:2 ratio. Independent risk factors for lymph node metastasis in PTC were analyzed using univariate and stepwise multivariate logistic regression. An importance analysis of independent risk factors affecting lymph node metastasis was performed according to the random forest method. Subsequently, a nomogram to predict lymph node metastasis was constructed, and the predictive effect of the nomogram was evaluated using receiver operating characteristic analysis and calibration curves. RESULTS: Univariate regression analysis revealed that age, sex, body weight, systolic blood pressure, free triiodothyronine, nodule location, nodule number, Thyroid Imaging Reporting and Data System (TI-RADS) grade on color Doppler ultrasound, enlarged lymph node present on imaging, and nodule diameter could affect lymph node metastasis in PTC. Stepwise multivariate regression analysis showed that sex, age, enlarged lymph node present on imaging, nodule diameter, and color Doppler TI-RADS grade were independent risk factors for lymph node metastasis in PTC. Combining these five independent risk factors, a nomogram prediction model was constructed. The area under the curve (AUC) of the nomogram in the training and validation cohorts was 0.742 and 0.765, respectively, with a well-fitted calibration curve. CONCLUSION: Our study showed that independent risk factors for lymph node metastasis in PTC were sex, age, enlarged lymph node present on imaging, nodule diameter, and color Doppler TI-RADS grade. The nomogram constructed based on these independent risk factors can better predict the risk of lymph node metastasis.


Assuntos
Neoplasias da Glândula Tireoide , Humanos , Linfonodos/patologia , Metástase Linfática/patologia , Estudos Retrospectivos , Fatores de Risco , Câncer Papilífero da Tireoide/patologia , Câncer Papilífero da Tireoide/cirurgia , Neoplasias da Glândula Tireoide/patologia
18.
Front Pharmacol ; 14: 1141420, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37168998

RESUMO

p53 mutations are prevalent in human cancers; approximately half of patients with esophageal cancer present these mutations. Mutant p53 (mutp53) exerts oncogenic functions that promote malignant tumor progression, invasion, metastasis, and drug resistance, resulting in poor prognosis. Some small molecules have been shown to mitigate the oncogenic function of mutp53 by restoring its wild-type activity. Although these molecules have been evaluated in clinical trials, none have been successfully used in the clinic. Here, we investigated the antitumor effects of phenethyl isothiocyanate (PEITC) in p53-mutant esophageal squamous cell carcinoma (ESCC) and elucidated its mechanism to identify new therapeutic strategies. We observed that p53R248Q is a DNA contact mutation and a structural mutation and that PEITC can restore the activity of p53R248Q in vitro and in vivo, further clarifying the antitumor activity of PEITC in cancers with different types of p53 mutations. PEITC can inhibit ESCC growth, induce apoptosis, and arrest cell cycle progression and has a preferential selectivity for ESCC with p53 mutations. Mechanistic studies showed that PEITC induced apoptosis and arrested cells at G2/M transition in cells expressing the p53R248Q mutant by restoring the wild-type conformation and transactivation function of p53; these effects were concentration dependent. Furthermore, PEITC inhibited the growth of subcutaneous xenografts in vivo and restored p53 mutant activity in xenografts. According to these findings, PEITC has antitumor effects, with its ability to restore p53R248Q activity being a key molecular event responsible for these effects.

19.
Oxid Med Cell Longev ; 2022: 9613095, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35615577

RESUMO

Hepatocellular carcinoma is a malignant tumor that poses a serious threat to human health. Ferroptosis, which represents an identified type of regulated iron-dependent cell death, may play an important role in hepatocellular carcinoma. However, it is unclear as to whether ferroptosis is involved with the mechanisms of lncRNA HULC in liver cancer cells. Here, we show that knockdown of HULC increases ferroptosis and oxidative stress in liver cancer cells. We also found changes in some related miRNAs in cells treated with HULC siRNA. Differential miRNA expression levels were determined with the use of high-throughput sequencing and prediction target genes identified using bioinformatics analysis. HULC was found to function as a ceRNA of miR-3200-5p, and miR-3200-5p regulates ferroptosis by targeting ATF4, resulting in the inhibition of proliferation and metastasis within HCC cells. In summary, these findings illuminate some of the molecular mechanisms through which downregulation of HULC induces liver cancer cell ferroptosis by targeting the miR-3200-5p/ATF4 axis to modulate the development of hepatocellular carcinoma.


Assuntos
Carcinoma Hepatocelular , Ferroptose , Neoplasias Hepáticas , MicroRNAs , RNA Longo não Codificante , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação para Baixo/genética , Ferroptose/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/patologia , MicroRNAs/genética , MicroRNAs/metabolismo
20.
J Immunother ; 45(5): 243-253, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35467579

RESUMO

Immunotherapy combined with chemotherapy has recently changed the first-line treatment of several cancers. We performed a systematic review and meta-analysis to assess the efficacy and safety of programmed cell death 1 (PD-1) inhibitor plus chemotherapy as a first-line treatment for advanced esophageal cancer. Data were collected from eligible studies searched from PubMed, Web of Science, Cochrane Library, Embase, and meeting abstracts. The pooled hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS) and the pooled odds ratios (ORs) for objective response rate and treatment-related adverse events (TRAEs) were estimated to assess the efficacy and safety of PD-1 inhibitor plus chemotherapy versus chemotherapy. We performed several subgroup analyses to explore the variables affecting immunotherapy efficacy in esophageal cancer. The 5-point Jadad scoring system, the bias risk assessment and sensitivity analyses were used to evaluate the quality of the meta-analysis. Compared with the chemotherapy group, the OS (HR=0.70; P<0.01) and PFS (HR=0.62; P<0.01) were significantly longer and the objective response rate (OR=2.07; P<0.01) was significantly higher in the PD-1 inhibitor plus chemotherapy group. An OS benefit was observed in patients regardless of histology or programmed cell death 1 ligand 1 combined positive score. OS and PFS were generally consistent across subgroups by clinical features. In safety analyses, PD-1 inhibitor plus chemotherapy had a significantly higher incidence of TRAEs (OR=1.85; P<0.01), but there was no significant difference in grade 3 or higher TRAEs (OR=1.24; P=0.05). Compared with chemotherapy, PD-1 inhibitor plus chemotherapy improves antitumor activity and controllable adverse events in the first-line treatment of advanced esophageal cancer.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Esofágicas , Neoplasias Pulmonares , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Esofágicas/tratamento farmacológico , Humanos , Inibidores de Checkpoint Imunológico , Neoplasias Pulmonares/tratamento farmacológico , Intervalo Livre de Progressão
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