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1.
Nat Immunol ; 24(10): 1671-1684, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37709985

RESUMO

Iron metabolism is pivotal for cell fitness in the mammalian host; however, its role in group 3 innate lymphoid cells (ILC3s) is unknown. Here we show that transferrin receptor CD71 (encoded by Tfrc)-mediated iron metabolism cell-intrinsically controls ILC3 proliferation and host protection against Citrobacter rodentium infection and metabolically affects mitochondrial respiration by switching of oxidative phosphorylation toward glycolysis. Iron deprivation or Tfrc ablation in ILC3s reduces the expression and/or activity of the aryl hydrocarbon receptor (Ahr), a key ILC3 regulator. Genetic ablation or activation of Ahr in ILC3s leads to CD71 upregulation or downregulation, respectively, suggesting Ahr-mediated suppression of CD71. Mechanistically, Ahr directly binds to the Tfrc promoter to inhibit transcription. Iron overload partially restores the defective ILC3 compartment in the small intestine of Ahr-deficient mice, consistent with the compensatory upregulation of CD71. These data collectively demonstrate an under-appreciated role of the Ahr-CD71-iron axis in the regulation of ILC3 maintenance and function.


Assuntos
Infecções por Enterobacteriaceae , Imunidade Inata , Animais , Camundongos , Linfócitos , Estado Nutricional , Ferro , Receptores da Transferrina/genética , Mamíferos
2.
Cell ; 177(3): 597-607.e9, 2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-31002796

RESUMO

The melanocortin 4 receptor (MC4R) is a G protein-coupled receptor whose disruption causes obesity. We functionally characterized 61 MC4R variants identified in 0.5 million people from UK Biobank and examined their associations with body mass index (BMI) and obesity-related cardiometabolic diseases. We found that the maximal efficacy of ß-arrestin recruitment to MC4R, rather than canonical Gαs-mediated cyclic adenosine-monophosphate production, explained 88% of the variance in the association of MC4R variants with BMI. While most MC4R variants caused loss of function, a subset caused gain of function; these variants were associated with significantly lower BMI and lower odds of obesity, type 2 diabetes, and coronary artery disease. Protective associations were driven by MC4R variants exhibiting signaling bias toward ß-arrestin recruitment and increased mitogen-activated protein kinase pathway activation. Harnessing ß-arrestin-biased MC4R signaling may represent an effective strategy for weight loss and the treatment of obesity-related cardiometabolic diseases.


Assuntos
Mutação com Ganho de Função/genética , Obesidade/patologia , Receptor Tipo 4 de Melanocortina/genética , Transdução de Sinais , Adulto , Idoso , Índice de Massa Corporal , Doença da Artéria Coronariana/complicações , Doença da Artéria Coronariana/metabolismo , Doença da Artéria Coronariana/patologia , AMP Cíclico/metabolismo , Bases de Dados Factuais , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Feminino , Subunidades alfa Gs de Proteínas de Ligação ao GTP/metabolismo , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/metabolismo , Polimorfismo de Nucleotídeo Único , Receptor Tipo 4 de Melanocortina/química , Receptor Tipo 4 de Melanocortina/metabolismo , beta-Arrestinas/metabolismo
3.
Cell ; 172(4): 758-770.e14, 2018 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-29425492

RESUMO

The means by which the physicochemical properties of different cellular components together determine bacterial cell shape remain poorly understood. Here, we investigate a programmed cell-shape change during Bacillus subtilis sporulation, when a rod-shaped vegetative cell is transformed to an ovoid spore. Asymmetric cell division generates a bigger mother cell and a smaller, hemispherical forespore. The septum traps the forespore chromosome, which is translocated to the forespore by SpoIIIE. Simultaneously, forespore size increases as it is reshaped into an ovoid. Using genetics, timelapse microscopy, cryo-electron tomography, and mathematical modeling, we demonstrate that forespore growth relies on membrane synthesis and SpoIIIE-mediated chromosome translocation, but not on peptidoglycan or protein synthesis. Our data suggest that the hydrated nucleoid swells and inflates the forespore, displacing ribosomes to the cell periphery, stretching septal peptidoglycan, and reshaping the forespore. Our results illustrate how simple biophysical interactions between core cellular components contribute to cellular morphology.


Assuntos
Divisão Celular Assimétrica/fisiologia , Bacillus subtilis/fisiologia , Cromossomos Bacterianos/metabolismo , Esporos Bacterianos/metabolismo , Translocação Genética , Bacillus subtilis/ultraestrutura , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Cromossomos Bacterianos/genética , Peptidoglicano/biossíntese , Peptidoglicano/genética , Biossíntese de Proteínas/fisiologia , Esporos Bacterianos/genética , Esporos Bacterianos/ultraestrutura
4.
Nature ; 598(7880): 368-372, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34526721

RESUMO

Transcription-coupled DNA repair removes bulky DNA lesions from the genome1,2 and protects cells against ultraviolet (UV) irradiation3. Transcription-coupled DNA repair begins when RNA polymerase II (Pol II) stalls at a DNA lesion and recruits the Cockayne syndrome protein CSB, the E3 ubiquitin ligase, CRL4CSA and UV-stimulated scaffold protein A (UVSSA)3. Here we provide five high-resolution structures of Pol II transcription complexes containing human transcription-coupled DNA repair factors and the elongation factors PAF1 complex (PAF) and SPT6. Together with biochemical and published3,4 data, the structures provide a model for transcription-repair coupling. Stalling of Pol II at a DNA lesion triggers replacement of the elongation factor DSIF by CSB, which binds to PAF and moves upstream DNA to SPT6. The resulting elongation complex, ECTCR, uses the CSA-stimulated translocase activity of CSB to pull on upstream DNA and push Pol II forward. If the lesion cannot be bypassed, CRL4CSA spans over the Pol II clamp and ubiquitylates the RPB1 residue K1268, enabling recruitment of TFIIH to UVSSA and DNA repair. Conformational changes in CRL4CSA lead to ubiquitylation of CSB and to release of transcription-coupled DNA repair factors before transcription may continue over repaired DNA.


Assuntos
Microscopia Crioeletrônica , Reparo do DNA , Complexos Multiproteicos/química , Complexos Multiproteicos/ultraestrutura , RNA Polimerase II/química , RNA Polimerase II/ultraestrutura , Transcrição Gênica , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Proteínas de Transporte/ultraestrutura , DNA Helicases/química , DNA Helicases/metabolismo , DNA Helicases/ultraestrutura , Enzimas Reparadoras do DNA/química , Enzimas Reparadoras do DNA/metabolismo , Enzimas Reparadoras do DNA/ultraestrutura , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/ultraestrutura , Humanos , Modelos Moleculares , Complexos Multiproteicos/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/química , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/ultraestrutura , RNA Polimerase II/metabolismo , Elongação da Transcrição Genética , Fator de Transcrição TFIIH/química , Fator de Transcrição TFIIH/metabolismo , Fator de Transcrição TFIIH/ultraestrutura , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Fatores de Transcrição/ultraestrutura , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/ultraestrutura , Ubiquitinação
5.
Nature ; 600(7890): 647-652, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34937899

RESUMO

Spin-ordered electronic states in hydrogen-terminated zigzag nanographene give rise to magnetic quantum phenomena1,2 that have sparked renewed interest in carbon-based spintronics3,4. Zigzag graphene nanoribbons (ZGNRs)-quasi one-dimensional semiconducting strips of graphene bounded by parallel zigzag edges-host intrinsic electronic edge states that are ferromagnetically ordered along the edges of the ribbon and antiferromagnetically coupled across its width1,2,5. Despite recent advances in the bottom-up synthesis of GNRs featuring symmetry protected topological phases6-8 and even metallic zero mode bands9, the unique magnetic edge structure of ZGNRs has long been obscured from direct observation by a strong hybridization of the zigzag edge states with the surface states of the underlying support10-15. Here, we present a general technique to thermodynamically stabilize and electronically decouple the highly reactive spin-polarized edge states by introducing a superlattice of substitutional N-atom dopants along the edges of a ZGNR. First-principles GW calculations and scanning tunnelling spectroscopy reveal a giant spin splitting of low-lying nitrogen lone-pair flat bands by an exchange field (~850 tesla) induced by the ferromagnetically ordered edge states of ZGNRs. Our findings directly corroborate the nature of the predicted emergent magnetic order in ZGNRs and provide a robust platform for their exploration and functional integration into nanoscale sensing and logic devices15-21.

6.
Nature ; 596(7872): 393-397, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34349265

RESUMO

Reproductive longevity is essential for fertility and influences healthy ageing in women1,2, but insights into its underlying biological mechanisms and treatments to preserve it are limited. Here we identify 290 genetic determinants of ovarian ageing, assessed using normal variation in age at natural menopause (ANM) in about 200,000 women of European ancestry. These common alleles were associated with clinical extremes of ANM; women in the top 1% of genetic susceptibility have an equivalent risk of premature ovarian insufficiency to those carrying monogenic FMR1 premutations3. The identified loci implicate a broad range of DNA damage response (DDR) processes and include loss-of-function variants in key DDR-associated genes. Integration with experimental models demonstrates that these DDR processes act across the life-course to shape the ovarian reserve and its rate of depletion. Furthermore, we demonstrate that experimental manipulation of DDR pathways highlighted by human genetics increases fertility and extends reproductive life in mice. Causal inference analyses using the identified genetic variants indicate that extending reproductive life in women improves bone health and reduces risk of type 2 diabetes, but increases the risk of hormone-sensitive cancers. These findings provide insight into the mechanisms that govern ovarian ageing, when they act, and how they might be targeted by therapeutic approaches to extend fertility and prevent disease.


Assuntos
Envelhecimento/genética , Ovário/metabolismo , Adulto , Alelos , Animais , Osso e Ossos/metabolismo , Quinase 1 do Ponto de Checagem/genética , Quinase do Ponto de Checagem 2/genética , Diabetes Mellitus Tipo 2 , Dieta , Europa (Continente)/etnologia , Ásia Oriental/etnologia , Feminino , Fertilidade/genética , Proteína do X Frágil da Deficiência Intelectual/genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Envelhecimento Saudável/genética , Humanos , Longevidade/genética , Menopausa/genética , Menopausa Precoce/genética , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Insuficiência Ovariana Primária/genética , Útero
7.
Nature ; 579(7799): 448-451, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32188943

RESUMO

Chromatin-remodelling complexes of the SWI/SNF family function in the formation of nucleosome-depleted, transcriptionally active promoter regions (NDRs)1,2. In the yeast Saccharomyces cerevisiae, the essential SWI/SNF complex RSC3 contains 16 subunits, including the ATP-dependent DNA translocase Sth14,5. RSC removes nucleosomes from promoter regions6,7 and positions the specialized +1 and -1 nucleosomes that flank NDRs8,9. Here we present the cryo-electron microscopy structure of RSC in complex with a nucleosome substrate. The structure reveals that RSC forms five protein modules and suggests key features of the remodelling mechanism. The body module serves as a scaffold for the four flexible modules that we call DNA-interacting, ATPase, arm and actin-related protein (ARP) modules. The DNA-interacting module binds extra-nucleosomal DNA and is involved in the recognition of promoter DNA elements8,10,11 that influence RSC functionality12. The ATPase and arm modules sandwich the nucleosome disc with the Snf2 ATP-coupling (SnAC) domain and the finger helix, respectively. The translocase motor of the ATPase module engages with the edge of the nucleosome at superhelical location +2. The mobile ARP module may modulate translocase-nucleosome interactions to regulate RSC activity5. The RSC-nucleosome structure provides a basis for understanding NDR formation and the structure and function of human SWI/SNF complexes that are frequently mutated in cancer13.


Assuntos
Microscopia Crioeletrônica , Complexos Multiproteicos/química , Complexos Multiproteicos/ultraestrutura , Nucleossomos/metabolismo , Nucleossomos/ultraestrutura , Saccharomyces cerevisiae/química , Adenosina Trifosfatases/química , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/ultraestrutura , Sequência de Aminoácidos , Animais , Transporte Biológico , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/ultraestrutura , Drosophila melanogaster , Humanos , Camundongos , Modelos Moleculares , Complexos Multiproteicos/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Proteínas Nucleares/ultraestrutura , Nucleossomos/química , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Saccharomyces cerevisiae/ultraestrutura , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/ultraestrutura , Xenopus laevis
8.
Mol Syst Biol ; 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38907068

RESUMO

Mass spectrometry has revolutionized cell signaling research by vastly simplifying the analysis of many thousands of phosphorylation sites in the human proteome. Defining the cellular response to perturbations is crucial for further illuminating the functionality of the phosphoproteome. Here we describe µPhos ('microPhos'), an accessible phosphoproteomics platform that permits phosphopeptide enrichment from 96-well cell culture and small tissue amounts in <8 h total processing time. By greatly minimizing transfer steps and liquid volumes, we demonstrate increased sensitivity, >90% selectivity, and excellent quantitative reproducibility. Employing highly sensitive trapped ion mobility mass spectrometry, we quantify ~17,000 Class I phosphosites in a human cancer cell line using 20 µg starting material, and confidently localize ~6200 phosphosites from 1 µg. This depth covers key signaling pathways, rendering sample-limited applications and perturbation experiments with hundreds of samples viable. We employ µPhos to study drug- and time-dependent response signatures in a leukemia cell line, and by quantifying 30,000 Class I phosphosites in the mouse brain we reveal distinct spatial kinase activities in subregions of the hippocampal formation.

9.
Nature ; 575(7784): 652-657, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31748747

RESUMO

Mosaic loss of chromosome Y (LOY) in circulating white blood cells is the most common form of clonal mosaicism1-5, yet our knowledge of the causes and consequences of this is limited. Here, using a computational approach, we estimate that 20% of the male population represented in the UK Biobank study (n = 205,011) has detectable LOY. We identify 156 autosomal genetic determinants of LOY, which we replicate in 757,114 men of European and Japanese ancestry. These loci highlight genes that are involved in cell-cycle regulation and cancer susceptibility, as well as somatic drivers of tumour growth and targets of cancer therapy. We demonstrate that genetic susceptibility to LOY is associated with non-haematological effects on health in both men and women, which supports the hypothesis that clonal haematopoiesis is a biomarker of genomic instability in other tissues. Single-cell RNA sequencing identifies dysregulated expression of autosomal genes in leukocytes with LOY and provides insights into why clonal expansion of these cells may occur. Collectively, these data highlight the value of studying clonal mosaicism to uncover fundamental mechanisms that underlie cancer and other ageing-related diseases.


Assuntos
Deleção Cromossômica , Cromossomos Humanos Y/genética , Predisposição Genética para Doença/genética , Instabilidade Genômica/genética , Leucócitos/patologia , Mosaicismo , Adulto , Idoso , Biologia Computacional , Bases de Dados Genéticas , Feminino , Marcadores Genéticos/genética , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/genética , Reino Unido
10.
PLoS Genet ; 18(6): e1010162, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35653391

RESUMO

Diet is considered as one of the most important modifiable factors influencing human health, but efforts to identify foods or dietary patterns associated with health outcomes often suffer from biases, confounding, and reverse causation. Applying Mendelian randomization in this context may provide evidence to strengthen causality in nutrition research. To this end, we first identified 283 genetic markers associated with dietary intake in 445,779 UK Biobank participants. We then converted these associations into direct genetic effects on food exposures by adjusting them for effects mediated via other traits. The SNPs which did not show evidence of mediation were then used for MR, assessing the association between genetically predicted food choices and other risk factors, health outcomes. We show that using all associated SNPs without omitting those which show evidence of mediation, leads to biases in downstream analyses (genetic correlations, causal inference), similar to those present in observational studies. However, MR analyses using SNPs which have only a direct effect on the exposure on food exposures provided unequivocal evidence of causal associations between specific eating patterns and obesity, blood lipid status, and several other risk factors and health outcomes.


Assuntos
Ingestão de Alimentos , Variação Genética , Causalidade , Humanos , Avaliação de Resultados em Cuidados de Saúde , Fatores de Risco
11.
Nano Lett ; 24(17): 5387-5392, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38629638

RESUMO

Topological phases in laterally confined low-dimensional nanographenes have emerged as versatile design tools that can imbue otherwise unremarkable materials with exotic band structures ranging from topological semiconductors and quantum dots to intrinsically metallic bands. The periodic boundary conditions that define the topology of a given lattice have thus far prevented the translation of this technology to the quasi-zero-dimensional (0D) domain of small molecular structures. Here, we describe the synthesis of a polycyclic aromatic hydrocarbon (PAH) featuring two localized zero modes (ZMs) formed by the topological junction interface between a trivial and nontrivial phase within a single molecule. First-principles density functional theory calculations predict a strong hybridization between adjacent ZMs that gives rise to an exceptionally small HOMO-LUMO gap. Scanning tunneling microscopy and spectroscopy corroborate the molecular structure of 9/7/9-double quantum dots and reveal an experimental quasiparticle gap of 0.16 eV, corresponding to a carbon-based small molecule long-wavelength infrared (LWIR) absorber.

12.
BMC Genomics ; 25(1): 208, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38408933

RESUMO

BACKGROUND: Polycystic ovary syndrome (PCOS) is a complex multifactorial disorder with a substantial genetic component. However, the clinical manifestations of PCOS are heterogeneous with notable differences between lean and obese women, implying a different pathophysiology manifesting in differential body mass index (BMI). We performed a meta-analysis of genome-wide association study (GWAS) data from six well-characterised cohorts, using a case-control study design stratified by BMI, aiming to identify genetic variants associated with lean and overweight/obese PCOS subtypes. RESULTS: The study comprised 254,588 women (5,937 cases and 248,651 controls) from individual studies performed in Australia, Estonia, Finland, the Netherlands and United States of America, and separated according to three BMI stratifications (lean, overweight and obese). Genome-wide association analyses were performed for each stratification within each cohort, with the data for each BMI group meta-analysed using METAL software. Almost half of the total study population (47%, n = 119,584) were of lean BMI (≤ 25 kg/m2). Two genome-wide significant loci were identified for lean PCOS, led by rs12000707 within DENND1A (P = 1.55 × 10-12) and rs2228260 within XBP1 (P = 3.68 × 10-8). One additional locus, LINC02905, was highlighted as significantly associated with lean PCOS through gene-based analyses (P = 1.76 × 10-6). There were no significant loci observed for the overweight or obese sub-strata when analysed separately, however, when these strata were combined, an association signal led by rs569675099 within DENND1A reached genome-wide significance (P = 3.22 × 10-9) and a gene-based association was identified with ERBB4 (P = 1.59 × 10-6). Nineteen of 28 signals identified in previous GWAS, were replicated with consistent allelic effect in the lean stratum. There were less replicated signals in the overweight and obese groups, and only 4 SNPs were replicated in each of the three BMI strata. CONCLUSIONS: Genetic variation at the XBP1, LINC02905 and ERBB4 loci were associated with PCOS within unique BMI strata, while DENND1A demonstrated associations across multiple strata, providing evidence of both distinct and shared genetic features between lean and overweight/obese PCOS-affected women. This study demonstrated that PCOS-affected women with contrasting body weight are not only phenotypically distinct but also show variation in genetic architecture; lean PCOS women typically display elevated gonadotrophin ratios, lower insulin resistance, higher androgen levels, including adrenal androgens, and more favourable lipid profiles. Overall, these findings add to the growing body of evidence supporting a genetic basis for PCOS as well as differences in genetic patterns relevant to PCOS BMI-subtype.


Assuntos
Estudo de Associação Genômica Ampla , Síndrome do Ovário Policístico , Feminino , Humanos , Índice de Massa Corporal , Sobrepeso/genética , Estudos de Casos e Controles , Síndrome do Ovário Policístico/genética , Síndrome do Ovário Policístico/complicações , Obesidade/genética
13.
J Am Chem Soc ; 146(23): 15879-15886, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38813680

RESUMO

The integration of low-energy states into bottom-up engineered graphene nanoribbons (GNRs) is a robust strategy for realizing materials with tailored electronic band structure for nanoelectronics. Low-energy zero-modes (ZMs) can be introduced into nanographenes (NGs) by creating an imbalance between the two sublattices of graphene. This phenomenon is exemplified by the family of [n]triangulenes (n ∈ N). Here, we demonstrate the synthesis of [3]triangulene-GNRs, a regioregular one-dimensional (1D) chain of [3]triangulenes linked by five-membered rings. Hybridization between ZMs on adjacent [3]triangulenes leads to the emergence of a narrow band gap, Eg,exp ∼ 0.7 eV, and topological end states that are experimentally verified using scanning tunneling spectroscopy. Tight-binding and first-principles density functional theory calculations within the local density approximation corroborate our experimental observations. Our synthetic design takes advantage of a selective on-surface head-to-tail coupling of monomer building blocks enabling the regioselective synthesis of [3]triangulene-GNRs. Detailed ab initio theory provides insights into the mechanism of on-surface radical polymerization, revealing the pivotal role of Au-C bond formation/breakage in driving selectivity.

14.
Br J Cancer ; 130(1): 114-124, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38057395

RESUMO

BACKGROUND: The association of fitness with cancer risk is not clear. METHODS: We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for risk of lung, colorectal, endometrial, breast, and prostate cancer in a subset of UK Biobank participants who completed a submaximal fitness test in 2009-12 (N = 72,572). We also investigated relationships using two-sample Mendelian randomisation (MR), odds ratios (ORs) were estimated using the inverse-variance weighted method. RESULTS: After a median of 11 years of follow-up, 4290 cancers of interest were diagnosed. A 3.5 ml O2⋅min-1⋅kg-1 total-body mass increase in fitness (equivalent to 1 metabolic equivalent of task (MET), approximately 0.5 standard deviation (SD)) was associated with lower risks of endometrial (HR = 0.81, 95% CI: 0.73-0.89), colorectal (0.94, 0.90-0.99), and breast cancer (0.96, 0.92-0.99). In MR analyses, a 0.5 SD increase in genetically predicted O2⋅min-1⋅kg-1 fat-free mass was associated with a lower risk of breast cancer (OR = 0.92, 95% CI: 0.86-0.98). After adjusting for adiposity, both the observational and genetic associations were attenuated. DISCUSSION: Higher fitness levels may reduce risks of endometrial, colorectal, and breast cancer, though relationships with adiposity are complex and may mediate these relationships. Increasing fitness, including via changes in body composition, may be an effective strategy for cancer prevention.


Assuntos
Neoplasias da Mama , Aptidão Cardiorrespiratória , Neoplasias Colorretais , Masculino , Humanos , Bancos de Espécimes Biológicos , Biobanco do Reino Unido , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/diagnóstico , Fatores de Risco
15.
J Comput Chem ; 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38795379

RESUMO

The previously introduced workflow to achieve an energetically and structurally optimized description of frontier bonds in quantum mechanical/molecular mechanics (QM/MM)-type applications was extended into the regime of computational material sciences at the example of a layered carbon model systems. Optimized QM/MM link bond parameters at HSEsol/6-311G(d,p) and self-consistent density functional tight binding (SCC-DFTB) were derived for graphitic systems, enabling detailed investigation of specific structure motifs occurring in graphene-derived structures v i a $$ via $$ quantum-chemical calculations. Exemplary molecular dynamics (MD) simulations in the isochoric-isothermic (NVT) ensemble were carried out to study the intercalation of lithium and the properties of the Stone-Thrower-Wales defect. The diffusivity of lithium as well as hydrogen and proton adsorption on a defective graphene surface served as additional example. The results of the QM/MM MD simulations provide detailed insight into the applicability of the employed link-bond strategy when studying intercalation and adsorption properties of graphitic materials.

16.
Phys Chem Chem Phys ; 26(3): 1729-1740, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38165417

RESUMO

In this work a previously established QM/MM simulation protocol for the treatment of solid-state interfaces was extended towards the treatment of layered bulk materials enabling for instance investigation of metal intercalation in graphitic carbon materials. In order to study the intercalation of Li in graphite, new density functional tight binding (DFTB) parameters for Li have been created. Molecular dynamics (MD) simulations at constant temperatures (273.15, 298.15 and 323.15 K) have been carried out to assess the performance of the presented DFTB MD simulation approach. The intercalation of variable lithium and sodium content was investigated via z-distribution functions and analysis of the diffusivity in the direction parallel to the graphene plane. Both the calculated diffusion coefficients and the activation energy in case of lithium are in good agreement with experimental data. The comparison of the QM/MM MD simulation results provide detailed insights into the structural and dynamical properties of intercalated metal ions.

17.
Phys Chem Chem Phys ; 26(18): 13814-13825, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38655773

RESUMO

The development and characterization of materials for solid oxide fuel cells (SOFC) is an important step towards sustainable energy technologies. This present study models cubic CeO2, Gd2O3, and gadolinium-doped ceria (GDC) using newly constructed interaction potentials based on a partial atom charge framework. The interaction model was validated by comparing the structural properties with experimental reference data, which were found to be in good agreement. Validation of the potential model was conducted considering the surface stability of CeO2 and Gd2O3. Additionally, the accuracy of the novel potential model was assessed by comparing the oxygen diffusion coefficient in GDCn (n = 4-15) and the associated activation energy. The results demonstrate that the novel potential model is capable of describing the oxygen diffusion in GDC. In addition, this study compares the vibrational properties of the bulk with density functional theory (DFT) calculations, using a harmonic frequency analysis that avoids the need for computationally expensive quantum mechanical molecular dynamics (QM MD) simulations. The potential is compatible with a reactive water model, thus providing a framework for the simulation of solid-liquid interfaces.

18.
Nature ; 560(7717): 204-208, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30089918

RESUMO

Topological insulators are an emerging class of materials that host highly robust in-gap surface or interface states while maintaining an insulating bulk1,2. Most advances in this field have focused on topological insulators and related topological crystalline insulators3 in two dimensions4-6 and three dimensions7-10, but more recent theoretical work has predicted the existence of one-dimensional symmetry-protected topological phases in graphene nanoribbons (GNRs)11. The topological phase of these laterally confined, semiconducting strips of graphene is determined by their width, edge shape and terminating crystallographic unit cell and is characterized by a [Formula: see text] invariant12 (that is, an index of either 0 or 1, indicating two topological classes-similar to quasi-one-dimensional solitonic systems13-16). Interfaces between topologically distinct GNRs characterized by different values of [Formula: see text] are predicted to support half-filled, in-gap localized electronic states that could, in principle, be used as a tool for material engineering11. Here we present the rational design and experimental realization of a topologically engineered GNR superlattice that hosts a one-dimensional array of such states, thus generating otherwise inaccessible electronic structures. This strategy also enables new end states to be engineered directly into the termini of the one-dimensional GNR superlattice. Atomically precise topological GNR superlattices were synthesized from molecular precursors on a gold surface, Au(111), under ultrahigh-vacuum conditions and characterized by low-temperature scanning tunnelling microscopy and spectroscopy. Our experimental results and first-principles calculations reveal that the frontier band structure (the bands bracketing filled and empty states) of these GNR superlattices is defined purely by the coupling between adjacent topological interface states. This manifestation of non-trivial one-dimensional topological phases presents a route to band engineering in one-dimensional materials based on precise control of their electronic topology, and is a promising platform for studies of one-dimensional quantum spin physics.

19.
J Am Soc Nephrol ; 34(3): 369-373, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36735391

RESUMO

SIGNIFICANCE STATEMENT: Membranous nephropathy (MN) is an autoimmune kidney disease characterized by immune deposits in the glomerular basement membrane. Circulating anti-phospholipase A 2 receptor 1 (PLA 2 R1) antibodies are detectable in 70%-80% of patients with MN, but experimental evidence of pathogenicity has been lacking. This study demonstrates the pathogenicity of human anti-PLA 2 R1 antibodies in minipigs, a model for MN that intrinsically expresses PLA 2 R1 on podocytes. After passive transfer of human anti-PLA 2 R1 antibody-containing plasma from patients with PLA 2 R1-associated MN to minipigs, antibodies were detected in the minipig glomeruli, but not in response to plasma from healthy controls. The minipigs developed histomorphological characteristics of MN, local complement activation in the glomeruli, and low-level proteinuria within 7 days, showing that human anti-PLA 2 R1 antibodies are pathogenic. BACKGROUND: Primary membranous nephropathy (MN) is an autoimmune kidney disease in which immune complexes are deposited beneath the epithelium in the glomeruli. The condition introduces a high risk for end-stage kidney disease. Seventy percent to 80% of patients with MN have circulating antibodies against phospholipase A 2 receptor 1 (PLA 2 R1), and levels correlate with treatment response and prognosis. However, experimental evidence that human anti-PLA 2 R1 antibodies induce MN has been elusive. METHODS: In passive transfer experiments, minipigs received plasma or purified IgG from patients with PLA 2 R1-associated MN or from healthy controls. Anti-PLA 2 R1 antibodies and proteinuria were monitored using Western blot, ELISA, and Coomassie staining. Kidney tissues were analyzed using immunohistochemistry, immunofluorescence, electron microscopy, and proteomic analyses. RESULTS: Minipigs, like humans, express PLA 2 R1 on podocytes. Human anti-PLA 2 R1 antibodies bound to minipig PLA 2 R1 in vitro and in vivo . Passive transfer of human anti-PLA 2 R1 antibodies from patients with PLA 2 R1-associated MN to minipigs led to histological characteristics of human early-stage MN, activation of components of the complement cascade, and low levels of proteinuria. We observed development of an autologous, later phase of disease. CONCLUSIONS: A translational approach from humans to minipigs showed that human anti-PLA 2 R1 antibodies are pathogenic in MN, although in the heterologous phase of disease only low-level proteinuria developed.


Assuntos
Doenças Autoimunes , Glomerulonefrite Membranosa , Humanos , Animais , Suínos , Porco Miniatura/metabolismo , Projetos Piloto , Virulência , Proteômica , Autoanticorpos , Proteinúria , Receptores da Fosfolipase A2
20.
J Am Chem Soc ; 145(35): 19338-19346, 2023 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-37611208

RESUMO

Substitutional heteroatom doping of bottom-up engineered 1D graphene nanoribbons (GNRs) is a versatile tool for realizing low-dimensional functional materials for nanoelectronics and sensing. Previous efforts have largely relied on replacing C-H groups lining the edges of GNRs with trigonal planar N atoms. This type of atomically precise doping, however, only results in a modest realignment of the valence band (VB) and conduction band (CB) energies. Here, we report the design, bottom-up synthesis, and spectroscopic characterization of nitrogen core-doped 5-atom-wide armchair GNRs (N2-5-AGNRs) that yield much greater energy-level shifting of the GNR electronic structure. Here, the substitution of C atoms with N atoms along the backbone of the GNR introduces a single surplus π-electron per dopant that populates the electronic states associated with previously unoccupied bands. First-principles DFT-LDA calculations confirm that a sizable shift in Fermi energy (∼1.0 eV) is accompanied by a broad reconfiguration of the band structure, including the opening of a new band gap and the transition from a direct to an indirect semiconducting band gap. Scanning tunneling spectroscopy (STS) lift-off charge transport experiments corroborate the theoretical results and reveal the relationship among substitutional heteroatom doping, Fermi-level shifting, electronic band structure, and topological engineering for this new N-doped GNR.

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