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1.
Nature ; 592(7852): 60-64, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33790443

RESUMO

Amorphous solids such as glass, plastics and amorphous thin films are ubiquitous in our daily life and have broad applications ranging from telecommunications to electronics and solar cells1-4. However, owing to the lack of long-range order, the three-dimensional (3D) atomic structure of amorphous solids has so far eluded direct experimental determination5-15. Here we develop an atomic electron tomography reconstruction method to experimentally determine the 3D atomic positions of an amorphous solid. Using a multi-component glass-forming alloy as proof of principle, we quantitatively characterize the short- and medium-range order of the 3D atomic arrangement. We observe that, although the 3D atomic packing of the short-range order is geometrically disordered, some short-range-order structures connect with each other to form crystal-like superclusters and give rise to medium-range order. We identify four types of crystal-like medium-range order-face-centred cubic, hexagonal close-packed, body-centred cubic and simple cubic-coexisting in the amorphous sample, showing translational but not orientational order. These observations provide direct experimental evidence to support the general framework of the efficient cluster packing model for metallic glasses10,12-14,16. We expect that this work will pave the way for the determination of the 3D structure of a wide range of amorphous solids, which could transform our fundamental understanding of non-crystalline materials and related phenomena.

2.
Nature ; 570(7762): 500-503, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31243385

RESUMO

Nucleation plays a critical role in many physical and biological phenomena that range from crystallization, melting and evaporation to the formation of clouds and the initiation of neurodegenerative diseases1-3. However, nucleation is a challenging process to study experimentally, especially in its early stages, when several atoms or molecules start to form a new phase from a parent phase. A number of experimental and computational methods have been used to investigate nucleation processes4-17, but experimental determination of the three-dimensional atomic structure and the dynamics of early-stage nuclei has been unachievable. Here we use atomic electron tomography to study early-stage nucleation in four dimensions (that is, including time) at atomic resolution. Using FePt nanoparticles as a model system, we find that early-stage nuclei are irregularly shaped, each has a core of one to a few atoms with the maximum order parameter, and the order parameter gradient points from the core to the boundary of the nucleus. We capture the structure and dynamics of the same nuclei undergoing growth, fluctuation, dissolution, merging and/or division, which are regulated by the order parameter distribution and its gradient. These experimental observations are corroborated by molecular dynamics simulations of heterogeneous and homogeneous nucleation in liquid-solid phase transitions of Pt. Our experimental and molecular dynamics results indicate that a theory beyond classical nucleation theory1,2,18 is needed to describe early-stage nucleation at the atomic scale. We anticipate that the reported approach will open the door to the study of many fundamental problems in materials science, nanoscience, condensed matter physics and chemistry, such as phase transition, atomic diffusion, grain boundary dynamics, interface motion, defect dynamics and surface reconstruction with four-dimensional atomic resolution.

3.
Am J Respir Crit Care Med ; 210(1): 108-118, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38668710

RESUMO

Rationale: Nontuberculous mycobacteria (NTM) are prevalent among patients with bronchiectasis. However, the long-term natural history of patients with NTM and bronchiectasis is not well described. Objectives: To assess the impact of NTM on 5-year clinical outcomes and mortality in patients with bronchiectasis. Methods: Patients in the Bronchiectasis and NTM Research Registry with ⩾5 years of follow-up were eligible. Data were collected for all-cause mortality, lung function, exacerbations, hospitalizations, and disease severity. Outcomes were compared between patients with and without NTM at baseline. Mortality was assessed using Cox proportional hazards models and the log-rank test. Measurements and Main Results: In total, 2,634 patients were included: 1,549 (58.8%) with and 1,085 (41.2%) without NTM at baseline. All-cause mortality (95% confidence interval) at Year 5 was 12.1% (10.5%, 13.7%) overall, 12.6% (10.5%, 14.8%) in patients with NTM, and 11.5% (9.0%, 13.9%) in patients without NTM. Independent predictors of 5-year mortality were baseline FEV1 percent predicted, age, hospitalization within 2 years before baseline, body mass index, and sex (all P < 0.01). The probabilities of acquiring NTM or Pseudomonas aeruginosa were approximately 4% and 3% per year, respectively. Spirometry, exacerbations, and hospitalizations were similar, regardless of NTM status, except that annual exacerbations were lower in patients with NTM (P < 0.05). Conclusions: Outcomes, including exacerbations, hospitalizations, rate of loss of lung function, and mortality rate, were similar across 5 years in patients with bronchiectasis with or without NTM.


Assuntos
Bronquiectasia , Infecções por Mycobacterium não Tuberculosas , Sistema de Registros , Humanos , Bronquiectasia/mortalidade , Bronquiectasia/fisiopatologia , Bronquiectasia/epidemiologia , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Infecções por Mycobacterium não Tuberculosas/mortalidade , Infecções por Mycobacterium não Tuberculosas/epidemiologia , Estados Unidos/epidemiologia , Hospitalização/estatística & dados numéricos , Modelos de Riscos Proporcionais , Micobactérias não Tuberculosas , Progressão da Doença
4.
J Neuroinflammation ; 21(1): 129, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38745337

RESUMO

Diet-induced increase in body weight is a growing health concern worldwide. Often accompanied by a low-grade metabolic inflammation that changes systemic functions, diet-induced alterations may contribute to neurodegenerative disorder progression as well. This study aims to non-invasively investigate diet-induced metabolic and inflammatory effects in the brain of an APPPS1 mouse model of Alzheimer's disease. [18F]FDG, [18F]FTHA, and [18F]GE-180 were used for in vivo PET imaging in wild-type and APPPS1 mice. Ex vivo flow cytometry and histology in brains complemented the in vivo findings. 1H- magnetic resonance spectroscopy in the liver, plasma metabolomics and flow cytometry of the white adipose tissue were used to confirm metaflammatory condition in the periphery. We found disrupted glucose and fatty acid metabolism after Western diet consumption, with only small regional changes in glial-dependent neuroinflammation in the brains of APPPS1 mice. Further ex vivo investigations revealed cytotoxic T cell involvement in the brains of Western diet-fed mice and a disrupted plasma metabolome. 1H-magentic resonance spectroscopy and immunological results revealed diet-dependent inflammatory-like misbalance in livers and fatty tissue. Our multimodal imaging study highlights the role of the brain-liver-fat axis and the adaptive immune system in the disruption of brain homeostasis in amyloid models of Alzheimer's disease.


Assuntos
Imunidade Adaptativa , Amiloidose , Encéfalo , Dieta Ocidental , Modelos Animais de Doenças , Camundongos Transgênicos , Animais , Camundongos , Encéfalo/metabolismo , Encéfalo/patologia , Encéfalo/diagnóstico por imagem , Encéfalo/imunologia , Amiloidose/metabolismo , Amiloidose/patologia , Amiloidose/imunologia , Dieta Ocidental/efeitos adversos , Camundongos Endogâmicos C57BL , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Doença de Alzheimer/imunologia
5.
Nano Lett ; 23(17): 8000-8005, 2023 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-37639696

RESUMO

We investigate the electronic properties of a graphene and α-ruthenium trichloride (α-RuCl3) heterostructure using a combination of experimental techniques. α-RuCl3 is a Mott insulator and a Kitaev material. Its combination with graphene has gained increasing attention due to its potential applicability in novel optoelectronic devices. By using a combination of spatially resolved photoemission spectroscopy and low-energy electron microscopy, we are able to provide a direct visualization of the massive charge transfer from graphene to α-RuCl3, which can modify the electronic properties of both materials, leading to novel electronic phenomena at their interface. A measurement of the spatially resolved work function allows for a direct estimate of the interface dipole between graphene and α-RuCl3. Their strong coupling could lead to new ways of manipulating electronic properties of a two-dimensional heterojunction. Understanding the electronic properties of this structure is pivotal for designing next generation low-power optoelectronics devices.

6.
Int J Mol Sci ; 25(5)2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38474156

RESUMO

Obesity represents a worldwide health challenge, and the condition is accompanied by elevated risk of cardiovascular diseases caused by metabolic dysfunction and proinflammatory adipokines. Among those, the immune-modulatory cathelicidin antimicrobial peptide (human: CAMP; murine: CRAMP) might contribute to the interaction of the innate immune system and metabolism in these settings. We investigated systemic CAMP/CRAMP levels in experimental murine models of atherosclerosis, myocardial infarction and cardiovascular patients. Atherosclerosis was induced in low-density lipoprotein receptor-deficient (Ldlr-/-) mice by high-fat diet (HFD). C57BL/6J wild-type mice were subjected to myocardial infarction by permanent or transient left anterior descending (LAD)-ligation. Cramp gene expression in murine organs and tissues was investigated via real-time PCR. Blood samples of 234 adult individuals with or without coronary artery disease (CAD) were collected. Human and murine CAMP/CRAMP serum levels were quantified by ELISA. Atherosclerotic mice exhibited significantly increased CRAMP serum levels and induced Cramp gene expression in the spleen and liver, whereas experimental myocardial infarction substantially decreased CRAMP serum levels. Human CAMP serum quantities were not significantly affected by CAD while being correlated with leukocytes and pro-inflammatory cytokines. Our data show an influence of cathelicidin in experimental atherosclerosis, myocardial infarction, as well as in patients with CAD. Further studies are needed to elucidate the pathophysiological mechanism.


Assuntos
Aterosclerose , Doença da Artéria Coronariana , Infarto do Miocárdio , Adulto , Animais , Humanos , Camundongos , Peptídeos Catiônicos Antimicrobianos/metabolismo , Catelicidinas , Camundongos Endogâmicos C57BL , Camundongos Knockout
7.
Nat Mater ; 21(1): 95-102, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34663951

RESUMO

Liquids and solids are two fundamental states of matter. However, our understanding of their three-dimensional atomic structure is mostly based on physical models. Here we use atomic electron tomography to experimentally determine the three-dimensional atomic positions of monatomic amorphous solids, namely a Ta thin film and two Pd nanoparticles. We observe that pentagonal bipyramids are the most abundant atomic motifs in these amorphous materials. Instead of forming icosahedra, the majority of pentagonal bipyramids arrange into pentagonal bipyramid networks with medium-range order. Molecular dynamics simulations further reveal that pentagonal bipyramid networks are prevalent in monatomic metallic liquids, which rapidly grow in size and form more icosahedra during the quench from the liquid to the glass state. These results expand our understanding of the atomic structures of amorphous solids and will encourage future studies on amorphous-crystalline phase and glass transitions in non-crystalline materials with three-dimensional atomic resolution.

8.
Nano Lett ; 22(16): 6678-6684, 2022 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-35939526

RESUMO

Chiral spin textures are fundamentally interesting, with promise for device applications. Stabilizing chirality is conventionally achieved by introducing Dzyaloshinskii-Moriya interaction (DMI) in asymmetric multilayers, where the thickness of each layer is at least a few monolayers. Here we report an ultrasensitive chirality switching in (Ni/Co)n multilayer induced by capping with only 0.22 monolayer of Pd. Using spin-polarized low-energy electron microscopy, we monitor the gradual evolution of domain walls from left-handed to right-handed Néel walls and quantify the DMI induced by the Pd capping layer. We also observe the chiral evolution of a skyrmion during the DMI switching, where no significant topological protection is found as the skyrmion winding number varies. This corresponds to a minimum energy cost of <1 attojoule during the skyrmion chirality switching. Our results demonstrate the detailed chirality evolution within skyrmions during the DMI sign switching, which is relevant to practical applications of skyrmionic devices.

9.
Int J Mol Sci ; 24(16)2023 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-37629082

RESUMO

Recent investigation has revealed the significant role of Cathelicidin antimicrobial peptide (CAMP) in infection defense and innate immunity processes in adipose tissue. Meanwhile, knowledge of its regulation and functions in metabolic contexts as an adipokine remains sparce. The present study investigated the postprandial regulation of circulating CAMP levels during oral glucose tolerance tests (OGTTs). Eighty-six metabolically healthy volunteers participated in a standardized 75 g-2 h-OGTT setting. The effects of exogenous glucose, insulin, and incretins on CAMP expression in human adipocyte culture (cell-line SGBS) were studied in vitro. CAMP concentrations in blood serum samples were measured by ELISA techniques and adipocyte gene expression levels were quantified by real-time PCR. Of note, base-line CAMP serum quantities were negatively correlated with HDL cholesterol levels as well as with the anti-inflammatory adipokine adiponectin. During the 2 h following glucose ingestion, a significant rise in circulating CAMP concentrations was observed in considerable contrast to reduced quantities of fatty acid binding proteins (FABP) 2 and 4 and dipeptidyl peptidase 4 (DPP4). In SGBS adipocytes, neither differing glucose levels nor insulin or incretin treatment significantly induced CAMP mRNA levels. According to our data, glucose represents a positive postprandial regulator of systemic CAMP. This effect apparently is not mediated by the regulatory impact of glucose metabolism on adipocyte CAMP expression.


Assuntos
Catelicidinas , Glucose , Humanos , Teste de Tolerância a Glucose , Catelicidinas/farmacologia , Incretinas , Insulina , Insulina Regular Humana , Adipocinas
10.
Int J Mol Sci ; 24(21)2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37958808

RESUMO

Understanding the complex interactions between metabolism and the immune system ("metaflammation") is crucial for the identification of key immunomodulatory factors as potential therapeutic targets in obesity and in cardiovascular diseases. Cathelicidin antimicrobial peptide (CAMP) is an important factor of innate immunity and is expressed in adipocytes. CAMP, therefore, might play a role as an adipokine in metaflammation and adipose inflammation. TNFα, cell-free nucleic acids (cfDNA), and toll-like receptor (TLR) 9 are components of the innate immune system and are functionally active in adipose tissue. The aim of the present study was to investigate the impact of TNFα and cfDNA on CAMP expression in adipocytes. Since cfDNA acts as a physiological TLR9 agonist, we additionally investigated TLR9-mediated CAMP regulation in adipocytes and adipose tissue. CAMP gene expression in murine 3T3-L1 and human SGBS adipocytes and in murine and human adipose tissues was quantified by real-time PCR. Adipocyte inflammation was induced in vitro by TNFα and cfDNA stimulation. Serum CAMP concentrations in TLR9 knockout (KO) and in wildtype mice were quantified by ELISA. In primary adipocytes of wildtype and TLR9 KO mice, CAMP gene expression was quantified by real-time PCR. CAMP gene expression was considerably increased in 3T3-L1 and SGBS adipocytes during differentiation. TNFα significantly induced CAMP gene expression in mature adipocytes, which was effectively antagonized by inhibition of PI3K signaling. Cell-free nucleic acids (cfDNA) significantly impaired CAMP gene expression, whereas synthetic agonistic and antagonistic TLR9 ligands had no effect. CAMP and TLR9 gene expression were correlated positively in murine and human subcutaneous but not in intra-abdominal/visceral adipose tissues. Male TLR9 knockout mice exhibited lower systemic CAMP concentrations than wildtype mice. CAMP gene expression levels in primary adipocytes did not significantly differ between wildtype and TLR9 KO mice. These findings suggest a regulatory role of inflammatory mediators, such as TNFα and cfDNA, in adipocytic CAMP expression as a novel putative molecular mechanism in adipose tissue innate immunity.


Assuntos
Ácidos Nucleicos Livres , Receptor Toll-Like 9 , Masculino , Camundongos , Humanos , Animais , Receptor Toll-Like 9/genética , Receptor Toll-Like 9/metabolismo , Catelicidinas/genética , Catelicidinas/farmacologia , Catelicidinas/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Adipócitos/metabolismo , Inflamação/metabolismo , Obesidade/genética , Obesidade/metabolismo , Expressão Gênica , Ácidos Nucleicos Livres/metabolismo , Regulação da Expressão Gênica , Células 3T3-L1
11.
Artigo em Alemão | MEDLINE | ID: mdl-37535086

RESUMO

BACKGROUND: The main framework conditions for palliative care are set at the regional level. The scope of the forms of care used (outpatient, inpatient, general, specialized) varies widely. What is the quality of outcomes achieved by the palliative care provided on a federal states level? What are the associated costs of care? METHOD: Retrospective observational study using BARMER claims data from 145,372 individuals who died between 2016 and 2019 and had palliative care in the last year of life. Regional comparison with regard to the following outcomes: proportion of palliative care patients who died in the hospital, potentially burdensome care in the last 30 days of life (ambulance calls, [intensive care] hospitalizations, chemotherapy, feeding tubes, parenteral nutrition), total cost of care (last three months), cost of palliative care (last year), and cost-effectiveness ratios. Calculation of patient/resident characteristic adjusted rates, costs, and ratios. RESULTS: Federal states vary significantly with respect to the outcomes (also adjusted) of palliative care. Palliative care costs vary widely, most strongly for specialized outpatient palliative care (SAPV). Across all indicators and the cost-effectiveness ratio of total cost of care to at-home deaths, Westphalia-Lippe shows favorable results. CONCLUSION: Regions with better quality and more favorable cost (ratios) can provide guidance for other regions. The extent to which the new federal SAPV agreement can incorporate the empirical findings should be reviewed. Patient-relevant outcome parameters should be given greater weight than parameters aiming at structures of care.


Assuntos
Cuidados Paliativos , Assistência Terminal , Humanos , Alemanha/epidemiologia , Assistência Ambulatorial , Hospitalização , Estudos Retrospectivos
12.
Biospektrum (Heidelb) ; 29(3): 306-309, 2023.
Artigo em Alemão | MEDLINE | ID: mdl-37275943

RESUMO

Recent progress in algal biotechnology has identified new products based on their broad evolutionary origin. Novel metabolites were found for pharmacy, food industry, medicine e.g. tumor suppression and antibiotics. However, sustainable and economical algal production for crude oil replacement is limited by extremely low space time yields in photobioreactors. The consequences are a high energy burden for mass flow dependent processes and the need of space being in conflict with sustainable landscape management. New concepts using algae not as biomass producers but as living catalysts may open new options.

13.
Appl Environ Microbiol ; 88(8): e0006322, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35369703

RESUMO

Cyanobacteria are considered promising hosts for product synthesis directly from CO2 via photosynthetic carbon assimilation. The introduction of heterologous carbon sinks in terms of product synthesis has been reported to induce the so-called "carbon sink effect," described as the release of unused photosynthetic capacity by the introduction of additional carbon. This effect is thought to arise from a limitation of carbon metabolism that represents a bottleneck in carbon and electron flow, thus enforcing a downregulation of photosynthetic efficiency. It is not known so far how the cellular source/sink balance under different growth conditions influences the extent of the carbon sink effect and in turn product formation from CO2, constituting a heterologous carbon sink. We compared the Synechocystis sp. strain PCC 6803 wild type (WT) with an engineered lactate-producing strain (SAA023) in defined metabolic states. Unexpectedly, high-light conditions combined with carbon limitation enabled additional carbon assimilation for lactate production without affecting biomass formation. Thus, a strong carbon sink effect only was observed under carbon and thus sink limitation, but not under high-sink conditions. We show that the carbon sink effect was accompanied by an increased rate of alternative electron flow (AEF). Thus, AEF plays a crucial role in the equilibration of source/sink imbalances, presumably via ATP/NADPH balancing. This study emphasizes that the evaluation of the biotechnological potential of cyanobacteria profits from cultivation approaches enabling the establishment of defined metabolic states and respective quantitative analytics. Factors stimulating photosynthesis and carbon fixation are discussed. IMPORTANCE Previous studies reported various and differing effects of the heterologous production of carbon-based molecules on photosynthetic and growth efficiency of cyanobacteria. The typically applied cultivation in batch mode, with continuously changing growth conditions, however, precludes a clear differentiation between the impact of cultivation conditions on cell physiology and effects related to the specific nature of the product and its synthesis pathway. In this study, we employed a continuous cultivation system to maintain defined source/sink conditions and thus metabolic states. This allowed a systematic and quantitative analysis of the effect of NADPH-consuming lactate production on photosynthetic and growth efficiency. This approach enables a realistic evaluation of the biotechnological potential of engineered cyanobacterial strains. For example, the quantum requirement for carbon production was found to constitute an excellent indicator of the source/sink balance and thus a key parameter for photobioprocess optimization. Such knowledge is fundamental for rational and efficient strain and process development.


Assuntos
Synechocystis , Carbono/metabolismo , Dióxido de Carbono/metabolismo , Sequestro de Carbono , Lactatos/metabolismo , NADP/metabolismo , Synechocystis/metabolismo
14.
Eur J Nutr ; 61(4): 1919-1929, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34951653

RESUMO

BACKGROUND: The postprandial regulation of angiopoietin-like proteins (Angptls) and their expression in adipocytes is poorly characterized. OBJECTIVE: Circulating Angptl3 and 4 were analyzed in healthy individuals undergoing either an oral lipid tolerance test (OLTT; n = 98) or an oral glucose tolerance test (OGTT; n = 99). Venous blood was drawn after 0, 2, 4, and 6 h during OLTT and after 0, 1, and 2 h during OGTT. Anthropometric and laboratory parameters were assessed and concentrations of Angptls were quantified by enzyme-linked immunosorbent assay. Angptl gene expression in 3T3-L1 adipocytes and in murine adipose tissues and cellular fractions was analyzed by quantitative real-time PCR. RESULTS: Angptl3 concentrations significantly decreased while Angptl4 levels continuously increased during OLTT. Both proteins remained unaffected during OGTT. Angptl3 and Angptl4 were expressed in murine subcutaneous and visceral AT with higher mRNA levels in mature adipocytes when compared to the stroma-vascular cell fraction. Both proteins were strongly induced during 3T3-L1 adipocyte differentiation and they were unresponsive to glucose in mature fat cells. Adipocyte Angptl3 (but not Angptl4) mRNA expression was inhibited by the polyunsaturated fatty acids arachidonic acid and docosahexaenoic acid, whereas nine types of dietary fatty acids remained without any effect. CONCLUSIONS: There is evidence of short-time regulation of Angptl3/4 levels upon metabolic stress. Angptl4 expression is high and Angptl3 expression is low in AT and restricted mainly to mature adipocytes without any differences concerning fat compartments. Whereas dietary fatty acids and glucose are without any effect, omega-3/-6-polyunsaturated fatty acids inhibited Anptl3 expression in adipocytes.


Assuntos
Proteína 3 Semelhante a Angiopoietina , Glucose , Proteínas Semelhantes a Angiopoietina/genética , Proteínas Semelhantes a Angiopoietina/metabolismo , Animais , Ácidos Graxos , Teste de Tolerância a Glucose , Humanos , Camundongos , RNA Mensageiro
15.
Int J Mol Sci ; 23(22)2022 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-36430499

RESUMO

Allocation of morbidly obese patients to either conservative therapy options-such as lifestyle intervention and/or low-calorie diet (LCD)-or to bariatric surgery-preferably sleeve gastrectomy or Roux-en-Y gastric bypass (RYGB)-represents a crucial decision in order to obtain sustainable metabolic improvement and weight loss. The present study encompasses 160 severely obese patients, 81 of whom participated in an LCD program, whereas 79 underwent RYGB surgery. The post-interventional dynamics of physiologically relevant adipokines and hepatokines (ANGPTL4, CCL5, GDF15, GPNMB, IGFBP6), as well as their correlation with fat mass reduction and improvement of liver fibrosis, were analyzed. Systemic GDF15 was characterized as an excellent predictive marker for hepatic fibrosis as well as type 2 diabetes mellitus. Of note, baseline GDF15 serum concentrations were positively correlated with NFS and HbA1c levels after correction for BMI, suggesting GDF15 as a BMI-independent marker of hepatic fibrosis and T2D in obese individuals. Specific GDF15 cut-off values for both diseases were calculated. Overall, the present data demonstrate that circulating levels of specific adipokines and hepatokines are regulated with therapy-induced fat loss and metabolic improvement and might, therefore, serve as biomarkers for the success of obesity therapy strategies.


Assuntos
Diabetes Mellitus Tipo 2 , Derivação Gástrica , Obesidade Mórbida , Humanos , Obesidade Mórbida/diagnóstico , Obesidade Mórbida/cirurgia , Adipocinas , Diabetes Mellitus Tipo 2/etiologia , Biomarcadores , Cirrose Hepática/diagnóstico , Cirrose Hepática/terapia , Cirrose Hepática/etiologia , Glicoproteínas de Membrana
16.
Int J Mol Sci ; 23(15)2022 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-35955609

RESUMO

Endosome-localized Toll-like receptors (TLRs) 3 and 9 are expressed and functionally active in adipocytes. The functionality and role of TLR7 in adipocyte biology and innate immunity of adipose tissue (AT) is poorly characterized. We analyzed TLR7 mRNA and protein expression in murine 3T3-L1 and primary adipocytes, in co-cultures of 3T3-L1 adipocytes with murine J774A.1 monocytes and in human AT. The effects of TLR7 agonists imiquimod (IMQ) and cell-free nucleic acids (cfDNA) on adipokine concentration in cell-culture supernatants and gene expression profile were investigated. We found that TLR7 expression is strongly induced during adipocyte differentiation. TLR7 gene expression in adipocytes and AT stroma-vascular cells (SVC) seems to be independent of TLR9. IMQ downregulates resistin concentration in adipocyte cell-culture supernatants and modulates gene expression of glucose transporter Glut4. Adipocyte-derived cfDNA reduces adiponectin and resistin in cell-culture supernatants and potentially inhibits Glut4 gene expression. The responsiveness of 3T3-L1 adipocytes to imiquimod is preserved in co-culture with J774A.1 monocytes. Obesity-related, adipocyte-derived cfDNA engages adipocytic pattern recognition receptors (PRRs), modulating AT immune and metabolic homeostasis during adipose inflammation.


Assuntos
Ácidos Nucleicos Livres , Resistina , Células 3T3-L1 , Adipócitos/metabolismo , Adjuvantes Imunológicos/farmacologia , Animais , Diferenciação Celular/genética , Ácidos Nucleicos Livres/metabolismo , Humanos , Imiquimode/farmacologia , Camundongos , Resistina/metabolismo , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/metabolismo
17.
Angew Chem Int Ed Engl ; 61(29): e202204098, 2022 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-35511505

RESUMO

Improving the performance of chemical transformations catalysed by microbial biocatalysts requires a deep understanding of cellular processes. While the cellular heterogeneity of cellular characteristics, such as the concentration of high abundant cellular content, is well studied, little is known about the reactivity of individual cells and its impact on the chemical identity, quantity, and purity of excreted products. Biocatalytic transformations were monitored chemically specific and quantifiable at the single-cell level by integrating droplet microfluidics, cell imaging, and mass spectrometry. Product formation rates for individual Saccharomyces cerevisiae cells were obtained by i) incubating nanolitre-sized droplets for product accumulation in microfluidic devices, ii) an imaging setup to determine the number of cells in the droplets, and iii) electrospray ionisation mass spectrometry for reading the chemical contents of individual droplets. These findings now enable the study of whole-cell biocatalysis at single-cell resolution.


Assuntos
Técnicas Analíticas Microfluídicas , Microfluídica , Biocatálise , Dispositivos Lab-On-A-Chip , Microfluídica/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos
18.
Metab Eng ; 68: 199-209, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34673236

RESUMO

Molecular hydrogen (H2) is considered as an ideal energy carrier to replace fossil fuels in future. Biotechnological H2 production driven by oxygenic photosynthesis appears highly promising, as biocatalyst and H2 syntheses rely mainly on light, water, and CO2 and not on rare metals. This biological process requires coupling of the photosynthetic water oxidizing apparatus to a H2-producing hydrogenase. However, this strategy is impeded by the simultaneous release of oxygen (O2) which is a strong inhibitor of most hydrogenases. Here, we addressed this challenge, by the introduction of an O2-tolerant hydrogenase into phototrophic bacteria, namely the cyanobacterial model strain Synechocystis sp. PCC 6803. To this end, the gene cluster encoding the soluble, O2-tolerant, and NAD(H)-dependent hydrogenase from Ralstonia eutropha (ReSH) was functionally transferred to a Synechocystis strain featuring a knockout of the native O2 sensitive hydrogenase. Intriguingly, photosynthetically active cells produced the O2 tolerant ReSH, and activity was confirmed in vitro and in vivo. Further, ReSH enabled the constructed strain Syn_ReSH+ to utilize H2 as sole electron source to fix CO2. Syn_ReSH+ also was able to produce H2 under dark fermentative conditions as well as in presence of light, under conditions fostering intracellular NADH excess. These findings highlight a high level of interconnection between ReSH and cyanobacterial redox metabolism. This study lays a foundation for further engineering, e.g., of electron transfer to ReSH via NADPH or ferredoxin, to finally enable photosynthesis-driven H2 production.


Assuntos
Hidrogenase , Synechocystis , Hidrogênio , Hidrogenase/genética , Oxigênio , Fotossíntese , Synechocystis/genética , Synechocystis/metabolismo
19.
Cytokine ; 148: 155663, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34388476

RESUMO

BACKGROUND AND AIM: CAMP (Cathelicidin antimicrobial peptide) expression in adipocytes is regulated by Toll-like receptor (TLR) agonists. Secreted adipokines such as CTRP-3 have been suggested to participate in innate immune signaling in adipose tissue (AT). This study investigates whether TLR-induced CAMP expression in adipocytes is antagonized by CTRP-3. METHODS: 3T3-L1 adipocytes were co-stimulated with TLR agonists (LPS, MALP-2, Pam3CSK4, pI:C) and recombinant CTRP-3. In a SIRS model, C57BL/6 wild-type mice were intraperitoneally (ip) injected with recombinant CTRP-3 prior to LPS. CAMP expression was analyzed by real-time PCR in AT of wild-type mice and in AT and primary adipocytes from transgenic mice lacking adipocyte CTRP-3 expression. Comparative transcriptome analysis by RNA seq. was applied in CTRP-3 KO adipocytes. RESULTS: In vitro, CTRP-3 antagonized TLR4- and TLR1/2-induced CAMP expression in adipocytes whereas TLR3- and TLR2/6-mediated induction of CAMP was not affected. in vivo, application of exogenous CTRP-3 dose-dependently antagonized LPS-induced CAMP expression in intra-abdominal AT. CAMP expression in total AT and in primary adipocytes of subcutaneous and intra-abdominal AT did not differ between wild-type mice and transgenic mice lacking adipocyte CTRP-3 expression. CONCLUSIONS: The study suggests a hypothetical role of CAMP in host defense not only against Gram-positive bacteria sensed by TLR1/2 and TLR2/6 but also against Gram-negative bacteria sensed by TLR4 and potentially against viruses sensed by TLR3. The machinery of TLR-mediated pro-inflammatory activation of the CAMP gene in adipocytes seems to be partly modulated by secreted adipokines belonging to the growing family of C1q/TNF-related proteins such as CTRP-3.


Assuntos
Adipócitos/metabolismo , Adipocinas/metabolismo , Peptídeos Antimicrobianos/genética , Regulação da Expressão Gênica , Receptores Toll-Like/metabolismo , Células 3T3-L1 , Adipocinas/deficiência , Tecido Adiposo/metabolismo , Animais , Peptídeos Antimicrobianos/metabolismo , Modelos Animais de Doenças , Lipopolissacarídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Biológicos , Síndrome de Resposta Inflamatória Sistêmica/genética , Transcriptoma/genética
20.
Phys Rev Lett ; 127(12): 127203, 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34597075

RESUMO

It has been shown previously that the presence of a Dzyaloshinskii-Moriya interaction in perpendicularly magnetized thin films stabilizes Néel type domain walls. We demonstrate, using micromagnetic simulations and analytical modeling, that the presence of a uniaxial in plane magnetic anisotropy can also lead to the formation of Néel walls in the absence of a Dzyaloshinskii-Moriya interaction. It is possible to abruptly switch between Bloch and Néel walls via a small modulation of the in plane, but also the perpendicular, magnetic anisotropy. This opens up a route toward electric field control of the domain wall type with small applied voltages through electric field controlled anisotropies.

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