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1.
Nat Immunol ; 21(7): 736-745, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32367036

RESUMEN

Cytosolic sensing of pathogens and damage by myeloid and barrier epithelial cells assembles large complexes called inflammasomes, which activate inflammatory caspases to process cytokines (IL-1ß) and gasdermin D (GSDMD). Cleaved GSDMD forms membrane pores, leading to cytokine release and inflammatory cell death (pyroptosis). Inhibiting GSDMD is an attractive strategy to curb inflammation. Here we identify disulfiram, a drug for treating alcohol addiction, as an inhibitor of pore formation by GSDMD but not other members of the GSDM family. Disulfiram blocks pyroptosis and cytokine release in cells and lipopolysaccharide-induced septic death in mice. At nanomolar concentration, disulfiram covalently modifies human/mouse Cys191/Cys192 in GSDMD to block pore formation. Disulfiram still allows IL-1ß and GSDMD processing, but abrogates pore formation, thereby preventing IL-1ß release and pyroptosis. The role of disulfiram in inhibiting GSDMD provides new therapeutic indications for repurposing this safe drug to counteract inflammation, which contributes to many human diseases.


Asunto(s)
Disulfiram/farmacología , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Proteínas de Unión a Fosfato/antagonistas & inhibidores , Piroptosis/efectos de los fármacos , Sepsis/tratamiento farmacológico , Animales , Caspasa 1/genética , Caspasa 1/metabolismo , Inhibidores de Caspasas/farmacología , Caspasas/metabolismo , Caspasas Iniciadoras/genética , Caspasas Iniciadoras/metabolismo , Línea Celular Tumoral , Disulfiram/uso terapéutico , Evaluación Preclínica de Medicamentos , Reposicionamiento de Medicamentos , Femenino , Células HEK293 , Ensayos Analíticos de Alto Rendimiento , Humanos , Interleucina-1beta/inmunología , Interleucina-1beta/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Lipopolisacáridos/administración & dosificación , Lipopolisacáridos/inmunología , Liposomas , Ratones , Mutagénesis Sitio-Dirigida , Proteínas de Unión a Fosfato/genética , Proteínas de Unión a Fosfato/metabolismo , Piroptosis/inmunología , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sepsis/inmunología , Células Sf9 , Spodoptera
2.
Immunity ; 56(2): 336-352.e9, 2023 02 14.
Artículo en Inglés | MEDLINE | ID: mdl-36792573

RESUMEN

The physiological and immune changes that occur during pregnancy are associated with worsened disease outcomes during infection and sepsis. How these perturbations exacerbate inflammation has not been explored. Here, using antibiotic treatment and fecal microbial transfers, we showed that sepsis susceptibility is driven by pregnancy-induced changes to gut microbiome in mice and humans. Integrative multiomics and genetically engineered bacteria revealed that reduced Parabacteroides merdae (P. merdae) abundance during pregnancy led to decreased formononetin (FMN) and increased macrophage death. Mechanistically, FMN inhibited macrophage pyroptosis by suppressing nuclear accumulation of hnRNPUL2 and subsequent binding to the Nlrp3 promoter. Treatment with FMN or deletion of murine hnRNPUL2 protected against septic inflammation. Intestinal abundances of P. merdae and FMN inversely correlated with the progression of septic patients. Our data reveal a microbe-immune axis that is disrupted in pregnant septic hosts, highlighting the potential of the FMN-hnRNPUL2-NLRP3 axis in providing promising therapeutic strategies for sepsis.


Asunto(s)
Microbioma Gastrointestinal , Sepsis , Embarazo , Femenino , Humanos , Animales , Ratones , Microbioma Gastrointestinal/fisiología , Piroptosis/fisiología , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Macrófagos/metabolismo , Sepsis/metabolismo , Inflamación/metabolismo
3.
Immunity ; 54(3): 454-467.e6, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-33561388

RESUMEN

Heparin, a mammalian polysaccharide, is a widely used anticoagulant medicine to treat thrombotic disorders. It is also known to improve outcomes in sepsis, a leading cause of mortality resulted from infection-induced immune dysfunction. Whereas it is relatively clear how heparin exerts its anticoagulant effect, the immunomodulatory mechanisms enabled by heparin remain enigmatic. Here, we show that heparin prevented caspase-11-dependent immune responses and lethality in sepsis independent of its anticoagulant properties. Heparin or a chemically modified form of heparin without anticoagulant function inhibited the alarmin HMGB1-lipopolysaccharide (LPS) interaction and prevented the macrophage glycocalyx degradation by heparanase. These events blocked the cytosolic delivery of LPS in macrophages and the activation of caspase-11, a cytosolic LPS receptor that mediates lethality in sepsis. Survival was higher in septic patients treated with heparin than those without heparin treatment. The identification of this previously unrecognized heparin function establishes a link between innate immune responses and coagulation.


Asunto(s)
Anticoagulantes/uso terapéutico , Caspasas/metabolismo , Heparina/uso terapéutico , Macrófagos/inmunología , Sepsis/tratamiento farmacológico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Caspasas/genética , Línea Celular , Femenino , Glucuronidasa/genética , Glucuronidasa/metabolismo , Glicocálix/metabolismo , Proteína HMGB1/metabolismo , Humanos , Inmunomodulación , Lipopolisacáridos/metabolismo , Masculino , Ratones , Ratones Noqueados , Persona de Mediana Edad , Sepsis/mortalidad , Análisis de Supervivencia , Adulto Joven
4.
Nature ; 630(8016): 484-492, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38811729

RESUMEN

The CRISPR system is an adaptive immune system found in prokaryotes that defends host cells against the invasion of foreign DNA1. As part of the ongoing struggle between phages and the bacterial immune system, the CRISPR system has evolved into various types, each with distinct functionalities2. Type II Cas9 is the most extensively studied of these systems and has diverse subtypes. It remains uncertain whether members of this family can evolve additional mechanisms to counter viral invasions3,4. Here we identify 2,062 complete Cas9 loci, predict the structures of their associated proteins and reveal three structural growth trajectories for type II-C Cas9. We found that novel associated genes (NAGs) tended to be present within the loci of larger II-C Cas9s. Further investigation revealed that CbCas9 from Chryseobacterium species contains a novel ß-REC2 domain, and forms a heterotetrameric complex with an NAG-encoded CRISPR-Cas-system-promoting (pro-CRISPR) protein of II-C Cas9 (PcrIIC1). The CbCas9-PcrIIC1 complex exhibits enhanced DNA binding and cleavage activity, broader compatibility for protospacer adjacent motif sequences, increased tolerance for mismatches and improved anti-phage immunity, compared with stand-alone CbCas9. Overall, our work sheds light on the diversity and 'growth evolutionary' trajectories of II-C Cas9 proteins at the structural level, and identifies many NAGs-such as PcrIIC1, which serves as a pro-CRISPR factor to enhance CRISPR-mediated immunity.


Asunto(s)
Bacterias , Bacteriófagos , Proteína 9 Asociada a CRISPR , Sistemas CRISPR-Cas , Bacterias/virología , Bacterias/genética , Bacterias/inmunología , Bacteriófagos/genética , Bacteriófagos/inmunología , Chryseobacterium/genética , Chryseobacterium/inmunología , Chryseobacterium/virología , Proteína 9 Asociada a CRISPR/química , Proteína 9 Asociada a CRISPR/genética , Proteína 9 Asociada a CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , Sistemas CRISPR-Cas/inmunología , División del ADN , Sitios Genéticos/genética , Modelos Moleculares , Dominios Proteicos
5.
Nature ; 623(7987): 531-537, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37853122

RESUMEN

Achieving both high efficiency and long-term stability is the key to the commercialization of perovskite solar cells (PSCs)1,2. However, the diversity of perovskite (ABX3) compositions and phases makes it challenging to fabricate high-quality films3-5. Perovskite formation relies on the reaction between AX and BX2, whereas most conventional methods for film-growth regulation are based solely on the interaction with the BX2 component. Herein, we demonstrate an alternative approach to modulate reaction kinetics by anion-π interaction between AX and hexafluorobenzene (HFB). Notably, these two approaches are independent but work together to establish 'dual-site regulation', which achieves a delicate control over the reaction between AX and BX2 without unwanted intermediates. The resultant formamidinium lead halides (FAPbI3) films exhibit fewer defects, redshifted absorption and high phase purity without detectable nanoscale δ phase. Consequently, we achieved PSCs with power conversion efficiency (PCE) up to 26.07% for a 0.08-cm2 device (25.8% certified) and 24.63% for a 1-cm2 device. The device also kept 94% of its initial PCE after maximum power point (MPP) tracking for 1,258 h under full-spectrum AM 1.5 G sunlight at 50 ± 5 °C. This method expands the range of chemical interactions that occur in perovskite precursors by exploring anion-π interactions and highlights the importance of the AX component as a new and effective working site to improved photovoltaic devices with high quality and phase purity.

6.
Nature ; 619(7969): 288-292, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37438595

RESUMEN

The occurrence of superconductivity in proximity to various strongly correlated phases of matter has drawn extensive focus on their normal state properties, to develop an understanding of the state from which superconductivity emerges1-4. The recent finding of superconductivity in layered nickelates raises similar interests5-8. However, transport measurements of doped infinite-layer nickelate thin films have been hampered by materials limitations of these metastable compounds: in particular, a high density of extended defects9-11. Here, by moving to a substrate (LaAlO3)0.3(Sr2TaAlO6)0.7 that better stabilizes the growth and reduction conditions, we can synthesize the doping series of Nd1-xSrxNiO2 essentially free from extended defects. In their absence, the normal state resistivity shows a low-temperature upturn in the underdoped regime, linear behaviour near optimal doping and quadratic temperature dependence for overdoping. This is phenomenologically similar to the copper oxides2,12 despite key distinctions-namely, the absence of an insulating parent compound5,6,9,10, multiband electronic structure13,14 and a Mott-Hubbard orbital alignment rather than the charge-transfer insulator of the copper oxides15,16. We further observe an enhancement of superconductivity, both in terms of transition temperature and range of doping. These results indicate a convergence in the electronic properties of both superconducting families as the scale of disorder in the nickelates is reduced.

7.
Nature ; 602(7897): 496-502, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-35110732

RESUMEN

Gasdermins, a family of five pore-forming proteins (GSDMA-GSDME) in humans expressed predominantly in the skin, mucosa and immune sentinel cells, are key executioners of inflammatory cell death (pyroptosis), which recruits immune cells to infection sites and promotes protective immunity1,2. Pore formation is triggered by gasdermin cleavage1,2. Although the proteases that activate GSDMB, C, D and E have been identified, how GSDMA-the dominant gasdermin in the skin-is activated, remains unknown. Streptococcus pyogenes, also known as group A Streptococcus (GAS), is a major skin pathogen that causes substantial morbidity and mortality worldwide3. Here we show that the GAS cysteine protease SpeB virulence factor triggers keratinocyte pyroptosis by cleaving GSDMA after Gln246, unleashing an active N-terminal fragment that triggers pyroptosis. Gsdma1 genetic deficiency blunts mouse immune responses to GAS, resulting in uncontrolled bacterial dissemination and death. GSDMA acts as both a sensor and substrate of GAS SpeB and as an effector to trigger pyroptosis, adding a simple one-molecule mechanism for host recognition and control of virulence of a dangerous microbial pathogen.


Asunto(s)
Exotoxinas , Piroptosis , Animales , Proteínas Bacterianas/metabolismo , Exotoxinas/genética , Exotoxinas/metabolismo , Ratones , Streptococcus pyogenes
8.
Nature ; 604(7904): 72-79, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35388196

RESUMEN

Covalent organic frameworks (COFs) are distinguished from other organic polymers by their crystallinity1-3, but it remains challenging to obtain robust, highly crystalline COFs because the framework-forming reactions are poorly reversible4,5. More reversible chemistry can improve crystallinity6-9, but this typically yields COFs with poor physicochemical stability and limited application scope5. Here we report a general and scalable protocol to prepare robust, highly crystalline imine COFs, based on an unexpected framework reconstruction. In contrast to standard approaches in which monomers are initially randomly aligned, our method involves the pre-organization of monomers using a reversible and removable covalent tether, followed by confined polymerization. This reconstruction route produces reconstructed COFs with greatly enhanced crystallinity and much higher porosity by means of a simple vacuum-free synthetic procedure. The increased crystallinity in the reconstructed COFs improves charge carrier transport, leading to sacrificial photocatalytic hydrogen evolution rates of up to 27.98 mmol h-1 g-1. This nanoconfinement-assisted reconstruction strategy is a step towards programming function in organic materials through atomistic structural control.

9.
Proc Natl Acad Sci U S A ; 121(4): e2314454121, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38232283

RESUMEN

The discoveries of ferromagnetism down to the atomically thin limit in van der Waals (vdW) crystals by mechanical exfoliation have enriched the family of magnetic thin films [C. Gong et al., Nature 546, 265-269 (2017) and B. Huang et al., Nature 546, 270-273 (2017)]. However, compared to the study of traditional magnetic thin films by physical deposition methods, the toolbox of the vdW crystals based on mechanical exfoliation and transfer suffers from low yield and ambient corrosion problem and now is facing new challenges to study magnetism. For example, the formation of magnetic superlattice is difficult in vdW crystals, which limits the study of the interlayer interaction in vdW crystals [M. Gibertini, M. Koperski, A. F. Morpurgo, K. S. Novoselov, Nat. Nanotechnol. 14, 408-419 (2019)]. Here, we report a strategy of interlayer engineering of the magnetic vdW crystal Fe3GeTe2 (FGT) by intercalating quaternary ammonium cations into the vdW spacing. Both three-dimensional (3D) vdW superlattice and two-dimensional (2D) vdW monolayer can be formed by using this method based on the amount of intercalant. On the one hand, the FGT superlattice shows a strong 3D critical behavior with a decreased coercivity and increased domain wall size, attributed to the co-engineering of the anisotropy, exchange interaction, and electron doping by intercalation. On the other hand, the 2D vdW few layers obtained by over-intercalation are capped with organic molecules from the bulk crystal, which not only enhances the ferromagnetic transition temperature (TC), but also substantially protects the thin samples from degradation, thus allowing the preparation of large-scale FGT ink in ambient environment.

10.
Nature ; 583(7815): 237-241, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32641813

RESUMEN

Technologies such as batteries, biomaterials and heterogeneous catalysts have functions that are defined by mixtures of molecular and mesoscale components. As yet, this multi-length-scale complexity cannot be fully captured by atomistic simulations, and the design of such materials from first principles is still rare1-5. Likewise, experimental complexity scales exponentially with the number of variables, restricting most searches to narrow areas of materials space. Robots can assist in experimental searches6-14 but their widespread adoption in materials research is challenging because of the diversity of sample types, operations, instruments and measurements required. Here we use a mobile robot to search for improved photocatalysts for hydrogen production from water15. The robot operated autonomously over eight days, performing 688 experiments within a ten-variable experimental space, driven by a batched Bayesian search algorithm16-18. This autonomous search identified photocatalyst mixtures that were six times more active than the initial formulations, selecting beneficial components and deselecting negative ones. Our strategy uses a dexterous19,20 free-roaming robot21-24, automating the researcher rather than the instruments. This modular approach could be deployed in conventional laboratories for a range of research problems beyond photocatalysis.

11.
Proc Natl Acad Sci U S A ; 120(31): e2306399120, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37487070

RESUMEN

Toll-like receptor 4 (TLR4) sensing of lipopolysaccharide (LPS), the most potent pathogen-associated molecular pattern of gram-negative bacteria, activates NF-κB and Irf3, which induces inflammatory cytokines and interferons that trigger an intense inflammatory response, which is critical for host defense but can also cause serious inflammatory pathology, including sepsis. Although TLR4 inhibition is an attractive therapeutic approach for suppressing overexuberant inflammatory signaling, previously identified TLR4 antagonists have not shown any clinical benefit. Here, we identify disulfiram (DSF), an FDA-approved drug for alcoholism, as a specific inhibitor of TLR4-mediated inflammatory signaling. TLR4 cell surface expression, LPS sensing, dimerization and signaling depend on TLR4 binding to MD-2. DSF and other cysteine-reactive drugs, previously shown to block LPS-triggered inflammatory cell death (pyroptosis), inhibit TLR4 signaling by covalently modifying Cys133 of MD-2, a key conserved residue that mediates TLR4 sensing and signaling. DSF blocks LPS-triggered inflammatory cytokine, chemokine, and interferon production by macrophages in vitro. In the aggressive N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease (PD) in which TLR4 plays an important role, DSF markedly suppresses neuroinflammation and dopaminergic neuron loss, and restores motor function. Our findings identify a role for DSF in curbing TLR4-mediated inflammation and suggest that DSF and other drugs that target MD-2 might be useful for treating PD and other diseases in which inflammation contributes importantly to pathogenesis.


Asunto(s)
Alcoholismo , Disulfiram , Animales , Ratones , Receptor Toll-Like 4 , Lipopolisacáridos , Transducción de Señal , Citocinas
12.
Proc Natl Acad Sci U S A ; 120(14): e2300439120, 2023 04 04.
Artículo en Inglés | MEDLINE | ID: mdl-36996102

RESUMEN

Ongoing host-pathogen interactions can trigger a coevolutionary arms race, while genetic diversity within the host can facilitate its adaptation to pathogens. Here, we used the diamondback moth (Plutella xylostella) and its pathogen Bacillus thuringiensis (Bt) as a model for exploring an adaptive evolutionary mechanism. We found that insect host adaptation to the primary Bt virulence factors was tightly associated with a short interspersed nuclear element (SINE - named SE2) insertion into the promoter of the transcriptionally activated MAP4K4 gene. This retrotransposon insertion coopts and potentiates the effect of the transcription factor forkhead box O (FOXO) in inducing a hormone-modulated Mitogen-activated protein kinase (MAPK) signaling cascade, leading to an enhancement of a host defense mechanism against the pathogen. This work demonstrates that reconstructing a cis-trans interaction can escalate a host response mechanism into a more stringent resistance phenotype to resist pathogen infection, providing a new insight into the coevolutionary mechanism of host organisms and their microbial pathogens.


Asunto(s)
Bacillus thuringiensis , Mariposas Nocturnas , Animales , Endotoxinas/farmacología , Retroelementos/genética , Mariposas Nocturnas/metabolismo , Bacillus thuringiensis/metabolismo , Toxinas de Bacillus thuringiensis/metabolismo , Resistencia a los Insecticidas/genética , Larva/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas Hemolisinas/metabolismo
13.
Circulation ; 150(11): 867-883, 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-38804138

RESUMEN

BACKGROUND: Pulmonary hypertension (PH) is a major complication linked to adverse outcomes in heart failure with preserved ejection fraction (HFpEF), yet no specific therapies exist for PH associated with HFpEF (PH-HFpEF). We have recently reported on the role of skeletal muscle SIRT3 (sirtuin-3) in modulation of PH-HFpEF, suggesting a novel endocrine signaling pathway for skeletal muscle modulation of pulmonary vascular remodeling. METHODS: Using skeletal muscle-specific Sirt3 knockout mice (Sirt3skm-/-) and mass spectrometry-based comparative secretome analysis, we attempted to define the processes by which skeletal muscle SIRT3 defects affect pulmonary vascular health in PH-HFpEF. RESULTS: Sirt3skm-/- mice exhibited reduced pulmonary vascular density accompanied by pulmonary vascular proliferative remodeling and elevated pulmonary pressures. Comparative analysis of secretome by mass spectrometry revealed elevated secretion levels of LOXL2 (lysyl oxidase homolog 2) in SIRT3-deficient skeletal muscle cells. Elevated circulation and protein expression levels of LOXL2 were also observed in plasma and skeletal muscle of Sirt3skm-/- mice, a rat model of PH-HFpEF, and humans with PH-HFpEF. In addition, expression levels of CNPY2 (canopy fibroblast growth factor signaling regulator 2), a known proliferative and angiogenic factor, were increased in pulmonary artery endothelial cells and pulmonary artery smooth muscle cells of Sirt3skm-/- mice and animal models of PH-HFpEF. CNPY2 levels were also higher in pulmonary artery smooth muscle cells of subjects with obesity compared with nonobese subjects. Moreover, treatment with recombinant LOXL2 protein promoted pulmonary artery endothelial cell migration/proliferation and pulmonary artery smooth muscle cell proliferation through regulation of CNPY2-p53 signaling. Last, skeletal muscle-specific Loxl2 deletion decreased pulmonary artery endothelial cell and pulmonary artery smooth muscle cell expression of CNPY2 and improved pulmonary pressures in mice with high-fat diet-induced PH-HFpEF. CONCLUSIONS: This study demonstrates a systemic pathogenic impact of skeletal muscle SIRT3 deficiency in remote pulmonary vascular remodeling and PH-HFpEF. This study suggests a new endocrine signaling axis that links skeletal muscle health and SIRT3 deficiency to remote CNPY2 regulation in the pulmonary vasculature through myokine LOXL2. Our data also identify skeletal muscle SIRT3, myokine LOXL2, and CNPY2 as potential targets for the treatment of PH-HFpEF.


Asunto(s)
Insuficiencia Cardíaca , Hipertensión Pulmonar , Ratones Noqueados , Músculo Esquelético , Sirtuina 3 , Volumen Sistólico , Remodelación Vascular , Animales , Sirtuina 3/metabolismo , Sirtuina 3/deficiencia , Sirtuina 3/genética , Insuficiencia Cardíaca/metabolismo , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/patología , Insuficiencia Cardíaca/etiología , Hipertensión Pulmonar/metabolismo , Hipertensión Pulmonar/fisiopatología , Hipertensión Pulmonar/etiología , Hipertensión Pulmonar/genética , Hipertensión Pulmonar/patología , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Músculo Esquelético/fisiopatología , Ratones , Humanos , Masculino , Ratas , Arteria Pulmonar/metabolismo , Arteria Pulmonar/patología , Arteria Pulmonar/fisiopatología , Modelos Animales de Enfermedad , Femenino
14.
Nat Mater ; 23(4): 543-551, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38278984

RESUMEN

Silicon is a promising anode material due to its high theoretical specific capacity, low lithiation potential and low lithium dendrite risk. Yet, the electrochemical performance of silicon anodes in solid-state batteries is still poor (for example, low actual specific capacity and fast capacity decay), hindering practical applications. Here the chemo-mechanical failure mechanisms of composite Si/Li6PS5Cl and solid-electrolyte-free silicon anodes are revealed by combining structural and chemical characterizations with theoretical simulations. The growth of the solid electrolyte interphase at the Si|Li6PS5Cl interface causes severe resistance increase in composite anodes, explaining their fast capacity decay. Solid-electrolyte-free silicon anodes show sufficient ionic and electronic conductivities, enabling a high specific capacity. However, microscale void formation during delithiation causes larger mechanical stress at the two-dimensional interfaces of these anodes than in composite anodes. Understanding these chemo-mechanical failure mechanisms of different anode architectures and the role of interphase formation helps to provide guidelines for the design of improved electrode materials.

15.
Nat Mater ; 23(6): 775-781, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38182811

RESUMEN

The discovery of superconductivity in infinite-layer nickelates established another category of unconventional superconductors that shares structural and electronic similarities with cuprates. However, key issues of the superconducting pairing symmetry, gap amplitude and superconducting fluctuations are yet to be addressed. Here we utilize static and ultrafast terahertz spectroscopy to address these. We demonstrate that the equilibrium terahertz conductivity and non-equilibrium terahertz responses of an optimally Sr-doped nickelate film (superconducting transition temperature of Tc = 17 K) are in line with the electrodynamics of d-wave superconductivity in the dirty limit. The gap-to-Tc ratio (2Δ/kBTc) is found to be 3.4, indicating that the superconductivity falls in the weak coupling regime. In addition, we observed substantial superconducting fluctuations near Tc that do not extend into the deep normal state as the optimally hole-doped cuprates do. Our results support a d-wave system that closely resembles the electron-doped cuprates.

16.
Plant Physiol ; 195(1): 566-579, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38345864

RESUMEN

The formation of multi-pistil flowers reduces the yield and quality in Japanese apricot (Prunus mume). However, the molecular mechanism underlying the formation of multi-pistil flowers remains unknown. In the current study, overexpression of PmKNAT2/6-a, a class I KNOTTED1-like homeobox (KNOX) member, in Arabidopsis (Arabidopsis thaliana) resulted in a multi-pistil phenotype. Analysis of the upstream regulators of PmKNAT2/6-a showed that AGAMOUS-like 24 (PmAGL24) could directly bind to the PmKNAT2/6-a promoter and regulate its expression. PmAGL24 also interacted with Like Heterochromatin Protein 1 (PmLHP1) to recruit lysine trimethylation at position 27 on histone H3 (H3K27me3) to regulate PmKNAT2/6-a expression, which is indirectly involved in multiple pistils formation in Japanese apricot flowers. Our study reveals that the PmAGL24 transcription factor, an upstream regulator of PmKNAT2/6-a, regulates PmKNAT2/6-a expression via direct and indirect pathways and is involved in the formation of multiple pistils in Japanese apricot.


Asunto(s)
Arabidopsis , Flores , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas , Flores/genética , Flores/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Plantas Modificadas Genéticamente , Prunus/genética , Prunus/metabolismo , Prunus armeniaca/genética , Prunus armeniaca/metabolismo , Regiones Promotoras Genéticas/genética
17.
FASEB J ; 38(16): e70014, 2024 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-39183544

RESUMEN

End-ischemic normothermic mechanical perfusion (NMP) could provide a curative treatment to reduce cholestatic liver injury from donation after circulatory death (DCD) in donors. However, the underlying mechanism remains elusive. Our previous study demonstrated that air-ventilated NMP could improve functional recovery of DCD in a preclinical NMP rat model. Here, metabolomics analysis revealed that air-ventilated NMP alleviated DCD- and cold preservation-induced cholestatic liver injury, as shown by the elevated release of alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, and γ-glutamyl transferase (GGT) in the perfusate (p < .05) and the reduction in the levels of bile acid metabolites, including ω-muricholic acid, glycohyodeoxycholic acid, glycocholic acid, and glycochenodeoxycholate (GCDC) in the perfused livers (p < .05). In addition, the expression of the key bile acid metabolism enzyme UDP-glucuronosyltransferase 1A1 (UGT1A1), which is predominantly expressed in hepatocytes, was substantially elevated in the DCD rat liver, followed by air-ventilated NMP (p < .05), and in vitro, this increase was induced by decreased GCDC and hypoxia-reoxygenation in the hepatic cells HepG2 and L02 (p < .05). Knockdown of UGT1A1 in hepatic cells by siRNA aggravated hepatic injury caused by GCDC and hypoxia-reoxygenation, as indicated by the ALT and AST levels in the supernatant. Mechanistically, UGT1A1 is transcriptionally regulated by peroxisome proliferator-activator receptor-γ (PPAR-γ) under hypoxia-physoxia. Taken together, our data revealed that air-ventilated NMP could alleviate DCD- and cold preservation-induced cholestatic liver injury through PPAR-γ/UGT1A1 axis. Based on the results from this study, air-ventilated NMP confers a promising approach for predicting and alleviating cholestatic liver injury through PPAR-γ/UGT1A1 axis.


Asunto(s)
PPAR gamma , Animales , Ratas , PPAR gamma/metabolismo , PPAR gamma/genética , Masculino , Humanos , Glucuronosiltransferasa/metabolismo , Glucuronosiltransferasa/genética , Hígado/metabolismo , Hígado/patología , Colestasis/metabolismo , Perfusión , Ratas Sprague-Dawley , Preservación de Órganos/métodos , Trasplante de Hígado
18.
Arterioscler Thromb Vasc Biol ; 44(7): 1570-1583, 2024 07.
Artículo en Inglés | MEDLINE | ID: mdl-38813697

RESUMEN

BACKGROUND: Pulmonary hypertension (PH) represents an important phenotype in heart failure with preserved ejection fraction (HFpEF). However, management of PH-HFpEF is challenging because mechanisms involved in the regulation of PH-HFpEF remain unclear. METHODS: We used a mass spectrometry-based comparative plasma proteomics approach as a sensitive and comprehensive hypothesis-generating discovery technique to profile proteins in patients with PH-HFpEF and control subjects. We then validated and investigated the role of one of the identified proteins using in vitro cell cultures, in vivo animal models, and independent cohort of human samples. RESULTS: Plasma proteomics identified high protein abundance levels of B2M (ß2-microglobulin) in patients with PH-HFpEF. Interestingly, both circulating and skeletal muscle levels of B2M were increased in mice with skeletal muscle SIRT3 (sirtuin-3) deficiency or high-fat diet-induced PH-HFpEF. Plasma and muscle biopsies from a validation cohort of PH-HFpEF patients were found to have increased B2M levels, which positively correlated with disease severity, especially pulmonary capillary wedge pressure and right atrial pressure at rest. Not only did the administration of exogenous B2M promote migration/proliferation in pulmonary arterial vascular endothelial cells but it also increased PCNA (proliferating cell nuclear antigen) expression and cell proliferation in pulmonary arterial vascular smooth muscle cells. Finally, B2m deletion improved glucose intolerance, reduced pulmonary vascular remodeling, lowered PH, and attenuated RV hypertrophy in mice with high-fat diet-induced PH-HFpEF. CONCLUSIONS: Patients with PH-HFpEF display higher circulating and skeletal muscle expression levels of B2M, the magnitude of which correlates with disease severity. Our findings also reveal a previously unknown pathogenic role of B2M in the regulation of pulmonary vascular proliferative remodeling and PH-HFpEF. These data suggest that circulating and skeletal muscle B2M can be promising targets for the management of PH-HFpEF.


Asunto(s)
Modelos Animales de Enfermedad , Insuficiencia Cardíaca , Hipertensión Pulmonar , Proteómica , Volumen Sistólico , Microglobulina beta-2 , Adulto , Anciano , Animales , Humanos , Masculino , Ratones , Persona de Mediana Edad , Microglobulina beta-2/genética , Microglobulina beta-2/sangre , Microglobulina beta-2/metabolismo , Biomarcadores/sangre , Estudios de Casos y Controles , Movimiento Celular , Proliferación Celular , Células Cultivadas , Células Endoteliales/metabolismo , Células Endoteliales/patología , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/metabolismo , Insuficiencia Cardíaca/sangre , Insuficiencia Cardíaca/genética , Hipertensión Pulmonar/fisiopatología , Hipertensión Pulmonar/metabolismo , Hipertensión Pulmonar/sangre , Hipertensión Pulmonar/etiología , Hipertensión Pulmonar/genética , Ratones Endogámicos C57BL , Ratones Noqueados , Músculo Esquelético/metabolismo , Proteómica/métodos , Arteria Pulmonar/fisiopatología , Arteria Pulmonar/metabolismo , Sirtuina 3/genética , Sirtuina 3/metabolismo , Remodelación Vascular , Función Ventricular Izquierda
19.
Nature ; 572(7771): 624-627, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31462797

RESUMEN

The discovery of unconventional superconductivity in (La,Ba)2CuO4 (ref. 1) has motivated the study of compounds with similar crystal and electronic structure, with the aim of finding additional superconductors and understanding the origins of copper oxide superconductivity. Isostructural examples include bulk superconducting Sr2RuO4 (ref. 2) and surface-electron-doped Sr2IrO4, which exhibits spectroscopic signatures consistent with a superconducting gap3,4, although a zero-resistance state has not yet been observed. This approach has also led to the theoretical investigation of nickelates5,6, as well as thin-film heterostructures designed to host superconductivity. One such structure is the LaAlO3/LaNiO3 superlattice7-9, which has been recently proposed for the creation of an artificially layered nickelate heterostructure with a singly occupied [Formula: see text] band. The absence of superconductivity observed in previous related experiments has been attributed, at least in part, to incomplete polarization of the eg orbitals10. Here we report the observation of superconductivity in an infinite-layer nickelate that is isostructural to infinite-layer copper oxides11-13. Using soft-chemistry topotactic reduction14-20, NdNiO2 and Nd0.8Sr0.2NiO2 single-crystal thin films are synthesized by reducing the perovskite precursor phase. Whereas NdNiO2 exhibits a resistive upturn at low temperature, measurements of the resistivity, critical current density and magnetic-field response of Nd0.8Sr0.2NiO2 indicate a superconducting transition temperature of about 9 to 15 kelvin. Because this compound is a member of a series of reduced layered nickelate crystal structures21-23, these results suggest the possibility of a family of nickelate superconductors analogous to copper oxides24 and pnictides25.

20.
Cereb Cortex ; 34(3)2024 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-38517175

RESUMEN

Intermittent theta-burst stimulation (iTBS) is emerging as a noninvasive therapeutic strategy for Alzheimer's disease (AD). Recent advances highlighted a new accelerated iTBS (aiTBS) protocol, consisting of multiple sessions per day and higher overall pulse doses, in brain modulation. To examine the possibility of applying the aiTBS in treating AD patients, we enrolled 45 patients in AD at early clinical stages, and they were randomly assigned to either receive real or sham aiTBS. Neuropsychological scores were evaluated before and after treatment. Moreover, we detected cortical excitability and oscillatory activity changes in AD, by the single-pulse TMS in combination with EEG (TMS-EEG). Real stimulation showed markedly better performances in the group average of Auditory Verbal Learning Test scores compared to baseline. TMS-EEG revealed that aiTBS has reinforced this memory-related cortical mechanism by increasing cortical excitability and beta oscillatory activity underlying TMS target. We also found an enhancement of local natural frequency after aiTBS treatment. The novel findings implicated that high-dose aiTBS targeting left DLPFC is rapid-acting, safe, and tolerable in AD patients. Furthermore, TMS-related increase of specific neural oscillation elucidates the mechanisms of the AD cognitive impairment ameliorated by aiTBS.


Asunto(s)
Enfermedad de Alzheimer , Estimulación Magnética Transcraneal , Humanos , Estimulación Magnética Transcraneal/métodos , Enfermedad de Alzheimer/terapia , Corteza Prefrontal/fisiología , Encéfalo , Corteza Prefontal Dorsolateral
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