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Alterations in extracellular matrix (ECM) architecture and stiffness represent hallmarks of cancer. Whether the biomechanical property of ECM impacts the functionality of tumor-reactive CD8+ T cells remains largely unknown. Here, we reveal that the transcription factor (TF) Osr2 integrates biomechanical signaling and facilitates the terminal exhaustion of tumor-reactive CD8+ T cells. Osr2 expression is selectively induced in the terminally exhausted tumor-specific CD8+ T cell subset by coupled T cell receptor (TCR) signaling and biomechanical stress mediated by the Piezo1/calcium/CREB axis. Consistently, depletion of Osr2 alleviates the exhaustion of tumor-specific CD8+ T cells or CAR-T cells, whereas forced Osr2 expression aggravates their exhaustion in solid tumor models. Mechanistically, Osr2 recruits HDAC3 to rewire the epigenetic program for suppressing cytotoxic gene expression and promoting CD8+ T cell exhaustion. Thus, our results unravel Osr2 functions as a biomechanical checkpoint to exacerbate CD8+ T cell exhaustion and could be targeted to potentiate cancer immunotherapy.
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Linfocitos T CD8-positivos , Factores de Transcripción , Animales , Femenino , Humanos , Ratones , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Línea Celular Tumoral , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Matriz Extracelular/metabolismo , Histona Desacetilasas/metabolismo , Ratones Endogámicos C57BL , Neoplasias/inmunología , Neoplasias/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal , Agotamiento de Células T , Factores de Transcripción/metabolismo , Microambiente Tumoral , Estrés MecánicoRESUMEN
Glucose consumption is generally increased in tumor cells to support tumor growth. Interestingly, we report that glycogen accumulation is a key initiating oncogenic event during liver malignant transformation. We found that glucose-6-phosphatase (G6PC) catalyzing the last step of glycogenolysis is frequently downregulated to augment glucose storage in pre-malignant cells. Accumulated glycogen undergoes liquid-liquid phase separation, which results in the assembly of the Laforin-Mst1/2 complex and consequently sequesters Hippo kinases Mst1/2 in glycogen liquid droplets to relieve their inhibition on Yap. Moreover, G6PC or another glycogenolysis enzyme-liver glycogen phosphorylase (PYGL) deficiency in both human and mice results in glycogen storage disease along with liver enlargement and tumorigenesis in a Yap-dependent manner. Consistently, elimination of glycogen accumulation abrogates liver growth and cancer incidence, whereas increasing glycogen storage accelerates tumorigenesis. Thus, we concluded that cancer-initiating cells adapt a glycogen storing mode, which blocks Hippo signaling through glycogen phase separation to augment tumor incidence.
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Carcinogénesis/metabolismo , Carcinogénesis/patología , Glucógeno/metabolismo , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Adulto , Anciano , Anciano de 80 o más Años , Animales , Línea Celular , Modelos Animales de Enfermedad , Regulación hacia Abajo/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Glucosa-6-Fosfatasa/metabolismo , Glucógeno Fosforilasa/metabolismo , Factor de Crecimiento de Hepatocito/metabolismo , Vía de Señalización Hippo , Humanos , Hígado/metabolismo , Hígado/patología , Neoplasias Hepáticas/genética , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Persona de Mediana Edad , Estadificación de Neoplasias , Transición de Fase , Lesiones Precancerosas/metabolismo , Lesiones Precancerosas/patología , Proteínas Tirosina Fosfatasas no Receptoras/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Serina-Treonina Quinasa 3/metabolismo , Proteínas Señalizadoras YAP/metabolismoRESUMEN
Antibody blockade of the inhibitory CTLA-4 pathway has led to clinical benefit in a subset of patients with metastatic melanoma. Anti-CTLA-4 enhances T cell responses, including production of IFN-γ, which is a critical cytokine for host immune responses. However, the role of IFN-γ signaling in tumor cells in the setting of anti-CTLA-4 therapy remains unknown. Here, we demonstrate that patients identified as non-responders to anti-CTLA-4 (ipilimumab) have tumors with genomic defects in IFN-γ pathway genes. Furthermore, mice bearing melanoma tumors with knockdown of IFN-γ receptor 1 (IFNGR1) have impaired tumor rejection upon anti-CTLA-4 therapy. These data highlight that loss of the IFN-γ signaling pathway is associated with primary resistance to anti-CTLA-4 therapy. Our findings demonstrate the importance of tumor genomic data, especially IFN-γ related genes, as prognostic information for patients selected to receive treatment with immune checkpoint therapy.
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Anticuerpos Monoclonales/uso terapéutico , Antígeno CTLA-4/antagonistas & inhibidores , Resistencia a Antineoplásicos/genética , Interferón gamma/genética , Melanoma/tratamiento farmacológico , Receptores de Interferón/genética , Neoplasias Cutáneas/tratamiento farmacológico , Animales , Línea Celular Tumoral , Citocinas/inmunología , Técnicas de Silenciamiento del Gen , Humanos , Ipilimumab , Melanoma/genética , Melanoma Experimental/tratamiento farmacológico , Melanoma Experimental/genética , Ratones , Ratones Endogámicos C57BL , Neoplasias Cutáneas/genética , Linfocitos T/inmunología , Receptor de Interferón gammaRESUMEN
In the version of this article initially published, the institution name for affiliation 3 (Maryland Anderson Cancer Center) was incorrect. The correct institution is MD Anderson Cancer Center. The error has been corrected in the HTML and PDF versions of the article.
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An imbalance in the lineages of immunosuppressive regulatory T cells (Treg cells) and the inflammatory TH17 subset of helper T cells leads to the development of autoimmune and/or inflammatory disease. Here we found that TAZ, a coactivator of TEAD transcription factors of Hippo signaling, was expressed under TH17 cell-inducing conditions and was required for TH17 differentiation and TH17 cell-mediated inflammatory diseases. TAZ was a critical co-activator of the TH17-defining transcription factor RORγt. In addition, TAZ attenuated Treg cell development by decreasing acetylation of the Treg cell master regulator Foxp3 mediated by the histone acetyltransferase Tip60, which targeted Foxp3 for proteasomal degradation. In contrast, under Treg cell-skewing conditions, TEAD1 expression and sequestration of TAZ from the transcription factors RORγt and Foxp3 promoted Treg cell differentiation. Furthermore, deficiency in TAZ or overexpression of TEAD1 induced Treg cell differentiation, whereas expression of a transgene encoding TAZ or activation of TAZ directed TH17 cell differentiation. Our results demonstrate a pivotal role for TAZ in regulating the differentiation of Treg cells and TH17 cells.
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Proteínas Adaptadoras Transductoras de Señales/inmunología , Diferenciación Celular/inmunología , Colitis/inmunología , Citocinas/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Péptidos y Proteínas de Señalización Intracelular/inmunología , Linfocitos T Reguladores/inmunología , Células Th17/inmunología , Acetilación , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Artritis Reumatoide/inmunología , Estudios de Casos y Controles , Inmunoprecipitación de Cromatina , Proteínas de Unión al ADN/inmunología , Proteínas de Unión al ADN/metabolismo , Citometría de Flujo , Factores de Transcripción Forkhead/inmunología , Factores de Transcripción Forkhead/metabolismo , Células HEK293 , Células HeLa , Histona Acetiltransferasas/metabolismo , Humanos , Immunoblotting , Lisina Acetiltransferasa 5 , Ratones , Ratones Noqueados , Ratones Transgénicos , Microscopía Confocal , Microscopía Fluorescente , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/inmunología , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Factor de Transcripción STAT3/inmunología , Factor de Transcripción STAT3/metabolismo , Síndrome de Sjögren/inmunología , Proteínas Smad/inmunología , Proteínas Smad/metabolismo , Factores de Transcripción de Dominio TEA , Transactivadores/metabolismo , Factores de Transcripción/inmunología , Factores de Transcripción/metabolismo , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZRESUMEN
This corrects the article DOI: 10.1038/ni.3748.
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Conventional thermochemical syntheses by continuous heating under near-equilibrium conditions face critical challenges in improving the synthesis rate, selectivity, catalyst stability and energy efficiency, owing to the lack of temporal control over the reaction temperature and time, and thus the reaction pathways1-3. As an alternative, we present a non-equilibrium, continuous synthesis technique that uses pulsed heating and quenching (for example, 0.02 s on, 1.08 s off) using a programmable electric current to rapidly switch the reaction between high (for example, up to 2,400 K) and low temperatures. The rapid quenching ensures high selectivity and good catalyst stability, as well as lowers the average temperature to reduce the energy cost. Using CH4 pyrolysis as a model reaction, our programmable heating and quenching technique leads to high selectivity to value-added C2 products (>75% versus <35% by the conventional non-catalytic method and versus <60% by most conventional methods using optimized catalysts). Our technique can be extended to a range of thermochemical reactions, such as NH3 synthesis, for which we achieve a stable and high synthesis rate of about 6,000 µmol gFe-1 h-1 at ambient pressure for >100 h using a non-optimized catalyst. This study establishes a new model towards highly efficient non-equilibrium thermochemical synthesis.
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Mitochondria need to be juxtaposed to phagosomes for the synergistic production of ample reactive oxygen species (ROS) in phagocytes to kill pathogens. However, how phagosomes transmit signals to recruit mitochondria has remained unclear. Here we found that the kinases Mst1 and Mst2 functioned to control ROS production by regulating mitochondrial trafficking and mitochondrion-phagosome juxtaposition. Mst1 and Mst2 activated the GTPase Rac to promote Toll-like receptor (TLR)-triggered assembly of the TRAF6-ECSIT complex that is required for the recruitment of mitochondria to phagosomes. Inactive forms of Rac, including the human Rac2(D57N) mutant, disrupted the TRAF6-ECSIT complex by sequestering TRAF6 and substantially diminished ROS production and enhanced susceptibility to bacterial infection. Our findings demonstrate that the TLR-Mst1-Mst2-Rac signaling axis is critical for effective phagosome-mitochondrion function and bactericidal activity.
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Fagocitos/inmunología , Fagocitos/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Infecciones Bacterianas/etiología , Infecciones Bacterianas/inmunología , Infecciones Bacterianas/metabolismo , Actividad Bactericida de la Sangre/inmunología , Línea Celular , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Antígenos de Histocompatibilidad Menor , Mitocondrias/inmunología , Mitocondrias/metabolismo , Mitocondrias/microbiología , Fagocitos/microbiología , Fagosomas/inmunología , Fagosomas/metabolismo , Fagosomas/microbiología , Proteína Quinasa C-alfa/metabolismo , Proteínas Serina-Treonina Quinasas/deficiencia , Proteínas Serina-Treonina Quinasas/genética , Sepsis/etiología , Sepsis/inmunología , Sepsis/metabolismo , Serina-Treonina Quinasa 3 , Transducción de Señal , Factor 6 Asociado a Receptor de TNF , Receptores Toll-Like/metabolismo , Ubiquitinación , Proteínas de Unión al GTP rac/genética , Proteínas de Unión al GTP rac/metabolismo , Inhibidor beta de Disociación del Nucleótido Guanina rho/metabolismoRESUMEN
Treatment with immune checkpoint blockade (ICB) has revolutionized cancer therapy. Until now, predictive biomarkers1-10 and strategies to augment clinical response have largely focused on the T cell compartment. However, other immune subsets may also contribute to anti-tumour immunity11-15, although these have been less well-studied in ICB treatment16. A previously conducted neoadjuvant ICB trial in patients with melanoma showed via targeted expression profiling17 that B cell signatures were enriched in the tumours of patients who respond to treatment versus non-responding patients. To build on this, here we performed bulk RNA sequencing and found that B cell markers were the most differentially expressed genes in the tumours of responders versus non-responders. Our findings were corroborated using a computational method (MCP-counter18) to estimate the immune and stromal composition in this and two other ICB-treated cohorts (patients with melanoma and renal cell carcinoma). Histological evaluation highlighted the localization of B cells within tertiary lymphoid structures. We assessed the potential functional contributions of B cells via bulk and single-cell RNA sequencing, which demonstrate clonal expansion and unique functional states of B cells in responders. Mass cytometry showed that switched memory B cells were enriched in the tumours of responders. Together, these data provide insights into the potential role of B cells and tertiary lymphoid structures in the response to ICB treatment, with implications for the development of biomarkers and therapeutic targets.
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Linfocitos B/inmunología , Carcinoma de Células Renales/tratamiento farmacológico , Carcinoma de Células Renales/inmunología , Inmunoterapia , Melanoma/tratamiento farmacológico , Melanoma/inmunología , Estructuras Linfoides Terciarias/inmunología , Linfocitos B/citología , Linfocitos B/metabolismo , Biomarcadores de Tumor/análisis , Carcinoma de Células Renales/patología , Carcinoma de Células Renales/cirugía , Puntos de Control del Ciclo Celular/efectos de los fármacos , Puntos de Control del Ciclo Celular/inmunología , Células Clonales/citología , Células Clonales/inmunología , Células Clonales/metabolismo , Células Dendríticas Foliculares/citología , Células Dendríticas Foliculares/inmunología , Regulación Neoplásica de la Expresión Génica , Humanos , Memoria Inmunológica/inmunología , Espectrometría de Masas , Melanoma/patología , Melanoma/cirugía , Metástasis de la Neoplasia/genética , Fenotipo , Pronóstico , RNA-Seq , Receptores Inmunológicos/inmunología , Análisis de la Célula Individual , Linfocitos T/citología , Linfocitos T/inmunología , TranscriptomaRESUMEN
Ruthenium (Ru) is an ideal substitute to commercial Pt/C for the acidic hydrogen evolution reaction (HER), but it still suffers from undesirable activity due to the strong adsorption free energy of H* (ΔGH*). Herein, we propose crystalline phase engineering by loading Ru clusters on precisely prepared cubic and hexagonal molybdenum carbide (α-MoC/ß-Mo2C) supports to modulate the interfacial interactions and achieve high HER activity. Advanced spectroscopies demonstrate that Ru on ß-Mo2C shows a lower valence state and withdraws more electrons from the support than that of Ru on α-MoC, indicative of a strong interfacial interaction. Density functional theory reveals that the ΔGH* of Ru/ß-Mo2C approaches 0 eV, illuminating an enhancement mechanism at the Ru/ß-Mo2C interface. The resultant Ru/ß-Mo2C exhibits an encouraging performance in a proton exchange membrane water electrolyzer with a low cell voltage (1.58 V@ 1.0 A cm-2) and long stability (500 h@ 1.0 A cm-2).
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Single-molecule localization microscopy (SMLM) is a powerful technique to achieve super-resolution imaging beyond the diffraction limit. Although various types of blinking fluorophores are currently considered for SMLM, intrinsic blinking fluorophores remain rare at the single-molecule level. Here, we report the synthesis of nanographene-based intrinsic burst-blinking fluorophores for highly versatile SMLM. We image amyloid fibrils in air and in various pH solutions without any additive and lysosome dynamics in live mammalian cells under physiological conditions. In addition, the single-molecule labeling of nascent proteins in primary sensory neurons was achieved with azide-functionalized nanographenes via click chemistry. SMLM imaging reveals higher local translation at axonal branching with unprecedented detail, while the size of translation foci remained similar throughout the entire network. These various results demonstrate the potential of nanographene-based fluorophores to drastically expand the applicability of super-resolution imaging.
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Parpadeo , Colorantes Fluorescentes , Animales , Microscopía Fluorescente/métodos , Colorantes Fluorescentes/química , Imagen Individual de Molécula/métodos , Lisosomas/metabolismo , Mamíferos/metabolismoRESUMEN
Dental caries is one of the most common diseases affecting more than 2 billion people's health worldwide. In a clinical setting, it is challenging to predict and proactively guard against dental cavities prior to receiving a confirmed diagnosis. Streptococcus mutans (S. mutans) in saliva has been recognized as the main causative bacterial agent that causes dental caries. High sensitivity, good selectivity, and a wide detection range are incredibly important factors to affect S. mutans detection in practical applications. In this study, we present a portable saliva biosensor designed for the early detection of S. mutans with the potential to predict the occurrence of dental cavities. The biosensor was fabricated using a S. mutans-specific DNA aptamer and S. mutans-imprinted polymers. Methylene blue was utilized as a redox probe in the sensor to generate current signals for analysis. When S. mutans enters complementarily S. mutans cavities, it blocks electron transfer between methylene blue and the electrode, resulting in decreases in the reduction current signal. The signal variations are associated with S. mutans concentrations that are useful for quantitative analysis. The linear detection range of S. mutans is 102-109 cfu mL-1, which covers the critical concentration of high caries risk. The biosensor exhibited excellent selectivity toward S. mutans in the presence of other common oral bacteria. The biosensor's wide detection range, excellent selectivity, and low limit of detection (2.6 cfu mL-1) are attributed to the synergistic effect of aptamer and S. mutans-imprinted polymers. The sensor demonstrates the potential to prevent dental caries.
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Aptámeros de Nucleótidos , Técnicas Biosensibles , Caries Dental , Saliva , Streptococcus mutans , Saliva/microbiología , Saliva/química , Streptococcus mutans/aislamiento & purificación , Técnicas Biosensibles/instrumentación , Caries Dental/diagnóstico , Caries Dental/microbiología , Aptámeros de Nucleótidos/química , Humanos , Azul de Metileno/química , Técnicas Electroquímicas/instrumentaciónRESUMEN
AIMS: SERCA2, one of the P-type pumps encoded by gene ATP2A2, is the only calcium reflux channel of the endoplasmic reticulum (ER) and participates in maintaining calcium homeostasis. The present study was designed to explore SERCA2 expression pattern in auditory hair cells and the possible mechanism underlying the effects of SERCA2 on cisplatin-induced ototoxicity. MAIN METHODS: The SERCA2 expression pattern in cochlea hair cells and HEI-OC1 cells was measured by Western blot (WB) and immunofluorescence staining. The apoptosis and its related factors were detected by TUNEL assay and WB. The expression levels of ER stress-related factors, ATF6, PERK, IRE1α, and GRP78, were measured via WB. As for the determination of SERCA2 overexpression and knockdown, plasmids and lentiviral vectors were constructed, respectively. KEY FINDINGS: We found that SERCA2 was highly expressed in cochlea hair cells and HEI-OC1 cells. Of note, the level of SERCA2 expression in neonatal mice was remarkably higher than that in adult mice. Under the exposure of 30 µM cisplatin, SERCA2 was down-regulated significantly compared with the control group. In addition, cisplatin administration triggered the occurrence of ER stress and apoptosis. Those events were reversed by overexpressing SERCA2. On the contrary, SERCA2 knockdown could aggravate the above processes. SIGNIFICANCE: The findings from the present study disclose, for the first time, that SERCA2 is abundantly expressed in cochlea hair cells, and the suppression of SERCA2 caused by cisplatin could trigger ER homeostasis disruption, thereby implying that SERCA2 might be a promising target to prevent cisplatin-induced cytotoxicity of hair cells.
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Apoptosis , Cisplatino , Chaperón BiP del Retículo Endoplásmico , Estrés del Retículo Endoplásmico , Células Ciliadas Auditivas , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico , Cisplatino/toxicidad , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico/metabolismo , Animales , Estrés del Retículo Endoplásmico/efectos de los fármacos , Ratones , Apoptosis/efectos de los fármacos , Células Ciliadas Auditivas/efectos de los fármacos , Células Ciliadas Auditivas/metabolismo , Células Ciliadas Auditivas/patología , Línea Celular , Antineoplásicos/toxicidad , Masculino , Ototoxicidad/prevención & controlRESUMEN
Refractory/relapsed idiopathic multicentric Castleman disease (R/R iMCD) has limited treatment options. With studies showing increased mTOR activation in iMCD patients, sirolimus becomes an attractive and promising therapy for R/R iMCD. Here we report the results of a retrospective study involving 26 R/R iMCD patients treated with sirolimus-containing regimen. The median age at sirolimus initiation was 40.5 years (23-60), with a median prior treatment line of 2 (1-5). 18 patients (69.2%) achieved symptomatic and biochemical response, with a median time to at least overall partial remission of 1.9 months (0.5-14.6). The median follow-up time from sirolimus initiation was 11.7 months (1.6-50.7) and the median time to next treatment (TTNT) was 46.2 months. No patients died at the end of follow-up. Most of the patients in the cohort are in ongoing responses and continue sirolimus therapy. Sirolimus is well tolerated with minor adverse effects. In conclusion, sirolimus is effective for R/R iMCD patients with good tolerance.
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Enfermedad de Castleman , Sirolimus , Humanos , Enfermedad de Castleman/tratamiento farmacológico , Sirolimus/uso terapéutico , Sirolimus/administración & dosificación , Estudios Retrospectivos , Adulto , Masculino , Femenino , Persona de Mediana Edad , Adulto Joven , Recurrencia , Resultado del Tratamiento , Estudios de Seguimiento , Inmunosupresores/uso terapéutico , Inducción de RemisiónRESUMEN
Removal of hetero ions from the hydrogen peroxide solution is a crucial step in purifying electronic-grade H2O2. Conventional adsorption materials are challenged to meet the need for the simultaneous adsorption of both anions and cations in solvents. UiO-66 (Zr) modified by acetic acid and amino group for simultaneous adsorption of phosphate and Pb2+ in H2O2 purification was fabricated in this work. The as-prepared defective UiO-66-NH2 (Zr) demonstrated a significant increase in specific surface area and porosity, along with more exposed sites for phosphate and Pb2+ adsorption. The adsorption capacity of De-UiO-66-NH2 for phosphate and Pb2+ in H2O2 solution was 52.28 mg g-1 and 35.4 mg g-1, which is 1.19 times and 1.88 times that of unmodified UiO-66 (Zr), respectively. The trace simultaneous adsorption with both 100 ppb phosphate and Pb2+ showed removal rates of 94.0% and 88.7%, respectively, confirming the practicality of MOF materials in the purification of electronic chemicals. This work highlights the potential of Zr-based MOFs as anionic and cationic simultaneous adsorbents for highly efficient purification of electronic-grade solvents.
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Traumatic brain injury (TBI) leads to disturbed brain discharge rhythm, elevated excitability, anxiety-like behaviors, and decreased learning and memory capabilities. Cognitive dysfunctions severely affect the quality of life and prognosis of TBI patients, requiring effective rehabilitation treatment. Evidence indicates that moderate exercise after brain injury decreases TBI-induced cognitive decline. However, the underlying mechanism remains unelucidated. Our results demonstrate that TBI causes cognitive impairment behavior abnormalities and overexpression of Nav1.1, Nav1.3 and Nav1.6 proteins inside the hippocampus of mice models. Three weeks of voluntary running wheel (RW) exercise treatments before or/and post-injury effectively redressed the aberrant changes caused by TBI. Additionally, a 10% exercise-conditioned medium helped recover cell viability, neuronal sodium current and expressions of Nav1.1, Nav1.3 and Nav1.6 proteins across cultured neurons after injury. Therefore, the results validate the neuroprotection induced by voluntary RW exercise treatment before or/and post-TBI. The RW exercise-induced improvement in cognitive behaviors and neuronal excitability could be associated with correcting the Nav1.1, Nav1.3, and Nav1.6 expression levels. The current study proves that voluntary exercise is an effective treatment strategy against TBI. The study also highlights novel potential targets for rehabilitating TBI, including the Navs proteins.
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Lesiones Traumáticas del Encéfalo , Lesiones Encefálicas , Canales de Sodio Activados por Voltaje , Humanos , Ratones , Animales , Calidad de Vida , Lesiones Traumáticas del Encéfalo/complicaciones , Lesiones Traumáticas del Encéfalo/terapia , CogniciónRESUMEN
The tunable structure and other properties of organic materials suggest that they can potentially solve the shortcomings of traditional anodes such as graphite. We successfully introduced an organoboron unit into the thiophene-based polymer PBT-2 to construct a donor-acceptor polymer anode. The charge delocalization and LUMO energy level resulting from the unique structure of this material enabled good redox activity and a very stable electrochemical performance in electrochemical tests, with a reversible capacity of 262 mA h g-1 at 0.5 A g-1 and >10 000 cycles at 1 A g-1 with a decay of 0.056 per cycle. Accordingly, targeted structural design to overcome the shortcomings of active units such as thiophene can effectively regulate their electrochemical performance, providing a solution for the development of high-performance anode materials for use in lithium ion batteries.
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Significant discrepancies were observed between the experiments and the simulations for NH2 time-histories in monomethylhydrazine pyrolysis with the robust mechanism proposed by Pascal and Catoire. The rate of formation analyses for NH2 indicated the significance of the reaction NH2NH + NH2 = H2NN + NH3, which has not been well-defined. In this study, ab initio calculations were performed for the theoretical description of the NH2NH + NH2 chemistry. Most stationary points on the potential energy surface were quantified at the CCSD(T)/CBS//M06-2X/aug-cc-pVTZ level, and the multireference methods were employed for barrier-less reaction and some transition states. The temperature- and pressure-dependent rate coefficients were determined using classical and microcanonical variational transition state theories. Four primary reaction channels were identified as competitive: 1) The H atom abstraction reaction yielding N2H2(T) + NH3, dominating at 1350-3000 K across the 0.001-100 atm pressure range. 2) The H atom abstraction reaction forming N2H2(S) + NH3, dominating at 800-1350 K and competing with the processes of chemical activation and collisional stabilization below 800 K. 3) The chemical-activated reaction resulting in H2NN(S) + NH3, dominating below 800 K at 0.001 atm. 4) The collisional-stabilized recombination reaction leading to N3H5, becoming significant as pressure increases and dominating below 600 and 650 K at 1 and 100 atm, respectively. The implications of newly calculated NH2NH + NH2 kinetics for the monomethylhydrazine pyrolysis mechanism were evaluated, and updates were implemented. Sensitivity analyses indicated the necessity of additional research efforts to comprehend the dynamics of CH3NH2 unimolecular and N2H2 + NH2 reaction systems. The rate coefficients presented in this study can be employed to develop the chemical kinetic model of nitryl-containing systems.
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The thermo-kinetic aspects of 3-hydroxybutyric acid (3-HBA) pyrolysis in the gas phase were investigated using density functional theory (DFT), specifically the M06-2X theoretical level in conjunction with the cc-pVTZ basis set. The obtained data were compared with benchmark CBS-QB3 results. The degradation mechanism was divided into 16 pathways, comprising 6 complex fissions and 10 barrierless reactions. Energy profiles were calculated and supplemented with computations of rate coefficients and branching ratios over the temperature range of 600-1700 K at a pressure of 1 bar using transition state theory (TST) and Rice-Ramsperger-Kassel-Marcus (RRKM) methods. Thermodynamics results indicated the presence of six stable conformers within a 4 kcal mol-1 energy range. The estimated chemical kinetics results suggested that TST and RRKM approaches are comparable, providing confidence in our calculations. The branching ratio analysis reveals that the dehydration reaction pathway leading to the formation of H2O and CH3CHâCHCO2H dominates entirely at T ≤ 650 K. At these temperatures, there is a minor contribution from the simple homolytic bond fission reaction, yielding related radicals [CH3â¢CHOH + â¢CH2CO2H]. However, at T ≥ 700 K, this reaction becomes the primary decomposition route. At T = 1700 K, there is a minor involvement of a reaction pathway resulting in the formation of CH3CH(OH)â¢CH2 + â¢CHO(OH) with an approximate contribution of 16%, and a reaction leading to [â¢CH3 + â¢CH2OHCH2CO2H] with around 9%.