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Cadmium (Cd) contamination of farmland soils leads to Cd accumulation in crops and reduced micronutrient uptake, posing grave risks to food safety. Herein, we investigated the enrichment and transportation patterns of Cd and trace elements in different parts of six wheat genotypes grown in weakly alkaline Cd-contaminated soils via pot experiments. The results revealed that the wheat grain variety with high Cd accumulation (Ningmai13) demonstrated a 1.94-fold increase compared to the variety with low accumulation (Yanong0428). The transfer factor of Cd from wheat straw to grain ranged from 0.319 to 0.761, while the transfer factor of Cd from root to straw ranged from 0.167 to 0.461. Furthermore, the concentrations of other metals in wheat grains followed the order of Zn > Mn > Fe > Cu. There was a significant positive correlation between Cd and Mn in grains, indicating a potential synergistic effect. Overall, this study provides valuable insights into the regulation of micronutrient intake to modulate Cd uptake in wheat.
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Cádmio , Genótipo , Poluentes do Solo , Oligoelementos , Triticum , Triticum/metabolismo , Cádmio/metabolismo , Cádmio/análise , Poluentes do Solo/metabolismo , Poluentes do Solo/análise , Oligoelementos/metabolismo , Oligoelementos/análise , Solo/químicaRESUMO
Cadmium (Cd) contamination in soils threatens food security, while cultivating low-Cd-accumulative varieties, coupled with agro-nanotechnology, offers a potential solution to reduce Cd accumulation in crops. Herein, foliar application of selenium nanoparticles (SeNPs) was performed on seedlings of two low-Cd-accumulative wheat (Triticum aestivum L.) varieties grown in soil spiked with Cd at 3 mg/kg. Results showed that foliar application of SeNPs at 0.16 mg/plant (SeNPs-M) significantly decreased the Cd content in leaves of XN-979 and JM-22 by 46.4 and 40.8 %, and alleviated oxidative damage. The wheat leaves treated with SeNPs-M underwent significant metabolic and transcriptional reprogramming. On one hand, four specialized antioxidant metabolites such as L-Tyrosine, beta-N-acetylglucosamine, D-arabitol, and monolaurin in response to SeNPs in JM-22 and XN-979 is the one reason for the decrease of Cd in wheat leaves. Moreover, alleviation of stress-related kinases, hormones, and transcription factors through oxidative post-translational modification, subsequently regulates the expression of defense genes via Se-enhanced glutathione peroxidase. These findings indicate that combining low-Cd-accumulative cultivars with SeNPs spraying is an effective strategy to reduce Cd content in wheat and promote sustainable agricultural development.
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Cádmio , Selênio , Poluentes do Solo , Triticum , Triticum/metabolismo , Triticum/genética , Triticum/efeitos dos fármacos , Cádmio/toxicidade , Cádmio/metabolismo , Folhas de Planta/metabolismo , Nanopartículas/toxicidadeRESUMO
In Southern China, the co-occurrence of arsenic (As) and antimony (Sb) contamination in soils around Sb mines presents an environmental challenge. During the flooding period of mining-impacted soils, anaerobic reduction of iron (Fe) oxides enhances the mobilization and bioavailability of Sb and As, further elevating the risk of Sb and As entering the food chain. To address this problem, activated carbon (AC) and biochar (BC) were applied to remediate flooded mining-impacted soils. Our results explored that AC can significantly decrease mobilization by 9-97 % for Sb and 9-67 % for As through inhibiting Fe(III) mineral reduction and dissolution in flooded soils. In contrast, there was no significant effect of BC. This was attributed to the strong adsorption of soil dissolved organic matter (DOM) by AC compared to BC, while DOM as electron shuttle is crucial for microbial Fe(III) reduction. Consequently, the DOM sequestration by AC effectively mitigates Sb and As leaching in contaminated mining soils.
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Antimônio , Arsênio , Carvão Vegetal , Mineração , Poluentes do Solo , Antimônio/química , Arsênio/química , Poluentes do Solo/química , Carvão Vegetal/química , Adsorção , Inundações , Solo/química , Recuperação e Remediação Ambiental/métodosRESUMO
Foliar application of beneficial nanoparticles (NPs) exhibits potential in reducing cadmium (Cd) uptake in crops, necessitating a systematic understanding of their leaf-root-microorganism process for sustainable development of efficient nano-enabled agrochemicals. Herein, wheat grown in Cd-contaminated soil (5.23 mg/kg) was sprayed with different rates of four commonly used NPs, including nano selenium (SeNPs)/silica (SiO2NPs)/zinc oxide/manganese dioxide. SeNPs and SiO2NPs most effectively reduced the Cd concentration in wheat grains. Compared to the control, Cd concentration in grains was significantly decreased by 35.0 and 33.3% by applying 0.96 mg/plant SeNPs and 2.4 mg/plant SiO2NPs, and the grain yield was significantly increased by 33.9% with SeNPs application. Down-regulated gene expression of Cd transport proteins (TaNramp5 and TaLCT1) and up-regulated gene expression of vacuolar Cd fixation proteins (TaHMA3 and TaTM20) were observed with foliar SeNPs and SiO2NPs use. SeNPs increased the levels of leaf antioxidant metabolites. Additionally, foliar spray of SeNPs resulted in lower abundances of rhizosphere organic acids and reduced Cd bioavailability in rhizosphere soil, and soil microorganisms related to carbon and nitrogen (Solirubrobacter and Pedomicrobium) were promoted. Our findings underscore the potential of the foliar application of SeNPs and SiO2NPs as a plant and rhizosphere soil metabolism-regulating approach to reduce Cd accumulation in wheat grains.
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Cadmium (Cd) contamination in rice ecosystems posed a critical challenge to global food security and environmental health. This study aimed to unveil the key mechanisms trough hydroponic experiments by which chloride (Cl-) promoted the absorption and accumulation of cadmium (Cd) in rice plants. The findings elucidated that the addition of Cl- increased Cd uptake by rice roots (5.1 % â¼ 61 %), acting both directly by enhancing root morphology and indirectly through regulating of the main transporter genes of Cd. The study unveiled that Cl- addition significantly improves Cd bioavailability in roots, which was discernible through the augmentation of Cd concentration and proportion in subcellular fractions, coupled with elevated energy values in key cellular components. Moreover, Cl- addition further augmented the intricate process of Cd transport from roots to shoots (16.1- 86.7 %), which was mainly attributed to the underexpression of OsHMA3 and the decrease in the formation of sulfuhydryl substances. This research provides a comprehensive understanding of the complex mechanisms governing Cd dynamics in rice plants in the presence of Cl-. By elucidating these processes, our findings not only contribute to fundamental knowledge in plant metal uptake but also hold promising implications for mitigating Cd contamination in rice cultivation systems.
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Oryza , Poluentes do Solo , Cádmio , Oryza/fisiologia , Cloretos , Ecossistema , Transporte Biológico , Raízes de PlantasAssuntos
Antineoplásicos , Aprovação de Drogas , Humanos , Oncologia , Antineoplásicos/uso terapêutico , ChinaRESUMO
Nano-biochar (N-BC) is an emerging nanomaterial with potential applications in various fields. Understanding its behavior in the environment and its interaction with plants is crucial for assessing its ecological implications and potential risks to the food chain. In this study, we investigated the absorption and transportation of N-BC by wheat and Chinese cabbage plants using microscopy techniques and stable isotope analysis. Our results revealed that N-BC particles were readily absorbed by the plants through their root systems and transported to the aboveground tissues. Scanning electron microscopy and transmission electron microscopy provided visual evidence of N-BC particles inside the plants, predominantly located in the xylem and cell walls of the cortical tissue. Stable isotope analysis confirmed the uptake and transportation of N-BC, with elevated isotopic values observed in the plant tissues exposed to 13C-N-BC. Our results demonstrated that around 50.2 %-52.4 % of the absorbed N-BC by plants was accumulated in the roots of wheat and Chinese cabbage, and the remaining fraction was transferred to the shoots including steam (31.0 %-32.1 %) and leaf (16.5 %-17.6 %). Importantly, we observed significant accumulation of N-BC in the edible parts of Chinese cabbage, raising concerns about its potential entry into the food chain and associated health risks. These findings highlight the need for further research to explore the specific pathways and modes of N-BC uptake and transport in plants. Monitoring the presence of N-BC in the environment and its potential impact on the food chain is crucial for ensuring food security and safeguarding human health.
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Brassica , Poluentes do Solo , Humanos , Cadeia Alimentar , Raízes de Plantas/metabolismo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Carvão Vegetal/metabolismo , Brassica/metabolismo , Isótopos/análise , Poluentes do Solo/análise , SoloRESUMO
The molecular and metabolic mechanisms of foliar selenium (Se) nanoparticles (SeNPs) application in mitigating cadmium (Cd) toxicity in crops have not been well studied. Herein, hydroponically cultured maize seedlings were exposed to Cd (20 µM) and treated without and with foliar SeNPs application. Effects of SeNPs on Cd transporter genes and plant metabolism were also explored. Results showed that compared to control plants without Cd exposure, Cd exposure decreased shoot height (16.8 %), root length (17.7 %), and fresh weight of root (24.2 %), stem (28.8 %), and foliar-applied leaves (Se-leaves) (15.0 %) via oxidative damage. Compared to Cd exposure alone, foliar SeNPs application at 20 mg/L (0.25 mg/plant) significantly alleviated the Cd toxicity by promoting photosynthesis and antioxidant capacity and fixing Cd in cell wall. Meanwhile, the mineral concentration of Ca (26.0 %), Fe (55.4 %), Mg (27.0 %), Na (28.6 %), and Zn (10.1 %) in Se-leaves was improved via foliar SeNPs application at 20 mg/L. QRT-PCR analysis further revealed that down- and up-regulation of the expression of ZmHMA2 and ZmHMA3 gene in Se-leaves contributed to reduced translocation of Cd in plants and enhanced Cd sequestration in the vacuole, respectively. Metabolomic results further indicated that metabolic pathways including carbohydrate metabolism, membrane transport, translation, amino acid metabolism, and energy metabolism were significantly affected by foliar SeNPs application. In conclusion, foliar SeNPs application at 20 mg/L could be a prospective strategy to mitigate Cd toxicity in maize.
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Nanopartículas , Selênio , Poluentes do Solo , Antioxidantes/metabolismo , Selênio/metabolismo , Cádmio/análise , Plântula , Zea mays/metabolismo , Metabolômica , Expressão Gênica , Poluentes do Solo/análiseRESUMO
Recently, hydroxyl radical (â¢OH) production during soil redox fluctuations has been increasingly reported, but the low efficiency of contaminant degradation is the barrier for engineering remediation. The widely distributed low-molecular-weight organic acids (LMWOAs) might greatly enhance â¢OH production due to their strong interactions with Fe(II) species, but it was less investigated. Herein, we found that LMWOAs amendment (i.e., oxalic acid (OA) and citric acid (CA)) significantly enhanced â¢OH production by 1.2 -19.5 times during oxygenation of anoxic paddy slurries. Compared with OA and acetic acid (AA) (78.4 -110.3 µM), 0.5 mM CA showed the highest â¢OH accumulation (140.2 µM) due to the elevated electron utilization efficiency derived from its strongest capacity for complexation. Besides, increasing CA concentrations (within 6.25 mM) dramatically enhanced the â¢OH production and imidacloprid (IMI) degradation (increased by 48.6%), and further decreased due to the extensive competition from excess CA. Compared to 0.5 mM CA, the synergistic effects of acidification and complexation induced by 6.25 mM CA rendered more formation of exchangeable Fe(II) that easily coordinated with CA, and thus significantly enhanced its oxygenation. This study proposed promising strategies for regulating natural attenuation of contaminants using LMWOAs in agricultural fields, especially soils with frequent occurrence of redox fluctuations.
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The TCR integrates forces in its triggering process upon interaction with pMHC. Force elicits TCR catch-slip bonds with strong pMHCs but slip-only bonds with weak pMHCs. We develop two models and apply them to analyze 55 datasets, demonstrating the models' ability to quantitatively integrate and classify a broad range of bond behaviors and biological activities. Comparing to a generic two-state model, our models can distinguish class I from class II MHCs and correlate their structural parameters with the TCR/pMHC's potency to trigger T cell activation. The models are tested by mutagenesis using an MHC and a TCR mutated to alter conformation changes. The extensive comparisons between theory and experiment provide model validation and testable hypothesis regarding specific conformational changes that control bond profiles, thereby suggesting structural mechanisms for the inner workings of the TCR mechanosensing machinery and plausible explanations of why and how force may amplify TCR signaling and antigen discrimination.
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Receptores de Antígenos de Linfócitos T , Transdução de Sinais , Receptores de Antígenos de Linfócitos T/metabolismo , Ativação Linfocitária , Genes MHC da Classe II , Mutagênese , Ligação ProteicaRESUMO
Background: With the growing notion of patient-focused drug development, the quality of life and other patient-reported outcomes (PROs) of cancer patients are gaining considerable attention. Several drug regulatory agencies, including the U.S. Food and Drug Administration (FDA), are calling attention to PROs. This review aims to comprehensively characterise the application of PROs and regulatory considerations for PROs in the FDA-approved novel oncology drugs. Methods: The FDA review documents and labels for novel oncology drugs approved from July 2017 to July 2022 were retrieved. We collected and analysed drug approval information, types of endpoints for PROs, PRO measures, designs of trials including PROs, and regulatory comments on PRO-related contents. Findings: Results demonstrated that PROs were used more commonly for solid tumours than hematologic malignancies, which might be correlated with the disease characteristics. We further categorised and analysed existing PRO measures, providing insight for tool selection in future oncology trial design. Our findings also indicated that PROs currently do not play a significant role in oncology drug approvals. The major deficiencies related to PROs commented on by FDA reviewers were analysed, followed by recommendations for improvements. Interpretation: This review demonstrates that PROs currently do not play a significant role in oncology drug marketing review, and how they can be used to support the approval of new oncology drugs is still in the exploratory stage. This current situation is not only related to the deficiencies in the design and implementation of PRO-related contents in oncology trials, but more importantly, it is a reminder that we should pay more attention to patient experience in the development of oncology drugs. Funding: This study was not supported by any funding.
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The interface between the absorber and transport layers is shown to be critical for highly efficient perovskite solar cells (PSCs). The undesirable physical and chemical properties of interfacial layers often cause unfavorable band alignment and interfacial states that lead to high charge-carrier recombination and eventually result in lower device performance. Herein, we demonstrate a simple and effective strategy to improve the performance of PSCs by constructing a conduction band offset (CBO) with a small spike, through the inductive effect induced by an organic small molecule. As a result, the modified devices show an enhancement in all photovoltaic performance characteristics with a power conversion efficiency (PCE) increase of 10.6% and retaining more than 94% of its initial PCE after 1800 h of exposure to N2. Importantly, we find that a moderate spike-like CBO at the interface between the perovskite film and hole transport layer facilitates rapid charge-carrier injection in devices and reduces charge recombination at the interface, thereby increasing the open-circuit voltage and fill factor. Furthermore, a large spike barrier at the interface increases device resistance, leading to a reduced fill factor. Our present work provides valuable information for understanding the influence of a spike-like CBO on charge-carrier dynamics to further improve the performance and stability of PSCs.
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BACKGROUND: Patients receiving hematopoietic stem cell transplantation (HSCT) or chimeric antigen receptor T cell (CAR T-cell) therapy are immunocompromised and at high risk of viral infection, including SAR2-CoV-2 infection. However, the effectiveness and safety of COVID-19 vaccines in these recipients is not well characterized. The present meta-analysis evaluated the serologic response and safety of COVID-19 vaccines in these population. METHODS: Literature databases (MEDLINE, EMBASE, Web of Science, MedRvix and BioRvix) were searched for original studies with serologic response post COVID-19 vaccination in HSCT or CAR T-cell recipients published until July 14, 2022. The analysis included 27 observational studies with a total of 2899 patients receiving allogeneic HSCT (2506), autologous HSCT (286) or CAR T-cell therapy (107), and 683 healthy participants with serologic response data. Random effects models were used to pool the rate of serologic response to COVID-19 vaccination in HSCT or CAR T-cell recipients and odds ratio comparing with healthy controls. RESULTS: The pooled seropositivity rates in HSCT and CAR T-cell recipients were 0.624 [0.506-0.729] for one dose, 0.745 [0.712-0.776] for two doses. The rates were significantly lower than those in healthy controls (nearly 100%). In subgroup analysis, CAR T-cell recipients exhibited an even lower seroconversion rate (one dose: 0.204 [0.094-0.386]; two doses: 0.277 [0.190-0.386]) than HSCT counterparts (one dose: 0.779 [0.666-0.862]; two doses: 0.793 [0.762-0.821]). The rates were comparable between autologous and allogeneic HSCT recipients. Other possible impact factors related to seropositivity were time interval between therapy and vaccination, use of immunosuppressive drugs and immune cell counts. Most vaccine-related adverse effects were mild and resolvable, comparable to general population. CONCLUSIONS: This analysis revealed a diminished response to COVID-19 vaccines in HSCT or CAR T-cell recipients. Our findings may inform regular COVID-19 vaccination at appropriate intervals after HSCT or CAR T-cell therapy.
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Silver is an antimicrobial agent that is used extensively in consumer products, such as fabrics and humidifiers. Silver ion (Ag+) uptake in bacteria represents a crucial phase of antimicrobial activity. However, the uptake mechanism of Ag+ in bacteria remains largely unknown. The genus Shewanella drives many geochemical processes of nutrients and pollutants in soils. In the present study, Ag+ uptake by Shewanella oneidensis MR-1 was first investigated in a laboratory in defined anaerobic, oligotrophic, and inorganic media with or without cations (potassium ions [K+], magnesium ions [Mg2+], and zinc ions [Zn2+]). Our results revealed variations in antimicrobial activity of Ag+ in the presence of Mg2+ and Zn2+. First, Mg2+ significantly decreased antimicrobial activity of Ag+ in S. oneidensis MR-1 by inhibiting cellular Ag+ uptake when compared with K+. The results were consistent with that of Co2+ (Mg2+ channel blocker) decreased Ag+ uptake by S. oneidensis MR-1. Moreover, Mg2+ promoted riboflavin secretion and facilitated the formation of metallic Ag nanoparticles on bacterial surfaces, which was beneficial for extracellular electron transfer and consequently reduced antibacterial activity of Ag+. Second, Zn2+ increased the antimicrobial activity of Ag+ in S. oneidensis MR-1, although the effect on Ag+ uptake was minimal. A synergistic interaction between Zn2+ and Ag+ led to an increase in dead cells and decreased ferrihydrite reduction capacity. The findings suggest that Mg2+ could reduce the environmental risk of Ag+ to soil bacteria, while Zn2+ should be of particular concern due to its synergistic antimicrobial effect on bacteria.
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Anti-Infecciosos , Nanopartículas Metálicas , Shewanella , Cátions , Prata/farmacologiaRESUMO
Staphylococcus aureus is a major cause of severe pulmonary infections. The evolution of multi-drug resistant strains limits antibiotic treatment options. To date, all candidate vaccines tested have failed, highlighting the need for an increased understanding of the immunological requirements for effective S. aureus immunity. Using an S. aureus strain engineered to express a trackable CD4+ T cell epitope and a murine model of S. aureus pneumonia, we show strategies that lodge Th1 polarised bacterium specific CD4+ tissue resident memory T cells (Trm) in the lung can significantly attenuate the severity of S. aureus pneumonia. This contrasts natural infection of mice that fails to lodge CD4+ Trm cells along the respiratory tract or provide protection against re-infection, despite initially generating Th17 bacterium specific CD4+ T cell responses. Interestingly, lack of CD4+ Trm formation after natural infection in mice appears to be reflected in humans, where the frequency of S. aureus reactive CD4+ Trm cells in lung tissue is also low. Our findings reveal the protective capacity of S. aureus specific respiratory tract CD4+ Th1 polarised Trm cells and highlight the potential for targeting these cells in vaccines that aim to prevent the development of S. aureus pneumonia.
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Orthomyxoviridae , Pneumonia Bacteriana , Pneumonia Estafilocócica , Vacinas , Animais , Memória Imunológica , Pulmão , Camundongos , Staphylococcus aureus , Células Th1 , Células Th17RESUMO
Silver ions (Ag+) directly emitted from industrial sources or released from manufactured Ag nanoparticles (AgNPs) in biosolid-amended soils have raised concern about the risk to ecosystems. However, our knowledge of Ag+ toxicity, internalization, and transformation mechanisms to bacteria is still insufficient. Here, we combine the advanced technologies of hyperspectral imaging (HSI) and single-particle inductively coupled plasma mass spectrometry to visualize the potential formed AgNPs inside the bacteria and evaluate the contributions of biological and non-biological processes in the uptake and transformation of Ag+ by Shewanella oneidensis MR-1. The results showed a dose-dependent toxicity of Ag+ to S. oneidensis MR-1 in the ferrihydrite bioreduction process, which was primarily induced by the actively internalized Ag. Moreover, both HSI and cross-section high-resolution transmission electron microscopy results confirmed that Ag inside the bacteria existed in the form of particulate. The Ag mass distribution in and around live and inactivated cells demonstrated that the uptake and transformation of Ag+ by S. oneidensis MR-1 were mainly via biological process. The bioaccumulation of Ag+ may be lethal to bacteria. A better understanding of the uptake and transformation of Ag+ in bacteria is central to predict and monitor the key factors that control Ag partitioning dynamics at the biointerface, which is critical to develop practical risk assessment and mitigation strategies.
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Nanopartículas Metálicas , Shewanella , Ecossistema , Nanopartículas Metálicas/química , Prata/químicaRESUMO
BACKGROUND/OBJECTIVES: Enucleation is an effective surgical method to treat pancreatic insulinoma, however, the incidence of clinically relevant postoperative pancreatic fistula (CR-POPF) is high. We aim to investigate the risk factors for CR-POPF which have not been well characterized and develop effective methods to prevent CR-POPF after enucleation. METHODS: This retrospective cohort study included 161 patients diagnosed with insulinoma from June 2016 to July 2020 in Peking Union Medical College Hospital. The risk factors for CR-POPF were evaluated and the role of prophylactic pre-operative pancreatic stent to prevent the occurrence of CR-POPF after enucleation of pancreatic insulinoma were explored. RESULTS: A cohort of 161 insulinoma cases were reviewed. The CT or MRI imaging reports could be tracked in 108 cases. A total of 96 patients underwent surgery, while 81 experienced pancreatic enucleation. Univariate and multivariate analyses showed that the distance from insulinoma to the main pancreatic duct (MPD) ≤2 mm was an independent risk factor for CR-POPF (p = 0.003, OR = 6.011, 95% Cl 1.852-19.512). The pre-operative pancreatic stent substantially reduced the incidence of CR-POPF in patients with tumor located in proximity to (distance ≤2 mm) the MPD (CR-POPF of the stented group vs the non-stented group: 37.5% vs 71.4%, p = 0.028). CONCLUSIONS: The distance from insulinoma to MPD ≤2 mm is a predictive factor for CR-POPF after enucleation. Pancreatic duct stenting may benefit patients with insulinoma in proximity to the MPD by enabling a lower CR-POPF rate, so it should be considered before the enucleation of the insulinoma in proximity to the MPD (distance ≤2 mm).
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The nasal-associated lymphoid tissues (NALTs) are mucosal-associated lymphoid organs embedded in the submucosa of the nasal passage. NALTs represent a known site for the deposition of inhaled antigens, but little is known of the mechanisms involved in the induction of immunity within this lymphoid tissue. We find that during the steady state, conventional dendritic cells (cDCs) within the NALTs suppress T cell responses. These cDCs, which are also prevalent within human NALTs (tonsils/adenoids), express a unique transcriptional profile and inhibit T cell proliferation via contact-independent mechanisms that can be diminished by blocking the actions of reactive oxygen species and prostaglandin E2 Although the prevention of unrestrained immune activation to inhaled antigens appears to be the default function of NALT cDCs, inflammation after localized virus infection recruited monocyte-derived DCs (moDCs) to this region, which diluted out the suppressive DC pool, and permitted local T cell priming. Accommodating for inflammation-induced temporal changes in NALT DC composition and function, we developed an intranasal vaccine delivery system that coupled the recruitment of moDCs with the sustained release of antigen into the NALTs, and we were able to substantially improve T cell responses after intranasal immunization. Thus, homeostasis and immunity to inhaled antigens is tuned by inflammatory signals that regulate the balance between conventional and moDC populations within the NALTs.
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Tonsila Faríngea/imunologia , Células Dendríticas/imunologia , Ativação Linfocitária , Tonsila Palatina/imunologia , Infecções Respiratórias/imunologia , Tonsila Faríngea/citologia , Animais , Apresentação de Antígeno , Antígenos de Bactérias/imunologia , Antígenos Virais/imunologia , Modelos Animais de Doenças , Humanos , Imunidade nas Mucosas , Exposição por Inalação/efeitos adversos , Camundongos , Camundongos Knockout , Monócitos/imunologia , Mucosa Nasal/imunologia , Tonsila Palatina/citologia , Infecções Respiratórias/microbiologia , Linfócitos T/imunologiaRESUMO
Staphylococcus aureus is found in the nasal cavity of up to 30% of the human population. Persistent nasal carriage of S. aureus is a risk factor for influenza virus-induced secondary bacterial pneumonia. There is limited understanding of the factors that cause S. aureus to shift from the upper to the lower respiratory tract and convert from a commensal organism to an invasive pathogen. Here we show that neutrophils actively prevent S. aureus dissemination. Establishment of a mouse model of localized S. aureus nasal carriage revealed variations in the longevity of persistence of S. aureus isolates. Improved persistence within this site was associated with reduced nasal inflammation, less neutrophil egress into the airways and reduced neutrophil-bacteria association. Neutrophil depletion of mice with localized S. aureus nasal carriage triggered the development of an invasive S. aureus infection. Moreover, utilizing a model of influenza-induced staphylococcal pneumonia we showed that treatment with granulocyte-colony-stimulating factor, a potent enhancer of neutrophil number and function, significantly reduced bacterial loads in the lung and improved disease outcomes. These data reveal that neutrophils play an important and active role in confining S. aureus to the upper respiratory tract and highlight the use of approaches that improve neutrophil function as effective strategies to attenuate morbidity associated with staphylococcal pneumonia.
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Pulmão/microbiologia , Neutrófilos/imunologia , Pneumonia Estafilocócica/imunologia , Animais , Camundongos , Nariz/microbiologia , Infecções por Orthomyxoviridae , Staphylococcus aureusRESUMO
Tissue-resident memory T (Trm) cells are described as having a "sensing and alarming" function, meaning they can rapidly release cytokines in response to local cognate antigen recognition, which in turn, draws circulating immune cells into the tissue. Here, we show noncognate, bystander activation can also trigger the sensing and alarming function of pulmonary CD8+ Trm cells. Virus-specific CD8+ Trm cells lodged in the lung parenchyma, but not memory CD8+ T cells located in the vasculature, rapidly synthesize interferon γ (IFN-γ) following the inhalation of heat-killed bacteria or bacterial products, a process driven by interleukin-12 (IL-12)/IL-18 exposure. We show that a respiratory bacterial infection leads to bystander activation of lung Trm cells that boosts neutrophil recruitment into the airways and attenuates the severity of bacterial pneumonia. These data reveal that lung Trm cells have innate-like properties, enabling amplification of inflammation and participation in noncognate responses to bacterial infections.