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1.
J Hazard Mater ; 421: 126758, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34352527

RESUMO

Organophosphorus compounds were proposed to impair immune surveillance and increase the total burden of pathogens. However, scarce attention has been paid to the effects of organophosphate flame retardants (OPFRs) on neutrophils. Previous literature outlined that neutrophil extracellular traps (NETs) death (NETosis) is associated with autophagy-related signaling. Here we found that 20 µM diphenyl phosphate (DPHP) could promote NETs formation via assessing markers of NETs and the morphological changes. Concurrently, flow cytometry and western blot analysis revealed that DPHP-triggered NETs formation was associated with reactive oxygen species (ROS) burst and activation of extracellular signal-regulated kinase (ERK) and p38. Additionally, the results revealed that autophagy occurred in DPHP-triggered NETs formation, manifested as enhanced LC3B protein expressions and reduced p62 protein expressions. Mechanism dissection revealed that inhibition of autophagy by 3-methyladenine (3-MA) alleviated the ROS burst and subsequent NETosis caused by DPHP. Conversely, autophagy enhancer Rapamycin (Rapa) augmented the above effects of DPHP, including the generation of ROS and NETosis. Collectively, these data suggested ERK/p38 signaling and ROS burst might be an important cause of DPHP-triggered NETs formation, while suppression of excessive autophagy could rescue these actions. These observations provided a theoretical basis for the treatment and prevention of OPFRs-induced immunotoxicity.


Assuntos
Armadilhas Extracelulares , Autofagia , Compostos de Bifenilo , MAP Quinases Reguladas por Sinal Extracelular , Organofosfatos , Fosfatos , Espécies Reativas de Oxigênio
2.
Front Immunol ; 12: 689866, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34737734

RESUMO

Rapid recruitment of neutrophils to an inflamed site is one of the hallmarks of an effective host defense mechanism. The main pathway through which this happens is by the innate immune response. Neutrophils, which play an important part in innate immune defense, migrate into lungs through the modulation actions of chemokines to execute a variety of pro-inflammatory functions. Despite the importance of chemokines in host immunity, little has been discussed on their roles in host immunity. A holistic understanding of neutrophil recruitment, pattern recognition pathways, the roles of chemokines and the pathophysiological roles of neutrophils in host immunity may allow for new approaches in the treatment of infectious and inflammatory disease of the lung. Herein, this review aims at highlighting some of the developments in lung neutrophil-immunity by focusing on the functions and roles of CXC/CC chemokines and pattern recognition receptors in neutrophil immunity during pulmonary inflammations. The pathophysiological roles of neutrophils in COVID-19 and thromboembolism have also been summarized. We finally summarized various neutrophil biomarkers that can be utilized as prognostic molecules in pulmonary inflammations and discussed various neutrophil-targeted therapies for neutrophil-driven pulmonary inflammatory diseases.


Assuntos
Imunidade Inata/imunologia , Neutrófilos/imunologia , Pneumonia/imunologia , Biomarcadores/sangue , COVID-19/imunologia , Degranulação Celular/imunologia , Quimiocinas/imunologia , Ensaios Clínicos como Assunto , Armadilhas Extracelulares/imunologia , Humanos , Integrinas/imunologia , Pulmão/imunologia , Pulmão/patologia , Neutrófilos/efeitos dos fármacos , Pneumonia/diagnóstico , Pneumonia/tratamento farmacológico , Receptores de Reconhecimento de Padrão/imunologia , Explosão Respiratória/imunologia , SARS-CoV-2 , Tromboembolia/imunologia
3.
Braz J Biol ; 83: e248717, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34669797

RESUMO

The human respiratory syncytial virus (hRSV) is the most common cause of severe lower respiratory tract diseases in young children worldwide, leading to a high number of hospitalizations and significant expenditures for health systems. Neutrophils are massively recruited to the lung tissue of patients with acute respiratory diseases. At the infection site, they release neutrophil extracellular traps (NETs) that can capture and/or inactivate different types of microorganisms, including viruses. Evidence has shown that the accumulation of NETs results in direct cytotoxic effects on endothelial and epithelial cells. Neutrophils stimulated by the hRSV-F protein generate NETs that are able to capture hRSV particles, thus reducing their transmission. However, the massive production of NETs obstructs the airways and increases disease severity. Therefore, further knowledge about the effects of NETs during hRSV infections is essential for the development of new specific and effective treatments. This study evaluated the effects of NETs on the previous or posterior contact with hRSV-infected Hep-2 cells. Hep-2 cells were infected with different hRSV multiplicity of infection (MOI 0.5 or 1.0), either before or after incubation with NETs (0.5-16 µg/mL). Infected and untreated cells showed decreased cellular viability and intense staining with trypan blue, which was accompanied by the formation of many large syncytia. Previous contact between NETs and cells did not result in a protective effect. Cells in monolayers showed a reduced number and area of syncytia, but cell death was similar in infected and non-treated cells. The addition of NETs to infected tissues maintained a similar virus-induced cell death rate and an increased syncytial area, indicating cytotoxic and deleterious damages. Our results corroborate previously reported findings that NETs contribute to the immunopathology developed by patients infected with hRSV.


Assuntos
Armadilhas Extracelulares , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Pré-Escolar , Células Epiteliais , Humanos , Pulmão
4.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 38(5): 903-910, 2021 Oct 25.
Artigo em Chinês | MEDLINE | ID: mdl-34713658

RESUMO

Neutrophil extracellular traps (NETs) play an important role in the formation of immunothrombosis. However, how vascular endothelial cells mediate the formation of NETs has not been fully understood. We stimulated neutrophils firmly attached on the endothelial cell surface intercellular adhesion molecule-1 (ICAM-1) with lipopolysaccharide (LPS) or phorbol-12-myristate-13-acetate (PMA) for 4 h, then labeled NETs-DNA with Sytox green dye and the formation of NETs was observed by fluorescent microscopy. The area and fluorescence intensity of NETs-DNA were analyzed to quantify the formation of NETs. The results showed that both PMA and LPS were able to induce firmly adhered neutrophils on ICAM-1 to produce NETs. NETs induced by PMA were independent of neither ß2 integrin lymphocyte function-associated antigen-1 (LFA-1) nor macrophage antigen complex-1 (Mac-1). In contrast, LPS-stimulated NETs were mediated by Mac-1 integrin, but not by LFA-1. After inhibition of actin filaments or Talin-1, the formation of NETs irrespective of the stimulus was significantly reduced. This study reveals the mechanism of the direct interaction between neutrophils and endothelial cells to produce NETs under inflammatory conditions, providing a new theoretical basis for the treatment of related diseases and the development of new drugs.


Assuntos
Armadilhas Extracelulares , Proteínas do Citoesqueleto , Células Endoteliais , Integrinas , Molécula 1 de Adesão Intercelular , Lipopolissacarídeos/farmacologia , Macrófagos , Neutrófilos
5.
Front Immunol ; 12: 675315, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34616390

RESUMO

Neutrophil extracellular trap (NET) formation has emerged as an important response against various pathogens; it also plays a role in chronic inflammation, autoimmunity, and cancer. Despite a growing understanding of the mechanisms underlying NET formation, much remains to be elucidated. We previously showed that in human neutrophils activated with different classes of physiological stimuli, NET formation features both early and late events that are controlled by discrete signaling pathways. However, the nature of these events has remained elusive. We now report that PAD4 inhibition only affects the early phase of NET generation, as do distinct signaling intermediates (TAK1, MEK, p38 MAPK). Accordingly, the inducible citrullination of residue R2 on histone H3 is an early neutrophil response that is regulated by these kinases; other arginine residues on histones H3 and H4 do not seem to be citrullinated. Conversely, elastase blockade did not affect NET formation by several physiological stimuli, though it did so in PMA-activated cells. Among belated events in NET formation, we found that chromatin decondensation is impaired by the inhibition of signaling pathways controlling both early and late stages of the phenomenon. In addition to chromatin decondensation, other late processes were uncovered. For instance, unstimulated neutrophils can condition themselves to be poised for rapid NET induction. Similarly, activated neutrophils release endogenous proteic factors that promote and largely mediate NET generation. Several such factors are known RAGE ligands and accordingly, RAGE inbibition largely prevents both NET formation and the conditioning of neutrophils to rapidly generate NETs upon stimulation. Our data shed new light on the cellular processes underlying NET formation, and unveil unsuspected facets of the phenomenon that could serve as therapeutic targets. In view of the involvement of NETs in both homeostasis and several pathologies, our findings are of broad relevance.


Assuntos
Antígenos de Neoplasias/imunologia , Citrulinação/imunologia , Armadilhas Extracelulares/imunologia , Proteínas Quinases Ativadas por Mitógeno/imunologia , Neutrófilos/imunologia , Antígenos de Neoplasias/genética , Cromatina/imunologia , Citrulinação/genética , Armadilhas Extracelulares/genética , Histonas/imunologia , Humanos , Ligantes , Proteínas Quinases Ativadas por Mitógeno/genética , Neutrófilos/citologia , Transdução de Sinais
6.
Int J Mol Sci ; 22(19)2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34638724

RESUMO

The ocular surface is a gateway that contacts the outside and receives stimulation from the outside. The corneal innate immune system is composed of many types of cells, including epithelial cells, fibroblasts, natural killer cells, macrophages, neutrophils, dendritic cells, mast cells, basophils, eosinophils, mucin, and lysozyme. Neutrophil infiltration and degranulation occur on the ocular surface. Degranulation, neutrophil extracellular traps formation, called NETosis, and autophagy in neutrophils are involved in the pathogenesis of ocular surface diseases. It is necessary to understand the role of neutrophils on the ocular surface. Furthermore, there is a need for research on therapeutic agents targeting neutrophils and neutrophil extracellular trap formation for ocular surface diseases.


Assuntos
Degranulação Celular , Córnea/metabolismo , Armadilhas Extracelulares/metabolismo , Oftalmopatias/metabolismo , Infiltração de Neutrófilos , Neutrófilos/metabolismo , Córnea/patologia , Oftalmopatias/patologia , Humanos , Neutrófilos/patologia
7.
J Agric Food Chem ; 69(43): 12862-12869, 2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34694797

RESUMO

T-2 toxin (T-2) is a kind of trichothecene toxin produced from Fusarium fungi, which is an environmental pollutant that endangers poultry and human health. Heterophil extracellular traps (HETs) are not only a form of chicken immune defense against pathogen infection but also involved in pathophysiological mechanisms of several diseases. However, the immunotoxicity of T-2 on HET formation in vitro has not yet been reported. In this study, heterophils were exposed to T-2 at doses of 20, 40, and 80 ng/mL for 90 min. Observation of the structure of HETs by immunofluorescence staining and the mechanism of HET formation was analyzed by inhibitors and PicoGreen. These results showed that T-2-triggered HET formation consisted of DNA, elastase, and citH3. Furthermore, T-2 increased reactive oxygen species (ROS) generation, and the formation of T-2-triggered HETs was also decreased by the inhibitors of glycolysis, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, p38 and extracellular signal-regulated kinase (ERK)1/2 signaling pathways, suggesting that T-2-induced HETs are associated with glycolysis, ROS production, ERK1/2 and p38 signaling pathways, and NADPH oxidase. Taken together, this study elucidates the mechanism of T-2-triggered HET formation, and it may provide new insight into understanding the immunotoxicity of T-2 to early innate immunity in chickens.


Assuntos
Armadilhas Extracelulares , Toxina T-2 , Animais , Galinhas/metabolismo , Armadilhas Extracelulares/metabolismo , Glicólise , Humanos , Sistema de Sinalização das MAP Quinases , NADPH Oxidases/genética , NADPH Oxidases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Toxina T-2/metabolismo , Toxina T-2/toxicidade
8.
Nat Cell Biol ; 23(10): 1060-1072, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34616019

RESUMO

Eosinophilic inflammation is a feature of allergic asthma. Despite mounting evidence showing that chromatin filaments released from neutrophils mediate various diseases, the understanding of extracellular DNA from eosinophils is limited. Here we show that eosinophil extracellular traps (EETs) in bronchoalveolar lavage fluid are associated with the severity of asthma in patients. Functionally, we find that EETs augment goblet-cell hyperplasia, mucus production, infiltration of inflammatory cells and expressions of type 2 cytokines in experimental non-infection-related asthma using both pharmaceutical and genetic approaches. Multiple clinically relevant allergens trigger EET formation at least partially via thymic stromal lymphopoietin in vivo. Mechanically, EETs activate pulmonary neuroendocrine cells via the CCDC25-ILK-PKCα-CRTC1 pathway, which is potentiated by eosinophil peroxidase. Subsequently, the pulmonary neuroendocrine cells amplify allergic immune responses via neuropeptides and neurotransmitters. Therapeutically, inhibition of CCDC25 alleviates allergic inflammation. Together, our findings demonstrate a previously unknown role of EETs in integrating immunological and neurological cues to drive asthma progression.


Assuntos
Asma/patologia , Líquido da Lavagem Broncoalveolar/imunologia , Eosinófilos/patologia , Armadilhas Extracelulares/fisiologia , Inflamação/patologia , Pulmão/patologia , Células Neuroendócrinas/patologia , Adulto , Animais , Asma/etiologia , Asma/metabolismo , Estudos de Casos e Controles , Eosinófilos/imunologia , Eosinófilos/metabolismo , Feminino , Humanos , Inflamação/etiologia , Inflamação/metabolismo , Pulmão/imunologia , Pulmão/metabolismo , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Neuroendócrinas/imunologia , Células Neuroendócrinas/metabolismo , Neutrófilos/imunologia , Neutrófilos/metabolismo , Neutrófilos/patologia , Proteína Quinase C-alfa/genética , Proteína Quinase C-alfa/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
9.
Cells ; 10(10)2021 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-34685525

RESUMO

The coronavirus disease 2019 (COVID-19) is related to enhanced production of NETs, and autoimmune/autoinflammatory phenomena. We evaluated the proportion of low-density granulocytes (LDG) by flow cytometry, and their capacity to produce NETs was compared with that of conventional neutrophils. NETs and their protein cargo were quantified by confocal microscopy and ELISA. Antinuclear antibodies (ANA), anti-neutrophil cytoplasmic antibodies (ANCA) and the degradation capacity of NETs were addressed in serum. MILLIPLEX assay was used to assess the cytokine levels in macrophages' supernatant and serum. We found a higher proportion of LDG in severe and critical COVID-19 which correlated with severity and inflammatory markers. Severe/critical COVID-19 patients had higher plasmatic NE, LL-37 and HMGB1-DNA complexes, whilst ISG-15-DNA complexes were lower in severe patients. Sera from severe/critical COVID-19 patients had lower degradation capacity of NETs, which was reverted after adding hrDNase. Anti-NET antibodies were found in COVID-19, which correlated with ANA and ANCA positivity. NET stimuli enhanced the secretion of cytokines in macrophages. This study unveils the role of COVID-19 NETs as inducers of pro-inflammatory and autoimmune responses. The deficient degradation capacity of NETs may contribute to the accumulation of these structures and anti-NET antibodies are related to the presence of autoantibodies.


Assuntos
Autoimunidade , COVID-19/sangue , COVID-19/imunologia , Armadilhas Extracelulares/imunologia , Imunidade Humoral , Inflamação , Neutrófilos/imunologia , Anticorpos Antinucleares , Peptídeos Catiônicos Antimicrobianos/sangue , Autoanticorpos/metabolismo , Estudos Transversais , Citocinas/metabolismo , Citocinas/farmacologia , Citometria de Fluxo , Granulócitos/metabolismo , Proteína HMGB1/sangue , Voluntários Saudáveis , Humanos , Microscopia Confocal , Monócitos/citologia , Neutrófilos/citologia , SARS-CoV-2 , Ubiquitinas/farmacologia
10.
Front Cell Infect Microbiol ; 11: 694186, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34568088

RESUMO

The severity of coronavirus disease 19 (COVID-19) is associated with neutrophil extracellular trap (NET) formation. During NET formation, cytotoxic extracellular histones are released, the presence of which is linked to the initiation and progression of several acute inflammatory diseases. Here we study the presence and evolution of extracellular histone H3 and several other neutrophil-related molecules and damage-associated molecular patterns (DAMPs) in the plasma of 117 COVID-19-positive ICU patients. We demonstrate that at ICU admission the levels of histone H3, MPO, and DNA-MPO complex were all significantly increased in COVID-19-positive patients compared to control samples. Furthermore, in a subset of 54 patients, the levels of each marker remained increased after 4+ days compared to admission. Histone H3 was found in 28% of the patients on admission to the ICU and in 50% of the patients during their stay at the ICU. Notably, in 47% of histone-positive patients, we observed proteolysis of histone in their plasma. The overall presence of histone H3 during ICU stay was associated with thromboembolic events and secondary infection, and non-cleaved histone H3 was associated with the need for vasoactive treatment, invasive ventilation, and the development of acute kidney injury. Our data support the validity of treatments that aim to reduce NET formation and additionally underscore that more targeted therapies focused on the neutralization of histones should be considered as treatment options for severe COVID-19 patients.


Assuntos
COVID-19 , Armadilhas Extracelulares , Histonas , Humanos , Unidades de Terapia Intensiva , SARS-CoV-2
11.
World J Gastroenterol ; 27(33): 5474-5487, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34588746

RESUMO

Gastrointestinal (GI) cancer is a high-risk malignancy and is characterized by high mortality and morbidity worldwide. Neutrophil extracellular traps (NETs), a weblike structure consisting of chromatin DNA with interspersed cytoplasmic and granule proteins, are extruded by activated neutrophils to entrap and kill bacteria and fungi. However, accumulating evidence shows that NETs are related to the progression and metastasis of cancer. In clinical studies, NETs infiltrate primary GI cancer tissues and are even more abundant in metastatic lesions. The quantity of NETs in peripheral blood is revealed to be associated with ascending clinical tumour stages, indicating the role of NETs as a prognostic markers in GI cancer. Moreover, several inhibitors of NETs or NET-related proteins have been discovered and used to exert anti-tumour effects in vitro or in vivo, suggesting that NETs can be regarded as targets in the treatment of GI cancer. In this review, we will focus on the role of NETs in gastric cancer and colorectal cancer, generalizing their effects on tumour-related thrombosis, invasion and metastasis. Recent reports are also listed to show the latest evidences of how NETs affect GI cancer. Additionally, notwithstanding the scarcity of systematic studies elucidating the underlying mechanisms of the interaction between NETs and cancer cells, we highlight the potential importance of NETs as biomarkers and anti-tumour therapeutic targets.


Assuntos
Armadilhas Extracelulares , Neoplasias Gastrointestinais , Trombose , Biomarcadores , Humanos , Neutrófilos
12.
Front Immunol ; 12: 689966, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34566957

RESUMO

Background: Most of the explanatory and prognostic models of COVID-19 lack of a comprehensive assessment of the wide COVID-19 spectrum of abnormalities. The aim of this study was to unveil novel biological features to explain COVID-19 severity and prognosis (death and disease progression). Methods: A predictive model for COVID-19 severity in 121 patients was constructed by ordinal logistic regression calculating odds ratio (OR) with 95% confidence intervals (95% CI) for a set of clinical, immunological, metabolomic, and other biological traits. The accuracy and calibration of the model was tested with the area under the curve (AUC), Somer's D, and calibration plot. Hazard ratios with 95% CI for adverse outcomes were calculated with a Cox proportional-hazards model. Results: The explanatory variables for COVID-19 severity were the body mass index (BMI), hemoglobin, albumin, 3-Hydroxyisovaleric acid, CD8+ effector memory T cells, Th1 cells, low-density granulocytes, monocyte chemoattractant protein-1, plasma TRIM63, and circulating neutrophil extracellular traps. The model showed an outstanding performance with an optimism-adjusted AUC of 0.999, and Somer's D of 0.999. The predictive variables for adverse outcomes in COVID-19 were severe and critical disease diagnosis, BMI, lactate dehydrogenase, Troponin I, neutrophil/lymphocyte ratio, serum levels of IP-10, malic acid, 3, 4 di-hydroxybutanoic acid, citric acid, myoinositol, and cystine. Conclusions: Herein, we unveil novel immunological and metabolomic features associated with COVID-19 severity and prognosis. Our models encompass the interplay among innate and adaptive immunity, inflammation-induced muscle atrophy and hypoxia as the main drivers of COVID-19 severity.


Assuntos
COVID-19 , SARS-CoV-2 , Índice de Gravidade de Doença , Adulto , Coagulação Sanguínea , Índice de Massa Corporal , COVID-19/sangue , COVID-19/imunologia , COVID-19/metabolismo , Citocinas/sangue , Armadilhas Extracelulares/imunologia , Feminino , Hemoglobinas/análise , Humanos , Masculino , Metaboloma , Pessoa de Meia-Idade , Atrofia Muscular , Neutrófilos/imunologia , Fenótipo , Prognóstico , Albumina Sérica Humana/análise , Linfócitos T/imunologia , Valeratos/sangue
13.
Int J Mol Sci ; 22(17)2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34502066

RESUMO

Introduction: This review explores angiogenesis, vascular dysfunction, the complement system, RAAS, apoptosis and NETosis as potential pathways that are dysregulated during preeclampsia, HIV infection and ART usage. Results: HIV-1 accessory and matrix proteins are protagonists for the elevation of oxidative stress, apoptosis, angiogenesis, and elevation of adhesion markers. Despite the immunodeficiency during HIV-1 infection, HIV-1 exploits our cellular defence arsenal by escaping cell-mediated lysis, yet HIV-1 infectivity is enhanced via C5a release of TNF-α and IL-6. This review demonstrates that PE is an oxidatively stressed microenvironment associated with increased apoptosis and NETosis, but with a decline in angiogenesis. Immune reconstitution in the duality of HIV-1 and PE by protease inhibitors, HAART and nucleoside reverse transcriptase, affect similar cellular pathways that eventuate in loss of endothelial cell integrity and, hence, its dysfunction. Conclusions: HIV-1 infection, preeclampsia and ARTs differentially affect endothelial cell function. In the synergy of both conditions, endothelial dysfunction predominates. This knowledge will help us to understand the effect of HIV infection and ART on immune reconstitution in preeclampsia.


Assuntos
Infecções por HIV/complicações , Pré-Eclâmpsia/metabolismo , Animais , Terapia Antirretroviral de Alta Atividade/efeitos adversos , Apoptose , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Endotélio Vascular/virologia , Armadilhas Extracelulares/metabolismo , Feminino , Humanos , Neovascularização Fisiológica , Estresse Oxidativo , Pré-Eclâmpsia/virologia , Gravidez
14.
Front Immunol ; 12: 668974, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34539623

RESUMO

Objectives: This aim of this study was to determine whether neutrophil extracellular traps (NETs) are involved in the pathogenesis of IgA vasculitis (IgAV) and investigate whether the circulating NETs levels are associated with disease activity in children. Methods: We performed a case-control study and collected blood samples from 193 children with different stages of IgAV (61 were at the onset stage, 64 at the remission stage, 43 at the active stage, and 25 were undergoing drug withdrawal). A total of 192 healthy children were recruited as controls. Circulating cell free DNA (cf-DNA) was obtained from the plasma and quantified by using the Quant-iT PicoGreen DNA quantification kit. NETs-associated myeloperoxidase-DNA (MPO-DNA), citrullinated-histone H3 (cit-H3), neutrophil elastase (NE), and the deoxyribonuclease I (DNase I) concentrations were measured using enzyme-linked immunosorbent assays. The presence of NETs in the kidney and gastrointestinal tissues of onset and active IgAV patients was determined by multiple immunofluorescence staining in 15 IgAV nephritis patients and 9 IgAV patients without IgAV nephritis, respectively. NETs degradation potency of collected sera samples from IgAV patients were checked in vitro. Relationships between circulating levels of cf-DNA with MPO-DNA, NE, and DNase I and the patients were analyzed. Results: Circulating levels of cf-DNA in onset and active IgAV patients were significantly higher than those in remission and drug withdrawal patients as well as healthy controls. The results were similar for MPO-DNA and NE. The levels of circulating cf-DNA correlated significantly with MPO-DNA, NE and DNase I. A significantly decreased degradation of NETs from the onset and active IgAV patients was observed, but was normal in healthy controls. Furthermore, presence of NETs was also confirmed in all renal and gastrointestinal tissues obtained from the onset and active IgAV patients but not control samples. Conclusions: Our data showed that NETs were released into the circulation of IgAV patients and are involved in the disease activity. The circulating levels of NETs maybe used to assess disease severity in children with IgAV.


Assuntos
Armadilhas Extracelulares/metabolismo , Imunoglobulina A/sangue , Neutrófilos/metabolismo , Púrpura de Schoenlein-Henoch/imunologia , Biomarcadores/sangue , Estudos de Casos e Controles , Ácidos Nucleicos Livres/sangue , Criança , Pré-Escolar , DNA/sangue , Feminino , Trato Gastrointestinal/imunologia , Trato Gastrointestinal/metabolismo , Humanos , Rim/imunologia , Rim/metabolismo , Masculino , Ativação de Neutrófilo , Neutrófilos/imunologia , Púrpura de Schoenlein-Henoch/sangue , Púrpura de Schoenlein-Henoch/diagnóstico , Púrpura de Schoenlein-Henoch/tratamento farmacológico , Índice de Gravidade de Doença
15.
ACS Nano ; 15(10): 15930-15939, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34586780

RESUMO

Neutrophils are crucial for host defense but are notorious for causing sterile inflammatory damage. Activated neutrophils in inflamed tissue can liberate histone H4, which was recently shown to perpetuate inflammation by permeating membranes via the generation of negative Gaussian curvature (NGC), leading to lytic cell death. Here, we show that it is possible to build peptides or proteins that cancel NGC in membranes and thereby suppress pore formation, and demonstrate that they can inhibit H4 membrane remodeling and thereby reduce histone H4-driven lytic cell death and resultant inflammation. As a demonstration of principle, we use apolipoprotein A-I (apoA-I) mimetic peptide apoMP1. X-ray structural studies and theoretical calculations show that apoMP1 induces nanoscopic positive Gaussian curvature (PGC), which interacts with the NGC induced by the N-terminus of histone H4 (H4n) to inhibit membrane permeation. Interestingly, we show that induction of PGC can inhibit membrane-permeating activity in general and "turn off" diverse membrane-permeating molecules besides H4n. In vitro experiments show an apoMP1 dose-dependent rescue of H4 cytotoxicity. Using a mouse model, we show that tissue accumulation of neutrophils, release of neutrophil extracellular traps (NETs), and extracellular H4 all strongly correlate independently with local tissue cell death in multiple organs, but administration of apoMP1 inhibits histone H4-mediated cytotoxicity and strongly prevents organ tissue damage.


Assuntos
Armadilhas Extracelulares , Neutrófilos , Morte Celular , Histonas , Peptídeos/farmacologia
16.
Int J Mol Sci ; 22(17)2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34502391

RESUMO

Extracellular Cold-inducible RNA-binding protein (eCIRP), a damage-associated molecular pattern, is released from cells upon hypoxia and cold-stress. The overall absence of extra- and intracellular CIRP is associated with increased angiogenesis, most likely induced through influencing leukocyte accumulation. The aim of the present study was to specifically characterize the role of eCIRP in ischemia-induced angiogenesis together with the associated leukocyte recruitment. For analyzing eCIRPs impact, we induced muscle ischemia via femoral artery ligation (FAL) in mice in the presence or absence of an anti-CIRP antibody and isolated the gastrocnemius muscle for immunohistological analyses. Upon eCIRP-depletion, mice showed increased capillary/muscle fiber ratio and numbers of proliferating endothelial cells (CD31+/CD45-/BrdU+). This was accompanied by a reduction of total leukocyte count (CD45+), neutrophils (MPO+), neutrophil extracellular traps (NETs) (MPO+CitH3+), apoptotic area (ascertained via TUNEL assay), and pro-inflammatory M1-like polarized macrophages (CD68+/MRC1-) in ischemic muscle tissue. Conversely, the number of regenerative M2-like polarized macrophages (CD68+/MRC1+) was elevated. Altogether, we observed that eCIRP depletion similarly affected angiogenesis and leukocyte recruitment as described for the overall absence of CIRP. Thus, we propose that eCIRP is mainly responsible for modulating angiogenesis via promoting pro-angiogenic microenvironmental conditions in muscle ischemia.


Assuntos
Isquemia/patologia , Neovascularização Fisiológica/fisiologia , Proteínas de Ligação a RNA/metabolismo , Animais , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Armadilhas Extracelulares/metabolismo , Inflamação/patologia , Isquemia/metabolismo , Contagem de Leucócitos , Leucócitos/metabolismo , Ativação de Macrófagos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos da Linhagem 129 , Músculos/metabolismo , Neutrófilos/metabolismo , Proteínas de Ligação a RNA/fisiologia
17.
Int J Mycobacteriol ; 10(3): 271-278, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34494566

RESUMO

Background: It has been reported that sera from patients with active pulmonary tuberculosis (APT) induced nuclear changes in normal neutrophils that included pyknosis, swelling, apoptosis, and production of extracellular traps (NETs). Similar changes were observed with some sera from their household contacts but not with sera from healthy, unrelated individuals. It was suggested that those sera from household contacts that induced neutrophil nuclear changes might correspond to people with subclinical tuberculosis. Thus, our experimental approach might serve to identify individuals with early, ongoing disease. Methods: Nuclear changes in neutrophils were fully evident by 3 h of contact and beyond. Circulating mycobacterial antigens were the most likely candidates for this effect. We wanted to know whether the nuclear changes induced on neutrophils by the sera of APT patients would negatively affect the phagocytic/microbicidal ability of neutrophils exposed to APT sera for short periods. Results: We now provide evidence that short-term contact (30 min) with sera from patients with pulmonary tuberculosis increases several phagocytic parameters of normal neutrophils, including endocytosis, myeloperoxidase levels, production of free reactive oxygen species, phagolysosome fusion, and microbicidal activity on Staphylococcus aureus, with these effects not being observed with sera from healthy donors. We also give evidence that suggests that ESAT-6 and CFP-10 are involved in the phenomenon. Conclusion: We conclude that activation is a stage that precedes lethal nuclear changes in neutrophils and suggests that autologous neutrophils must circulate in an altered state in the APT patients, thus contributing to the pathology of the disease.


Assuntos
Armadilhas Extracelulares , Mycobacterium tuberculosis , Tuberculose , Antígenos de Bactérias , Humanos , Neutrófilos
18.
Med Hypotheses ; 156: 110684, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34583310

RESUMO

Some of the COVID-19 patients present with ischemic lesions of their finger and toes. Standard anticoagulant therapy is usually unsuccessful for the treatment of this unique presentation of COVID-19. In this review current evidence is presented, which supports the hypothesis that these necrotic lesions are primarily related to the formation of neutrophil extracellular traps is blood vessels. Also, currently available and potential pharmacological methods of the management of this unique thrombotic complication are discussed. Drugs that possibly could be used in COVID-19 patients suffering from acute ischemia of distal parts of the extremities particularly comprise DNase I and DNase1L3, which could directly dissolve these extracellular webs that are mostly composed of DNA. However, at the moment, none of these enzymes are registered for an intravascular administration in humans. Lactoferrin and dipyridamole are other pharmaceutical agents that could potentially be used for the treatment of neutrophil extracellular traps-evoked digital ischemia. These agents exhibit prophylactic activity against excessive formation of these extracellular structures. Such an experimental treatment should probably be accompanied by standard antithrombotic management with heparin. Open-label and then randomized trials are needed to confirm feasibility, safety and efficacy of the above-suggested management of critically ill COVID-19 patients.


Assuntos
COVID-19 , Armadilhas Extracelulares , Trombose , Humanos , Necrose , Neutrófilos , SARS-CoV-2 , Trombose/tratamento farmacológico
19.
Ecotoxicol Environ Saf ; 225: 112779, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34530259

RESUMO

Polybrominated diphenyl ethers (PBDE-47), a kind of lipophilic persistent organic pollutants (POPs) brominated flame retardant, has been widely used in various consumer products. However, the toxicity of PBDE-47 on human immune system has not been well elucidated. Neutrophil extracellular traps (NETs) contribute to the innate immune responses, and the release of NETs is recognized as the most important part of the extracellular killing mechanism. The aim of this study was to investigate the effect of PBDE-47 on NETs and its possible molecular mechanism, as well as the intervention effect of curcumin (Cur). In this study, the formation of PBDE-47-induced NETs was observed by fluorescence microscopy and scanning electron microscopy, and was also quantitatively detected by DNA dye SYTOX green. In addition, we used Cur and Nrf2 inhibitor ML385 to explore the role of reactive oxygen species (ROS), extracellular signal regulated kinase (ERK) and p38 signaling pathway in PBDE-47-induced reticular formation. We demonstrated that PBDE-47 could significantly induce the formation of NETs, and its molecular mechanism might be related to ROS burst. Cur reduced ROS and inhibited PBDE-47-induced NETs formation by interfering with Nrf2. In conclusion, this study revealed that Cur hindered PBDE-47-induced NETs via Nrf2-associated ROS inhibition, which enriched the cytotoxicity mechanism of PBDE-47, and provided a new clue for the development of Cur as an antagonist of PBDE-47-related immune injury.


Assuntos
Curcumina , Armadilhas Extracelulares , Curcumina/farmacologia , Éteres Difenil Halogenados/toxicidade , Humanos , Fator 2 Relacionado a NF-E2/genética , Espécies Reativas de Oxigênio
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