Silver nanoparticles induce degradation of the endoplasmic reticulum stress sensor activating transcription factor-6 leading to activation of the NLRP-3 inflammasome.

In the past decade, the increasing amount of nanoparticles (NP) and nanomaterials used in multiple applications led the scientific community to investigate the potential toxicity of NP. Many studies highlighted the cytotoxic effects of various NP, including titanium dioxide, zinc oxide, and silver nanoparticles (AgNP). In a few studies, endoplasmic reticulum (ER) stress was found to be associated with NP cytotoxicity leading to apoptosis in different cell types. In this study, we report for the first time that silver nanoparticles of 15 nm (AgNP15), depending on the concentration, induced different signature ER stress markers in human THP-1 monocytes leading to a rapid ER stress response with degradation of the ATF-6 sensor. Also, AgNP15 induced pyroptosis and activation of the NLRP-3 inflammasome as demonstrated by the processing and increased activity of caspase-1 and secretion of IL-1ß and ASC (apoptosis-associated speck-like protein containing a CARD domain) pyroptosome formation. Transfection of THP-1 cells with siRNA targeting NLRP-3 decreased the AgNP15-induced IL-1ß production. The absence of caspase-4 expression resulted in a significant reduction of pro-IL-1ß. However, caspase-1 activity was significantly higher in caspase-4-deficient cells when compared with WT cells. Inhibition of AgNP15-induced ATF-6 degradation with Site-2 protease inhibitors completely blocked the effect of AgNP15 on pyroptosis and secretion of IL-1ß, indicating that ATF-6 is crucial for the induction of this type of cell death. We conclude that AgNP15 induce degradation of the ER stress sensor ATF-6, leading to activation of the NLRP-3 inflammasome regulated by caspase-4 in human monocytes.

Activation of human neutrophils by the anti-inflammatory mediator Esenbeckia leiocarpa leads to atypical apoptosis.

Despite the fact that Esenbeckia leiocarpa, a Brazilian plant, possesses potential anti-inflammatory properties, its effect in neutrophils, key players in inflammation, has never been investigated. In this study, a crude hydroalcoholic extract (CHE) was used to evaluate the potential toxic or agonistic effect of E. leiocarpa in human neutrophils. At a noncytotoxic concentration of 500 µg/mL, CHE increased actin polymerization and cell signaling events, especially p38 MAPK. Its modulatory activity on neutrophil cell apoptosis was investigated by cytology and by flow cytometry and, although CHE increased the apoptotic rate (by cytology) and increased annexin-V binding, it did not, unexpectedly, increase CD16 shedding. CHE increased the degradation of the cytoskeletal proteins gelsolin and paxillin but, surprisingly, not of vimentin. The proapoptotic activity of CHE was reversed by a pan-caspase inhibitor but not by a p38 inhibitor. We conclude that CHE is a novel human neutrophil agonist that induces apoptosis by a caspase-dependent and p38-independent mechanism in an atypical fashion based on its lack of effect on CD16 shedding and vimentin degradation. Since the resolution of inflammation occurs by elimination of apoptotic neutrophils, the ability of CHE to induce neutrophil apoptosis correlates well with its anti-inflammatory properties, as previously reported.

Activation of neutrophils by nanoparticles.

The use of nanoparticles (NPs) has increased in the past few years in various fields, including defence, aerospace, electronics, biology, medicine, and so forth. and in applications such as diagnostic technology, bioimaging, and drug/gene delivery. Thus, human exposure to NPs and nanomaterials is unavoidable and will certainly expand in the future resulting in a growing interest in nanotoxicology, the study of toxicity of nanomaterials. A number of studies have reported the effects of NPs in respect to pulmonary inflammation by investigating in vitro activation of pulmonary cells with NPs and in vivo in a variety of models in which neutrophils appear to be the predominant leukocyte cell type in lungs and in bronchoalveolar lavages following inhalation or intratracheal instillation of NPs. Despite the fact that several studies have reported an increased number of neutrophils, the literature dealing with the direct activation of neutrophils by a given NP is poorly documented. This paper will summarize the current literature in this latter area of research and will end with a perspective view in which our laboratory will be involved in the following years.

Efficacy of tacrolimus in inhibiting inflammation caused by carrageenan in a murine model of air pouch.

BACKGROUND: Tacrolimus (Tac) is a macrolide immunosuppressant drug isolated from Streptomyces tsukubaensis, widely used in organ transplantation. OBJECTIVE: This study examined the effect of tacrolimus administered by oral route (p.o.) on inflammation in mouse subcutaneous air pouch triggered by carrageenan (Cg 1%). METHODS: The air pouch was induced as described by Benincá et al. [Benincá JP, Montanher AB, Zucolotto SM, Schenkel EP, FrödeTS. Anti-inflammatory effects of the Passiflora edulis: forma flavicarpa Degener inhibition of leukocytes, enzymes and pro-inflammatory cytokine levels in the air pouch model, in mice. Food Chem 2007; 104(3); 1097-1105.]. The inflammatory parameters (leukocytes, exudation, myeloperoxidase (MPO) and adenosine-deaminase (ADA) activities, as well as nitrate/nitrate concentrations (NO(x)), interleukin-1 beta (IL-1beta), chemokine to neutrophil (KC) and tumor necrosis factor-alpha (TNF-alpha) levels were analysed 24 h after injection of carrageenan. RESULTS: Tacrolimus, indomethacin and dexamethasone significantly inhibited leukocytes, neutrophils and exudation (P<0.05) when they were administered 0.5 h before inflammation. These drugs, under the same conditions, decreased MPO and ADA activities (P<0.05), NO(x) and IL-1beta levels (P<0.01). Tacrolimus and indomethacin, but not dexamethasone, inhibited KC levels (P<0.01). On the other hand, tacrolimus and dexamethasone, but not indomethacin, decreased TNF-alpha levels (P<0.01). CONCLUSIONS: Results of this study indicate that tacrolimus has an important anti-inflammatory property, showing not only inhibition of pro-inflammatory mediators release, but also inhibition of activated leukocyte infiltration into the site of inflammation. Furthermore, these results showed that most of the anti-inflammatory actions of tacrolimus were similar to those observed in animals treated with either indomethacin or dexamethasone.

The anti-inflammatory modulatory role of Solidago chilensis Meyen in the murine model of the air pouch.

The aim of this study was to investigate the anti-inflammatory efficacy of an aqueous extract (AE), and its butanolic (BuOH) and aqueous residual (AR) fractions, derived from the rhizome of Solidago chilensis in inflammation caused by carrageenan in mice. Solidago chilensis Meyen rhizome was extracted using hot water at 90 degrees C under infusion. The extract was filtered and lyophilized. Part of the aqueous extract was fractionated with n-BuOH, resulting in butanolic (BuOH) and aqueous residual (AR) fractions. Adult Swiss mice were used in the in-vivo experiments. We evaluated the effect of rhizome aqueous extract of Solidago chilensis and these two derived fractions on the inflammation induced by carrageenan in the mouse model of the air pouch. The aqueous extract and its derived fractions significantly inhibited leucocytes, neutrophils, exudation, myeloperoxidase and adenosine deaminase activity, as well as nitric oxide, interleukin-1 beta (IL-1beta), neutrophil chemokine (KC) and tumour necrosis factor-alpha (TNF-alpha) levels (P < 0.05). Indometacin and dexamethasone inhibited all the studied inflammatory parameters (P < 0.01) with the exceptions that indometacin did not inhibit TNF-alpha levels and dexamethasone did not inhibit KC levels (P > 0.05). These results indicate that Solidago chilensis has a significant anti-inflammatory action on acute inflammatory responses and that its inhibitory activity may be due not only to the inhibition of proinflammatory mediators, but also to the inhibition of leucocyte infiltration.

Anti-inflammatory evaluation of Solidago chilensis Meyen in a murine model of pleurisy.

UNLABELLED: The aim of this study was to investigate the anti-inflammatory effects and the mechanism of action of the aqueous extracts obtained from rhizomes, leaves and inflorescences of Solidago chilensis in the mouse model of pleurisy. The extracts were prepared by infusion and were lyophilized. RESULTS: The aqueous extracts of rhizomes, leaves or inflorescences inhibited leukocytes, neutrophils and exudation (P<0.05) in the inflammation induced by carrageenan. The rhizomes aqueous extract, butanolic and aqueous residual fractions inhibited leukocytes, neutrophils, myeloperoxidase, adenosine-deaminase, and tumor necrosis factor alpha levels in the inflammation induced by carrageenan (P<0.05). The rhizome aqueous extract and butanolic fraction also inhibited exudation, nitric oxide, and interleukin-1 beta levels (P<0.05). The rhizomes aqueous extract and its two derived fractions reduced leukocytes and mononuclears in the pleurisy induced by bradykinin, histamine, or substance P (P<0.05) and neutrophils in the pleurisy induced by histamine or substance P (P<0.05). Only aqueous residual fraction inhibited neutrophils induced by bradykinin (P<0.05). CONCLUSION: Solidago chilensis aqueous extracts from leaves, inflorescences and rhizomes demonstrated an important anti-inflammatory effect, inhibiting cells in the inflammation caused by carrageenan. In addition, the rhizomes aqueous extract and its derived fractions also decreased pro-inflammatory mediators release into the site of the inflammatory process. The rhizomes aqueous extract and the butanolic fraction showed more evident anti-inflammatory actions.

Silver nanoparticles rapidly induce atypical human neutrophil cell death by a process involving inflammatory caspases and reactive oxygen species and induce neutrophil extracellular traps release upon cell adhesion.

Inflammation is one of the major toxic effects reported in response to in vitro or in vivo nanoparticle (NP) exposure. Among engineered NPs, silver nanoparticles (AgNPs) are very attractive for the development of therapeutic strategies, especially because of their antimicrobial properties. In humans, neutrophils, key players in inflammation, are the most abundant blood leukocytes that spontaneously undergo apoptosis, a central cell death mechanism regulating inflammation. The aim of this study was to evaluate the effect of AgNPs on neutrophil apoptosis. Transmission electronic microscopy reveals that AgNPs rapidly penetrate inside neutrophils. AgNPs induced atypical cell death where the cell volume increased and the cell surface expression of CD16 remained unaltered unlike apoptotic neutrophils where cell shrinkage and loss of CD16 are typically observed. The AgNP-induced atypical cell death is distinct from necrosis and reversed by a pancaspase inhibitor or by inhibitors of the inflammatory caspase-1 and caspase-4. In addition, AgNPs induced IL-1ß production inhibited by caspase-1 and caspase-4 inhibitors and also induced caspase-1 activity. Reactive oxygen species (ROS) production was increased by AgNPs and the atypical cell death was inhibited by the antioxidant n-acetylcysteine. Under similar experimental conditions, adhesion of neutrophils leads to neutrophil extracellular trap (NET) release induced by AgNPs. However, this process was not reversed by caspase inhibitors. We conclude that AgNPs rapidly induced an atypical cell death in neutrophils by a mechanism involving caspase-1, -4 and ROS. However, in adherent neutrophils, AgNPs induced NET release and, therefore, are novel agents able to trigger NET release.

Acute effect of ß-sitosterol on calcium uptake mediates anti-inflammatory effect in murine activated neutrophils.

OBJECTIVES: To evaluate the effect of ß-sitosterol on 45Ca²âº uptake in activated murine neutrophils, and upon myeloperoxidase and adenosine deaminase activity, and interleukin-1ß (IL-1ß) and tumour necrosis factor-α (TNF-α) levels, in carrageenan-induced inflammation in the mouse air pouch model. METHODS: Dried Esenbeckia leiocarpa bark was macerated and extracted resulting in a crude hydroalcoholic extract (CHE) that was partitioned to obtain an alkaloid fraction. The alkaloid was then partitioned in polar and nonpolar subfractions. ß-Sitosterol was isolated from the nonpolar subfraction and identified by comparison with the literature. The effect of ß-sitosterol on 45Ca²âº uptake in activated murine neutrophils, and upon myeloperoxidase and adenosine deaminase activity, IL-1ß and TNF-α levels in carrageenan-induced inflammation in mice were evaluated. KEY FINDINGS: ß-Sitosterol promoted a time- and dose-dependent increase of the calcium uptake in activated neutrophils that was promptly reversed by nifedipine, BAPTA-AM, LY294002, and colchicine. ß-Sitosterol inhibited myeloperoxidase and adenosine deaminase activity, and IL-1ß and TNF-α levels. CONCLUSIONS: ß-Sitosterol inhibited either myeloperoxidase and adenosine deaminase activity or IL-1ß and TNF-α levels. This effect seemed to be mediated by the calcium uptake in activated neutrophils in a time- and concentration-dependent manner through L-type voltage dependent calcium channels, intracellular calcium, phosphoinositide kinase-3, and microtubule modulation.

Percepções de usuários sobre o impacto social do projeto de cooperação do Programa Mais Médicos: um estudo de caso / Users' perceptions on social impact of the colaboration project of the More Doctors Program: a case study / Percepciones de usuarios sobre el impacto social del proyecto de cooperación del Programa Más Médicos: un estudio de caso

O estudo apresentado neste artigo objetiva identificar eventuais mudanças geradas no processo de cuidado de usuários da Atenção Básica, residentes em um município catarinense, contemplado com o Projeto de Cooperação do Programa Mais Médicos. Trata-se de um estudo qualitativo, realizado em 2015, que utilizou como instrumento de coleta de dados a entrevista semiestruturada e o diário de campo. A análise foi conduzida pelo método ético-político que revelou: a) uma produção consistente de vínculo, autorizada por um modo humanístico de pensar e fazer Medicina e pela internalização de ser cuidado por um igual, na condição de humanos; e b) insegurança sobre o término do projeto, edificada na desinformação. Conclui-se que o vínculo não prescinde de disposição solidária e que há necessidade de o Governo Federal efetivar um balizamento ético-político para garantir informação de qualidade sobre o projeto.(AU)

The study presented in this paper identifies probable changes generated in the care process of a primary healthcare service in a municipality of Santa Catarina, Brazil, part of the Collaboration Project of the More Doctors Program. This was a qualitative study conducted in 2015 that employed semi-structured interviews and a field diary as data collection instruments. Data analysis was performed through the ethical-political method, revealing: a) consistent creation of caring relationships, mediated by a humanistic mode of thinking and practicing medicine and internalization among members of the community of the belief that they were being cared for by an equal who was also a human being; and b) insecurity regarding the project's end, based on misinformation. This study concluded that a solidary disposition is essential to the creation of caring relationships, and that the federal government needs to implement ethicalpolitical guidelines to ensure quality information about the project.(AU)

El estudio presentado en este artículo tiene el objetivo de identificar eventuales cambios generados en el proceso de cuidado de usuarios de la Atención Básica, residentes en un municipio del Estado de Santa Catarina, Brasi, incluido en el Proyecto de Cooperación del Programa Más Médicos. Se trata de un estudio cualitativo, realizado en 2015, que utilizó como instrumento de colecta de datos la entrevista semi-estructurada y el diario de campo. El análisis fue realizado por el método ético-político que reveló: 1) una producción consistente de vínculo, autorizada por un modo humanístico de pensar y hacer medicina y por la internalización de ser cuidado por un igual, en la condición de humanos; y b) la inseguridad sobre el término del proyecto, edificada sobre la desinformación. Se concluyó que el vínculo no prescinde de disposición solidaria y que existe la necesidad de que el gobierno federal realice una señalización ético-política para asegurar información de calidad sobre el proyecto.(AU)

Activation of human neutrophils by Esenbeckia leiocarpa: comparison between the crude hydroalcoholic extract (CHE) and an alkaloid (Alk) fraction.

Esenbeckia leiocarpa, a wide spread native Brazilian tree, was reported recently to possess anti-inflammatory effects in vivo, but the mechanisms involved are still not fully understood and its role in neutrophils is poorly documented. The aim of this study was to compare the effects of a crude hydroalcoholic extract (CHE) and an alkaloid-enriched (Alk) fraction obtained from Esenbeckia leiocarpa bark on human neutrophils by investigating the effect of each fraction alone or in a mixture with classical neutrophil agonists. CHE inhibited intracellular reactive oxygen species (ROS) production but increased the extracellular superoxide (O2-) production, while Alk increased the former and also slightly increased O2- production. We found that CHE and Alk also induced phagocytosis accompanied by Syk activation, adhesion and degranulation. However, neither CHE nor Alk potentiated the effect of classical neutrophil agonists, namely the cytokines GM-CSF for phagocytosis and TNF-α for adhesion or N-formyl-methionyl-leucyl-phenylalanine (fMLP) for degranulation. In addition, based on catalase treatment, CHE and Alk induced neutrophil apoptosis by a hydrogen peroxide (H2O2)-dependent mechanism. Since the elimination of apoptotic neutrophils by professional phagocytes is important for the resolution of inflammation, the ability of CHE and Alk to induce neutrophil apoptosis has to be considered as one possible mechanism associated with the anti-inflammatory activity of these fractions previously reported in vivo.

Modulatory effect of mycophenolate mofetil on carrageenan-induced inflammation in the mouse air pouch model.

UNLABELLED: The treatment of some inflammatory diseases, such as rheumatoid arthritis, remains an important target for studies because some patients are refractory to conventional treatment. Mycophenolate mofetil (MMF), an immunosuppressive drug, has been shown to have a beneficial effect on the therapy of inflammatory and autoimmune diseases. In the present study, we aimed to analyse the anti-inflammatory effect of MMF administered by oral route in the mouse carrageenan-induced air pouch model. RESULTS: MMF significantly inhibited the influx of leukocytes, exudate concentrations (P<0.01), activities of myeloperoxidase (MPO) and adenosine deaminase (ADA), levels of nitrite/nitrate (NO(x)) and inducible nitric oxide synthase (iNOS) mRNA expression, as well as the levels of mRNA expression and proteins of tumor necrosis factor-alpha (TNF-α), Interleukin-beta (IL-1ß) and vascular endothelial growth factor-alpha (VEGF-α) (P<0.05). These results provide evidence that MMF has an important anti-inflammatory effect in reducing the influx of leukocytes and exudate concentrations. These inhibitory effects are correlated with the inhibition of specific pro-inflammatory enzymes (MPO, ADA and iNOS), and the levels of mRNA expression and proteins of TNF-α, IL-1ß and VEGF-α.

N-phenylmaleimide derivatives as mimetic agents of the pro-inflammatory process: myeloperoxidase activation.

Myeloperoxidase (MPO) is an important enzyme that catalyzes the reaction between hydrogen peroxide and chloride to generate hypochlorous acid, which oxidizes a range of biomolecules and has been associated with inflammatory diseases. The synthetic compounds N-phenylmaleimide (NFM) and 4-methyl-N-phenylmaleimide (Me-NFM) increased the MPO activity in vitro (of isolated enzyme and in isolated cells after animal treatment) and in vivo assays. MPO-induction may represent a good model system to investigate the molecular and cellular mechanisms of oxidative cell injury induced by activated neutrophils, and the interactions between damaging species involved in the respiratory burst.

Protected effect of Esenbeckia leiocarpa upon the inflammatory response induced by carrageenan in a murine air pouch model.

UNLABELLED: This study was conducted to investigate the anti-inflammatory efficacy of Esenbeckia leiocarpa against the inflammation caused by the carrageenan using a murine air pouch model. MATERIAL AND METHODS: The effects of the crude hydroalcoholic extract (CHE), fractions (n-hexane (Hex) and ethyl acetate (AcOEt)), subfractions (polar (Pol) and nonpolar (Nonpol)), or isolated compounds (dihydrocorynantheol (DHC) and beta-sitosterol (ß-Sit)) isolated from CHE upon leukocytes, exudate, myeloperoxidase (MPO) adenosine-deaminase (ADA), nitrate/nitrite (NO(x)), interleukin-1 beta (IL-1ß), tumor necrosis factor-alpha (TNF-α), and inhibitory kappa-B-alpha (IκB-α) degradation were evaluated. The CHE, Alk, Pol, Nonpol, DHC and ß-Sit, inhibited leukocytes, exudate, MPO and ADA, NO(x), IL-1ß, and TNF-α (P<0.05). The Hex and AcOEt fractions inhibited all of the proinflammatory parameters, except the exudate. The compound DHC prevented the IκB-α degradation. CONCLUSION: E. leiocarpa possesses important anti-inflammatory properties. These inhibitory effects occurred along with the downregulation of nitric oxide, IL-1ß and TNF-α levels. The isolated compounds DHC and ß-Sit may be partially responsible for these anti-inflammatory effects.