CARD8 polymorphisms among bacterial meningitis patients in North-West Ethiopia.

BACKGROUND: The severity of infectious disease outcomes is dependent on the virulence factors of the pathogen and the host immune response. CARD8 is a major regulator of the innate immune proinflammatory response and has been suggested to modulate the host response to common inflammatory diseases. In the present study, the C10X genetic polymorphism in the CARD8 gene was investigated in relation to bacterial meningitis. METHODS: A total of 400 clinically suspected meningitis patients hospitalized at the University of Gondar Hospital were enrolled in the study. Cerebrospinal fluid (CSF) and blood samples were collected for laboratory investigations. The collected CSF was cultured, and all the results obtained from the culture were confirmed using direct RT‒PCR. Genotyping of whole-blood samples was performed using a TaqMan assay. The results were compared with apparently healthy controls and with PCR-negative meningitis suspected patients. RESULTS: Of the included patients, 57% were men and the most common clinical signs and symptoms were fever (81%), headache (80%), neck stiffness (76%), nausea (68%), and vomiting (67%). Microbiology culture identified 7 patients with bacterial meningitis caused by Neisseria meningitidis (n = 4) and Streptococcus pneumoniae (n = 3). The RT-PCR revealed 39 positive samples for N. meningitidis (n = 10) and S. pneumoniae (n = 29). A total of 332 whole-blood samples were genotyped with the following results: 151 (45.5%) C10X heterozygotes, 59 (17.7%) C10X homozygotes and 122 (36.7%) wild genotypes. The polymorphic gene carriers among laboratory confirmed, clinically diagnosed meningitis and healthy controls were 23(46%), 246(40%), and 1526(39%), respectively with OR = 1.27 (0.7-2.3) and OR = 1.34 (0.76-2.4). The presence of the C10X polymorphism in the CARD8 gene was more prevalent in suspected meningitis patients than in healthy controls (OR 1.2; 1.00-1.5). Homozygote C10X polymorphic gene carriers were more susceptible to infectious disease. The presence of viable or active bacterial infection was found to be associated with the presence of heterozygous C10X carriers. CONCLUSIONS: A greater proportion of C10X in the CARD8 gene in confirmed bacterial meningitis patients and clinically diagnosed meningitis patients than in healthy controls. Homozygote C10X polymorphic gene carriers were more susceptible to infectious disease than heterozygote gene carriers and healthy controls.

Exposing kinetic disparities between inflammasome readouts using time-resolved analysis.

The NLRP3 inflammasome is an intracellular multiprotein complex described to be involved in both an effective host response to infectious agents and various diseases. Investigation into the NLRP3 inflammasome has been extensive in the past two decades, and often revolves around the analysis of a few specific readouts, including ASC-speck formation, caspase-1 cleavage or activation, and cleavage and release of IL-1ß and/or IL-18. Quantification of these readouts is commonly undertaken as an endpoint analysis, where the presence of each positive outcome is assessed independently of the others. In this study, we apply time-resolved analysis of a human macrophage model (differentiated THP-1-ASC-GFP cells) to commonly accessible methods. This approach yields the additional quantifiable metrics time-resolved absolute change and acceleration, allowing comparisons between readouts. Using this methodological approach, we reveal (potential) discrepancies between inflammasome-related readouts that otherwise might go undiscovered. The study highlights the importance of time-resolved data in general and may be further extended as well as incorporated into other areas of research.

Diverse proinflammatory response in pharyngeal epithelial cells upon interaction with Neisseria meningitidis carriage and invasive isolates.

BACKGROUND: Invasive meningococcal disease (IMD), including sepsis and meningitis, can develop when Neisseria meningitidis bacteria breach the barrier and gain access to the circulation. While IMD is a rare outcome of bacterial exposure, colonization of the oropharynx is present in approximately 10% of the human population. This asymptomatic carriage can be long or short term, and it is unknown which determining factors regulate bacterial colonization. Despite descriptions of many bacterial virulence factors and recent advances in detailed genetic identification and characterization of bacteria, the factors mediating invasion and disease vs. asymptomatic carriage following bacterial colonization remain unknown. The pharyngeal epithelia play a role in the innate immune defense against pathogens, and the aim of this study was to investigate the proinflammatory response of pharyngeal epithelial cells following meningococcal exposure to describe the potential inflammatory mediation performed during the initial host‒pathogen interaction. Clinically relevant isolates of serogroups B, C, W and Y, derived from patients with meningococcal disease as well as asymptomatic carriers, were included in the study. RESULTS: The most potent cellular response with proinflammatory secretion of TNF, IL-6, CXCL8, CCL2, IL-1ß and IL-18 was found in response to invasive serogroup B isolates. This potent response pattern was also mirrored by increased bacterial adhesion to cells as well as induced cell death. It was, however, only with serogroup B isolates where the most potent cellular response was toward the IMD isolates. In contrast, the most potent cellular response using serogroup Y isolates was directed toward the carriage isolates rather than the IMD isolates. In addition, by comparing isolates from outbreaks in Sweden (epidemiologically linked and highly genetically similar), we found the most potent proinflammatory response in cells exposed to carriage isolates rather than the IMD isolates. CONCLUSION: Although certain expected correlations between host‒pathogen interactions and cellular proinflammatory responses were found using IMD serogroup B isolates, our data indicate that carriage isolates invoke stronger proinflammatory activation of the epithelial lining than IMD isolates.

Immunotoxic, genotoxic, and endocrine disrupting impacts of polyamide microplastic particles and chemicals.

Due to their exceptional properties and cost effectiveness, polyamides or nylons have emerged as widely used materials, revolutionizing diverse industries, including industrial 3D printing or additive manufacturing (AM). Powder-based AM technologies employ tonnes of polyamide microplastics to produce complex components every year. However, the lack of comprehensive toxicity assessment of particulate polyamides and polyamide-associated chemicals, especially in the light of the global microplastics crisis, calls for urgent action. This study investigated the physicochemical properties of polyamide-12 microplastics used in AM, and assessed a number of toxicity endpoints focusing on inflammation, immunometabolism, genotoxicity, aryl hydrocarbon receptor (AhR) activation, endocrine disruption, and cell morphology. Specifically, microplastics examination by means of field emission scanning electron microscopy revealed that work flow reuse of material created a fraction of smaller particles with an average size of 1-5 µm, a size range readily available for uptake by human cells. Moreover, chemical analysis by means of gas chromatography high-resolution mass spectrometry detected several polyamide-associated chemicals including starting material, plasticizer, thermal stabilizer/antioxidant, and migrating slip additive. Even if polyamide particles and chemicals did not induce an acute inflammatory response, repeated and prolonged exposure of human primary macrophages disclosed a steady increase in the levels of proinflammatory chemokine Interleukin-8 (IL-8/CXCL-8). Moreover, targeted metabolomics disclosed that polyamide particles modulated the kynurenine pathway and some of its key metabolites. The p53-responsive luciferase reporter gene assay showed that particles per se were able to activate p53, being indicative of a genotoxic stress. Polyamide-associated chemicals triggered moderate activation of AhR and elicited anti-androgenic activity. Finally, a high-throughput and non-targeted morphological profiling by Cell Painting assay outlined major sites of bioactivity of polyamide-associated chemicals and indicated putative mechanisms of toxicity in the cells. These findings reveal that the increasing use of polyamide microplastics may pose a potential health risk for the exposed individuals, and it merits more attention.

Mathematical models disentangle the role of IL-10 feedbacks in human monocytes upon proinflammatory activation.

Inflammation is one of the vital mechanisms through which the immune system responds to harmful stimuli. During inflammation, proinflammatory and anti-inflammatory cytokines interplay to orchestrate fine-tuned and dynamic immune responses. The cytokine interplay governs switches in the inflammatory response and dictates the propagation and development of the inflammatory response. Molecular pathways underlying the interplay are complex, and time-resolved monitoring of mediators and cytokines is necessary as a basis to study them in detail. Our understanding can be advanced by mathematical models that enable to analyze the system of interactions and their dynamical interplay in detail. We, therefore, used a mathematical modeling approach to study the interplay between prominent proinflammatory and anti-inflammatory cytokines with a focus on tumor necrosis factor and interleukin 10 (IL-10) in lipopolysaccharide-primed primary human monocytes. Relevant time-resolved data were generated by experimentally adding or blocking IL-10 at different time points. The model was successfully trained and could predict independent validation data and was further used to perform simulations to disentangle the role of IL-10 feedbacks during an acute inflammatory event. We used the insight to obtain a reduced predictive model including only the necessary IL-10-mediated feedbacks. Finally, the validated reduced model was used to predict early IL-10-tumor necrosis factor switches in the inflammatory response. Overall, we gained detailed insights into fine-tuning of inflammatory responses in human monocytes and present a model for further use in studying the complex and dynamic process of cytokine-regulated acute inflammation.

NLRP3 inflammasome as a sensor of micro- and nanoplastics immunotoxicity.

Micro- and nanoplastics (MNPs) are emerging pollutants with scarcely investigated effects on human innate immunity. If they follow a similar course of action as other, more thoroughly investigated particulates, MNPs may penetrate epithelial barriers, potentially triggering a cascade of signaling events leading to cell damage and inflammation. Inflammasomes are intracellular multiprotein complexes and stimulus-induced sensors critical for mounting inflammatory responses upon recognition of pathogen- or damage-associated molecular patterns. Among these, the NLRP3 inflammasome is the most studied in terms of activation via particulates. However, studies delineating the ability of MNPs to affect NLRP3 inflammasome activation are still rare. In this review, we address the issue of MNPs source and fate, highlight the main concepts of inflammasome activation via particulates, and explore recent advances in using inflammasome activation for assessment of MNP immunotoxicity. We also discuss the impact of co-exposure and MNP complex chemistry in potential inflammasome activation. Development of robust biological sensors is crucial in order to maximize global efforts to effectively address and mitigate risks that MNPs pose for human health.

Occupational quartz and particle exposure affect systemic levels of inflammatory markers related to inflammasome activation and cardiovascular disease.

BACKGROUND: The inflammatory responses are central components of diseases associated with particulate matter (PM) exposure, including systemic diseases such as cardiovascular diseases (CVDs). The aim of this study was to determine if exposure to PM, including respirable dust or quartz in the iron foundry environment mediates systemic inflammatory responses, focusing on the NLRP3 inflammasome and novel or established inflammatory markers of CVDs. METHODS: The exposure to PM, including respirable dust, metals and quartz were determined in 40 foundry workers at two separate occasions per worker. In addition, blood samples were collected both pre-shift and post-shift and quantified for inflammatory markers. The respirable dust and quartz exposures were correlated to levels of inflammatory markers in blood using Pearson, Kendall τ and mixed model statistics. Analyzed inflammatory markers included: 1) general markers of inflammation, including interleukins, chemokines, acute phase proteins, and white blood cell counts, 2) novel or established inflammatory markers of CVD, such as growth/differentiation factor-15 (GDF-15), CD40 ligand, soluble suppressor of tumorigenesis 2 (sST2), intercellular/vascular adhesion molecule-1 (ICAM-1, VCAM-1), and myeloperoxidase (MPO), and 3) NLRP3 inflammasome-related markers, including interleukin (IL)-1ß, IL-18, IL-1 receptor antagonist (IL-1Ra), and caspase-1 activity. RESULTS: The average respirator adjusted exposure level to respirable dust and quartz for the 40 foundry workers included in the study was 0.65 and 0.020 mg/m3, respectively. Respirable quartz exposure correlated with several NLRP3 inflammasome-related markers, including plasma levels of IL-1ß and IL-18, and several caspase-1 activity measures in monocytes, demonstrating a reverse relationship. Respirable dust exposure mainly correlated with non-inflammasome related markers like CXCL8 and sST2. CONCLUSIONS: The finding that NLRP3 inflammasome-related markers correlated with PM and quartz exposure suggest that this potent inflammatory cellular mechanism indeed is affected even at current exposure levels in Swedish iron foundries. The results highlight concerns regarding the safety of current exposure limits to respirable dust and quartz, and encourage continuous efforts to reduce exposure in dust and quartz exposed industries.

A Novel Nanosafety Approach Using Cell Painting, Metabolomics, and Lipidomics Captures the Cellular and Molecular Phenotypes Induced by the Unintentionally Formed Metal-Based (Nano)Particles.

Additive manufacturing (AM) or industrial 3D printing uses cutting-edge technologies and materials to produce a variety of complex products. However, the effects of the unintentionally emitted AM (nano)particles (AMPs) on human cells following inhalation, require further investigations. The physicochemical characterization of the AMPs, extracted from the filter of a Laser Powder Bed Fusion (L-PBF) 3D printer of iron-based materials, disclosed their complexity, in terms of size, shape, and chemistry. Cell Painting, a high-content screening (HCS) assay, was used to detect the subtle morphological changes elicited by the AMPs at the single cell resolution. The profiling of the cell morphological phenotypes, disclosed prominent concentration-dependent effects on the cytoskeleton, mitochondria, and the membranous structures of the cell. Furthermore, lipidomics confirmed that the AMPs induced the extensive membrane remodeling in the lung epithelial and macrophage co-culture cell model. To further elucidate the biological mechanisms of action, the targeted metabolomics unveiled several inflammation-related metabolites regulating the cell response to the AMP exposure. Overall, the AMP exposure led to the internalization, oxidative stress, cytoskeleton disruption, mitochondrial activation, membrane remodeling, and metabolic reprogramming of the lung epithelial cells and macrophages. We propose the approach of integrating Cell Painting with metabolomics and lipidomics, as an advanced nanosafety methodology, increasing the ability to capture the cellular and molecular phenotypes and the relevant biological mechanisms to the (nano)particle exposure.

Particle Safety Assessment in Additive Manufacturing: From Exposure Risks to Advanced Toxicology Testing.

Additive manufacturing (AM) or industrial three-dimensional (3D) printing drives a new spectrum of design and production possibilities; pushing the boundaries both in the application by production of sophisticated products as well as the development of next-generation materials. AM technologies apply a diversity of feedstocks, including plastic, metallic, and ceramic particle powders with distinct size, shape, and surface chemistry. In addition, powders are often reused, which may change the particles' physicochemical properties and by that alter their toxic potential. The AM production technology commonly relies on a laser or electron beam to selectively melt or sinter particle powders. Large energy input on feedstock powders generates several byproducts, including varying amounts of virgin microparticles, nanoparticles, spatter, and volatile chemicals that are emitted in the working environment; throughout the production and processing phases. The micro and nanoscale size may enable particles to interact with and to cross biological barriers, which could, in turn, give rise to unexpected adverse outcomes, including inflammation, oxidative stress, activation of signaling pathways, genotoxicity, and carcinogenicity. Another important aspect of AM-associated risks is emission/leakage of mono- and oligomers due to polymer breakdown and high temperature transformation of chemicals from polymeric particles, both during production, use, and in vivo, including in target cells. These chemicals are potential inducers of direct toxicity, genotoxicity, and endocrine disruption. Nevertheless, understanding whether AM particle powders and their byproducts may exert adverse effects in humans is largely lacking and urges comprehensive safety assessment across the entire AM lifecycle-spanning from virgin and reused to airborne particles. Therefore, this review will detail: 1) brief overview of the AM feedstock powders, impact of reuse on particle physicochemical properties, main exposure pathways and protective measures in AM industry, 2) role of particle biological identity and key toxicological endpoints in the particle safety assessment, and 3) next-generation toxicology approaches in nanosafety for safety assessment in AM. Altogether, the proposed testing approach will enable a deeper understanding of existing and emerging particle and chemical safety challenges and provide a strategy for the development of cutting-edge methodologies for hazard identification and risk assessment in the AM industry.

Cytokine responses to LPS in reprogrammed monocytes are associated with the transcription factor PU.1.

Myeloid-derived suppressor cells (MDSCs) are functionally immunosuppressive cells that arise and expand during extensive inflammatory conditions by increased hematopoietic output or reprogramming of immune cells. In sepsis, an increase of circulating MDSCs is associated with adverse outcomes, but unique traits that can be used to identify increased activity of MDSCs are lacking. By using endotoxin tolerance as a model of sepsis-induced monocytic MDSCs (M-MDSC-like cells), this study aims to identify the mediator and transcriptional regulator profile associated with M-MDSC activity. After analyzing 180 inflammation-associated proteins, a profile of differentially expressed cytokines was found in M-MDSC-like cells versus normal monocytes stimulated with LPS. These cytokines were associated with 5 candidate transcription factors, where particularly PU.1 showed differential expression on both transcriptional and protein levels in M-MDSC-like cells. Furthermore, inhibition of PU.1 led to increased production of CXCL5 and CCL8 in M-MDSC-like cells indicating its role in regulating the ability of M-MDSC-like cells to recruit other immune cells. Taken together, the study identifies a unique profile in the pattern of immune mediators defining M-MDSC activity upon LPS stimulation, which offers a functional link to their contribution to immunosuppression.

Differential cytokine response in endotoxin induced M-MDSC-like cells and their associated regulators.

Toxicity evaluation of particles formed during 3D-printing: Cytotoxic, genotoxic, and inflammatory response in lung and macrophage models.

Additive manufacturing (AM) or "3D-printing" is a ground-breaking technology that enables the production of complex 3D parts. Its rapid growth calls for immediate toxicological investigations of possible human exposures in order to estimate occupational health risks. Several laser-based powder bed fusion AM techniques are available of which many use metal powder in the micrometer range as feedstock. Large energy input from the laser on metal powders generates several by-products, like spatter and condensate particles. Due to often altered physicochemical properties and composition, spatter and condensate particles can result in different toxicological responses compared to the original powder particles. The toxicity of such particles has, however, not yet been investigated. The aim of the present study was to investigate the toxicity of condensate/spatter particles formed and collected upon selective laser melting (SLM) printing of metal alloy powders, including a nickel-chromium-based superalloy (IN939), a nickel-based alloy (Hastelloy X, HX), a high-strength maraging steel (18Ni300), a stainless steel (316L), and a titanium alloy (Ti6Al4V). Toxicological endpoints investigated included cytotoxicity, generation of reactive oxygen species (ROS), genotoxicity (comet and micronucleus formation), and inflammatory response (cytokine/chemokine profiling) following exposure of human bronchial epithelial cells (HBEC) or monocytes/macrophages (THP-1). The results showed no or minor cytotoxicity in the doses tested (10-100 µg/mL). Furthermore, no ROS generation or formation of micronucleus was observed in the HBEC cells. However, an increase in DNA strand breaks (detected by comet assay) was noted in cells exposed to HX, IN939, and Ti6Al4V, whereas no evident release of pro-inflammatory cytokine was observed from macrophages. Particle and surface characterization showed agglomeration in solution and different surface oxide compositions compared to the nominal bulk content. The extent of released nickel was small and related to the nickel content of the surface oxides, which was largely different from the bulk content. This may explain the limited toxicity found despite the high Ni bulk content of several powders. Taken together, this study suggests relatively low acute toxicity of condensates/spatter particles formed during SLM-printing using IN939, HX, 18Ni300, 316L, and Ti6Al4V as original metal powders.

Effects on white blood cell counts and the NLRP3 inflammasome due to dust and cobalt exposure in the hard metal industry.

INTRODUCTION: In light of potential negative health effects of cobalt exposure, a characterization of inflammatory mechanisms in exposed individuals is warranted. The current study investigated cobalt exposure in the Swedish hard metal industry and its relationship to inflammatory markers, including NLRP3 inflammasome activation and white blood cell (WBC) counts. MATERIALS AND METHODS: Inhalable cobalt and dust exposures, and systemic cobalt levels, were determined for 72 workers in the hard metal industry and linear regression models were applied to correlate exposure to markers of inflammasome activation and WBC counts. RESULTS: Mean exposures to inhalable dust (0.11 mg/m3) and cobalt (0.0034 mg/m3) were below the Swedish occupational exposure limits, and these low exposures did not correlate with any investigated outcomes. Instead, cobalt blood levels significantly correlated with a ca 10% decrease in IL-18 plasma levels per 10 nM cobalt increase. Furthermore, pre-shift cobalt blood and/or urine levels significantly correlated with some WBC measures, including decreased neutrophil-to-lymphocyte ratio, increased lymphocyte-to-monocyte ratio, and lymphocyte counts. CONCLUSION: The low inhalable particle exposures had no impact on WBC counts and inflammasome activation. Instead, systemic cobalt levels, which also include skin exposure, demonstrated possible suppressive effects on inflammatory responses in cobalt-exposed individuals in the hard metal industry.

Dermal exposure to cobalt studied in vitro in keratinocytes - effects of cobalt exposure on inflammasome activated cytokines, and mRNA response.

BACKGROUND: Cobalt is a dermal sensitizer, and keratinocytes respond to cobalt exposure by releasing proinflammatory mediators, regulating the immune response. OBJECTIVE: To determine the effect of cobalt on the inflammasome associated cytokine- and gene expression in cultured human keratinocytes (HaCaT). Cultivation in low- or high calcium conditions model separate differentiation states of keratinocytes in the skin. METHOD: HaCaT cells in two different states of differentiation were exposed to cobalt chloride and caspase-1 activity as well as the production of IL-1ß, IL-18 and gene expression of IL1B, IL18, NLRP3, CASP1, and PYCARD was quantified. RESULTS: High cobalt chloride exposure mediated significant increase in caspase-1 activity, cytokine levels, and IL1B and NLRP3 expression with a corresponding regulatory decrease for CASP1 and PYCARD expression. No difference between high- and low calcium culturing conditions modelling differentiation states was detected. CONCLUSIONS: Our data suggest that HaCaT cells respond with inflammmasome associated activity upon cobalt exposure in a concentration-dependent manner. These mechanisms could be of importance for the understanding of the pathophysiology behind allergic sensitization to dermal cobalt exposure.

Dose- and time-dependent changes in viability and IL-6, CXCL8 and CCL2 production by HaCaT-cells exposed to cobalt. Effects of high and low calcium growth conditions.

BACKGROUND: Sensitization requires exposure to an allergen with subsequent production of a "danger "signal. In the skin, keratinocytes are the main producers of these signals. OBJECTIVE: To compare dose- and time-effects of cobalt on the viability of and cytokine release from HaCaT cells cultured at low or high calcium. METHOD: To model two separate states of differentiation of keratinocytes, HaCaT cells were cultured under low or high calcium conditions. HaCaT were exposed to different concentrations of cobalt chloride (10 µm to 5 mM) over time (30 minutes- 48 hours). Cell viability was measured with the Cell-Titer Blue Viability assay. Cytokine production was measured using a bead-based immunoassay and flow cytometry. Gene expression was quantified using qPCR. Data was analyzed by ANOVA and linear mixed model. RESULTS: Viability of the cells was dose- and time-dependent. A linear mixed statistical model showed that cobalt exposure induces increase in IL-6, CXCL8 and CCL2 production over time and whereas increase of IL-6 and a decrease of CCL2 was associated with increasing cobalt chloride concentrations. When comparing the cells incubated under high and low calcium conditions, the more differentiated cells in the high concentration were found to exert a stronger response in terms of IL-6 release. CONCLUSIONS: Our data suggest that cobalt chloride triggered an alarm system in HaCaT cells, and proinflammatory cytokines/chemokines were secreted in a dose- and time-dependent manner. When high and low calcium incubations were compared, the difference was seen only for IL-6. These findings indicate that the effect of cobalt chloride on cell toxicity occurs throughout the living epidermis.

Inflammatory and coagulatory markers and exposure to different size fractions of particle mass, number and surface area air concentrations in the Swedish hard metal industry, in particular to cobalt.

PURPOSE: To study the relationship between inhalation of airborne particles and cobalt in the Swedish hard metal industry and markers of inflammation and coagulation in blood. METHODS: Personal sampling of inhalable cobalt and dust were performed for subjects in two Swedish hard metal plants. Stationary measurements were used to study concentrations of inhalable, respirable, and total dust and cobalt, PM10 and PM2.5, the particle surface area and the particle number concentrations. The inflammatory markers CC16, TNF, IL-6, IL-8, IL-10, SAA and CRP, and the coagulatory markers FVIII, vWF, fibrinogen, PAI-1 and D-dimer were measured. A complete sampling was performed on the second or third day of a working week following a work-free weekend, and additional sampling was taken on the fourth or fifth day. The mixed model analysis was used, including covariates. RESULTS: The average air concentrations of inhalable dust and cobalt were 0.11 mg/m3 and 0.003 mg/m3, respectively. For some mass-based exposure measures of cobalt and total dust, statistically significant increased levels of FVIII, vWF and CC16 were found. CONCLUSIONS: The observed relationships between particle exposure and coagulatory biomarkers may indicate an increased risk of cardiovascular disease.

Activation of NLRP3 by uropathogenic Escherichia coli is associated with IL-1ß release and regulation of antimicrobial properties in human neutrophils.

The NLRP3 inflammasome and IL-1ß have recently been linked to the severity of uropathogenic Escherichia coli (UPEC)-mediated urinary tract infection (UTI). However, not much is known about the contribution of NLRP3 to the antimicrobial properties of neutrophils and the release of IL-1ß during UPEC infection. The purpose of this study was to elucidate the mechanisms behind UPEC-induced IL-1ß release from human neutrophils, and to investigate the contribution of the NLRP3 inflammasome in neutrophil-mediated inhibition of UPEC growth. We found that the UPEC strain CFT073 increased the expression of NLRP3 and increased caspase-1 activation and IL-1ß release from human neutrophils. The IL-1ß release was mediated by the NLRP3 inflammasome and by serine proteases in an NF-κB-and cathepsin B-dependent manner. The UPEC virulence factors α-hemolysin, type-1 fimbriae and p-fimbriae were all shown to contribute to UPEC mediated IL-1ß release from neutrophils. Furthermore, inhibition of caspase-1 and NLRP3 activation increased neutrophil ROS-production, phagocytosis and the ability of neutrophils to suppress UPEC growth. In conclusion, this study demonstrates that UPEC can induce NLRP3 and serine protease-dependent release of IL-1ß from human neutrophils and that NLRP3 and caspase-1 can regulate the antimicrobial activity of human neutrophils against UPEC.

Mechanisms of a Sustained Anti-inflammatory Drug Response in Alveolar Macrophages Unraveled with Mathematical Modeling.

Both initiation and suppression of inflammation are hallmarks of the immune response. If not balanced, the inflammation may cause extensive tissue damage, which is associated with common diseases, e.g., asthma and atherosclerosis. Anti-inflammatory drugs come with side effects that may be aggravated by high and fluctuating drug concentrations. To remedy this, an anti-inflammatory drug should have an appropriate pharmacokinetic half-life or better still, a sustained anti-inflammatory drug response. However, we still lack a quantitative mechanistic understanding of such sustained effects. Here, we study the anti-inflammatory response to a common glucocorticoid drug, dexamethasone. We find a sustained response 22 hours after drug removal. With hypothesis testing using mathematical modeling, we unravel the underlying mechanism-a slow release of dexamethasone from the receptor-drug complex. The developed model is in agreement with time-resolved training and testing data and is used to simulate hypothetical treatment schemes. This work opens up for a more knowledge-driven drug development to find sustained anti-inflammatory responses and fewer side effects.

Molecularly Distinct NLRP3 Inducers Mediate Diverse Ratios of Interleukin-1ß and Interleukin-18 from Human Monocytes.

Inflammasomes cleave and activate interleukin- (IL-) 1ß and IL-18 which have both shared and unique biological functions. IL-1ß is an important mediator of the acute phase response to infections and tissue damage, whereas IL-18 takes part in activation and tailoring of the adaptive immune response. While IL-1ß has served as the prototypic indicator of inflammasome activation, few studies have compared the potential differences in IL-1ß and IL-18 production during inflammasome activation. Since these cytokines partake in different immune pathways, the involvement of inflammasome activity in different conditions needs to be described beyond IL-1ß production alone. To address a potential heterogeneity in inflammasome functionality, ATP, chitosan, or silica oxide (SiO2) were used to induce NLRP3 inflammasome activation in THP-1 cells and the subsequent outcomes were quantified. Despite using doses of the inflammasome inducers yielding similar release of IL-1ß, SiO2-stimulated cells showed a lower concentration of released IL-18 compared to ATP and chitosan. Hence, the cells stimulated with SiO2 responded with a distinctly different IL-18 : IL-1ß ratio. The difference in the IL-18 : IL-1ß ratio for SiO2 was constant over different doses. While all downstream responses were strictly dependent on a functional NLRP3 inflammasome, the differences did not depend on the level of gene expression, caspase-1 activity, or pyroptosis. We suggest that the NLRP3 inflammasome response should be considered a dynamic process, which can be described by taking the ratio between IL-1ß and IL-18 into account and moving away from an on/off perspective of inflammasome activation.

Respiratory Health and Inflammatory Markers-Exposure to Cobalt in the Swedish Hard Metal Industry.

OBJECTIVE: To study the relationship between inhalable dust and cobalt, and respiratory symptoms, lung function, exhaled nitric oxide in expired air, and CC16 in the Swedish hard metal industry. METHODS: Personal sampling of inhalable dust and cobalt, and medical examination including blood sampling was performed for 72 workers. Exposure-response relationships were determined using logistic, linear, and mixed-model analysis. RESULTS: The average inhalable dust and cobalt concentrations were 0.079 and 0.0017 mg/m, respectively. Statistically significant increased serum levels of CC16 were determined when the high and low cumulative exposures for cobalt were compared. Nonsignificant exposure-response relationships were observed between cross-shift inhalable dust or cobalt exposures and asthma, nose dripping, and bronchitis. CONCLUSIONS: Our findings suggest an exposure-response relationship between inhalable cumulative cobalt exposure and CC16 levels in blood, which may reflect an injury or a reparation process in the lungs.