TNFalpha and MIP-2: role in particle-induced inflammation and regulation by oxidative stress

Pulmonary exposure to renewable diesel exhaust particles alters protein expression and toxicity profiles in bronchoalveolar lavage fluid and plasma of mice

Exposure to diesel exhaust is associated with increased risk of cardiovascular and lung disease. Substituting petroleum diesel with renewable diesel can alter emission properties but the potential health effects remain unclear. This study aimed to explore toxicity and underlying mechanisms of diesel exhaust from renewable fuels. Using proximity extension assay (Olink), 92 proteins linked to inflammation, cardiovascular function, and cancer were analyzed in bronchoalveolar lavage fluid (BALF) and plasma in mice 1 day after pulmonary exposure to exhaust particles at doses of 6, 18, and 54 µg/mouse. Particles were generated from combustion of renewable (rapeseed methyl ester, RME13, hydrogen-treated vegetable oil, HVO13; both at 13% O2 engine intake) and petroleum diesel (MK1 ultra-low-sulfur diesel at 13% and 17% O2 intake; DEP13 and DEP17). We identified positive dose-response relationships between exposure and proteins in BALF using linear models: 33 proteins for HVO13, 24 for DEP17, 22 for DEP13, and 12 for RME13 (p value < 0.05). In BALF, 11 proteins indicating cytokine signaling and inflammation (CCL2, CXCL1, CCL3L3, CSF2, IL1A, CCL20, TPP1, GDNF, LGMN, ITGB6, PDGFB) were common for all exposures. Several proteins in BALF (e.g., CCL2, CXCL1, CCL3L3, CSF2, IL1A) correlated (rs ≥ 0.5) with neutrophil cell count and DNA damage in BAL cells. Interestingly, plasma protein profiles were only affected by RME13 and, to lesser extent, by DEP13. Overall, we identified inflammation-related changes in the BALF as a common toxic mechanism for the combustion particles. Our protein-based approach enables sensitive detection of inflammatory protein changes across different matrices enhancing understanding of exhaust particle toxicity.

Influence of macrophages and neutrophilic granulocyte-like cells on crystalline silica-induced toxicity in human lung epithelial cells

In many industrial activities, workers may be exposed by inhalation to particles that are aerosolized, To predict the human health hazard of these materials, we propose to develop a co-culture model (macrophages, granulocytes, and alveolar epithelial cells) designed to be more representative of the inflammatory pulmonary response occurring in vivo. Phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1 cells were used as macrophages, All-trans retinoic acid (ATRA)-differentiated HL60 were used as granulocytes and A549 were used as epithelial alveolar type II cells. A crystalline silica sample DQ12 was used as a prototypical particle for its capabilities to induce DNA damage, inflammatory response, and oxidative stress in epithelial cells; its polyvinylpyridine-N-oxide (PVNO)-surface modified counterpart was also used as a negative particulate control. Cells in mono-, bi- or tri-culture were exposed to DQ12 or DQ12-PVNO for 24 h. DQ12 but not DQ12-PVNO induced a significant increase in DNA damage in A549 cells. The presence of differentiated THP-1 reduced the genotoxic effects of this crystalline silica sample. The exposure of A549 to DQ12 but not DQ12-PVNO induced a significant change in interleukin-8 (IL-8) protein levels which was exacerbated when differentiated THP-1, and HL-60, were added. In addition, while no production of TNFα was detected in the A549 monoculture, elevated levels of this cytokine were observed in the co-culture systems. This work shows that a cell culture model that takes into consideration the complexity of the pulmonary inflammatory response might be more dependable to study the toxicological properties of particles than "simple" monoculture models.

Sterile inflammation induced by respirable micro and nano polystyrene particles in the pathogenesis of pulmonary diseases

Sterile inflammation is involved in the lung pathogenesis induced by respirable particles, including micro- and nanoplastics. Their increasing amounts in the ambient and in indoor air pose a risk to human health. In two human cell lines (A549 and THP-1) we assessed the proinflammatory behavior of polystyrene nanoplastics (nPS) and microplastics (mPS) (Ø 0.1 and 1 μm). Reproducing environmental aging, in addition to virgin, the cells were exposed to oxidized nPS/mPS. To study the response of the monocytes to the inflammatory signal transmitted by the A549 through the release of soluble factors (e.g. alarmins and cytokines), THP-1 cells were also exposed to the supernatants of previously nPS/mPS-treated A549. After dynamic-light-scattering (DLS) analysis and protein measurements for the assessment of protein corona in nPS/mPS, real-time PCR and enzyme-linked-immunosorbent (ELISA) assays were performed in exposed cells. The pro-inflammatory effects of v- and ox-nPS/mPS were attested by the imbalance of the Bax/Bcl-2 ratio in A549, which was able to trigger the inflammatory cascade, inhibiting the immunologically silent apoptosis. The involvement of NFkB was confirmed by the overexpression of p65 after exposure to ox-nPS and v- and ox-mPS. The fast and higher levels of IL-1β, only in THP-1 cells, underlined the NLPR3 inflammasome activation.

Pulmonary toxicity assessment of polypropylene, polystyrene, and polyethylene microplastic fragments in mice

Polypropylene (PP), polystyrene (PS), and polyethylene (PE) plastics are commonly used in household items such as electronic housings, food packaging, bottles, bags, toys, and roofing membranes. The presence of inhalable microplastics in indoor air has become a topic of concern as many people spent extended periods of time indoors during the COVID-19 pandemic lockdown restrictions, however, the toxic effects on the respiratory system are not properly understood. We examined the toxicity of PP, PS, and PE microplastic fragments in the pulmonary system of C57BL/6 mice. For 14 days, mice were intratracheally instilled 5 mg/kg PP, PS, and PE daily. The number of inflammatory cells such as macrophages, neutrophils, and eosinophils in the bronchoalveolar lavage fluid (BALF) of PS-instilled mice was significantly higher than that in the vehicle control (VC). The levels of inflammatory cytokines and chemokines in BALF of PS-instilled mice increased compared to the VC. However, the inflammatory responses in PP- and PE-stimulated mice were not significantly different from those in the VC group. We observed elevated protein levels of toll-like receptor (TLR) 2 in the lung tissue of PP-instilled mice and TLR4 in the lung tissue of PS-instilled mice compared with those to the VC, while TLR1, TLR5, and TLR6 protein levels remained unchanged. Phosphorylation of nuclear factor kappa B (NF-κB) and IĸB-α increased significantly in PS-instilled mice compared with that in VC. Furthermore, Nucleotide‑binding oligomerization domain‑like receptor family pyrin domain‑containing 3 (NLRP3) inflammasome components including NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and Caspase-1 in the lung tissue of PS-instilled mice increased compared with that in the VC, but not in PP- and PE-instilled mice. These results suggest that PS microplastic fragment stimulation induces pulmonary inflammation due to NF-ĸB and NLRP3 inflammasome activation by the TLR4 pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-023-00224-x.

Biosensing Platform for the Detection of Biomarkers for ALI/ARDS in Bronchoalveolar Lavage Fluid of LPS Mice Model

Acute respiratory distress syndrome (ARDS) is a worldwide health concern. The pathophysiological features of ALI/ARDS include a pulmonary immunological response. The development of a rapid and low-cost biosensing platform for the detection of ARDS is urgently needed. In this study, we report the development of a paper-based multiplexed sensing platform to detect human NE, PR3 and MMP-2 proteases. Through monitoring the three proteases in infected mice after the intra-nasal administration of LPS, we showed that these proteases played an essential role in ALI/ARDS. The paper-based sensor utilized a colorimetric detection approach based on the cleavage of peptide-magnetic nanoparticle conjugates, which led to a change in the gold nanoparticle-modified paper sensor. The multiplexing of human NE, PR3 and MMP-2 proteases was tested and compared after 30 min, 2 h, 4 h and 24 h of LPS administration. The multiplexing platform of the three analytes led to relatively marked peptide cleavage occurring only after 30 min and 24 h. The results demonstrated that MMP-2, PR3 and human NE can provide a promising biosensing platform for ALI/ARDS in infected mice at different stages. MMP-2 was detected at all stages (30 min-24 h); however, the detection of human NE and PR3 can be useful for early- (30 min) and late-stage (24 h) detection of ALI/ARDS. Further studies are necessary to apply these potential diagnostic biosensing platforms to detect ARDS in patients.

Sources, chemical components, and toxicological responses of size segregated urban air PM samples in high air pollution season in Guangzhou, China

The sources, sizes, components, and toxicological responses of particulate matter (PM) have demonstrated remarkable spatiotemporal variability. However, associations between components, sources, and toxicological effects in different-sized PM remain unclear. The purposes of this study were to 1) determine the sources of PM chemical components, 2) investigate the associations between components and toxicology of PM from Guangzhou high air pollution season. We collected size-segregated PM samples (PM_10-2.5, PM_2.5-1, PM_1-0.2, PM_0.2) from December 2017 to March 2018 in Guangzhou. PM sources and components were analyzed. RAW264.7 mouse macrophages were treated with PM samples for 24 h followed by measurements of toxicological responses. The concentrations of PM_10-2.5 and PM_1-0.2 were relatively high in all samples. Water-soluble ions and PAHs were more abundant in smaller-diameter PM, while metallic elements were more enriched in larger-diameter PM. Traffic exhaust, soil dust, and biomass burning/petrochemical were the most important sources of PAHs, metals and ions, respectively. The main contributions to PM were soil dust, coal combustion, and biomass burning/petrochemical. Exposure to PM_10-2.5 induced the most significant reduction of cell mitochondrial activity, oxidative stress and inflammatory response, whereas DNA damage, an increase of Sub G1/G0 population, and impaired cell membrane integrity were most evident with PM_1-0.2 exposure. There were moderate or strong correlations between most single chemicals and almost all toxicological endpoints as well as between various toxicological outcomes. Our findings highlight those various size-segregated PM-induced toxicological effects in cells, and identify chemical components and sources of PM that play the key role in adverse intracellular responses. Although fine and ultrafine PM have attracted much attention, the inflammatory damage caused by coarse PM cannot be ignored.

Respiratory protective effects of Korean Red Ginseng in a mouse model of particulate matter 4-induced airway inflammation

Background

Air pollution has led to an increased exposure of all living organisms to fine dust. Therefore, research efforts are being made to devise preventive and therapeutic remedies against fine dust-induced chronic diseases.

Methods

Research of the respiratory protective effects of KRG extract in a particulate matter (PM; aerodynamic diameter of <4 μm) plus diesel exhaust particle (DEP) (PM4+D)-induced airway inflammation model. Nitric oxide production, expression of pro-inflammatory mediators and cytokines, and IRAK-1, TAK-1, and MAPK pathways were examined in PM4-stimulated MH-S cells. BALB/c mice exposed to PM4+D mixture by intranasal tracheal injection three times a day for 12 days at 3 day intervals and KRGE were administered orally for 12 days. Histological of lung and trachea, and immune cell subtype analyses were performed. Expression of pro-inflammatory mediators and cytokines in bronchoalveolar lavage fluid (BALF) and lung were measured. Immunohistofluorescence staining for IRAK-1 localization in lung were also evaluated.

Results

KRGE inhibited the production of nitric oxide, the expression of pro-inflammatory mediators and cytokines, and expression and phosphorylation of all downstream factors of NF-κB, including IRAK-1 and MAPK/AP1 pathway in PM4-stimulated MH-S cells. KRGE suppressed inflammatory cell infiltration and number of immune cells, histopathologic damage, and inflammatory symptoms in the BALF and lungs induced by PM4+D; these included increased alveolar wall thickness, accumulation of collagen fibers, and TNF-α, MIP2, CXCL-1, IL-1α, and IL-17 cytokine release. Moreover, PM4 participates induce alveolar macrophage death and interleukin-1α release by associating with IRAK-1 localization was also potently inhibited by KRGE in the lungs of PM4+D-induced airway inflammation model. KRGE suppresses airway inflammatory responses, including granulocyte infiltration into the airway, by regulating the expression of chemokines and inflammatory cytokines via inhibition of IRAK-1 and MAPK pathway. Conclusion: Our results indicate the potential of KRGE to serve as an effective therapeutic agent against airway inflammation and respiratory diseases.

Developments in Neuroprotection for HIV-Associated Neurocognitive Disorders (HAND)

PURPOSE OF REVIEW

Reducing the risk of HIV-associated neurocognitive disorders (HAND) is an elusive treatment goal for people living with HIV. Combination antiretroviral therapy (cART) has reduced the prevalence of HIV-associated dementia, but milder, disabling HAND is an unmet challenge. As newer cART regimens that more consistently suppress central nervous system (CNS) HIV replication are developed, the testing of adjunctive neuroprotective therapies must accelerate.

RECENT FINDINGS

Successes in modifying cART regimens for CNS efficacy (penetrance, chemokine receptor targeting) and delivery (nanoformulations) in pilot studies suggest that improving cART neuroprotection and reducing HAND risk is achievable. Additionally, drugs currently used in neuroinflammatory, neuropsychiatric, and metabolic disorders show promise as adjuncts to cART, likely by broadly targeting neuroinflammation, oxidative stress, aerobic metabolism, and/or neurotransmitter metabolism. Adjunctive cognitive brain therapy and aerobic exercise may provide additional efficacy. Adjunctive neuroprotective therapies, including available FDA-approved drugs, cognitive therapy, and aerobic exercise combined with improved cART offer plausible strategies for optimizing the prevention and treatment of HAND.

Laboratory investigation of pollutant emissions and PM2.5 toxicity of underground coal fires

Widespread underground coal fires (UCFs) release large amounts of pollutants, thus leading to air pollution and health impacts. However, this topic has not been widely investigated, especially regarding the potential health hazards. We quantified the pollutant emissions and analyzed the physicochemical properties of UCF PM_2.5 in a laboratory study of coal smoldering under a simulated UCF background. The emission factors of CO₂, CO, and PM_2.5 were 2489 ± 35, 122 ± 9, 12.90 ± 1.79 g/kg, respectively. UCF PM_2.5 are carbonaceous particles with varied morphology and complex composition, including heavy metals, silica and polycyclic aromatic hydrocarbons (PAHs). The main PAHs components were those with 2-4 rings. Benzoapyrene (BaP) and indeno[1,2, 3-cd]pyrene (IcdP) were important contributors to the carcinogenesis of these PAHs. We quantitatively evaluate the toxicity of inhaled UCF PM_2.5 using a nasal inhalation exposure system. The target organs of UCF PM_2.5 are lungs, liver, and kidneys. UCF PM_2.5 presented an enriched chemical composition and induced inflammation and oxidative stress, which together mediated multiple organ injury. Long-term PM_2.5 metabolism is the main cause of persistent toxicity, which might lead to long-term chronic diseases. Therefore, local authorities should recognize the importance and effects of UCF emissions, especially PM_2.5, to establish control and mitigation measures.

Investigations on Cellular Uptake Mechanisms and Immunogenicity Profile of Novel Bio-Hybrid Nanovesicles

In drug delivery, the development of nanovesicles that combine both synthetic and cellular components provides added biocompatibility and targeting specificity in comparison to conventional synthetic carriers such as liposomes. Produced through the fusion of U937 monocytes' membranes and synthetic lipids, our nano-cell vesicle technology systems (nCVTs) showed promising results as targeted cancer treatment. However, no investigation has been conducted yet on the immunogenic profile and the uptake mechanisms of nCVTs. Hence, this study was aimed at exploring the potential cytotoxicity and immune cells' activation by nCVTs, as well as the routes through which cells internalize these biohybrid systems. The endocytic pathways were selectively inhibited to establish if the presence of cellular components in nCVTs affected the internalization route in comparison to both liposomes (made up of synthetic lipids only) and nano-cellular membranes (made up of biological material only). As a result, nCVTs showed an 8-to-40-fold higher cellular internalization than liposomes within the first hour, mainly through receptor-mediated processes (i.e., clathrin- and caveolae-mediated endocytosis), and low immunostimulatory potential (as indicated by the level of IL-1α, IL-6, and TNF-α cytokines) both in vitro and in vivo. These data confirmed that nCVTs preserved surface cues from their parent U937 cells and can be rationally engineered to incorporate ligands that enhance the selective uptake and delivery toward target cells and tissues.

Assessing the impact of gestational age of donors on the efficacy of amniotic epithelial cell-derived extracellular vesicles in experimental bronchopulmonary dysplasia

Background and rationale

Extracellular vesicles (EVs) are a potential cell-free regenerative medicine. Human amniotic epithelial cells (hAECs) are a viable source of cell therapy for diseases like bronchopulmonary dysplasia (BPD). However, little is known about the impact of gestational age of the donor on the quality of hAEC-derived EVs.

Aims

To determine the impact of gestational age on hAEC-derived EVs in experimental BPD.

Results

Term hAEC-derived EVs displayed a significantly higher density of surface epitopes (CD142 and CD133) and induced greater macrophage phagocytosis compared to preterm hAEC-EVs. However, T cell proliferation was more significantly suppressed by preterm hAEC-EVs. Using a model of experimental BPD, we observed that term but not preterm hAEC-EVs improved tissue-to-airspace ratio and septal crest density. While both term and preterm hAEC-EVs reduced the levels of inflammatory cytokines on postnatal day 7, the improvement in lung injury was associated with increased type II alveolar cells which was only observed in term hAEC-EV treatment group. Furthermore, only neonatal term hAEC-EVs reduced airway hyper-responsiveness, mitigated pulmonary hypertension and protected against right ventricular hypertrophy at 6 weeks of age.

Conclusion

Term hAEC-EVs, but not preterm hAEC-EVs, have therapeutic efficacy in a mouse model of BPD-like lung injury. Therefore, the impact of donor criteria should be considered when applying perinatal cells-derived EV therapy for clinical use.

Inhibitory effects of modified gamgil-tang in a particulate matter-induced lung injury mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

The modified gamgil-tang (GGX) is a mixture of four herbal medicine including Platycodi Radix, Glycyrrhizae Radix, Lonicerae Flos and Mori Radicis Cortex which has been traditionally used to treat lung and airway diseases to relieve symptoms like sore throat, cough, and sputum in Korea. Its major component chlorogenic acid had been reported to have antioxidant, antibacterial, hepatoprotective, cardioprotective, anti-inflammatory, antiviral, and anti-microbial activity.

AIM OF THE STUDY

To identify the inhibitory effect of GGX in a particulate matter (PM) induced lung injury mouse model.

MATERIALS AND METHODS

We evaluated NO production, the release of TNF-α and IFN-γ in PM-induced MH-S cells, and the number of neutrophils, immune cell subtypes, and the secretion of TNF-α, IL-17, CXCL-1, MIP-2 in the PM-stimulated mouse model to assess the inhibitory effect of GGX against PM. In addition, as exposure to PM increases respiratory symptoms, typically cough and sputum, we attempted to evaluate the antitussive and expectorant activities of GGX.

RESULTS

Our study provided evidence that GGX has inhibitory effects in PM-induced lung injury by inhibiting the increase in neutrophil and inflammatory mediators, deactivating T cells, and ameliorating lung tissue damage. Notably, GGX reduced PM-induced neutrophilic inflammation by attenuating the number of neutrophils and regulating the secretion of neutrophil-related cytokines and chemokines, such as TNF-α, IL-17, MIP2, and CXCL-1. In addition, GGX demonstrated an antitussive activity by significantly reducing citric acid-induced cough frequency and delaying the latent period and expectorant activities by the increased phenol red secretion compared to the control group.

CONCLUSIONS

GGX is expected to be an effective herbal remedy to prevent PM-induced respiratory disease.

Long non-coding RNA LINC01194 promotes the inflammatory response and apoptosis of LPS-treated MLE 12 cells through the miR-203a-3p /MIP-2 axis

Acute lung injury (ALI) induced by bacteria LPS is characterized by the upregulation of the apoptosis rate of tissue cells and aggravation of inflammatory response. Although many studies have focused on the pathogenesis of this disease, its mechanism remains unknown. This study examined the regulatory role of long non-coding RNA (lncRNA) LINC01194 in the progression of ALI through various bioinformatics analyses and experimental work, including ELISA assay, dual-luciferase reporter assay, biotinylated RNA pull-down assay, and western blot analysis. The result showed that the LINC01194 was overexpressed in the ALI-induced mice model. We observed a significant upregulation of LINC01194 in LPS-treated Mouse lung epithelial type II cells (MLE-12 cells) after 24 hrs of induction. Bioinformatics analysis, Elisa assay, qRT-PCR analysis, Biotinylated RNA pull-down assay, apoptosis test, and western blot analysis demonstrated that the LINC01194 could act as a miR-203a-3p sponge to activate the inflammatory response in LPS-induced ALI model through post-transcriptional upregulation of MIP-2. We showed that LINC01194 regulates the inflammatory response and apoptosis of LPS-induced mice and MLE-12 cells via the miR-203a-3p/MIP-2 axis. LINC01194 could be a potential biomarker for early diagnosis and the treatment of ALI.

An in vitro assessment of the toxicity of two-dimensional synthetic and natural layered silicates

Natural Layered Silicates (NLS) and Synthetic Layered Silicates (SLS) are a diverse group of clay minerals that have attracted great interest in various branches of industry. However, despite growing demand for this class of material, their impact on human health has not been fully investigated. Therefore, the aim of this study was to evaluate and compare the potential toxic effects of a wide range of commercially available SLS and NLS of varying physicochemical properties (lithium (Li) or fluoride (F) content and size). Mouse BALB/c monocyte macrophage (J774A.1) and human monocyte-derived macrophages (MDMs) were chosen as in vitro models of alveolar macrophages. Montmorillonite, hectorite, Medium (med) F/High Li and Low F/Med Li particles, were cytotoxic to cells and induced potent pro-inflammatory responses. The remaining particles (No F/Very (V)Low Li, No F/Med Li, No F/Low Li, High F/Med Li and High F/Med Li washed) were non- to relatively low- cytotoxic and inflammogenic, in both type of cells. In an acellular condition none of the tested samples increased reactive oxygen species (ROS), while ROS generation was observed following exposure to sublethal concentrations of Med F/High Li, Low F/Med Li, montmorillonite and hectorite samples, in J774A.1 cells. Based on the results obtained in this study the toxic potency of tested samples was not associated with lithium or fluoride content, but appeared to be dependent on particle size, with the platelets of larger dimension and lower surface area being more potent than the smaller platelet particles with higher surface area. In addition, the increased bioactivity of Med F/High Li and Low F/Med Li was associated with endotoxin contamination. Obtained results demonstrated that layered silicate materials have different toxicological profiles and suggest that toxicological properties of a specific layered silicate should be investigated on an individual basis.

Nicaraven prevents the fast growth of inflamed tumors by an anti-inflammatory mechanism

Inflammatory microenvironment is known to accelerate the progression of malignant tumors. We investigated the possible anti-inflammatory effect of nicaraven on slowing tumor growth. Tumor-bearing mice randomly received nicaraven injection (50 mg/kg daily, i.p, n = 8) or placebo treatment (n = 8) for 10 days, and then sacrificed for evaluations. Nicaraven administration effectively inhibited the fast growth of tumor, as a large tumor (> 1.0 g) developed finally in three of the eight mice received placebo treatment. Cytokines/chemokines array indicated that nicaraven reduced the levels of CXCL10 and SDF-1 in the tumor as well as the levels of IL-2 and MIP-2 in serum. Immunofluorescence staining showed that nicaraven significantly reduced the recruitment of macrophages and neutrophils in the tumor. Interestingly, western blot indicated that the expression of CD86, CD206, and NIMP-R14 was especially enhanced in the three large-size tumors, suggesting the potential role of nicaraven in preventing the hyper-inflammatory tumor microenvironment. Moreover, the expression of PARP-1 was downregulated, but the expression of phospho-p38 MAPK, phospho-MKK-3/6, and phospho-MSK-1 was upregulated in the large-size tumors, suggesting the involvement of p38 MAPK pathway in the anti-inflammatory effect of nicaraven. Taken together, our study suggests that nicaraven may effectively prevent the fast growth of inflamed tumors by an anti-inflammatory mechanism.

Alteration in antioxidant status in slow and fast alleles of EPHX1 gene polymorphisms among wood workers

Occupational wood dust exposure may be associated with various health effects, especially in wood industry. These effects may be due to inducing oxidative stress which is related to inflammations. Biochemical assessment of antioxidant enzyme activities illustrated role of oxidative stress (OS) on its depletion. Super oxide dismutase, glutathione peroxidase (GPx) and catalase (CAT) were analyzed in 50 exposed workers and 50 control subjects. Also, macrophage inflammatory protein-2 was assessed among these workers as it was produced upon dust exposure. Microsomal epoxide hydrolase (EPHX1) enzyme shared in the protective mechanism against wood dust oxidative stress. It plays a dual role in the metabolism of environmental pollutants, detoxification, and bioactivation. Gene polymorphisms of EPHX1 may be associated with variations in enzyme activity. Polymorphisms in exons 3 and 4 have resulted in either decreased (slow conjugating allele) or increased (fast conjugating allele) activity in vitro. We aimed to evaluate the associations between EPHX1 polymorphisms and change in antioxidant status (SOD, CAT, and GPx) among wood dust exposed workers. EPHX1 genotyping in exon 3 and exon 4 polymorphisms was carried out by PCR-RFLP. Our result shows a significant reduction in enzymatic antioxidants (SOD, CAT, and GPx) levels with significant rise in MIP-2 levels in worker group. Also, there are significant variations in SOD, CAT, and GPx levels as well as in MIP-2 in different genotypes of EPHX polymorphisms in exon 3 or 4 (specially in Hist-Hist genotypes in both exons). We can conclude an alteration in antioxidant status in both slow and fast allele of EPHX gene polymorphisms with release of MIP-2 protein in wood workers.

An Integrated Approach to Testing and Assessment to Support Grouping and Read-Across of Nanomaterials After Inhalation Exposure

Introduction: Here, we describe the generation of hypotheses for grouping nanoforms (NFs) after inhalation exposure and the tailored Integrated Approaches to Testing and Assessment (IATA) with which each specific hypothesis can be tested. This is part of a state-of-the-art framework to support the hypothesis-driven grouping and read-across of NFs, as developed by the EU-funded Horizon 2020 project GRACIOUS.

Development of Grouping Hypotheses and IATA: Respirable NFs, depending on their physicochemical properties, may dissolve either in lung lining fluid or in acidic lysosomal fluid after uptake by cells. Alternatively, NFs may also persist in particulate form. Dissolution in the lung is, therefore, a decisive factor for the toxicokinetics of NFs. This has led to the development of four hypotheses, broadly grouping NFs as instantaneous, quickly, gradually, and very slowly dissolving NFs. For instantaneously dissolving NFs, hazard information can be derived by read-across from the ions. For quickly dissolving particles, as accumulation of particles is not expected, ion toxicity will drive the toxic profile. However, the particle aspect influences the location of the ion release. For gradually dissolving and very slowly dissolving NFs, particle-driven toxicity is of concern. These NFs may be grouped by their reactivity and inflammation potency. The hypotheses are substantiated by a tailored IATA, which describes the minimum information and laboratory assessments of NFs under investigation required to justify grouping.

Conclusion: The GRACIOUS hypotheses and tailored IATA for respiratory toxicity of inhaled NFs can be used to support decision making regarding Safe(r)-by-Design product development or adoption of precautionary measures to mitigate potential risks. It can also be used to support read-across of adverse effects such as pulmonary inflammation and subsequent downstream effects such as lung fibrosis and lung tumor formation after long-term exposure.

The effect of environmental diesel exhaust pollution on SARS-CoV-2 infection: The mechanism of pulmonary ground glass opacity

Diesel exhaust particles (DEP) are the major components of atmospheric particulate matter (PM) and chronic exposure is recognized to enhance respiratory system complications. Although the spread of SARS-CoV-2 was found to be associated with the PMs, the mechanism by which exposure to DEP increases the risk of SARS-CoV-2 infection is still under discussion. However, diesel fine PM (dPM) elevate the probability of SARS-CoV-2 infection, as it coincides with the increase in the number of ACE2 receptors. Expression of ACE2 and its colocalized activator, transmembrane protease serine 2 (TMPRSS2) facilitate the entry of SARS-CoV-2 into the alveolar epithelial cells exposed to dPM. Thus, the coexistence of PM and SARS-CoV-2 in the environment augments inflammation and exacerbates lung damage. Increased TGF-β1 expression due to DEP accompanies the proliferation of the extracellular matrix. In this case, "multifocal ground-glass opacity" (GGO) in a CT scan is an indication of a cytokine storm and severe pneumonia in COVID-19.

Mechanistic Insights into the Role of Iron, Copper, and Carbonaceous Component on the Oxidative Potential of Ultrafine Particulate Matter

Transition metals play a key role in the pathogenic potential of urban particulate matter (PM). However, air quality regulations include exposure limits only for metals having a known toxic potential like Pb, As, Cd, and Ni, neglecting other transition metals like Fe and Cu. Fe and Cu are mainly found in the water-soluble fraction of PM. However, a fraction of the ions may persist strongly bound to the particles, thus potentially acting as surface reactive sites. The contribution of surface ions to the oxidative potential (OP) of PM is likely different from that of free ions since the redox activity of metals is modulated by their local chemical environment. The aim of this study was to investigate how Fe and Cu bound to carbonaceous particles affect the OP and associated toxicity of PM toward epithelial cells and macrophages. Carbonaceous nanoparticles (CNPs) having well-defined size were loaded with controlled amounts of Cu and Fe. The effect of Cu and Fe on the OP of CNPs was evaluated by electronic paramagnetic resonance (EPR) spectroscopy associated with the spin-trapping technique and correlated with the ability to induce cytotoxicity (LDH, WST-1), oxidative stress (Nrf2 translocation), and DNA damage (comet assay) on lung macrophages (NR8383) and/or epithelial cells (RLE-6TN). The release of pro-inflammatory cytokines (TNF-α, MCP-1, and CXCL2) by macrophages and epithelial cells was also investigated. The results indicate a major contribution of surface Cu to the surface reactivity of CNPs, while Fe has a minor role. At the same time, Cu increases the cytotoxicity of CNPs and their ability to induce oxidative stress and DNA damage. In contrast, surface Fe increases the release of pro-inflammatory cytokines by macrophages. Overall, these results confirm the role of Cu and Fe in PM toxicity and suggest that the total metals content in PM might be a better indicator of pathogenicity than water-soluble metals.

Effects of Betulinic Acid Derivative on Lung Inflammation in a Mouse Model of Chronic Obstructive Pulmonary Disease Induced by Particulate Matter 2.5

BACKGROUND Chronic obstructive pulmonary disease (COPD) is mainly induced by the increased content of particulate matter 2.5 (PM2.5) in the atmosphere. This study aimed to evaluate the effects of betulinic acid derivative on lung inflammation in a mouse model of chronic obstructive pulmonary disease induced by particulate matter 2.5. MATERIAL AND METHODS The mice were given a PM2.5 (25 μl) suspension for 7 days by the intranasal route to establish a COPD model. The content of TNF-alpha and IL-6 in the BALF samples was measured by commercially available ELISA kits. RESULTS The PM2.5-induced higher LDH and ACP levels were significantly alleviated in mouse lung tissues by treatment with betulinic acid derivative. Treatment with betulinic acid derivative also suppressed PM2.5-induced increase in AKP and ALB levels in mouse lung tissues. Betulinic acid derivative reversed PM2.5-mediated suppression of SOD activity and elevation of NOS level in mouse BALF. Moreover, the PM2.5-induced excessive NO and MDA levels in mouse BALF were significantly reduced (P.

Hypericum ascyron L. extract reduces particulate matter-induced airway inflammation in mice

The consequences of increased industrialization increased the risk of asthma and breathing difficulties due to increased particulate matter in the air. We aim to investigate the therapeutic properties of Hypericum ascyron L. extract (HAE) in airway inflammation and unravel its mechanism of action. We conducted nitric oxide and cell viability assay, real-time PCR and western blot analyses along with in vitro studies. in vivo studies include a model of coal fly ash and diesel exhaust particle (CFD)-induced airway inflammation in mice. HAE reduced coal fly ash (CFA)-induced nitric oxide secretion without exhibiting cytotoxicity in MH-S cells. HAE also reduced the mRNA expression of pro-inflammatory cytokines and reduced the expression of proteins in the NFκB and MAPK pathways. In a mice model of CFD-induced airway inflammation, HAE effectively reduced neutrophil infiltration in bronchoalveolar lavage fluid (BALF) and increased the amount of T cells in the BALF, lungs, and blood while reducing all other immune cell subtypes to reduce airway inflammatory response. CXCL-1, IL-17, MIP-2, and TNF-α expression in the BALF were also reduced. HAE effectively reduced MIP-2 and TNF-α mRNA expression in the lung tissue of mice. In a nutshell, HAE is effective in preventing airway inflammation induced by CFA in MH-S cells, as well as inflammation induced by CFD in mice.

Microglial Response to Aspergillus flavus and Candida albicans: Implications in Endophthalmitis

Aspergillus flavus is the most common etiology of fungal endophthalmitis in India, while Candida albicans is the causative agent in the West. In this study, we determined the role of microglial cells in evoking an inflammatory response following an infection with A. flavus and C. albicans strains isolated from patients with endophthalmitis. Microglia (CHME-3) cells were infected with A. flavus and C. albicans and the expression of Toll-Like Receptors (TLRs), cytokines and Matrix metalloproteinases (MMPs) were assessed at various time intervals. A. flavus infected cells induced higher expressions of TLR-1, -2, -5, -6, -7 and -9 and cytokines such as IL-1α, IL-6, IL-8, IL-10 and IL-17. In contrast, C. albicans infected microglia induced only TLR-2 along with the downregulation of IL-10 and IL-17. The expression of MMP-9 (Matrix metalloproteinase-9) was however upregulated in both A. flavus and C. albicans infected microglia. These results indicate that microglial cells have the ability to incite an innate response towards endophthalmitis causing fungal pathogens via TLRs and inflammatory mediators. Moreover, our study highlights the differential responses of microglia towards yeast vs. filamentous fungi.

Effects of a herbal formulation, KGC3P, and its individual component, nepetin, on coal fly dust-induced airway inflammation

Coal fly dust (CFD)-induced asthma model is used as an ambient particulate matter model of serious pulmonary damage. We aimed to evaluate the effects of a combination of ginseng and Salvia plebeia R. Br extract (KGC-03-PS; KG3P) and its individual components (hispidulin, nepetin and rosmarinic acid) in a CFD-induced mouse model of airway inflammation (asthma). We also evaluated signal transduction by KG3P and its individual components in the alveolar macrophage cell line, MH-S cells. In vitro, KG3P and its individual components inhibited nitric oxide production and expression of pro-inflammatory mediators and cytokines (iNOS, COX-2, IL-1β, IL-6 and TNF-α) through the NF-κB and MAPK pathways in coal fly ash (CFA)-induced inflammation in MH-S cells. Moreover, in the CFD-induced asthma model in mice, KG3P and its predominant individual component, nepetin, inhibited Asymmetric Dimethyl arginine (ADMA) and Symmetric Dimethyl arginine (SDMA) in serum, and decreased the histopathologic score in the lungs. A significant reduction in the neutrophils and immune cells in BALF and lung tissue was demonstrated, with significant reduction in the expression of the pro-inflammatory cytokines. Finally, IRAK-1 localization was also potently inhibited by KG3P and nepetin. Thus, KG3P extract can be considered as a potent candidate for amelioration of airway inflammation.

Protective Effect of GHX02 Extract on Particulate Matter-Induced Lung Injury

Industrial development, along with the rapid growth of the economy, has greatly improved the quality of life in humans. Moreover, advancements in medical technology have increased life expectancy. Small particles increase airway inflammation when they penetrate the alveoli. We observed that GHX02 decreased the frequency and delayed the onset time of citric acid-induced coughing in guinea pigs. A phenol red secretion assay indicated that the GHX02 extract exhibits potent expectorant activity. The GHX02 extract also greatly reduced leukocyte levels. Our results indicate that GHX02 inhibits airway inflammation, reduces sputum production, and relieves cough. The GHX02 extract suppressed histamine release from mast cells resulting from compound 48/80-induced degranulation. The extract exhibited antimicrobial activity against Streptococcus pneumoniae and significantly inhibited the formation of LTC4. At high concentrations, the GHX02 extract suppressed the formation of PGE2 (prostaglandin E2). Interleukin (IL)-4 and IL-13 levels decreased with an increasing dosage of GHX02. Oral administration of the GHX02 extract suppressed PM₁₀D-induced inflammatory symptoms in the lung, including increased alveolar wall thickness, accumulation of collagen fibers, and cytokine release. Treatment with the GHX02 extract also resulted in lower levels of inflammatory cells, in bronchoalveolar lavage fluid and lung tissue. Our results indicate that GHX02 may be a useful therapeutic agent for treatment of respiratory diseases.

Preventive effect of ursolic acid derivative on particulate matter 2.5-induced chronic obstructive pulmonary disease involves suppression of lung inflammation

Respiratory diseases like chronic obstructive pulmonary disease (COPD) are associated with the presence of particulate matter 2.5 (PM2.5) in the air. In the present study, the effect of synthesized ursolic acid derivatives on mice model of PM2.5-induced COPD was investigated in vivo. The mice model of COPD was established by the administration of 25 μL of PM2.5 suspension through intranasal route daily for 1 week. The levels of oxidative stress markers and inflammatory cytokines like tumor necrosis factors-α and interleukin-6 in the mice bronchoalveolar fluids increased markedly on administration with PM2.5. However, treatment with ursolic acid derivative caused a significant suppression in PM2.5-induced increase in oxidative stress markers and inflammatory cytokines in dose-dependent manner. Hematoxylin and eosin staining showed excessive inflammatory cell infiltration in pulmonary tissues in mice with COPD. The inflammatory cell infiltration was inhibited on treatment of the mice with ursolic acid derivative. The ursolic acid derivative treatment increased level of superoxide dismutase in mice with COPD. The lung injury induced by PM2.5 in mice was also prevented on treatment with ursolic acid derivative. Thus, ursolic acid derivative inhibits pulmonary tissues damage in mice through suppression of inflammatory cytokine and oxidative enzymes. Therefore, ursolic acid derivative can be of therapeutic importance for treatment of PM2.5-induced COPD.

Time-course transcriptomic alterations reflect the pathophysiology of polyhexamethylene guanidine phosphate-induced lung injury in rats

Objective: Humidifier-disinfectant-induced lung injury is a new syndrome associated with a high mortality rate and characterized by severe hypersensitivity pneumonitis, acute interstitial pneumonia, or acute respiratory distress syndrome. Polyhexamethylene guanidine phosphate (PHMG-P), a guanidine-based antimicrobial agent, is a major component associated with severe lung injury. In-depth studies are needed to determine how PHMG-P affects pathogenesis at the molecular level. Therefore, in this study, we analyzed short-term (4 weeks) and long-term (10 weeks) PHMG-P-exposure-specific gene-expression patterns in rats to improve our understanding of time-dependent changes in fibrosis.Materials and methods: Gene-expression profiles were analyzed in rat lung tissues using DNA microarrays and bioinformatics tools.Results: Clustering analysis of gene-expression data showed different gene-alteration patterns in the short- and long-term exposure groups and higher sensitivity to gene-expression changes in the long-term exposure group than in the short-term exposure group. Supervised analysis revealed 34 short-term and 335 long-term exposure-specific genes, and functional analysis revealed that short-term exposure-specific genes were involved in PHMG-P-induced initial inflammatory responses, whereas long-term exposure-specific genes were involved in PHMG-P-related induction of chronic lung fibrosis.Conclusion: The results of transcriptomic analysis were consistent with lung histopathology results. These findings indicated that exposure-time-specific changes in gene expression closely reflected time-dependent pathological changes in PHMG-P-induced lung injury.

Assessing the bioactivity of crystalline silica in heated high-temperature insulation wools

High-Temperature Insulation Wools (HTIW), such as alumino silicate wools (Refractory Ceramic Fibers) and Alkaline Earth Silicate wools, are used in high-temperature industries for thermal insulation. These materials have an amorphous glass-like structure. In some applications, exposure to high temperatures causes devitrification resulting in the formation of crystalline species including crystalline silica. The formation of this potentially carcinogenic material raises safety concerns regarding after-use handling and disposal. This study aims to determine whether cristobalite formed in HTIW is bioactive in vitro. Mouse macrophage (J774A.1) and human alveolar epithelial (A549) cell lines were exposed to pristine HTIW of different compositions, and corresponding heat-treated samples. Cell death, cytokine release, and reactive oxygen species (ROS) formation were assessed in both cell types. Cell responses to aluminum lactate-coated fibers were assessed to determine if responses were caused by crystalline silica. DQ12 α-quartz was used as positive control, and TiO₂ as negative control. HTIW did not induce cell death or intracellular ROS, and their ability to induce pro-inflammatory mediator release was low. In contrast, DQ12 induced cytotoxicity, a strong pro-inflammatory response and ROS generation. The modest pro-inflammatory mediator responses of HTIW did not always coincide with the formation of cristobalite in heated fibers; therefore, we cannot confirm that devitrification of HTIW results in bioactive cristobalite in vitro. In conclusion, the biological responses to HTIW observed were not attributable to a single physicochemical characteristic; instead, a combination of physicochemical characteristics (cristobalite content, fiber chemistry, dimensions and material solubility) appear to contribute to induction of cellular responses.

Exposure to ambient particulate matter induces oxidative stress in lung and aorta in a size- and time-dependent manner in rats

Exposure to particulate matter (PM) has been implicated in oxidative stress (OxS) and inflammation as underlying mechanisms of lung damage and cardiovascular alterations. PM is a chemical mixture that can be subdivided according to their aerodynamic size into coarse (CP), fine (FP), and ultrafine (UFP) particulates. We investigated, in a rat model, the induction of OxS (protein oxidation and antioxidant response), carcinogen-DNA adduct formation, and inflammatory mediators in lung in response to different airborne particulate fractions, CP, FP, and UFP, after an acute and subchronic exposure. In addition, OxS was evaluated in the aorta to assess the effects beyond the lungs. Exposure to CP, FP, and UFP induced time- and size-dependent lung protein oxidation and DNA adduct formation. After acute and subchronic exposure, nuclear factor erythroid-2 (Nrf2) activation was observed in the lung, by electrophoretic mobility shift assay, and the induction of mRNA antioxidant enzymes in the FP and UFP groups, but not in the CP. Cytokine concentration of interleukin 1β, interleukin 6, and macrophage inflammatory protein-2 was significantly increased in bronchoalveolar lavage fluid after acute exposure to FP and UFP. Activation of Nrf2 and expression of mRNA antioxidant enzymes were observed only after the subchronic exposure to FP and UFP in the aorta. Our results indicate that FP and UFP were mainly accountable for the oxidant toxic effects in the lung; OxS is spread from the lung to the cardiovascular system. We conclude that the biological mechanisms associated with transient OxS and inflammation are particle size and time-dependent exposure resulting in acute lung injury, which later reaches the vascular system.

Pulmonary Administration of Microparticulate Antisense Oligonucleotide (ASO) for the Treatment of Lung Inflammation

Targeted delivery to the lung for controlling lung inflammation is an area that we have explored in this study. The purpose was to use microparticles containing an antisense oligonucleotide (ASO) to NF-κB to inhibit the production of proinflammatory cytokines. Microparticles were prepared using the B-290 Buchi Spray Dryer using albumin as the microparticle matrix. Physicochemical characterization of the microparticles showed the size ranged from 2 to 5 μm, the charge was - 38.4 mV, and they had a sustained release profile over 72 h. Uptake of FITC-labeled ASO-loaded microparticles versus FITC-labeled ASO solution by RAW264.7 murine macrophage cells was 5-10-fold higher. After pulmonary delivery of microparticles to Sprague-Dawley rats, the microparticles were uniformly distributed throughout the lung and were retained in the lungs until 48 h. Serum cytokine (TNF-α and IL-1β) levels of rats after induction of lung inflammation by lipopolysaccharide were measured until 72 h. Animals receiving ASO-loaded microparticles were successful in significantly controlling lung inflammation during this period as compared to animals receiving no treatment. This study was successful in proving that microparticulate ASO therapy was capable of controlling lung inflammation.

LASSBio-897 Reduces Lung Injury Induced by Silica Particles in Mice: Potential Interaction with the A2A Receptor

Silicosis is a lethal fibro-granulomatous pulmonary disease highly prevalent in developing countries, for which no proper therapy is available. Among a small series of N-acylhydrazones, the safrole-derived compound LASSBio-897 (3-thienylidene-3, 4-methylenedioxybenzoylhydrazide) raised interest due to its ability to bind to the adenosine A_2A receptor. Here, we evaluated the anti-inflammatory and anti-fibrotic potential of LASSBio-897, exploring translation to a mouse model of silicosis and the A_2A receptor as a site of action. Pulmonary mechanics, inflammatory, and fibrotic changes were assessed 28 days after intranasal instillation of silica particles in Swiss–Webster mice. Glosensor cAMP HEK293G cells, CHO cells stably expressing human adenosine receptors and ligand binding assay were used to evaluate the pharmacological properties of LASSBio-897 in vitro. Molecular docking studies of LASSBio-897 were performed using the genetic algorithm software GOLD 5.2. We found that the interventional treatment with the A_2A receptor agonist CGS 21680 reversed silica particle-induced airway hyper-reactivity as revealed by increased responses of airway resistance and lung elastance following aerosolized methacholine. LASSBio-897 (2 and 5 mg/kg, oral) similarly reversed pivotal lung pathological features of silicosis in this model, reducing levels of airway resistance and lung elastance, granuloma formation and collagen deposition. In competition assays, LASSBio-897 decreased the binding of the selective A_2A receptor agonist [³H]-CGS21680 (IC₅₀ = 9.3 μM). LASSBio-897 (50 μM) induced modest cAMP production in HEK293G cells, but it clearly synergized the cAMP production by adenosine in a mechanism sensitive to the A_2A antagonist SCH 58261. This synergism was also seen in CHO cells expressing the A_2A, but not those expressing A_2B, A₁ or A₃ receptors. Based on the evidence that LASSBio-897 binds to A_2A receptor, molecular docking studies were performed using the A_2A receptor crystal structure and revealed possible binding modes of LASSBio-897 at the orthosteric and allosteric sites. These findings highlight LASSBio-897 as a lead compound in drug development for silicosis, emphasizing the role of the A_2A receptor as its putative site of action.

Therapeutic effects of stemonine on particulate matter 2.5-induced chronic obstructive pulmonary disease in mice

Particulate matter 2.5 (PM_2.5) is a growing concern worldwide due to its association with respiratory diseases, including chronic obstructive pulmonary disease (COPD). Stemonine, a traditional Chinese herb, has been demonstrated to exhibit anti-inflammatory and antioxidant properties, making it a potential drug for the treatment of respiratory diseases. The therapeutic effects of stemonine on mice with PM_2.5-induced COPD were investigated in the present study. Kunming mice were randomly divided into the following five groups (n=10/group): Control, model, low-dose stemonine, moderate-dose stemonine and high-dose stemonine. The model mice received an intranasal instillation of PM_2.5 suspension (40 mg/kg). The levels of specific enzymes, markers of oxidative stress, and the inflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6 were measured in the bronchoalveolar lavage fluid of the mice using ELISA kits. Hematoxylin and eosin staining was performed to determine inflammatory changes to the lung tissue. It was demonstrated that stemonine could significantly alleviate lung injury by decreasing the levels of enzymes and cytokines associated with inflammation and oxidative stress in a dose-dependent manner. In addition, stemonine dose-dependently increased the amount of superoxide dismutase. These results suggest that stemonine reduces lung inflammation in mice with PM_2.5-induced COPD, providing a novel approach for the treatment of PM_2.5-induced respiratory diseases.

TcpC secreting uropathogenic E. coli promoted kidney cells to secrete MIP-2 via p38 MAPK pathway

Pyelonephritis is an infection of the upper urinary tract with characteristic histological change to neutrophil infiltration in the kidney. The majority of pyelonephritis is caused by uropathogenic Escherichia (E.) coli (UPEC) bearing distinct virulence factors. Toll/interleukin‑1 receptor domain‑containing protein C (TcpC) encoded by E. coli is an important virulence factor in the majority of strains of UPEC and inhibits macrophage‑mediated innate immunity, which serves an essential role in the pathogenesis of pyelonephritis. In the present study, it was demonstrated that TcpC induced kidney cells to produce macrophage inflammatory protein‑2 (MIP‑2; also known as C‑X‑C motif chemokine 2). MIP‑2 concentration in kidney homogenates from TcpC‑secreting UPEC CFT073 (TcpCwt) murine pyelonephritis models was significantly higher compared with that in kidney homogenates from tcpC knockout CFT073 (TcpC‑/‑) models. In vitro, TcpCwt dose‑dependently promoted MIP‑2 secretion in HEK‑293 cells. The concentration of MIP‑2 in culture supernatants of HEK‑293 co‑cultured with TcpCwt was profoundly higher compared with that of HEK‑293 co‑cultured with TcpC‑/‑. In the presence of anti‑TcpC antibody, the enhancement effect of TcpCwt on MIP‑2 production was completely abrogated, suggesting that the enhanced production of MIP‑2 was mediated by secreted TcpC. Furthermore, it was demonstrated that TcpC‑/‑ treatment had no effect on the p38 mitogen activated protein kinase (MAPK) signaling pathway, while TcpCwt treatment resulted in the activation of p38 MAPK in HEK‑293 cells, as indicated by a simultaneous increase in p38 and phosphorylated‑p38. In addition, inhibition of p38 MAPK with SB203580 significantly decreased MIP‑2 concentration and neutrophil recruitment activity in the supernatants of HEK‑293 cells co‑cultured with TcpCwt. This indicates that TcpC may promote MIP‑2 production in kidney cells through the p38 MAPK signaling pathway. Taken together, the data of the present study demonstrated that TcpC can induce MIP‑2 production, which may contribute to the characteristic histological change associated with pyelonephritis. This data has provided novel evidence to further clarify the pathogenesis of pyelonephritis and novel directions on the pathogenicity of TcpC‑secreting UPEC.

TLR4 signaling induces TLR3 up-regulation in alveolar macrophages during acute lung injury

Acute lung injury is a life-threatening inflammatory response caused by severe infection. Toll-like receptors in alveolar macrophages (AMΦ) recognize the molecular constituents of pathogens and activate the host's innate immune responses. Numerous studies have documented the importance of TLR-TLR cross talk, but few studies have specifically addressed the relationship between TLR4 and TLR3. We explored a novel mechanism of TLR3 up-regulation that is induced by LPS-TLR4 signaling in a dose- and time-dependent manner in AMΦ from C57BL/6 mice, while the LPS-induced TLR3 expression was significantly reduced in TLR4^-/- and Myd88^-/- mice and following pretreatment with a NF-κB inhibitor. The enhanced TLR3 up-regulation in AMΦ augmented the expression of cytokines and chemokines in response to sequential challenges with LPS and Poly I:C, a TLR3 ligand, which was physiologically associated with amplified AMΦ-induced PMN migration into lung alveoli. Our study demonstrates that the synergistic effect between TLR4 and TLR3 in macrophages is an important determinant in acute lung injury and, more importantly, that TLR3 up-regulation is dependent on TLR4-MyD88-NF-κB signaling. These results raise the possibility that bacterial infections can induce sensitivity to viral infections, which may have important implications for the therapeutic manipulation of the innate immune system.

Estimating Causal Effects of Local Air Pollution on Daily Deaths: Effect of Low Levels

BACKGROUND

Although many time-series studies have established associations of daily pollution variations with daily deaths, there are fewer at low concentrations, or focused on locally generated pollution, which is becoming more important as regulations reduce regional transport. Causal modeling approaches are also lacking.

OBJECTIVE

We used causal modeling to estimate the impact of local air pollution on mortality at low concentrations.

METHODS

Using an instrumental variable approach, we developed an instrument for variations in local pollution concentrations that is unlikely to be correlated with other causes of death, and examined its association with daily deaths in the Boston, Massachusetts, area. We combined height of the planetary boundary layer and wind speed, which affect concentrations of local emissions, to develop the instrument for particulate matter ≤ 2.5 μm (PM2.5), black carbon (BC), or nitrogen dioxide (NO2) variations that were independent of year, month, and temperature. We also used Granger causality to assess whether omitted variable confounding existed.

RESULTS

We estimated that an interquartile range increase in the instrument for local PM2.5 was associated with a 0.90% increase in daily deaths (95% CI: 0.25, 1.56). A similar result was found for BC, and a weaker association with NO2. The Granger test found no evidence of omitted variable confounding for the instrument. A separate test confirmed the instrument was not associated with mortality independent of pollution. Furthermore, the association remained when all days with PM2.5 concentrations > 30 μg/m3 were excluded from the analysis (0.84% increase in daily deaths; 95% CI: 0.19, 1.50).

CONCLUSIONS

We conclude that there is a causal association of local air pollution with daily deaths at concentrations below U.S. EPA standards. The estimated attributable risk in Boston exceeded 1,800 deaths during the study period, indicating that important public health benefits can follow from further control efforts. Citation: Schwartz J, Bind MA, Koutrakis P. 2017. Estimating causal effects of local air pollution on daily deaths: effect of low levels. Environ Health Perspect 125:23-29; http://dx.doi.org/10.1289/EHP232.

TP53-dependent autophagy links the ATR-CHEK1 axis activation to proinflammatory VEGFA production in human bronchial epithelial cells exposed to fine particulate matter (PM2.5)

ABSTARCT Epidemiological and clinical studies have increasingly shown that fine particulate matter (PM2.5) is associated with a number of pathological respiratory diseases, such as bronchitis, asthma, and chronic obstructive pulmonary disease, which share the common feature of airway inflammation induced by particle exposure. Thus, understanding how PM2.5 triggers inflammatory responses in the respiratory system is crucial for the study of PM2.5 toxicity. In the current study, we found that exposing human bronchial epithelial cells (immortalized Beas-2B cells and primary cells) to PM2.5 collected in the winter in Wuhan, a city in southern China, induced a significant upregulation of VEGFA (vascular endothelial growth factor A) production, a signaling event that typically functions to control chronic airway inflammation and vascular remodeling. Further investigations showed that macroautophagy/autophagy was induced upon PM2.5 exposure and then mediated VEGFA upregulation by activating the SRC (SRC proto-oncogene, non-receptor tyrosine kinase)-STAT3 (signal transducer and activator of transcription 3) pathway in bronchial epithelial cells. By exploring the upstream signaling events responsible for autophagy induction, we revealed a requirement for TP53 (tumor protein p53) activation and the expression of its downstream target DRAM1 (DNA damage regulated autophagy modulator 1) for the induction of autophagy. These results thus extend the role of TP53-DRAM1-dependent autophagy beyond cell fate determination under genotoxic stress and to the control of proinflammatory cytokine production. Moreover, PM2.5 exposure strongly induced the activation of the ATR (ATR serine/threonine kinase)-CHEK1/CHK1 (checkpoint kinase 1) axis, which subsequently triggered TP53-dependent autophagy and VEGFA production in Beas-2B cells. Therefore, these findings suggest a novel link between processes regulating genomic integrity and airway inflammation via autophagy induction in bronchial epithelial cells under PM2.5 exposure.

Dynamic protein coronas revealed as a modulator of silver nanoparticle sulphidation in vitro

Proteins adsorbing at nanoparticles have been proposed as critical toxicity mediators and are included in ongoing efforts to develop predictive tools for safety assessment. Strongly attached proteins can be isolated, identified and correlated to changes in nanoparticle state, cellular association or toxicity. Weakly attached, rapidly exchanging proteins are also present at nanoparticles, but are difficult to isolate and have hardly been examined. Here we study rapidly exchanging proteins and show for the first time that they have a strong modulatory effect on the biotransformation of silver nanoparticles. Released silver ions, known for their role in particle toxicity, are found to be trapped as silver sulphide nanocrystals within the protein corona at silver nanoparticles in serum-containing cell culture media. The strongly attached corona acts as a site for sulphidation, while the weakly attached proteins reduce nanocrystal formation in a serum-concentration-dependent manner. Sulphidation results in decreased toxicity of Ag NPs.

The biomolecule layer adsorbed at the nanoparticle surface and defined as protein corona affects the nanoparticle biophysical properties and functions. Here, the authors suggest that rapidly-exchanging proteins on the outermost layer of the corona modulate sulphidation of silver nanoparticles in vitro.

Nanoparticle Uptake: The Phagocyte Problem

Phagocytes are key cellular participants determining important aspects of host exposure to nanomaterials, initiating clearance, biodistribution and the tenuous balance between host tolerance and adverse nanotoxicity. Macrophages in particular are believed to be among the first and primary cell types that process nanoparticles, mediating host inflammatory and immunological biological responses. These processes occur ubiquitously throughout tissues where nanomaterials are present, including the host mononuclear phagocytic system (MPS) residents in dedicated host filtration organs (i.e., liver, kidney spleen, and lung). Thus, to understand nanomaterials exposure risks it is critical to understand how nanomaterials are recognized, internalized, trafficked and distributed within diverse types of host macrophages and how possible cell-based reactions resulting from nanomaterial exposures further inflammatory host responses in vivo. This review focuses on describing macrophage-based initiation of downstream hallmark immunological and inflammatory processes resulting from phagocyte exposure to and internalization of nanomaterials.

Inflammatory Cytokines Contribute to Asbestos-Induced Injury of Mesothelial Cells

BACKGROUND

Several diseases have been related to asbestos exposure, including the pleural tumor mesothelioma. The mechanism of pleural injury by asbestos fibers is not yet fully understood. The inflammatory response with release of mediators leading to a dysregulation of apoptosis may play a pivotal role in the pathophysiology of asbestos-induced pleural disease.

OBJECTIVE

To determine whether pro-inflammatory cytokines produced by asbestos-exposed pleural mesothelial cells modify the injury induced by the asbestos.

METHODS

Mouse pleural mesothelial cells (PMC) were exposed to crocidolite or chrysotile asbestos fibers (3.0 μg/cm(2)) for 4, 24, or 48 h and assessed for viability, necrosis and apoptosis, and the production of cytokines IL-1β, IL-6 and macrophage inflammatory protein-2 (MIP-2). Cells exposed to fibers were also treated with antibodies anti-IL-1β, anti-IL-6, anti- IL-1β+anti-IL-6 or anti-MIP-2 or their irrelevant isotypes, and assessed for apoptosis and necrosis. Non-exposed cells and cells treated with wollastonite, an inert particle, were used as controls.

RESULTS

Mesothelial cells exposed to either crocidolite or chrysotile underwent both apoptosis and necrosis and released cytokines IL-1β, IL-6 and MIP-2. In the crocidolite group, apoptosis and the levels of all cytokines were higher than in the chrysotile group, at comparable concentrations. Neutralization of IL-1β andIL-6, but not MIP-2, inhibited apoptosis and necrosis, especially in the cells exposed to crocidolite fibers.

CONCLUSIONS

Both crocidolite and chrysotile asbestos fibers induced apoptosis and produced an acute inflammatory response characterized by elevated levels of IL-1β, IL-6 and MIP-2 in cultured mouse PMC. IL-1β and IL-6, but not MIP-2, were shown to contribute to asbestos-induced injury, especially in the crocidolite group.

Inhibitory effects of Cnidium monnieri fruit extract on pulmonary inflammation in mice induced by cigarette smoke condensate and lipopolysaccharide

The aim of this study was to investigate the inhibitory effect of Cnidium monnieri fruit (CM) extracts on pulmonary inflammation induced in mice by cigarette smoke condensate (CSC) and lipopolysaccharide (LPS). Pulmonary inflammation was induced by intratracheal instillation of LPS and CSC five times within 12 days. CM extract was administered orally at a dose of 50 or 200 mg·kg(-1). The number of inflammatory cells in the bronchoalveolar lavage fluid was counted using a fluorescence activated cell sorter. Inflammatory mediator levels were determined by enzyme-linked immunosorbent assay. The administration of LPS and CSC exacerbated airway hyper-responsiveness (AHR) and induced an accumulation of inflammatory cells and mediators, and led to histological changes. However, these responses are modulated by treatment with CM, and the treatment with CM extract produces similar or more extensive results than the treatment with cyclosporin A (CSA). CM extract may have an inhibitory effect on pulmonary inflammation related with chronic obstructive pulmonary disease.

Heme oxygenase-1 dysregulation in the brain: implications for HIV-associated neurocognitive disorders

Heme oxygenase-1 (HO-1) is a highly inducible and ubiquitous cellular enzyme that subserves cytoprotective responses to toxic insults, including inflammation and oxidative stress. In neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease and multiple sclerosis, HO-1 expression is increased, presumably reflecting an endogenous neuroprotective response against ongoing cellular injury. In contrast, we have found that in human immunodeficiency virus (HIV) infection of the brain, which is also associated with inflammation, oxidative stress and neurodegeneration, HO-1 expression is decreased, likely reflecting a unique role for HO-1 deficiency in neurodegeneration pathways activated by HIV infection. We have also shown that HO-1 expression is significantly suppressed by HIV replication in cultured macrophages which represent the primary cellular reservoir for HIV in the brain. HO-1 deficiency is associated with release of neurotoxic levels of glutamate from both HIV-infected and immune-activated macrophages; this glutamate-mediated neurotoxicity is suppressed by pharmacological induction of HO-1 expression in the macrophages. Thus, HO-1 induction could be a therapeutic strategy for neuroprotection against HIV infection and other neuroinflammatory brain diseases. Here, we review various stimuli and signaling pathways regulating HO-1 expression in macrophages, which could promote neuronal survival through HO-1-modulation of endogenous antioxidant and immune modulatory pathways, thus limiting the oxidative stress that can promote HIV disease progression in the CNS. The use of pharmacological inducers of endogenous HO-1 expression as potential adjunctive neuroprotective therapeutics in HIV infection is also discussed.

Early effect of tidal volume on lung injury biomarkers in surgical patients with healthy lungs

BACKGROUND

The early biological impact of short-term mechanical ventilation on healthy lungs is unknown. The authors aimed to characterize the immediate tidal volume (VT)-related changes on lung injury biomarkers in patients with healthy lungs and low risk of pulmonary complications.

METHODS

Twenty-eight healthy patients for knee replacement surgery were prospectively randomized to volume-controlled ventilation with VT 6 (VT6) or 10 (VT10) ml/kg predicted body weight. General anesthesia and other ventilatory parameters (positive end-expiratory pressure, 5 cm H2O, FIO2, 0.5, respiratory rate titrated for normocapnia) were managed similarly in the two groups. Exhaled breath condensate and blood samples were collected for nitrite, nitrate, tumor necrosis factor-α, interleukins-1β, -6, -8, -10, -11, neutrophil elastase, and Clara Cell protein 16 measurements, at the onset of ventilation and 60 min later.

RESULTS

No significant differences in biomarkers were detected between the VT groups at any time. The coefficient of variation of exhaled breath condensate nitrite and nitrate decreased in the VT6 but increased in the VT10 group after 60-min ventilation. Sixty-minute ventilation significantly increased plasma neutrophil elastase levels in the VT6 (35.2 ± 30.4 vs. 56.4 ± 51.7 ng/ml, P = 0.008) and Clara Cell protein 16 levels in the VT10 group (16.4 ± 8.8 vs. 18.7 ± 9.5 ng/ml, P = 0.015). Exhaled breath condensate nitrite correlated with plateau pressure (r = 0.27, P = 0.042) and plasma neutrophil elastase (r = 0.44, P = 0.001). Plasma Clara Cell protein 16 correlated with compliance (r = 0.34, P = 0.014).

CONCLUSIONS

No tidal volume-related changes were observed in the selected lung injury biomarkers of patients with healthy lungs after 60-min ventilation. Plasma neutrophil elastase and plasma Clara Cell protein 16 might indicate atelectrauma and lung distention, respectively.

Role of metal oxide nanoparticles in histopathological changes observed in the lung of welders

Background

Although major concerns exist regarding the potential consequences of human exposure to nanoparticles (NP), no human toxicological data is currently available. To address this issue, we took welders, who present various adverse respiratory outcomes, as a model population of occupational exposure to NP.

The aim of this study was to evaluate if welding fume-issued NP could be responsible, at least partially, in the lung alterations observed in welders.

Methods

A combination of imaging and material science techniques including ((scanning) transmission electron microscopy ((S)TEM), energy dispersive X-ray (EDX), and X-ray microfluorescence (μXRF)), was used to characterize NP content in lung tissue from 21 welders and 21 matched control patients. Representative NP were synthesized, and their effects on macrophage inflammatory secretome and migration were evaluated, together with the effect of this macrophage inflammatory secretome on human lung primary fibroblasts differentiation.

Results

Welding-related NP (Fe, Mn, Cr oxides essentially) were identified in lung tissue sections from welders, in macrophages present in the alveolar lumen and in fibrous regions. In vitro macrophage exposure to representative NP (Fe₂O₃, Fe₃O₄, MnFe₂O₄ and CrOOH) induced the production of a pro-inflammatory secretome (increased production of CXCL-8, IL-1ß, TNF-α, CCL-2, −3, −4, and to a lesser extent IL-6, CCL-7 and −22), and all but Fe₃O₄ NP induce an increased migration of macrophages (Boyden chamber). There was no effect of NP-exposed macrophage secretome on human primary lung fibroblasts differentiation.

Conclusions

Altogether, the data reported here strongly suggest that welding-related NP could be responsible, at least in part, for the pulmonary inflammation observed in welders. These results provide therefore the first evidence of a link between human exposure to NP and long-term pulmonary effects.

Particles internalization, oxidative stress, apoptosis and pro-inflammatory cytokines in alveolar macrophages exposed to cement dust

Exposure to cement dust is one of the most common occupational dust exposures worldwide, but the mechanism of toxicity has not been fully elucidated. Cement dust (N) and clinker (C) samples collected from Nigeria and another sample of cement dust (U) collected from USA were evaluated using alveolar macrophage (NR8383) cell culture to determine the contribution of different sources of cement dust in the severity of cement dust toxicity. Cement dust particles internalization and morphologic alterations using transmission electron microscopy (TEM), cytotoxicity, apoptotic cells induction, intracellular reactive oxygen species generation, glutathione reduction, TNF-α, IL-1β, and CINC-3 secretion in alveolar macrophages (NR8383) exposed to cement dust and clinker samples were determined. Particles were internalized into the cytoplasmic vacuoles, with cells exposed to U showing increased cell membrane blebbing. Also, NR8383 exposed to U show more significant ROS generation, apoptotic cells induction and decreased glutathione. Interleukin-1β and TNF-α secretion were significantly more in cells exposed to both cement dust samples compared with clinker, while CINC-3 secretion was significantly more in cells exposed to clinker (p < 0.05). Endocytosis, oxidative stress induced-apoptosis and induction of pro-inflammatory cytokines may be key mechanisms of cement dust immunotoxicity in the lung and toxicity may be factory dependent.

Role of surface charge and oxidative stress in cytotoxicity and genotoxicity of graphene oxide towards human lung fibroblast cells

Recently, attempts have been made to apply graphene oxide (GO) in the field of biology and medicine, such as DNA sensing and drug delivery with some necessary modifications. Therefore, the toxicity of GO must be evaluated before it is applied further in biomedicine. In this paper, the cytotoxicity and genotoxicity of GO to human lung fibroblast (HLF) cells have been assessed with methyl thiazolyl tetrazolium (MTT), sub-G1 measurement and comet assays, and the mechanism of its toxicity has been explored. Various modifications of GO have been made to help us determine the factors which could affect the toxicity of GO. The results indicated that cytotoxicity and genotoxicity of GO to HLF cells were concentration dependent, and the genotoxicity induced by GO was more severe than the cytotoxicity to HLF cells. Oxidative stress mediated by GO might explain the reason of its toxic effect. Furthermore, the electronic charge on the surface of GO would play a very important role in the toxicity of GO to HLF cells.