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Abigail C Burr,1,* Jalene V Velazquez,1,* Arzu Ulu,1 Rohan Kamath,1 Sang Yong Kim,1 Amanpreet K Bilg,1 Aileen Najera,1 Iman Sultan,1 Jon K Botthoff,2 Emma Aronson,3 Meera G Nair,1 Tara M Nordgren1 1Division of Biomedical Sciences, University of California Riverside, Riverside, CA, 92521, USA; 2Center for Conservation Biology, University of California Riverside, Riverside, CA, 92521, USA; 3Department of Plant Pathology and Microbiology, University of California Riverside, Riverside, CA, 92521, USA*These authors contributed equally to this workCorrespondence: Tara M NordgrenDivision of Biomedical Sciences, University of California Riverside, 92521 University Avenue, Riverside, CA, 92521, USATel +1 951 827 3148Email tmnordgren@gmail.comPurpose: The Salton Sea, California’s largest lake, is designated as an agricultural drainage reservoir. In recent years, the lake has experienced shrinkage due to reduced water sources, increasing levels of aerosolized dusts in surrounding regions. Communities surrounding the Salton Sea have increased asthma prevalence versus the rest of California; however, a connection between dust inhalation and lung health impacts has not been defined.Methods: We used an established intranasal dust exposure murine model to study the lung inflammatory response following single or repetitive (7-day) exposure to extracts of dusts collected in regions surrounding the Salton Sea (SSDE), complemented with in vitro investigations assessing SSDE impacts on the airway epithelium.Results: In these investigations, single or repetitive SSDE exposure induced significant lung inflammatory cytokine release concomitant with neutrophil influx. Repetitive SSDE exposure led to significant lung eosinophil recruitment and altered expression of genes associated with allergen-mediated immune response, including Clec4e. SSDE treatment of human bronchial epithelial cells (BEAS-2B) induced inflammatory cytokine production at 5- and 24-hours post-treatment. When BEAS-2B were exposed to protease activity-depleted SSDE (PDSSDE) or treated with SSDE in the context of protease-activated receptor-1 and − 2 antagonism, inflammatory cytokine release was decreased. Furthermore, repetitive exposure to PDSSDE led to decreased neutrophil and eosinophilic influx and IL-6 release in mice compared to SSDE-challenged mice.Conclusion: These investigations demonstrate potent lung inflammatory responses and tissue remodeling in response to SSDE, in part due to environmental proteases found within the dusts. These studies provide the first evidence supporting a link between environmental dust exposure, protease-mediated immune activation, and respiratory disease in the Salton Sea region.Keywords: Salton Sea, dust exposure, lung inflammation, asthma, proteases, protease-activated receptors

Tissue remodeling in pulmonary disease irreversibly alters lung functionality and impacts quality of life. Mechanical ventilation is amongst the few pulmonary interventions to aid respiration, but can be harmful or fatal, inducing excessive regional (i.e., local) lung strains. Previous studies have advanced understanding of diseased global-level lung response under ventilation, but do not adequately capture the critical local-level response. Here, we pair a custom-designed pressure-volume ventilator with new applications of digital image correlation, to directly assess regional strains in the fibrosis-induced ex-vivo mouse lung, analyzed via regions of interest. We discuss differences between diseased and healthy lung mechanics, such as distensibility, heterogeneity, anisotropy, alveolar recruitment, and rate dependencies. Notably, we compare local and global compliance between diseased and healthy states by assessing the evolution of pressure-strain and pressure-volume curves resulting from various ventilation volumes and rates. We find fibrotic lungs are less-distensible, with altered recruitment behaviors and regional strains, and exhibit disparate behaviors between local and global compliance. Moreover, these diseased characteristics show volume-dependence and rate trends. Ultimately, we demonstrate how fibrotic lungs may be particularly susceptible to damage when contrasted to the strain patterns of healthy counterparts, helping to advance understanding of how ventilator induced lung injury develops.

Respiratory pathologies alter the structure of the lung and impact its mechanics. Mice are widely used in the study of lung pathologies, but there is a lack of fundamental mechanical measurements assessing the interdependent effect of varying inflation volumes and cycling frequency. In this study, the mechanical properties of five male C57BL/6J mice (29-33 weeks of age) lungs were evaluated ex vivo using our custom-designed electromechanical, continuous measure ventilation apparatus. We comprehensively quantify and analyze the effect of loading volumes (0.3, 0.5, 0.7, 0.9 ml) and breathing rates (5, 10, 20 breaths per minute) on pulmonary inflation and deflation mechanical properties. We report means of static compliance between 5.4-16.1 µl/cmH2O, deflation compliance of 5.3-22.2 µl/cmH2O, percent relaxation of 21.7-39.1%, hysteresis of 1.11-7.6 ml•cmH2O, and energy loss of 39-58% for the range of four volumes and three rates tested, along with additional measures. We conclude that inflation volume was found to significantly affect hysteresis, static compliance, starting compliance, top compliance, deflation compliance, and percent relaxation, and cycling rate was found to affect only hysteresis, energy loss, percent relaxation, static compliance and deflation compliance.

Defense of the human body against damaging and pathogenic insults is a heavily regulated affair. A primary mechanism of defense at sites of insult are soluble mediators whose defensive maneuvers increase barrier integrity and promote pro-reparative and resolution processes. IL-22 is a cytokine in the IL-10 cytokine family that has garnered increased attention in recent years due to its intimate link in promoting resolution of inflammatory insults, while simultaneously being over expressed in certain fibrotic and chronic inflammatory-skewed diseases. The spatial action of IL-22 centers around the barrier sites of the body, including the skin, lungs, and gut mucosa. As such, a detailed understanding of the role of this cytokine, the producers and responders, and the diseases resulting from over- or under-expression have prominent impacts on a variety of disease outcomes. Herein we present a comprehensive review of IL-22; from historical perspectives and initial discovery, as well as more recent data that dramatically expands on the cellular sources and impact of this cytokine. We aim to showcase the duality of IL-22 and highlight addressable gaps in the field of IL-22 crosstalk and impacts at the ever-important mucosal and tissue barrier sites., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Introduction. Staphylococcus aureus is the leading cause of acute medical implant infections, representing a significant modern medical concern. The success of S. aureus as a pathogen in these cases resides in its arsenal of virulence factors, resistance to multiple antimicrobials, mechanisms of immune modulation, and ability to rapidly form biofilms associated with implant surfaces. S. aureus device-associated, biofilm-mediated infections are often persistent and notoriously difficult to treat, skewing innate immune responses to promote chronic reoccurring infections. While relatively little is known of the role neutrophils play in response to acute S. aureus biofilm infections, these effector cells must be efficiently recruited to sites of infection via directed chemotaxis. Here we investigate the effects of modulating CXC chemokine receptor 2 (CXCR2) activity, predominantly expressed on neutrophils, during S. aureus implant-associated infection. Hypothesis. We hypothesize that modulation of CXCR2 expression and/or signalling activities during S. aureus infection, and thus neutrophil recruitment, extravasation and antimicrobial activity, will affect infection control and bacterial burdens in a mouse model of implant-associated infection. Aim. This investigation aims to elucidate the impact of altered CXCR2 activity during S. aureus biofilm-mediated infection that may help develop a framework for an effective novel strategy to prevent morbidity and mortality associated with implant infections. Methodology. To examine the role of CXCR2 during S. aureus implant infection, we employed a mouse model of indwelling subcutaneous catheter infection using a community-associated methicillin-resistant S. aureus (MRSA) strain. To assess the role of CXCR2 induction or inhibition during infection, treatment groups received daily intraperitoneal doses of either Lipocalin-2 (Lcn2) or AZD5069, respectively. At the end of the study, catheters and surrounding soft tissues were analysed for bacterial burdens and dissemination, and Cxcr2 transcription within the implant-associated tissues was quantified. Results. Mice treated with Lcn2 developed higher bacterial burdens within the soft tissue surrounding the implant site, which was associated with increased Cxcr2 expression. AZD5069 treatment also resulted in increased implant- and tissues-associated bacterial titres, as well as enhanced Cxcr2 expression. Conclusion. Our results demonstrate that CXCR2 plays an essential role in regulating the severity of S. aureus implant-associated infections. Interestingly, however, perturbation of CXCR2 expression or signalling both resulted in enhanced Cxcr2 transcription and elevated implant-associated bacterial burdens. Thus, CXCR2 appears finely tuned to efficiently recruit effector cells and mediate control of S. aureus biofilm-mediated infection.

Increased ventilator use during the COVID-19 pandemic resurrected persistent questions regarding mechanical ventilation including the difference between physiological and artificial breathing induced by ventilators (i.e., positive- versus negative-pressure ventilation, PPV vs NPV). To address this controversy, we compare murine specimens subjected to PPV and NPV in ex vivo quasi-static loading and quantify pulmonary mechanics via measures of quasi-static and dynamic compliances, transpulmonary pressure, and energetics when varying inflation frequency and volume. Each investigated mechanical parameter yields instance(s) of significant variability between ventilation modes. Most notably, inflation compliance, percent relaxation, and peak pressure are found to be consistently dependent on the ventilation mode. Maximum inflation volume and frequency note varied dependencies contingent on the ventilation mode. Contradictory to limited previous clinical investigations of oxygenation and end-inspiratory measures, the mechanics-focused comprehensive findings presented here indicate lung properties are dependent on loading mode, and importantly, these dependencies differ between smaller versus larger mammalian species despite identical custom-designed PPV/NPV ventilator usage. Results indicate that past contradictory findings regarding ventilation mode comparisons in the field may be linked to the chosen animal model. Understanding the differing fundamental mechanics between PPV and NPV may provide insights for improving ventilation strategies and design to prevent associated lung injuries., (© 2023. The Author(s).)

Concentrated animal feeding operations (CAFOs) are responsible for the production of global greenhouse gases and harmful environmental pollutants including hydrogen sulfide, ammonia, and particulate matter. Swine farmers are frequently exposed to organic dust that is proinflammatory in the lung and are thus at greater risk of developing pneumonia, asthma, and other respiratory conditions. In addition to respiratory disease, air pollutants are directly associated with altered gastrointestinal (GI) physiology and the development of GI diseases, thereby highlighting the gut-lung axis in disease progression. Instillation of hog dust extract (HDE) for 3 wk has been reported to promote the development of chronic airway inflammation in mice, however, the impact of HDE exposure on intestinal homeostasis is poorly understood. We report that 3-wk intranasal exposure of HDE is associated with increased intestinal macromolecule permeability and elevated serum endotoxin concentrations in C57BL/6J mice. In vivo studies also indicated mislocalization of the epithelial cell adhesion protein, E-cadherin, in the colon as well as an increase in the proinflammatory cytokine, Tnfα , in the proximal colon. Moreover, mRNA expression of the Paneth cell-associated marker, Lyz1 , was increased the proximal colon, whereas the expression of the goblet cell marker, Muc2 , was unchanged in the epithelial cells of the ileum, cecum, and distal colon. These results demonstrate that airway exposure to CAFOs dusts promote airway inflammation and modify the gastrointestinal tract to increase intestinal permeability, induce systemic endotoxemia, and promote intestinal inflammation. Therefore, this study identifies complex physiological consequences of chronic exposure to organic dusts derived from CAFOs on the gut-lung axis. NEW & NOTEWORTHY Agricultural workers have a higher prevalence of occupational respiratory symptoms and are at greater risk of developing respiratory diseases. However, gastrointestinal complications have also been reported, yet the intestinal pathophysiology is understudied. This work is novel because it emphasizes the role of an inhaled environmental pollutant on the development of intestinal pathophysiological outcomes. This work will provide foundation for other studies evaluating how agricultural dusts disrupts host physiology and promotes debilitating gastrointestinal and systemic disorders.

The role of pulmonary free fatty acid receptor 4 (FFAR4) is not fully elucidated and we aimed to clarify the impact of FFAR4 on the pulmonary immune response and return to homeostasis. We employed a known high-risk human pulmonary immunogenic exposure to extracts of dust from swine confinement facilities (DE). WT and Ffar4 -null mice were repetitively exposed to DE via intranasal instillation and supplemented with docosahexaenoic acid (DHA) by oral gavage. We sought to understand if previous findings of DHA-mediated attenuation of the DE-induced inflammatory response are FFAR4-dependent. We identified that DHA mediates anti-inflammatory effects independent of FFAR4 expression, and that DE-exposed mice lacking FFAR4 had reduced immune cells in the airways, epithelial dysplasia, and impaired pulmonary barrier integrity. Analysis of transcripts using an immunology gene expression panel revealed a role for FFAR4 in lungs related to innate immune initiation of inflammation, cytoprotection, and immune cell migration. Ultimately, the presence of FFAR4 in the lung may regulate cell survival and repair following immune injury, suggestive of potential therapeutic directions for pulmonary disease.

Dietary long-chain omega-3 polyunsaturated fatty acids (n-3 PUFA) and their pro-resolving metabolites are protective against atherosclerotic disease, and ameliorate systemic inflammatory conditions including lupus erythematosus, psoriasis, and bronchial asthma. Organic bioaerosol inhalation is a common and injurious hazard associated with agricultural occupations such as work in swine concentrated animal feeding operations (CAFOs) and is known to increase the risk for developing respiratory conditions such as asthma and COPD. Nearly all cells secrete membrane-bound vesicles (extracellular vesicles, EVs) that have the capacity to transmit protein, nucleic acid, and lipid signaling mediators between cells. Using a polymer-based isolation technique (ExoQuick, PEG) followed by ultracentrifugation, EVs were isolated from CAFO dust extracts, and were quantified and partially characterized. Here, we investigated the role of the n-3 PUFA docosahexaenoic acid (DHA) as a component of n-6 to n-3 PUFA mixtures used to recapitulate physiologically relevant dietary ratios in the resolution of inflammatory injury caused by exposure to EVs carried by agricultural organic dust in vitro. Primary human bronchial epithelial cells, fibroblasts and monocyte-derived macrophages were exposed to EVs isolated from swine CAFO dust. Cells were treated with mixtures of n-6 and n-3 PUFA during recovery from the EV-induced injury. CAFO dust extract (DE) was found to contain EVs that contributed significantly to the overall consequences of exposure to complete DE. DHA-rich PUFA ratios inhibited DE-derived EV-induced proinflammatory cytokine release dose-dependently. DHA-rich PUFA ratios also reversed the damaging effects of EVs on recellularization of lung matrix scaffolds, accelerated wound healing, and stimulated the release of pro-resolution mediators. These results underscore the importance of n-3 PUFA as anti-inflammatory compounds during recovery from EV-laden environmental dust exposure in the context of cellular responses in vitro, warranting future translational studies., (© 2023. The Author(s).)

Normal pregnancy relies on inflammation for implantation, placentation, and parturition, but uncontrolled inflammation can lead to poor maternal and infant outcomes. Maternal diet is one modifiable factor that can impact inflammation. Omega-3 and -6 fatty acids obtained through the diet are metabolized into bioactive compounds that effect inflammation. Recent evidence has shown that the downstream products of omega-3 and -6 fatty acids may influence physiology during pregnancy. In this review, the current knowledge relating to omega-3 and omega-6 metabolites during pregnancy will be summarized.

Soil-transmitted helminth (STH) infections impact billions of individuals globally; however, there is a need to clarify the long-term impacts of these infections on pulmonary health owing to their transient migration and subsequent damage to the lungs. In mouse models of these infections using Nippostrongylus brasiliensis , lung pathology persists at later time points post single infection. These studies also indicate the persistent transcriptional expression of resistin-like molecule α (RELMα), an immunomodulatory protein induced in type 2 immunity and alternatively activated macrophages. Using constitutive and tamoxifen-inducible cell-specific RELMα knockout mouse strains, we identified that epithelial- and myeloid-derived RELMα protein remained elevated at 30 days post infection and altered the immune cell signature and gene expression in lung compartments. Histopathological assessment of alveolar damage revealed a role for RELMα in tissue repair, suggesting the importance of sustained RELMα expression for lung recovery from helminth infection. Acellular three-dimensional (3D) lung scaffolds were prepared from the lungs of wild-type (WT), RELMα KO-naive, or 30 days post N . brasiliensis -infected mice to assess their ability to support epithelial cell growth. N . brasiliensis infection significantly altered the scaffold and impaired epithelial cell growth and metabolic activity, especially in the RELMα KO scaffolds. These findings underscore a need to identify the long-term impacts of helminth infection on human pulmonary disease, particularly as alveolar destruction can develop into chronic obstructive pulmonary disease (COPD), which remains among the top global causes of death. Translation of these findings to human protein resistin, with sequence homology to RELMα therapeutic opportunities in lung repair., Competing Interests: Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Pulmonary diseases alter lung mechanical properties, can cause loss of function, and necessitate use of mechanical ventilation, which can be detrimental. Investigations of lung tissue (local) scale mechanical properties are sparse compared to that of the whole organ (global) level, despite connections between regional strain injury and ventilation. We examine ex vivo mouse lung mechanics by investigating strain values, local compliance, tissue surface heterogeneity, and strain evolutionary behavior for various inflation rates and volumes. A custom electromechanical, pressure-volume ventilator is coupled with digital image correlation to measure regional lung strains and associate local to global mechanics by analyzing novel pressure-strain evolutionary measures. Mean strains at 5 breaths per minute (BPM) for applied volumes of 0.3, 0.5, and 0.7 ml are 5.0, 7.8, and 11.3%, respectively, and 4.7, 8.8, and 12.2% for 20 BPM. Similarly, maximum strains among all rate and volume combinations range 10.7%-22.4%. Strain values (mean, range, mode, and maximum) at peak inflation often exhibit significant volume dependencies. Additionally, select evolutionary behavior (e.g., local lung compliance quantification) and tissue heterogeneity show significant volume dependence. Rate dependencies are generally found to be insignificant; however, strain values and surface lobe heterogeneity tend to increase with increasing rates. By quantifying strain evolutionary behavior in relation to pressure-volume measures, we associate time-continuous local to global mouse lung mechanics for the first time and further examine the role of volume and rate dependency. The interplay of multiscale deformations evaluated in this work can offer insights for clinical applications, such as ventilator-induced lung injury., (© 2022 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

IL-22 is a unique cytokine that is upregulated in many chronic inflammatory diseases, including asthma, and modulates tissue responses during inflammation. However, the role of IL-22 in the resolution of inflammation and how this contributes to lung repair processes are largely unknown. Here, we tested the hypothesis that IL-22 signaling is critical in inflammation resolution after repetitive exposure to agricultural dust. Using an established mouse model of organic dust extract-induced lung inflammation, we found that IL-22 knockout mice have an enhanced response to agricultural dust as evidenced by an exacerbated increase in infiltrating immune cells and lung pathology as compared to wild-type controls. We further identified that, in response to dust, IL-22 is expressed in airway epithelium and in Ym1+ macrophages found within the parenchyma in response to dust. The increase in IL-22 expression was accompanied by increases in IL-22 receptor IL-22R1 within the lung epithelium. In addition, we found that alveolar macrophages in vivo as well as THP-1 cells in vitro express IL-22, and this expression is modulated by dust exposure. Furthermore, subcellular localization of IL-22 appears to be in the Golgi of resting THP1 human monocytes, and treatment with dust extracts is associated with IL-22 release into the cytosolic compartment from the Golgi reservoirs during dust extract exposure. Taken together, we have identified a significant role for macrophage-mediated IL-22 signaling that is activated in dust-induced lung inflammation in mice., (Copyright © 2022. Published by Elsevier Inc.)

Lung cancer is the leading cause of cancer-related deaths worldwide, with increased risk being associated with unresolved or chronic inflammation. Agricultural and livestock workers endure significant exposure to agricultural dusts on a routine basis; however, the chronic inflammatory and carcinogenic effects of these dust exposure is unclear. We have developed a chronic dust exposure model of lung carcinogenesis in which mice were intranasally challenged three times a week for 24 weeks, using an aqueous dust extract (HDE) made from dust collected in swine confinement facilities. We also treated mice with the omega-3-fatty acid lipid mediator, aspirin-triggered resolvin D1 (AT-RvD1) to provide a novel therapeutic strategy for mitigating the inflammatory and carcinogenic effects of HDE. Exposure to HDE resulted in significant immune cell influx into the lungs, enhanced lung tumorigenesis, severe tissue pathogenesis, and a pro-inflammatory and carcinogenic gene signature, relative to saline-exposed mice. AT-RvD1 treatment mitigated the dust-induced inflammatory response but did not protect against HDE + NNK-enhanced tumorigenesis. Our data suggest that chronic HDE exposure induces a significant inflammatory and pro-carcinogenic response, whereas treatment with AT-RvD1 dampens the inflammatory responses, providing a strong argument for the therapeutic use of AT-RvD1 to mitigate chronic inflammation.

In agriculture industries, workers are at increased risk for developing pulmonary diseases due to inhalation of agricultural dusts, particularly when working in enclosed confinement facilities. Agricultural dusts inhalation leads to unresolved airway inflammation that precedes the development and progression of lung disease. We have previously shown beneficial effects of the omega-3 polyunsaturated fatty acid (ω-3 PUFA) DHA in protecting against the negative inflammatory effects of repetitive dust exposure in the lung. Dietary manipulation of pulmonary disease risk is an attractive and timely approach given the contribution of an increased ω-6 to ω-3 PUFA ratio to low grade inflammation and chronic disease in the Western diet. To prevent any confounding factors that comes with dietary supplementation of ω-3 PUFA (different sources, purity, dose, and duration), we employed a Fat-1 transgenic mouse model that convert ω-6 PUFA to ω-3 PUFA, leading to a tissue ω-6 to ω-3 PUFA ratio of approximately 1:1. Building on our initial findings, we hypothesized that attaining elevated tissue levels of ω-3 PUFA would attenuate agricultural dust-induced lung inflammation and its resolution. To test this hypothesis, we compared wild-type (WT) and Fat-1 transgenic mice in their response to aqueous extracts of agricultural dust (DE). We also used a soluble epoxide hydrolase inhibitor (sEH) to potentiate the effects of ω-3 PUFA, since sEH inhibitors have been shown to stabilize the anti-inflammatory P450 metabolites derived from both ω-3 and ω-6 PUFA and promote generation of specialized pro-resolving lipid mediators from ω-3 PUFA. Over a three-week period, mice were exposed to a total of 15 intranasal instillations of DE obtained from swine confinement buildings in the Midwest. We observed genotype and sex-specific differences between the WT vs. Fat-1 transgenic mice in response to repetitive dust exposure, where three-way ANOVA revealed significant main effects of treatment, genotype, and sex. Also, Fat-1 transgenic mice displayed reduced lymphoid aggregates in the lung following DE exposure as compared to WT animals exposed to DE, suggesting improved resilience to the DE-induced inflammatory effects. Overall, our data implicate a protective role of ω-3 FA in the lung following repetitive dust exposure., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ulu, Velazquez, Burr, Sveiven, Yang, Bravo, Hammock and Nordgren.)

Omega-3 and omega-6 fatty acids are important for neonatal development and health. One mechanism by which omega-3 and omega-6 fatty acids exert their effects is through their metabolism into oxylipins and specialized pro-resolving mediators. However, the influence of oxylipins on fetal growth is not well understood. Therefore, the objective of this study was to identify oxylipins present in maternal and umbilical cord plasma and investigate their relationship with infant growth. Liquid chromatography-tandem mass spectrometry was used to quantify oxylipin levels in plasma collected at the time of delivery. Spearman's correlations highlighted significant correlations between metabolite levels and infant growth. They were then adjusted for maternal obesity (normal body mass index (BMI: ≤30 kg/m 2 ) vs. obese BMI (>30 kg/m 2 ) and smoking status (never vs. current/former smoker) using linear regression modeling. A p -value < 0.05 was considered statistically significant. Our study demonstrated a diverse panel of oxylipins from the lipoxygenase pathway present at the time of delivery. In addition, both omega-3 and omega-6 oxylipins demonstrated potential influences on the birth length and weight percentiles. The oxylipins present during pregnancy may influence fetal growth and development, suggesting potential metabolites to be used as biomarkers for infant outcomes.

Background: QuPath is an open-source digital image analyzer notable for its user-friendly design, cross-platform compatibility, and customizable functionality. Since it was first released in 2016, at least 624 publications have reported its use, and it has been applied in a wide spectrum of settings. However, there are currently limited reports of its use in placental tissue. Here, we present the use of QuPath to quantify staining of G-protein coupled receptor 18 (GPR18), the receptor for the pro-resolving lipid mediator Resolvin D2, in placental tissue., Methods: Whole slide images of vascular smooth muscle (VSM) and extravillous trophoblast (EVT) cells stained for GPR18 were annotated for areas of interest. Visual scoring was performed on these images by trained and in-training pathologists, while QuPath scoring was performed with the methodology described herein., Results: Bland-Altman analyses showed that, for the VSM category, the two methods were comparable across all staining levels. For EVT cells, the high-intensity staining level was comparable across methods, but the medium and low staining levels were not comparable., Conclusions: Digital image analysis programs offer great potential to revolutionize pathology practice and research by increasing accuracy and decreasing the time and cost of analysis. Careful study is needed to optimize this methodology further., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Journal of Pathology Informatics.)

Agricultural workers, especially those who work in swine confinement facilities, are at increased risk for developing pulmonary diseases including asthma, chronic obstructive pulmonary disease, and chronic bronchitis due to exposures to fumes, vapors, and organic dust. Repetitive exposure to agricultural dust leads to unresolved inflammation, a common underlying mechanism that worsens lung disease. Besides occupational exposure to dusts, diet also significantly contributes to inflammation and disease progression. Since DHA (docosahexaenoic acid), a polyunsaturated omega-3 fatty acid and its bioactive metabolites have key roles in inflammation resolution, we rationalized that individuals chronically exposed to organic dusts can benefit from dietary modifications. Here, we evaluated the role of DHA in modifying airway inflammation in a murine model of repetitive exposure to an aqueous extract of agricultural dust (three-week exposure to swine confinement dust extract, HDE) and after a one-week resolution/recovery period. We found that mice fed a high DHA diet had significantly increased bronchoalveolar lavage fluid (BALF) levels of DHA-derived resolvins and lower TNFα along with altered plasma levels of endocannabinoids and related lipid mediators. Following the one-week recovery we identified significantly reduced BALF cellularity and cytokine/chemokine release along with increased BALF amphiregulin and resolvins in DHA diet-fed versus control diet-fed mice challenged with HDE. We further report observations on the effects of repetitive HDE exposure on lung Ym1+ and Arg-1+ macrophages. Overall, our findings support a protective role for DHA and identify DHA-derived resolvins and endocannabinoids among the potential mediators of DHA in altering airway inflammation in chronic agricultural dust exposure., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Lipocalin-2 (LCN2) is an inflammatory mediator best known for its role as an innate acute-phase protein. LCN2 mediates the innate immune response to pathogens by sequestering iron, thereby inhibiting pathogen growth. Although LCN2 and its bacteriostatic properties are well studied, other LCN2 functions in the immune response to inflammatory stimuli are less well understood, such as its role as a chemoattractant and involvement in the regulation of cell migration and apoptosis. In the lungs, most studies thus far investigating the role of LCN2 in the immune response have looked at pathogenic inflammatory stimuli. Here, we compile data that explore the role of LCN2 in the immune response to various inflammatory stimuli in an effort to differentiate between protective versus detrimental roles of LCN2.

Background: Perinatal inflammation adversely affects health. Therefore, aims of this IRB-approved study are: (1) compare inflammatory compounds within and between maternal and umbilical cord blood samples at the time of delivery, (2) assess relationships between inflammatory compounds in maternal and cord blood with birth characteristics/outcomes, and (3) assess relationships between blood and placental fat-soluble nutrients with blood levels of individual inflammatory compounds., Methods: Mother-infant dyads were enrolled (n = 152) for collection of birth data and biological samples of maternal blood, umbilical cord blood, and placental tissue. Nutrient levels included: lutein + zeaxanthin; lycopene; α-, β-carotene; β-cryptoxanthin; retinol; α-, γ-, δ-tocopherol. Inflammatory compounds included: tumor necrosis factor-α, superoxide dismutase, interleukins (IL) 1β, 2, 6, 8, 10., Results: Median inflammatory compound levels were 1.2-2.3 times higher in cord vs. maternal blood, except IL2 (1.3 times lower). Multiple significant correlations existed between maternal vs. infant inflammatory compounds (range of r = 0.22-0.48). While relationships existed with blood nutrient levels, the most significant were identified in placenta where all nutrients (except δ-tocopherol) exhibited relationships with inflammatory compounds. Relationships between anti-inflammatory nutrients and proinflammatory compounds were primarily inverse., Conclusion: Inflammation is strongly correlated between mother-infant dyads. Fat-soluble nutrients have relationships with inflammatory compounds, suggesting nutrition is a modifiable factor., Impact: Mother and newborn inflammation status are strongly interrelated. Levels of fat-soluble nutrients in blood, but especially placenta, are associated with blood levels of proinflammatory and anti-inflammatory compounds in both mother and newborn infant. As fat-soluble nutrient levels are associated with blood inflammatory compounds, nutrition is a modifiable factor to modulate inflammation and improve perinatal outcomes., (© 2020. International Pediatric Research Foundation, Inc.)

Introduction: Over 1 billion humans carry infectious helminth parasites that can lead to chronic comorbidities such as anemia and growth retardation in children. Helminths induce a T-helper type 2 (Th2) immune response in the host and can cause severe tissue damage and fibrosis if chronic. We recently reported that mice infected with the soil-transmitted helminth, Nippostrongylus brasiliensis , displayed elevated levels of endocannabinoids (eCBs) in the lung and intestine. eCBs are lipid-signaling molecules that control inflammation; however, their function in infection is not well defined. Materials and Methods: A combination of pharmacological approaches and genetic mouse models was used to investigate roles for the eCB system in inflammatory responses and lung injury in mice during parasitic infection with N. brasiliensis . Results: Hemorrhaging of lung tissue in mice infected with N. brasiliensis was exacerbated by inhibiting peripheral cannabinoid receptor subtype-1 (CB 1 Rs) with the peripherally restricted CB 1 R antagonist, AM6545. In addition, these mice exhibited an increase in nonfunctional alveolar space and prolonged airway eosinophilia compared to vehicle-treated infected mice. In contrast to mice treated with AM6545, infected cannabinoid receptor subtype-2-null mice (Cnr2 -/- ) did not display any changes in these parameters compared to wild-type mice. Conclusions: Roles for the eCB system in Th2 immune responses are not well understood; however, increases in its activity in response to infection suggest an immunomodulatory role. Moreover, these findings suggest a role for eCB signaling at CB 1 Rs but not cannabinoid receptor subtypes-2 in the resolution of Th2 inflammatory responses, which become host destructive over time.

Per the Centers for Disease Control and Prevention, asthma prevalence has steadily risen since the 1980s. Using data from the National Health and Nutrition Examination Survey (NHANES), we investigated associations between milk consumption and pulmonary function (PF). Multivariable analyses were performed, adjusted for a priori potential confounders for lung function, within the eligible total adult population ( n = 11,131) and those self-reporting asthma ( n = 1,542), included the following variables: milk-consumption, asthma diagnosis, forced vital capacity (FVC), FVC%-predicted (%), forced expiratory volume in one-second (FEV 1 ), FEV 1 % and FEV 1 /FVC. Within the total population, FEV 1 % and FVC% were significantly associated with regular (5+ days weekly) consumption of exclusively 1% milk in the prior 30-days (β:1.81; 95% CI: [0.297, 3.325]; p = 0.020 and β:1.27; [0.16, 3.22]; p = 0.046). Among participants with asthma, varied-regular milk consumption in a lifetime was significantly associated with FVC (β:127.3; 95% CI: [13.1, 241.4]; p = 0.002) and FVC% (β:2.62; 95% CI: [0.44, 4.80]; p = 0.006). No association between milk consumption and FEV 1 /FVC was found, while milk-type had variable influence and significance. Taken together, we found certain milk consumption tendencies were associated with pulmonary function values among normal and asthmatic populations. These findings propound future investigations into the potential role of dairy consumption in altering lung function and asthma outcomes, with potential impact on the protection and maintenance of pulmonary health.

As countries continue to industrialize, major cities experience diminished air quality, whereas rural populations also experience poor air quality from sources such as agricultural operations. These exposures to environmental pollution from both rural and populated/industrialized sources have adverse effects on human health. Although respiratory diseases (e.g., asthma and chronic obstructive pulmonary disease) are the most commonly reported following long-term exposure to particulate matter and hazardous chemicals, gastrointestinal complications have also been associated with the increased risk of lung disease from inhalation of polluted air. The interconnectedness of these organ systems has offered valuable insights into the roles of the immune system and the micro/mycobiota as mediators of communication between the lung and the gut during disease states. A topical example of this relationship is provided by reports of multiple gastrointestinal symptoms in patients with coronavirus disease 2019 (COVID-19), whereas the rapid transmission and increased risk of COVID-19 has been linked to poor air quality and high levels of particulate matter. In this review, we focus on the mechanistic effects of environmental pollution on disease progression with special emphasis on the gut-lung axis.

Purpose of Review: Lung diseases such as asthma and COPD are major public health issues and related to occupational exposures. While therapies to limit the development and progression of these diseases are limited, nutrition interventions could offer potential alternatives to mediate the inflammation associated with these diseases. This is a narrative review of the current state of relevant nutrients on inflammation and respiratory outcomes associated with occupational exposures., Recent Findings: Relevant nutrients that have been investigated in recent years include omega-3 polyunsaturated fatty acids, zinc, vitamin D, dairy products, and antioxidants. These nutrients have demonstrated the potential to prevent or modify the adverse outcomes associated with occupational exposures, primarily in preclinical studies. Current therapies for respiratory consequences associated with occupational exposures are limited; therefore, addressing strategies for reducing inflammation is important in improving quality of life and limiting health care costs. More human studies are warranted to determine the effectiveness of nutrition as an intervention.

Polyunsaturated fatty acids (PUFAs) are essential for fetal development, and intrauterine transfer is the only supply of PUFAs to the fetus. The prevailing theory of gestational nutrient transfer is that certain nutrients (including PUFAs) may have prioritized transport across the placenta. Numerous studies have identified correlations between maternal and infant fatty acid concentrations; however, little is known about what role maternal PUFA status may play in differential intrauterine nutrient transfer. Twenty mother-infant dyads were enrolled at delivery for collection of maternal and umbilical cord blood, and placental tissue samples. Plasma concentrations of PUFAs were assessed using gas chromatography (GC-FID). Intrauterine transfer percentages for each fatty acid were calculated as follows: ((cord blood fatty acid level/maternal blood fatty acid level) × 100). Kruskal-Wallis tests were used to compare transfer percentages between maternal fatty acid tertile groups. A p -value < 0.05 was considered significant. There were statistically significant differences in intrauterine transfer percentages of arachidonic acid (AA) (64% vs. 65% vs. 45%, p = 0.02), eicosapentaenoic acid (EPA) (41% vs. 19% vs. 17%, p = 0.03), and total fatty acids (TFA) (27% vs. 26% vs. 20%, p = 0.05) between maternal plasma fatty acid tertiles. Intrauterine transfer percentages of AA, EPA, and TFA were highest in the lowest tertile of respective maternal fatty acid concentration. These findings may indicate that fatty acid transfer to the fetus is prioritized during gestation even during periods of maternal nutritional inadequacy.

Dimethyl selenide (DMSe) is one of the major volatile organoselenium compounds released into the atmosphere through plant metabolism and microbial methylation. DMSe has been recently revealed as a precursor of secondary organic aerosol (SOA), and its resultant SOA possesses strong oxidizing capability toward thiol groups that can perturb several major biological pathways in human airway epithelial cells and is linked to genotoxicity, DNA damage, and p53-mediated stress responses. Mounting evidence has suggested that long noncoding RNAs (lncRNAs) are involved in stress responses to internal and environmental stimuli. However, the underlying molecular interactions remain to be elucidated. In this study, we performed integrative analyses of lncRNA-mRNA coexpression in the transformed human bronchial epithelial BEAS-2B cell line exposed to DMSe-derived SOA. We identified a total of 971 differentially expressed lncRNAs in BEAS-2B cells exposed to SOA derived from O 3 and OH oxidation of DMSe. Gene ontology (GO) network analysis of cis -targeted genes showed significant enrichment of DNA damage, apoptosis, and p53-mediated stress response pathways. trans -Acting lncRNAs, including PINCR , PICART1 , DLGAP1-AS2 , and LINC01629 , known to be associated with human carcinogenesis, also showed altered expression in cell treated with DMSe-SOA. Overall, this study highlights the regulatory role of lncRNAs in altered gene expression induced by DMSe-SOA exposure.

Chronic obstructive pulmonary disease (COPD) is a lung disorder characterized by progressive airflow obstruction associated with inflammation and emphysema, and it is currently one of the leading causes of death worldwide. Recent studies with genetically engineered mice reported that during pulmonary inflammation, basophil-derived interleukin-4 can act on lung-infiltrating monocytes causing aberrant expression of the matrix metalloproteinase-12 (MMP-12). MMP-12 activity in turn causes the destruction of alveolar walls leading to emphysema, making it potentially a valid target for pharmacological intervention. Using nuclear magnetic resonance (NMR)- and structure-based optimizations, the current study reports on the optimized novel, potent, and selective MMP-12 inhibitors with single-digit nanomolar affinity in vitro and in vivo efficacy. Using a murine model of elastase-induced emphysema we demonstrated that the most potent agents exhibited a significant decrease in emphysema-like pathology compared to vehicle-treated mice, thus suggesting that the reported agents may potentially be translated into novel therapeutics for the treatment of COPD.

Asthma, emphysema, COVID-19 and other lung-impacting diseases cause the remodeling of tissue structural properties and can lead to changes in conducting pulmonary volume, viscoelasticity, and air flow distribution. Whole organ experimental inflation tests are commonly used to understand the impact of these modifications on lung mechanics. Here we introduce a novel, automated, custom-designed device for measuring the volume and pressure response of lungs, surpassing the capabilities of traditional machines and built to range size-scales to accommodate both murine and porcine tests. The software-controlled system is capable of constructing standardized continuous volume-pressure curves, while accounting for air compressibility, yielding consistent and reproducible measures while eliminating the need for pulmonary degassing. This device uses volume-control to enable viscoelastic whole lung macromechanical insights from rate dependencies and pressure-time curves. Moreover, the conceptual design of this device facilitates studies relating the phenomenon of diaphragm breathing and artificial ventilation induced by pushing air inside the lungs. System capabilities are demonstrated and validated via a comparative study between ex vivo murine lungs and elastic balloons, using various testing protocols. Volume-pressure curve comparisons with previous pressure-controlled systems yield good agreement, confirming accuracy. This work expands the capabilities of current lung experiments, improving scientific investigations of healthy and diseased pulmonary biomechanics. Ultimately, the methodologies demonstrated in the manufacturing of this system enable future studies centered on investigating viscoelasticity as a potential biomarker and improvements to patient ventilators based on direct assessment and comparisons of positive- and negative-pressure mechanics., (Copyright © 2020 Sattari, Mariano, Vittalbabu, Velazquez, Postma, Horst, Teh, Nordgren and Eskandari.)

Preterm birth is a leading cause of child morbidity and mortality, so strategies to reduce early birth must remain a priority. One key approach to enhancing birth outcomes is improving maternal dietary intake. Therefore, the purpose of this review is to discuss mechanisms on perinatal status of fat-soluble nutrients (carotenoids, retinol, tocopherols) and omega-3 fatty acids and how they impact risk for preterm birth. Literature review demonstrates that maternal dietary intake and biological (blood and placental tissue) levels of fat-soluble nutrients during pregnancy may provide antioxidative, anti-inflammatory, and immunomodulatory health benefits. Omega-3 fatty acids also promote increased production of specialized pro-resolving mediators, subsequently mediating inflammation resolution. Combined effects of these nutrients support appropriate placental organogenesis and function. Consequently, fat-soluble nutrients and omega-3 fatty acids serve as strong influencers for preterm birth risk. As dietary intake remains a modifiable factor, future intervention would benefit from a focus on optimizing perinatal status of these specific nutrients., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Agricultural workers are at risk for the development of acute and chronic lung diseases due to their exposure to organic agricultural dusts. A diet intervention using the omega-3 fatty acid docosahexaenoic acid (DHA) has been shown to be an effective therapeutic approach for alleviating a dust-induced inflammatory response. We thus hypothesized a high-DHA diet would alter the dust-induced inflammatory response through the increased production of specialized pro-resolving mediators (SPMs). Mice were pre-treated with a DHA-rich diet 4 weeks before being intranasally challenged with a single dose of an extract made from dust collected from a concentrated swine feeding operation (HDE). This omega-3-fatty-acid-rich diet led to reduced arachidonic acid levels in the blood, enhanced macrophage recruitment, and increased the production of the DHA-derived SPM Resolvin D1 (RvD1) in the lung following HDE exposure. An assessment of transcript-level changes in the immune response demonstrated significant differences in immune pathway activation and alterations of numerous macrophage-associated genes among HDE-challenged mice fed a high DHA diet. Our data indicate that consuming a DHA-rich diet leads to the enhanced production of SPMs during an acute inflammatory challenge to dust, supporting a role for dietary DHA supplementation as a potential therapeutic strategy for reducing dust-induced lung inflammation.

Until recently, data supporting the tissue-resident status of mesenchymal stromal cells (MSC) has been ambiguous since their discovery in the 1950-60s. These progenitor cells were first discovered as bone marrow-derived adult multipotent cells and believed to migrate to sites of injury, opposing the notion that they are residents of all tissue types. In recent years, however, it has been demonstrated that MSC can be found in all tissues and MSC from different tissues represent distinct populations with differential protein expression unique to each tissue type. Importantly, these cells are efficient mediators of tissue repair, regeneration, and prove to be targets for therapeutics, demonstrated by clinical trials ( phase 1 - 4 ) for MSC-derived therapies for diseases like graft-versus-host-disease, multiple sclerosis, rheumatoid arthritis, and Crohn's disease. The tissue-resident status of MSC found in the lung is a key feature of their importance in the context of disease and injuries of the respiratory system, since these cells could be instrumental to providing more specific and targeted therapies. Currently, bone marrow-derived MSC have been established in the treatment of disease, including diseases of the lung. However, with lung-resident MSC representing a unique population with a different phenotypic and gene expression pattern than MSC derived from other tissues, their role in remediating lung inflammation and injury could provide enhanced efficacy over bone marrow-derived MSC methods. Through this review, lung-resident MSC will be characterized, using previously published data, by surface markers, gene expression patterns, and compared with bone-marrow MSC to highlight similarities and, importantly, differences in these cell types.

Although there are many recognized health benefits for the consumption of omega-3 (n-3) long-chain polyunsaturated fatty acids (LCPUFA), intake in the United States remains below recommended amounts. This analysis was designed to provide an updated assessment of fish and n-3 LCPUFA intake (eicosapentaenoic (EPA), docosahexaenoic acid (DHA), and EPA+DHA) in the United States adult population, based on education, income, and race/ethnicity, using data from the 2003-2014 National Health and Nutrition Examination Survey (NHANES) ( n = 44,585). Over this survey period, participants with less education and lower income had significantly lower n-3 LCPUFA intakes and fish intakes ( p < 0.001 for all between group comparisons). N-3 LCPUFA intake differed significantly according to ethnicity ( p < 0.001), with the highest intake of n-3 LCPUFA and fish in individuals in the "Other" category (including Asian Americans). Supplement use increased EPA + DHA intake, but only 7.4% of individuals consistently took supplements. Overall, n-3 LCPUFA intake in this study population was low, but our findings indicate that individuals with lower educational attainment and income are at even higher risk of lower n-3 LCPUFA and fish intake.

Exposure to agricultural bioaerosols can lead to chronic inflammatory lung diseases. Amphiregulin (AREG) can promote the lung repair process but can also lead to fibrotic remodeling. The objective of this study was to determine the role of AREG in altering recovery from environmental dust exposure in a murine in vivo model and in vitro using cultured human and murine lung fibroblasts. C57BL/6 mice were intranasally exposed to swine confinement facility dust extract (DE) or saline daily for 1 wk or allowed to recover for 3-7 days while being treated with an AREG-neutralizing antibody or recombinant AREG. Treatment with the anti-AREG antibody prevented resolution of DE exposure-induced airway influx of total cells, neutrophils, and macrophages and increased levels of TNF-α, IL-6, and CXCL1. Neutrophils and activated macrophages (CD11c + CD11b hi ) persisted after recovery in lung tissues of anti-AREG-treated mice. In murine and human lung fibroblasts, DE induced the release of AREG and inflammatory cytokines. Fibroblast recellularization of primary human lung mesenchymal matrix scaffolds and wound closure was inhibited by DE and enhanced with recombinant AREG alone. AREG treatment rescued the DE-induced inhibitory fibroblast effects. AREG intranasal treatment for 3 days during recovery phase reduced repetitive DE-induced airway inflammatory cell influx and cytokine release. Collectively, these studies demonstrate that inhibition of AREG reduced, whereas AREG supplementation promoted, the airway inflammatory recovery response following environmental bioaerosol exposure, and AREG enhanced fibroblast function, suggesting that AREG could be targeted in agricultural workers repetitively exposed to organic dust environments to potentially prevent and/or reduce disease.

Dimethyl selenide (DMSe) is one of the major volatile organoselenium compounds released from aquatic and terrestrial environments through microbial transformation and plant metabolism. The detailed processes of DMSe leading to secondary organic aerosol (SOA) formation and the pulmonary health effects induced by inhalation of DMSe-derived SOA remain largely unknown. In this study, we characterized the chemical composition and formation yields of SOA produced from the oxidation of DMSe with OH radicals and O 3 in controlled chamber experiments. Further, we profiled the transcriptome-wide gene expression changes in human airway epithelial cells (BEAS-2B) after exposure to DMSe-derived SOA. Our analyses indicated a significantly higher SOA yield resulting from the OH-initiated oxidation of DMSe. The oxidative potential of DMSe-derived SOA, as measured by the dithiothreitol (DTT) assay, suggested the presence of oxidizing moieties in DMSe-derived SOA at levels higher than typical ambient aerosols. Utilizing RNA sequencing (RNA-Seq) techniques, gene expression profiling followed by pathway enrichment analysis revealed several major biological pathways perturbed by DMSe-derived SOA, including elevated genotoxicity, DNA damage, and p53-mediated stress responses, as well as downregulated cholesterol biosynthesis, glycolysis, and interleukin IL-4/IL-13 signaling. This study highlights the significance of DMSe-derived SOA as a stressor in human airway epithelial cells.

Breathing involves fluid-solid interactions in the lung; however, the lack of experimental data inhibits combining the mechanics of air flow to airway deformation, challenging the understanding of how biomaterial constituents contribute to tissue response. As such, lung mechanics research is increasingly focused on exploring the relationship between structure and function. To address these needs, we characterize mechanical properties of porcine airways using uniaxial tensile experiments, accounting for bronchial orientation- and location- dependency. Structurally-reinforced constitutive models are developed to incorporate the role of collagen and elastin fibers embedded within the extrafibrillar matrix. The strain-energy function combines a matrix description (evaluating six models: compressible NeoHookean, unconstrained Ogden, uncoupled Mooney-Rivlin, incompressible Ogden, incompressible Demiray and incompressible NeoHookean), superimposed with non-linear fibers (evaluating two models: exponential and polynomial). The best constitutive formulation representative of all bronchial regions is determined based on curve-fit results to experimental data, accounting for uniqueness and sensitivity. Glycosaminoglycan and collagen composition, alongside tissue architecture, indicate fiber form to be primarily responsible for observed airway anisotropy and heterogeneous mechanical behavior. To the authors' best knowledge, this study is the first to formulate a structurally-motivated constitutive model, augmented with biochemical analysis and microstructural observations, to investigate the mechanical function of proximal and distal bronchi. Our systematic pulmonary tissue characterization provides a necessary foundation for understanding pulmonary mechanics; furthermore, these results enable clinical translation through simulations of airway obstruction in disease, fluid-structure interaction insights during breathing, and potentially, predictive capabilities for medical interventions. STATEMENT OF SIGNIFICANCE: The advancement of pulmonary research relies on investigating the biomechanical response of the bronchial tree. Experiments demonstrating the non-linear, heterogeneous, and anisotropic material behavior of porcine airways are used to develop a structural constitutive model representative of proximal and distal bronchial behavior. Calibrated material parameters exhibit regional variation in biomaterial properties, initially hypothesized to originate from tissue constituents. Further exploration through biochemical and histological analysis indicates mechanical function is primarily governed by microstructural form. The results of this study can be directly used in finite element and fluid-structure interaction models to enable physiologically relevant and more accurate computational simulations aimed to help diagnose and monitor pulmonary disease., (Copyright © 2019. Published by Elsevier Ltd.)

Omega-3 fatty acids are important to pregnancy and neonatal development and health. One mechanism by which omega-3 fatty acids exert their protective effects is through serving as substrates for the generation of specialized pro-resolving lipid mediators (SPM) that potently limit and resolve inflammatory processes. We recently identified that SPM levels are increased in maternal blood at delivery as compared to umbilical cord blood, suggesting the placenta as a potential site of action for maternal SPM. To explore this hypothesis, we obtained human placental samples and stained for the SPM resolvin D2 (RvD2) receptor GPR18 via immunohistochemistry. In so doing, we identified GPR18 expression in placental vascular smooth muscle and extravillous trophoblasts of the placental tissues. Using in vitro culturing, we confirmed expression of GPR18 in these cell types and further identified that stimulation with RvD2 led to significantly altered responsiveness (cytoskeletal changes and pro-inflammatory cytokine production) to lipopolysaccharide inflammatory stimulation in human umbilical artery smooth muscle cells and placental trophoblasts. Taken together, these findings establish a role for SPM actions in human placental tissue.

The long-chain n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play a crucial role in health, but previous National Health and Nutrition Examination Survey (NHANES) analyses have shown that EPA and DHA intake in the United States is far below recommendations (~250-500 mg/day EPA + DHA). Less is known about docosapentaenoic acid (DPA), the metabolic intermediate of EPA and DHA; however, evidence suggests DPA may be an important contributor to long-chain n-3 fatty acid intake and impart unique benefits. We used NHANES 2003-2014 data (n = 45,347) to assess DPA intake and plasma concentrations, as well as the relationship between intake and plasma concentrations of EPA, DPA, and DHA. Mean DPA intake was 22.3 ± 0.8 mg/day from 2013 to 2014, and increased significantly over time (p < 0.001), with the lowest values from 2003 to 2004 (16.2 ± 1.2 mg/day). DPA intake was higher in adults (20-55 years) and seniors (55+ years) compared to younger individuals. In regression analyses, DPA intake was a significant predictor of plasma EPA (β = 138.5; p < 0.001) and DHA (β = 318.9; p < 0.001). Plasma DPA was predicted by EPA and DHA intake (β = 13.15; p = 0.001 and β = 7.4; p = 0.002), but not dietary DPA (p = 0.3). This indicates that DPA intake is not a good marker of plasma DPA status (or vice versa), and further research is needed to understand the factors that affect the interconversion of EPA and DPA. These findings have implications for future long-chain n-3 fatty acids dietary recommendations., (© 2019 AOCS.)

Air pollution poses a significant threat to the environment and human health. Most in vivo health studies conducted regarding air pollutants, including particulate matter (PM) and gas phase pollutants, have been either through traditional medical intranasal treatment or using a tiny chamber, which limit animal activities. In this study, we designed and tested a large, whole-body, multiple animal exposure chamber with uniform dispersion and exposure stability for animal studies. The chamber simultaneously controls particle size distribution and PM mass concentration. Two different methods were used to generate aerosol suspension through either soluble material (Alternaria extract), liquid particle suspension (nanosilica solution), or dry powder (silica powder). We demonstrate that the chamber system provides well controlled and characterized whole animal exposures, where dosage is by inhalation of particulate matter.

Nutritional status is a well-recognized prognostic indicator in chronic obstructive pulmonary disease (COPD); however, very little is known about the relationship between lung function and saturated fat intake. We used data from the cross-sectional National Health and Nutrition Examination Surveys (NHANES) to assess the relationship between saturated fatty acid (SFA) intake and lung function in the general US adult population. Adults in NHANES (2007⁻2012) with pre-bronchodilator spirometry measurements and dietary SFA intake were included. Primary outcomes were lung function including forced expiratory volume in one second (FEV₁) , FEV₁, forced vital capacity (FVC), FEV₁/FVC ratio, percent predicted FEV₁ and percent predicted FVC. Multivariable regression models in the general population as well as those with spirometry-defined airflow obstruction were used to assess the relationship between lung function measurements and dietary SFA intake after adjustment for confounders. 11,180 eligible participants were included in this study. Univariate analysis revealed a statistically significant positive association between total SFA intake and lung function outcomes; however, these relationships were attenuated after adjustment for covariates. A secondary analysis of individuals with spirometry-defined airflow obstruction (FEV₁/FVC < 0.7) revealed that a lower intake of SFA was associated with reduced FEV 1 (β = -126.4, p = 0.04 for quartile 1 vs. quartile 4), FVC (β = -165.8. p = 0.01 for quartile 1 vs. quartile 4), and percent predicted FVC (β = -3.3. p = 0.04 for quartile 1 vs. quartile 4), after adjustment for relevant confounders. No associations were observed for the FEV₁/FVC ratio and percent predicted FEV₁. It is possible that characteristics such as food source and fatty acid chain length may influence associations between saturated fatty acid intake and health outcomes., Competing Interests: The authors declare no conflict of interest.

Occupational agricultural dust exposure can cause severe lung injury, including COPD and asthma exacerbations. Cell-derived extracellular vesicles can mediate inflammatory responses and immune activation, but the contribution of diet-derived extracellular vesicles to these processes is poorly understood. We investigated whether bovine milk-derived extracellular vesicles modulate inflammatory responses to agricultural dust exposures in a murine model. C57BL/6 mice were fed either an extracellular vesicle-enriched modification of the AIN-93G diet with lyophilized bovine milk (EV) or a control diet wherein the milk was presonicated, disrupting the milk extracellular vesicles and thereby leading to RNA degradation (DEV). Mice were maintained on the diets for 5-7 weeks and challenged with a single (acute) intranasal instillation of a 12.5% organic dust extract (DE) or with 15 instillations over 3 weeks (repetitive exposure model). Through these investigations, we identified significant interactions between diet and DE when considering numerous inflammatory outcomes, including lavage inflammatory cytokine levels and cellular infiltration into the lung airways. DE-treated peritoneal macrophages also demonstrated altered polarization, with EV-fed mouse macrophages exhibiting an M1 shift compared to an M2 phenotype in DEV-fed mice (IL-6, TNF, IL-12/23 all significantly elevated, and IL-10 and arginase decreased in EV macrophages, ex vivo). In complementary in vitro studies, mouse macrophages treated with purified milk-derived EV were found to express similar polarization phenotypes upon DE stimulation. These results suggest a role for dietary extracellular vesicles in the modulation of lung inflammation in response to organic dust which may involve macrophage phenotype polarization., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Despite the importance of n-3 fatty acids for health, intakes remain below recommended levels. The objective of this study was to provide an updated assessment of fish and n-3 fatty acid intake (i.e., eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and EPA+DHA) in the United States using the 2003⁻2014 National Health and Nutrition Examination Survey (NHANES) data ( n = 45,347)). Over this survey period, toddlers, children, and adolescents (aged 1⁻19) had significantly lower n-3 fatty acid intake ( p < 0.001) compared to adults and seniors, which remained significant after adjusting for caloric intake. Females demonstrated lower n-3 fatty acid intake than males ( p < 0.001), with adult and senior women having significantly lower intakes compared to men in the same age categories ( p < 0.001) after adjustment for energy intake. Women also consumed less fish than men (5.8 versus 6.1 servings/month, p < 0.001). The estimated intakes of n-3 fatty acids in pregnant women did not differ from non-pregnant women ( p = 0.6 for EPA+DHA), although pregnant women reported consuming less high n-3 fatty acid-containing fish than non-pregnant women (1.8 versus 2.6 servings/month, p < 0.001). Our findings indicate that subgroups of the population may be at higher risk of n-3 fatty acid intakes below recommended levels.

Omega (n)-3 fatty acids are vital to neonatal maturation, and recent investigations reveal n-3 fatty acids serve as substrates for the biosynthesis of specialized pro-resolving lipid mediators (SPM) that have anti-inflammatory and immune-stimulating effects. The role SPM play in the protection against negative maternal-fetal health outcomes is unclear, and there are no current biomarkers of n-3 fatty acid sufficiency. We sought to ascertain the relationships between n-3 fatty acid intake, SPM levels, and maternal-fetal health outcomes. We obtained n-3 fatty acid intake information from 136 mothers admitted for delivery using a food frequency questionnaire and measured docosahexaenoic acid (DHA)-derived SPMs resolvin D1 (RvD1) and RvD2 in maternal and cord plasma. We found significantly elevated SPM in maternal versus cord plasma, and increased SPM levels were associated with at-risk outcomes. We also identified that increased DHA intake was associated with elevated maternal plasma RvD1 ( p = 0.03; R² = 0.18) and RvD2 ( p = 0.04; R² = 0.20) in the setting of neonatal intensive care unit (NICU) admission. These findings indicate that increased n-3 fatty acid intake may provide increased substrate for the production of SPM during high-risk pregnancy/delivery conditions, and that increased maternal plasma SPM could serve as a biomarker for negative neonatal outcomes.

Purpose of Review: Agriculture environments contain a variety of inflammatory aerosols that may increase risk for lung inflammation and disease in exposed individuals. In addition, epidemiological studies have also identified protective effects of rural environments and farming exposures., Recent Findings: In this review, we will discuss recent literature published since 2016 that investigates the impact of differing agricultural exposures on respiratory health. Discussions include the impact of farming modernization, education, and personal protective equipment usage among workers, timing and duration in mediating lung health outcomes, and population studies investigating the association between exposure and risk for numerous lung diseases.

Agricultural organic dust exposures trigger harmful airway inflammation, and workers experiencing repetitive dust exposures are at increased risk for lung disease. Mesenchymal stem/stromal cells (MSCs) regulate wound repair processes in the lung, and may contribute to either proresolution or -fibrotic lung responses. It is unknown how organic dust exposures alter lung-resident MSC activation and proinflammatory versus prorepair programs in the lung. To address this gap in knowledge, we isolated human lung-resident MSC from lung tissue. Cells were stimulated with aqueous extracts of organic dusts (DE) derived from swine confinement facilities and were assessed for changes in proliferative and migratory capacities, and production of proinflammatory and prorepair mediators. Through these investigations, we found that DE induces significant release of proinflammatory mediators TNF-α, IL-6, IL-8, and matrix metalloproteases, while also inducing the production of prorepair mediators amphiregulin, FGF-10, and resolvin D1. In addition, DE significantly reduced the growth and migratory capacities of lung-resident MSC. Together, these investigations indicate lung-resident MSC activation and wound repair activities are altered by organic dust exposures. These findings warrant future investigations to assess how organic dusts affect lung-resident mesenchymal stem/stromal cell function and impact airway inflammation, injury, and repair during agricultural aerosol exposures.

Injurious dust exposures in the agricultural workplace involve the release of inflammatory mediators and activation of epidermal growth factor receptor (EGFR) in the respiratory epithelium. Amphiregulin (AREG), an EGFR ligand, mediates tissue repair and wound healing in the lung epithelium. Omega-3 fatty acids such as docosahexaenoic acid (DHA) are also known modulators of repair and resolution of inflammatory injury. This study investigated how AREG, DHA, and EGFR modulate lung repair processes following dust-induced injury. Primary human bronchial epithelial (BEC) and BEAS-2B cells were treated with an aqueous extract of swine confinement facility dust (DE) in the presence of DHA and AREG or EGFR inhibitors. Mice were exposed to DE intranasally with or without EGFR inhibition and DHA. Using a decellularized lung scaffolding tissue repair model, BEC recolonization of human lung scaffolds was analyzed in the context of DE, DHA, and AREG treatments. Through these investigations, we identified an important role for AREG in mediating BEC repair processes. DE-induced AREG release from BEC, and DHA treatment following DE exposure, enhanced this release. Both DHA and AREG also enhanced BEC repair capacities and rescued DE-induced recellularization deficits. In vivo, DHA treatment enhanced AREG production following DE exposure, whereas EGFR inhibitor-treated mice exhibited reduced AREG in their lung homogenates. These data indicate a role for AREG in the process of tissue repair after inflammatory lung injury caused by environmental dust exposure and implicate a role for DHA in regulating AREG-mediated repair signaling in BEC.

Continuous exposure to aerosolized fine (particle size ≤2.5 µm) and ultrafine (particle size ≤0.1 µm) particulates can trigger innate inflammatory responses in the lung and brain depending on particle composition. Most studies of manmade toxicants use inhalation exposure routes, whereas most studies of allergens use soluble solutions administered via intranasal or injection routes. Here, we tested whether continuous inhalation exposure to aerosolized Alternaria alternata particulates (a common fungal allergen associated with asthma) would induce innate inflammatory responses in the lung and brain. By designing a new environmental chamber able to control particle size distribution and mass concentration, we continuously exposed adult mice to aerosolized ultrafine Alternaria particulates for 96 hr. Despite induction of innate immune responses in the lung, induction of innate immune responses in whole brain samples was not detected by quantitative polymerase chain reaction or flow cytometry. However, exposure did trigger decreases in Arginase 1, inducible nitric oxide synthase, and tumor necrosis factor alpha mRNA in the brainstem samples containing the central nervous system respiratory circuit (the dorsal respiratory group, ventral respiratory group, and the pre-Bötzinger and Bötzinger complexes). In addition, a significant decrease in the percentage of Toll-like receptor 2-expressing brainstem microglia was detected by flow cytometry. Histologic analysis revealed a significant decrease in Iba1 but not glial fibrillary acidic protein immunoreactivity in both the brainstem and the hippocampus. Together these data indicate that inhalation exposure to a natural fungal allergen under conditions sufficient to induce lung inflammation surprisingly causes reductions in baseline expression of select innate immune molecules (similar to that observed during endotoxin tolerance) in the region of the central nervous system controlling respiration.

Infants developing in a pro-inflammatory intrauterine environment have a significant risk for severe complications after birth. It has been shown that omega-3 fatty acids reduce inflammation, and also reduce early preterm births and decrease risk of infant admission to the neonatal intensive care unit. However, the mechanism for omega-3 fatty acids exerting these effects was previously unknown. Recent evidence has shown that downstream products of polyunsaturated fatty acids called specialized pro-resolving mediators may mediate inflammatory physiology, thus playing an important role in maternal-fetal health. In this review, current knowledge relating to specialized pro-resolving mediators in pregnancy, delivery, and perinatal disease states will be summarized., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

We sought to determine whether a combination of purified n-3 fatty acids (n-3) and SC-560 (SC), a cyclooxygenase-1-specific inhibitor, is effective in ameliorating nonalcoholic fatty liver disease in obesity. Female wild-type mice were fed a high-fat and high-cholesterol diet (HF) supplemented with n-3 in the presence or absence of SC. Mice treated with SC alone exhibited no change in liver lipids, whereas n-3-fed mice tended to have lower hepatic lipids. Mice given n-3+SC had significantly lower liver lipids compared with HF controls indicating enhanced lipid clearance. Total and sulfated bile acids were significantly higher only in n-3+SC-treated mice compared with chow diet (CD) controls. Regarding mechanisms, the level of pregnane X receptor (PXR), a nuclear receptor regulating drug/bile detoxification, was significantly higher in mice given n-3 or n-3+SC. Studies in precision-cut liver slices and in cultured hepatoma cells showed that n-3+SC enhanced not only the expression/activation of PXR and its target genes but also the expression of farnesoid X receptor (FXR), another regulator of bile synthesis/clearance, indicating that n-3+SC can induce both PXR and FXR. The mRNA level of FGFR4 which inhibits bile formation showed a significant reduction in Huh 7 cells upon n-3 and n-3+SC treatment. PXR overexpression in hepatoma cells confirmed that n-3 or SC each induced the expression of PXR target genes and in combination had an enhanced effect. Our findings suggest that combining SC with n-3 potentiates its lipid-lowering effect, in part, by enhanced PXR and/or altered FXR/FGFR4 signaling., (Copyright © 2017 Elsevier Inc. All rights reserved.)