Heated tobacco product IQOS induces unique metabolic signatures in human bronchial epithelial cells

Metabolic signatures are lacking for heated tobacco products, making it crucial to identify new biosignatures of lung damage. This will enable the establishment of product-specific guidelines and an understanding of associated toxicity. https://bit.ly/3TkhBox.

Early Childhood Caries and Dental Care Utilization in Mangalore, India: Parents' Perceptions

BACKGROUND

Parents often underuse dental care services for their children with early childhood caries (ECC), resulting in a high burden of untreated dental caries.

AIM

To describe parental perceptions and challenges in dental care utilization for their children with ECC.

DESIGN

A descriptive qualitative study was conducted with parents of children with ECC seeking dental care in Mangalore, India. Data were collected through focus group discussions using an interview guide. Manual line-by-line coding and content analysis methods were used for data analysis.

RESULTS

Three categories were generated from data obtained through 5 focus groups of 27 participants: dental care visiting patterns, the significance of dental visits, and challenges to dental care utilization. Parents would only visit the dentist when they perceived their children's tooth problems. The challenges faced include time constraints, misinformation, lack of awareness and motivation, costs, fear, and anxiety of the children and the parents themselves. Parents perceived improvements in the awareness of their children's oral health and quality of life after dental visits.

CONCLUSION

Attending dental services to treat their children's tooth problems was the primary way of attaining awareness about prevention among the parents of children with ECC. Increased oral health awareness and improved quality of life can motivate parents to seek further dental care for their children. Collaboration with multidisciplinary stakeholders is required to improve oral health awareness among parents of children with ECC.

KNOWLEDGE TRANSFER STATEMENT

The study's results will help plan targeted preventive programs for children with ECC. The study suggests dental care utilization by children with ECC is based on parental perceptions of their children's tooth problems. It outlines the challenges that affect dental visits of children with ECC and the role of multidisciplinary stakeholders. Improved oral health awareness and quality of life following dental treatment can facilitate further dental visits.

Prorelaxant E-type Prostanoid Receptors Functionally Partition to Different Procontractile Receptors in Airway Smooth Muscle

Prostaglandin E2 imparts diverse physiological effects on multiple airway cells through its actions on four distinct E-type prostanoid (EP) receptor subtypes (EP1-EP4). Gs-coupled EP2 and EP4 receptors are expressed on airway smooth muscle (ASM), yet their capacity to regulate the ASM contractile state remains subject to debate. We used EP2 and EP4 subtype-specific agonists (ONO-259 and ONO-329, respectively) in cell- and tissue-based models of human ASM contraction-magnetic twisting cytometry (MTC), and precision-cut lung slices (PCLSs), respectively-to study the EP2 and EP4 regulation of ASM contraction and signaling under conditions of histamine or methacholine (MCh) stimulation. ONO-329 was superior (<0.05) to ONO-259 in relaxing MCh-contracted PCLSs (log half maximal effective concentration [logEC50]: 4.9 × 10-7 vs. 2.2 × 10-6; maximal bronchodilation ± SE, 35 ± 2% vs. 15 ± 2%). However, ONO-259 and ONO-329 were similarly efficacious in relaxing histamine-contracted PCLSs. Similar differential effects were observed in MTC studies. Signaling analyses revealed only modest differences in ONO-329- and ONO-259-induced phosphorylation of the protein kinase A substrates VASP and HSP20, with concomitant stimulation with MCh or histamine. Conversely, ONO-259 failed to inhibit MCh-induced phosphorylation of the regulatory myosin light chain (pMLC20) and the F-actin/G-actin ratio (F/G-actin ratio) while effectively inhibiting their induction by histamine. ONO-329 was effective in reversing induced pMLC20 and the F/G-actin ratio with both MCh and histamine. Thus, the contractile-agonist-dependent differential effects are not explained by changes in the global levels of phosphorylated protein kinase A substrates but are reflected in the regulation of pMLC20 (cross-bridge cycling) and F/G-actin ratio (actin cytoskeleton integrity, force transmission), implicating a role for compartmentalized signaling involving muscarinic, histamine, and EP receptor subtypes.

Epicutaneous Sensitization to the Phytocannabinoid β-Caryophyllene Induces Pruritic Inflammation

In recent years, there has been increased accessibility to cannabis for recreational and medicinal use. Incidentally, there has been an increase in reports describing allergic reactions to cannabis including exacerbation of underlying asthma. Recently, multiple protein allergens were discovered in cannabis, yet these fail to explain allergic sensitization in many patients, particularly urticaria and angioedema. Cannabis has a rich chemical profile including cannabinoids and terpenes that possess immunomodulatory potential. We examined whether major cannabinoids of cannabis such as cannabidiol (CBD) and the bicyclic sesquiterpene beta-caryophyllene (β-CP) act as contact sensitizers. The repeated topical application of mice skin with β-CP at 10 mg/mL (50 µL) induced an itch response and dermatitis at 2 weeks in mice, which were sustained for the period of study. Histopathological analysis of skin tissues revealed significant edema and desquamation for β-CP at 10 mg/mL. For CBD and β-CP, we observed a dose-dependent increase in epidermal thickening with profound thickening observed for β-CP at 10 mg/mL. Significant trafficking of CD11b cells was observed in various compartments of the skin in response to treatment with β-CP in a concentration-dependent manner. Mast cell trafficking was restricted to β-CP (10 mg/mL). Mouse proteome profiler cytokine/chemokine array revealed upregulation of complement C5/5a (anaphylatoxin), soluble intracellular adhesion molecule-1 (sICAM-1) and IL-1 receptor antagonist (IL-1RA) in animals dosed with β-CP (10 mg/mL). Moreover, we observed a dose-dependent increase in serum IgE in animals dosed with β-CP. Treatment with β-CP (10 mg/mL) significantly reduced filaggrin expression, an indicator of barrier disruption. In contrast, treatment with CBD at all concentrations failed to evoke scratching and dermatitis in mice and did not result in increased serum IgE. Further, skin tissues were devoid of any remarkable features, although at 10 mg/mL CBD we did observe the accumulation of dermal CD11b cells in skin tissue sections. We also observed increased filaggrin staining in mice repeatedly dosed with CBD (10 mg/mL). Collectively, our studies indicate that repeated exposure to high concentrations of β-CP can induce dermatitis-like pathological outcomes in mice.

Proteomics-Based Approach for Detailing the Allergenic Profile of Cannabis Chemotypes

Allergic sensitization to cannabis is an emerging public health concern and is difficult to clinically establish owing to lack of standardized diagnostic approaches. Attempts to develop diagnostic tools were largely hampered by the Schedule I restrictions on cannabis, which limited accessibility for research. Recently, however, hemp was removed from the classified list, and increased accessibility to hemp allows for the evaluation of its practical clinical value for allergy diagnosis. We hypothesized that the proteomic profile is preserved across different cannabis chemotypes and that hemp would be an ideal source of plant material for clinical testing. Using a proteomics-based approach, we examined whether distinct varieties of cannabis plant contain relevant allergens of cannabis. Cannabis extracts were generated from high tetrahydrocannabinol variety (Mx), high cannabidiol variety (V1-19) and mixed profile variety (B5) using a Plant Total Protein Extraction Kit. Hemp extracts were generated using other standardized methods. Protein samples were subjected to nanoscale tandem mass spectrometry. Acquired peptides sequences were examined against the Cannabis sativa database to establish protein identity. Non-specific lipid transfer protein (Can s 3) level was measured using a recently developed ELISA 2.0 assay. Proteomic analysis identified 49 distinct potential allergens in protein extracts from all chemotypes. Most importantly, clinically relevant and validated allergens, such as profilin (Can s 2), Can s 3 and Bet v 1-domain-containing protein 10 (Can s 5), were identified in all chemotypes at label-free quantification (LFP) intensities > 106. However, the oxygen evolving enhancer protein 2 (Can s 4) was not detected in any of the protein samples. Similarly, Can s 2, Can s 3 and Can s 5 peptides were also detected in hemp protein extracts. The validation of these findings using the ELISA 2.0 assay indicated that hemp extract contains 30-37 ng of Can s 3 allergen per µg of total protein. Our proteomic studies indicate that relevant cannabis allergens are consistently expressed across distinct cannabis chemotypes. Further, hemp may serve as an ideal practical substitute for clinical testing, since it expresses most allergens relevant to cannabis sensitization, including the validated major allergen Can s 3.

Identification of a β-arrestin-biased negative allosteric modulator for the β2-adrenergic receptor

Catecholamine-stimulated β2-adrenergic receptor (β2AR) signaling via the canonical Gs-adenylyl cyclase-cAMP-PKA pathway regulates numerous physiological functions, including the therapeutic effects of exogenous β-agonists in the treatment of airway disease. β2AR signaling is tightly regulated by GRKs and β-arrestins, which together promote β2AR desensitization and internalization as well as downstream signaling, often antithetical to the canonical pathway. Thus, the ability to bias β2AR signaling toward the Gs pathway while avoiding β-arrestin-mediated effects may provide a strategy to improve the functional consequences of β2AR activation. Since attempts to develop Gs-biased agonists and allosteric modulators for the β2AR have been largely unsuccessful, here we screened small molecule libraries for allosteric modulators that selectively inhibit β-arrestin recruitment to the receptor. This screen identified several compounds that met this profile, and, of these, a difluorophenyl quinazoline (DFPQ) derivative was found to be a selective negative allosteric modulator of β-arrestin recruitment to the β2AR while having no effect on β2AR coupling to Gs. DFPQ effectively inhibits agonist-promoted phosphorylation and internalization of the β2AR and protects against the functional desensitization of β-agonist mediated regulation in cell and tissue models. The effects of DFPQ were also specific to the β2AR with minimal effects on the β1AR. Modeling, mutagenesis, and medicinal chemistry studies support DFPQ derivatives binding to an intracellular membrane-facing region of the β2AR, including residues within transmembrane domains 3 and 4 and intracellular loop 2. DFPQ thus represents a class of biased allosteric modulators that targets an allosteric site of the β2AR.

Early Feeding and Weaning Practices of Indian Children with Early Childhood Caries: A Qualitative Exploration

OBJECTIVE

To describe the early feeding, weaning, and oral hygiene practices of children with early childhood caries (ECC), their parents' knowledge and attitudes regarding infant feeding, and the feeding-related challenges faced by the parents.

METHODS

This descriptive qualitative study involved parents of children with ECC who sought dental treatment at an academic dental college in India. Data were collected though focus groups conducted with the 27 parents of children with ECC, using a focus group discussion guide. Data were analyzed using the content analysis method.

RESULTS

Community norms, such as learning from the older women in the families or neighborhoods, guided the feeding method, duration of feeding, and weaning. Breastfeeding or bottle-feeding at bedtime beyond 12 mo of age and feeding sugary drinks during weaning were standard practices, despite knowing the risk for dental caries. Parents faced multiple challenges regarding weaning and were unaware of the significance of infant oral hygiene practices.

CONCLUSION

In children with ECC, infant feeding practices included prolonged breastfeeding or bottle-feeding beyond the required age, feeding at bedtime, and feeding sugary drinks. Although the parents knew that these feeding habits could increase the risk for caries, they lacked the self-efficacy to translate their knowledge into action during weaning. Also, they lacked awareness regarding infant oral hygiene practices.

KNOWLEDGE TRANSFER STATEMENT

The study provides information on the feeding habits of infants that can increase the risk for caries, the challenges faced by the parents of these children in altering these risky habits, and their lack of knowledge on infant oral hygiene practices. Policy/decision makers can advocate for pediatricians and pediatric dentists to incorporate anticipatory guidance or motivational interviewing techniques to tailor the preventive program for ECC for Indian children.

A review of cannabis allergy in the early days of legalization

Cannabis allergy is a burgeoning field; consequently, research is still in its infancy and allergists' knowledge surrounding this topic is limited. As cannabis legalization expands across the world, it is anticipated that there will be an increase in cannabis use. Thus, we hypothesize that a concomitant rise in the incidence of allergy to this plant can be expected. Initiatives aimed at properly educating health care professionals are therefore necessary. This review presents the most up-to-date information on a broad range of topics related to cannabis allergy. Although the clinical features of cannabis allergy are becoming more well described and recognized, the tools available to make a correct diagnosis are meager and often poorly accessible. In addition, research on cannabis allergy is still taking its first steps, and new and potentially groundbreaking findings in this field are expected to occur in the next few years. Finally, although therapeutic approaches are being developed, patient and physician education regarding cannabis allergy is certainly needed.

Immunomodulatory Actions of Cannabinoids: Clinical Correlates and Therapeutic Opportunities for Allergic Inflammation

Endogenously produced cannabinoids as well as phytocannabinoids broadly exhibit anti-inflammatory actions. Recent emergence of cannabis for multiple medical issues combined with reports on potent immunomodulatory actions of distinct components has underscored the therapeutic potential of cannabis. Although synthetic cannabinoids that are based on structural similarities to the existing class of cannabinoids have been on the rise, their application in therapeutics have been limited owing to toxicity concerns. Herein, we review the current literature that details the immunomodulatory actions of cannabinoids. Further, we highlight the complexities of cannabinoid biology and examine the potential inflammatory risks associated with the use of cannabis including potential for toxic interactions between distinct constituents of cannabis.

Targeted Inhibition of Select Extracellular Signal-regulated Kinases 1 and 2 Functions Mitigates Pathological Features of Asthma in Mice

ERK1/2 (extracellular signal-regulated kinases 1 and 2) regulate the activity of various transcription factors that contribute to asthma pathogenesis. Although an attractive drug target, broadly inhibiting ERK1/2 is challenging because of unwanted cellular toxicities. We have identified small molecule inhibitors with a benzenesulfonate scaffold that selectively inhibit ERK1/2-mediated activation of AP-1 (activator protein-1). Herein, we describe the findings of targeting ERK1/2-mediated substrate-specific signaling with the small molecule inhibitor SF-3-030 in a murine model of house dust mite (HDM)-induced asthma. In 8- to 10-week-old BALB/c mice, allergic asthma was established by repeated intranasal HDM (25 μg/mouse) instillation for 3 weeks (5 days/week). A subgroup of mice was prophylactically dosed with 10 mg/kg SF-3-030/DMSO intranasally 30 minutes before the HDM challenge. Following the dosing schedule, mice were evaluated for alterations in airway mechanics, inflammation, and markers of airway remodeling. SF-3-030 treatment significantly attenuated HDM-induced elevation of distinct inflammatory cell types and cytokine concentrations in BAL and IgE concentrations in the lungs. Histopathological analysis of lung tissue sections revealed diminished HDM-induced pleocellular peribronchial inflammation, mucus cell metaplasia, collagen accumulation, thickening of airway smooth muscle mass, and expression of markers of cell proliferation (Ki-67 and cyclin D1) in mice treated with SF-3-030. Furthermore, SF-3-030 treatment attenuated HDM-induced airway hyperresponsiveness in mice. Finally, mechanistic studies using transcriptome and proteome analyses suggest inhibition of HDM-induced genes involved in inflammation, cell proliferation, and tissue remodeling by SF-3-030. These preclinical findings demonstrate that function-selective inhibition of ERK1/2 signaling mitigates multiple features of asthma in a murine model.

A novel application of a bioactive material as a pit and fissure sealant: in vitro pilot study evaluating the sealing ability and penetration

PURPOSE

To compare the sealing ability and penetration of a bioactive material used as pit and fissure sealant to those of glass ionomer sealant.

METHODS

This was an in vitro experimental study conducted on 20 permanent teeth. For Group I of ten teeth, ACTIVA BioACTIVE-Base/Liner was applied as a sealant on pits and fissures, and the remaining ten teeth of Group II were sealed using glass ionomer cement. After thermocycling, the apex of the teeth was sealed using composite resin and they were immersed in 1% methylene blue solution, buffered at pH 7 for 24 h. Longitudinal sections were obtained from each tooth for evaluating the sealing ability and penetration, using a binocular light microscope at 4 × magnification. The obtained data were subjected to analysis using the Chi-square test and independent t test.

RESULTS

The comparison of the sealing ability and sealant penetration, between the two groups, showed statistically no significant difference (p = 0.104 and p = 1.0, respectively).

CONCLUSION

Bioactive material as a pit and fissure sealant, performed on par with glass ionomer sealant in terms of tested properties like sealing ability and penetration.

Impact of cannabis knowledge and attitudes on real-world practice

BACKGROUND

Increased cannabis consumption worldwide challenges allergists because of an upsurge in cannabis allergy and need to discuss cannabis with patients.

OBJECTIVE

To determine the knowledge, attitudes, and practices regarding cannabis among allergists and their approach to recognizing and diagnosing suspected cannabis allergy.

METHODS

The International Allergist Canna Knowledge, Attitudes, and Practices Survey was completed by members from 3 International Allergy Societies. Survey questions included the following: 13 on cannabis attitudes, 7 on cannabis knowledge, and 4 on real-world allergy practices. Knowledge level was dichotomized and Statistical Package for the Social Sciences TwoStep Cluster Analysis grouped participants by attitudes. Multivariate analysis determined the relationship of knowledge and attitude to practice delivery.

RESULTS

Of 570 eligible surveys started, 445 (78.1%) were completed. Participants were 49.7% of female sex, 65.9% aged 24 to 56 years, approximately 70% in practice for more than or equal to 10 years, and 29.2% practicing in an area where cannabis use is illegal. Of the respondents, 43.1% reported consulting on patients with suspected cannabis allergy and 54.7% had undertaken skin prick testing, in vitro cannabis testing, or both. Statistically significant differences were found between the 3 societies for most variables analyzed. Analysis of attitudes revealed 3 clusters named Traditional, Progressive, and Unsure. Those with more progressive attitudes toward cannabis and who had more knowledge were more comfortable speaking to patients about cannabis and more often asked patients on how often and how they used cannabis (all P < .001).

CONCLUSION

Varying knowledge and attitudes toward cannabis affecting comfort communicating with patients about cannabis were found in members of 3 allergy societies supporting the need for more cannabis research and education.

Cannabis-related allergies: An international overview and consensus recommendations

Cannabis is the most widely used recreational drug in the world. Cannabis sativa and Cannabis indica have been selectively bred to develop their psychoactive properties. The increasing use in many countries has been accelerated by the COVID-19 pandemic. Cannabis can provoke both type 1 and type 4 allergic reactions. Officially recognized allergens include a pathogenesis-related class 10 allergen, profilin, and a nonspecific lipid transfer protein. Other allergens may also be relevant, and recognition of allergens may vary between countries and continents. Cannabis also has the potential to provoke allergic cross-reactions to plant foods. Since cannabis is an illegal substance in many countries, research has been hampered, leading to challenges in diagnosis since no commercial extracts are available for testing. Even in countries such as Canada, where cannabis is legalized, diagnosis may rely solely on the purchase of cannabis for prick-to-prick skin tests. Management consists of avoidance, with legal issues hindering the development of other treatments such as immunotherapy. Education of healthcare professionals is similarly lacking. This review aimed to summarize the current status of cannabis allergy and proposes recommendations for the future management of this global issue.

OGR1-dependent regulation of the allergen-induced asthma phenotype

The proton-sensing receptor, ovarian cancer G protein-coupled receptor (OGR1), has been shown to be expressed in airway smooth muscle (ASM) cells and is capable of promoting ASM contraction in response to decreased extracellular pH. OGR1 knockout (OGR1KO) mice are reported to be resistant to the asthma features induced by inhaled allergen. We recently described certain benzodiazepines as OGR1 activators capable of mediating both procontractile and prorelaxant signaling in ASM cells. Here we assess the effect of treatment with the benzodiazepines lorazepam or sulazepam on the asthma phenotype in wild-type (WT) and OGR1KO mice subjected to inhaled house dust mite (HDM; Dermatophagoides pteronyssius) challenge for 3 wk. In contrast to previously published reports, both WT and OGR1KO mice developed significant allergen-induced lung inflammation and airway hyperresponsiveness (AHR). In WT mice, treatment with sulazepam (a Gs-biased OGR1 agonist), but not lorazepam (a balanced OGR1 agonist), prevented allergen-induced AHR, although neither drug inhibited lung inflammation. The protection from development of AHR conferred by sulazepam was absent in OGR1KO mice. Treatment of WT mice with sulazepam also resulted in significant inhibition of HDM-induced collagen accumulation in the lung tissue. These findings suggest that OGR1 expression is not a requirement for development of the allergen-induced asthma phenotype, but OGR1 can be targeted by the Gs-biased OGR1 agonist sulazepam (but not the balanced agonist lorazepam) to protect from allergen-induced AHR, possibly mediated via suppression of chronic bronchoconstriction and airway remodeling in the absence of effects on airway inflammation.

Diacylglycerol Kinase Inhibition Reduces Airway Contraction by Negative Feedback Regulation of Gq-signaling

Exaggerated airway smooth muscle (ASM) contraction regulated by the Gq family of G protein-coupled receptors (GPCRs) causes airway hyperresponsiveness (AHR) in asthma. Activation of Gq-coupled GPCRs leads to phospholipase C (PLC)-mediated generation of inositol triphosphate (IP3) and diacylglycerol (DAG). DAG signaling is terminated by the action of DAG kinase (DGK) that converts DAG into phosphatidic acid (PA). Our previous study demonstrated that DGKα and ζ isoform knockout mice are protected from the development of allergen-induced AHR. Here we aimed at determining the mechanism by which DGK regulates ASM contraction. Activity of DGK isoforms was inhibited in human ASM cells by siRNA-mediated knockdown of DGKα and ζwhile pharmacological inhibition was achieved by pan DGK inhibitor I (R59022). Effects of DGK inhibition on contractile agonist-induced activation of PLC and myosin light chain (MLC) kinase, elevation of IP3, and calcium levels were assessed. Further, we employed human precision-cut lung slices and assessed the role of DGK in agonist-induced bronchoconstriction. DGK inhibitor I attenuated histamine- and methacholine-induced bronchoconstriction. DGKα and ζ knockdown or pre-treatment with DGK inhibitor I resulted in attenuated agonist-induced phosphorylation of MLC and myosin light chain phosphatase in ASM cells. Further, DGK inhibition decreased Gq agonist-induced calcium elevation, generation of IP3, and increased histamine-induced production of PA. Finally, DGK inhibition or treatment with DAG analog resulted in attenuation of activation of PLC in human ASM cells. Our findings suggest that DGK inhibition perturbed the DAG:PA ratio resulting in inhibition of Gq-PLC activation in a negative feedback manner, resulting in protection against ASM contraction.

Cooperativity between β-agonists and c-Abl inhibitors in regulating airway smooth muscle relaxation

Current therapeutic approaches to avoid or reverse bronchoconstriction rely primarily on β2 adrenoceptor agonists (β-agonists) that regulate pharmacomechanical coupling/cross bridge cycling in airway smooth muscle (ASM). Targeting actin cytoskeleton polymerization in ASM represents an alternative means to regulate ASM contraction. Herein we report the cooperative effects of targeting these distinct pathways with β-agonists and inhibitors of the mammalian Abelson tyrosine kinase (Abl1 or c-Abl). The cooperative effect of β-agonists (isoproterenol) and c-Abl inhibitors (GNF-5, or imatinib) on contractile agonist (methacholine, or histamine) -induced ASM contraction was assessed in cultured human ASM cells (using Fourier Transfer Traction Microscopy), in murine precision cut lung slices, and in vivo (flexiVent in mice). Regulation of intracellular signaling that regulates contraction (pMLC20, pMYPT1, pHSP20), and actin polymerization state (F:G actin ratio) were assessed in cultured primary human ASM cells. In each (cell, tissue, in vivo) model, c-Abl inhibitors and β-agonist exhibited additive effects in either preventing or reversing ASM contraction. Treatment of contracted ASM cells with c-Abl inhibitors and β-agonist cooperatively increased actin disassembly as evidenced by a significant reduction in the F:G actin ratio. Mechanistic studies indicated that the inhibition of pharmacomechanical coupling by β-agonists is near optimal and is not increased by c-Abl inhibitors, and the cooperative effect on ASM relaxation resides in further relaxation of ASM tension development caused by actin cytoskeleton depolymerization, which is regulated by both β-agonists and c-Abl inhibitors. Thus, targeting actin cytoskeleton polymerization represents an untapped therapeutic reserve for managing airway resistance.

Occupational Allergies to Cannabis

Within the last decade there has been a significant expansion in access to cannabis for medicinal and adult nonmedical use in the United States and abroad. This has resulted in a rapidly growing and diverse workforce that is involved with the growth, cultivation, handling, and dispensing of the cannabis plant and its products. The objective of this review was to educate physicians on the complexities associated with the health effects of cannabis exposure, the nature of these exposures, and the future practical challenges of managing these in the context of allergic disease. We will detail the biological hazards related to typical modern cannabis industry operations that may potentially drive allergic sensitization in workers. We will highlight the limitations that have hindered the development of objective diagnostic measures that are essential in separating "true" cannabis allergies from nonspecific reactions/irritations that "mimic" allergy-like symptoms. Finally, we will discuss recent advances in the basic and translational scientific research that will aid the development of diagnostic tools and therapeutic standards to serve optimal management of cannabis allergies across the occupational spectrum.

Cannabis: An Emerging Occupational Allergen?

Cannabis is the most commonly used psychoactive drug. In recent years, Cannabis access has expanded for both medicinal and non-medicinal has grown. This is also marked with an increasing number of individuals gaining employment in this emerging industry. In this article, we briefly discuss the health hazards associated with Cannabis exposure with an emphasis on the potential for allergic reactions in workers who handle and process Cannabis plant.

Inhalation of Stachybotrys chartarum Fragments Induces Pulmonary Arterial Remodeling

Stachybotrys chartarum is a fungal contaminant within the built environment and a respiratory health concern in the United States. The objective of this study was to characterize the mechanisms influencing pulmonary immune responses to repeatedly inhaled S. chartarum. Groups of B6C3F1/N mice repeatedly inhaled viable trichothecene-producing S. chartarum conidia (strain A or strain B), heat-inactivated conidia, or high-efficiency particulate absolute-filtered air twice per week for 4 and 13 weeks. Strain A was found to produce higher amounts of respirable fragments than strain B. Lung tissue, serum, and BAL fluid were collected at 24 and 48 hours after final exposure and processed for histology, flow cytometry, and RNA and proteomic analyses. At 4 weeks after exposure, a T-helper cell type 2-mediated response was observed. After 13 weeks, a mixed T-cell response was observed after exposure to strain A compared with a T-helper cell type 2-mediated response after strain B exposure. After exposure, both strains induced pulmonary arterial remodeling at 13 weeks; however, strain A-exposed mice progressed more quickly than strain B-exposed mice. BAL fluid was composed primarily of eosinophils, neutrophils, and macrophages. Both the immune response and the observed pulmonary arterial remodeling were supported by specific cellular, molecular, and proteomic profiles. The immunopathological responses occurred earlier in mice exposed to high fragment-producing strain A. The rather striking induction of pulmonary remodeling by S. chartarum appears to be related to the presence of fungal fragments during exposure.

Discovery of Human Signaling Systems: Pairing Peptides to G Protein-Coupled Receptors

The peptidergic system is the most abundant network of ligand-receptor-mediated signaling in humans. However, the physiological roles remain elusive for numerous peptides and more than 100 G protein-coupled receptors (GPCRs). Here we report the pairing of cognate peptides and receptors. Integrating comparative genomics across 313 species and bioinformatics on all protein sequences and structures of human class A GPCRs, we identify universal characteristics that uncover additional potential peptidergic signaling systems. Using three orthogonal biochemical assays, we pair 17 proposed endogenous ligands with five orphan GPCRs that are associated with diseases, including genetic, neoplastic, nervous and reproductive system disorders. We also identify additional peptides for nine receptors with recognized ligands and pathophysiological roles. This integrated computational and multifaceted experimental approach expands the peptide-GPCR network and opens the way for studies to elucidate the roles of these signaling systems in human physiology and disease.

Video Abstract

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Universal characteristics enabled prediction of peptide ligands and receptors

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Multifaceted screening enabled detection of pathway- and assay-dependent responses

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Peptide ligands discovered for BB₃, GPR1, GPR15, GPR55, and GPR68

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Each signaling system is a link to human physiology and is associated with disease

The proton-sensing receptor ovarian cancer G-protein coupled receptor 1 (OGR1) in airway physiology and disease

Numerous G protein-coupled receptors (GPCRs) regulate multiple airway functions and play fundamental roles in normal and aberrant airway and lung physiology. Thus, GPCRs are prime candidates of targeting by disease therapeutics. The intriguing proton-sensing GPCR Ovarian cancer G-protein coupled receptor 1 (OGR1; aka GPR68) has recently been shown capable of regulating airway smooth muscle (ASM) contraction and proliferation. Although the study of OGR1 has been confounded by the fact that the proton is the presumed cognate ligand of OGR1, recent studies have begun to identify novel ligands and modulators capable of regulating the diverse signaling, and functional role of OGR1. Such studies offer hope for OGR1-targeting drugs as therapeutics for obstructive lung diseases such as asthma. Herein, we review the literature to date detailing the receptor biology and pharmacology of OGR1, receptor function in the airway, and describe the potential clinical utility of OGR1-modulating drugs.

Therapeutic potential and challenges of bitter taste receptors on lung cells

Airway smooth muscle (ASM) hyperresponsiveness and airway remodeling are pathological drivers of disease progression and mortality in asthma. Importantly, approximately 50% of affected individuals are unable to reliably manage disease symptoms using the current standard of care. Recently, T2Rs have been identified as a novel class of G protein-coupled receptors expressed in the airway that on activation can induce ASM relaxation and reduction in airway tone. Further, agonists of T2Rs may also remedy airway remodeling, which has been difficult to manage with currently available medications. In this review, we will discuss the recent developments in T2R biology and their role in cellular physiology (particularly ASM) and expand on the therapeutic potential of T2R agonists in treatment of asthma.

Bitter Taste Receptors: an Answer to Comprehensive Asthma Control?

PURPOSE OF REVIEW

Asthma is marked by peculiar pathological features involving airway contraction, an impinging inflammation in the lungs, and an inexorably progressive remodeling of pulmonary architecture. Current medications for management of asthma exacerbations fail to optimally mitigate these pathologies, which is partly due to the intrinsic heterogeneity in the development and progression of asthma within different populations. In recent years, the discovery of the ectopic expression of TAS2Rs in extraoral tissues and different cell types, combined with significant strides in gaining mechanistic understanding into receptor signaling and function, has revealed the potential to target TAS2Rs for asthma relief.

RECENT FINDINGS

TAS2R activation leads to relaxation of airway smooth muscle cells and bronchodilation. In addition, findings from preclinical studies in murine model of asthma suggest that TAS2R agonists inhibit allergen-induced airway inflammation, remodeling, and hyperresponsiveness. In this review, we expand on the opportunity presented by TAS2Rs in the development of a comprehensive asthma treatment that overcomes the limitations set forth by current asthma therapeutics.

Bitter Taste Receptors for Asthma Therapeutics

Clinical management of asthma and chronic obstructive pulmonary disease (COPD) has primarily relied on the use of beta 2 adrenergic receptor agonists (bronchodilators) and corticosteroids, and more recently, monoclonal antibody therapies (biologics) targeting specific cytokines and their functions. Although these approaches provide relief from exacerbations, questions remain on their long-term efficacy and safety. Furthermore, current therapeutics do not address progressive airway remodeling (AR), a key pathological feature of severe obstructive lung disease. Strikingly, agonists of the bitter taste receptors (TAS2Rs) deliver robust bronchodilation, curtail allergen-induced inflammatory responses in the airways and regulate airway smooth muscle (ASM) cell proliferation and mitigate features of AR in vitro and in animal models. The scope of this review is to provide a comprehensive and systematic insight into our current understanding of TAS2Rs with an emphasis on the molecular events that ensue TAS2R activation in distinct airway cell types and expand on the pleiotropic effects of TAS2R targeting in mitigating various pathological features of obstructive lung diseases. Finally, we will discuss specific opportunities that could help the development of selective agonists for specific TAS2R subtypes in the treatment of asthma.

Regulation of ovarian cancer G protein-coupled receptor-1 expression and signaling

Ovarian cancer G protein-coupled receptor 1 (OGR1) is a recently deorphanized G protein-coupled receptor shown to signal in response to low extracellular pH (↓pH_o) or certain benzodiazepines. The pleiotropic nature of OGR1 signaling in human airway smooth muscle (HASM) cells suggests that OGR1 is a potential therapeutic target for the management of obstructive lung diseases. However, the basic pharmacological and regulatory features of OGR1 remain poorly understood. We employed model systems of heterologously expressed [human embryonic kidney 293 (HEK293) cells] or endogenous (HASM) OGR1 to assess changes in expression, subcellular localization, and signaling capabilities following acute or chronic treatment with ↓pH_o or the benzodiazepines lorazepam and sulazepam. In HEK293 cells expressing OGR1, treatment with ↓pH_o and/or lorazepam, but not sulazepam, caused rapid OGR1 internalization. In HASM cells, acute treatment with ↓pH_o or benzodiazepines did not alter abundance of OGR1 mRNA; however, significant downregulation was observed following chronic treatment. Acute and chronic pretreatment of HASM cells with sulazepam or lorazepam resulted in receptor desensitization as demonstrated by reduced phosphorylation of vasodilator-stimulated phosphoprotein (VASP) or p42/p44 upon rechallenge. Acid (acute but not chronic) pretreatment of HASM cells induced desensitization of OGR1-mediated VASP (but not p42/p44) phosphorylation. In contrast to a recent study reporting OGR1 upregulation and sensitization in cardiac tissue subject to ischemic/acidic insult, chronic OGR1 activation in multiple model systems did not increase OGR1 expression or signaling capacity. The ability to induce OGR1 internalization and desensitization was activator dependent, reflecting the ability of different activators to induce specific receptor confirmations and engagement of specific heterotrimeric G proteins.

Cooperativity of E-prostanoid receptor subtypes in regulating signaling and growth inhibition in human airway smooth muscle

Prostaglandin E2 (PGE₂) is produced in the airway during allergic lung inflammation and both promotes and inhibits features of asthma pathology. These mixed effects relate to 4 E-prostanoid (EP) receptor subtypes (EP1, 2, 3 and 4) expressed at different levels on different resident and infiltrating airway cells. Although studies have asserted both EP2 and EP4 expression in human airway smooth muscle (HASM), a recent study asserted EP4 to be the functionally dominant EP subtype in HASM. Herein, we employ recently-developed subtype-selective ligands to investigate singular or combined EP2 and EP4 receptor activation in regulating HASM signaling and proliferation. The subtype specificity of ONO-AE1-259-01 (EP2 agonist) and ONO-AE1-329 (EP4 agonist) was first demonstrated in human embryonic kidney 293 cells stably expressing different EP receptor subtypes. EP receptor knockdown and subtype-selective antagonists demonstrated EP2 and EP4 receptor responsiveness in HASM cells to the specific ONO compounds, whereas PGE₂ appeared to preferentially signal via the EP4 receptor. Both singular EP2 and EP4 receptor agonists inhibited HASM proliferation, and combined EP2 and EP4 receptor agonism exhibited positive cooperativity in both chronic G_s-mediated signaling and inhibiting HASM proliferation. These findings suggest both EP2 and EP4 are functionally important in HASM, and their combined targeting optimally inhibits airway smooth muscle proliferation.-Michael, J. V. Gavrila, A., Nayak, A. P., Pera, T., Liberato, J. R., Polischak, S. R., Shah, S. D., Deshpande, D. A., Penn, R. B. Cooperativity of E-prostanoid receptor subtypes in regulating signaling and growth inhibition in human airway smooth muscle.

New targets for resolution of airway remodeling in obstructive lung diseases

Airway remodeling (AR) is a progressive pathological feature of the obstructive lung diseases, including asthma and chronic obstructive pulmonary disease (COPD). The pathology manifests itself in the form of significant, progressive, and (to date) seemingly irreversible changes to distinct respiratory structural compartments. Consequently, AR correlates with disease severity and the gradual decline in pulmonary function associated with asthma and COPD. Although current asthma/COPD drugs manage airway contraction and inflammation, none of these effectively prevent or reverse features of AR. In this review, we provide a brief overview of the features and putative mechanisms affecting AR. We further discuss recently proposed strategies with promise for deterring or treating AR.

Microbial hazards during harvesting and processing at an outdoor United States cannabis farm

Cannabis cultivation is an emerging industry within the United States. Organic dust derived in part from naturally occurring microorganisms is known to cause byssinosis in the hemp industry. In this pilot study, bacteria and fungi encountered by workers at an outdoor cannabis farm that utilized organic practices were elucidated by 16 S ribosomal RNA (rRNA) and Internal Transcribed Spacer (ITS) region sequencing, respectively. Area (n = 14) and personal air samples (n = 12) were collected during harvesting and processing activities. 16 S rRNA and ITS regions of extracted bacterial and fungal genomic DNA were amplified and sequenced using Sanger sequencing. Bacterial sequencing resolved 1,077 sequences that were clustered into 639 operational taxonomic units (OTUs) and predominantly placed in the phylum, Actinobacteria (46%). Personal air samples revealed higher bacterial and Actinobacteria diversity compared to outdoor area samples collected within the facility (p < 0.05). A high degree of dissimilarity between bacteria was identified within and between samples. Fungal sequences (n = 985) were identified and predominantly clustered in the phylum Ascomycota (53%). Of the 216 fungal OTUs elucidated, the cannabis plant pathogenic species, Botrytis cinerea, was the most prevalent and accounted for 34% of all fungal sequences. The relative abundance of B. cinerea was highest in personal air samples (59%) compared to area samples collected in the drying room (19%), greenhouse (18%), and outdoor environment (6%). There was 49% sample similarity between fungi identified within personal air samples, but higher dissimilarity coefficients were observed within and between greenhouse, drying room, and outdoor area air samples. The results of this pilot study suggest that the cannabis farm workers are potentially exposed to Actinobacteria as well as the cannabis plant pathogen, B. cinerea during harvesting, bud-stripping, and hand-trimming processes.

Aspergillus fumigatus viability drives allergic responses to inhaled conidia

BACKGROUND

Aspergillus fumigatus-induced allergic airway disease has been shown to involve conidial germination in vivo, but the immunological mechanisms remain uncharacterized.

OBJECTIVE

A subchronic murine exposure model was used to examine the immunological mediators that are regulated in response to either culturable or nonculturable A fumigatus conidia.

METHODS

Female B6C3F1/N mice were repeatedly dosed via inhalation with 1 × 105 viable or heat-inactivated conidia (HIC), twice per week for 13 weeks (26 exposures). Control mice inhaled high-efficiency particulate arrestor-filtered air. The influence of A fumigatus conidial germination on the pulmonary immunopathological outcomes was evaluated by flow cytometry analysis of cellular infiltration in the airways, assessment of lung messenger RNA expression, quantitative proteomics, and histopathology of whole lung tissue.

RESULTS

Repeated inhalation of viable conidia, but not HIC, resulted in allergic inflammation marked by vascular remodeling, extensive eosinophilia, and accumulation of alternatively activated macrophages (AAMs) in the murine airways. More specifically, mice that inhaled viable conidia resulted in a mixed TH1 and TH2 (IL-13) cytokine response. Recruitment of eosinophils corresponded with increased Ccl11 transcripts. Furthermore, genes associated with M2 or alternatively activated macrophage polarization (eg, Arg1, Chil3, and Retnla) were significantly up-regulated in viable A fumigatus-exposed mice. In mice inhaling HIC, CD4+ T cells expressing IFN-γ (TH1) dominated the lymphocytic infiltration. Quantitative proteomics of the lung revealed metabolic reprogramming accompanied by mitochondrial dysfunction and endoplasmic reticulum stress stimulated by oxidative stress from repetitive microbial insult.

CONCLUSION

Our studies demonstrate that A fumigatus conidial viability in vivo is critical to the immunopathological presentation of chronic fungal allergic disease.

Biased signaling of the proton-sensing receptor OGR1 by benzodiazepines

GPCRs have diverse signaling capabilities, based on their ability to assume various conformations. Moreover, it is now appreciated that certain ligands can promote distinct receptor conformations and thereby bias signaling toward a specific pathway to differentially affect cell function. The recently deorphanized G protein-coupled receptor OGR1 [ovarian cancer G protein-coupled receptor 1 ( GPR68)] exhibits diverse signaling events when stimulated by reductions in extracellular pH. We recently demonstrated airway smooth muscle cells transduce multiple signaling events, reflecting a diverse capacity to couple to multiple G proteins. Moreover, we recently discovered that the benzodiazepine lorazepam, more commonly recognized as an agonist of the γ-aminobutyric acid A (GABAA) receptor, can function as an allosteric modulator of OGR1 and, similarly, can promote multiple signaling events. In this study, we demonstrated that different benzodiazepines exhibit a range of biases for OGR1, with sulazepam selectively activating the canonical Gs of the G protein signaling pathway, in heterologous expression systems, as well as in several primary cell types. These findings highlight the potential power of biased ligand pharmacology for manipulating receptor signaling qualitatively, to preferentially activate pathways that are therapeutically beneficial.-Pera, T., Deshpande, D. A., Ippolito, M., Wang, B., Gavrila, A., Michael, J. V., Nayak, A. P., Tompkins, E., Farrell, E., Kroeze, W. K., Roth, B. L., Panettieri, R. A. Jr Benovic, J. L., An, S. S., Dulin, N. O., Penn, R. B. Biased signaling of the proton-sensing receptor OGR1 by benzodiazepines.

Topical application of the anti-microbial chemical triclosan induces immunomodulatory responses through the S100A8/A9-TLR4 pathway

The anti-microbial compound triclosan is incorporated into numerous consumer products and is detectable in the urine of 75% of the general United States population. Recent epidemiological studies report positive associations with urinary triclosan levels and allergic disease. Although not sensitizing, earlier studies previously found that repeated topical application of triclosan augments the allergic response to ovalbumin (OVA) though a thymic stromal lymphopoietin (TSLP) pathway in mice. In the present study, early immunological effects following triclosan exposure were further evaluated following topical application in a murine model. These investigations revealed abundant expression of S100A8/A9, which reportedly acts as an endogenous ligand for Toll-like Receptor 4 (TLR4), in skin tissues and in infiltrating leukocytes during topical application of 0.75-3.0% triclosan. Expression of Tlr4 along with Tlr1, Tlr2 and Tlr6 increased in skin tissues over time with triclosan exposure; high levels of TLR4 were expressed on skin-infiltrating leukocytes. In vivo antibody blockade of the TLR4/MD-2 receptor complex impaired local inflammatory responses after four days, as evidenced by decreased Il6, Tnfα, S100a8, S100a9, Tlr1, Tlr2, Tlr4 and Tlr6 expression in the skin and decreased lymph node cellularity and production of IL-4 and IL-13 by lymph node T-cells. After nine days of triclosan exposure with TLR4/MD-2 blockade, impaired T-helper cell type 2 (T_H2) cytokine responses were sustained, but other early effects on skin and lymph node cellularity were lost; this suggested alternative ligands/receptors compensated for the loss of TLR4 signaling. Taken together, these data suggest the S100A8/A9-TLR4 pathway plays an early role in augmenting immunomodulatory responses with triclosan exposure and support a role for the innate immune system in chemical adjuvancy.

Influence of Aspergillus fumigatus conidia viability on murine pulmonary microRNA and mRNA expression following subchronic inhalation exposure

BACKGROUND

Personal exposure to fungal bioaerosols derived from contaminated building materials or agricultural commodities may induce or exacerbate a variety of adverse health effects. The genomic mechanisms that underlie pulmonary immune responses to fungal bioaerosols have remained unclear.

OBJECTIVE

The impact of fungal viability on the pulmonary microRNA and messenger RNA profiles that regulate murine immune responses was evaluated following subchronic inhalation exposure to Aspergillus fumigatus conidia.

METHODS

Three groups of naïve B6C3F1/N mice were exposed via nose-only inhalation to A. fumigatus viable conidia, heat-inactivated conidia (HIC), or HEPA-filtered air twice a week for 13 weeks. Total RNA was isolated from whole lung 24 and 48 h postfinal exposure and was further processed for gene expression and microRNA array analysis. The molecular network pathways between viable and HIC groups were evaluated.

RESULTS

Comparison of data sets revealed increased Il4, Il13 and Il33 expression in mice exposed to viable vs. HIC. Of 415 microRNAs detected, approximately 50% were altered in mice exposed to viable vs. HIC 48 h postexposure. Significantly down-regulated (P ≤ 0.05) miR-29a-3p was predicted to regulate TGF-β3 and Clec7a, genes involved in innate responses to viable A. fumigatus. Also significantly down-regulated (P ≤ 0.05), miR-23b-3p regulates genes involved in pulmonary IL-13 and IL-33 responses and SMAD2, downstream of TGF-β signalling. Using Ingenuity Pathway Analysis, a novel interaction was identified between viable conidia and SMAD2/3.

CONCLUSIONS AND CLINICAL RELEVANCE

Examination of the pulmonary genetic profiles revealed differentially expressed genes and microRNAs following subchronic inhalation exposure to A. fumigatus. MicroRNAs regulating genes involved in the pulmonary immune responses were those with the greatest fold change. Specifically, germinating A. fumigatus conidia were associated with Clec7a and were predicted to interact with Il13 and Il33. Furthermore, altered microRNAs may serve as potential biomarkers to evaluate fungal exposure.

Subchronic exposures to fungal bioaerosols promotes allergic pulmonary inflammation in naïve mice

BACKGROUND

Epidemiological surveys indicate that occupants of mold contaminated environments are at increased risk of respiratory symptoms. The immunological mechanisms associated with these responses require further characterization.

OBJECTIVE

The aim of this study was to characterize the immunotoxicological outcomes following repeated inhalation of dry Aspergillus fumigatus spores aerosolized at concentrations potentially encountered in contaminated indoor environments.

METHODS

Aspergillus fumigatus spores were delivered to the lungs of naïve BALB/cJ mice housed in a multi-animal nose-only chamber twice a week for a period of 13 weeks. Mice were evaluated at 24 and 48 h post-exposure for histopathological changes in lung architecture, recruitment of specific immune cells to the airways, and serum antibody responses.

RESULT

Germinating A. fumigatus spores were observed in lungs along with persistent fungal debris in the perivascular regions of the lungs. Repeated exposures promoted pleocellular infiltration with concomitant epithelial mucus hypersecretion, goblet cell metaplasia, subepithelial fibrosis and enhanced airway hyperreactivity. Cellular infiltration in airways was predominated by CD4(+) T cells expressing the pro-allergic cytokine IL-13. Furthermore, our studies show that antifungal T cell responses (IFN-γ(+) or IL-17A(+) ) co-expressed IL-13, revealing a novel mechanism for the dysregulated immune response to inhaled fungi. Total IgE production was augmented in animals repeatedly exposed to A. fumigatus.

CONCLUSIONS & CLINICAL RELEVANCE

Repeated inhalation of fungal aerosols resulted in significant pulmonary pathology mediated by dynamic shifts in specific immune populations and their cytokines. These studies provide novel insights into the immunological mechanisms and targets that govern the health outcomes that result from repeated inhalation of fungal bioaerosols in contaminated environments.

Production of a Chaetomium globosum enolase monoclonal antibody

Chaetomium globosum is a hydrophilic fungal species and a contaminant of water-damaged building materials in North America. Methods to detect Chaetomium species include subjective identification of ascospores, viable culture, or molecular-based detection methods. In this study, we describe the production and initial characterization of a monoclonal antibody (MAb) for C. globosum enolase. MAb 1C7, a murine IgG1 isotype MAb, was produced and reacted with recombinant C. globosum enolase (rCgEno) in an enzyme-linked immunosorbent assay and with a putative C. globosum enolase in a Western blot. Epitope mapping showed MAb 1C7 specific reactivity to an enolase decapeptide, LTYEELANLY, that is highly conserved within the fungal class Sordariomycetes. Cross-reactivity studies showed MAb 1C7 reactivity to C. atrobrunneum but not C. indicum. MAb 1C7 did not react with enolase from Aspergillus fumigatus, which is divergent in only two amino acids within this epitope. The results of this study suggest potential utility of MAb 1C7 in Western blot applications for the detection of Chaetomium and other Sordariomycetes species.

Characterization and comparative analysis of 2,4-toluene diisocyanate and 1,6-hexamethylene diisocyanate haptenated human serum albumin and hemoglobin

Diisocyanates (dNCOs) are low molecular weight chemical sensitizers that react with autologous proteins to produce neoantigens. dNCO-haptenated proteins have been used as immunogens for generation of dNCO-specific antibodies and as antigens to screen for dNCO-specific antibodies in exposed individuals. Detection of dNCO-specific antibodies in exposed individuals for diagnosis of dNCO asthma has been hampered by poor sensitivities of the assay methods in that specific IgE can only be detected in approximately 25% of the dNCO asthmatics. Apart from characterization of the conjugates used for these immunoassays, the choice of the carrier protein and the dNCO used are important parameters that can influence the detection of dNCO-specific antibodies. Human serum albumin (HSA) is the most common carrier protein used for detection of dNCO specific-IgE and -IgG but the immunogenicity and/or antigenicity of other proteins that may be modified by dNCO in vivo is not well documented. In the current study, 2,4-toluene diisocyanate (TDI) and 1,6-hexamethylene diisocyanate (HDI) were reacted with HSA and human hemoglobin (Hb) and the resultant adducts were characterized by (i) HPLC quantification of the diamine produced from acid hydrolysis of the adducts, (ii) 2,4,6-trinitrobenzene sulfonic acid (TNBS) assay to assess extent of cross-linking, (iii) electrophoretic migration in polyacrylamide gels to analyze intra- and inter-molecular cross-linking, and (iv) evaluation of antigenicity using a monoclonal antibody developed previously to TDI conjugated to Keyhole limpet hemocyanin (KLH). Concentration-dependent increases in the amount of dNCO bound to HDI and TDI, cross-linking, migration in gels, and antibody-binding were observed. TDI reactivity with both HSA and Hb was significantly higher than HDI. Hb-TDI antigenicity was approximately 30% that of HSA-TDI. In conclusion, this data suggests that both, the extent of haptenation as well as the degree of cross-linking differs between the two diisocyanate species studied, which may influence their relative immunogenicity and/or antigenicity.

Triclosan Induces Thymic Stromal Lymphopoietin in Skin Promoting Th2 Allergic Responses

Triclosan is an antimicrobial chemical incorporated into many personal, medical and household products. Approximately, 75% of the U.S. population has detectable levels of triclosan in their urine, and although it is not typically considered a contact sensitizer, recent studies have begun to link triclosan exposure with augmented allergic disease. We examined the effects of dermal triclosan exposure on the skin and lymph nodes of mice and in a human skin model to identify mechanisms for augmenting allergic responses. Triclosan (0%-3%) was applied topically at 24-h intervals to the ear pinnae of OVA-sensitized BALB/c mice. Skin and draining lymph nodes were evaluated for cellular responses and cytokine expression over time. The effects of triclosan (0%-0.75%) on cytokine expression in a human skin tissue model were also examined. Exposure to triclosan increased the expression of TSLP, IL-1β, and TNF-α in the skin with concomitant decreases in IL-25, IL-33, and IL-1α. Similar changes in TSLP, IL1B, and IL33 expression occurred in human skin. Topical application of triclosan also increased draining lymph node cellularity consisting of activated CD86(+)GL-7(+) B cells, CD80(+)CD86(+) dendritic cells, GATA-3(+)OX-40(+)IL-4(+)IL-13(+) Th2 cells and IL-17 A(+) CD4 T cells. In vivo antibody blockade of TSLP reduced skin irritation, IL-1β expression, lymph node cellularity, and Th2 responses augmented by triclosan. Repeated dermal exposure to triclosan induces TSLP expression in skin tissue as a potential mechanism for augmenting allergic responses.

Toluene diisocyanate (TDI) disposition and co-localization of immune cells in hair follicles

Diisocyanates (dNCOs) are potent chemical allergens utilized in various industries. It has been proposed that skin exposure to dNCOs produces immune sensitization leading to work-related asthma and allergic disease. We examined dNCOs sensitization by using a dermal murine model of toluene diisocyanate (TDI) exposure to characterize the disposition of TDI in the skin, identify the predominant haptenated proteins, and discern the associated antigen uptake by dendritic cells. Ears of BALB/c mice were dosed once with TDI (0.1% or 4% v/v acetone). Ears and draining lymph nodes (DLNs) were excised at selected time points between 1 h and 15 days post-exposure and were processed for histological, immunohistochemical, and proteomic analyses. Monoclonal antibodies specific for TDI-haptenated protein (TDI-hp) and antibodies to various cell markers were utilized with confocal microscopy to determine co-localization patterns. Histopathological changes were observed following exposure in ear tissue of mice dosed with 4% TDI/acetone. Immunohistochemical staining demonstrated TDI-hp localization in the stratum corneum, hair follicles, and sebaceous glands. TDI-hp were co-localized with CD11b(+) (integrin αM/Mac-1), CD207(+) (langerin), and CD103(+) (integrin αE) cells in the hair follicles and in sebaceous glands. TDI-hp were also identified in the DLN 1 h post-exposure. Cytoskeletal and cuticular keratins along with mouse serum albumin were identified as major haptenated species in the skin. The results of this study demonstrate that the stratum corneum, hair follicles, and associated sebaceous glands in mice are dendritic cell accessible reservoirs for TDI-hp and thus identify a mechanism for immune recognition following epicutaneous exposure to TDI.

Pulmonary immune responses to Aspergillus fumigatus in an immunocompetent mouse model of repeated exposures

Aspergillus fumigatus is a filamentous fungus that produces abundant pigmented conidia. Several fungal components have been identified as virulence factors, including melanin; however, the impact of these factors in a repeated exposure model resembling natural environmental exposures remains unknown. This study examined the role of fungal melanin in the stimulation of pulmonary immune responses using immunocompetent BALB/c mice in a multiple exposure model. It compared conidia from wild-type A. fumigatus to two melanin mutants of the same strain, Δarp2 (tan) or Δalb1 (white). Mass spectrometry-based analysis of conidial extracts demonstrated that there was little difference in the protein fingerprint profiles between the three strains. Field emission scanning electron microscopy demonstrated that the immunologically inert Rodlet A layer remained intact in melanin-deficient conidia. Thus, the primary difference between the strains was the extent of melanization. Histopathology indicated that each A. fumigatus strain induced lung inflammation, regardless of the extent of melanization. In mice exposed to Δalb1 conidia, an increase in airway eosinophils and a decrease in neutrophils and CD8(+) IL-17(+) (Tc17) cells were observed. Additionally, it was shown that melanin mutant conidia were more rapidly cleared from the lungs than wild-type conidia. These data suggest that the presence of fungal melanin may modulate the pulmonary immune response in a mouse model of repeated exposures to A. fumigatus conidia.

A murine monoclonal antibody with broad specificity for occupationally relevant diisocyanates

Diisocyanates (dNCOs) used in industrial applications are well known low molecular weight allergens. Occupational exposure is associated with adverse health outcomes including allergic sensitization and occupational asthma. In this study, we report the production and initial characterization of a dNCO-hapten specific murine IgM monoclonal antibody (mAb). Female BALB/c mice were immunized intraperitoneally with 25 μg of 4,4'-methylene diphenyl diisocyanate (MDI)-keyhole limpet hemocyanin. Following six biweekly booster immunizations, splenocytes were recovered and fused to Sp2/0-Ag14 murine myeloma cell line for hybridoma production. Hybridomas were then screened in a solid-phase indirect enzyme-linked immunosorbent assay (ELISA) against 40:1 4,4'-MDI- human serum albumin (HSA). mAb reactivity to dNCO-HSA conjugates and dNCO-HSA spiked human serum were characterized using a sandwich ELISA. One hybridoma produced a multimeric IgM mAb (15D4) that reacted with 4,4'-MDI-HSA. Sandwich ELISA analysis demonstrated comparable reactivity with other occupationally relevant dNCO-HSA adducts, including 2,4-toluene diisocyanate (TDI)-HSA, 2,6-TDI-HSA, and 1,6-hexamethylene diisocyanate (HDI)-HSA, but not other electrophilic chemical HSA conjugates. The limit of quantification (LOQ) of 4,4'-MDI-HSA, 2,4-TDI-HSA, 2,6-TDI-HSA, and 1,6-HDI-HSA sandwich ELISAs were 567.2, 172.7, 184.2, and 403.5 ng/mL (8.67, 2.60, 2.77, and 6.07 pmol/mL), respectively. In contrast, experiments using dNCO-supplemented human sera showed an increase in the detectable limit of the assay. A mAb has been produced that has potential utility for detecting mixed diisocyanate exposures in occupational environments. The mAb may have additional utility in the standardization of specific IgE detection immunoassays as well as chromatographic-mass spectrometric methods to enrich dNCO adducted HSA in the plasma of occupationally exposed workers.

Aspergillus collagen-like genes (acl): identification, sequence polymorphism, and assessment for PCR-based pathogen detection

The genus Aspergillus is a burden to public health due to its ubiquitous presence in the environment, its production of allergens, and wide demographic susceptibility among cystic fibrosis, asthmatic, and immunosuppressed patients. Current methods of detection of Aspergillus colonization and infection rely on lengthy morphological characterization or nonstandardized serological assays that are restricted to identifying a fungal etiology. Collagen-like genes have been shown to exhibit species-specific conservation across the noncollagenous regions as well as strain-specific polymorphism in the collagen-like regions. Here we assess the conserved region of the Aspergillus collagen-like (acl) genes and explore the application of PCR amplicon size-based discrimination among the five most common etiologic species of the Aspergillus genus, including Aspergillus fumigatus, A. flavus, A. nidulans, A. niger, and A. terreus. Genetic polymorphism and phylogenetic analysis of the aclF1 gene were additionally examined among the available strains. Furthermore, the applicability of the PCR-based assay to identification of these five species in cultures derived from sputum and bronchoalveolar fluid from 19 clinical samples was explored. Application of capillary electrophoresis on nanogels was additionally demonstrated to improve the discrimination between Aspergillus species. Overall, this study demonstrated that Aspergillus acl genes could be used as PCR targets to discriminate between clinically relevant Aspergillus species. Future studies aim to utilize the detection of Aspergillus acl genes in PCR and microfluidic applications to determine the sensitivity and specificity for the identification of Aspergillus colonization and invasive aspergillosis in immunocompromised subjects.