Assessing susceptibility for polycyclic aromatic hydrocarbon toxicity in an in vitro 3D respiratory model for asthma
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ABSTRACT: There is increased emphasis on understanding cumulative risk from the combined effects of chemical and non-chemical stressors as it relates to public health. Recent animal studies have identified pulmonary inflammation as a possible modifier and risk factor for chemical toxicity in the lung after exposure to inhaled pollutants; however, little is known about specific interactions and potential mechanisms of action. In this study, primary human bronchial epithelial cells (HBEC) cultured in 3D at the air-liquid interface (ALI) are utilized as a physiologically relevant model to evaluate the effects of inflammation on toxicity of polycyclic aromatic hydrocarbons (PAHs), a class of contaminants generated from incomplete combustion of fossil fuels. Normal HBEC were differentiated in the presence of IL-13 for 14 days to induce a profibrotic phenotype similar to asthma. Fully differentiated normal and asthmatic phenotype HBEC were treated with benzo[a]pyrene (BAP; 1 – 40 ug/mL) or 1% DMSO/PBS vehicle at the ALI for 48 hrs. Cells were evaluated for cytotoxicity, barrier integrity, and transcriptional biomarkers of chemical metabolism and inflammation by quantitative PCR. Cells with the asthmatic phenotype treated with BAP show some significant (p<0.05) increase in cytotoxicity and significantly (p<0.05) decreased barrier integrity compared to normal cells. Asthmatic phenotype cells also showed increase sensitivity to BAP metabolism compared to cells with the normal phenotype. Additionally, RNA sequencing data showed that a large number of genes were uniquely significantly expressed in cells with the induced asthmatic phenotype exposed to BAP. Future studies will further explore mechanisms of toxicity from global transcriptomics and investigate the role of microRNA in mediating mechanisms of toxicity and inflammation. These data are the first to evaluate the role of combined environmental factors associated with inflammation from pre-existing disease and PAH exposure on pulmonary toxicity in a physiologically relevant human in vitro model.
Project description:In this study, we assess potential differences in mechanism of action for two PAHs, benzo[a]pyrene (BAP) and dibenzo-[def,p]chrysene (DBC), in a primary human 3D bronchial epithelial culture (HBEC) model based on short-term biosignatures identified from global transcriptional profiling.
Project description:In this study, we assess potential differences in mechanism of action for two PAHs, benzo[a]pyrene (BAP) and dibenzo-[def,p]chrysene (DBC), in a primary human 3D bronchial epithelial culture (HBEC) model based on short-term biosignatures identified from global transcriptional profiling.
2020-03-18 | GSE128471 | GEO
Project description:ChIP-seq of TRRAP in HBEC ALI cultures
Project description:Purpose: For humans, inhalation is considered as the main exposure route to chemicals, which is the reason why lung toxicity studies should be considered as a priority. Inhalation studies are often performed in vivo in rodents. Therefore, in vitro models may represent a valid and efficient alternative to predict the acute toxicity effects of inhaled chemicals on human health. The models used in this study are really simple in vitro systems either constituted by THP1 alone or THP1 cocultured with A549. This special designed has the purpose to study the impact of cellular cross talk on the THP 1 immune cells when exposed to a chemical which is BaP in the present work. Results: We describe the effects after 48 hours of exposure BaP in order to evaluate the importance of the cellular crosstalk in cell sensitivity toxicological effects of BaP. The set of parameters used to assess this cellular crosstalk included transcriptomics, cell imaging and enzymatic activity. The exposure did not cause any significant decrease of viability; all the parameters revealed the toxicity of the BaP. Regarding the global transcript, among differentially expressed genes (DEG) were found genes related to the enhancement of immune cells. Conclusion: Coculture in the used of in vitro model drastically change the gene expression profile in THP1 cells, but similar effects were observed between the monoculture and the culture exposed to BaP. However the number of altered mechanism in the THP1 cocultured cells exposed to BaP was larger supporting the importance to take into account the cell interactions.
Project description:Benzo[a]pyrene (BaP) is a product of combustion and is an abundant constituent of wildfire derived smoke and particulate matter 2.5 (PM2.5). Although arrythmias are associated with wildfire, the mechanism remains unclear. We hypothesized that BaP might predispose individuals to arrhythmias and possibly sudden cardiac death. Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) from healthy donors (n=3) were used to investigate the cardiovascular toxicity of BaP. Across a broad concentration range, BaP did not affect iPSC-CM viability, and a 4-day exposure of BaP at 50 M did not affect contractility. After exposure to BaP at 50 M for 5 days, iPSC-CMs were subjected to bulk RNA sequencing, and analysis revealed markers of inflammation were upregulated, and ion channel expression was modulated. Because inflammation is associated with reactive oxygen species (ROS) production, iPSC-CMs exposed to BaP had a concentration-dependent increase in ROS production. Mitotracker fluorescent imaging revealed decreased mitochondrial membrane potentials after iPSC-CMs treatment with 50 μM BaP. Seahorse assays revealed that BaP exposure decreased oxygen consumption rate, basal respiration, and maximal respiration in a dose-dependent manner. Using multiple electrode array (MEA) assays, iPSC-CMs exposed to 50 M BaP for 3 days, had prolonged field potential duration (FPD) and increased beat period (BP). However, co-treatment with N-acetyl cysteine (NAC), a nucleophile that scavenges ROS and preserves glutathione, attenuated the effect of BaP on FPD and BP (p<0.001). In summary, BaP exposure upregulated inflammatory cytokines and increased ROS production by impairing mitochondrial function. BaP had proarrhythmic effects of increased BP and FPD and was abrogated by NAC. Thus, BaP inhalation from wildfire smoke may predispose individuals to QT prolongation, arrhythmia, and sudden cardiac death.
Project description:The human airways are complex structures with important interactions between cells, extracellular matrix proteins and the biomechanical microenvironment. A robust, well-differentiated in vitro culture system that accurately models these interactions would provide a useful tool for studying normal and pathological airway biology. Here, we report the analysis of a physiologically relevant air-liquid interface (ALI) 3D airway ‘organ tissue equivalent’ (OTE) model with three novel features: native pulmonary fibroblasts, solubilized lung extracellular matrix (ECM), and hydrogel substrate with tunable stiffness and porosity. We demonstrate the versatility of the OTE model by evaluating the impact of these features on HBE cell phenotype. Variations of this model were analyzed during 28 days of ALI culture by evaluating epithelial confluence, trans-epithelial resistance (TEER), and epithelial phenotype via multispectral immuno-histochemistry and next-generation sequencing (NGS). Cultures that included both solubilized lung ECM and native pulmonary fibroblasts within the hydrogel substrate formed well differentiated ALI cultures that maintained a barrier function and expressed similar levels of goblet, club and ciliated markers to native airway tissue. Modulation of hydrogel stiffness did not negatively impact HBE differentiation and could be a valuable variable to alter epithelial phenotype. This study highlights the capability and versatility of a 3D airway OTE model to model the multiple components of the human airway 3D microenvironment.
Project description:Chronic obstructive pulmonary disease (COPD) has the highest increased risk due to household air pollution arising from biomass fuel burning. However, knowledge on COPD patho-mechanisms is mainly limited to tobacco smoke exposure. In this study, a repeated direct wood smoke (WS) exposure was performed using normal- (bro-ALI) and chronic bronchitis-like bronchial (bro-ALI-CB), and alveolar (alv-ALI) lung mucosa models at air-liquid interface (ALI) to assess broad toxicological end points. The bro-ALI and bro-ALI-CB models were developed using human primary bronchial epithelial cells and the alv-ALI model was developed using a representative type-II pneumocyte cell line. The lung models were exposed to WS (10 minutes/exposure; 5-exposures over 3-days; n=6-7 independent experiments). Sham exposed samples served as control. WS composition was analyzed following passive sampling. Cytotoxicity, total cellular reactive oxygen species (ROS) and stress responsive NFkB were assessed by flow cytometry. WS exposure induced changes in gene expression were evaluated by RNA-seq (p≤0.01) followed by pathway enrichment analysis. Secreted levels of proinflammatory cytokines were assessed in the basal media. Non-parametric statistical analysis was performed. 147 unique compounds were annotated in WS of which 42 compounds have inhalation toxicity (9 very high). WS exposure resulted in significantly increased ROS in bro-ALI (11.2%) and bro-ALI-CB (25.7%) along with correspondingly increased NFkB levels (bro-ALI: 35.6%; bro-ALI-CB: 18.1%). A total of 1262 (817-up and 445-down), 329 (141-up and 188-down), and 102 (33-up and 69-down) genes were differentially regulated in the WS-exposed bro-ALI, bro-ALI-CB, and alv-ALI models respectively. The enriched pathways included the terms acute phase response, mitochondrial dysfunction, inflammation, oxidative stress, NFkB, ROS, xenobiotic metabolism of AHR, and chronic respiratory disorder. The enrichment of the ‘cilium’ related genes was predominant in the WS-exposed bro-ALI (180-up and 7-down). The pathways primary ciliary dyskinesia, ciliopathy, and ciliary movement were enriched in both WS-exposed bro-ALI and bro-ALI-CB. Interleukin-6 and tumor necrosis factor-α were reduced (p<0.05) in WS-exposed bro-ALI and bro-ALI-CB.
Project description:In this research, we used MeDIP-sequencing technology to detect genome-wide methylation changes in benzo[a]pyrene(BaP)-exposed zebrafish larvae. We identified differentially methylated genes are associated with many diseases, including development of brain, and central nervous system.This high-throughput sequencing could help us to understand new mechanisms of BaP toxicity.
Project description:The present study was aimed to evaluate the protective effects of six different polyphenols against benzo(a)pyrene (BaP)-induced cytotoxicity in Caco-2 cells. The results shows that treatment of quinic acid, ferulic acid, homovanillic acid and BaP decreased the cell viability, whereas only co-treatment of 20 µM eriodictyol and naringenin reduced BaP-induced cytotoxicity, including cell apoptosis, cell cycle change and oxidative stress. Moreover, all results show that the inhibitory effect of eriodictyol was better than that of naringenin. Further, the potential protective mechanism of eriodictyol against BaP-induced toxicity was investigated by proteomics. We found that the genetic information processing pathway involves in 80 differentially expressed proteins (DEPs) showed the highest proportion and number of total proteins. Finally, eriodictyol inhibited BaP-induced cytotoxicity by regulating the expression of key proteins such as RPA2, SNRPA, RAD23B, NUP155 and AARS in transcription and translation. Overall, our results provide a new perspective for polyphenols inhibiting BaP-induced carcinogenesis.