Xenobiotic metabolism in differentiated human bronchial epithelial cells

Abstract

Differentiated human bronchial epithelial cells in air liquid interface cultures (ALI-PBEC) represent a promising alternative for inhalation studies with rodents as these 3D airway epithelial tissue cultures recapitulate the human airway in multiple aspects, including morphology, cell type composition, gene expression and xenobiotic metabolism. We performed a detailed longitudinal gene expression analysis during the differentiation of submerged primary human bronchial epithelial cells into ALI-PBEC to assess the reproducibility and inter-individual variability of changes in transcriptional activity during this process. We generated ALI-PBEC cultures from four donors and focussed our analysis on the expression levels of 362 genes involved in biotransformation, which are of primary importance for toxicological studies. Expression of various of these genes (e.g., GSTA1, ADH1C, ALDH1A1, CYP2B6, CYP2F1, CYP4B1, CYP4X1 and CYP4Z1) was elevated following the mucociliary differentiation of airway epithelial cells into a pseudo-stratified epithelial layer. Although a substantial number of genes were differentially expressed between donors, the differences in fold changes were generally small. Metabolic activity measurements applying a variety of different cytochrome p450 substrates indicated that epithelial cultures at the early stages of differentiation are incapable of biotransformation. In contrast, mature ALI-PBEC cultures were proficient in the metabolic conversion of a variety of substrates albeit with considerable variation between donors. In summary, our data indicate a distinct increase in biotransformation capacity during differentiation of PBECs at the air–liquid interface and that the generation of biotransformation competent ALI-PBEC cultures is a reproducible process with little variability between cultures derived from four different donors.Electronic supplementary materialThe online version of this article (doi:10.1007/s00204-016-1868-7) contains supplementary material, which is available to authorized users.

Human lung epithelial cell cultures for analysis of inhaled toxicants: Lessons learned and future directions

“…We recently showed that the ALI-differentiated cultures used in our laboratory for exposures to e.g. diesel exhaust (Zarcone et al, 2016;Zarcone et al, 2017) or cigarette smoke (Amatngalim et al, 2015;Amatngalim et al, 2017) show higher expression of various genes involved in biotransformation compared to undifferentiated cultures (Boei et al, 2016). Furthermore, we showed that undifferentiated cultures, in contrast to differentiated cultures, are incapable of metabolic conversion of a variety of different p450 substrates.…”

“…Expression of CYP isoenzymes may be modulated in disease and is affected by e.g. epithelial differentiation (Boei et al, 2016), which may help to explain the differential susceptibility of patients with lung diseases and healthy subjects to inhaled irritants and toxicants. Therefore, cellular differentiation and disease state should be taken into account when developing a model.…”

Complex immune responses and molecular reactions to pathogens and disease in a desert reptile (Gopherus agassizii)

“…Previous studies on diseased tortoises found that nasal discharge reduced the sense of smell and hence the ability to locate food (Germano, Zerr, Esque, Nussear, & Lamberski, ). It is also plausible that levels of transcription were also modulated by environmental or behavioral factors that were not addressed in this study (Boei et al, ). We did not quantify the activity levels, internal body temperatures, or metabolic rates for individual tortoises, but realize that temperature changes can have profound effects on metabolism and immunity by modulating important triggers and regulators of immune pathways (Ferguson, Kortet, & Sinclair, ; Sandmeier, Weitzman, & Tracy, ).…”

“…For example, RNA interference (RNAi), morpholinos, chemical inhibitors and hypomorphic mutations often lead to partial suppression of gene function, whereas null mutations can ablate gene function (Housden et al, 2017). We also know that a host of other factors such as age (Zhang, Drake, Morrison, Oberley, & Kregel, 2002), metabolism (Boei et al, 2017), prior exposure (Louis, Bhagooli, Kenkel, Baker, & Dyall, 2017), and environmental condition (Mangino, Roederer, Beddall, Nestle, & Spector, 2017) can influence these processes. Although pinpointing the specific mechanisms that may control transcription activity in our diseased tortoises is beyond the scope of this paper, our findings provide an opportunity to further explore this phenomenon and highlight the counterintuitive physiological responses often observed in tortoises and other reptiles during disturbance events (authors unpublished work; Sandmeier et al, 2016;Theodorakis et al, 2017).…”

Stem cell-based Lung-on-Chips: The best of both worlds?

“…Xenobiotic-metabolizing cytochrome P450 enzymes expressed in bronchial and bronchiolar epithelium, club cells, type II alveolar cells, and alveolar macrophages in human lung activate environmental chemicals, modifying cell biochemical microenvironment and contributing to pathologies such as cancer and COPD [86]. Expression and activity of such enzymes is in part determined by epithelial differentiation, indicating the need for appropriate cellular differentiation in models [87]. Organs-on-Chips offer the possibility to accurately control the regional and temporal biochemical microenvironment of cells through controlled perfusion of growth medium and gases.…”