The research described in this thesis focuses on the responses of lung epithelial cells lining the airways and alveoli. In the study, the effects of viruses that cause lung infections on these... Show moreThe research described in this thesis focuses on the responses of lung epithelial cells lining the airways and alveoli. In the study, the effects of viruses that cause lung infections on these epithelial cells were mapped in detail. Combinations with exposure to cigarette smoke were also included. To do this, epithelial cells obtained from lung tissue were cultured in the lab and exposed to rhinovirus, a common cold virus, and to SARS-CoV-2, which causes COVID-19. Exposure of the epithelial cells to these viruses induces very specific reactions in the airway epithelium. These can be further affected by cigarette smoke. The results of our research have taught us more about the processes specifically involved in the different responses of the epithelium, and how external factors such as cigarette smoke influence these responses. For example, we now better understand how cigarette smoke leads to a higher infection rate of rhinovirus, and it has become clear that the response of the airway epithelium to SARS-CoV-2 differs from the response to other coronaviruses. Our findings are therefore important for a better understanding of the role of viral infections in patients with chronic obstructive pulmonary disease (COPD), and for understanding what makes SARS-CoV-2 a unique virus. Show less
Riet, S. van; Schadewijk, A. van; Vos, S. de; Vandeghinste, N.; Rottier, R.J.; Stolk, J.; ... ; Khedoe, P. 2020
Airway epithelial cells and macrophages participate in inflammatory responses to external noxious stimuli, which can cause epithelial injury. Upon injury, epithelial cells and macrophages act in... Show moreAirway epithelial cells and macrophages participate in inflammatory responses to external noxious stimuli, which can cause epithelial injury. Upon injury, epithelial cells and macrophages act in concert to ensure rapid restoration of epithelial integrity. The nature of the interactions between these cell types during epithelial repair is incompletely understood. We used an in vitro human coculture model of primary bronchial epithelial cells cultured at the air-liquid interface (ALI-PBEC) and polarized primary monocyte-derived macrophages. Using this coculture, we studied the contribution of macrophages to epithelial innate immunity, wound healing capacity, and epithelial exposure to whole cigarette smoke (WCS). Coculture of ALI-PBEC with lipopolysaccharide (LPS)-activated M(GM-CSF) macrophages increased the expression ofDEFB4A,CXCL8, andIL6at 24 h in the ALI-PBEC, whereas LPS-activated M(M-CSF) macrophages only increased epithelialIL6expression. Furthermore, wound repair was accelerated by coculture with both activated M(GM-CSF) and M(M-CSF) macrophages, also following WCS exposure. Coculture of ALI-PBEC and M(GM-CSF) macrophages resulted in increasedCAMPexpression in M(GM-CSF) macrophages, which was absent in M(M-CSF) macrophages.CAMPencodes LL-37, an antimicrobial peptide with immune-modulating and repair-enhancing activities. In conclusion, dynamic crosstalk between ALI-PBEC and macrophages enhances epithelial innate immunity and wound repair, even upon concomitant cigarette smoke exposure. Show less
Airway epithelium is an important site for local vitamin D (VD) metabolism; this can be negatively affected by inflammatory mediators. VD is an important regulator of respiratory host defense, for... Show moreAirway epithelium is an important site for local vitamin D (VD) metabolism; this can be negatively affected by inflammatory mediators. VD is an important regulator of respiratory host defense, for example, by increasing the expression of hCAP18/LL-37. TGF-beta 1 is increased in chronic obstructive pulmonary disease (COPD), and known to decrease the expression of constitutive host defense mediators such as secretory leukocyte protease inhibitor (SLPI) and polymeric immunoglobulin receptor (pIgR). VD has been shown to affect TGF-beta 1-signaling by inhibiting TGF-beta 1-induced epithelial-to-mesenchymal transition. However, interactions between VD and TGF-beta 1, relevant for the understanding host defense in COPD, are incompletely understood. Therefore, the aim of the present study was to investigate the combined effects of VD and TGF-beta 1 on airway epithelial cell host defense mechanisms. Exposure to TGF-beta 1 reduced both baseline and VD-induced expression of hCAP18/LL-37, partly by increasing the expression of the VD-degrading enzyme CYP24A1. TGF-beta 1 alone decreased the number of secretory club and goblet cells and reduced the expression of constitutive host defense mediators SLPI, s/lPLUNC and pIgR, effects that were not modulated by VD. These results suggest that TGF-beta 1 may decrease the respiratory host defense both directly by reducing the expression of host defense mediators, and indirectly by affecting VD-mediated effects such as expression of hCAP18/LL-37. Show less
Does, A.M. van der; Heijink, M.; Mayboroda, O.A.; Persson, L.J.; Aanerud, M.; Bakke, P.; ... ; Giera, M. 2019
Introduction: Disturbances in onset and resolution of inflammation in chronic obstructive pulmonary disease (COPD) are incompletely understood. Dietary polyunsaturated fatty acids (PUFAs) can be... Show moreIntroduction: Disturbances in onset and resolution of inflammation in chronic obstructive pulmonary disease (COPD) are incompletely understood. Dietary polyunsaturated fatty acids (PUFAs) can be converted into lipid mediators here collectively named oxylipins. These include classical eicosanoids, but also pro-resolving mediators. A balanced production of pro-inflammatory and pro-resolving oxylipins is of importance for adequate inflammatory responses and subsequent return to homeostasis.Objectives: Here we investigated if PUFA metabolism is disturbed in COPD patients.Methods: Free PUFA and oxylipin levels were measured in induced sputum samples from the Bergen COPD cohort and COPD exacerbation study using liquid chromatography-mass spectrometry. Additionally, effects of whole cigarette smoke on PUFA metabolism in air-liquid interface cultures of primary bronchial epithelial cells were assessed.Results: Significantly lower levels of free alpha-linolenic acid, linoleic acid and eicosapentaenoic acid (EPA) were detected in sputum from stable COPD patients compared to controls. During acute exacerbation (AE), levels of free arachidonic acid and docosapentaenoic acid were higher than in stable COPD patients. Furthermore, levels of omega-3 EPA- and docosahexaenoic acid-derived oxylipins were lower in sputum from stable COPD patients compared to controls. Cyclooxygenase-2-converted mediators were mostly increased during AE. In vitro studies additionally showed that cigarette smoke exposure may also directly contribute to altered epithelial PUFA metabolism, and indirectly by causing airway epithelial remodelling.Conclusions: Our findings show significant differences in PUFA metabolism in COPD patients compared to controls, further changed during AE. Airway epithelial remodelling may contribute to these changes. These findings provide new insight in impaired inflammatory resolution in COPD. Show less
The disease is characterized by a progressive and largely irreversible decline in lung function, which is associated with long-term airway exposures to cytotoxic particles and gasses, such as... Show moreThe disease is characterized by a progressive and largely irreversible decline in lung function, which is associated with long-term airway exposures to cytotoxic particles and gasses, such as cigarette smoke. Microbial colonization and infections are an important pathophysiological aspect in COPD patients. However, the underlying mechanisms linking smoking with microbial colonization and infections in COPD are incompletely understood. The airway epithelium is the first target of inhaled cigarette smoke. Furthermore, epithelial cells are the first defense lining of the respiratory tract that prevents microbial colonization and infections. Therefore, alterations in host defense and airway epithelial remodeling may contribute to COPD development and progression. In this thesis, studies are presented in which the impact of cigarette smoke exposure and COPD disease status on the innate host defense functions of the airway epithelium are explored. This was done by using cell culture experiments in which the effect of cigarette smoke was examined, or in which epithelial cultures of COPD patients and non-COPD (ex)smokers were compared. Show less
The studies presented in this thesis were aimed at developing and using in vitro models that could benefit research towards understanding asthma and COPD. We used an in vitro model... Show moreThe studies presented in this thesis were aimed at developing and using in vitro models that could benefit research towards understanding asthma and COPD. We used an in vitro model representing a Th2-high gene signature and studied how this gene signature may be affected by external factors such as cigarette smoke or drugs. Using these in vitro models may help to predict clinical outcomes, although they will require extensive validation. We also investigated the possibility of using primary human airway epithelial cells to model bacterial and viral exacerbations. Whereas this model is currently still under investigation, it could be particularly useful to study possible biomarkers of exacerbations and how these may be affected by external factors. Additionally, we also developed a new method to expand and differentiate mouse tracheal epithelial cells in vitro. Overall, studying airway epithelial cells may provide important clues for understanding disease pathogenesis, lead to identification of new treatment targets, and may provide important biomarkers. Using airway epithelial cells and their derived biomarkers could significantly improve our understanding in disease phenotypes of asthma and COPD. Additionally, with increasing knowledge of the disease phenotypes, we could better address the unmet need in treatment of asthma and COPD. Show less
