Β2 Adrenergic Agonist Suppresses Eosinophil-Induced Epithelial-To- Mesenchymal Transition of Bronchial Epithelial Cells Keigo Kainuma1,2, Tetsu Kobayashi3, Corina N
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Kainuma et al. Respiratory Research (2017) 18:79 DOI 10.1186/s12931-017-0563-4 RESEARCH Open Access β2 adrenergic agonist suppresses eosinophil-induced epithelial-to- mesenchymal transition of bronchial epithelial cells Keigo Kainuma1,2, Tetsu Kobayashi3, Corina N. D’Alessandro-Gabazza2, Masaaki Toda2, Taro Yasuma2, Kota Nishihama2, Hajime Fujimoto3, Yu Kuwabara1,2, Koa Hosoki1,2, Mizuho Nagao1, Takao Fujisawa1 and Esteban C. Gabazza2* Abstract Background: Epithelial-mesenchymal transition is currently recognized as an important mechanism for the increased number of myofibroblasts in cancer and fibrotic diseases. We have already reported that epithelial- mesenchymal transition is involved in airway remodeling induced by eosinophils. Procaterol is a selective and full β2 adrenergic agonist that is used as a rescue of asthmatic attack inhaler form and orally as a controller. In this study, we evaluated whether procaterol can suppress epithelial-mesenchymal transition of airway epithelial cells induced by eosinophils. Methods: Epithelial-mesenchymal transition was assessed using a co-culture system of human bronchial epithelial cells and primary human eosinophils or an eosinophilic leukemia cell line. Results: Procaterol significantly inhibited co-culture associated morphological changes of bronchial epithelial cells, decreased the expression of vimentin, and increased the expression of E-cadherin compared to control. Butoxamine, a specific β2-adrenergic antagonist, significantly blocked changes induced by procaterol. In addition, procaterol inhibited the expression of adhesion molecules induced during the interaction between eosinophils and bronchial epithelial cells, suggesting the involvement of adhesion molecules in the process of epithelial-mesenchymal transition. Forskolin, a cyclic adenosine monophosphate-promoting agent, exhibits similar inhibitory activity of procaterol. Conclusions: Overall, these observations support the beneficial effect of procaterol on airway remodeling frequently associated with chronic obstructive pulmonary diseases. Keywords: Asthma, Eosinophils, Epithelial cells, Integrins Background the first line drug for relief of acute asthma symptoms but Obstructive pulmonary diseases such as bronchial asthma a long-term controller in combination with inhaled corti- and chronic obstructive pulmonary disease are chronic in- costeroids. Procaterol is a selective and full β2 adrenergic flammation of the airways that are frequently associated agonist that is used as a rescue of asthmatic attack in with lung structural changes, termed airway remodeling inhaler form and orally as a controller [5]. Studies [1, 2]. The pathogenesis of airway remodeling has not in vitro have shown that β2 selective-agonists exert anti- been fully elucidated. It may be a consequence of airway inflammatory activity. β2 selective-agonists increase cyclic inflammation [3, 4]. β2 adrenergic agonists are not only AMP levels, which inhibit mast cell and eosinophil de- granulation, apoptosis and cytokine production [6–9]. * Correspondence: [email protected] Procaterol can also reduce the expression of adhesion 2Department of Immunology, Mie University Graduate School of Medicine, molecules [6, 10]. A previous study has shown that sys- Edobashi 2-174, Tsu, Mie 514-8507, Japan β Full list of author information is available at the end of the article temic administration of tulobuterol, a 2-selective agonist, © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Kainuma et al. Respiratory Research (2017) 18:79 Page 2 of 11 decreases eosinophil adhesion to endothelial cells resulting Preparation of human eosinophils in reduction of eosinophil inflammation [11]. β2 adrener- Eosinophils from healthy human volunteers (age 30 to gic agonists are also very effective bronchodilators in 45 years old with no present history of any disease) were COPD and they are part of the therapeutic strategy for the purified by negative selection using anti-CD16 and anti- management of COPD patients [12, 13]. Short acting or CD14 bound micromagnetic beads as previously described long acting β2 agonists are administered in clinical practice [19]. The purity of eosinophils was more than 97% as mea- through inhaler devices whose delivery efficiency has sured by the Randoph’s phloxine-methylene blue stain [21]. substantially improved by the use of computational models [13–17]. Co-culture experiment and morphological analysis Epithelial to mesenchymal transition (EMT) leads to BEAS-2B cells were cultured in 6- or 12-well plates until increased number of myofibroblasts in cancer and fibrotic 60–70% cell confluence, then serum-starved for 24 h. diseases [18]. Eosinophils can cause airway remodeling by Eosinophils were pre-treated with procaterol (provided − promoting EMT [19]. Recently, we and others have re- by Otsuka Pharmacy) at 10 9 Mfor1h.Humaneosino- ported that direct contact of eosinophils with bronchial phils (1 × 106 cells for 12-well plate, 2 × 106 cells for 6-well epithelial cells increases the expression of TGF-β1 leading plate) were added to the culture RPMI medium and incu- to induction of EMT [20]. In the present study, we hy- bated for further 24 h. After co-culture, human eosinophils pothesized that procaterol can suppress EMT of airway were removed from adherent BEAS-2B cells by gentle pip- epithelial cells induced by eosinophils. etting. BEAS-2B cells were stained by Diff-Quick technique and photographed for analyzing morphological changes. Methods For immunofluorescence, cells were fixed with 4% parafor- Reagent maldehyde for 10 min at room temperature and stained L-glutamine, penicillin/streptomycin, donkey anti-mouse with mouse anti-E-cadherin mAb and anti α-SMA Ab IgG-Alexa Fluor 488, Chicken anti-rabbit IgG-Alexa (rabbit polyclonal) followed by the secondary antibodies Fluor 594, Laemmli sample buffer and Trizol Reagent (donkey anti-mouse IgG conjugated with AF488 and chi- were purchased from Invitrogen (Carlsbad, CA). Dulbec- ken anti-rabbit IgG conjugated with AF594. Deparaffinized co’s modified Eagle’s medium (DMEM), RPMI-1640 and tissue sections were subjected to hydrated autoclaving for bovine serum albumin (BSA) were from Sigma (St Louis, antigen retrieval. After washing with Tris-buffered saline, MO), and fetal bovine serum (FBS) from Thermo scien- slides were exposed to mouse anti–human E-cadherin anti- tific. Rabbit anti α-SMA, anti-CD16 and anti-CD14 bound body (1:200) overnight at 4 °C and subsequently incubated micromagnetic beads were purchased from Miltenyi Bio- with donkey anti-mouse IgG-Alexa Fluor 488 (1:200) for tec (Auburn, CA), mouse anti-human E-cadherin antibody 4 h at room temperature after washing. Staining of α-SMA from BD Biosciences (Mississauga, ON, Canada), and was done using rabbit anti–human α-SMA antibody anti-TGF-β1 monoclonal antibody (mAb) (1D11) from (1:200) and then chicken anti-rabbit IgG-Alexa Fluor 594 R&D Systems (Minneapolis, MN). Sepasol-RNA I super G (1:200). After washing, the sections were counterstained (Nacalai tesque), anti-mouse antibodies against CD11b with 4,6-diamidino-2-phenylindole (DAPI) and mounted (integrin αM), CD49d (integrin α4), CD29 (integrin β1), using a fluorescence mounting medium. 5 CD18 (integrin β1), CD54 (ICAM-1), and CD106 In separate experiments, human eosinophils (2 × 10 − (VCAM-1) were from BioLegend. cells) were prepared and treated with 10 7 M procaterol − or 10 5 M forskolin (Nacalai Tesque, Kyoto, Japan) for Cell lines 30 min at 37 °C. A group of eosinophils was then co- BEAS-2B, an adenovirus 12-SV40 virus hybrid (Ad12SV40) cultured with serum-starved semi-confluent BEAS-2B transformed human epithelial cells, was obtained from the cells (2.5 × 105 cells/well, 12-well plate) for 24 h and the Riken Cell Bank (Tsukuba, Japan), and cultured in DMEM cell surface expression of integrins on eosinophils was supplemented with 10% (v/v) heat-inactivated FBS, 0.03% evaluated by flow cytometry. Control eosinophils were (w/v) L-glutamine, 100 IU/ml penicillin and 100 μg/ml cultured alone for 24 h. Another group of eosinophils streptomycin. EoL-1 cells were obtained from the Riken was co-cultured with BEAS-2B cells for 48 h and the cell Cell Bank, maintained in suspension culture at 37 °C and supernatants and adherent cells (BEAS-2B cells) were 5%CO2 in humidified atmosphere using RPMI-1640 collected for analysis of cytokine expression by RT-PCR medium supplemented with 10%(v/v) heat-inactivated FBS, and immunoassays. 0.03%(w/v) L-glutamine, 100 IU/ml penicillin and 100 μg/ ml streptomycin. For differentiation, EoL-1 cells were di- Reverse transcriptase polymerase chain reaction (RT-PCR) luted to 5 × 105 cells/ml and 0.5 mM sodium n-butyrate After co-culture of BEAS-2B cells and eosinophils for (BA) was added. EoL-1 cells were incubated with 0.5 mM 24 h, eosinophils were removed as described above. BA for 5 days. Total RNA was extracted from BEAS-2B cells by the Kainuma et al. Respiratory Research (2017) 18:79 Page 3 of 11 guanidine isothiocyanate procedure using Trizol Reagent. out at 72 °C for 5 min. The PCR products were sepa- RNA was reverse-transcribed using oligo-dT primers and rated on a 2% agarose gel containing 0.01% ethidium then the DNA was amplified by PCR. The sequences of bromide. The RNA concentration and purity were deter- the primers are as follows: for human vimentin, forward mined by UV absorption at 260:280 using an Ultrrospec 5′-GAGAACTTTGCCGTTGAAGC-3′ and reverse 5′- 1100 pro UV/Vis spectrophotometer (Amersham Biosci- GCTTCCTGTAGGTGGTGGCAATC-3′;forhuman ences, NJ). The amount of mRNA was normalized against E-cadherin forward: 5′-GTATCTTCCCCGCCCTGCC the GAPDH mRNA.