Oxatomide Inhibits Interleukin-8 Release from Respiratory Epithelial Cells*
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ORIGINAL CONTRIBUTION Oxatomide inhibits Interleukin-8 release from respiratory epithelial cells* 1 1 1 1 Hideyuki Kawauchi , Noriaki Aoi , Ichiro Morikura , Takafumi Fuchiwaki , Rhinology Online, Vol 1: 50 - 56, 2018 1 1 1 1 Yasuhiko Shimizu , Kanako Shimizu , Yukie Hotta , Qu Infei , Takaya http://doi.org/10.4193/RHINOL/18.026 Yamada2, Emmanuel Prokopakis3 *Received for publication: 1 Department of Otorhinolaryngology, Shimane University, Faculty of Medicine, Izumo City, Japan May 25, 2018 2 Department of Experimental Animals, Interdisciplinary Center for Science Research, Organization for Research, Shimane Accepted: May 29, 2018 University, Izumo city, Japan 3 Department of Otolaryngology, University of Crete School of Medicine, Heraklion, Crete, Greece Abstract Background: Oxatomide, a H1-receptor antagonist, exerts besides its well-known anti-allergic potential an array of anti-inflam- matory activities. We wondered whether oxatomide might influence the release of IL-8 from human epithelial cells activated with agonists of TLR2, which mainly expresses on airway epithelial cells. Methodology: We used the human lung epithelial cell line A549 and primary Human nasal epithelial cell line for our in vitro stu- dies. IL-8 releases from these cell lines were determined by IL-8 enzyme immunoassay. NF-kB was analysed by Luciferase reporter assay. Confluent epithelial cell monolayer were pre-incubated with oxatomide for 30 min and afterwards activated with lipopro- tein as a TLR2 agonist for 24 h. Results: Epithelial cells stimulated with lipoprotein showed a significantly increased release of IL-8. Pre-incubation with oxatomi- de diminished the IL-8 release from cells activated with lipoprotein in a significant manner. Furthermore, activity of the NF-kB was determined by luciferase reporter assy. Besides, oxatomide inhibits expression of MIP2, a homologue of human IL-8, and neutrop- hilic infiltration in nasal membrane of mice intranasally exposed with lipoprotein. These results suggest that oxatomide reduced the release of IL-8 from respiratory epithelial cells stimulated with lipoprotein. Conclusion: Therefore, oxatomide might exert anti-inflammatory effects beyond its H1-receptor antagonistic activity in the course of inflammatory respiratory tract disorders such as acute bacterial rhinitis. Key words: H1-receptor antagonists, IL-8, nasal epithelial cell, NF-kB Introduction locytes, T cells (4) and the adhesion of eosinophils to endothelial Oxatomide, a carboxylated metabolite of hydroxizine, belongs cells was inhibited (5). It has been shown that the production of to the new generation of H1-receptor antagonists (1). A positive newly generated pro-inflammatory mediators such as reactive therapeutic effect of oxatomide has been shown in allergic rhi- toxic oxygen radicals and lipid mediators from eosinophils (6), noconjunctivitis, chronic urticaria, and pollen-associated asthma basophils and mast cells (7) was counter-regulated by oxatomide. (2,3). There has also been an accumulation of evidence that oxa- Besides, LTD4 in middle ear of chinchillas with otitis media with tomide shows some anti-inflammatory activities unrelated to its effusion was reported to be suppressed by oxatomide (8). It has histamine antagonism, e.g. the chemotactic activity of granu- also been shown that epithelial cells play a crucial role during Abbreviations used in this paper: IL, Interleukin; CD, Clusters of differentiation; TRL, Toll-like receptor; FCS, Fetal calf serum; HNECs, Human nasal epi- thelial cells; HPV-16, Human papillomavirus 16; Ig, Immunoglobulin; ikBα, Inhibitor kBα; RT, Reverse transriptase; ELISA, Enzyme-linked immunosorb- ent assay; NF-kB, Nuclear Factor-kB; i.n., Intranasally; i.g., Intragastric. 50 Oxatomide inhibits Interleukin-8 release acute inflammatory and infectious processes by secreting µg/ml streptomycin, 100 IU/ml penicillin and 20 mmol/l sodium interleukin-8 (IL-8) (9-12). The multifactorial pro-inflammatory hydrogen carbonate. Normal human nasal tissues (500 mg) were cytokine IL-8, a member of the chemokine super-gene family obtained from two patients with chronic sinusitis after receiving (13), has chemotactic activity toward neutrophils as well as T informed consent from the patients. HNECs were transfected lymphocytes (14). In addition, neutrophils are activated by IL- with human papillomavirus 16 (HPV-16) E6 and E7 open reading 8,enhanced expression of Clusters of differentiation (CD) 11b/ frames. These cells were designated HNEC-1 and HNEC-2, res- CD18, transendothelial migration, generation of reactive oxygen pectively, and used between passages 50 and 60. HEK293 and products and exocytosis (15). As a direct consequence of this po- U937 as a human monocytes were obtained from ATCC. tent neutrophil-activating potential, IL-8 plays a major role in the pathogenesis of many acute inflammatory reactions, including Cell culture conditions acute rhinitis (16,17). Epithelial cells recognize microbial pathogens A549 cells, HNEC-1 and HNEC-2 were cultured at 370C in a water- by a set of germ line-encoded receptors that are referred to as saturated atmosphere containing 5% CO2. Only cell preparati- pattern-recognition receptors. Toll-like receptors (TLRs) function ons with a viability greater than 95%, determined by a trypan as the major epithelial pattern-recognition receptors in recog- blue exclusion test, were used. The buffers and cell media were nition of a pathogen-associated molecular patterns (18). Activa- prepared using pyrogen-free water. Confluent A549, HNEC-1 and tion of TLRs, in turn, leads to induction of direct antimicrobial HNEC-2 monolayers (105 cells) were cultured in 1 mL RPMI-1640 effector pathways that can result in elimination of the invading (10% FCS [v/v]) with antibiotics in 24-well plastic tissue culture pathogens (19). Activation of TLRs also induces the expression of plates (Costar, Cambridge, MA, USA). Confluent monolayers were co-stimulatory molecules and the release of IL-8 that instruct pre-incubated with oxatomide (0.01-10 μg/ml) for 30 min. After the acquired immune response (20). To date, 10 members of the pretreatment, the cells were washing with PBS twice. The range human TLR family have been cloned. Among these, TLR2 has of doses used, 0.01-10 µg/ml, corresponds to the physiologi- been shown to mediate responses to a variety of Gram-positive cal plasmatic concentration range of oxatomide. After 24 h of products, including peptidoglycan, lipoprotein, lipoteichoic acid culture, the cell supernatants were collected and stored at -70°C and lipoarabinomannan. It is clear that TLR2 plays a crucial role until IL-8 determination. in host defense against both Gram-positive and -negative bacte- ria (21,22)]. Interestingly, in the upper respiratory tract, it has been Mice reported that TLR2 is expressed dominantly in epithelial cells (23). C57BL/6 mice were purchased from Japan SLC (Shizuoka, Japan). We wondered whether IL-8 production by human epithelial cells The mice were bred in our institute under specific pathogen-free stimulated with lipoprotein via TLR2 might also be influenced by conditions. Eight- to 10-week-old female mice were used for the the H1-receptor antagonist oxatomide. We used the human pul- experiments. monary type II epithelial cell line A549 and primary Human nasal epithelial cells (HNECs) for our in vitro study. We also assessed Reverse transcription-PCR the in vivo role of oxatomide in a murine acute rhinitis model. Total cellular RNA from A549, HNEC-1, HNEC-2 and U937 was extracted with RNAzol B (Tel-Test, Friendswood, TX, USA) using Methods a single-step isolation method (25,26) according to the manufac- Reagents turer's recommendation. RNase-free DNase (Takara Biochemi- Synthetic Lipid A was provided by Ono Pharmaceutics. Synthetic cals, Shiga, Japan) was used to remove genomic DNA based on lipoprotein (palmitoyl-Cys(RS)-2,3-di(palmitoyloxy)-propyl)-Ala- methods described previously (27). Two micrograms of extracted Gly-OH)) was provided by Bachem (Bubendorf, Switzerland). RNA was reverse-transcribed into first-strand cDNA at 42°C for Anti-phospho- Inhibitor kBa (ikBa) mAb and anti-ikBa poly- 40 min using 100 U/ml of reverse transcriptase (RT) (Takara clonal Ab were obtained from New England Biolabs (Beverly, Biomedicals, Shiga, Japan) and 0.1 µM oligo(dT) adapter primer MA, USA) and Santa Cruz Biotechnology (Santa Cruz, CA, USA), (Takara Biomedicals, Shiga, Japan) in a 50-µl reaction mixture. respectively. Anti-murine MIP-2 monoclonal antibody was PCR amplification of cDNA was performed using oligonucle- purchased from Genzyme-Thecne (Techne, AN'ALYZA immuno- otide primers specific for TLR1 (Sense: 5'-AGTTGTCAGCGATG- assay system; Genzyme). TGTTCGG-3' Antisense: 5'-GATCAAGTACCTTGATCCTGGG-3', TLR2 (Sense: 5'-GGCTTCTCTGTCTTGTGACC-3' Antisense: 5'-GGGCTT- Cells GAACCAGGAAGAC G-3'), TLR3 (Sense: 5'-AGCCACCTGAAGTTG- Cells of the human A549, pulmonary epithelial cell line (ATCC ACTCAGG-3' Antisense: 5'-CAGTCAAATTCGT GCAGAAGGC-3'), CCL 185, Rockville, MD, USA) show features of type II alveolar TLR4 (Sense: 5'-TTGTATTCAAG GTCT GGCTGG-3' Antisense: epithelial cells and produce surfactants (24). The cells were grown 5'-GCAAC CTTTGAAACTCAAGCC-3'), TLR5 (Sense: 5'-AGC- in FK12 medium containing 10% (v/v) fetal calf serum (FCS), 100 CATCTG ACTGCATTAAGG-3' Antisense: 5'-GACTTCCTCTTCAT- 51 Kawauchi et al. CACAACC-3'), TLR6 (Sense: 5'-CCTG GGAGGTAAACATCTGA-3' Antisense: 5'-CCCTCAACCACATAGAAACGA-3'), TLR7 (Sense: 5'-GATAACAATGTCACAGC CGTCC-3' Antisense: 5'-GTTCCTG- GAGTTTGTTGATGTTC-3'),