Novel antiviral properties of azithromycin in cystic fibrosis airway epithelial cells

Abstract

Virus-associated pulmonary exacerbations, often associated with rhinoviruses (RVs), contribute to cystic fibrosis (CF) morbidity. Currently, there are only a few therapeutic options to treat virus-induced CF pulmonary exacerbations. The macrolide antibiotic azithromycin has antiviral properties in human bronchial epithelial cells. We investigated the potential of azithromycin to induce antiviral mechanisms in CF bronchial epithelial cells.Primary bronchial epithelial cells from CF and control children were infected with RV after azithromycin pre-treatment. Viral RNA, interferon (IFN), IFN-stimulated gene and pattern recognition receptor expression were measured by real-time quantitative PCR. Live virus shedding was assessed by assaying the 50% tissue culture infective dose. Pro-inflammatory cytokine and IFN-β production were evaluated by ELISA. Cell death was investigated by flow cytometry.RV replication was increased in CF compared with control cells. Azithromycin reduced RV replication seven-fold in CF cells without inducing cell death. Furthermore, azithromycin increased RV-induced pattern recognition receptor, IFN and IFN-stimulated gene mRNA levels. While stimulating antiviral responses, azithromycin did not prevent virus-induced pro-inflammatory responses.Azithromycin pre-treatment reduces RV replication in CF bronchial epithelial cells, possibly through the amplification of the antiviral response mediated by the IFN pathway. Clinical studies are needed to elucidate the potential of azithromycin in the management and prevention of RV-induced CF pulmonary exacerbations. @ERSpublications Azithromycin reduces rhinovirus load in CF bronchial cells, possibly through the induction of the interferon pathway

Vitamin D represses rhinovirus replication in cystic fibrosis cells by inducing LL-37

“…The clinical characteristics of the study participants are shown in tables 1 and 2. Data of cells of CF patients 1-11, which have been recruited for this study, were published previously [21]. CF patients 12-17 were additionally recruited to perform the recombinant LL-37 treatment experiment only.…”

“…Cell culture and rhinovirus propagation Submerged primary CF and control bronchial epithelial cells were obtained and grown in bronchial epithelial growth medium (Lonza, Switzerland) as previously described [21]. Major group RV16 stock from species A (American Type Culture Collection, Manassas, VA, USA) was grown and titrated on Ohio-HeLa cells (European Collection of Cell Cultures, Salisbury, UK) at 2.5×10 7 TCID50-mL −1 (median tissue culture infective dose) as previously described [22].…”

“…Quantitative RT-PCR was performed by using 2 μL of cDNA and 18 μL of Taqman Fast universal PCR master mix (Thermo Fisher Scientific, Waltham, MA, USA) containing specific primers (20 μM) and probes (5 μM) for 18S [21], RV (intracellular viral RNA) [21], interferon (IFN) λ2/3 [21], viperin (virus inhibitory protein, endoplasmic reticulum-associated, interferon-inducible), Toll-like receptor 3 (TLR3) : as defined by [20]; § : present in bronchoalveolar lavage fluid at time of brushing.…”

“…[21], retinoic acid inducible gene I (RIG-I) [21], melanoma differentiation-associated protein 5 (MDA5) [21], β-defensin 2 (forward primer: 5′-ACAAATTGGCACCTGTGGTCT-3′; reverse primer: 5′-GCAGCT-TCTTGGCCTCTC-3′; probe: 5′-FAM-CCTGGAACAAAATGCTGCAAAAGCC-TAMRA-3′) [23] and LL-37 (forward primer: 5′-CATCGATTTCTTCCCTGTGAA-3′; reverse primer: 5′-TCTTGGAGCTTATT-AAAGGCATTC-3′; probe 5′-FAM-ACAAGAGCAAGGCCGTGGAGCA-TAMRA-3′) [24]. PCR reactions were carried out on a 7500 fast Real-Time PCR System (Thermo Fisher Scientific).…”

Novel approaches to the management of noneosinophilic asthma

“…The mechanism of action of macrolides in the treatment of airway diseases is not known, but could be due to antibacterial or anti-inflammatory actions, which include inhibition of nuclear factor (NF)-κB and other transcription factors as well as reduction in neutrophil migration or function [Culic et al 2001;Fujitani and Trifilieff, 2003;Simpson et al 2008;Cameron et al 2012;Kobayashi et al 2013]. Macrolides have additional potentially beneficial properties including antiviral actions [Gielen et al 2010;Schögler et al 2015] and an ability to restore corticosteroid sensitivity by inhibiting the phosphoinositide 3-kinase (PI3K) pathway and restoring histone deacetylase (HDAC)2 activity [Spahn et al 2001;Kobayashi et al 2013;Hao et al 2015] and by attenuating TNFα and IL-17 immune responses [Essilfie et al 2015]. Two recent exploratory clinical trials have investigated the effects of macrolides in noneosinophilic asthma.…”