Cystic fibrosis isolates have been found to attenuate virulence factor expression as part of immune evasion strategies in chronic infection [44]

Cystic fibrosis isolates have been found to attenuate virulence factor expression as part of immune evasion strategies in chronic infection [44]. with 10 M Y27632. The cells were stained for F-actin with Phalloidin. Green: Phalloidin, blue: H?chst, bar: 10 m.(TIFF) pone.0056491.s003.tiff (2.3M) GUID:?AAA468CE-EC06-40A3-B9C5-B68590A26256 Abstract is an opportunistic pathogen commonly associated with lung and wound infections. Hypoxia is usually a frequent feature of the microenvironment of infected tissues which induces the expression of genes associated with innate immunity and inflammation in host cells primarily through the activation of the hypoxia-inducible factor (HIF) and Nuclear factor kappaB (NF-B) pathways which are regulated by oxygen-dependent prolyl-hydroxylases. Hypoxia also affects virulence and antibiotic resistance in bacterial pathogens. However, less is known about the impact of hypoxia on host-pathogen interactions such as bacterial adhesion and contamination. In the current study, we demonstrate that hypoxia decreases the internalization of into cultured epithelial cells resulting in decreased host cell death. This response can also be elicited by the hydroxylase inhibitor Dimethyloxallyl Glycine (DMOG). Reducing HIF-2 expression or Rho kinase activity diminished the effects CD209 of hypoxia on contamination. Furthermore, in an in vivo pneumonia contamination model, application of DMOG 48 h before contamination with significantly reduced mortality. Thus, hypoxia reduces internalization into epithelial cells and pharmacologic manipulation of the host pathways involved BOC-D-FMK may represent new therapeutic targets in the treatment of contamination. Introduction Lower respiratory tract infections are the leading cause of death among infectious diseases. Pulmonary contamination with associated intra-alveolar exudates, edematous septal thickening and multiplying pathogens inhibit oxygen diffusion and result in decreased mucosal oxygenation leading to dysregulated gas exchange. is one of the major pathogens encountered in nosocomial infections causing severe lower respiratory tract infections, skin and soft tissue infections (especially in burn patients) and bacteremia in patients with leukemia, cancer or other immunosuppressive states. In addition is the main respiratory pathogen encountered in cystic fibrosis where it is associated with increased morbidity and mortality [1]. Hypoxia has been exhibited in mucus filled airways of cystic fibrosis patients [2]. Treatment of infections is complicated by rising antimicrobial resistance, absence of an effective vaccine and by the lack of newer antimicrobial brokers in development. Prominent regions of hypoxia are common features of infected and inflamed tissues [3], [4]. In infected tissues, oxygen consumption by bacterial pathogens and phagocytes exacerbates tissue hypoxia. Hypoxia is an important driver of innate immune and inflammatory gene expression in host cells through the activation of transcription BOC-D-FMK factors including Nuclear Factor kappaB (NF-B) and the Hypoxia inducible factor (HIF) [5], [6], [7]. Furthermore, it has recently become clear that hypoxia can also influence the expression of virulence and antibiotic resistance genes in invading pathogens such BOC-D-FMK as and species respectively [8], [9]. However, despite the recognition that hypoxia independently affects both host and pathogen, less is known about how it impacts upon host-pathogen interactions such as adhesion and contamination. The Hypoxia inducible factor (HIF) is usually a grasp regulator of gene expression in metazoan cells exposed to hypoxia [10], [11]. HIF consists of an oxygen-sensitive -subunit and a constitutively expressed -subunit. One of three isoforms of the HIF -subunit bound to a single isoform of the HIF -subunit constitutes dimeric HIF-1, HIF-2 or HIF-3 respectively [12]. HIF-1 and HIF-2 positively regulate the expression of discreet but overlapping cohorts of genes and demonstrate differential temporal dynamics [13]. HIF-3 is usually a negative regulator of HIF-1 and HIF-2 [14]. In the presence of sufficient oxygen (normoxia), HIF- is usually degraded via hydroxylation BOC-D-FMK by prolyl-hydroxylases (PHD) leading to ubiquitination by the von Hipple Lindau E3 ligase and degradation by the 26S proteasome [12]. The inhibition of the oxygen-dependent prolyl-hydroxylases in hypoxia leads to HIF stabilisation/transactivation with subsequent activation of HIF-dependent target genes. Three PHD isoforms have BOC-D-FMK been identified to date. Among these, normoxic HIF-1 degradation.