[COPD Update 2015: Cell Biology goes Clinic? - Important Research Findings for Clinicians]

The COPD is a very common, chronic, non-contagious disease causing high mortality as well as high socio-economical costs worldwide. Its clinical assessment progressively becomes more comprehensive including the lung function, the rate of exacerbations, the physical capacity, the sensation of dyspnoea, and comorbidities. On the other hand, our therapeutic options are very limited: Although there are several well-tolerated and effective combinable bronchodilators of the group of long-acting beta2-mimetics and anticholinergics, drugs causally affecting pathophysiology are barely available. As anti-inflammatory principles only inhaled glucocorticoids as well as one orally available inhibitor of phosphodiesterase 4 are approved, each improving the course of disease in a subgroup of patients. This lack of effective causative therapeutic principles on the one hand and of biomarkers clearly stratifying patients on the other hand to a large extend are caused by our limited understanding of the pathophysiology. Therefore, this review presents the current progress in clinical and experimental research on COPD with regard to clinical practice.

Molecular quantification of canine specific microRNA species

MicroRNAs (miRNAs) belong to the heterogeneous group of non-coding, regulatory RNA molecules. They play an important role in physiological functions, especially during tissue development. Moreover, their cell-type specific expression levels are also thought to be altered in association with different pathological conditions, including metabolic disorders and cancer. However, the vast majority of molecular assays for their quantification have been established for humans and mice, with no reports on specific research tools for dogs. Here canine-specific SYBRGreen based quantitative, real-time PCR assays are introduced for the quantification of 21 miRNAs and five small nucleolar RNA (snoRNA). The assay includes a time-saving and economical universal one-tube cDNA synthesis approach which allows for a more robust relative quantification than the commonly used multiple specific reverse transcriptions. GeNorm and NormFinder analysis were used for the evaluation of potential housekeeping genes and identified miRNAs to be more stable housekeeping genes by trend.

Legionella pneumophila-induced IκBζ-dependent expression of interleukin-6 in lung epithelium

Severe community- and hospital-acquired pneumonia is caused by Legionella pneumophila. Lung airway and alveolar epithelial cells comprise an important sentinel system in airborne infections. Although interleukin (IL)-6 is known as a central regulator of the immune response in pneumonia, its regulation in the lung is widely unknown. Herein, we demonstrate that different L. pneumophila strains induce delayed expression of IL-6 in comparison with IL-8 by human lung epithelial cells. IL-6 expression depended, at early time points, on flagellin recognition by Toll-like receptor (TLR)5, activity of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK)1 and p38 mitogen-activated protein (MAP) kinase, and, at later time points, on the type-IV secretion system. In the same manner, but more rapidly, the recently described transcription factor IκBζ was induced by Legionella infection and, binding to the nuclear factor (NF)-κB subunit p50 - recruited to the il6 promoter together with CCAAT-enhancer-binding protein β and phosphorylated activator protein-1 subunit cJun. Similarly, histone modifications and NF-κB subunit p65/RelA appeared at the iκbζ and subsequently at the il6 gene promoter, thereby initiating gene expression. Gene silencing of IκBζ reduced Legionella-related IL-6 expression by 41%. Overall, these data indicate a sequence of flagellin/TLR5- and type IV-dependent IκBζ expression, recruitment of IκBζ/p50 to the il6 promoter, chromatin remodelling and subsequent IL-6 transcription in L. pneumophila-infected lung epithelial cells.

PKC(alpha) and PKC(epsilon) differentially regulate Legionella pneumophila-induced GM-CSF

Legionella pneumophila is an important causative agent of severe pneumonia in humans. The human alveolar epithelium is an effective barrier for inhaled microorganisms and actively participates in the initiation of innate host defense. Although secretion of granulocyte-macrophage colony-stimulating factor (GM-CSF) is essential for the elimination of invading Legionella spp., mechanisms of Legionella pneumophila-induced release of this cytokine are widely unknown. In this study, we have demonstrated a toll-like receptor (TLR)2- and TLR5-dependent release of GM-CSF in L. pneumophila-infected human alveolar epithelial cells. GM-CSF secretion was not dependent on the bacteria type II or type IV secretion system. Furthermore, an increase in protein kinase C (PKC) activity, particularly PKC(alpha) and PKC(epsilon), was noted. Blocking of PKC(alpha) and PKC(epsilon) activity or expression, but not of PKC(beta), PKC(delta), PKC(eta), PKC(theta), and PKC(zeta), significantly reduced the synthesis of GM-CSF in infected cells. While PKC(alpha) was critical for the initiation of a nuclear factor-kappaB-mediated GM-CSF expression, PKC(epsilon) regulated GM-CSF production via activator protein 1. Thus, differential regulation of GM-CSF, production by PKC isoforms, contributes to the host response in Legionnaires' disease.