Daniel Drömann

The TGF-beta-Pseudoreceptor BAMBI is strongly expressed in COPD lungs and regulated by nontypeable Haemophilus influenzae

BackgroundNontypeable Haemophilus influenzae (NTHI) may play a role as an infectious trigger in the pathogenesis of chronic obstructive pulmonary disease (COPD). Few data are available regarding the influence of acute and persistent infection on tissue remodelling and repair factors such as transforming growth factor (TGF)-β.MethodsNTHI infection in lung tissues obtained from COPD patients and controls was studied in vivo and using an in vitro model. Infection experiments were performed with two different clinical isolates. Detection of NTHI was done using in situ hybridization (ISH) in unstimulated and in in vitro infected lung tissue. For characterization of TGF-β signaling molecules a transcriptome array was performed. Expression of the TGF-pseudoreceptor BMP and Activin Membrane-bound Inhibitor (BAMBI) was analyzed using immunohistochemistry (IHC), ISH and PCR. CXC chemokine ligand (CXCL)-8, tumor necrosis factor (TNF)-α and TGF-β expression were evaluated in lung tissue and cell culture using ELISA.ResultsIn 38% of COPD patients infection with NTHI was detected in vivo in contrast to 0% of controls (p < 0.05). Transcriptome arrays showed no significant changes of TGF-β receptors 1 and 2 and Smad-3 expression, whereas a strong expression of BAMBI with upregulation after in vitro infection of COPD lung tissue was demonstrated. BAMBI was expressed ubiquitously on alveolar macrophages (AM) and to a lesser degree on alveolar epithelial cells (AEC). Measurement of cytokine concentrations in lung tissue supernatants revealed a decreased expression of TGF-β (p < 0.05) in combination with a strong proinflammatory response (p < 0.01).ConclusionsWe show for the first time the expression of the TGF pseudoreceptor BAMBI in the human lung, which is upregulated in response to NTHI infection in COPD lung tissue in vivo and in vitro. The combination of NTHI-mediated induction of proinflammatory cytokines and inhibition of TGF-β expression may influence inflammation induced tissue remodeling.

Streptococcus pneumoniae-induced regulation of cyclooxygenase-2 in human lung tissue

The majority of cases of community-acquired pneumonia are caused by Streptococcus pneumoniae and most studies on pneumococcal host interaction are based on cell culture or animal experiments. Thus, little is known about infections in human lung tissue. Cyclooxygenase-2 and its metabolites play an important regulatory role in lung inflammation. Therefore, we established a pneumococcal infection model on human lung tissue demonstrating mitogen-activated protein kinase (MAPK)-dependent induction of cyclooxygenase-2 and its related metabolites. In addition to alveolar macrophages and the vascular endothelium, cyclooxygenase-2 was upregulated in alveolar type II but not type I epithelial cells, which was confirmed in lungs of patients suffering from acute pneumonia. Moreover, we demonstrated the expression profile of all four E prostanoid receptors at the mRNA level and showed functionality of the E prostanoid4 receptor by cyclic adenosine monophosphate production. Additionally, in comparison to previous studies, cyclooxygenase-2/prostaglandin E2 related pro- and anti-inflammatory mediator regulation was partly confirmed in human lung tissue after pneumococcal infection. Overall, cell type-specific and MAPK-dependent cyclooxygenase-2 expression and prostaglandin E2 formation in human lung tissue may play an important role in the early phase of pneumococcal infections.

Triggering receptor expressed on myeloid cells − 1 (Trem-1) on blood neutrophils is associated with cytokine inducibility in human E . coli sepsis

BackgroundBacterial sepsis induced immunsuppression via antigen hyporesponsibility increases the risk of nosokomial infections and mortality. Pattern recognition receptors (PRR) might have a central role in the pathophysiology of hyporesponsibility.MethodsIn this study we evaluated in a human E. coli sepsis cohort, the role of PRR including TLR’s and Trem-1. Expression of Trem-1, TLR2, TLR4, CD14 and HLA-DR on blood monozytes and neutrophils were examined using flow cytometry from 22 patients with E. coli sepsis and 6 healthy controls. LPS and LTA stimulated TNF alpha, IL-10, IL-8 and IL-6 production was studied in a 24 h whole blood assay. Free cytokine serum concentration of TNF alpha, PCT and IP-10 were evaluated.ResultsWe found a significant higher expression of Trem-1 and TLR-2 on monocytes and neutrophils in patients compared to healthy volunteers. TLR2 expression (p < 0.05) was higher and HLA-DR lower (p < 0.05) on monocytes of patients with severe sepsis compared to patients with simple sepsis. Trem-1 expression was tendentially higher (p = 0,07) on monocytes and lower on neutrophils of patients with severe sepsis. Trem-1 expression on neutrophils was associated with the IL-10 (LPS: r = 0,61, p < 0.02) and TNF-α inducibility (LPS: r = 0,78, p < 0,002). In addition Trem-1 expression on neutrophils shows a negative correlation to the serum levels of TNF alpha (r = −0,63; p < 0,005), IP-10 (r = −0,5; p < 0,035) and procalcitonin (r = −0,59; p < 0,007).ConclusionsPatients with E. coli sepsis are characterized by an association of Trem-1 expression on blood neutrophils with cytokine inducibility. The TREM-1 pathway on neutrophils might play a role in producing an adequate inflammatory and bactericidal response in bacterial sepsis.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/4441869398748313

Innate immunity in the human lung: pathogen recognition and lung disease

As the human lung is exposed to a variety of microbial pathogens in the environment, a first line of defense is built up by pulmonary cells like bronchial/alveolar epithelial cells and alveolar macrophages. These cells express several pattern recognition receptors (PRRs) recognizing highly conserved microbial motifs and initiating the production of chemokines and pro- and anti-inflammatory cytokines acting as transmembrane or intracellular receptors. This might not only lead to acute but also to chronic inflammation which is discussed as an underlying mechanism in the pathogenesis of different lung diseases.

Nontypeable Haemophilus influenzae (NTHi) directly interfere with the regulation of E-cadherin in lung epithelial cells

Loss of epithelial barriers characterized by reduction of E-cadherin is a hallmark of chronic obstructive pulmonary disease (COPD). We investigated the effects of nontypeable Haemophilus influenzae (NTHi) infections, associated with acute exacerbations of chronic bronchitis, on the regulation of E-cadherin in host cells. NTHi infection decreased E-cadherin mRNA and protein-levels in lung epithelial cells. E-cadherin reduction was mediated by activation of the fibroblast growth factor 2 (FGF2), the mammalian target of rapamycin (mTOR) and Slug. These data indicate that epithelial integrity and barrier function is disturbed by NTHi infection. Mainly, the destruction of cell-cell contacts is a prominent feature in NTHi infection.

Budesonide Inhibits Intracellular Infection with Non-Typeable Haemophilus influenzae Despite Its Anti-Inflammatory Effects in Respiratory Cells and Human Lung Tissue: A Role for p38 MAP Kinase.

Background: Inhaled corticosteroids (ICS) are widely used in the treatment of obstructive lung diseases. Recent data suggest a higher pneumonia risk in chronic obstructive pulmonary disease (COPD) patients treated with ICS. Objective: Since non-typeable Haemophilus influenzae (NTHi) is the most common pathogen associated with acute exacerbations of COPD, we investigated the effects of budesonide (BUD) on NTHi-induced inflammation and invasive infection. Methods: The alveolar epithelial cell line A549 and specimens of human lung tissue (HLT) were used in our experiments. Intracellular infection was determined by a lysis/culture assay of infected cells. Activated p38 mitogen-associated protein kinase (MAPK) was assessed using Western blotting and immunohistochemistry, expression of toll-like receptor 2 (TLR2) was determined by PCR, and CXCL-8 levels were measured using ELISA. Immunohistochemistry was used for detection of CXCL-8, platelet-activating factor receptor (PAF-R) and NTHi. Results: BUD significantly reduced CXCL-8 secretion in A549 cells and lung tissue infected with NTHi. Furthermore, BUD decreased the expression of PAF-R in HLT and A549 cells. In A549 cells and HLT, BUD inhibited intracellular infection and - synergistically with NTHi - increased the expression of TLR2 (in A549 cells). TLR2 stimulation did not influence the intracellular infection of A549 cells, but p38 MAPK inhibition resulted in a significant reduction of infection. Conclusion: The present study adds new insights into the effects of glucocorticoids on pulmonary host defence after NTHi infection. Although the inflammatory response to infection is suppressed by BUD, interestingly, the intracellular infection is also inhibited. This effect seems to depend on the inhibition of p38 MAPK - a key enzyme in many pro-inflammatory pathways - as well as of PAF-R expression.

Human alveolar epithelial cells type II are capable of TGFβ-dependent epithelial-mesenchymal-transition and collagen-synthesis

BackgroundThe origin of collagen-producing cells in lung fibrosis is unclear. The involvement of embryonic signaling pathways has been acknowledged and trans-differentiation of epithelial cells is discussed critically. The work presented here investigates the role of TGFB in cytoskeleton remodeling and the expression of Epithelial-Mesenchymal-Transition markers by Alveolar Epithelial Cells Type II and tests the hypothesis if human alveolar epithelial cells are capable of trans-differentiation and production of pro-fibrotic collagen.MethodsPrimary human alveolar epithelial cells type II were extracted from donor tissues and stimulated with TGFβ and a TGFβ-inhibitor. Transcriptome and pathway analyses as well as validation of results on protein level were conducted.ResultsA TGFβ-responsive fingerprint was found and investigated for mutual interactions. Interaction modules exhibited enrichment of genes that favor actin cytoskeleton remodeling, differentiation processes and collagen metabolism. Cross-validation of the TGFβ-responsive fingerprint in an independent IPF dataset revealed overlap of genes and supported the direction of regulated genes and TGFβ-specificity.ConclusionsPrimary human alveolar epithelial cells type II seem undergo a TGFβ-dependent phenotypic change, exhibit differential expression of EMT markers in vitro and acquire the potential to produce collagen.

Die risikoadaptierte Therapie muss sofort beginnen

ZusammenfassungBestätigt sich der Verdacht auf eine Pneumonie, kann man auf das Ergebnis der mikrobiologischen Kultur nicht warten. Bei der empirischen Therapie orientiert sich die Wahl des Antibiotikums nach verschiedenen Kriterien wie etwa der lokalen Resistenzlage sowie Vorbehandlungen und evtl. Grunderkrankungen des Patienten. Unsere Autoren sagen Ihnen, unter welchen Voraussetzungen Sie eine Pneumonie ambulant behandeln können.