Status of HIV and comorbidities in refugees with HIV from Ukraine.

PURPOSE: To describe the clinical characteristics of refugees with HIV from Ukraine that seek continuation of medical care in Germany. METHODS: Fourty-six refugees with HIV that had left Ukraine between 24 February and 30 December 2022 were examined. Information on patients' history was obtained using a standardized questionnaire for clinical care. Interviews were conducted in Russian during their first clinical presentation. RESULTS: Fourty-six persons (41 females and 5 males) were included and their mean age was 39.6 (±8.4) years. The mean time since HIV diagnosis was 8.0 (median, IQR 7.15) years and 70.3% of participants currently received tenfofovir-DF, lamividine and dolutegravir. Most refugees had an undetectable HIV viral load and their current mean CD4 T cell count was 702 (SD ± 289) per µL. Serology revealed previous hepatitis B infection in 50.4% without evidence for replication, with undetectable anti-hepatitis B surface antigen in the remaining refugees. Antibodies against hepatitis C were present in 23 refugees (50%), but only 10 patients had been diagnosed with hepatitis C previously. Five refugees had undergone successful antiviral treatment for hepatitis C. Detectable HCV-RNA was evident in nine patients (19.6%). Sixteen (38.6%) refugees had a positive tuberculosis (TB) interferon gamma release assay, and four were on TB treatment for previously diagnosed infection. One had been diagnosed with multidrug-resistant (MDR) TB, two with pre-extensively drug-resistant (pre-XDR) TB and two with XDR TB and were treated with combinations of second-line and novel agents according to WHO guidelines. CONCLUSIONS: Based on this preliminary analysis of a not fully representative cohort, refugees with HIV from Ukraine were young, mostly healthy females highly adherent to antiretroviral therapy. The rate of transmittable co-infections urges early diagnostic evaluation and treatment.

[SARS-CoV-2-Infection and Interstitial Lung Disease: Position paper of the German Respiratory Society]. / SARS-CoV-2-Infektion und interstitielle Lungenerkrankungen ­ Positionspapier der Deutschen Gesellschaft für Pneumologie und Beatmungsmedizin.

The SARS-CoV-2 pandemic had a tremendous impact on diagnosis and treatment of interstitial lung diseases (ILD). Especially in the early phase of the pandemic, when the delta variant was prevailling, a huge number of viral pneumonias were observed, which worsened pre-existing, triggered de novo occurence or discovery of previously subclincal interstitial lung diseases. The effect of SARS-CoV-2 infection - without or with accompanying viral pneumonia - on the further development of pre-existing ILD as well of new pulmonary inflitrates and consolidiations is difficult to predict and poses a daily challenge to interdisciplinary ILD boards. This position paper of the German Respiratory Society (DGP e.V.) provides answers to the most pressing questions based on current knowledge.

Antibody ligation of CEACAM1, CEACAM3, and CEACAM6, differentially enhance the cytokine release of human neutrophils in responses to Candida albicans.

Invasive candidiasis is a healthcare-associated fungal infection with a high mortality rate. Neutrophils, the first line of defense during fungal infections, express the immunoregulatory Candida albicans receptors CEACAM1, CEACAM3, and CEACAM6. We analyzed the effects of specific antibodies on C. albicans-induced neutrophil responses. CEACAM6 ligation by 1H7-4B and to some extent CEACAM1 ligation by B3-17, but not CEACAM3 ligation by 308/3-3, resulted in the immediate release of stored CXCL8 and altered transcriptional responses of the C. albicans-stimulated neutrophils. Integrated network analyses and dynamic simulations of signaling cascades predicted alterations in apoptosis and cytokine secretion. We verified that CEACAM6 ligation enhanced Candida-induced neutrophil apoptosis and increased long-term IL-1ß/IL-6 release in responses to C. albicans. CEACAM3 ligation, but not CEACAM1 ligation, increased the long-term release of pro-inflammatory IL-1ß/IL-6. Taken together, we demonstrated for the first time that ligation of CEACAM receptors differentially affects the regulation of C. albicans-induced immune functions in human neutrophils.

Recycling and Reshaping-E3 Ligases and DUBs in the Initiation of T Cell Receptor-Mediated Signaling and Response.

T cell activation plays a central role in supporting and shaping the immune response. The induction of a functional adaptive immune response requires the control of signaling processes downstream of the T cell receptor (TCR). In this regard, protein phosphorylation and dephosphorylation have been extensively studied. In the past decades, further checkpoints of activation have been identified. These are E3 ligases catalyzing the transfer of ubiquitin or ubiquitin-like proteins to protein substrates, as well as specific peptidases to counteract this reaction, such as deubiquitinating enzymes (DUBs). These posttranslational modifications can critically influence protein interactions by targeting proteins for degradation by proteasomes or mediating the complex formation required for active TCR signaling. Thus, the basic aspects of T cell development and differentiation are controlled by defining, e.g., the threshold of activation in positive and negative selection in the thymus. Furthermore, an emerging role of ubiquitination in peripheral T cell tolerance has been described. Changes in the function and abundance of certain E3 ligases or DUBs involved in T cell homeostasis are associated with the development of autoimmune diseases. This review summarizes the current knowledge of E3 enzymes and their target proteins regulating T cell signaling processes and discusses new approaches for therapeutic intervention.

Interaction of TLR4 and TLR8 in the Innate Immune Response against Mycobacterium Tuberculosis.

The interaction and crosstalk of Toll-like receptors (TLRs) is an established pathway in which the innate immune system recognises and fights pathogens. In a single nucleotide polymorphisms (SNP) analysis of an Indian cohort, we found evidence for both TLR4-399T and TRL8-1A conveying increased susceptibility towards tuberculosis (TB) in an interdependent manner, even though there is no established TLR4 ligand present in Mycobacterium tuberculosis (Mtb), which is the causative pathogen of TB. Docking studies revealed that TLR4 and TLR8 can build a heterodimer, allowing interaction with TLR8 ligands. The conformational change of TLR4-399T might impair this interaction. With immunoprecipitation and mass spectrometry, we precipitated TLR4 with TLR8-targeted antibodies, indicating heterodimerisation. Confocal microscopy confirmed a high co-localisation frequency of TLR4 and TLR8 that further increased upon TLR8 stimulation. The heterodimerisation of TLR4 and TLR8 led to an induction of IL12p40, NF-κB, and IRF3. TLR4-399T in interaction with TLR8 induced an increased NF-κB response as compared to TLR4-399C, which was potentially caused by an alteration of subsequent immunological pathways involving type I IFNs. In summary, we present evidence that the heterodimerisation of TLR4 and TLR8 at the endosome is involved in Mtb recognition via TLR8 ligands, such as microbial RNA, which induces a Th1 response. These findings may lead to novel targets for therapeutic interventions and vaccine development regarding TB.

A SNP upstream of the cyclic GMP-AMP synthase (cGAS) gene protects from relapse and extra-pulmonary TB and relates to BCG vaccination status in an Indian cohort.

Tuberculosis (TB) caused by Mycobacterium tuberculosis (M.tb) is a major health care threat worldwide causing over a million deaths annually. Host-pathogen interaction is complex, and a strong genetic contribution to disease susceptibility has been proposed. We have investigated single-nucleotide polymorphisms (SNPs) within cGAS/STING in Indian TB patients and healthy cohorts from India and Germany by Lightcycler®480 genotyping technique. The cGAS/STING pathway is an essential defense pathway within the cytosol after M.tb is internalized and mycobacterial DNA is released inducing the production of type I IFNs. We found that the rs311686 SNP upstream of cGAS provides protection from getting TB overall and is differently distributed in pulmonary TB patients compared with extra-pulmonary and particularly relapse cases. This SNP furthermore differs in distribution when comparing individuals with respect to BCG vaccination status. Taken together, our results show that the presence of the rs311686 SNP influences the course of TB significantly. However, structural conformation changes were found only for the cGAS rs610913 SNP. These findings underscore the importance of M.tb DNA recognition for TB pathogenesis and may eventually help in risk stratification of individuals. This may ultimately help in prevention of disease and aid in developing new vaccination and treatment strategies.

Functional surface proteomic profiling reveals the host heat-shock protein A8 as a mediator of Lichtheimia corymbifera recognition by murine alveolar macrophages.

Mucormycosis is an emergent, fatal fungal infection of humans and warm-blooded animals caused by species of the order Mucorales. Immune cells of the innate immune system serve as the first line of defence against inhaled spores. Alveolar macrophages were challenged with the mucoralean fungus Lichtheimia corymbifera and subjected to biotinylation and streptavidin enrichment procedures followed by LC-MS/MS analyses. A total of 28 host proteins enriched for binding to macrophage-L. corymbifera interaction. Among those, the HSP70-family protein Hspa8 was found to be predominantly responsive to living and heat-killed spores of a virulent and an attenuated strain of L. corymbifera. Confocal scanning laser microscopy of infected macrophages revealed colocalization of Hspa8 with phagocytosed spores of L. corymbifera. The amount of detectable Hspa8 was dependent on the multiplicity of infection. Incubation of alveolar macrophages with an anti-Hspa8 antibody prior to infection reduced their capability to phagocytose spores of L. corymbifera. In contrast, anti-Hspa8 antibodies did not abrogate the phagocytosis of Aspergillus fumigatus conidia by macrophages. These results suggest an important contribution of the heat-shock family protein Hspa8 in the recognition of spores of the mucoralean fungus L. corymbifera by host alveolar macrophages and define a potential immunomodulatory therapeutic target.

CEACAM1 inhibits Toll-like receptor 2-triggered antibacterial responses of human pulmonary epithelial cells.

Although Moraxella catarrhalis and Neisseria meningitidis are important human pathogens, they often colonize the human respiratory tract without causing overt clinical symptoms. Both pathogens express structurally unrelated proteins that share the ability to stimulate the adhesion molecule CEACAM1 expressed on human cells. Here we demonstrate that the interaction of CEACAM1 with ubiquitous surface protein A1 expressed on M. catarrhalis or with opacity-associated proteins on N. meningitidis resulted in reduced Toll-like receptor 2-initiated transcription factor NF-kappaB-dependent inflammatory responses of primary pulmonary epithelial cells. These inhibitory effects were mediated by tyrosine phosphorylation of the immunoreceptor tyrosine-based inhibitory motif of CEACAM1 and by recruitment of the phosphatase SHP-1, which negatively regulated Toll-like receptor 2-dependent activation of the phosphatidylinositol 3-OH kinase-Akt kinase pathway. Our results identify a CEACAM1-dependent immune-evasion strategy.

Controlling intestinal colonization of high-risk haematology patients with ESBL-producing Enterobacteriaceae: a randomized, placebo-controlled, multicentre, Phase II trial (CLEAR).

OBJECTIVES: We assessed the efficacy and safety of an oral antimicrobial regimen for short- and long-term intestinal eradication of ESBL-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EC/KP) in immunocompromised patients. METHODS: We performed a randomized (2:1), double-blind multicentre Phase II study in four haematology-oncology departments. Patients colonized with ESBL-EC/KP received a 7 day antimicrobial regimen of oral colistin (2 × 106 IU 4×/day), gentamicin (80 mg 4×/day) and fosfomycin (three administrations of 3 g every 72 h), or placebo. Faecal, throat and urine specimens were collected on day 0, 6 ± 2, 11 ± 2, 28 ± 4 and 42 ± 4 after treatment initiation, and the quantitative burden of ESBL-EC/KP, resistance genes and changes in intestinal microbiota were analysed. Clinicaltrials.gov: NCT01931592. RESULTS: As the manufacture of colistin powder was suspended worldwide, the study was terminated prematurely. Overall, 29 (18 verum/11 placebo) out of 47 patients were enrolled. The short-term intestinal eradication was marginal at day 6 (verum group 15/18, 83.3% versus placebo 2/11, 18.2%; relative risk 4.58, 95% CI 1.29-16.33; Fisher's exact test P = 0.001) and not evident at later timepoints. Quantitative analysis showed a significant decrease of intestinal ESBL-EC/KP burden on day 6. Sustained intestinal eradication (day 28 + 42) was not achieved (verum, 38.9% versus placebo, 27.3%; P = 0.299). In the verum group, mcr-1 genes were detected in two faecal samples collected after treatment. Microbiome analysis showed a significant decrease in alpha diversity and a shift in beta diversity. CONCLUSIONS: In this prematurely terminated study of a 7 day oral antimicrobial eradication regimen, short-term ESBL-EC/KP suppression was marginal, while an altered intestinal microbiota composition was clearly apparent.

The composition of the pulmonary microbiota in sarcoidosis - an observational study.

BACKGROUND: Sarcoidosis is a systemic disease of unknown etiology. The disease mechanisms are largely speculative and may include the role microbial patterns that initiate and drive an underlying immune process. The aim of this study was to characterize the microbiota of the lung of patients with sarcoidosis and compare its composition and diversity with the results from patients with other interstitial lung disease (ILD) and historic healthy controls. METHODS: Patients (sarcoidosis, n = 31; interstitial lung disease, n = 19) were recruited within the PULMOHOM study, a prospective cohort study to characterize inflammatory processes in pulmonary diseases. Bronchoscopy of the middle lobe or the lingula was performed and the recovered fluid was immediately sent for analysis of the pulmonary microbiota by 16sRNA gene sequencing. Subsequent bioinformatic analysis was performed to compare the groups. RESULTS: There were no significant differences between patients with sarcoidosis or other ILDs with regard to microbiome composition and diversity. In addition, the abundance of the genera Atopobium, Fusobacterium, Mycobacterium or Propionibacterium were not different between the two groups. There were no gross differences to historical healthy controls. CONCLUSION: The analysis of the pulmonary microbiota based on 16sRNA gene sequencing did not show a significant dysbiosis in patients with sarcoidosis as compared to other ILD patients. These data do not exclude a microbiological component in the pathogenesis of sarcoidosis.

Digital Image Analyses on Whole-Lung Slides in Mouse Models of Acute Pneumonia.

Descriptive histopathology of mouse models of pneumonia is essential in assessing the outcome of infections, molecular manipulations, or therapies in the context of whole lungs. Quantitative comparisons between experimental groups, however, have been limited to laborious stereology or ill-defined scoring systems that depend on the subjectivity of a more or less experienced observer. Here, we introduce self-learning digital image analyses that allow us to transform optical information from whole mouse lung sections into statistically testable data. A pattern-recognition-based software and a nuclear count algorithm were adopted to quantify user-defined pathologies from whole slide scans of lungs infected with Streptococcus pneumoniae or influenza A virus compared with PBS-challenged lungs. The readout parameters "relative area affected" and "nuclear counts per area" are proposed as relevant criteria for the quantification of lesions from hematoxylin and eosin-stained sections, also allowing for the generation of a heat map of, for example, immune cell infiltrates with anatomical assignments across entire lung sections. Moreover, when combined with immunohistochemical labeling of marker proteins, both approaches are useful for the identification and counting of, for example, immune cell populations, as validated here by direct comparisons with flow cytometry data. The solutions can easily and flexibly be adjusted to specificities of different models or pathogens. Automated digital analyses of whole mouse lung sections may set a new standard for the user-defined, high-throughput comparative quantification of histological and immunohistochemical images. Still, our algorithms established here are only a start, and need to be tested in additional studies and other applications in the future.

The sirtuin 1/2 inhibitor tenovin-1 induces a nonlinear apoptosis-inducing factor-dependent cell death in a p53 null Ewing's sarcoma cell line.

The sirtuin 1/2 inhibitor tenovin-1 activates p53 and may have potential in the management of cancer. Here, we investigated the responsiveness of Ewing's sarcoma cells to tenovin-1. We examined its effects in two Ewing's sarcoma cell lines with different p53 status, i.e. in p53 wild-type and p53 null cells. Effects were assessed by flow cytometric analyses of cell death, mitochondrial membrane depolarization and reactive oxygen species (ROS) generation, by caspase 3/7 activity measurement, by mRNA expression profiling and by immunoblotting. Tenovin-1 elicited caspase-mediated cell death in p53 wild-type cells, but caspase-independent cell death in p53 null cells. Remarkably, it induced a nonlinear concentration response in the latter: low concentrations of tenovin-1 were much more effective than were higher concentrations. Tenovin-1's effects in p53 null cells involved gene expression changes of Bcl-2 family members, mitochondrial membrane depolarization, nuclear translocation of apoptosis-inducing factor, ROS formation and DNA damage; all these effects followed a bell-shaped pattern. In conclusion, our results provide new insights into tenovin-1's mode of action by demonstrating that it can induce different pathways of cell death.

Fungal biomarker discovery by integration of classifiers.

BACKGROUND: The human immune system is responsible for protecting the host from infection. However, in immunocompromised individuals the risk of infection increases substantially with possible drastic consequences. In extreme, systemic infection can lead to sepsis which is responsible for innumerous deaths worldwide. Amongst its causes are infections by bacteria and fungi. To increase survival, it is mandatory to identify the type of infection rapidly. Discriminating between fungal and bacterial pathogens is key to determine if antifungals or antibiotics should be administered, respectively. For this, in situ experiments have been performed to determine regulation mechanisms of the human immune system to identify biomarkers. However, these studies led to heterogeneous results either due different laboratory settings, pathogen strains, cell types and tissues, as well as the time of sample extraction, to name a few. METHODS: To generate a gene signature capable of discriminating between fungal and bacterial infected samples, we employed Mixed Integer Linear Programming (MILP) based classifiers on several datasets comprised of the above mentioned pathogens. RESULTS: When combining the classifiers by a joint optimization we could increase the consistency of the biomarker gene list independently of the experimental setup. An increase in pairwise overlap (the number of genes that overlap in each cross-validation) of 43% was obtained by this approach when compared to that of single classifiers. The refined gene list was composed of 19 genes and ranked according to consistency in expression (up- or down-regulated) and most of them were linked either directly or indirectly to the ERK-MAPK signalling pathway, which has been shown to play a key role in the immune response to infection. Testing of the identified 12 genes on an unseen dataset yielded an average accuracy of 83%. CONCLUSIONS: In conclusion, our method allowed the combination of independent classifiers and increased consistency and reliability of the generated gene signatures.

Moraxella catarrhalis decreases antiviral innate immune responses by down-regulation of TLR3 via inhibition of p53 in human bronchial epithelial cells.

Chronic obstructive pulmonary disease (COPD) is complicated by infectious exacerbations with acute worsening of respiratory symptoms. Coinfections of bacterial and viral pathogens are associated with more severe exacerbations. Moraxella catarrhalis is one of the most frequent lower respiratory tract pathogens detected in COPD. We therefore studied the impact of M. catarrhalis on the antiviral innate immune response that is mediated via TLR3 and p53. Molecular interactions between M. catarrhalis and normal human bronchial epithelial (NHBE) cells as well as Beas-2B cells were studied using flow cytometry, quantitative PCR analysis, chromatin immunoprecipitation, RNA interference, and ELISA. M. catarrhalis induces a significant down-regulation of TLR3 in human bronchial epithelial cells. In M. catarrhalis-infected cells, expression of p53 was decreased. We detected a reduced binding of p53 to the tlr3 promoter, resulting in reduced TLR3 gene transcription. M. catarrhalis diminished the TLR3-dependent secretion of IFN-ß, IFN-λ, and chemokine (C-X-C motif) ligand 8. In addition in M. catarrhalis infected cells, expression of rhinovirus type 1A RNA was increased compared with uninfected cells. M. catarrhalis reduces antiviral defense functions of bronchial epithelial cells, which may increase susceptibility to viral infections.-Heinrich, A., Haarmann, H., Zahradnik, S., Frenzel, K., Schreiber, F., Klassert, T. E., Heyl, K. A., Endres, A.-S., Schmidtke, M., Hofmann, J., Slevogt, H. Moraxella catarrhalis decreases antiviral innate immune responses by down-regulation of TLR3 via inhibition of p53 in human bronchial epithelial cells.

Galectin-3 binds highly galactosylated IgG1 and is crucial for the IgG1 complex mediated inhibition of C5aReceptor induced immune responses.

Changes in the glycosylation of immunoglobulins have been shown to modulate immune homeostasis and disease pathology. In this sense it has been shown that highly galactosylated but not agalactosylated IgG1 immune complexes (ICs) inhibit C5aR-mediated pro-inflammatory immune responses via the assembly of FcγRIIB-Dectin-1 receptor complexes. In this study we demonstrated that Galectin-3, a galactose-binding lectin that is known to cross-link proteins on cell-surfaces via binding their N-glycans, bound to highly-galactosylated, but not agalactosylated IgG1. Further, Galectin-3 was essential for the IC-mediated inhibition of C5a-induced neutrophil chemotaxis in vitro. Taken together our results indicate that Galectin-3 mediates the interaction of ICs with the FcγRIIB-Dectin-1 receptor complex for delivering immunoregulatory signals to inhibit C5aR-mediated immune responses.

C-type lectin receptors in tuberculosis: what we know.

Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis (TB), is recognized by a number of pathogen recognition receptors (PRRs), either soluble or predominantly expressed on the surface of various cells of innate and adaptive immunity. C-type lectin receptors (CTLRs) are a class of PRRs which can recognize a variety of endogenous and exogenous ligands, thereby playing a crucial role in immunity, as well as in maintaining homeostasis. Mtb surface ligands, including mannose-capped lipoarabinomannan and cord factor, are important immune modulators which recently have been found to be directly recognized by several CTLRs. Receptor ligation is followed by cellular activation, mainly via nuclear factor κB mediated by a series of adaptors with subsequent expression of pro-inflammatory cytokines. Mtb recognition by CTLRs and their cross talk with other PRRs on immune cells is of key importance for the better understanding of the Mtb-induced complexity of the host immune responses. Epidemiological studies have shown that single nucleotide polymorphisms (SNPs) in several PRRs, as well as the adaptors in their signaling cascades, are directly involved in the susceptibility for developing disease and the disease outcome. In addition, an increasing number of CTLRs have been studied for their functional effects in the pathogenesis of TB. This review summarizes current knowledge regarding the various roles played by different CTLRs in TB, as well as the role of their SNPs associated with disease susceptibility and outcome in different human populations.

Burden and spectrum of infectious disease in Germany 2009-2014: a multicentre study from Berlin's Municipal Hospitals.

PURPOSE: This study aimed at assessing the burden and spectrum of infectious diseases (ID) in a Metropolitan population in Germany. METHODS: A discharge database using ICD-10 codes enabled the identification of hospitalizations with infection-related diagnoses. All hospital admissions between 2009 and 2014 were analysed from 9 municipal hospitals serving approximately one-third of an urban population of 3.5 million people. RESULTS: We identified 114,168 admissions with a primary (first-listed) ID diagnosis and 220,483 admissions with any-listed ID diagnosis, accounting for 8.9 % [95 % confidence interval (CI) 8.9-9.0 %] and 17.2 % (95 % CI 17.1-17.3) of all 1,284,559 admissions, respectively. Annually, 439,837 bed-days (range 413,707-488,520) were occupied by patients with an ID diagnosis, utilizing 22.8 % of total bed capacity. The median length of stay for patients with primary ID diagnosis and secondary ID diagnosis was 6 days (IQR 3-11) and 10 days (IQR 5-19), respectively. The most common diagnosis across all age groups was "pneumonia" (22.8 and 16.2 % of ID admissions as primary and secondary diagnosis, respectively). In-hospital mortality was 6.8 % (95 % CI 6.6-6.9) and 8.9 % (95 % CI 8.7-9.1) for ID as primary and secondary diagnosis, respectively. CONCLUSION: Infectious diseases contribute significantly to the overall burden of disease in a health system caring for an urban German population. In view of the magnitude of ID's contribution, establishing more specialists in ID medicine and adjusting the reimbursements for managing infection-related admissions should be made a public health priority in Germany.

Moraxella catarrhalis induces an immune response in the murine lung that is independent of human CEACAM5 expression and long-term smoke exposure.

In patients with chronic obstructive pulmonary disease (COPD), Moraxella catarrhalis infection of the lower airways is associated with chronic colonization and inflammation during stable disease and acute exacerbations. Chronic smoke exposure induces chronic inflammation and impairs mucociliary clearance, thus contributing to bacterial colonization of the lower airways in COPD patients. The human-specific carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 5, expressed in human airways, has been shown to contribute to epithelial colonization of CEACAM-binding pathogens. To investigate the impact of CEACAM5 expression on pulmonary M. catarrhalis colonization, we infected mice transgenic for human CEACAM5 (hCEACAM5) and wild type mice intratracheally with M. catarrhalis with or without preceding smoke exposure and analyzed bacterial colonization and local and systemic inflammation. Our results show that airway infection with M. catarrhalis accelerated acute local but not systemic inflammation, albeit independent of hCEACAM5 expression. Long-term smoke exposure alone or prior to M. catarrhalis infection did not contribute to increased local or systemic inflammation. No difference was found in pulmonary clearance of M. catarrhalis in hCEACAM5-transgenic mice compared with wild-type mice. Smoke exposure neither altered time nor extent of persistence of M. catarrhalis in the lungs of both genotypes. In conclusion, M. catarrhalis induced a local acute immune response in murine airways. Neither hCEACAM5 expression nor chronic smoke exposure nor a combination of both was sufficient as prerequisites for the establishment of chronic M. catarrhalis colonization. Our results demonstrate the difficulties in mirroring conditions of chronic airways colonization of M. catarrhalis in a murine model.

The role and regulation of Moraxella catarrhalis-induced human beta-defensin 3 expression in human pulmonary epithelial cells.

BACKGROUND: Bacterial colonisation with Moraxella catarrhalis may partly sustain chronic inflammation in the lower airways of patients with chronic obstructive pulmonary disease (COPD). In addition, this bacterium causes infectious exacerbations of COPD, which often necessitate treatment with antibiotics. Antimicrobial peptides are the body's own antibiotic substances with bactericidal and bacteriostatic, as well as immunomodulatory function. In particular, human beta-defensin 3 (hBD-3) exerts an antimicrobial effect against an extraordinarily broad spectrum of pathogens. We therefore investigated the role of hBD-3 in infections of pulmonary epithelial cells with M. catarrhalis. METHODS: The antimicrobial activity of hBD-3 vs. M. catarrhalis was evaluated in an antimicrobial susceptibility assay. We analyzed hBD-3 secretion of M. catarrhalis-infected pulmonary epithelial cells using ELISA. The role of M. catarrhalis-specific virulence factors, toll-like receptors (TLR) 2 and 4, MAPK pathways, and transcription factors AP-1 and NF-κB in the induction and regulation of hBD-3 expression were explored with specific inhibitors, small interference RNA, Western Blot, and chromatin immunoprecipitation (ChIP) assays. RESULTS: HBD-3 exhibited a strong bactericidal effect against M. catarrhalis. M. catarrhalis induced hBD-3 expression in pulmonary epithelial cells, which was dependent on M. catarrhalis membranous lipoolygosaccharide (LOS), while the surface proteins UspA1 and UspA2 were not involved. Gene silencing of TLR2, but not TLR4, led to a reduced hBD-3 secretion after stimulation with M. catarrhalis or M. catarrhalis LOS. Inhibition of MAPKs ERK1/2 and JNK, but not p38, reduced hBD-3 secretion. HBD-3 expression was mediated through the recruitment of AP-1 to the hBD-3 gene promoter and was independent of NF-κB. CONCLUSION: The immune response of pulmonary epithelial cells towards M. catarrhalis involves secretion of hBD-3, which has a bactericidal effect against this pathogen. Binding of M. catarrhalis virulence factor LOS to TLR2 causes an ERK1/2- and JNK-dependent induction of AP-1-related transcription of the hBD-3 gene, resulting in the production and secretion of hBD-3.

The Moraxella catarrhalis-induced pro-inflammatory immune response is enhanced by the activation of the epidermal growth factor receptor in human pulmonary epithelial cells.

BACKGROUND: Chronic lower airway inflammation is considered to be a major cause of pathogenesis and disease progression in chronic obstructive pulmonary disease (COPD). Moraxella catarrhalis is a COPD-associated pathogen causing exacerbations and bacterial colonization in the lower airways of patients, which may contribute to chronic inflammation. Increasing evidence suggests that the epidermal growth factor receptor (EGFR) modulates inflammatory processes in the human airways. The goal of this study was to investigate the role of EGFR in the M. catarrhalis-induced pro-inflammatory immune response in airway epithelial cells. METHODS: The effects of inhibition and gene silencing of EGFR on M. catarrhalis-dependent pro-inflammatory cytokine expression in human primary bronchial epithelial cells (NHBEs), as well as the pulmonary epithelial cell lines BEAS-2B and A549 were analyzed. We also assessed the involvement of EGFR-dependent ERK and NF-κB signaling pathways. RESULTS: The M. catarrhalis-induced pro-inflammatory immune response depends, at least in part, on the phosphorylation and activation of the EGF receptor. Interaction of M. catarrhalis with EGFR increases the secretion of pro-inflammatory cytokines, which is mediated via ERK and NF-κB activation. CONCLUSION: The interaction between M. catarrhalis and EGFR increases airway inflammation caused by this pathogen. Our data suggest that the inhibition of EGFR signaling in COPD could be an interesting target for reducing M. catarrhalis-induced airway inflammation.