Publications by authors named "Stefan Hippenstiel"

111 Publications

Induction of Krüppel-Like Factor 4 Mediates Polymorphonuclear Neutrophil Activation in Infection.

Front Microbiol 2020 3;11:582070. Epub 2021 Feb 3.

Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.

The recruitment and activation of polymorphonuclear neutrophils (PMNs) are of central importance for the elimination of pathogens in bacterial infections. We investigated the -dependent induction of the transcription factor Krüppel-like factor (KLF) 4 in PMNs as a potential regulator of PMN activation. We found that KLF4 expression is induced in human blood-derived PMNs in a time- and dose-dependent manner by wild-type and capsule knockout mutants. Unencapsulated knockout mutants induced stronger KLF4 expression than encapsulated wild types. The presence of autolysin LytA-competent (thus viable) pneumococci and LytA-mediated bacterial autolysis were required for KLF4 induction in human and murine PMNs. LyzMcre-mediated knockdown of KLF4 in murine blood-derived PMNs revealed that KLF4 influences pneumococci killing and increases the release of the proinflammatory cytokines tumor necrosis factor α and keratinocyte chemoattractant and decreases the release of the anti-inflammatory cytokine interleukin-10. Thus, induces KLF4 expression in PMNs, which contributes to PMN activation in infection.
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http://dx.doi.org/10.3389/fmicb.2020.582070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7887292PMC
February 2021

Transcriptional analysis identifies potential biomarkers and molecular regulators in acute malaria infection.

Life Sci 2021 Apr 2;270:119158. Epub 2021 Feb 2.

Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-Universität Marburg, Marburg, Germany; Department of Internal Medicine, Pulmonary and Critical Care Medicine, University Medical Center Giessen and Marburg, Philipps-Universität Marburg, German Center for Lung Research (DZL), Marburg, Germany; German Center for Lung Research (DZL), German Center for infectious Disease Research (DZIF), Center for Synthetic Microbiology (Synmikro), Philipps-Universität Marburg, Germany. Electronic address:

Aims: Malaria is a serious health threat in tropical countries. The causative parasite of Malaria tropica, the severe form, is the protozoan Plasmodium falciparum. In humans, it infects red blood cells, compromising blood flow and tissue perfusion. This study aims to identify potential biomarkers and RNA networks in leukocyte transcriptomes from patients suffering from Malaria tropica.

Materials And Methods: We identified differentially regulated mRNAs and microRNAs in peripheral blood leukocytes of healthy donors and Malaria patients. Genes whose expression changes were not attributable to changes in leukocyte composition were used for bioinformatics analysis and network construction. Using a previously published cohort of community-acquired pneumonia (CAP) patients, we established discriminating transcriptomic features versus Malaria. We aimed to establish differences between the patient groups by principal component (PCA) and receiving operator characteristic (ROC) analyses and in silico cell type deconvolution.

Key Findings: We found 870 genes that were significantly differentially expressed between healthy donors and Malaria patients. E2F1, BIRC5 and CCNB1 were identified to be primarily responsible for PCA separation of these two groups. We searched for biological function and found that cell cycle processes were strongly activated. By in silico cell type deconvolution, we attribute this to an expansion of γδ T cells. Additional discrimination between CAP and Malaria yielded 445 differentially expressed genes, among which immune proteasome transcripts PSMB8, PSMB9 and PSMB10 were significantly induced in Malaria.

Significance: We identified transcripts from patient leukocytes that differentiate between healthy, Malaria and CAP, and indicate a biological context with potential pathophysiological relevance.
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http://dx.doi.org/10.1016/j.lfs.2021.119158DOI Listing
April 2021

A Therapeutic Non-self-reactive SARS-CoV-2 Antibody Protects from Lung Pathology in a COVID-19 Hamster Model.

Cell 2020 11 23;183(4):1058-1069.e19. Epub 2020 Sep 23.

German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117 Berlin, Germany; Helmholtz Innovation Lab BaoBab (Brain Antibody-omics and B-cell Lab), 10117 Berlin, Germany; Department of Neurology and Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, 10117 Berlin, Germany. Electronic address:

The emergence of SARS-CoV-2 led to pandemic spread of coronavirus disease 2019 (COVID-19), manifesting with respiratory symptoms and multi-organ dysfunction. Detailed characterization of virus-neutralizing antibodies and target epitopes is needed to understand COVID-19 pathophysiology and guide immunization strategies. Among 598 human monoclonal antibodies (mAbs) from 10 COVID-19 patients, we identified 40 strongly neutralizing mAbs. The most potent mAb, CV07-209, neutralized authentic SARS-CoV-2 with an IC value of 3.1 ng/mL. Crystal structures of two mAbs in complex with the SARS-CoV-2 receptor-binding domain at 2.55 and 2.70 Å revealed a direct block of ACE2 attachment. Interestingly, some of the near-germline SARS-CoV-2-neutralizing mAbs reacted with mammalian self-antigens. Prophylactic and therapeutic application of CV07-209 protected hamsters from SARS-CoV-2 infection, weight loss, and lung pathology. Our results show that non-self-reactive virus-neutralizing mAbs elicited during SARS-CoV-2 infection are a promising therapeutic strategy.
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http://dx.doi.org/10.1016/j.cell.2020.09.049DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7510528PMC
November 2020

Reversion of pneumolysin induced executioner caspase activation redirects cells to survival.

J Infect Dis 2020 Oct 12. Epub 2020 Oct 12.

Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charitéplatz, Berlin, Germany.

Apoptosis is an indispensable mechanism for eliminating infected cells and activation of executioner caspases is considered as a point of no return. Streptococcus pneumoniae, the most common bacterial pathogen causing community-acquired pneumonia, induces apoptosis via its pore forming toxin pneumolysin, leading to rapid influxes of mitochondrial calcium [Ca 2+]m as well as fragmentation, loss of motility and membrane potential, which is accompanied by caspase-3/7 activation. Using machine-learning and quantitative live-cell microscopy, we identified a significant number of alveolar epithelial cells surviving such executioner caspase activation after pneumolysin attack. Precise single cell analysis revealed the [Ca 2+]m amplitude and efflux rate as decisive parameters for survival and death, which was verified by pharmacological inhibition of [Ca 2+]m efflux shifting the surviving cells towards the dying fraction. Taken together, we identified the regulation of [Ca 2+]m as critical for controlling the cellular fate under pneumolysin attack, which might be useful for therapeutic intervention during pneumococcal infection.
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http://dx.doi.org/10.1093/infdis/jiaa639DOI Listing
October 2020

A SARS-CoV-2 neutralizing antibody protects from lung pathology in a COVID-19 hamster model.

bioRxiv 2020 Aug 16. Epub 2020 Aug 16.

German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany.

The emergence of SARS-CoV-2 led to pandemic spread of coronavirus disease 2019 (COVID-19), manifesting with respiratory symptoms and multi-organ dysfunction. Detailed characterization of virus-neutralizing antibodies and target epitopes is needed to understand COVID-19 pathophysiology and guide immunization strategies. Among 598 human monoclonal antibodies (mAbs) from ten COVID-19 patients, we identified 40 strongly neutralizing mAbs. The most potent mAb CV07-209 neutralized authentic SARS-CoV-2 with IC50 of 3.1 ng/ml. Crystal structures of two mAbs in complex with the SARS-CoV-2 receptor-binding domain at 2.55 and 2.70 A revealed a direct block of ACE2 attachment. Interestingly, some of the near-germline SARS-CoV-2 neutralizing mAbs reacted with mammalian self-antigens. Prophylactic and therapeutic application of CV07-209 protected hamsters from SARS-CoV-2 infection, weight loss and lung pathology. Our results show that non-self-reactive virus-neutralizing mAbs elicited during SARS-CoV-2 infection are a promising therapeutic strategy.
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http://dx.doi.org/10.1101/2020.08.15.252320DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7430590PMC
August 2020

Severe COVID-19 Is Marked by a Dysregulated Myeloid Cell Compartment.

Cell 2020 09 5;182(6):1419-1440.e23. Epub 2020 Aug 5.

Department of Infectious Diseases and Respiratory Medicine, Charité, Universitätsmedizin Berlin, Berlin, Germany; German Center for Lung Research (DZL).

Coronavirus disease 2019 (COVID-19) is a mild to moderate respiratory tract infection, however, a subset of patients progress to severe disease and respiratory failure. The mechanism of protective immunity in mild forms and the pathogenesis of severe COVID-19 associated with increased neutrophil counts and dysregulated immune responses remain unclear. In a dual-center, two-cohort study, we combined single-cell RNA-sequencing and single-cell proteomics of whole-blood and peripheral-blood mononuclear cells to determine changes in immune cell composition and activation in mild versus severe COVID-19 (242 samples from 109 individuals) over time. HLA-DRCD11c inflammatory monocytes with an interferon-stimulated gene signature were elevated in mild COVID-19. Severe COVID-19 was marked by occurrence of neutrophil precursors, as evidence of emergency myelopoiesis, dysfunctional mature neutrophils, and HLA-DR monocytes. Our study provides detailed insights into the systemic immune response to SARS-CoV-2 infection and reveals profound alterations in the myeloid cell compartment associated with severe COVID-19.
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http://dx.doi.org/10.1016/j.cell.2020.08.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7405822PMC
September 2020

SARS-CoV-2-reactive T cells in healthy donors and patients with COVID-19.

Nature 2020 11 29;587(7833):270-274. Epub 2020 Jul 29.

Si-M/'Der Simulierte Mensch', Technische Universität Berlin and Charité-Universitätsmedizin Berlin, Berlin, Germany.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the rapidly unfolding coronavirus disease 2019 (COVID-19) pandemic. Clinical manifestations of COVID-19 vary, ranging from asymptomatic infection to respiratory failure. The mechanisms that determine such variable outcomes remain unresolved. Here we investigated CD4 T cells that are reactive against the spike glycoprotein of SARS-CoV-2 in the peripheral blood of patients with COVID-19 and SARS-CoV-2-unexposed healthy donors. We detected spike-reactive CD4 T cells not only in 83% of patients with COVID-19 but also in 35% of healthy donors. Spike-reactive CD4 T cells in healthy donors were primarily active against C-terminal epitopes in the spike protein, which show a higher homology to spike glycoproteins of human endemic coronaviruses, compared with N-terminal epitopes. Spike-protein-reactive T cell lines generated from SARS-CoV-2-naive healthy donors responded similarly to the C-terminal region of the spike proteins of the human endemic coronaviruses 229E and OC43, as well as that of SARS-CoV-2. This results indicate that spike-protein cross-reactive T cells are present, which were probably generated during previous encounters with endemic coronaviruses. The effect of pre-existing SARS-CoV-2 cross-reactive T cells on clinical outcomes remains to be determined in larger cohorts. However, the presence of spike-protein cross-reactive T cells in a considerable fraction of the general population may affect the dynamics of the current pandemic, and has important implications for the design and analysis of upcoming trials investigating COVID-19 vaccines.
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http://dx.doi.org/10.1038/s41586-020-2598-9DOI Listing
November 2020

Ultra-High-Throughput Clinical Proteomics Reveals Classifiers of COVID-19 Infection.

Cell Syst 2020 07 2;11(1):11-24.e4. Epub 2020 Jun 2.

The Francis Crick Institute, Molecular Biology of Metabolism Laboratory, London NW11AT, UK; Charité Universitätsmedizin, Department of Biochemistry, 10117 Berlin, Germany. Electronic address:

The COVID-19 pandemic is an unprecedented global challenge, and point-of-care diagnostic classifiers are urgently required. Here, we present a platform for ultra-high-throughput serum and plasma proteomics that builds on ISO13485 standardization to facilitate simple implementation in regulated clinical laboratories. Our low-cost workflow handles up to 180 samples per day, enables high precision quantification, and reduces batch effects for large-scale and longitudinal studies. We use our platform on samples collected from a cohort of early hospitalized cases of the SARS-CoV-2 pandemic and identify 27 potential biomarkers that are differentially expressed depending on the WHO severity grade of COVID-19. They include complement factors, the coagulation system, inflammation modulators, and pro-inflammatory factors upstream and downstream of interleukin 6. All protocols and software for implementing our approach are freely available. In total, this work supports the development of routine proteomic assays to aid clinical decision making and generate hypotheses about potential COVID-19 therapeutic targets.
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http://dx.doi.org/10.1016/j.cels.2020.05.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264033PMC
July 2020

Studying the pathophysiology of coronavirus disease 2019: a protocol for the Berlin prospective COVID-19 patient cohort (Pa-COVID-19).

Infection 2020 Aug 13;48(4):619-626. Epub 2020 Jun 13.

Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health, Campus Virchow Klinikum, Augustenburgerplatz 1, 13353, Berlin, Germany.

Purpose: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide causing a global health emergency. Pa-COVID-19 aims to provide comprehensive data on clinical course, pathophysiology, immunology and outcome of COVID-19, to identify prognostic biomarkers, clinical scores, and therapeutic targets for improved clinical management and preventive interventions.

Methods: Pa-COVID-19 is a prospective observational cohort study of patients with confirmed SARS-CoV-2 infection treated at Charité - Universitätsmedizin Berlin. We collect data on epidemiology, demography, medical history, symptoms, clinical course, and pathogen testing and treatment. Systematic, serial blood sampling will allow deep molecular and immunological phenotyping, transcriptomic profiling, and comprehensive biobanking. Longitudinal data and sample collection during hospitalization will be supplemented by long-term follow-up.

Results: Outcome measures include the WHO clinical ordinal scale on day 15 and clinical, functional, and health-related quality-of-life assessments at discharge and during follow-up. We developed a scalable dataset to (i) suit national standards of care, (ii) facilitate comprehensive data collection in medical care facilities with varying resources, and (iii) allow for rapid implementation of interventional trials based on the standardized study design and data collection. We propose this scalable protocol as blueprint for harmonized data collection and deep phenotyping in COVID-19 in Germany.

Conclusion: We established a basic platform for harmonized, scalable data collection, pathophysiological analysis, and deep phenotyping of COVID-19, which enables rapid generation of evidence for improved medical care and identification of candidate therapeutic and preventive strategies. The electronic database accredited for interventional trials allows fast trial implementation for candidate therapeutic agents.

Trial Registration: Registered at the German registry for clinical studies (DRKS00021688).
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http://dx.doi.org/10.1007/s15010-020-01464-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293426PMC
August 2020

Phage capsid nanoparticles with defined ligand arrangement block influenza virus entry.

Nat Nanotechnol 2020 05 30;15(5):373-379. Epub 2020 Mar 30.

Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.

Multivalent interactions at biological interfaces occur frequently in nature and mediate recognition and interactions in essential physiological processes such as cell-to-cell adhesion. Multivalency is also a key principle that allows tight binding between pathogens and host cells during the initial stages of infection. One promising approach to prevent infection is the design of synthetic or semisynthetic multivalent binders that interfere with pathogen adhesion. Here, we present a multivalent binder that is based on a spatially defined arrangement of ligands for the viral spike protein haemagglutinin of the influenza A virus. Complementary experimental and theoretical approaches demonstrate that bacteriophage capsids, which carry host cell haemagglutinin ligands in an arrangement matching the geometry of binding sites of the spike protein, can bind to viruses in a defined multivalent mode. These capsids cover the entire virus envelope, thus preventing its binding to the host cell as visualized by cryo-electron tomography. As a consequence, virus infection can be inhibited in vitro, ex vivo and in vivo. Such highly functionalized capsids present an alternative to strategies that target virus entry by spike-inhibiting antibodies and peptides or that address late steps of the viral replication cycle.
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http://dx.doi.org/10.1038/s41565-020-0660-2DOI Listing
May 2020

Adult Tissue Extracellular Matrix Determines Tissue Specification of Human iPSC-Derived Embryonic Stage Mesodermal Precursor Cells.

Adv Sci (Weinh) 2020 Mar 21;7(5):1901198. Epub 2020 Jan 21.

Berlin Institute of Health Center for Regenerative Therapies Charité Universitätsmedizin Berlin Augustenburger Platz 1 13353 Berlin Germany.

The selection of pluripotent stem cell (PSC)-derived cells for tissue modeling and cell therapy will be influenced by their response to the tissue environment, including the extracellular matrix (ECM). Whether and how instructive memory is imprinted in adult ECM and able to impact on the tissue specific determination of human PSC-derived developmentally fetal mesodermal precursor (P-meso) cells is investigated. Decellularized ECM (dECM) is generated from human heart, kidney, and lung tissues and recellularized with P-meso cells in a medium not containing any differentiation inducing components. While P-meso cells on kidney dECM differentiate exclusively into nephronal cells, only beating clusters containing mature and immature cardiac cells form on heart dECM. No tissue-specific differentiation of P-meso cells is observed on endoderm-derived lung dECM. P-meso-derived endothelial cells, however, are found on all dECM preparations independent of tissue origin. Clearance of heparan-sulfate proteoglycans (HSPG) from dECM abolishes induction of tissue-specific differentiation. It is concluded that HSPG-bound factors on adult tissue-derived ECM are essential and sufficient to induce tissue-specific specification of uncommitted fetal stage precursor cells.
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http://dx.doi.org/10.1002/advs.201901198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7055561PMC
March 2020

Transcriptional analysis identifies potential biomarkers and molecular regulators in pneumonia and COPD exacerbation.

Sci Rep 2020 01 14;10(1):241. Epub 2020 Jan 14.

Institute for Lung Research, Universities of Giessen and Marburg Lung Center, German Center for Lung Research (DZL), Marburg, Germany.

Lower respiratory infections, such as community-acquired pneumonia (CAP), and chronic obstructive pulmonary disease (COPD) rank among the most frequent causes of death worldwide. Improved diagnostics and profound pathophysiological insights are urgent clinical needs. In our cohort, we analysed transcriptional networks of peripheral blood mononuclear cells (PBMCs) to identify central regulators and potential biomarkers. We investigated the mRNA- and miRNA-transcriptome of PBMCs of healthy subjects and patients suffering from CAP or AECOPD by microarray and Taqman Low Density Array. Genes that correlated with PBMC composition were eliminated, and remaining differentially expressed genes were grouped into modules. One selected module (120 genes) was particularly suitable to discriminate AECOPD and CAP and most notably contained a subset of five biologically relevant mRNAs that differentiated between CAP and AECOPD with an AUC of 86.1%. Likewise, we identified several microRNAs, e.g. miR-545-3p and miR-519c-3p, which separated AECOPD and CAP. We furthermore retrieved an integrated network of differentially regulated mRNAs and microRNAs and identified HNF4A, MCC and MUC1 as central network regulators or most important discriminatory markers. In summary, transcriptional analysis retrieved potential biomarkers and central molecular features of CAP and AECOPD.
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http://dx.doi.org/10.1038/s41598-019-57108-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6959367PMC
January 2020

Antiviral potential of human IFN-α subtypes against influenza A H3N2 infection in human lung explants reveals subtype-specific activities.

Emerg Microbes Infect 2019 ;8(1):1763-1776

Institute of Virology Muenster, Westfaelische Wilhelms-University, Muenster, Germany.

Influenza is an acute respiratory infection causing high morbidity and mortality in annual outbreaks worldwide. Antiviral drugs are limited and pose the risk of resistance development, calling for new treatment options. IFN-α subtypes are immune-stimulatory cytokines with strong antiviral activities against IAV and However, the clinical use of IFN-α2, the only licensed subtype of this multi-gene family, could not prevent or limit IAV infections in humans. However, the other subtypes were not investigated.Therefore, this study evaluated the induction and antiviral potential of all human IFN-α subtypes during H3N2 IAV infection in human lung explants. We found that subtypes with weak antiviral activities were preferentially induced during IAV infection in human lungs. Intriguingly, non-induced subtypes α16, α5 and α4 suppressed viral replication up to 230-fold more efficiently than α2. Furthermore, our results demonstrate that subtypes with stronger antiviral activities induce higher expression of IAV-specific restriction factors and that MxA expression is a determinant of the subtype-specific antiviral activity towards H3N2 IAV. These results corroborate that IFN-α subtypes exhibit differential antiviral activities and emphasize that subtypes α16, α5 and α4 should be further investigated for the prevention and treatment of severe infections with seasonal H3N2 IAV.
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http://dx.doi.org/10.1080/22221751.2019.1698271DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6913622PMC
April 2020

Surface Proteome of Plasma Extracellular Vesicles as Biomarkers for Pneumonia and Acute Exacerbation of Chronic Obstructive Pulmonary Disease.

J Infect Dis 2020 01;221(2):325-335

Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, Member of the German Center for Lung Research, Marburg, Germany.

Background: Community-acquired pneumonia (CAP) and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) represent a major burden of disease and death and their differential diagnosis is critical. A potential source of relevant accessible biomarkers are blood-borne small extracellular vesicles (sEVs).

Methods: We performed an extracellular vesicle array to find proteins on plasma sEVs that are differentially expressed and possibly allow the differential diagnosis between CAP and AECOPD. Plasma samples were analyzed from 21 healthy controls, 24 patients with CAP, and 10 with AECOPD . The array contained 40 antibodies to capture sEVs, which were then visualized with a cocktail of biotin-conjugated CD9, CD63, and CD81 antibodies.

Results: We detected significant differences in the protein decoration of sEVs between healthy controls and patients with CAP or AECOPD. We found CD45 and CD28 to be the best discrimination markers between CAP and AECOPD in receiver operating characteristic analyses, with an area under the curve >0.92. Additional ensemble feature selection revealed the possibility to distinguish between CAP and AECOPD even if the patient with CAP had COPD, with a panel of CD45, CD28, CTLA4 (cytotoxic T-lymphocyte-associated protein 4), tumor necrosis factor-R-II, and CD16.

Conclusion: The discrimination of sEV-associated proteins is a minimally invasive method with potential to discriminate between CAP and AECOPD.
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http://dx.doi.org/10.1093/infdis/jiz460DOI Listing
January 2020

3D organ models-Revolution in pharmacological research?

Pharmacol Res 2019 01 3;139:446-451. Epub 2018 Nov 3.

Freie Universität Berlin, Institute for Pharmacy, Pharmacology & Toxicology, Königin-Luise-Str. 2-4, Berlin, 14195, Germany. Electronic address:

3D organ models have gained increasing attention as novel preclinical test systems and alternatives to animal testing. Over the years, many excellent in vitro tissue models have been developed. In parallel, microfluidic organ-on-a-chip tissue cultures have gained increasing interest for their ability to house several organ models on a single device and interlink these within a human-like environment. In contrast to these advancements, the development of human disease models is still in its infancy. Although major advances have recently been made, efforts still need to be intensified. Human disease models have proven valuable for their ability to closely mimic disease patterns in vitro, permitting the study of pathophysiological features and new treatment options. Although animal studies remain the gold standard for preclinical testing, they have major drawbacks such as high cost and ongoing controversy over their predictive value for several human conditions. Moreover, there is growing political and social pressure to develop alternatives to animal models, clearly promoting the search for valid, cost-efficient and easy-to-handle systems lacking interspecies-related differences. In this review, we discuss the current state of the art regarding 3D organ as well as the opportunities, limitations and future implications of their use.
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http://dx.doi.org/10.1016/j.phrs.2018.11.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7129286PMC
January 2019

Generation of a 3D Liver Model Comprising Human Extracellular Matrix in an Alginate/Gelatin-Based Bioink by Extrusion Bioprinting for Infection and Transduction Studies.

Int J Mol Sci 2018 Oct 12;19(10). Epub 2018 Oct 12.

Institute of Biotechnology, Department of Applied Biochemistry, Technische Universität Berlin, 13355 Berlin, Germany.

Bioprinting is a novel technology that may help to overcome limitations associated with two-dimensional (2D) cell cultures and animal experiments, as it allows the production of three-dimensional (3D) tissue models composed of human cells. The present study describes the optimization of a bioink composed of alginate, gelatin and human extracellular matrix (hECM) to print human HepaRG liver cells with a pneumatic extrusion printer. The resulting tissue model was tested for its suitability for the study of transduction by an adeno-associated virus (AAV) vector and infection with human adenovirus 5 (hAdV5). We found supplementation of the basic alginate/gelatin bioink with 0.5 and 1 mg/mL hECM provides desirable properties for the printing process, the stability of the printed constructs, and the viability and metabolic functions of the printed HepaRG cells. The tissue models were efficiently transduced by AAV vectors of serotype 6, which successfully silenced an endogenous target (cyclophilin B) by means of RNA interference. Furthermore, the printed 3D model supported efficient adenoviral replication making it suitable to study virus biology and develop new antiviral compounds. We consider the approach described here paradigmatic for the development of 3D tissue models for studies including viral vectors and infectious viruses.
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http://dx.doi.org/10.3390/ijms19103129DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213460PMC
October 2018

Optimization of cell-laden bioinks for 3D bioprinting and efficient infection with influenza A virus.

Sci Rep 2018 09 17;8(1):13877. Epub 2018 Sep 17.

Institute of Biotechnology, Department of Applied Biochemistry, Technische Universität Berlin, 13355, Berlin, Germany.

Bioprinting is a new technology, which arranges cells with high spatial resolution, but its potential to create models for viral infection studies has not yet been fully realized. The present study describes the optimization of a bioink composition for extrusion printing. The bioinks were biophysically characterized by rheological and electron micrographic measurements. Hydrogels consisting of alginate, gelatin and Matrigel were used to provide a scaffold for a 3D arrangement of human alveolar A549 cells. A blend containing 20% Matrigel provided the optimal conditions for spatial distribution and viability of the printed cells. Infection of the 3D model with a seasonal influenza A strain resulted in widespread distribution of the virus and a clustered infection pattern that is also observed in the natural lung but not in two-dimensional (2D) cell culture, which demonstrates the advantage of 3D printed constructs over conventional culture conditions. The bioink supported viral replication and proinflammatory interferon release of the infected cells. We consider our strategy to be paradigmatic for the generation of humanized 3D tissue models by bioprinting to study infections and develop new antiviral strategies.
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http://dx.doi.org/10.1038/s41598-018-31880-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6141611PMC
September 2018

A novel European H5N8 influenza A virus has increased virulence in ducks but low zoonotic potential.

Emerg Microbes Infect 2018 Jul 19;7(1):132. Epub 2018 Jul 19.

Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany.

We investigated in a unique setup of animal models and a human lung explant culture biological properties, including zoonotic potential, of a representative 2016 highly pathogenic avian influenza virus (HPAIV) H5N8, clade 2.3.4.4 group B (H5N8B), that spread rapidly in a huge and ongoing outbreak series in Europe and caused high mortality in waterfowl and domestic birds. HPAIV H5N8B showed increased virulence with rapid onset of severe disease and mortality in Pekin ducks due to pronounced neuro- and hepatotropism. Cross-species infection was evaluated in mice, ferrets, and in a human lung explant culture model. While the H5N8B isolate was highly virulent for Balb/c mice, virulence and transmissibility were grossly reduced in ferrets, which was mirrored by marginal replication in human lung cultures infected ex vivo. Our data indicate that the 2016 HPAIV H5N8B is avian-adapted with augmented virulence for waterfowl, but has low zoonotic potential. The here tested combination of animal studies with the inoculation of human explants provides a promising future workflow to evaluate zoonotic potential, mammalian replication competence and avian virulence of HPAIV.
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http://dx.doi.org/10.1038/s41426-018-0130-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6053424PMC
July 2018

DNA-release by Streptococcus pneumoniae autolysin LytA induced Krueppel-like factor 4 expression in macrophages.

Sci Rep 2018 04 10;8(1):5723. Epub 2018 Apr 10.

Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.

The recruitment of myeloid cells to the lung is of utmost importance for the elimination of invading pathogens. We investigated the Streptococcus pneumoniae-dependent induction mechanism of KLF4 in macrophages as a potential regulator of the macrophage immune response. We demonstrated that only viable pneumococci, which have direct contact to the host cells and release LytA-dependent DNA, induced KLF4. Exogenous supplementation of pneumococcal, other bacterial, eukaryotic foreign (human) or self (mouse) DNA to autolysis-deficient pneumococci restored (at least in part) pneumococci-related KLF4 induction. Experiments using TLR9, TRIF and MyD88 knockout macrophages revealed that TLR9, TRIF and MyD88 were partly involved in the S. pneumoniae-induced KLF4 expression. BMMs missing important DNA receptor related molecules (ASC, STING) showed no differences in pneumococci-related KLF4 expression. Similar results were observed with IFNAR BMMs and Type I IFN stimulated cells. LyzMcre mediated knockdown of KLF4 in BMMs resulted in a decreased secretion of proinflammatory cytokines and enhanced IL-10 release. In summary, we showed that pneumococci-related KLF4 induction in macrophages is mediated via a PAMP-DAMP induction mechanism involving a hitherto unknown host cell DNA sensor leading to a more proinflammatory macrophage phenotype.
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http://dx.doi.org/10.1038/s41598-018-24152-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5893607PMC
April 2018

Prognostic and Pathogenic Role of Angiopoietin-1 and -2 in Pneumonia.

Am J Respir Crit Care Med 2018 07;198(2):220-231

1 Division of Pulmonary Inflammation and.

Rationale: During pneumonia, pathogen-host interaction evokes inflammation and lung barrier dysfunction. Tie2 activation by angiopoietin-1 reduces, whereas Tie2 blockade by angiopoietin-2 increases, inflammation and permeability during sepsis. The role of angiopoietin-1/-2 in pneumonia remains unidentified.

Objectives: To investigate the prognostic and pathogenic impact of angiopoietins in regulating pulmonary vascular barrier function and inflammation in bacterial pneumonia.

Methods: Serum angiopoietin levels were quantified in pneumonia patients of two independent cohorts (n = 148, n = 395). Human postmortem lung tissue, pneumolysin- or angiopoietin-2-stimulated endothelial cells, isolated perfused and ventilated mouse lungs, and mice with pneumococcal pneumonia were investigated.

Measurements And Main Results: In patients with pneumonia, decreased serum angiopoietin-1 and increased angiopoietin-2 levels were observed as compared with healthy subjects. Higher angiopoietin-2 serum levels were found in patients with community-acquired pneumonia who died within 28 days of diagnosis compared with survivors. Receiver operating characteristic analysis revealed improved prognostic accuracy of CURB-65 for 28-day survival, intensive care treatment, and length of hospital stay if combined with angiopoietin-2 serum levels. In vitro, pneumolysin enhanced endothelial angiopoietin-2 release, angiopoietin-2 increased endothelial permeability, and angiopoietin-1 reduced pneumolysin-evoked endothelial permeability. Ventilated and perfused lungs of mice with angiopoietin-2 knockdown showed reduced permeability on pneumolysin stimulation. Increased pulmonary angiopoietin-2 and reduced angiopoietin-1 mRNA expression were observed in Streptococcus pneumoniae-infected mice. Finally, angiopoietin-1 therapy reduced inflammation and permeability in murine pneumonia.

Conclusions: These data suggest a central role of angiopoietin-1/-2 in pneumonia-evoked inflammation and permeability. Increased angiopoietin-2 serum levels predicted mortality and length of hospital stay, and angiopoietin-1 may provide a therapeutic target for severe pneumonia.
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http://dx.doi.org/10.1164/rccm.201708-1733OCDOI Listing
July 2018

Pneumolysin induced mitochondrial dysfunction leads to release of mitochondrial DNA.

Sci Rep 2018 01 9;8(1):182. Epub 2018 Jan 9.

Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.

Streptococcus pneumoniae (S.pn.) is the most common bacterial pathogen causing community acquired pneumonia. The pore-forming toxin pneumolysin (PLY) is the major virulence factor of S.pn. and supposed to affect alveolar epithelial cells thereby activating the immune system by liberation of danger-associated molecular patterns (DAMP). To test this hypothesis, we established a novel live-cell imaging based assay to analyse mitochondrial function and associated release of mitochondrial DNA (mtDNA) as DAMP in real-time. We first revealed that bacterially released PLY caused significant changes of the cellular ATP homeostasis and led to morphologic alterations of mitochondria in human alveolar epithelial cells in vitro and, by use of spectral live-tissue imaging, in human alveoli. This was accompanied by strong mitochondrial calcium influx and loss of mitochondrial membrane potential resulting in opening of the mitochondrial permeability transition pore and mtDNA release without activation of intrinsic apoptosis. Moreover, our data indicate cellular mtDNA liberation via microvesicles, which may contribute to S.pn. related pro-inflammatory immune activation in the human alveolar compartment.
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http://dx.doi.org/10.1038/s41598-017-18468-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5760655PMC
January 2018

Sphingosine Kinase 1 Regulates Inflammation and Contributes to Acute Lung Injury in Pneumococcal Pneumonia via the Sphingosine-1-Phosphate Receptor 2.

Crit Care Med 2018 03;46(3):e258-e267

Department of Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

Objectives: Severe pneumonia may evoke acute lung injury, and sphingosine-1-phosphate is involved in the regulation of vascular permeability and immune responses. However, the role of sphingosine-1-phosphate and the sphingosine-1-phosphate producing sphingosine kinase 1 in pneumonia remains elusive. We examined the role of the sphingosine-1-phosphate system in regulating pulmonary vascular barrier function in bacterial pneumonia.

Design: Controlled, in vitro, ex vivo, and in vivo laboratory study.

Subjects: Female wild-type and SphK1-deficient mice, 8-10 weeks old. Human postmortem lung tissue, human blood-derived macrophages, and pulmonary microvascular endothelial cells.

Interventions: Wild-type and SphK1-deficient mice were infected with Streptococcus pneumoniae. Pulmonary sphingosine-1-phosphate levels, messenger RNA expression, and permeability as well as lung morphology were analyzed. Human blood-derived macrophages and human pulmonary microvascular endothelial cells were infected with S. pneumoniae. Transcellular electrical resistance of human pulmonary microvascular endothelial cell monolayers was examined. Further, permeability of murine isolated perfused lungs was determined following exposition to sphingosine-1-phosphate and pneumolysin.

Measurements And Main Results: Following S. pneumoniae infection, murine pulmonary sphingosine-1-phosphate levels and sphingosine kinase 1 and sphingosine-1-phosphate receptor 2 expression were increased. Pneumonia-induced lung hyperpermeability was reduced in SphK1 mice compared with wild-type mice. Expression of sphingosine kinase 1 in macrophages recruited to inflamed lung areas in pneumonia was observed in murine and human lungs. S. pneumoniae induced the sphingosine kinase 1/sphingosine-1-phosphate system in blood-derived macrophages and enhanced sphingosine-1-phosphate receptor 2 expression in human pulmonary microvascular endothelial cell in vitro. In isolated mouse lungs, pneumolysin-induced hyperpermeability was dose dependently and synergistically increased by sphingosine-1-phosphate. This sphingosine-1-phosphate-induced increase was reduced by inhibition of sphingosine-1-phosphate receptor 2 or its downstream effector Rho-kinase.

Conclusions: Our data suggest that targeting the sphingosine kinase 1-/sphingosine-1-phosphate-/sphingosine-1-phosphate receptor 2-signaling pathway in the lung may provide a novel therapeutic perspective in pneumococcal pneumonia for prevention of acute lung injury.
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http://dx.doi.org/10.1097/CCM.0000000000002916DOI Listing
March 2018

THP-1-derived macrophages render lung epithelial cells hypo-responsive to Legionella pneumophila - a systems biology study.

Sci Rep 2017 09 20;7(1):11988. Epub 2017 Sep 20.

Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, Member of the German Center for Lung Research (DZL), Marburg, Germany.

Immune response in the lung has to protect the huge alveolar surface against pathogens while securing the delicate lung structure. Macrophages and alveolar epithelial cells constitute the first line of defense and together orchestrate the initial steps of host defense. In this study, we analysed the influence of macrophages on type II alveolar epithelial cells during Legionella pneumophila-infection by a systems biology approach combining experimental work and mathematical modelling. We found that L. pneumophila-infected THP-1-derived macrophages provoke a pro-inflammatory activation of neighboring lung epithelial cells, but in addition render them hypo-responsive to direct infection with the same pathogen. We generated a kinetic mathematical model of macrophage activation and identified a paracrine mechanism of macrophage-secreted IL-1β inducing a prolonged IRAK-1 degradation in lung epithelial cells. This intercellular crosstalk may help to avoid an overwhelming inflammatory response by preventing excessive local secretion of pro-inflammatory cytokines and thereby negatively regulating the recruitment of immune cells to the site of infection. This suggests an important but ambivalent immunomodulatory role of macrophages in lung infection.
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http://dx.doi.org/10.1038/s41598-017-12154-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5607273PMC
September 2017

Human Pulmonary 3D Models For Translational Research.

Biotechnol J 2018 Jan 20;13(1). Epub 2017 Sep 20.

Dept. of Internal Medicine/Infectious and Respiratory Diseases, Charité - Universitätsmedizin Berlin, Charitèplatz 1, Berlin 10117, Germany.

Lung diseases belong to the major causes of death worldwide. Recent innovative methodological developments now allow more and more for the use of primary human tissue and cells to model such diseases. In this regard, the review covers bronchial air-liquid interface cultures, precision cut lung slices as well as ex vivo cultures of explanted peripheral lung tissue and de-/re-cellularization models. Diseases such as asthma or infections are discussed and an outlook on further areas for development is given. Overall, the progress in ex vivo modeling by using primary human material could make translational research activities more efficient by simultaneously fostering the mechanistic understanding of human lung diseases while reducing animal usage in biomedical research.
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http://dx.doi.org/10.1002/biot.201700341DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7161817PMC
January 2018

Tyk2 as a target for immune regulation in human viral/bacterial pneumonia.

Eur Respir J 2017 07 13;50(1). Epub 2017 Jul 13.

Dept of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany

The severity and lethality of influenza A virus (IAV) infections is frequently aggravated by secondary bacterial pneumonia. However, the mechanisms in human lung tissue that provoke this increase in fatality are unknown and therapeutic immune modulatory options are lacking.We established a human lung co-infection model to investigate innate immune related mechanisms contributing to the susceptibility of secondary pneumococcal pneumonia.We revealed that type I and III interferon (IFN) inhibits -induced interleukin (IL)-1β release. The lack of IL-1β resulted in the repression of bacterially induced granulocyte-macrophage colony-stimulating factor (GM-CSF) liberation. Specific inhibition of IFN receptor I and III-associated tyrosine kinase 2 (Tyk2) completely restored the -induced IL-1β-GM-CSF axis, leading to a reduction of bacterial growth. A preceding IAV infection of the human alveolus leads to a type I and III IFN-dependent blockade of the early cytokines IL-1β and GM-CSF, which are key for orchestrating an adequate innate immune response against bacteria. Their virally induced suppression may result in impaired bacterial clearance and alveolar repair.Pharmacological inhibition of Tyk2 might be a new treatment option to sustain beneficial endogenous GM-CSF levels in IAV-associated secondary bacterial pneumonia.
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http://dx.doi.org/10.1183/13993003.01953-2016DOI Listing
July 2017

Localization and pneumococcal alteration of junction proteins in the human alveolar-capillary compartment.

Histochem Cell Biol 2017 Jun 1;147(6):707-719. Epub 2017 Mar 1.

Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.

Loss of alveolar barrier function with subsequent respiratory failure is a hallmark of severe pneumonia. Although junctions between endo- and epithelial cells regulate paracellular fluid flux, little is known about their composition and regulation in the human alveolar compartment. High autofluorescence of human lung tissue in particular complicates the determination of subcellular protein localization. By comparing conventional channel mode confocal imaging with spectral imaging and linear unmixing, we demonstrate that background fluorescent spectra and fluorophore signals could be rigorously separated resulting in complete recovery of the specific signal at a high signal-to-noise ratio. Using this technique and Western blotting, we show the expression patterns of tight junction proteins occludin, ZO-1 as well as claudin-3, -4, -5 and -18 and adherence junction protein VE-cadherin in naive or Streptococcus pneumoniae-infected human lung tissue. In uninfected tissues, occludin and ZO-1 formed band-like structures in alveolar epithelial cells type I (AEC I), alveolar epithelial cells type II (AEC II) and lung capillaries, whereas claudin-3, -4 and -18 were visualised in AEC II. Claudin-5 was detected in the endothelium only. Claudin-3, -5, -18 displayed continuous band-like structures, while claudin-4 showed a dot-like expression. Pneumococcal infection reduced alveolar occludin, ZO-1, claudin-5 and VE-cadherin but did not change the presence of claudin-3, -4 and -18. Spectral confocal microscopy allows for the subcellular structural analysis of proteins in highly autofluorescent human lung tissue. The thereby observed deterioration of lung alveolar junctional organisation gives a structural explanation for alveolar barrier disruption in severe pneumococcal pneumonia.
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http://dx.doi.org/10.1007/s00418-017-1551-yDOI Listing
June 2017

Human lung ex vivo infection models.

Cell Tissue Res 2017 03 20;367(3):511-524. Epub 2016 Dec 20.

Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.

Pneumonia is counted among the leading causes of death worldwide. Viruses, bacteria and pathogen-related molecules interact with cells present in the human alveolus by numerous, yet poorly understood ways. Traditional cell culture models little reflect the cellular composition, matrix complexity and three-dimensional architecture of the human lung. Integrative animal models suffer from species differences, which are of particular importance for the investigation of zoonotic lung diseases. The use of cultured ex vivo infected human lung tissue may overcome some of these limitations and complement traditional models. The present review gives an overview of common bacterial lung infections, such as pneumococcal infection and of widely neglected pathogens modeled in ex vivo infected lung tissue. The role of ex vivo infected lung tissue for the investigation of emerging viral zoonosis including influenza A virus and Middle East respiratory syndrome coronavirus is discussed. Finally, further directions for the elaboration of such models are revealed. Overall, the introduced models represent meaningful and robust methods to investigate principles of pathogen-host interaction in original human lung tissue.
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http://dx.doi.org/10.1007/s00441-016-2546-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7087833PMC
March 2017

Lung perfusion and emphysema distribution affect the outcome of endobronchial valve therapy.

Int J Chron Obstruct Pulmon Dis 2016 9;11:1245-59. Epub 2016 Jun 9.

Department of Internal Medicine/Infectious Diseases and Respiratory Medicine.

The exclusion of collateral ventilation (CV) and other factors affect the clinical success of endoscopic lung volume reduction (ELVR). However, despite its benefits, the outcome of ELVR remains difficult to predict. We investigated whether clinical success could be predicted by emphysema distribution assessed by computed tomography scan and baseline perfusion assessed by perfusion scintigraphy. Data from 57 patients with no CV in the target lobe (TL) were retrospectively analyzed after ELVR with valves. Pulmonary function tests (PFT), St George's Respiratory Questionnaire (SGRQ), and 6-minute walk tests (6MWT) were performed on patients at baseline. The sample was grouped into high and low levels at the median of TL perfusion, ipsilateral nontarget lobe (INL) perfusion, and heterogeneity index (HI). These groups were analyzed for association with changes in outcome parameters from baseline to 3 months follow-up. Compared to baseline, patients showed significant improvements in PFT, SGRQ, and 6MWT (all P≤0.001). TL perfusion was not associated with changes in the outcome. High INL perfusion was significantly associated with increases in 6MWT (P=0.014), and high HI was associated with increases in forced expiratory volume in 1 second (FEV1), (P=0.012). Likewise, there were significant correlations for INL perfusion and improvement of 6MWT (r=0.35, P=0.03) and for HI and improvement in FEV1 (r=0.45, P=0.001). This study reveals new attributes that associate with positive outcomes for patient selection prior to ELVR. Patients with high perfusions in INL demonstrated greater improvements in 6MWT, while patients with high HI were more likely to respond in FEV1.
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http://dx.doi.org/10.2147/COPD.S101003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4907487PMC
August 2017

MicroRNAs Constitute a Negative Feedback Loop in Streptococcus pneumoniae-Induced Macrophage Activation.

J Infect Dis 2016 07 16;214(2):288-99. Epub 2016 Mar 16.

Institute for Lung Research, German Center for Lung Research, Universities of Giessen and Marburg Lung Center Department of Medicine, Pulmonary and Critical Care Medicine, University Medical Center Giessen and Marburg, Philipps-University Marburg.

Streptococcus pneumoniae causes high mortality as a major pneumonia-inducing pathogen. In pneumonia, control of innate immunity is necessary to prevent organ damage. We assessed the role of microRNAs (miRNAs) as regulators in pneumococcal infection of human macrophages. Exposure of primary blood-derived human macrophages with pneumococci resulted in transcriptional changes in several gene clusters and a significant deregulation of 10 microRNAs. Computational network analysis retrieved miRNA-146a as one putatively important regulator of pneumococci-induced host cell activation. Its induction depended on bacterial structural integrity and was completely inhibited by blocking Toll-like receptor 2 (TLR-2) or depleting its mediator MyD88. Furthermore, induction of miRNA-146a release did not require the autocrine feedback of interleukin 1β and tumor necrosis factor α released from infected macrophages, and it repressed the TLR-2 downstream mediators IRAK-1 and TRAF-6, as well as the inflammatory factors cyclooxygenase 2 and interleukin 1β. In summary, pneumococci recognition induces a negative feedback loop, preventing excessive inflammation via miR-146a and potentially other miRNAs.
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http://dx.doi.org/10.1093/infdis/jiw109DOI Listing
July 2016