22 results on '"Röhm M"'
Search Results
2. Innovationen multi-perspektiv entwickeln*/Multi-perspective development of innovations - Holistic view of innovation processes for the derivation of manufacturing strategic decision areas
- Author
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Röhm, M., primary, Bauernhansl, T. Prof., additional, and Schrodi, T., additional
- Published
- 2017
- Full Text
- View/download PDF
3. Charakterisierung einer Familie von Pry-Proteinen in Candida albicans
- Author
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Röhm, M. and Brunner, Herwig (Prof. Dr.)
- Subjects
Sekretom , PRY-Proteine (pathogenesis-related in yeast) , CAP-Protein-Superfamilie ,Candida albicans , Pathogener Mikroorganismus , Virulenz , Virulenzfaktor ,CAP protein superfamily , pathogenesis-related 1 (PR-1) protein family , RBE1 , RBT4 - Abstract
Die Mitglieder der Superfamilie der CAP-Proteine sind ubiquitär verbreitet und zeichnen sich durch eine konservierte zentrale Domäne aus, die ihnen eine außerordentlich stabile drei-dimensionale Struktur verleiht und die den strukturellen Anforderungen extrazellulär wirkender Proteine entspricht. Der Grad der Sequenz- und Strukturhomologien dieser Proteine deutet auf einen ähnlichen Wirkmechanismus hin, die molekulare Funktion der CAP-Proteine ist bis heute jedoch unklar. In dieser Arbeit wurde eine bisher nicht beschriebene Familie von CAP-Proteinen in C. albicans identifiziert und deren Mitglieder funktionell charakterisiert. In Analogie zu S. cerevisiae sollen diese als Pry-Proteine bezeichnet werden (pathogenesis-related in yeast). Die Pry-Proteinfamilie in C. albicans umfasst 5 Mitglieder, die im Zusammenhang mit der Morphogenese von C. albicans (Hefe – Hyphe, white – opaque) differentiell reguliert sind. Alle 5 Familienmitglieder weisen spezifische strukturelle Merkmale sekretierter Proteine auf. Transkriptionelle Studien zeigen, dass die beiden Pry-Proteine Rbe1p und Rbt4p von den zentralen Regulatoren der Morphogenese in C. albicans, Efg1p und Tup1p, gegensätzlich reguliert werden. Dabei wird Rbe1p v.a. in Blastosporen und opaque-Zellen, Rbt4p degegen in Hyphen exprimiert. Die Promotorsequenz von RBE1 umfasst 1039 bp und enthält eine aktivierende und eine reprimierende Domäne für die Transkription. Obwohl diese mehrere mögliche Bindestellen für Efg1p aufweisen, bindet heterolog exprimiertes Efg1p offensichtlich nicht an den RBE1-Promotor, so dass die Regulation von RBE1 voraussichtlich indirekt durch Efg1p erfolgt. Massenspektrometrische Analysen des C. albicans-Sekretoms weisen Rbe1p und Rbt4p als sekretierte Proteine in C. albicans aus. Dabei ist Rbe1p ein spezifisch von Blastosporen sekretiertes Protein, während Rbt4p ein Bestandteil des Sekretoms von Blastosporen und Hyphen ist. Heterolog exprimiertes Rbe1p und Rbt4p zeigen keine für die CAP-Proteine postulierte Funktion als Protease. Deletionsstudien für RBE1 und RBT4 in SC5314 zeigen keinen Phänotyp auf gängigen Labormedien, sowie keine Beteiligung an der Adhäsion und Invasion humanen Epithelgewebes. In Kombination führt die Deletion beider Gene allerdings zu einer starken Attenuation der Virulenz in einem intravenösen Mausmodell für systemische Kandidosen. Diese tritt bei einer Deletion nur eines der beiden PRY-Gene nur schwach zutage, da in diesen Stämmen das jeweils andere PRY-Gen kompensatorisch induziert wird. Dieser synergistische Virulenzphänotyp spricht für eine ähnliche Funktion der beiden Proteine sowie für eine Regulation durch ähnliche Signalwege., The members of the CAP superfamily of proteins are disseminated in a widespread range of organisms of all kingdoms and are characterized by a conserved central domain that accounts for an extraordinary stable three-dimensional structure, meeting the structural requirements for proteins functioning in the extracellular environment. The PR-1 (pathogenesis-related) subfamily of these proteins has already been described in plants as being expressed in response to challenge with pathogens. The degree of sequence and structural homologies between these proteins points to a similar mode of action, yet the molecular function of the CAP proteins is not known. Based on database searches, we identified a similar family of proteins in C. albicans comprising five members with homology to PR-1 proteins in plants. In addition to RBE1 and RBT4, we could assign three yet not further characterized open reading frames, ORF19.6200, ORF19.2787 as well as ORF19.2336, to this family of proteins. In analogy to S. cerevisiae, the members of this family are termed Pry proteins (pathogenesis-related in yeast). Structurally, all of these proteins dispose of characteristics of secreted proteins. RBE1 is expressed in blastospores and opaque cells and is downregulated in hyphae. On the contrary, RBT4 is upregulated in hyphae compared to blastospores and downregulated in opaque cells. Transcript levels for the other family members are generally low under these conditions. Transcription of RBE1 and RBT4 is repressed by EFG1 and TUP1, respectively, thus accomplishing their morphogenesis-related expression. Mass spectrometric analyses of the C. albicans secretome show that both Rbe1p and Rbt4p are secretory proteins in C. albicans. Rbe1p is secreted specifically by yeast cells, whereas Rbt4p is secreted by both yeast and hyphal cells. Single deletion mutants of RBE1 and RBT4 as well as the corresponding Δrbe1/Δrbt4 double mutant in the clinical isolate SC5314 do not show any obvious phenotype under common morphogenesis-inducing conditions. Moreover, no significant differences were found in in vitro adhesion and invasion assays employing different cellular epithelia in comparison to the wildtype. However, applying a mouse model for disseminated candidiasis, the Δrbe1 and Δrbt4 single deletion strains showed a moderate but significant virulence phenotype. A synergistic effect was observed in the Δrbe1/Δrbt4 double mutant for which virulence was strongly attenuated. Strikingly, RBE1 transcript levels are upregulated in the Δrbt4 mutant strain and vice versa, indicating that both proteins share similar molecular functions or are implicated in similar physiological processes critical for virulence in vivo.
- Published
- 2010
4. Digging deep into the data mine with DataMiningGrid
- Author
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Stankovski, V., Swain, M., Niessen, T., Wegener, Dennis, Röhm, M., Trnkoczy, J., May, Michael, Franke, J., Schuster, A., Dubitzky, W., and Publica
- Abstract
As modern data mining applications increase in complexity, so too do their demands for resources. Grid computing is one of several emerging networked computing paradigms promising to meet the requirements of heterogeneous, large-scale, and distributed data mining applications. Despite this promise, there are still too many issues to be resolved before grid technology is commonly applied to large-scale data mining tasks. To address some of these issues, the authors developed the DataMiningGrid system. It integrates a diverse set of programs and application scenarios within a single framework, and features scalability, flexible extensibility, sophisticated support for relevant standards and different users.
- Published
- 2008
5. Identification and Characterization of Cor33p, a novel protein implicated in tolerance towards oxidative stress in Candida albicans
- Author
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Sohn, K., Röhm, M., Urban, C.F., Saunders, N., Rothenstein, D., Lottspeich, F., Schröppel, K., Rupp, S., and Publica
- Abstract
We applied two-dimensional gel electrophoresis to identify downstream effectors of CPH1 and EFG1 under hypha-inducing conditions in Candida albicans. Among the proteins that were expressed in wild-type cells but were strongly downregulated in a cph1 Delta/efg1 Delta double mutant in alpha-minimal essential medium at 37 degrees C, we could identify not-yet-characterized proteins, including Cor33-1p and Cor33-2p. The two proteins are almost identical (97% identity) and represent products of allelic isoforms of the same gene. Cor33p is highly similar to Cip1p from Candida sp. but lacks any significant homology to proteins from Saccharomyces cerevisiae. Strikingly, both proteins share homology with phenylcoumaran benzylic ether reductases and isoflavone reductases from plants. For other hypha-inducing media, like yeast-peptone-dextrose (YPD) plus serum at 37 degrees C, we could not detect any transcription for COR33 in wild-type cells, indicating that Cor33p is not hypha specific. In contrast, we found a strong induction for COR33 when cells were treated with 5 mM hydrogen peroxide. However, under oxidative conditions, transcription of COR33 was not dependent on EFG1, indicating that other regulatory factors are involved. In fact, upregulation depends on CAP1 at least, as transcript levels were clearly reduced in a Delta cap1 mutant strain under oxidative conditions. Unlike in wild-type cells, transcription of COR33 in a tsa1 Delta mutant can be induced by treatment with 0.1 mM hydrogen peroxide. This suggests a functional link between COR33 and thiol-specific antioxidant-like proteins that are important in the oxidative-stress response in yeasts. Concordantly, cor33 Delta deletion mutants show retarded growth on YPD plates supplemented with hydrogen peroxide, indicating that COR33 in general is implicated in conferring tolerance toward oxidative stress on Candida albicans.
- Published
- 2005
6. A family of secreted pathogenesis‐related proteins in Candida albicans
- Author
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Röhm, M., primary, Lindemann, E., additional, Hiller, E., additional, Ermert, D., additional, Lemuth, K., additional, Trkulja, D., additional, Sogukpinar, O., additional, Brunner, H., additional, Rupp, S., additional, Urban, C. F., additional, and Sohn, K., additional
- Published
- 2012
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7. Stoffübergang in Flüssig-flüssig-Systemen durch Grenzflächenkonvektion (Eruptionen).
- Author
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Fitzer, E., Fritz, W., Röhm, M., and El Deen, A. Zein
- Published
- 1967
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8. A Novel MATLAB®-Algorithm-Based Video Analysis to Quantitatively Determine Solution Creeping in Intact Pharmaceutical Glass Vials.
- Author
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Molnar D, Röhm M, Wutz J, Rivec I, Michel A, Klotz G, Hubbuch J, Schindowski K, and Presser I
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- Algorithms, Freeze Drying, Pharmaceutical Preparations, Drug Packaging methods, Glass
- Abstract
During the filling process of a biopharmaceutical drug product (DP), a liquid DP film might creep up the inner vial wall which is barely discernible, appears as milky-white haze after lyophilisation and is known as fogging. Creeping and fogging are mainly dependent on the primary packaging material surface and its hydration, vial preparation process as well as DP composition. The occurrence of both can impede visual inspection and might lead to DP rejection. Hence, our studies focused on the early detection of liquid solution and glass vial surface interaction directly after filling. For a fast and highly sensitive evaluation a novel video-based analysis was used. To our knowledge, this is the first time a MATLAB®-algorithm-based video analysis was applied to quantitatively determine creeping time-resolved. Furthermore, creeping in dependence of vial processing sites, surfactant type and concentration, filling temperature, and vial format were investigated. The results were verified using orthogonal conventional methods such as surface tension, wetting behaviour, and contact angle measurements, as well as ToF-SIMS, ICP-MS, and SEM. Additionally, the methods applied were assessed regarding their cross-validation capability. The observations indicate that the vial preparation process can have a pronounced impact on alteration of the glass vial surface and related creeping behaviour of the filled solution., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2022
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9. The role of resources in the face of psychopathology.
- Author
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Goldbach N, Reif A, Preuss H, Röhm M, Straus E, Streicher E, Windmann S, and Oertel V
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- Adult, Female, Humans, Male, Middle Aged, Psychopathology, Psychotherapy, Surveys and Questionnaires, Depressive Disorder psychology, Healthy Volunteers psychology, Interpersonal Relations, Psychological Distress, Psychotic Disorders psychology, Resilience, Psychological, Substance-Related Disorders psychology
- Abstract
Objectives: The current study compared resource realization and psychological distress in patients with different psychiatric diagnoses and healthy individuals and examined the moderating effect of intrapersonal resources (personal strengths) and interpersonal resources (relationships) on the association between incongruence (unsatisfactory realization of personal goals) and psychological distress., Method: In total, 218 participants (45.87% female, mean age = 39.83 years) completed standardized questionnaires at one measurement point., Results: Healthy individuals (n = 56) reported the most resources, followed by patients with psychotic (n = 53), substance use (n = 53), and depressive disorders (n = 56). While patients with psychotic disorders benefited from intra- and interpersonal resources, patients with depression only benefitted from intrapersonal resources. Patients with substance use disorders did not benefit from resources at all., Conclusions: Depending on the diagnosis, patients evaluated their level of resources differently and benefitted in different ways. The results suggest that within psychotherapy, it might be useful to strengthen resources, especially for patients with depressive and substance use disorders., (© 2019 The Authors. Journal of Clinical Psychology Published by Wiley Periodicals, Inc.)
- Published
- 2020
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10. Laminar specificity of oscillatory coherence in the auditory cortex.
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García-Rosales F, Röhrig D, Weineck K, Röhm M, Lin YH, Cabral-Calderin Y, Kössl M, and Hechavarria JC
- Subjects
- Acoustic Stimulation, Action Potentials, Animals, Cortical Synchronization, Delta Rhythm, Male, Theta Rhythm, Vocalization, Animal, Auditory Cortex physiology, Auditory Perception physiology, Brain Waves, Chiroptera physiology, Neurons physiology
- Abstract
Empirical evidence suggests that, in the auditory cortex (AC), the phase relationship between spikes and local-field potentials (LFPs) plays an important role in the processing of auditory stimuli. Nevertheless, unlike the case of other sensory systems, it remains largely unexplored in the auditory modality whether the properties of the cortical columnar microcircuit shape the dynamics of spike-LFP coherence in a layer-specific manner. In this study, we directly tackle this issue by addressing whether spike-LFP and LFP-stimulus phase synchronization are spatially distributed in the AC during sensory processing, by performing laminar recordings in the cortex of awake short-tailed bats (Carollia perspicillata) while animals listened to conspecific distress vocalizations. We show that, in the AC, spike-LFP and LFP-stimulus synchrony depend significantly on cortical depth, and that sensory stimulation alters the spatial and spectral patterns of spike-LFP phase-locking. We argue that such laminar distribution of coherence could have functional implications for the representation of naturalistic auditory stimuli at a cortical level.
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- 2019
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11. Assessment of Neutrophil Chemotaxis Upon G-CSF Treatment of Healthy Stem Cell Donors and in Allogeneic Transplant Recipients.
- Author
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Thunström Salzer A, Niemiec MJ, Hosseinzadeh A, Stylianou M, Åström F, Röhm M, Ahlm C, Wahlin A, Ermert D, and Urban CF
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- Adult, Female, Humans, Male, Middle Aged, Phagocytosis drug effects, Respiratory Burst drug effects, Chemotaxis drug effects, Filgrastim administration & dosage, Hematopoietic Stem Cell Transplantation, Hematopoietic Stem Cells metabolism, Neutrophils metabolism, Tissue Donors
- Abstract
Neutrophils are crucial for the human innate immunity and constitute the majority of leukocytes in circulation. Thus, blood neutrophil counts serve as a measure for the immune system's functionality. Hematological patients often have low neutrophil counts due to disease or chemotherapy. To increase neutrophil counts and thereby preventing infections in high-risk patients, recombinant G-CSF is widely used as adjunct therapy to stimulate the maturation of neutrophils. In addition, G-CSF is utilized to recruit stem cells (SCs) into the peripheral blood of SC donors. Still, the actual functionality of neutrophils resulting from G-CSF treatment remains insufficiently understood. We tested the ex vivo functionality of neutrophils isolated from blood of G-CSF-treated healthy SC donors. We quantified chemotaxis, oxidative burst, and phagocytosis before and after treatment and detected significantly reduced chemotactic activity upon G-CSF treatment. Similarly, in vitro treatment of previously untreated neutrophils with G-CSF led to reduced chemotactic activity. In addition, we revealed that this effect persists in the allogeneic SC recipients up to 4 weeks after neutrophil engraftment. Our data indicates that neutrophil quantity, as a sole measure of immunocompetence in high-risk patients should be considered cautiously as neutrophil functionality might be affected by the primary treatment.
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- 2018
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12. A comprehensive screening platform for aerosolizable protein formulations for intranasal and pulmonary drug delivery.
- Author
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Röhm M, Carle S, Maigler F, Flamm J, Kramer V, Mavoungou C, Schmid O, and Schindowski K
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- Cell Line, Chemistry, Pharmaceutical, Epithelial Cells drug effects, Excipients chemistry, Humans, Immunoglobulin Fab Fragments administration & dosage, Immunoglobulin G administration & dosage, Administration, Intranasal, Aerosols, Drug Delivery Systems, Proteins administration & dosage
- Abstract
Aerosolized administration of biopharmaceuticals to the airways is a promising route for nasal and pulmonary drug delivery, but - in contrast to small molecules - little is known about the effects of aerosolization on safety and efficacy of biopharmaceuticals. Proteins are sensitive against aerosolization-associated shear stress. Tailored formulations can shield proteins and enhance permeation, but formulation development requires extensive screening approaches. Thus, the aim of this study was to develop a cell-based in vitro technology platform that includes screening of protein quality after aerosolization and transepithelial permeation. For efficient screening, a previously published aerosolization-surrogate assay was used in a design of experiments approach to screen suitable formulations for an IgG and its antigen-binding fragment (Fab) as exemplary biopharmaceuticals. Efficient, dose-controlled aerosol-cell delivery was performed with the ALICE-CLOUD system containing RPMI 2650 epithelial cells at the air-liquid interface. We could demonstrate that our technology platform allows for rapid and efficient screening of formulations consisting of different excipients (here: arginine, cyclodextrin, polysorbate, sorbitol, and trehalose) to minimize aerosolization-induced protein aggregation and maximize permeation through an in vitro epithelial cell barrier. Formulations reduced aggregation of native Fab and IgG relative to vehicle up to 50% and enhanced transepithelial permeation rate up to 2.8-fold., (Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.)
- Published
- 2017
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13. High-throughput analysis of sub-visible mAb aggregate particles using automated fluorescence microscopy imaging.
- Author
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Paul AJ, Bickel F, Röhm M, Hospach L, Halder B, Rettich N, Handrick R, Herold EM, Kiefer H, and Hesse F
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- Aerosols chemistry, Anilino Naphthalenesulfonates chemistry, Chromatography, High Pressure Liquid, Fluorescent Dyes chemistry, Freezing, High-Throughput Screening Assays methods, Optical Imaging methods, Antibodies, Monoclonal analysis, Microscopy, Fluorescence methods, Protein Aggregates
- Abstract
Aggregation of therapeutic proteins is a major concern as aggregates lower the yield and can impact the efficacy of the drug as well as the patient's safety. It can occur in all production stages; thus, it is essential to perform a detailed analysis for protein aggregates. Several methods such as size exclusion high-performance liquid chromatography (SE-HPLC), light scattering, turbidity, light obscuration, and microscopy-based approaches are used to analyze aggregates. None of these methods allows determination of all types of higher molecular weight (HMW) species due to a limited size range. Furthermore, quantification and specification of different HMW species are often not possible. Moreover, automation is a perspective challenge coming up with automated robotic laboratory systems. Hence, there is a need for a fast, high-throughput-compatible method, which can detect a broad size range and enable quantification and classification. We describe a novel approach for the detection of aggregates in the size range 1 to 1000 μm combining fluorescent dyes for protein aggregate labelling and automated fluorescence microscope imaging (aFMI). After appropriate selection of the dye and method optimization, our method enabled us to detect various types of HMW species of monoclonal antibodies (mAbs). Using 10 μmol L
-1 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonate (Bis-ANS) in combination with aFMI allowed the analysis of mAb aggregates induced by different stresses occurring during downstream processing, storage, and administration. Validation of our results was performed by SE-HPLC, UV-Vis spectroscopy, and dynamic light scattering. With this new approach, we could not only reliably detect different HMW species but also quantify and classify them in an automated approach. Our method achieves high-throughput requirements and the selection of various fluorescent dyes enables a broad range of applications.- Published
- 2017
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14. Data of rational process optimization for the production of a full IgG and its Fab fragment from hybridoma cells.
- Author
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Röhm M, Handl A, König M, Mavoungou C, Handrick R, and Schindowski K
- Abstract
This data article focuses on the production of monoclonal antibodies (mAb) and their fragments Fab and F(ab')2. Here, we present the data of an optimization protocol to improve the product yield of a hybridoma cell process using a Design of Experiment (DoE) strategy. Furthermore, the data of the evaluated conditions were used to test feeding strategies in shake flasks. They were verified in controlled 2 L fed-batch bioreactor processes. Supplementing the culture medium with human insulin-like growth factor-I (IGF-I) and Pluronic F-68, as well as a nutrient rich additive for fed-batch, resulted in improved cell growth correlating with a 7 day elongated process time and a 4.5 fold higher product titer. Finally, a rapid Fab generation protocol and the respective data are presented using different papain digestion and a camelid anti-kappa light chain VHH affinity ligand.
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- 2016
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15. First Steps to Develop and Validate a CFPD Model in Order to Support the Design of Nose-to-Brain Delivered Biopharmaceuticals.
- Author
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Engelhardt L, Röhm M, Mavoungou C, Schindowski K, Schafmeister A, and Simon U
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- Administration, Intranasal, Aerosols, Female, Humans, Kinetics, Male, Nasal Cavity anatomy & histology, Nasal Cavity diagnostic imaging, Numerical Analysis, Computer-Assisted, Particle Size, Permeability, Pharmaceutical Preparations chemistry, Pharmaceutical Preparations metabolism, Rheology, Tomography, X-Ray Computed, Biopharmaceutics methods, Computer Simulation, Models, Anatomic, Models, Biological, Nasal Absorption, Nasal Cavity metabolism, Olfactory Bulb metabolism, Pharmaceutical Preparations administration & dosage, Technology, Pharmaceutical methods
- Abstract
Purpose: Aerosol particle deposition in the human nasal cavity is of high interest in particular for intranasal central nervous system (CNS) drug delivery via the olfactory cleft. The objective of this study was the development and comparison of a numerical and experimental model to investigate various parameters for olfactory particle deposition within the complex anatomical nasal geometry., Methods: Based on a standardized nasal cavity, a computational fluid and particle dynamics (CFPD) model was developed that enables the variation and optimization of different parameters, which were validated by in vitro experiments using a constructed rapid-prototyped human nose model., Results: For various flow rates (5 to 40 l/min) and particle sizes (1 to 10 μm), the airflow velocities, the calculated particle airflow patterns and the particle deposition correlated very well with the experiment. Particle deposition was investigated numerically by varying particle sizes at constant flow rate and vice versa assuming the particle size distribution of the used nebulizer., Conclusions: The developed CFPD model could be directly translated to the in vitro results. Hence, it can be applied for parameter screening and will contribute to the improvement of aerosol particle deposition at the olfactory cleft for CNS drug delivery in particular for biopharmaceuticals.
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- 2016
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16. Recognition of Aspergillus fumigatus hyphae by human plasmacytoid dendritic cells is mediated by dectin-2 and results in formation of extracellular traps.
- Author
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Loures FV, Röhm M, Lee CK, Santos E, Wang JP, Specht CA, Calich VL, Urban CF, and Levitz SM
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- Aspergillosis genetics, Aspergillus fumigatus immunology, Cells, Cultured, Enzyme-Linked Immunosorbent Assay, Gene Expression Regulation immunology, Humans, Hyphae immunology, Microscopy, Confocal, Microscopy, Electron, Scanning, Oligonucleotide Array Sequence Analysis, Aspergillosis immunology, Dendritic Cells immunology, Extracellular Traps immunology, Lectins, C-Type immunology
- Abstract
Plasmacytoid dendritic cells (pDCs) were initially considered as critical for innate immunity to viruses. However, our group has shown that pDCs bind to and inhibit the growth of Aspergillus fumigatus hyphae and that depletion of pDCs renders mice hypersusceptible to experimental aspergillosis. In this study, we examined pDC receptors contributing to hyphal recognition and downstream events in pDCs stimulated by A. fumigatus hyphae. Our data show that Dectin-2, but not Dectin-1, participates in A. fumigatus hyphal recognition, TNF-α and IFN-α release, and antifungal activity. Moreover, Dectin-2 acts in cooperation with the FcRγ chain to trigger signaling responses. In addition, using confocal and electron microscopy we demonstrated that the interaction between pDCs and A. fumigatus induced the formation of pDC extracellular traps (pETs) containing DNA and citrullinated histone H3. These structures closely resembled those of neutrophil extracellular traps (NETs). The microarray analysis of the pDC transcriptome upon A. fumigatus infection also demonstrated up-regulated expression of genes associated with apoptosis as well as type I interferon-induced genes. Thus, human pDCs directly recognize A. fumigatus hyphae via Dectin-2; this interaction results in cytokine release and antifungal activity. Moreover, hyphal stimulation of pDCs triggers a distinct pattern of pDC gene expression and leads to pET formation.
- Published
- 2015
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17. NADPH oxidase promotes neutrophil extracellular trap formation in pulmonary aspergillosis.
- Author
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Röhm M, Grimm MJ, D'Auria AC, Almyroudis NG, Segal BH, and Urban CF
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- Animals, Aspergillus fumigatus physiology, Hyphae physiology, Inflammation, Mice, Mice, Knockout, Pulmonary Alveoli cytology, Gene Expression Regulation, Enzymologic immunology, NADPH Oxidases metabolism, Neutrophils physiology, Pulmonary Aspergillosis enzymology
- Abstract
NADPH oxidase is a crucial enzyme in antimicrobial host defense and in regulating inflammation. Chronic granulomatous disease (CGD) is an inherited disorder of NADPH oxidase in which phagocytes are defective in generation of reactive oxidant intermediates. Aspergillus species are ubiquitous, filamentous fungi, which can cause invasive aspergillosis, a major cause of morbidity and mortality in CGD, reflecting the critical role for NADPH oxidase in antifungal host defense. Activation of NADPH oxidase in neutrophils can be coupled to the release of proteins and chromatin that comingle in neutrophil extracellular traps (NETs), which can augment extracellular antimicrobial host defense. NETosis can be driven by NADPH oxidase-dependent and -independent pathways. We therefore undertook an analysis of whether NADPH oxidase was required for NETosis in Aspergillus fumigatus pneumonia. Oropharyngeal instillation of live Aspergillus hyphae induced neutrophilic pneumonitis in both wild-type and NADPH oxidase-deficient (p47(phox-/-)) mice which had resolved in wild-type mice by day 5 but progressed in p47(phox-/-) mice. NETs, identified by immunostaining, were observed in lungs of wild-type mice but were absent in p47(phox-/-) mice. Using bona fide NETs and nuclear chromatin decondensation as an early NETosis marker, we found that NETosis required a functional NADPH oxidase in vivo and ex vivo. In addition, NADPH oxidase increased the proportion of apoptotic neutrophils. Together, our results show that NADPH oxidase is required for pulmonary clearance of Aspergillus hyphae and generation of NETs in vivo. We speculate that dual modulation of NETosis and apoptosis by NADPH oxidase enhances antifungal host defense and promotes resolution of inflammation upon infection clearance.
- Published
- 2014
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18. Candida albicans escapes from mouse neutrophils.
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Ermert D, Niemiec MJ, Röhm M, Glenthøj A, Borregaard N, and Urban CF
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- Animals, Candida albicans growth & development, Female, Gene Knock-In Techniques, Humans, Hyphae growth & development, Immunity, Innate, Male, Mice, Inbred C57BL, Neutrophils enzymology, Neutrophils microbiology, Peroxidase physiology, Reactive Oxygen Species metabolism, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins physiology, Respiratory Burst, Species Specificity, alpha-Defensins genetics, alpha-Defensins physiology, Candida albicans immunology, Immune Evasion, Mice immunology, Models, Animal, Neutrophils immunology
- Abstract
Candida albicans, the most commonly isolated human fungal pathogen, is able to grow as budding yeasts or filamentous forms, such as hyphae. The ability to switch morphology has been attributed a crucial role for the pathogenesis of C. albicans. To mimic disseminated candidiasis in humans, the mouse is the most widely used model organism. Neutrophils are essential immune cells to prevent opportunistic mycoses. To explore potential differences between the rodent infection model and the human host, we compared the interactions of C. albicans with neutrophil granulocytes from mice and humans. We revealed that murine neutrophils exhibited a significantly lower ability to kill C. albicans than their human counterparts. Strikingly, C. albicans yeast cells formed germ tubes upon internalization by murine neutrophils, eventually rupturing the neutrophil membrane and thereby, killing the phagocyte. On the contrary, growth and subsequent escape of C. albicans are blocked inside human neutrophils. According to our findings, this blockage in human neutrophils might be a result of higher levels of MPO activity and the presence of α-defensins. We therefore outline differences in antifungal immune defense between humans and mouse strains, which facilitates a more accurate interpretation of in vivo results.
- Published
- 2013
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19. Monocyte- and macrophage-targeted NADPH oxidase mediates antifungal host defense and regulation of acute inflammation in mice.
- Author
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Grimm MJ, Vethanayagam RR, Almyroudis NG, Dennis CG, Khan AN, D'Auria AC, Singel KL, Davidson BA, Knight PR, Blackwell TS, Hohl TM, Mansour MK, Vyas JM, Röhm M, Urban CF, Kelkka T, Holmdahl R, and Segal BH
- Subjects
- Acute Disease, Animals, Aspergillosis enzymology, Aspergillosis immunology, Aspergillosis pathology, Genetic Predisposition to Disease, Inflammation enzymology, Inflammation microbiology, Inflammation prevention & control, Lung enzymology, Lung immunology, Lung microbiology, Macrophages, Alveolar microbiology, Mice, Mice, Inbred C57BL, Mice, Knockout, Mice, Transgenic, Monocytes microbiology, NADPH Oxidases deficiency, NADPH Oxidases genetics, Zymosan pharmacology, Aspergillus fumigatus immunology, Macrophages, Alveolar enzymology, Macrophages, Alveolar immunology, Monocytes enzymology, Monocytes immunology, NADPH Oxidases physiology
- Abstract
Chronic granulomatous disease, an inherited disorder of the NADPH oxidase in which phagocytes are defective in the generation of superoxide anion and downstream reactive oxidant species, is characterized by severe bacterial and fungal infections and excessive inflammation. Although NADPH oxidase isoforms exist in several lineages, reactive oxidant generation is greatest in neutrophils, where NADPH oxidase has been deemed vital for pathogen killing. In contrast, the function and importance of NADPH oxidase in macrophages are less clear. Therefore, we evaluated susceptibility to pulmonary aspergillosis in globally NADPH oxidase-deficient mice versus transgenic mice with monocyte/macrophage-targeted NADPH oxidase activity. We found that the lethal inoculum was >100-fold greater in transgenic versus globally NADPH oxidase-deficient mice. Consistent with these in vivo results, NADPH oxidase in mouse alveolar macrophages limited germination of phagocytosed Aspergillus fumigatus spores. Finally, globally NADPH oxidase-deficient mice developed exuberant neutrophilic lung inflammation and proinflammatory cytokine responses to zymosan, a fungal cell wall-derived product composed principally of particulate β-glucans, whereas inflammation in transgenic and wild-type mice was mild and transient. Taken together, our studies identify a central role for monocyte/macrophage NADPH oxidase in controlling fungal infection and in limiting acute lung inflammation.
- Published
- 2013
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20. NETosis and NADPH oxidase: at the intersection of host defense, inflammation, and injury.
- Author
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Almyroudis NG, Grimm MJ, Davidson BA, Röhm M, Urban CF, and Segal BH
- Abstract
Neutrophils are armed with both oxidant-dependent and -independent pathways for killing pathogens. Activation of the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase constitutes an emergency response to infectious threat and results in the generation of antimicrobial reactive oxidants. In addition, NADPH oxidase activation in neutrophils is linked to activation of granular proteases and generation of neutrophil extracellular traps (NETs). NETosis involves the release of nuclear and granular components that can target extracellular pathogens. NETosis is activated during microbial threat and in certain conditions mimicking sepsis, and can result in both augmented host defense and inflammatory injury. In contrast, apoptosis, the physiological form of neutrophil death, not only leads to non-inflammatory cell death but also contributes to alleviate inflammation. Although there are significant gaps in knowledge regarding the specific contribution of NETs to host defense, we speculate that the coordinated activation of NADPH oxidase and NETosis maximizes microbial killing. Work in engineered mice and limited patient experience point to varying susceptibility of bacterial and fungal pathogens to NADPH oxidase versus NET constituents. Since reactive oxidants and NET constituents can injure host tissue, it is important that these pathways be tightly regulated. Recent work supports a role for NETosis in both acute lung injury and in autoimmunity. Knowledge gained about mechanisms that modulate NETosis may lead to novel therapeutic approaches to limit inflammation-associated injury.
- Published
- 2013
- Full Text
- View/download PDF
21. Vibrio cholerae evades neutrophil extracellular traps by the activity of two extracellular nucleases.
- Author
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Seper A, Hosseinzadeh A, Gorkiewicz G, Lichtenegger S, Roier S, Leitner DR, Röhm M, Grutsch A, Reidl J, Urban CF, and Schild S
- Subjects
- Animals, Female, Humans, Male, Mice, Immunity, Innate genetics, Mice, Knockout, Bacterial Proteins genetics, Bacterial Proteins immunology, Bacterial Proteins metabolism, Cholera enzymology, Cholera genetics, Cholera immunology, Cholera pathology, Deoxyribonucleases genetics, Deoxyribonucleases immunology, Deoxyribonucleases metabolism, Microbial Viability, Neutrophils immunology, Neutrophils metabolism, Neutrophils pathology, Vibrio cholerae enzymology, Vibrio cholerae genetics, Vibrio cholerae immunology
- Abstract
The Gram negative bacterium Vibrio cholerae is the causative agent of the secretory diarrheal disease cholera, which has traditionally been classified as a noninflammatory disease. However, several recent reports suggest that a V. cholerae infection induces an inflammatory response in the gastrointestinal tract indicated by recruitment of innate immune cells and increase of inflammatory cytokines. In this study, we describe a colonization defect of a double extracellular nuclease V. cholerae mutant in immunocompetent mice, which is not evident in neutropenic mice. Intrigued by this observation, we investigated the impact of neutrophils, as a central part of the innate immune system, on the pathogen V. cholerae in more detail. Our results demonstrate that V. cholerae induces formation of neutrophil extracellular traps (NETs) upon contact with neutrophils, while V. cholerae in return induces the two extracellular nucleases upon presence of NETs. We show that the V. cholerae wild type rapidly degrades the DNA component of the NETs by the combined activity of the two extracellular nucleases Dns and Xds. In contrast, NETs exhibit prolonged stability in presence of the double nuclease mutant. Finally, we demonstrate that Dns and Xds mediate evasion of V. cholerae from NETs and lower the susceptibility for extracellular killing in the presence of NETs. This report provides a first comprehensive characterization of the interplay between neutrophils and V. cholerae along with new evidence that the innate immune response impacts the colonization of V. cholerae in vivo. A limitation of this study is an inability for technical and physiological reasons to visualize intact NETs in the intestinal lumen of infected mice, but we can hypothesize that extracellular nuclease production by V. cholerae may enhance survival fitness of the pathogen through NET degradation.
- Published
- 2013
- Full Text
- View/download PDF
22. Myeloid-related protein-14 contributes to protective immunity in gram-negative pneumonia derived sepsis.
- Author
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Achouiti A, Vogl T, Urban CF, Röhm M, Hommes TJ, van Zoelen MA, Florquin S, Roth J, van 't Veer C, de Vos AF, and van der Poll T
- Subjects
- ATP-Binding Cassette Transporters immunology, ATP-Binding Cassette Transporters metabolism, Animals, Calgranulin B genetics, Calgranulin B metabolism, Cell Line, Humans, Klebsiella Infections microbiology, Lung immunology, Lung metabolism, Lung microbiology, Macrophages, Mice, Mice, Inbred C57BL, Mice, Knockout, Phagocytosis, Pneumonia, Bacterial microbiology, Sepsis microbiology, Calgranulin B immunology, Klebsiella Infections immunology, Klebsiella pneumoniae immunology, Neutrophils immunology, Pneumonia, Bacterial immunology, Sepsis immunology
- Abstract
Klebsiella (K.) pneumoniae is a common cause of pneumonia-derived sepsis. Myeloid related protein 8 (MRP8, S100A8) and MRP14 (S100A9) are the most abundant cytoplasmic proteins in neutrophils. They can form MRP8/14 heterodimers that are released upon cell stress stimuli. MRP8/14 reportedly exerts antimicrobial activity, but in acute fulminant sepsis models MRP8/14 has been found to contribute to organ damage and death. We here determined the role of MRP8/14 in K. pneumoniae sepsis originating from the lungs, using an established model characterized by gradual growth of bacteria with subsequent dissemination. Infection resulted in gradually increasing MRP8/14 levels in lungs and plasma. Mrp14 deficient (mrp14(-/-)) mice, unable to form MRP8/14 heterodimers, showed enhanced bacterial dissemination accompanied by increased organ damage and a reduced survival. Mrp14(-/-) macrophages were reduced in their capacity to phagocytose Klebsiella. In addition, recombinant MRP8/14 heterodimers, but not MRP8 or MRP14 alone, prevented growth of Klebsiella in vitro through chelation of divalent cations. Neutrophil extracellular traps (NETs) prepared from wildtype but not from mrp14(-/-) neutrophils inhibited Klebsiella growth; in accordance, the capacity of human NETs to kill Klebsiella was strongly impaired by an anti-MRP14 antibody or the addition of zinc. These results identify MRP8/14 as key player in protective innate immunity during Klebsiella pneumonia.
- Published
- 2012
- Full Text
- View/download PDF
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