@article{ZieglerWeissSchmittetal.2017, author = {Ziegler, Sabrina and Weiss, Esther and Schmitt, Anna-Lena and Schlegel, Jan and Burgert, Anne and Terpitz, Ulrich and Sauer, Markus and Moretta, Lorenzo and Sivori, Simona and Leonhardt, Ines and Kurzai, Oliver and Einsele, Hermann and Loeffler, Juergen}, title = {CD56 Is a Pathogen Recognition Receptor on Human Natural Killer Cells}, series = {Scientific Reports}, volume = {7}, journal = {Scientific Reports}, number = {6138}, doi = {10.1038/s41598-017-06238-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170637}, year = {2017}, abstract = {Aspergillus (A.) fumigatus is an opportunistic fungal mold inducing invasive aspergillosis (IA) in immunocompromised patients. Although antifungal activity of human natural killer (NK) cells was shown in previous studies, the underlying cellular mechanisms and pathogen recognition receptors (PRRs) are still unknown. Using flow cytometry we were able to show that the fluorescence positivity of the surface receptor CD56 significantly decreased upon fungal contact. To visualize the interaction site of NK cells and A. fumigatus we used SEM, CLSM and dSTORM techniques, which clearly demonstrated that NK cells directly interact with A. fumigatus via CD56 and that CD56 is re-organized and accumulated at this interaction site time-dependently. The inhibition of the cytoskeleton showed that the receptor re-organization was an active process dependent on actin re-arrangements. Furthermore, we could show that CD56 plays a role in the fungus mediated NK cell activation, since blocking of CD56 surface receptor reduced fungal mediated NK cell activation and reduced cytokine secretion. These results confirmed the direct interaction of NK cells and A. fumigatus, leading to the conclusion that CD56 is a pathogen recognition receptor. These findings give new insights into the functional role of CD56 in the pathogen recognition during the innate immune response.}, language = {en} } @article{WiegeringKorbThalheimeretal.2014, author = {Wiegering, Armin and Korb, Doreen and Thalheimer, Andreas and K{\"a}mmerer, Ulrike and Allmanritter, Jan and Matthes, Niels and Linnebacher, Michael and Schlegel, Nicolas and Klein, Ingo and Erg{\"u}n, S{\"u}leyman and Germer, Christoph-Thomas and Otto, Christoph}, title = {E7080 (Lenvatinib), a Multi-Targeted Tyrosine Kinase Inhibitor, Demonstrates Antitumor Activities Against Colorectal Cancer Xenografts}, doi = {10.1016/j.neo.2014.09.008}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-111165}, year = {2014}, abstract = {Clinical prognosis of metastasized colorectal carcinoma (CRC) is still not at desired levels and novel drugs are needed. Here, we focused on the multi-tyrosine kinase inhibitor E7080 (Lenvatinib) and assessed its therapeutic efficacy against human CRC cell lines in vitro and human CRC xenografts in vivo. The effect of E7080 on cell viability was examined on 10 humanCRCcell lines and humanendothelial cells (HUVEC). The inhibitory effect of E7080 on VEGF-induced angiogenesis was studied in an ex vivo mouse aortic ring angiogenesis assay. In addition, the efficacy of E7080 against xenografts derived fromCRC cell lines and CRC patient resection specimenswithmutated KRASwas investigated in vivo. Arelatively low cytotoxic effect of E7080 on CRC cell viabilitywas observed in vitro. Endothelial cells (HUVEC)weremore susceptible to the incubation with E7080. This is in line with the observation that E7080 demonstrated an anti-angiogenic effect in a three-dimensional ex vivo mouse aortic ring angiogenesis assay. E7080 effectively disrupted CRC cell-mediated VEGF-stimulated growth of HUVEC in vitro. Daily in vivo treatment with E7080 (5 mg/kg) significantly delayed the growth of KRAS mutated CRC xenografts with decreased density of tumor-associated vessel formations and without tumor regression. This observation is in line with results that E7080 did not significantly reduce the number of Ki67-positive cells in CRC xenografts. The results suggest antiangiogenic activity of E7080 at a dosage thatwas well tolerated by nudemice. E7080 may provide therapeutic benefits in the treatment of CRC with mutated KRAS.}, language = {en} } @phdthesis{Schlegel2021, author = {Schlegel, Jan}, title = {Super-Resolution Microscopy of Sphingolipids and Protein Nanodomains}, doi = {10.25972/OPUS-22959}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229596}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {The development of cellular life on earth is coupled to the formation of lipid-based biological membranes. Although many tools to analyze their biophysical properties already exist, their variety and number is still relatively small compared to the field of protein studies. One reason for this, is their small size and complex assembly into an asymmetric tightly packed lipid bilayer showing characteristics of a two-dimensional heterogenous fluid. Since membranes are capable to form dynamic, nanoscopic domains, enriched in sphingolipids and cholesterol, their detailed investigation is limited to techniques which access information below the diffraction limit of light. In this work, I aimed to extend, optimize and compare three different labeling approaches for sphingolipids and their subsequent analysis by the single-molecule localization microscopy (SMLM) technique direct stochastic optical reconstruction microscopy (dSTORM). First, I applied classical immunofluorescence by immunoglobulin G (IgG) antibody labeling to detect and quantify sphingolipid nanodomains in the plasma membrane of eukaryotic cells. I was able to identify and characterize ceramide-rich platforms (CRPs) with a size of ~ 75nm on the basal and apical membrane of different cell lines. Next, I used click-chemistry to characterize sphingolipid analogs in living and fixed cells. By using a combination of fluorescence microscopy and anisotropy experiments, I analyzed their accessibility and configuration in the plasma membrane, respectively. Azide-modified, short fatty acid side chains, were accessible to membrane impermeable dyes and localized outside the hydrophobic membrane core. In contrast, azide moieties at the end of longer fatty acid side chains were less accessible and conjugated dyes localized deeper within the plasma membrane. By introducing photo-crosslinkable diazirine groups or chemically addressable amine groups, I developed methods to improve their immobilization required for dSTORM. Finally, I harnessed the specific binding characteristics of non-toxic shiga toxin B subunits (STxBs) and cholera toxin B subunits (CTxBs) to label and quantify glycosphingolipid nanodomains in the context of Neisseria meningitidis infection. Under pyhsiological conditions, these glycosphingolipids were distributed homogenously in the plasma membrane but upon bacterial infection CTxB detectable gangliosides accumulated around invasive Neisseria meningitidis. I was able to highlight the importance of cell cycle dependent glycosphingolipid expression for the invasion process. Blocking membrane accessible sugar headgroups by pretreatment with CTxB significantly reduced the number of invasive bacteria which confirmed the importance of gangliosides for bacterial uptake into cells. Based on my results, it can be concluded that labeling of sphingolipids should be carefully optimized depending on the research question and applied microscopy technique. In particular, I was able to develop new tools and protocols which enable the characterization of sphingolipid nanodomains by dSTORM for all three labeling approaches.}, subject = {Sphingolipide}, language = {en} } @article{SchickIsbaryStueberetal.2012, author = {Schick, Martin Alexander and Isbary, Jobst Tobias and Stueber, Tanja and Brugger, Juergen and Stumpner, Jan and Schlegel, Nicolas and Roewer, Norbert and Eichelbroenner, Otto and Wunder, Christian}, title = {Effects of crystalloids and colloids on liver and intestine microcirculation and function in cecal ligation and puncture induced septic rodents}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-78151}, year = {2012}, abstract = {Background: Septic acute liver and intestinal failure is associated with a high mortality. We therefore investigated the influence of volume resuscitation with different crystalloid or colloid solutions on liver and intestine injury and microcirculation in septic rodents. Methods: Sepsis was induced by cecal ligation and puncture (CLP) in 77 male rats. Animals were treated with different crystalloids (NaCl 0.9\% (NaCl), Ringer's acetate (RA)) or colloids (Gelafundin 4\% (Gel), 6\% HES 130/0.4 (HES)). After 24 h animals were re-anesthetized and intestinal (n = 6/group) and liver microcirculation (n = 6/group) were obtained using intravital microscopy, as well as macrohemodynamic parameters were measured. Blood assays and organs were harvested to determine organ function and injury. Results: HES improved liver microcirculation, cardiac index and DO2-I, but significantly increased IL-1β, IL-6 and TNF-α levels and resulted in a mortality rate of 33\%. Gel infused animals revealed significant reduction of liver and intestine microcirculation with severe side effects on coagulation (significantly increased PTT and INR, decreased haemoglobin and platelet count). Furthermore Gel showed severe hypoglycemia, acidosis and significantly increased ALT and IL-6 with a lethality of 29\%. RA exhibited no derangements in liver microcirculation when compared to sham and HES. RA showed no intestinal microcirculation disturbance compared to sham, but significantly improved the number of intestinal capillaries with flow compared to HES. All RA treated animals survided and showed no severe side effects on coagulation, liver, macrohemodynamic or metabolic state. Conclusions: Gelatine 4\% revealed devastated hepatic and intestinal microcirculation and severe side effects in CLP induced septic rats, whereas the balanced crystalloid solution showed stabilization of macro- and microhemodynamics with improved survival. HES improved liver microcirculation, but exhibited significantly increased pro-inflammatory cytokine levels. Crystalloid infusion revealed best results in mortality and microcirculation, when compared with colloid infusion.}, subject = {Medizin}, language = {en} } @article{SchlegelSauer2020, author = {Schlegel, Jan and Sauer, Markus}, title = {Hochaufgel{\"o}ste Visualisierung einzelner Molek{\"u}le auf ganzen Zellen}, series = {BIOspektrum}, volume = {7}, journal = {BIOspektrum}, issn = {0947-0867}, doi = {10.1007/s12268-020-1501-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232365}, pages = {736-738}, year = {2020}, abstract = {Biological systems are dynamic and three-dimensional but many techniques allow only static and two-dimensional observation of cells. We used three-dimensional (3D) lattice light-sheet single-molecule localization microscopy (dSTORM) to investigate the complex interactions and distribution of single molecules in the plasma membrane of whole cells. Different receptor densities of the adhesion receptor CD56 at different parts of the cell highlight the importance and need of three-dimensional observation and analysis techniques.}, language = {de} } @article{SchlegelPetersDooseetal.2019, author = {Schlegel, Jan and Peters, Simon and Doose, S{\"o}ren and Schubert-Unkmeir, Alexandra and Sauer, Markus}, title = {Super-resolution microscopy reveals local accumulation of plasma membrane gangliosides at Neisseria meningitidis Invasion Sites}, series = {Frontiers in Cell and Developmental Biology}, volume = {7}, journal = {Frontiers in Cell and Developmental Biology}, number = {194}, doi = {10.3389/fcell.2019.00194}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-201639}, year = {2019}, abstract = {Neisseria meningitidis (meningococcus) is a Gram-negative bacterium responsible for epidemic meningitis and sepsis worldwide. A critical step in the development of meningitis is the interaction of bacteria with cells forming the blood-cerebrospinal fluid barrier, which requires tight adhesion of the pathogen to highly specialized brain endothelial cells. Two endothelial receptors, CD147 and the β2-adrenergic receptor, have been found to be sequentially recruited by meningococci involving the interaction with type IV pilus. Despite the identification of cellular key players in bacterial adhesion the detailed mechanism of invasion is still poorly understood. Here, we investigated cellular dynamics and mobility of the type IV pilus receptor CD147 upon treatment with pili enriched fractions and specific antibodies directed against two extracellular Ig-like domains in living human brain microvascular endothelial cells. Modulation of CD147 mobility after ligand binding revealed by single-molecule tracking experiments demonstrates receptor activation and indicates plasma membrane rearrangements. Exploiting the binding of Shiga (STxB) and Cholera toxin B (CTxB) subunits to the two native plasma membrane sphingolipids globotriaosylceramide (Gb3) and raft-associated monosialotetrahexosylganglioside GM1, respectively, we investigated their involvement in bacterial invasion by super-resolution microscopy. Structured illumination microscopy (SIM) and direct stochastic optical reconstruction microscopy (dSTORM) unraveled accumulation and coating of meningococci with GM1 upon cellular uptake. Blocking of CTxB binding sites did not impair bacterial adhesion but dramatically reduced bacterial invasion efficiency. In addition, cell cycle arrest in G1 phase induced by serum starvation led to an overall increase of GM1 molecules in the plasma membrane and consequently also in bacterial invasion efficiency. Our results will help to understand downstream signaling events after initial type IV pilus-host cell interactions and thus have general impact on the development of new therapeutics targeting key molecules involved in infection.}, language = {en} } @article{FeldbauerSchlegelWeissbeckeretal.2016, author = {Feldbauer, Katrin and Schlegel, Jan and Weissbecker, Juliane and Sauer, Frank and Wood, Phillip G. and Bamberg, Ernst and Terpitz, Ulrich}, title = {Optochemokine Tandem for Light-Control of Intracellular Ca\(^{2+}\)}, series = {PLoS ONE}, volume = {11}, journal = {PLoS ONE}, number = {10}, doi = {10.1371/journal.pone.0165344}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178921}, year = {2016}, abstract = {An optochemokine tandem was developed to control the release of calcium from endosomes into the cytosol by light and to analyze the internalization kinetics of G-protein coupled receptors (GPCRs) by electrophysiology. A previously constructed rhodopsin tandem was re-engineered to combine the light-gated Ca\(^{2+}\)-permeable cation channel Channelrhodopsin-2(L132C), CatCh, with the chemokine receptor CXCR4 in a functional tandem protein tCXCR4/CatCh. The GPCR was used as a shuttle protein to displace CatCh from the plasma membrane into intracellular areas. As shown by patch-clamp measurements and confocal laser scanning microscopy, heterologously expressed tCXCR4/CatCh was internalized via the endocytic SDF1/CXCR4 signaling pathway. The kinetics of internalization could be followed electrophysiologically via the amplitude of the CatCh signal. The light-induced release of Ca\(^{2+}\) by tandem endosomes into the cytosol via CatCh was visualized using the Ca\(^{2+}\)-sensitive dyes rhod2 and rhod2-AM showing an increase of intracellular Ca\(^{2+}\) in response to light.}, language = {en} } @article{GoetzKunzFinketal.2020, author = {G{\"o}tz, Ralph and Kunz, Tobias C. and Fink, Julian and Solger, Franziska and Schlegel, Jan and Seibel, J{\"u}rgen and Kozjak-Pavlovic, Vera and Rudel, Thomas and Sauer, Markus}, title = {Nanoscale imaging of bacterial infections by sphingolipid expansion microscopy}, series = {Nature Communications}, volume = {11}, journal = {Nature Communications}, doi = {10.1038/s41467-020-19897-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-231248}, year = {2020}, abstract = {Expansion microscopy (ExM) enables super-resolution imaging of proteins and nucleic acids on conventional microscopes. However, imaging of details of the organization of lipid bilayers by light microscopy remains challenging. We introduce an unnatural short-chain azide- and amino-modified sphingolipid ceramide, which upon incorporation into membranes can be labeled by click chemistry and linked into hydrogels, followed by 4x to 10x expansion. Confocal and structured illumination microscopy (SIM) enable imaging of sphingolipids and their interactions with proteins in the plasma membrane and membrane of intracellular organelles with a spatial resolution of 10-20nm. As our functionalized sphingolipids accumulate efficiently in pathogens, we use sphingolipid ExM to investigate bacterial infections of human HeLa229 cells by Neisseria gonorrhoeae, Chlamydia trachomatis and Simkania negevensis with a resolution so far only provided by electron microscopy. In particular, sphingolipid ExM allows us to visualize the inner and outer membrane of intracellular bacteria and determine their distance to 27.6 +/- 7.7nm. Imaging of lipid bilayers using light microscopy is challenging. Here the authors label cells using a short chain click-compatible ceramide to visualize mammalian and bacterial membranes with expansion microscopy.}, language = {en} } @article{PetersKaiserFinketal.2021, author = {Peters, Simon and Kaiser, Lena and Fink, Julian and Schumacher, Fabian and Perschin, Veronika and Schlegel, Jan and Sauer, Markus and Stigloher, Christian and Kleuser, Burkhard and Seibel, Juergen and Schubert-Unkmeir, Alexandra}, title = {Click-correlative light and electron microscopy (click-AT-CLEM) for imaging and tracking azido-functionalized sphingolipids in bacteria}, series = {Scientific Reports}, volume = {11}, journal = {Scientific Reports}, number = {1}, doi = {10.1038/s41598-021-83813-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-259147}, pages = {4300}, year = {2021}, abstract = {Sphingolipids, including ceramides, are a diverse group of structurally related lipids composed of a sphingoid base backbone coupled to a fatty acid side chain and modified terminal hydroxyl group. Recently, it has been shown that sphingolipids show antimicrobial activity against a broad range of pathogenic microorganisms. The antimicrobial mechanism, however, remains so far elusive. Here, we introduce 'click-AT-CLEM', a labeling technique for correlated light and electron microscopy (CLEM) based on the super-resolution array tomography (srAT) approach and bio-orthogonal click chemistry for imaging of azido-tagged sphingolipids to directly visualize their interaction with the model Gram-negative bacterium Neisseria meningitidis at subcellular level. We observed ultrastructural damage of bacteria and disruption of the bacterial outer membrane induced by two azido-modified sphingolipids by scanning electron microscopy and transmission electron microscopy. Click-AT-CLEM imaging and mass spectrometry clearly revealed efficient incorporation of azido-tagged sphingolipids into the outer membrane of Gram-negative bacteria as underlying cause of their antimicrobial activity.}, language = {en} } @article{HaackBaikerSchlegeletal.2021, author = {Haack, Stephanie and Baiker, Sarah and Schlegel, Jan and Sauer, Markus and Sparwasser, Tim and Langenhorst, Daniela and Beyersdorf, Niklas}, title = {Superagonistic CD28 stimulation induces IFN-γ release from mouse T helper 1 cells in vitro and in vivo}, series = {European Journal of Immunology}, volume = {51}, journal = {European Journal of Immunology}, number = {3}, doi = {10.1002/eji.202048803}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-239028}, pages = {738 -- 741}, year = {2021}, abstract = {Like human Th1 cells, mouse Th1 cells also secrete IFN-γ upon stimulation with a superagonistic anti-CD28 monoclonal antibody (CD28-SA). Crosslinking of the CD28-SA via FcR and CD40-CD40L interactions greatly increased IFN-γ release. Our data stress the utility of the mouse as a model organism for immune responses in humans.}, language = {en} } @article{SchneiderSchauliesSchumacherWiggeretal.2021, author = {Schneider-Schaulies, Sibylle and Schumacher, Fabian and Wigger, Dominik and Sch{\"o}l, Marie and Waghmare, Trushnal and Schlegel, Jan and Seibel, J{\"u}rgen and Kleuser, Burkhard}, title = {Sphingolipids: effectors and Achilles heals in viral infections?}, series = {Cells}, volume = {10}, journal = {Cells}, number = {9}, issn = {2073-4409}, doi = {10.3390/cells10092175}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245151}, year = {2021}, abstract = {As viruses are obligatory intracellular parasites, any step during their life cycle strictly depends on successful interaction with their particular host cells. In particular, their interaction with cellular membranes is of crucial importance for most steps in the viral replication cycle. Such interactions are initiated by uptake of viral particles and subsequent trafficking to intracellular compartments to access their replication compartments which provide a spatially confined environment concentrating viral and cellular components, and subsequently, employ cellular membranes for assembly and exit of viral progeny. The ability of viruses to actively modulate lipid composition such as sphingolipids (SLs) is essential for successful completion of the viral life cycle. In addition to their structural and biophysical properties of cellular membranes, some sphingolipid (SL) species are bioactive and as such, take part in cellular signaling processes involved in regulating viral replication. It is especially due to the progress made in tools to study accumulation and dynamics of SLs, which visualize their compartmentalization and identify interaction partners at a cellular level, as well as the availability of genetic knockout systems, that the role of particular SL species in the viral replication process can be analyzed and, most importantly, be explored as targets for therapeutic intervention.}, language = {en} } @article{BonigKuciKucietal.2019, author = {Bonig, Halvard and Ku{\c{c}}i, Zyrafete and Ku{\c{c}}i, Selim and Bakhtiar, Shahrzad and Basu, Oliver and Bug, Gesine and Dennis, Mike and Greil, Johann and Barta, Aniko and K{\´a}llay, Kriszti{\´a}n M. and Lang, Peter and Lucchini, Giovanna and Pol, Raj and Schulz, Ansgar and Sykora, Karl-Walter and Teichert von Luettichau, Irene and Herter-Sprie, Grit and Ashab Uddin, Mohammad and Jenkin, Phil and Alsultan, Abdulrahman and Buechner, Jochen and Stein, Jerry and Kelemen, Agnes and Jarisch, Andrea and Soerensen, Jan and Salzmann-Manrique, Emilia and Hutter, Martin and Sch{\"a}fer, Richard and Seifried, Erhard and Paneesha, Shankara and Novitzky-Basso, Igor and Gefen, Aharon and Nevo, Neta and Beutel, Gernot and Schlegel, Paul-Gerhardt and Klingebiel, Thomas and Bader, Peter}, title = {Children and adults with Refractory acute Graft-versus-Host Disease respond to treatment with the Mesenchymal Stromal cell preparation "MSC-FFM"—Outcome report of 92 patients}, series = {Cells}, volume = {8}, journal = {Cells}, number = {12}, issn = {2073-4409}, doi = {10.3390/cells8121577}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193878}, pages = {1577}, year = {2019}, abstract = {(1) Background: Refractory acute graft-versus-host disease (R-aGvHD) remains a leading cause of death after allogeneic stem cell transplantation. Survival rates of 15\% after four years are currently achieved; deaths are only in part due to aGvHD itself, but mostly due to adverse effects of R-aGvHD treatment with immunosuppressive agents as these predispose patients to opportunistic infections and loss of graft-versus-leukemia surveillance resulting in relapse. Mesenchymal stromal cells (MSC) from different tissues and those generated by various protocols have been proposed as a remedy for R-aGvHD but the enthusiasm raised by initial reports has not been ubiquitously reproduced. (2) Methods: We previously reported on a unique MSC product, which was generated from pooled bone marrow mononuclear cells of multiple third-party donors. The products showed dose-to-dose equipotency and greater immunosuppressive capacity than individually expanded MSCs from the same donors. This product, MSC-FFM, has entered clinical routine in Germany where it is licensed with a national hospital exemption authorization. We previously reported satisfying initial clinical outcomes, which we are now updating. The data were collected in our post-approval pharmacovigilance program, i.e., this is not a clinical study and the data is high-level and non-monitored. (3) Results: Follow-up for 92 recipients of MSC-FFM was reported, 88 with GvHD ≥°III, one-third only steroid-refractory and two-thirds therapy resistant (refractory to steroids plus ≥2 additional lines of treatment). A median of three doses of MSC-FFM was administered without apparent toxicity. Overall response rates were 82\% and 81\% at the first and last evaluation, respectively. At six months, the estimated overall survival was 64\%, while the cumulative incidence of death from underlying disease was 3\%. (4) Conclusions: MSC-FFM promises to be a safe and efficient treatment for severe R-aGvHD.}, language = {en} } @article{SpringerHeldMengolietal.2021, author = {Springer, Jan and Held, J{\"u}rgen and Mengoli, Carlo and Schlegel, Paul Gerhardt and Gamon, Florian and Tr{\"a}ger, Johannes and Kurzai, Oliver and Einsele, Hermann and Loeffler, Juergen and Eyrich, Matthias}, title = {Diagnostic performance of (1→3)-β-D-glucan alone and in combination with aspergillus PCR and galactomannan in serum of pediatric patients after allogeneic hematopoietic stem cell transplantation}, series = {Journal of Fungi}, volume = {7}, journal = {Journal of Fungi}, number = {3}, issn = {2309-608X}, doi = {10.3390/jof7030238}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-234179}, year = {2021}, abstract = {Data on biomarker-assisted diagnosis of invasive aspergillosis (IA) in pediatric patients is scarce. Therefore, we conducted a cohort study over two years including 404 serum specimens of 26 pediatric patients after allogeneic hematopoietic stem cell transplantation (alloSCT). Sera were tested prospectively twice weekly for Aspergillus-specific DNA, galactomannan (GM), and retrospectively for (1→3)-β-D-glucan (BDG). Three probable IA and two possible invasive fungal disease (IFD) cases were identified using the European Organization for Research and Treatment of Cancer and the Mycoses Study Group (EORTC/MSGERC) 2019 consensus definitions. Sensitivity and specificity for diagnosis of probable IA and possible IFD was 80\% (95\% confidential interval (CI): 28-99\%) and 55\% (95\% CI: 32-77\%) for BDG, 40\% (95\% CI: 5-85\%) and 100\% (95\% CI: 83-100\%) for GM, and 60\% (95\% CI: 15-95\%) and 95\% (95\% CI: 75-100\%) for Aspergillus-specific real-time PCR. However, sensitivities have to be interpreted with great caution due to the limited number of IA cases. Interestingly, the low specificity of BDG was largely caused by false-positive BDG results that clustered around the date of alloSCT. The following strategies were able to increase BDG specificity: two consecutive positive BDG tests for diagnosis (specificity 80\% (95\% CI: 56-94\%)); using an optimized cutoff value of 306 pg/mL (specificity 90\% (95\% CI: 68-99\%)) and testing BDG only after the acute posttransplant phase. In summary, BDG can help to diagnose IA in pediatric alloSCT recipients. However, due to the poor specificity either an increased cutoff value should be utilized or BDG results should be confirmed by an alternative Aspergillus assay.}, language = {en} } @article{KannapinSchmitzHansmannetal.2021, author = {Kannapin, Felix and Schmitz, Tobias and Hansmann, Jan and Schlegel, Nicolas and Meir, Michael}, title = {Measurements of transepithelial electrical resistance (TEER) are affected by junctional length in immature epithelial monolayers}, series = {Histochemistry and Cell Biology}, volume = {156}, journal = {Histochemistry and Cell Biology}, number = {6}, issn = {1432-119X}, doi = {10.1007/s00418-021-02026-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-267465}, pages = {609-616}, year = {2021}, abstract = {The measurement of transepithelial electrical resistance (TEER) is a common technique to determine the barrier integrity of epithelial cell monolayers. However, it is remarkable that absolute TEER values of similar cell types cultured under comparable conditions show an immense heterogeneity. Based on previous observations, we hypothesized that the heterogeneity of absolute TEER measurements can not only be explained by maturation of junctional proteins but rather by dynamics in the absolute length of cell junctions within monolayers. Therefore, we analyzed TEER in epithelial cell monolayers of Caco2 cells during their differentiation, with special emphasis on both changes in the junctional complex and overall cell morphology within monolayers. We found that in epithelial Caco2 monolayers TEER increased until confluency, then decreased for some time, which was then followed by an additional increase during junctional differentiation. In contrast, permeability of macromolecules measured at different time points as 4 kDA fluorescein isothiocyanate (FITC)-dextran flux across monolayers steadily decreased during this time. Detailed analysis suggested that this observation could be explained by alterations of junctional length along the cell borders within monolayers during differentiation. In conclusion, these observations confirmed that changes in cell numbers and consecutive increase of junctional length have a critical impact on TEER values, especially at stages of early confluency when junctions are immature.}, language = {en} } @article{BecamWalterBurgertetal.2017, author = {Becam, J{\´e}r{\^o}me and Walter, Tim and Burgert, Anne and Schlegel, Jan and Sauer, Markus and Seibel, J{\"u}rgen and Schubert-Unkmeir, Alexandra}, title = {Antibacterial activity of ceramide and ceramide analogs against pathogenic Neisseria}, series = {Scientific Reports}, volume = {7}, journal = {Scientific Reports}, doi = {10.1038/s41598-017-18071-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159367}, pages = {17627}, year = {2017}, abstract = {Certain fatty acids and sphingoid bases found at mucosal surfaces are known to have antibacterial activity and are thought to play a more direct role in innate immunity against bacterial infections. Herein, we analysed the antibacterial activity of sphingolipids, including the sphingoid base sphingosine as well as short-chain C\(_{6}\) and long-chain C\(_{16}\)-ceramides and azido-functionalized ceramide analogs against pathogenic Neisseriae. Determination of the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) demonstrated that short-chain ceramides and a ω-azido-functionalized C\(_{6}\)-ceramide were active against Neisseria meningitidis and N. gonorrhoeae, whereas they were inactive against Escherichia coli and Staphylococcus aureus. Kinetic assays showed that killing of N. meningitidis occurred within 2 h with ω-azido-C\(_{6}\)-ceramide at 1 X the MIC. Of note, at a bactericidal concentration, ω-azido-C\(_{6}\)-ceramide had no significant toxic effect on host cells. Moreover, lipid uptake and localization was studied by flow cytometry and confocal laser scanning microscopy (CLSM) and revealed a rapid uptake by bacteria within 5 min. CLSM and super-resolution fluorescence imaging by direct stochastic optical reconstruction microscopy demonstrated homogeneous distribution of ceramide analogs in the bacterial membrane. Taken together, these data demonstrate the potent bactericidal activity of sphingosine and synthetic short-chain ceramide analogs against pathogenic Neisseriae.}, language = {en} } @article{WeissSchlegelTerpitzetal.2020, author = {Weiss, Esther and Schlegel, Jan and Terpitz, Ulrich and Weber, Michael and Linde, J{\"o}rg and Schmitt, Anna-Lena and H{\"u}nniger, Kerstin and Marischen, Lothar and Gamon, Florian and Bauer, Joachim and L{\"o}ffler, Claudia and Kurzai, Oliver and Morton, Charles Oliver and Sauer, Markus and Einsele, Hermann and Loeffler, Juergen}, title = {Reconstituting NK Cells After Allogeneic Stem Cell Transplantation Show Impaired Response to the Fungal Pathogen Aspergillus fumigatus}, series = {Frontiers in Immunology}, volume = {11}, journal = {Frontiers in Immunology}, issn = {1664-3224}, doi = {10.3389/fimmu.2020.02117}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212581}, year = {2020}, abstract = {Delayed natural killer (NK) cell reconstitution after allogeneic stem cell transplantation (alloSCT) is associated with a higher risk of developing invasive aspergillosis. The interaction of NK cells with the human pathogen Aspergillus (A.) fumigatus is mediated by the fungal recognition receptor CD56, which is relocated to the fungal interface after contact. Blocking of CD56 signaling inhibits the fungal mediated chemokine secretion of MIP-1α, MIP-1β, and RANTES and reduces cell activation, indicating a functional role of CD56 in fungal recognition. We collected peripheral blood from recipients of an allograft at defined time points after alloSCT (day 60, 90, 120, 180). NK cells were isolated, directly challenged with live A. fumigatus germ tubes, and cell function was analyzed and compared to healthy age and gender-matched individuals. After alloSCT, NK cells displayed a higher percentage of CD56\(^{bright}\)CD16\(^{dim}\) cells throughout the time of blood collection. However, CD56 binding and relocalization to the fungal contact side were decreased. We were able to correlate this deficiency to the administration of corticosteroid therapy that further negatively influenced the secretion of MIP-1α, MIP-1β, and RANTES. As a consequence, the treatment of healthy NK cells ex vivo with corticosteroids abrogated chemokine secretion measured by multiplex immunoassay. Furthermore, we analyzed NK cells regarding their actin cytoskeleton by Structured Illumination Microscopy (SIM) and flow cytometry and demonstrate an actin dysfunction of NK cells shown by reduced F-actin content after fungal co-cultivation early after alloSCT. This dysfunction remains until 180 days post-alloSCT, concluding that further actin-dependent cellular processes may be negatively influenced after alloSCT. To investigate the molecular pathomechansism, we compared CD56 receptor mobility on the plasma membrane of healthy and alloSCT primary NK cells by single-molecule tracking. The results were very robust and reproducible between tested conditions which point to a different molecular mechanism and emphasize the importance of proper CD56 mobility.}, language = {en} } @article{GeigerKerstingSchlegeletal.2022, author = {Geiger, Nina and Kersting, Louise and Schlegel, Jan and Stelz, Linda and F{\"a}hr, Sofie and Diesendorf, Viktoria and Roll, Valeria and Sostmann, Marie and K{\"o}nig, Eva-Maria and Reinhard, Sebastian and Brenner, Daniela and Schneider-Schaulies, Sibylle and Sauer, Markus and Seibel, J{\"u}rgen and Bodem, Jochen}, title = {The acid ceramidase is a SARS-CoV-2 host factor}, series = {Cells}, volume = {11}, journal = {Cells}, number = {16}, issn = {2073-4409}, doi = {10.3390/cells11162532}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286105}, year = {2022}, abstract = {SARS-CoV-2 variants such as the delta or omicron variants, with higher transmission rates, accelerated the global COVID-19 pandemic. Thus, novel therapeutic strategies need to be deployed. The inhibition of acid sphingomyelinase (ASM), interfering with viral entry by fluoxetine was reported. Here, we described the acid ceramidase as an additional target of fluoxetine. To discover these effects, we synthesized an ASM-independent fluoxetine derivative, AKS466. High-resolution SARS-CoV-2-RNA FISH and RTqPCR analyses demonstrate that AKS466 down-regulates viral gene expression. It is shown that SARS-CoV-2 deacidifies the lysosomal pH using the ORF3 protein. However, treatment with AKS488 or fluoxetine lowers the lysosomal pH. Our biochemical results show that AKS466 localizes to the endo-lysosomal replication compartments of infected cells, and demonstrate the enrichment of the viral genomic, minus-stranded RNA and mRNAs there. Both fluoxetine and AKS466 inhibit the acid ceramidase activity, cause endo-lysosomal ceramide elevation, and interfere with viral replication. Furthermore, Ceranib-2, a specific acid ceramidase inhibitor, reduces SARS-CoV-2 replication and, most importantly, the exogenous supplementation of C6-ceramide interferes with viral replication. These results support the hypotheses that the acid ceramidase is a SARS-CoV-2 host factor.}, language = {en} } @article{BrennerGeigerSchlegeletal.2023, author = {Brenner, Daniela and Geiger, Nina and Schlegel, Jan and Diesendorf, Viktoria and Kersting, Louise and Fink, Julian and Stelz, Linda and Schneider-Schaulies, Sibylle and Sauer, Markus and Bodem, Jochen and Seibel, J{\"u}rgen}, title = {Azido-ceramides, a tool to analyse SARS-CoV-2 replication and inhibition — SARS-CoV-2 is inhibited by ceramides}, series = {International Journal of Molecular Sciences}, volume = {24}, journal = {International Journal of Molecular Sciences}, number = {8}, issn = {1422-0067}, doi = {10.3390/ijms24087281}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313581}, year = {2023}, abstract = {Recently, we have shown that C6-ceramides efficiently suppress viral replication by trapping the virus in lysosomes. Here, we use antiviral assays to evaluate a synthetic ceramide derivative α-NH2-ω-N3-C6-ceramide (AKS461) and to confirm the biological activity of C6-ceramides inhibiting SARS-CoV-2. Click-labeling with a fluorophore demonstrated that AKS461 accumulates in lysosomes. Previously, it has been shown that suppression of SARS-CoV-2 replication can be cell-type specific. Thus, AKS461 inhibited SARS-CoV-2 replication in Huh-7, Vero, and Calu-3 cells up to 2.5 orders of magnitude. The results were confirmed by CoronaFISH, indicating that AKS461 acts comparable to the unmodified C6-ceramide. Thus, AKS461 serves as a tool to study ceramide-associated cellular and viral pathways, such as SARS-CoV-2 infections, and it helped to identify lysosomes as the central organelle of C6-ceramides to inhibit viral replication.}, language = {en} }