TY - JOUR A1 - Nguyen, Minh Thu A1 - Kraft, Beatrice A1 - Yu, Wenqi A1 - Demicrioglu, Dogan Doruk A1 - Hertlein, Tobias A1 - Burian, Marc A1 - Schmaler, Mathias A1 - Boller, Klaus A1 - Bekeredjian-Ding, Isabelle A1 - Ohlsen, Knut A1 - Schittek, Birgit A1 - Götz, Friedrich T1 - The vSa\(\alpha\) Specific Lipoprotein Like Cluster (lpl) of S. aureus USA300 Contributes to Immune Stimulation and Invasion in Human Cells JF - PLoS Pathogens N2 - All Staphylococcus aureus genomes contain a genomic island, which is termed vSa\(\alpha\) and characterized by two clusters of tandem repeat sequences, i.e. the exotoxin (set) and 'lipoprotein-like' genes (lpl). Based on their structural similarities the vSa\(\alpha\) islands have been classified as type I to IV. The genomes of highly pathogenic and particularly epidemic S. aureus strains (USA300, N315, Mu50, NCTC8325, Newman, COL, JH1 or JH9) belonging to the clonal complexes CC5 and CC8 bear a type I vSa\(\alpha\) island. Since the contribution of the lpl gene cluster encoded in the vSa\(\alpha\) island to virulence is unclear to date, we deleted the entire lpl gene cluster in S. aureus USA300. The results showed that the mutant was deficient in the stimulation of pro-inflammatory cytokines in human monocytes, macrophages and keratinocytes. Purified lipoprotein Lpl1 was further shown to elicit a TLR2-dependent response. Furthermore, heterologous expression of the USA300 lpl cluster in other S. aureus strains enhanced their immune stimulatory activity. Most importantly, the lpl cluster contributed to invasion of S. aureus into human keratinocytes and mouse skin and the non-invasive S. carnosus expressing the lpl gene cluster became invasive. Additionally, in a murine kidney abscess model the bacterial burden in the kidneys was higher in wild type than in mutant mice. In this infection model the lpl cluster, thus, contributes to virulence. The present report is one of the first studies addressing the role of the vSa\(\alpha\) encoded lpl gene cluster in staphylococcal virulence. The finding that the lpl gene cluster contributes to internalization into non-professional antigen presenting cells such as keratinocytes high-lights the lpl as a new cell surface component that triggers host cell invasion by S. aureus. Increased invasion in murine skin and an increased bacterial burden in a murine kidney abscess model suggest that the lpl gene cluster serves as an important virulence factor. KW - resistant Staphylococcus-aureus KW - bacterial lipoproteins KW - internalization KW - evolution KW - fibronectin-binding protein KW - toll-like receptor 2 KW - epithelial cells KW - genome sequence KW - activation KW - mechanisms Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151856 VL - 11 IS - 6 ER - TY - JOUR A1 - Mielich-Süss, Benjamin A1 - Wagner, Rabea M. A1 - Mietrach, Nicole A1 - Hertlein, Tobias A1 - Marincola, Gabriella A1 - Ohlsen, Knut A1 - Geibel, Sebastian A1 - Lopez, Daniel T1 - Flotillin scaffold activity contributes to type VII secretion system assembly in Staphylococcus aureus JF - PLoS Pathogens N2 - Scaffold proteins are ubiquitous chaperones that promote efficient interactions between partners of multi-enzymatic protein complexes; although they are well studied in eukaryotes, their role in prokaryotic systems is poorly understood. Bacterial membranes have functional membrane microdomains (FMM), a structure homologous to eukaryotic lipid rafts. Similar to their eukaryotic counterparts, bacterial FMM harbor a scaffold protein termed flotillin that is thought to promote interactions between proteins spatially confined to the FMM. Here we used biochemical approaches to define the scaffold activity of the flotillin homolog FloA of the human pathogen Staphylococcus aureus, using assembly of interacting protein partners of the type VII secretion system (T7SS) as a case study. Staphylococcus aureus cells that lacked FloA showed reduced T7SS function, and thus reduced secretion of T7SS-related effectors, probably due to the supporting scaffold activity of flotillin. We found that the presence of flotillin mediates intermolecular interactions of T7SS proteins. We tested several small molecules that interfere with flotillin scaffold activity, which perturbed T7SS activity in vitro and in vivo. Our results suggest that flotillin assists in the assembly of S. aureus membrane components that participate in infection and influences the infective potential of this pathogen. KW - flotillin KW - scaffold protein KW - Staphylococcus aureus KW - type VII secretion system Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170035 VL - 13 IS - 11 ER - TY - JOUR A1 - Umstätter, Florian A1 - Domhan, Cornelius A1 - Hertlein, Tobias A1 - Ohlsen, Knut A1 - Mühlberg, Eric A1 - Kleist, Christian A1 - Zimmermann, Stefan A1 - Beijer, Barbro A1 - Klika, Karel D. A1 - Haberkorn, Uwe A1 - Mier, Walter A1 - Uhl, Philipp T1 - Vancomycin Resistance Is Overcome by Conjugation of Polycationic Peptides JF - Angewandte Chemie International Edition N2 - Multidrug‐resistant bacteria represent one of the biggest challenges facing modern medicine. The increasing prevalence of glycopeptide resistance compromises the efficacy of vancomycin, for a long time considered as the last resort for the treatment of resistant bacteria. To reestablish its activity, polycationic peptides were conjugated to vancomycin. By site‐specific conjugation, derivatives that bear the peptide moiety at four different sites of the antibiotic were synthesized. The most potent compounds exhibited an approximately 1000‐fold increased antimicrobial activity and were able to overcome the most important types of vancomycin resistance. Additional blocking experiments using d‐Ala‐d‐Ala revealed a mode of action beyond inhibition of cell‐wall formation. The antimicrobial potential of the lead candidate FU002 for bacterial infection treatments could be demonstrated in an in vivo study. Molecular imaging and biodistribution studies revealed that conjugation engenders superior pharmacokinetics. KW - antibiotics KW - bacterial resistance KW - glycopeptide antibiotics KW - peptide conjugates KW - vancomycin Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-215550 VL - 59 IS - 23 SP - 8823 EP - 8827 ER - TY - JOUR A1 - Jarick, Marcel A1 - Bertsche, Ute A1 - Stahl, Mark A1 - Schultz, Daniel A1 - Methling, Karen A1 - Lalk, Michael A1 - Stigloher, Christian A1 - Steger, Mirco A1 - Schlosser, Andreas A1 - Ohlsen, Knut T1 - The serine/threonine kinase Stk and the phosphatase Stp regulate cell wall synthesis in Staphylococcus aureus JF - Scientific Reports N2 - The cell wall synthesis pathway producing peptidoglycan is a highly coordinated and tightly regulated process. Although the major components of bacterial cell walls have been known for decades, the complex regulatory network controlling peptidoglycan synthesis and many details of the cell division machinery are not well understood. The eukaryotic-like serine/threonine kinase Stk and the cognate phosphatase Stp play an important role in cell wall biosynthesis and drug resistance in S. aureus. We show that stp deletion has a pronounced impact on cell wall synthesis. Deletion of stp leads to a thicker cell wall and decreases susceptibility to lysostaphin. Stationary phase Δstp cells accumulate peptidoglycan precursors and incorporate higher amounts of incomplete muropeptides with non-glycine, monoglycine and monoalanine interpeptide bridges into the cell wall. In line with this cell wall phenotype, we demonstrate that the lipid II:glycine glycyltransferase FemX can be phosphorylated by the Ser/Thr kinase Stk in vitro. Mass spectrometric analyses identify Thr32, Thr36 and Ser415 as phosphoacceptors. The cognate phosphatase Stp dephosphorylates these phosphorylation sites. Moreover, Stk interacts with FemA and FemB, but is unable to phosphorylate them. Our data indicate that Stk and Stp modulate cell wall synthesis and cell division at several levels. KW - bacterial transcription KW - pathogens KW - cell wall synthesis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177333 VL - 8 IS - 13693 ER - TY - JOUR A1 - Masota, Nelson E. A1 - Ohlsen, Knut A1 - Schollmayer, Curd A1 - Meinel, Lorenz A1 - Holzgrabe, Ulrike T1 - Isolation and characterization of galloylglucoses effective against multidrug-resistant strains of Escherichia coli and Klebsiella pneumoniae JF - Molecules N2 - The search for new antibiotics against multidrug-resistant (MDR), Gram-negative bacteria is crucial with respect to filling the antibiotics development pipeline, which is subject to a critical shortage of novel molecules. Screening of natural products is a promising approach for identifying antimicrobial compounds hosting a higher degree of novelty. Here, we report the isolation and characterization of four galloylglucoses active against different MDR strains of Escherichia coli and Klebsiella pneumoniae. A crude acetone extract was prepared from Paeonia officinalis Linnaeus leaves, and bioautography-guided isolation of active compounds from the extract was performed by liquid–liquid extraction, as well as open column, flash, and preparative chromatographic methods. Isolated active compounds were characterized and elucidated by a combination of spectroscopic and spectrometric techniques. In vitro antimicrobial susceptibility testing was carried out on E. coli and K. pneumoniae using 2 reference strains and 13 strains hosting a wide range of MDR phenotypes. Furthermore, in vivo antibacterial activities were assessed using Galleria mellonella larvae, and compounds 1,2,3,4,6-penta-O-galloyl-β-d-glucose, 3-O-digalloyl-1,2,4,6-tetra-O-galloyl-β-d-glucose, 6-O-digalloyl-1,2,3,4-tetra-O-galloyl-β-d-glucose, and 3,6-bis-O-digalloyl-1,2,4-tri-O-galloyl-β-d-glucose were isolated and characterized. They showed minimum inhibitory concentration (MIC) values in the range of 2–256 µg/mL across tested bacterial strains. These findings have added to the number of known galloylglucoses from P. officinalis and highlight their potential against MDR Gram-negative bacteria. KW - antimicrobial resistance KW - Enterobacteriaceae KW - Paeonia KW - gallotannins KW - isolation KW - structural elucidation KW - Escherichia coli KW - Klebsiella pneumoniae Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286179 SN - 1420-3049 VL - 27 IS - 15 ER - TY - JOUR A1 - Seethaler, Marius A1 - Hertlein, Tobias A1 - Hopke, Elisa A1 - Köhling, Paul A1 - Ohlsen, Knut A1 - Lalk, Michael A1 - Hilgeroth, Andreas T1 - Novel effective fluorinated benzothiophene-indole hybrid antibacterials against S. aureus and MRSA strains JF - Pharmaceuticals N2 - Increasing antibacterial drug resistance threatens global health, unfortunately, however, efforts to find novel antibacterial agents have been scaled back by the pharmaceutical industry due to concerns about a poor return on investment. Nevertheless, there is an urgent need to find novel antibacterial compounds to combat antibacterial drug resistance. The synthesis of novel drugs from natural sources is mostly cost-intensive due to those drugs’ complicated structures. Therefore, it is necessary to find novel antibacterials by simple synthesis to become more attractive for industrial production. We succeeded in the discovery of four antibacterial compound (sub)classes accessible in a simple one-pot reaction based on fluorinated benzothiophene-indole hybrids. They have been evaluated against various S. aureus and MRSA strains. Structure- and substituent-dependent activities have been found within the (sub)classes and promising lead compounds have been identified. In addition, bacterial pyruvate kinase was found to be the molecular target of the active compounds. In conclusion, simple one-pot synthesis of benzothiophene-indoles represents a promising strategy for the search of novel antimicrobial compounds. KW - antibacterial drug resistance KW - structure activity KW - synthesis KW - inhibition KW - substituent Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-288253 SN - 1424-8247 VL - 15 IS - 9 ER - TY - JOUR A1 - Hung, Sophia A1 - Kasperkowitz, Amelie A1 - Kurz, Florian A1 - Dreher, Liane A1 - Diessner, Joachim A1 - Ibrahim, Eslam S. A1 - Schwarz, Stefan A1 - Ohlsen, Knut A1 - Hertlein, Tobias T1 - Next-generation humanized NSG-SGM3 mice are highly susceptible to Staphylococcus aureus infection JF - Frontiers in Immunology N2 - Humanized hemato-lymphoid system mice, or humanized mice, emerged in recent years as a promising model to study the course of infection of human-adapted or human-specific pathogens. Though Staphylococcus aureus infects and colonizes a variety of species, it has nonetheless become one of the most successful human pathogens of our time with a wide armory of human-adapted virulence factors. Humanized mice showed increased vulnerability to S. aureus compared to wild type mice in a variety of clinically relevant disease models. Most of these studies employed humanized NSG (NOD-scid IL2Rgnull) mice which are widely used in the scientific community, but show poor human myeloid cell reconstitution. Since this immune cell compartment plays a decisive role in the defense of the human immune system against S. aureus, we asked whether next-generation humanized mice, like NSG-SGM3 (NOD-scid IL2Rgnull-3/GM/SF) with improved myeloid reconstitution, would prove to be more resistant to infection. To our surprise, we found the contrary when we infected humanized NSG-SGM3 (huSGM3) mice with S. aureus: although they had stronger human immune cell engraftment than humanized NSG mice, particularly in the myeloid compartment, they displayed even more pronounced vulnerability to S. aureus infection. HuSGM3 mice had overall higher numbers of human T cells, B cells, neutrophils and monocytes in the blood and the spleen. This was accompanied by elevated levels of pro-inflammatory human cytokines in the blood of huSGM3 mice. We further identified that the impaired survival of huSGM3 mice was not linked to higher bacterial burden nor to differences in the murine immune cell repertoire. Conversely, we could demonstrate a correlation of the rate of humanization and the severity of infection. Collectively, this study suggests a detrimental effect of the human immune system in humanized mice upon encounter with S. aureus which might help to guide future therapy approaches and analysis of virulence mechanisms. KW - humanized mice KW - Staphylococcus aureus KW - MRSA KW - NSG KW - NSG-SGM3 KW - staphylococcal abscess KW - Staphylococcus aureus immune response KW - humanized hemato-lymphoid mice Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-306966 VL - 14 ER - TY - JOUR A1 - Bruchhagen, Christin A1 - Jarick, Marcel A1 - Mewis, Carolin A1 - Hertlein, Tobias A1 - Niemann, Silke A1 - Ohlsen, Knut A1 - Peters, Georg A1 - Planz, Oliver A1 - Ludwig, Stephan A1 - Ehrhardt, Christina T1 - Metabolic conversion of CI-1040 turns a cellular MEK-inhibitor into an antibacterial compound JF - Scientific Reports N2 - Influenza virus (IV) infections cause severe respiratory illnesses that can be complicated by bacterial super-infections. Previously, we identified the cellular Raf-MEK-ERK cascade as a promising antiviral target. Inhibitors of MEK, such as CI-1040, showed potent antiviral activity. However, it remained unclear if this inhibitor and its active form, ATR-002, might sensitize host cells to either IV or secondary bacterial infections. To address these questions, we studied the anti-pathogen activity of ATR-002 in comparison to CI-1040, particularly, its impact on Staphylococcus aureus (S. aureus), which is a major cause of IV super-infections. We analysed IV and S. aureus titres in vitro during super-infection in the presence and absence of the drugs and characterized the direct impact of ATR-002 on bacterial growth and phenotypic changes. Importantly, neither CI-1040 nor ATR-002 treatment led to increased bacterial titres during super-infection, indicating that the drug does not sensitize cells for bacterial infection. In contrast, we rather observed reduced bacterial titres in presence of ATR-002. Surprisingly, ATR-002 also led to reduced bacterial growth in suspension cultures, reduced stress- and antibiotic tolerance without resistance induction. Our data identified for the first time that a particular MEK-inhibitor metabolite exhibits direct antibacterial activity, which is likely due to interference with the bacterial PknB kinase/Stp phosphatase signalling system. KW - antimicrobials KW - pathogens Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-221648 VL - 8 ER - TY - JOUR A1 - Fan, Sook-Ha A1 - Ebner, Patrick A1 - Reichert, Sebstian A1 - Hertlein, Tobias A1 - Zabel, Susanne A1 - Lankapalli, Aditya Kumar A1 - Nieselt, Kay A1 - Ohlsen, Knut A1 - Götz, Friedrich T1 - MpsAB is important for Staphylococcus aureus virulence and growth at atmospheric CO2 levels JF - Nature Communications N2 - The mechanisms behind carbon dioxide (CO2) dependency in non-autotrophic bacterial isolates are unclear. Here we show that the Staphylococcus aureus mpsAB operon, known to play a role in membrane potential generation, is crucial for growth at atmospheric CO2 levels. The genes mpsAB can complement an Escherichia coli carbonic anhydrase (CA) mutant, and CA from E. coli can complement the S. aureus delta-mpsABC mutant. In comparison with the wild type, S. aureus mps mutants produce less hemolytic toxin and are less virulent in animal models of infection. Homologs of mpsA and mpsB are widespread among bacteria and are often found adjacent to each other on the genome. We propose that MpsAB represents a dissolved inorganic carbon transporter, or bicarbonate concentrating system, possibly acting as a sodium bicarbonate cotransporter. KW - bacterial physiology KW - bacteriology KW - pathogens Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227624 VL - 10 ER -