TY  - JOUR
A1  - Becam, Jérôme
A1  - Walter, Tim
A1  - Burgert, Anne
A1  - Schlegel, Jan
A1  - Sauer, Markus
A1  - Seibel, Jürgen
A1  - Schubert-Unkmeir, Alexandra
T1  - Antibacterial activity of ceramide and ceramide analogs against pathogenic Neisseria
JF  - Scientific Reports
N2  - 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.
KW  - ceramide analogs
KW  - Neisseria
KW  - ceramide
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159367
VL  - 7
ER  - 
TY  - JOUR
A1  - Ziegler, Sabrina
A1  - Weiss, Esther
A1  - Schmitt, Anna-Lena
A1  - Schlegel, Jan
A1  - Burgert, Anne
A1  - Terpitz, Ulrich
A1  - Sauer, Markus
A1  - Moretta, Lorenzo
A1  - Sivori, Simona
A1  - Leonhardt, Ines
A1  - Kurzai, Oliver
A1  - Einsele, Hermann
A1  - Loeffler, Juergen
T1  - CD56 Is a Pathogen Recognition Receptor on Human Natural Killer Cells
JF  - Scientific Reports
N2  - 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.
KW  - pattern recognition receptors
KW  - fungal infection
KW  - Aspergillus fumigatus
KW  - natural killer cells
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170637
VL  - 7
IS  - 6138
ER  -