TY  - JOUR
A1  - Eder, Sascha
A1  - Hollmann, Claudia
A1  - Mandasari, Putri
A1  - Wittmann, Pia
A1  - Schumacher, Fabian
A1  - Kleuser, Burkhard
A1  - Fink, Julian
A1  - Seibel, Jürgen
A1  - Schneider-Schaulies, Jürgen
A1  - Stigloher, Christian
A1  - Beyersdorf, Niklas
A1  - Dembski, Sofia
T1  - Synthesis and characterization of ceramide-containing liposomes as membrane models for different T cell subpopulations
JF  - Journal of Functional Biomaterials
N2  - A fine balance of regulatory (T\(_{reg}\)) and conventional CD4\(^+\) T cells (T\(_{conv}\)) is required to prevent harmful immune responses, while at the same time ensuring the development of protective immunity against pathogens. As for many cellular processes, sphingolipid metabolism also crucially modulates the T\(_{reg}\)/T\(_{conv}\) balance. However, our understanding of how sphingolipid metabolism is involved in T cell biology is still evolving and a better characterization of the tools at hand is required to advance the field. Therefore, we established a reductionist liposomal membrane model system to imitate the plasma membrane of mouse T\(_{reg}\) and T\(_{conv}\) with regards to their ceramide content. We found that the capacity of membranes to incorporate externally added azide-functionalized ceramide positively correlated with the ceramide content of the liposomes. Moreover, we studied the impact of the different liposomal preparations on primary mouse splenocytes in vitro. The addition of liposomes to resting, but not activated, splenocytes maintained viability with liposomes containing high amounts of C\(_{16}\)-ceramide being most efficient. Our data thus suggest that differences in ceramide post-incorporation into T\(_{reg}\) and T\(_{conv}\) reflect differences in the ceramide content of cellular membranes.
KW  - liposome
KW  - ceramide
KW  - cell membrane model
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286130
SN  - 2079-4983
VL  - 13
IS  - 3
ER  - 
TY  - JOUR
A1  - Peters, Simon
A1  - Kaiser, Lena
A1  - Fink, Julian
A1  - Schumacher, Fabian
A1  - Perschin, Veronika
A1  - Schlegel, Jan
A1  - Sauer, Markus
A1  - Stigloher, Christian
A1  - Kleuser, Burkhard
A1  - Seibel, Juergen
A1  - Schubert-Unkmeir, Alexandra
T1  - Click-correlative light and electron microscopy (click-AT-CLEM) for imaging and tracking azido-functionalized sphingolipids in bacteria
JF  - Scientific Reports
N2  - 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.
KW  - antimicrobials
KW  - biological techniques
KW  - imaging
KW  - microbiology
KW  - microbiology techniques
KW  - microscopy
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259147
VL  - 11
IS  - 1
ER  -