TY  - JOUR
A1  - Silva-Vilches, Cinthia
A1  - Pletinckx, Katrien
A1  - Lohnert, Miriam
A1  - Pavlovic, Vladimir
A1  - Ashour, Diyaaeldin
A1  - John, Vini
A1  - Vendelova, Emilia
A1  - Kneitz, Susanne
A1  - Zhou, Jie
A1  - Chen, Rena
A1  - Reinheckel, Thomas
A1  - Mueller, Thomas D.
A1  - Bodem, Jochen
A1  - Lutz, Manfred B.
T1  - Low doses of cholera toxin and its mediator cAMP induce CTLA-2 secretion by dendritic cells to enhance regulatory T cell conversion
JF  - PLoS ONE
N2  - Immature or semi-mature dendritic cells (DCs) represent tolerogenic maturation stages that can convert naive T cells into Foxp3\(^{+}\) induced regulatory T cells (iTreg). Here we found that murine bone marrow-derived DCs (BM-DCs) treated with cholera toxin (CT) matured by up-regulating MHC-II and costimulatory molecules using either high or low doses of CT (CT\(^{hi}\), CT\(^{lo}\)) or with cAMP, a known mediator CT signals. However, all three conditions also induced mRNA of both isoforms of the tolerogenic molecule cytotoxic T lymphocyte antigen 2 (CTLA-2α and CTLA-2β). Only DCs matured under CT\(^{hi}\) conditions secreted IL-1β, IL-6 and IL-23 leading to the instruction of Th17 cell polarization. In contrast, CT\(^{lo}\)- or cAMP-DCs resembled semi-mature DCs and enhanced TGF-β-dependent Foxp3\(^{+}\) iTreg conversion. iTreg conversion could be reduced using siRNA blocking of CTLA-2 and reversely, addition of recombinant CTLA-2α increased iTreg conversion in vitro. Injection of CT\(^{lo}\)- or cAMP-DCs exerted MOG peptide-specific protective effects in experimental autoimmune encephalomyelitis (EAE) by inducing Foxp3\(^{+}\) Tregs and reducing Th17 responses. Together, we identified CTLA-2 production by DCs as a novel tolerogenic mediator of TGF-β-mediated iTreg induction in vitro and in vivo. The CT-induced and cAMP-mediated up-regulation of CTLA-2 also may point to a novel immune evasion mechanism of Vibrio cholerae.
KW  - small interfering RNAs
KW  - toxins
KW  - regulatory T cells
KW  - T cells
KW  - cytokines
KW  - cholera
KW  - cell differentiation
KW  - immune evasion
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158244
VL  - 12
IS  - 7
ER  - 
TY  - JOUR
A1  - Geiger, Nina
A1  - Kersting, Louise
A1  - Schlegel, Jan
A1  - Stelz, Linda
A1  - Fähr, Sofie
A1  - Diesendorf, Viktoria
A1  - Roll, Valeria
A1  - Sostmann, Marie
A1  - König, Eva-Maria
A1  - Reinhard, Sebastian
A1  - Brenner, Daniela
A1  - Schneider-Schaulies, Sibylle
A1  - Sauer, Markus
A1  - Seibel, Jürgen
A1  - Bodem, Jochen
T1  - The acid ceramidase is a SARS-CoV-2 host factor
JF  - Cells
N2  - 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.
KW  - SARS-CoV-2
KW  - ceramides
KW  - ceramidase
KW  - fluoxetine
KW  - acid sphingomyelinase
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286105
SN  - 2073-4409
VL  - 11
IS  - 16
ER  - 
TY  - JOUR
A1  - Brenner, Daniela
A1  - Geiger, Nina
A1  - Schlegel, Jan
A1  - Diesendorf, Viktoria
A1  - Kersting, Louise
A1  - Fink, Julian
A1  - Stelz, Linda
A1  - Schneider-Schaulies, Sibylle
A1  - Sauer, Markus
A1  - Bodem, Jochen
A1  - Seibel, Jürgen
T1  - Azido-ceramides, a tool to analyse SARS-CoV-2 replication and inhibition — SARS-CoV-2 is inhibited by ceramides
JF  - International Journal of Molecular Sciences
N2  - 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.
KW  - ceramides
KW  - SARS-CoV-2
KW  - azido-ceramides
KW  - sphingolipids
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-313581
SN  - 1422-0067
VL  - 24
IS  - 8
ER  -